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SR1 Operation

283

© 2014 Stanford Research Systems

2.9.3

Digital-Analog

The Digital-Analog selection lists basic Audio Analyzer measurements with a digital stimulus and an
analog response, i.e. a DAC. The 

digital generator

 is configured with the stimulus signal. The sampling

rate of the high-resolution analog converter is set to the digital OSR, so both domains are operating with
the same samplling rate. 

What you'll need to configure for all these setups:

Change the digital output parameters (connector, sample rate, bit resolution) to match the input of the
DACt being tested. Set the 

analog inputs

 to the appropriate connector and input coupling. 

FFT

This setup configures SR1 for a basic audio band FFT. The Hi-resolution converter is selected for
maximum dynamic range. The frequency range of the FFT is 1/2 the sampling rate of the digital output.
The A0 analyzer is configured as a dual channel FFT analyze continuous averaging.. The Digital
Generator is loaded with a lsine waveform set to a default frequency of 1 kHz and an amplitude of 1 FFS.
Page2 contains a graph displaying the A and B channel power spectra while Page 3 contains a graph
displaying the A and B channel time records.

What you'll need to configure:

If your'e using the digital generator, adjust the amplitude and frequency of the signal to match your
requirements. Otherwise you can turn the generator off. The amount of 

averaging

 in the FFT analyzer can

be adjusted to suit the noise level of your signal. The FFT resolution is defaulted to 4k points, adjust this
to obtain the proper balance of update rate vs. frequency resolution

Frequency Response

This setup configures SR1 for a stereo audio-band frequency response sweep. The Hi-resolution
converter is selected for maximum input dynamic range. The Time Domain Detector is selected for the
A0 analyzer. The Digital Generator is loaded with a sine waveform. Page2 contains a graph displaying
the A and B channel frequency response. The sweep controller is programmed to sweep the sine
frequency from 20 Hz to 20 kHz in 22 logarithmic steps. 

What you'll need to configure:

Adjust the the sine amplitude to match the equipment being tested. The number of points in the sweep
can be changed to give faster sweeps or higher resolution sweeps. The 

settling parameters

 can be

adjusted to fit the noise levels of the signals being measured.

Wideband FFT

This setup is similar to the audio-band FFT setup described above except that the analog input sampling
rate is set to OSRx2 so that the FFT bandwidth is twice as large.  The A0 analyzer is configured as a
dual channel FFT analyzer with continuous averaging.. The Digital Generator is loaded with a low-
distortion sine waveform set to a default frequency of 1 kHz and an amplitude of 1 Vrms. Page2 contains
a graph displaying the A and B channel power spectra while Page 3 contains a graph displaying the A
and B channel time records.

What you'll need to configure:

If your'e using the digital generator, adjust the amplitude and frequency of the signal to match your
requirements. Otherwise you can turn the generator off. The amount of 

averaging

 in the FFT analyzer can

Содержание SR1

Страница 1: ...sion 3 0 0 January 2014 Distribution in the UK Ireland Lambda Photometrics Limited Lambda House Batford Mill Harpenden Herts AL5 5BZ United Kingdom E info lambdaphoto co uk W www lambdaphoto co uk T 4...

Страница 2: ...erator Panel 41 Analog Generator Units 43 Analog Generator Waveforms 57 Digital Generator Panel 60 Digital Generator Units 62 Digital Generator Waveforms 76 Analog Inputs Panel 79 Digital I O Panel 87...

Страница 3: ...ject Drive 237 Pow er Options 238 Date Time 238 Virtual Keyboard 238 Updating SR1 241 7 Automation Menu 242 Remote Interface Panel 243 Scripting Window 252 Learning Mode 253 8 Quick Measurement Menu 2...

Страница 4: ...SR1 Operation Manual 4 2014 Stanford Research Systems 293 2 Rear Panel Descritpion 296 3 Specifications 305 4 Filter Reference 306 5 File Reference 310 6 Hardware Reference Index 312...

Страница 5: ...Part I Getting Started Audio...

Страница 6: ...alled The instrument has a 3 wire power cord Be sure to connect it to a properly grounded outlet to guard against electrical shock After connecting the power cord to an AC power source the unit can be...

Страница 7: ...Getting Started 7 2014 Stanford Research Systems...

Страница 8: ...Minor Printing Corrections 2 6 5 10 ajm Updated for SR1 v1 1 6 2 7 7 10 ajm Updated for SR1 v1 2 2 8 6 11 ajm Updated for SR1 v1 4 3 0 1 14 ajm Updated for SR1 v2 1 13 Copyright and Trademark Acknowle...

Страница 9: ...ranges from 160 Vrms down to 62 mVrms SR1 s analog inputs are autoranging meaning that for most input signals the analyzer automatically sets the input range without any user interaction Digital Audi...

Страница 10: ...which can be synchronized with the digital audio output or input signal to perform cross domain measurements Sweeps and Free Run SR1 operates in two different measurement modes free run and sweep In f...

Страница 11: ...tter measurement capabilities of the Jitter Analyzer Remote Interfacing SR1 Supports a variety of remote interfaces IEEE 488 2 GPIB SR1 has a rear panel IEEE 488 connector and fully supports the IEEE...

Страница 12: ...SR1 Operation Manual 12 2014 Stanford Research Systems...

Страница 13: ...Keyboard Control SR1 can be used with an external mouse and keyboard The mouse and keyboard must be connected to the rear panel connectors before the instrument is turned on to be properly recognized...

Страница 14: ...button on the speedbar Pause Pauses and resumes both sweeps and free run mode Equivalent to pressing the and buttons on the speedbar Run Starts free run mode Equivalent to pressing on the speedbar Tra...

Страница 15: ...Calls up the virtual keyboard Translate graph up down Once pressed the keys will move the data in the current graph up and down Press Esc to exit this mode Zoom Y axis Once pressed the keys will zoom...

Страница 16: ...A1 analyzer panel F4 Auto reference analyzer A0 Moves the current A0 level A and B values to the dBrA and dBrB reference values Ctrl F4 Auto reference analyzer A1 Moves the current A1 level A and B v...

Страница 17: ...era x1012 Note that the front panel keypad contains dedicated keys for the unit modifiers just to the right of the Enter key To complete the entry press the Enter key on the front panel or an external...

Страница 18: ...current value of the display is saved as the reference and subsequent updates are displayed as follows Mode Operation Standard Each update to the Unit Display s value is displayed Data is displayed in...

Страница 19: ...r These three panels may automatically open when SR1 is powered up SR1 Speedbar Note that the icons for the Analog Inputs panels and the Analog Generator panel are both orange SR1 uses orange to denot...

Страница 20: ...created Look at the Time Domain Detector panel and change the source from Digital A to Analog A The Converter field will read HiRes indicating that the analyzer is using SR1 s 24 bit High Resolution...

Страница 21: ...ote that the measured THD N ratio is 60 dB 1 mV 1 V 60 dB To show how much more SR1 brings to a standard distortion measurement select the second analyzer A1 as the FFT1 analyzer When the panel is dis...

Страница 22: ...he FFT results we ll need to create a graph Click on Page 2 of the page control to give us some room for the graph and click on the icon to create a new graph Maximize the graph with the standard maxi...

Страница 23: ...age 1 of the page control and in the bandwidth control of the FFT analyzer select 500 Hz In the Center Frequency field select 1 kHz We re narrowing the bandwidth by a factor of 64 still using 1k FFT l...

Страница 24: ...e the sweep occurs at fixed time intervals Internal Sweeps where the sweep occurs at fixed values of some internal parameter and External Sweeps where the sweep occurs at fixed values of some external...

Страница 25: ...select Log Step Size Next we need to select that data that will be measured in the sweep Up to 6 separate measurements can be recorded at each sweep point Click on the Sweep Data to specify the sweep...

Страница 26: ...p node and select THD Ratio A Select a log X axis to match the log sweep we just specified and select dB as the Y axis units with the unit entry controls Select a Y axis range from 95 to 10 dB Now sta...

Страница 27: ...Part II SR1 Operation Audio...

Страница 28: ...he entire instrument setup to a configuration file Save Partial Configuration Saves the entire instrument setup to a configuration file Load Configuration Loads setup information from a configuration...

Страница 29: ...ll panels and displays are recorded in the configuration file After loading the file the instrument state will be exactly what it was when saved The trace data option governs how SR1 will save data st...

Страница 30: ...nfiguration allows a choice of which portions of the instrument setup will be saved to the SR1 configuration file After selecting this option the Save Partial Configuration dialog box is diplayed Sele...

Страница 31: ...the standard Windows file open dialog box After selecting the file a dialog is displayed allowing selection of individual configuration areas The default is to load all the configuration information i...

Страница 32: ...indow of the program including menus and borders to the current printer Printer and paper options are selected from the File Print Setup dialog Note that File Print SR1 Screen always prints the entire...

Страница 33: ...tup displays the standard Windows print setup dialog box When running the SR1 program from a Windows computer use whatever printers have already been installed When using the SR1 instrument use the To...

Страница 34: ...t and copies it to the clipboard Copy Copies the currently selected text to the clipboard without deleting it Paste Copies the clipboard contents to the current cursor location Delete Deletes the curr...

Страница 35: ...he title Analyzer Panels which can operate in either domain have either the light blue or orange bar depending on whether the analyzer is operating in the digital or analog domain The following panel...

Страница 36: ...o all waveforms Note that the SR1 Analog Generator is completely separate and independent of the Digital Audio Generator The two generators operate simultaneously and independently with different wave...

Страница 37: ...connector configuration See the diagram below Unbal Gnd Outputs to the both the XLR and BNC connectors The BNC shield and XLR pin 3 are connected to chassis ground through a 5 resistor XLR pin 1 is co...

Страница 38: ...SR1 Operation Manual 38 2014 Stanford Research Systems Analog Generator Output Connections Output Impedance selects the Analog Generator output impedance...

Страница 39: ...l be assigned to channel A When the mode is changed from stereo to mono all channel B waveforms are deleted and the channel A waveforms are output on both channels Amplitude Controls The Channel Gain...

Страница 40: ...nerator burst as opposed to synchronous burst Generator Burst Mode selects the burst triggering mode Timed The waveform outputs at the high amplitude then the low amplitude and repeats The total perio...

Страница 41: ...response included 2 3 1 1 Analog Generator Units The amplitude and frequency of generator waveforms can be specified using a variety of units all of which are useful in different audio test scenarios...

Страница 42: ...o a specified load taking into account the output impedance of the generator If the amplitude is measured across the open circuited output terminals with a high impedance meter you may get a different...

Страница 43: ...ms for each channel the tab title contains a channel designator indicating which channel the waveform is associated with If the generator is in mono output mode the channel designator is omitted and t...

Страница 44: ...ator trigger capable will be the source of all generator triggers The Analog Generator Waveforms In the following list waveforms that may not be combined with other waveforms are marked with an asteri...

Страница 45: ...determined by the Burst On Time control Ext Gated The waveform amplitude is determined by the TTL gating signal applied to the rear panel TTL burst trigger input When the external signal is high the g...

Страница 46: ...e controls as with all SR1 waveforms the peak value of the noise output The crest factor of the noise waveform the ratio of the peak value to the rms value of the noise is approximately 4 The Repeat c...

Страница 47: ...rrelation of an MLS sequence is a delta function simplify the calculation of the impulse response Because SR1 uses a full 2 channel FFT analyzer to make impulse response measurements it is not necessa...

Страница 48: ...ction with generator bursting to generate a burst USASI signal suitable for transmitter testing Frequency Spectrum of USASI Noise 100 Hz 6dB oct hipass 320 Hz 6 dB oct lopass Square Wave SR1 square wa...

Страница 49: ...lected generator sample rate The lowest amplitude sample has the value assigned in the Low Amplitude control The highest amplitude sample has the value given in the High Amplitude control 1 kHz Ramp w...

Страница 50: ...d where memory allows Otherwise linear interpolation is used A maximum table length of 128 kpoints is allowed subject to other waveforms or instrument features using the DSP memory The arbitrary wavef...

Страница 51: ...o ensure cross domain sampling rate compatibility use the following sampling rate selections for the generator and analyzer Type of Measurement Generator Fs Analyzer Fs Analog Source Digital Measureme...

Страница 52: ...factor the variable sweep rate chirp has The lower crest factor makes it much more suitable waveform for audio testing The chirp waveform outputs a generator trigger once each cycle Be sure to use gen...

Страница 53: ...sfer Function Measurements with Sweeps J Audio Eng Soc vol 49 pp 443 471 June 2001 They report better results using log sine stimulus compared to MLS stimulus for a wide range of audio DUTs One partic...

Страница 54: ...t only the amplitude is specified on the waveform tab The Export button allows the current multitone waveform to be saved in arbitrary waveform format for off line analysis Because of the special prop...

Страница 55: ...equency with an exactly equal number of positive and negative samples the exact squarewave frequency is chosen by the generator depending on the generator Fs to be as close as possible to the squarewa...

Страница 56: ...e record of the FFT Analyzer If the output waveform still points up the device maintains polarity If the waveform points down the device is inverting Polarity Waveform Non Inverted And Inverted Consta...

Страница 57: ...on describes the controls and settings of the digital generator that are relevant to all waveforms Note that the controls on the generator panel and the waveform tabs are mainly concerned with the pro...

Страница 58: ...en on the Digital I O panel Waveform Controls The New button displays the Waveform Selection Submenu The selected waveform will either be added to the output for one or both channels depending on the...

Страница 59: ...nd turn off when the sweep is completed The large green red On Off buttons turn on and off their respective channels while the Invert buttons invert the output for each channel Reference Controls The...

Страница 60: ...selected waveform amplitude however the Total Channel Amplitude control will display the amplitude with the EQ response included 2 3 2 1 Digital Generator Units The amplitude and frequency of generato...

Страница 61: ...fixed relationship of peak voltage to peak to peak voltage for a sinewave If the value of V FS is 1 Vrms for instance then an amplitude of 2 0 Vpp would correspond to an amplitude of 1 Vrms which in...

Страница 62: ...gives a waveform frequency of 200 kHz 2 3 2 2 Digital Generator Waveforms SR1 s Digital Generator is capable of generating an enormous variety of different audio waveforms from simple sines to complex...

Страница 63: ...ing rate OSR The current OSR is displayed at the top of the digital generator panel Generator Trigger Certain generator waveforms can generate a trigger known as a generator trigger which can be used...

Страница 64: ...of the generated noise If not checked the repeat interval is sufficiently long that it won t observable under most conditions If however it is desired for the noise to repeat after a fixed interval c...

Страница 65: ...e MLS waveform because of its historical association with impulse response measurements Amplitude controls as with all SR1 waveforms the peak value of the noise output The crest factor of the MLS wave...

Страница 66: ...R If Precision Frequencies is checked square wave frequencies will be limited to these perfect frequencies If Precision Frequencies is unchecked the digital generator will interpolate a square wave at...

Страница 67: ...amplitude control is assigned to the maximum value found in the table The absolute scaling of the table values does not affect the output waveform However when operating at arbitrary output rates the...

Страница 68: ...nalyzer when using the chirp waveform Selection of the associated FFT Analyzer is done with the Chirp Source control Chirp Source Associated Analyzer A0 FFT1 Analyzer 0 Single Channel FFT Analyzer A0...

Страница 69: ...nusoid whose frequency is swept in a logarithmic fashion over the frequency span of its associated FFT analyzer The log sine chirp waveform has a pink frequency roll off of 3 dB oct The log sine chirp...

Страница 70: ...e response measurement of a consumer stereo amplifier shown below When the purely linear response is gated and transformed back into the frequency domain a much better measurement of the DUT frequency...

Страница 71: ...192 kHz the low frequency can be set between 10 Hz and 1 kHz The High Frequency can be anywhere down to 5x the low frequency The Amplitude Ratio low freq high freq can be set to either 1 1 or 4 1 with...

Страница 72: ...See the IMD Analyzer section for more details Polarity Check Waveform The polarity check waveform uses a phased combination of two sine waves to produce a deliberately asymmetric waveform that points...

Страница 73: ...t can be specified as a hex word or in any of the standard digital generator amplitude units The polarity of the constant can be controlled with the radio buttons at the bottom of the panel Digital Co...

Страница 74: ...eform outputs 5 complete square wave cycles of the ten smallest digital codes in succession followed by an equivalent interval of digital zero The length of each half cylce of a square wave is equal t...

Страница 75: ...te jitter due intersymbol interference in digital audio signal paths with reduced bandwdiths such as long cables The Jtest waveform is primarily a square wave at OSR 4 but the dc level is slightly shi...

Страница 76: ...en autoranging is off The smallest input range allowed by SR1 is 62 5 mVrms the largest is 160 Vrms In the Input Configuration box is the control to set the input connector Input Configuration Connect...

Страница 77: ...f this occurs the input voltage range will be shown in red as shown below Remove the input and reset the range manually to restore normal operation Hi Res Converter Sampling Rate Selection The second...

Страница 78: ...rd Research Systems Optional Input Filters The final tab on the Analog Inputs Panel contains the selection controls for the Optional Filters on the analog input boards See the SR1 Hardware Reference f...

Страница 79: ...pp to 2 55 Vpp can be selected for the BNC outputs while amplitudes from 10 mVpp to 10 2 Vpp are available for the XLR outputs Output amplitudes are calibrated only when the outputs are correctly term...

Страница 80: ...input is connected directly to the output of the digital generator The Dual connector checkbox selects dual connector input mode In dual connector mode SR1 expects two digital audio data streams left...

Страница 81: ...transmission over long cable runs Original Digital Audio Carrier After Long Cable Run Using SR1 s CableSim Long Cable Run Input EQ Digital Input Sample Rate Controls Select the Digital Audio Input Sam...

Страница 82: ...n the corresponding status condition is good and red when the status condition changes to bad The 6 status conditions detected are Status Condition Meaning CRC For AES EBU digital audio streams an 8 b...

Страница 83: ...isplays the delay from the z preamble beginning of digital audio block of the digital audio output signal to the z preamble of the digital audio input signal When When Delay Mode is set to RefOut DigI...

Страница 84: ...block This can be an indication that the bit is stuck Dark Green indicates that the bit changes value over the block Bright green indicates that the bit is on in the first frame of the block Because...

Страница 85: ...deviations of transitions in the digital audio carrier signal from their ideal times SR1 has two main methods for viewing jitter The Jitter Analyzer uses a phased lock loop to demodulate the jitter p...

Страница 86: ...response pairs or by calculation from a set of pole and zero locations The structure of EQ Files is detailed in the File Reference section Use the button to open a file dialog to specify the EQ File...

Страница 87: ...n and controls the transmitted channel status information Channel status information is organized according to either the AES EBU professional standard or the SPDIF consumer standard SR1 relies on AES...

Страница 88: ...mediately reflected in the hexadecimal status display along the bottom of the panel However changes made to the hexadecimal transmit panel are not reflected back in the status controls The status cont...

Страница 89: ...udio block Incorrect A changing incorrect CRC byte is sent with each digital audio block Zero The CRC byte is set to zero Received Status Bits The grouping of the received status display for both prof...

Страница 90: ...e most significant bit of the hexadecimal word corresponds to the user bit furthest from the start of the block Thus setting the value in byte 1 to 80 sets user bit number 15 out of 184 high The top l...

Страница 91: ...p point A settled measurement is a measurement whose variability has decreased below a user configured threshold and is considered suitable for final results Each SR1 measurement can have completely d...

Страница 92: ...the Sweep Source Pressing the Source button opens the Sweep Source Selection Window The different sweep sources are organized in a tree structure Click on the appropriate source Time Internal Externa...

Страница 93: ...d by the Step Size after each sweep point If Log Step Size is checked the sweep progression is logarithmic and the source parameter is multiplied by the sweep increment after each sweep point If the l...

Страница 94: ...sweep source it requires that the reading be Settled Refer to the Settling Panel for information on the different types of settling To configure an external sweep first make sure that the appropriate...

Страница 95: ...Start Sweep At parameter controls the starting of the external sweep Start Sweep At Within Tolerance The external sweep starts when a settled measurement of the sweep source is within tolerance of the...

Страница 96: ...iguration Panel On each tab the network selection determines whether unbalanced BNC or balanced XLR inputs or outputs will be swept The number of steps determines how many points will be taken The num...

Страница 97: ...up the analyzers before configuring the sweep Other Sweep Parameters Pre Sweep Delay sets a fixed delay between the time when the sweep starts and the time when the analyzer begins measruing the first...

Страница 98: ...he final sweep data at the expense of having to possibly wait longer for a settled measurement The correct value of the precision depends on the measurement and application and can usually only be det...

Страница 99: ...rance of the previous point the previous point is within the tolerance of the next previous point etc for a total of nPoints Average The result of the last nPoints measurements are averaged together a...

Страница 100: ...B The speaker and both headphone channels are fed the current output of the analog generator B channel Analog Gen A B The left and right headphone channels are fed the A and B channels of the analog...

Страница 101: ...s a realtime analog signal to the rear panel A0 Monitor connector which corresponds to the input signal after the notch bandpass filter and any bandwidth limiting or weighting filters have been applie...

Страница 102: ...figuring the generator and the analyzer Details of the analyzer configuration are discussed in the MultiTone Analyzer section The MultiTone configuration panel discussed here is concerned with details...

Страница 103: ...rithm selected in the frequency distribution control Multitone Frequency Distribution Linear The desired number of tones will be distributed between the frequency limits with an approximately uniform...

Страница 104: ...the the A and B channel Usually this will be the same number of tones in the Desired of Tones control The Edit Tones button displays the Edit Tones panel The Edit Tones Panel The Edit Tones panel all...

Страница 105: ...erence signal Not currently implemented Video NTSC Selects a standard NTSC composite video signal connected to the rear panel Video Ref In BNC connector The expected frequency is 15 7343 kHz Video SEC...

Страница 106: ...de is generated from the received channel status bits in each block and compared to the value stored in the last byte of the channel status block Red indicates a CRC mismatch Lock Green indicates that...

Страница 107: ...terodyne moving the FFT frequency range are included Dual Channel FFT FFT2 Provides dual channel FFT functionality Measurements include power spectrum and time record for both channels plus frequency...

Страница 108: ...ross domain measurements Selection of the Hi Res converter sampling rate is made on the Analog Inputs Panel Digital Audio inputs do not involve a choice of converter and the converter field is fixed a...

Страница 109: ...els have the same frequency Analyzer Trigger Most analyzers can operate in a triggered mode The FFT analyzers for instance use the trigger to synchronize the start of the FFT time record The Time Doma...

Страница 110: ...fixed at the same ratio that applies to a sinewave This can cause some confusion due to the fact that in normal usage an amplitude of 1 Vrms implies not just a magnitude and unit of measurement but a...

Страница 111: ...specified in the References Tab dBm Decibels relative to 1 mW into a load specified by the dBm Reference in the References Tab dBm 20 0 log10 Vrms 1mW Load Z Note that the load is for calculation pur...

Страница 112: ...et in the analyzer references tab For example with a V FS value of 2 Vrms an amplitude of 20 dBVrms corresponds to 0 1 Vrms which in turn corresponds to an amplitude of 0 05 FFS dBu Decibels relative...

Страница 113: ...ncy Reference A value of 500 dHz with a reference of 2 kHz gives a waveform frequency of 2 5 kHz Fref Percent of the Frequency Reference A frequency value of 50 Fref with a reference value of 10 kHz g...

Страница 114: ...tab has fields which contain the reference quantities for the analyzer units Note that all analyzers share one set of analyzer units there are not separate sets of references for the FFT analyzer and...

Страница 115: ...nt of the phase between the two channels These values are displayed at the bottom of the analyzer panel The second set of operations the Amplitude Chain is performed only on the selected channel The s...

Страница 116: ...e total noise and distortion present in the input signal THD N Ratio The ratio of the amplitude to the level of the selected channel is displayed The notch filter is always selected This selection dis...

Страница 117: ...ed channel Next adjustable analog gain from 0 to 66 dB is applied to the post filter signal The purpose of this gain is to amplify the post filter signal which in the case of a THD N measurement is ty...

Страница 118: ...e g A1 if the TDD is active on A0 or A0 if the TDD is active on A1 If the Other Analyzer is an FFT analyzer whose input is set to Other Analyzer the FFT analyzer will display the spectrum of the post...

Страница 119: ...b of the TDD panel The frequency can be fixed or tuned to the measured input frequency any of the generator frequencies or the current sweep frequency When possible Sweep or Generator should be chosen...

Страница 120: ...undamental level enough so that the postfilter gain can amplify the resulting noise distortion signal to full scale on the amplitude ADC and a second notch implemented by the DSP processor which cuts...

Страница 121: ...0 5 0 6 0 7 0 8 0 9 1 1 1 1 2 1 3 1 4 1 5 180 160 140 120 100 80 60 40 20 0 Notch Filter for Digital and Analog HiRes Inputs For HiRes analog and digital audio inputs the bandpass filters with 1 3 1...

Страница 122: ...ch Systems 10 0 3 10 0 1 10 0 1 10 0 3 120 100 80 60 40 20 0 20 Normalized Freq Response dB Software Bandpass Filters 1 3 1 6 1 12 1 24 Octave Digital and Analog HiRes Inputs for HiBw analog inputs a...

Страница 123: ...tuning source from the drop down control When the tuning source is set to Measured Freq the notch bandpass filter tracks the measured frequency of the selected input When set to one of the generator c...

Страница 124: ...7 1998 r2004 section 4 2 2 2 Passband ripple is 2 dB Stopband attenuation is 60 dB and the ratio of passband edge to stopband edge is 1 2 AES 40 kHz Selects a 4 pole elliptic high pass filter with a p...

Страница 125: ...A Wt A weighting filter is applied A weighting is specified in ANSI standard S1 4 1983 and is typically used for noise and THD N measurements with audio applications C Msg Wt The C Msg weighting filt...

Страница 126: ...n for greater than half scale and red for overloaded The AutoGain setting should keep the indicator in the green range If the level indicator jumps around too much the gain can be set manually to a se...

Страница 127: ...24 to apply the full 32k line resolution to a smaller portion of the frequency located anywhere within the full range For example the graph below shows the output of a typical device when subjected to...

Страница 128: ...time record Unless the input signal happens to be periodic in the time record discontinuities at the beginning and end of the time record will appear as significant broadening of the true spectrum of...

Страница 129: ...ime record be triggered so that the signal waveform will have the same phase relative to the beginning of the time record for each averaged FFT The linear spectrum has phase information associated wit...

Страница 130: ...The FFT1 panel contains the normal input source selection controls and level indicators common to all analyzers However a few items unique to the FFT1 analyzer are worth noting Unlike the RMS levels...

Страница 131: ...tive to the full DC to Fs 2 frequency range Aliasing Aliasing arises in sampled data systems because the real world filters used to protect A D converters have finite cutoff slopes Each of the SR1 s A...

Страница 132: ...implies that no averaging is performed In this case the magnitude of the Power Spectrum and Linear Spectrum are the same and simply become the magnitude of the last individual FFT Fixed Length averag...

Страница 133: ...ectrum The spectrum shown below on the left is the unwindowed spectrum of two sinewaves of arbitrary frequency The spectrum is completely distorted by the artifacts associated with the time record dis...

Страница 134: ...he Variable Time window is on 1 during the portion of the time record specified by the Variable Time Window Limits Outside of that interval the window is 0 The transitions between the off and on segme...

Страница 135: ...dd harmonics alternates between 0 and 180 However in the first spectrum the phase pattern of the harmonics is obscured by the noise generated by bins without any amplitude Phase Spectrum of Square Wav...

Страница 136: ...in IEEE Std 743 1995 is intended to be used for noise measurements associated with voice transmission telecommunications CCITT The CCITT weighting filter defined by ITU T Recommendation O 41 is anoth...

Страница 137: ...of 64 kHz and with Time Display Interpolation turned off Turning on Time Display Interpolation shown below on the right gives a much more accurate representation of the original signal Time Record wit...

Страница 138: ...timulus which although having a uniform frequency content takes many repeated shots to converge to an accurate result or swept measurements which require a separate measurement at each frequency point...

Страница 139: ...us chirp signal For the same reason be sure to select the Uniform window when using the synchronous chirp Window functions attenuate the beginning and the end of the timre record for the FFT analyzers...

Страница 140: ...n this case interestingly the dominant distortion product is not a harmonic but the 12 5 kHz subharmonic As it turns out this function generator generates it s signals at 1 2 the output frequency and...

Страница 141: ...ual Channel Response Measurement The diagram above shows a typical two channel measurement setup SR1 s Generator provides the stimulus signal which can be a broadband source such as noise or the FFT c...

Страница 142: ...2N real time record points are used to compute an FFT of N complex points Each FFT is then averaged in two different ways The Power Spectrum is computed by computing the power for each spectrum taking...

Страница 143: ...is small To minimize this volatility SR1 uses a standard technique called the Tri Spectral Average when computing the dual channel frequency response If we multiply the numerator and denominator of th...

Страница 144: ...ence Frequency Response and Coherence of Elliptical Filter Impulse Response SR1 computes the impulse response by taking the inverse FFT of the complex magnitude and phase frequency response Only porti...

Страница 145: ...response due to the sound directly transmitted from the loudspeaker to the microphone the response includes several reflections from nearby walls The calculated frequency response including the direct...

Страница 146: ...immediately obvious from the impulse response graph it is more evident in the computed ETC The ETC is calculated by finding an appropriate imaginary part for the impulse response in the same way that...

Страница 147: ...channel coherence of the A and B signals Values near one indicate good input output correlation while values near zero indicate the output consists mostly of uncorrelated noise Impulse Response The I...

Страница 148: ...nuous input data stream necessary to compute RMS levels is not be available Likewise the fact that continuous data is unavailable means that the A B phase computation which also requires continuous in...

Страница 149: ...However when aliasing is potentially a problem the box can be unchecked in which case only FFT lines that are fully alias protected are displayed Areas of the spectrum that are not fully protected are...

Страница 150: ...w Selection It is well known that the application of a window function is typically necessary to obtain maximum dynamic range for FFT measurements The discrete Fourier Transform calculated by SR1 calc...

Страница 151: ...urements For most measurements with SR1 the Rife Vincent 4 term or the Blackman Harris window are the best windows to use The BlackmanHarris window is a proprietary improved version of the traditional...

Страница 152: ...spectrum considerably DC Correction Small amounts of DC in the FFT time record can be removed using the DC Correction control Selecting Average will subtract the average value of each time record from...

Страница 153: ...is changed so that the filter has unity gain at 2 kHz instead of 1 kHz Note that the spectral weighting selected with this option is done in the the DSP after FFT computation the filtering does not af...

Страница 154: ...s control the width of the raised cosine window that smooths the transitions to the selected portion of the impulse reponse Some experimentation may be necessary to find the settings that produce the...

Страница 155: ...r makes one shot frequency response measurements using the chirp source even easier it s not necessary to store a reference input curve for later normalization as is the case with FFT1 because the FFT...

Страница 156: ...SR1 Operation Manual 156 2014 Stanford Research Systems Passband Group Delay of Elliptical Filter...

Страница 157: ...er Panel Fundamental Frequency Selection The THD Analyzer computes the power in two sets of harmonics both relative to the same fundamental frequency The fundamental can either be a fixed frequency or...

Страница 158: ...s frequency selective correctly displays the ration of the sum of the harmonics to the fundamental amplitude The only exception to this is when the THD analyzer source is set to Other Analyzer and the...

Страница 159: ...sed for noise measurements associated with voice transmission telecommunications CCITT The CCITT weighting filter defined by ITU T Recommendation O 41 is another telecommunication noise weighting filt...

Страница 160: ...range of the input converter can be applied to harmonics rather than the fundamental To use the THD analyzer with the Time Domain Detector select the type of one of the analyzers say A0 to be TDD Set...

Страница 161: ...r combinations of the two frequencies The modern standard for DFD is IEC 60268 3 Finally DIM Dynamic Transient Intermodulation distortion also known as TIM Transient Intermodulation Distortion uses a...

Страница 162: ...ADC and DAC devices by selecting a different generator The selected generator must be using the IMD waveform for the analyzer to function properly The choice of generator waveform SMTPE CCIF or DIM d...

Страница 163: ...measurement For instance in the CCIF DFD measurment there is a second order distortion product at the sum of the input frequencies as well as the difference However the listed distortion products repr...

Страница 164: ...lications C Msg Wt The C Msg weighting filter specified in IEEE Std 743 1995 is intended to be used for noise measurements associated with voice transmission telecommunications CCITT The CCITT weighti...

Страница 165: ...T to twice the length of the stimulus signal By making the frequency resolution of the received spectrum twice the resolution of the stimulus it is ensured that all tones harmonics of tones and IMD pr...

Страница 166: ...l several conditions must be met First the MTA must be running in synchronous mode Second the analyzer must be triggered so that the analyzer s FFT time record maintains a consistent position with res...

Страница 167: ...requency limits containing IMD products up to the selected order of all tones Total Noise A B The rms sum of all noise bins between the frequency limits If Noise Analysis is enabled this is simply the...

Страница 168: ...rder of the intermodulation products that will be included in the IMD measurements Equalization The file selection box allows specification of an EQ file which is then applied as a weighting function...

Страница 169: ...s the first lowest frequency tone Relative to RMS Amplitude The absolute voltage for each measurment is divided by the RMS voltage of the entire received signal Noise Analysis The Noise Analysis check...

Страница 170: ...be directly read off using the MTA For broadcast or recorded multitone stimuli the generator trigger is obviously no longer useful as the SR1 s generator no longer has any relation to the actual occur...

Страница 171: ...fit to the histogram data and displaying it alongside the histogram Histogram Analyzer Outputs Measurement Description Time Record A B The sequence of input samples for each input channel Histogram A...

Страница 172: ...tinuum of amplitudes between 1 FFS If the sine frequency is shifted slightly to 1 kHz the histogram changes radically Now the sampling is a multiple of the signal frequency and each cycle of the sine...

Страница 173: ...ntrols determine the upper and lower voltage limit for the histogram There is no need for the limits to be symmetric Pressing autoscale automatically sets the upper and lower histogram limits to the c...

Страница 174: ...Analyzer fits a gaussian curve to the to each computed probability histogram The parameters of the gaussian fit the mean and standard deviation are displayed in the panel The graph below shows the his...

Страница 175: ...20 kHz The bin centers and shapes follow ANSI Std S1 11 2004 In the analog domain the octave analyzer always uses the Hi Resolution converter Octave Analyzer Outputs Measurement Description Octave A B...

Страница 176: ...e and 1 12 octave Octave Averaging There are two averaging selections available for the octave analyzer exponential time averaging and peak hold averaging Exponential time averaging applies and expone...

Страница 177: ...ized at a sample rate of 256 kHz providing a maximum jitter bandwidth of approximately 113 kHz Further processing is done in the DSP processor and depends on the user s selection of Time Domain or Fre...

Страница 178: ...200 mUI of added sine jitter at 10 kHz The top trace shows the averaged N 100 Power Spectrum The bottom trace is the N 100 averaged Linear Spectrum taken with the trigger enabled Note the substantial...

Страница 179: ...e selected input is not a AES EBU or consumer digital audio carrier but instead a square wave or clock signal Clock signals bypass the clock recovery PLL and are applied directly to the Jitter Demodul...

Страница 180: ...is set to Dig Fs the measurement interval is set to an integral number of samples of the detected digital audio input sample rate When the rate is set to Jitter Gen the measurement interval is set to...

Страница 181: ...unchecked only fully alias protected lines will be displayed and the bandwidths will be adjusted accordingly Total Jitter The RMS Sum control displays the total jitter found by RMS summing all the po...

Страница 182: ...has been accumulated Other Jitter Analyzer Controls Turning on Time Domain Interpolation applies band limited interpolation to the time record of the Jitter Analyzer This is useful when looking at the...

Страница 183: ...hich can substantially improve the quality of the digitized signal Digitizer Acquisition The size of the digitizer record specified in 80MHz samples is set with the Record Length control Values from 8...

Страница 184: ...Triggers on the occurrence on the C1 input of any of the error conditions listed in the table below Receive Preamble A C2 Triggers on any channel A subframe preamble X preamble on the C2 input connec...

Страница 185: ...ored in the last byte of the channel status block A CRC error occurs if these values do not match Lock An error occurs if the digital audio receiver on the given connector cannot lock to the input sig...

Страница 186: ...signal The jitter bandwidth will be 1 2 of the bit cell rate or 32 times the embedded digital audio sampling rate Because the jitter is being sampled at each bit cell transition the calculated jitter...

Страница 187: ...signal with a small offset is shown below Eye Diagram of Offset Digital Audio Carrier Another way of observing the effect of asymmetry is to examine the histogram of pulse widths For an ideal square...

Страница 188: ...he result shown below Additional Analysis Controls The Re analyze button causes the digitizer to reanalyze the current digitizer record with possibly different analysis settings without first acquirin...

Страница 189: ...width and input pulse rate For a digital audio or clock signal the input amplitude histogram is dominated by two peaks corresponding to the positive and negative voltages of the signal Typical Digital...

Страница 190: ...range is then binned into the number of bins specified in the Y Resolution control The number of points falling into each bin is then mapped into a color indicating the relative probability of that p...

Страница 191: ...rs The Displays menu offers options for creating and managing the different types of displays used by the instrument Graph Opens a new Graph on the current page Bar Chart Opens a new Bar Chart on the...

Страница 192: ...type display Sweep traces show the data from an SR1 sweep with a fixed X axis that is defined by the sweep and data values that are defined by on of the selected Sweep Data measurments Finally EQ trac...

Страница 193: ...and off in the graph The listing shows the source of the measurement in this case analyzer A1 which is configured as an FFT analyzer and the measurement in this case Power Spectrum A When a trace is...

Страница 194: ...rt type traces and measurements shown with the icon are vector measurements which will be shown on FFT type traces Clicking on any line in the Trace Listing makes that trace the active trace which con...

Страница 195: ...pressing the button the Add Measurement form is displayed showing a tree containing all currently available measurements Double clicking on a measurement creates a trace in the graph corresponding to...

Страница 196: ...and conversion to other units may be limited Lock Axes Normally each trace has its own pair of X and Y axes and each trace can be scaled separately However there are times when it is useful to be able...

Страница 197: ...g the Cursors The two cursors may be moved by grabbing them with the mouse When the mouse arrow is moved over the cursor the arrow icon changes to At this point click the mouse button and drag the cur...

Страница 198: ...against predefined upper and lower limits To create an upper or lower limit click the appropriate radio button and click on New A dialog appears allowing selection of an existing trace on which to ba...

Страница 199: ...saved limit use the button next to the the New button and select the previously saved file from the file dialog A limit can be made a single limit in which case it has no X axis and only a single Y va...

Страница 200: ...enter a specific starting and ending X values for the calculation range Pressing the Cursors button sets the starting and ending X values according to the position of the two cursors Pressing Close a...

Страница 201: ...calculated Multiply Returns a trace containing the product of the two selected input traces Equalize Returns a trace containing the input data weighted by the selected EQ file Ratio Returns a trace c...

Страница 202: ...um minimum and standard deviation The Barchart Speedbar The bar chart speedbar contains the controls necessary to configure the display The button displays the Add Measurement panel which allows selec...

Страница 203: ...ton can be configured on the bar chart settings panel to display the maximum and minimum of the observed measurement or the mean and standard deviation Finally the button toggles the display between n...

Страница 204: ...s Connecting the bar chart to a scalar measurement such as frequency is straightforward but what does it mean to connect the bar chart to an FFT for instance The answer is supplied by the selection ma...

Страница 205: ...calculated effective digital audio sampling frequency is shown at the right hand edge of the cursor bar The central portion of the display is a tab control with 4 tabs each of which displays a differ...

Страница 206: ...eft up and down The direction of translation is adjustable on the Preferences panel Zooms the active display in and out in the X and Y direction Toggles the sense of mouse zooming Shows eye diagram in...

Страница 207: ...izer data i e essentially an oscilloscope display of the input signal The jitter vs time trace shows the jitter amplitude calculated by the digitizer as a function of time Jitter amplitude may be disp...

Страница 208: ...shown in yellow to indicate that insufficient data is available for an accurate jitter FFT spectrum Probability Tab The probability tab shows the histograms for input amplitude jitter amplitude pulse...

Страница 209: ...es not link the cursor to that trace Checking Lock X locks the X value of the two cursors to the same value so that differences between any of the envelopes can be read off directly on the cursor disp...

Страница 210: ...r Limit can be made to be symmetric around the center of the eye opening by checking the Mirror Left Right box on the Inner Upper Limit tab Arbitrarily complex limit shapes can be created for the Inne...

Страница 211: ...x can be quickly scaled up or down Limit settings can be saved to disk and recalled with the Load and Save buttons on the Eye Limits panel When Eye Limit Testing is enabled the text on the Limits butt...

Страница 212: ...es Load Displays Recalls displays saved with either the Save All Displays main menu selection or with the Save button at the top of the graph speedbar Recalled displays are placed on the same page and...

Страница 213: ...The Tools menu options are Preferences Panel Opens the SR1 User Preferences panel Events Panel Opens the SR1 Events panel Links SR1 events with user configurable actions Switcher Configuration Opens...

Страница 214: ...cted SR1 will load this configuration file ensuring that the instrument starts up in the same state that it was turned off in The Autosave file can also be used to recreate the instrument s state in t...

Страница 215: ...ect the sense of the Zoom and Translate controls on both the graph and digitizer graph displays Depending on which feels more natural the left arrow can be selected to move either the data to the left...

Страница 216: ...h the X axis in Hz and the Y axis in Vrms Selecting Last Used means that SR1 will use the most recent user units for the particular type of trace Screen Size When equipped with the optional XGA displa...

Страница 217: ...be sent with the exact case specified in the SR1 Remote Programming Reference Parse Absolute When checked SR1 requires that a full path specifier be sent with each command Un checked the object refere...

Страница 218: ...ctually connected to the rear panel connector The other serial port options such as Baud Rate Data bits etc should be set according to the device that will be communicating with SR1 Checking the On bo...

Страница 219: ...s As an example to allow only a specific range of IP addresses to connect to SR1 one would specify in the denied list and the required allowed address range in the allowed range Check Denied List Firs...

Страница 220: ...vent description enables logging of the event to a text file The Tone control allows selection of an audio tone which is played when the selected event occurs The ellipsis button to the right brings u...

Страница 221: ...ofessional channel status CSA Byte0 4 Change Channel status is sent in both consumer and professional formats in 23 byte blocks SR1 allows up to 5 bytes to be watched i e any change in the received ch...

Страница 222: ...fails on any digitizer display on which it is enabled The COM event fired by this event includes an argument identifying the particular digitizer display which triggered the event Instrument Keypad Oc...

Страница 223: ...Sweep Done when it is run When this script is associated with the Sweep Finished event the panel looks like Now each time a sweep is finished the swp2 vbs script will run and the message Sweep Done wi...

Страница 224: ...d To enable firing of the Sweep Finished COM event configure the event panel as shown below More details on scripting can be found in the scripting section of this manual Using Events with scripts giv...

Страница 225: ...tored by the events system There are 5 events for channel A CSA Byte0 4 Change and 5 events for channel B CSB Byte0 4 Change Each event is associated with one of the bytes in the received channel stat...

Страница 226: ...irst the switcher network must be configured which involves informing SR1 about the number and type of switchers and how they will be controlled as well as using the web based control interface of the...

Страница 227: ...the switch whose chain address matches the destination of the command See the SR10 11 12 manual for details on how to set the chain address and how to setup switches in a daisy chain configuration If...

Страница 228: ...connector on that switch box In this output switch example output A is connected to connectors 1 2 and 3 and output B is connected to connectors 4 5 and 6 Double clicking on the one of the connectors...

Страница 229: ...on a switch displays the switch options submenu Delete deletes the selected switch from the configuration Reset resets all connectors to their default positions no connection Identify causes relays to...

Страница 230: ...not needed for normal operation of SR1 During normal operation of the instrument all the status indicators for all of the boards should display green Should a red indicator appear indicating a problem...

Страница 231: ...twork Setup Set the instrument s IP address Network Places Display a list of files folders and computers on the network Map Network Drive Map a network location to a driver letter Remove Network Drive...

Страница 232: ...Obtain an IP address automatically Otherwise enter the IP address subnet mask gateway and DNS information manually If none of this makes any sense contact your network administrator for the correct se...

Страница 233: ...n the network Enter a drive letter name and browse the network to the desired folder If Reconnect at logon is checked the mapping will be made permanent Press Finish to confirm the drive mapping 2 6 5...

Страница 234: ...5 Share SR1 Selecting Share SR1 allows sharing of the user folder and its subfolders on the SR1 hard disk with other network users The user folder contains subfolders in which configuration files EQ f...

Страница 235: ...SR1 Operation 235 2014 Stanford Research Systems Click Share this folder to enable sharing of the folder Use the Permissions button to set up a list of network users who will be allowed to access SR1...

Страница 236: ...shutting off the display and hard drive Date Time Allows setting of the internal clock Virtual Keyboard Brings up the virtual keyboard for text entry without a physical keyboard Update SR1 Updates SR1...

Страница 237: ...removing it Select the drive to be shut down and press Eject before removing the drive 2 6 6 3 Power Options Selecting Power Options allows setting the idle time interval before SR1 s computer shuts...

Страница 238: ...ionality of a PC keyboard using only the mouse Use the virtual keyboard for text entry e g filenames in situations where SR1 is not connected to a PC keyboard The virtual keyboard can be selected via...

Страница 239: ...nscreen directions The update server will determine if the installed firmware version is the most recent and if necessary download and install all required files to update the firmware If the instrume...

Страница 240: ...from the Help menu After determining whether a more recent firmware version exists download the appropriate patch from the website and place the file on a USB drive connected to SR1 To execute the pat...

Страница 241: ...programs written in Visual Basic Microsoft Office and other COM enabled languages Local Automation or scripting refers to control of the instrument via scripts executed locally on the instrument Scrip...

Страница 242: ...eceived over the serial port RS 232 are shown in green Commands which cannot be parsed by SR1 are underlined to indicate an error Interface messages such as Local or Device Clear are placed in angle b...

Страница 243: ...l VBScript JScript Bible published by Wiley All examples in this manual will be shown in VBscript The scripting window has several sections At the top is a speedbar providing fast access to commonly u...

Страница 244: ...speedbar Stops Scripts Events Disables trapping of any events which have been set up in the current script This button is also found on the main SR1 speedbar SR1 Basic Interface Window The right hand...

Страница 245: ...tions exist in the SR1 internal scripting environment To specifiy these enumerations in VisualBasic MS Office or other scripting environments they must be referred to as SR1 enumtype enum e g SR1 HRSR...

Страница 246: ...ce ID would be modified to Call SR1 Graph graphId LoadTrace C myTraceFile xml The same syntax applies to actions with no return value Call SR1 Displays Graph graphId AutoScaleX Input and Output with S...

Страница 247: ...ancel Proceed 10 creates the window The function returns 1 if OK is pressed 0 if Cancel is pressed or the window is closed and 1 if the window times out UserChoice The UserChoice function displays a w...

Страница 248: ...or C in the example If the window times out the string timedout is returned If the user presses Cancel the string cancelled is returned UserChoiceMulti The UserChoiceMulti function also lets the user...

Страница 249: ...gs x SR1 Instrument UserLoadFile Select File 200 The return value is the full path extended filename In the example above the return value was C Program Files SR1 Audio Analyzer user config InterfaceF...

Страница 250: ...ting OpenScriptLogFormwID Opens a script logging window and returns a formID for the opened window See the SR1 Basic manual for more information on formIDs SC1 Scripting CloseScriptLogForm formId Clos...

Страница 251: ...ing the VBScipt err raise function call err raise errNo int errorSource string errorDescription string The SR1 Basic Interface includes a built in flag SR1 Scripting Terminate which is set true when t...

Страница 252: ...or all subsequent keypresses menu selections panel entries etc will then be incorporated into the script window This lets you do most of the programming by simply making a measurement normally on the...

Страница 253: ...basic format for the tests whether the inputs and outputs are analog or digital the bandwidth of the measurement mono or stero etc Based on these settings each measurement panel then configures the i...

Страница 254: ...omains do not need to be the same i e cross domain measurements may be made Next select the number of input and output channels and the connector BNC XLR or for digital audio signals Optical for the i...

Страница 255: ...ital inputs The number of inputs and outputs and the connectors used are specified in the Setup Panel Generator Configuration The output waveform is set to either Sine or Low Distortion Sine as specif...

Страница 256: ...e controls means In general specifying a smaller precision window and larger value for nPoints will decrease the noise and glitches in the sweep at the expense of increasing the time required for the...

Страница 257: ...connectors used are specified in the Setup Panel Generator Configuration The output waveform is set to either Sine or Low Distortion Sine as specified in the panel The amplitude and frequency of the...

Страница 258: ...SR1 Operation Manual 258 2014 Stanford Research Systems...

Страница 259: ...ree run operation the amplitude and frequency of the generator is set to the frequency and level in the start column of the panel For swept operation the frequency is swept from the start to stop valu...

Страница 260: ...e controls means In general specifying a smaller precision window and larger value for nPoints will decrease the noise and glitches in the sweep at the expense of increasing the time required for the...

Страница 261: ...ut 90 dB use the Low Distortion sine For free run operation the amplitude and frequency of the generator is set to the frequency and level in the start column of the panel For swept operation the freq...

Страница 262: ...e controls means In general specifying a smaller precision window and larger value for nPoints will decrease the noise and glitches in the sweep at the expense of increasing the time required for the...

Страница 263: ...he panel For swept operation the amplitude is swept from the start to stop value with the number of steps specified Analyzer Configuration One or both analyzers depending on the number of output chann...

Страница 264: ...t it has different settling options compared to other quick measurements The only settling profile available for vector measurements is average The nPoints control in this case dictates how many FFTs...

Страница 265: ...ified in the Setup Panel Generator Configuration The output waveform is set to Sine or Low Distortion Sine For free run operation the amplitude of the generator is set to the value in the start column...

Страница 266: ...armonic amplitude as a function of harmonic number For distortion FFT a graph is created showing the spectrum of the EUT output with the fundamental removed Sweep Configuration For THD analysis a grap...

Страница 267: ...center frequency is set to the specified value while the difference frequency defaults to 1 kHz For DIM measurements the tone frequencies are fixed by the standard The default tone frequencies set up...

Страница 268: ...e controls means In general specifying a smaller precision window and larger value for nPoints will decrease the noise and glitches in the sweep at the expense of increasing the time required for the...

Страница 269: ...Low Distortion Sine as specified in the panel For free run operation the amplitude and frequency of the generator is set to the frequency and level in the start column of the panel For swept operatio...

Страница 270: ...e controls means In general specifying a smaller precision window and larger value for nPoints will decrease the noise and glitches in the sweep at the expense of increasing the time required for the...

Страница 271: ...ted stimulus waveform the generator is configured with either a sine or FFT chirp waveform Analyzer Configuration If a sine stimulus is selected the A0 and A1 analyzers are configured as Time Domain D...

Страница 272: ...SR1 Operation Manual 272 2014 Stanford Research Systems on the amplitude sweep...

Страница 273: ...tion The output waveform is set to the FFT Chrip waveform For free run operation the amplitude the generator is set to the frequency and level in the start column of the panel For swept operation the...

Страница 274: ...SR1 Operation Manual 274 2014 Stanford Research Systems group delay traces are added for each amplitude setting in the sweep...

Страница 275: ...e the results are accumulated in a formatted report The report includes a header page which details the setup configuration entered in the quick measurement setup panel Subsequent pages give informati...

Страница 276: ...y the report after measurements have been made select Report from the Quick Measurements menu The report preview window includes options for page navigation zooming and scaling printing and exporting...

Страница 277: ...formed sequentially The measurement results for each selected measurement are accumulated in a report To clear the report in preparation for a new round of measurements press Clear Report To include a...

Страница 278: ...timulus signal and the domain of the analysis signal as follows Analog Analog Measurement setups entirely in the Analog Domain Analog Digital Measurement setups with an analog stimulus and a digital r...

Страница 279: ...frequency response sweep The Hi resolution converter is selected for maximum dynamic range The Time Domain Detector is selected for the A0 analyzer The Analog Generator is loaded with a sine waveform...

Страница 280: ...s 1 kHz This should be adjusted as needed The settling parameters can be adjusted to fit the noise levels of the signals being measured The bandwidth of TDD can be adjusted to suit the measurement req...

Страница 281: ...adjusted to suit the noise level of your signal The FFT resolution is defaulted to 2k points this can be adjusted Frequency Response This setup configures SR1 for a stereo audio band frequency respons...

Страница 282: ...et to Time Domain Detector in order to measure THD N of both channels A low distortion 1 Vrms sine waveform is setup with an frequency sweep range of 20 Hz to 20 kHz in 22 logarithmic steps Page 2 dis...

Страница 283: ...r signal The FFT resolution is defaulted to 4k points adjust this to obtain the proper balance of update rate vs frequency resolution Frequency Response This setup configures SR1 for a stereo audio ba...

Страница 284: ...of the A and B channel results What you ll need to configure The default frequency is 1 kHz This should be adjusted as needed The settling parameters can be adjusted to fit the noise levels of the sig...

Страница 285: ...an be adjusted Frequency Response This setup configures SR1 for a stereo audio band frequency response sweep The Time Domain Detector is selected for the A0 analyzer The Digital Generator is loaded wi...

Страница 286: ...N A low distortion 1 FFS sine waveform is setup with an frequency sweep range of 20 Hz to 20 kHz in 22 logarithmic steps Page 2 displays a graph of the A and B channel THD N vs Frequency What you ll...

Страница 287: ...lts What you ll need to configure Adjust the amplitude of the jitter chirp on the Digital IO Panel Jitter Sweep This setup measures jitter amplitude vs frequency using a sweep The frequency of a jitte...

Страница 288: ...e instrument as opposed to demo mode the serial number of the instrument is also displayed Always record the instrument software version and serial number before contacting Stanford Research Systems f...

Страница 289: ...SR1 Operation 289 2014 Stanford Research Systems...

Страница 290: ...Part III SR1 Reference Audio...

Страница 291: ...Knob Controls the volume of signals routed to the speaker and headphone using the Monitors Panel Does not control the volume of system sounds generated by the Windows operating system The Windows soun...

Страница 292: ...mouse tap in the lighter grey area at the top right hand corner of the touch pad L Digital Audio Output Section Contains connectors for digital audio output There are two pairs of connectors labeled C...

Страница 293: ...ured as a DCE transmit on pin 3 receive on pin 20 The Baud Rate Parity and Word Length are all configured on the Remote tab of the Preferences Panel To connect the SR1 to a typical PC serial port usua...

Страница 294: ...ase synchronous with the outputs from the Analog Generator These signals are only meaningful if the Analog Generator Waveform has periodic zero crossings i e is not noise K Burst Monitor Out Chs A and...

Страница 295: ...of the sample Thus it is a squarewave with the same frequency as the digital audio sampling frequency This signal is unaffected by any jitter selected on the impairment tab of the Digital I O panel Q...

Страница 296: ...Ground Unbalanced Float Common Mode Test Source Impedance 50 150 600 balanced 25 75 600 unbalanced Max Power 600 load Balanced 30 5 dBm Unbalanced 24 9 dBm Float Voltage 40 V Crosstalk 10 Hz to 20 kH...

Страница 297: ...z BW Hi Res DAC Fs 128 kHz 1 kHz 4Vrms 99 dB 22 kHz BW 20 Hz to 20 kHz 98 dB 1 V 22 kHz BW 10 Hz to 57 6 kHz 96 5 dB 1 4 V 57 6 kHz BW Hi Res DAC Fs 64 kHz 1 kHz 4Vrms 106 dB 22 kHz BW 20 Hz to 20 kHz...

Страница 298: ...Audio Signal Generator Digital Audio Carrier Characteristics Output Amplitude Balanced Range 16 mV to 10 24 V 110 load Accuracy 10 80 mV Unbalanced Range 4 mV to 2 55 V 75 load Accuracy 10 20 mV Outpu...

Страница 299: ...rements Polarity 10 Hz to Fs 4 frequency range Bursts All allowed waveforms Digital Test Waveforms Digital Constant Count Rotating Bits Staircase J Test Dither None triangle and rectangular probabilit...

Страница 300: ...osstalk 10 Hz to 20 kHz 140 dB 20 kHz 135 dB Hi BW ADC Type 16 bit sigma delta Sampling Frequency 512 kHz Frequency Range DC to 228 kHz Hi Resolution ADC Type 24 bit sigma delta Sampling Frequency 128...

Страница 301: ...hase Meter 0 5 accuracy f 50 Hz Analyzers Analog and Digital Audio Time Domain Analyzer Measurements Amplitude amplitude ratio THD N THD N ratio SINAD Analog Inputs Amplitude Accuracy 0 5 0 043 dB Fla...

Страница 302: ...s 20 kHz 40 kHz and 80 kHz fixed elliptical filters per AES17 High Pass Filter 4th order Butterworth 22 Hz 100 Hz and 400 Hz 20 kHz 40 kHz and 80 kHz fixed elliptical filters per AES17 Band Pass Filte...

Страница 303: ...F Gaussian fit to PDF Multitone Analyzer Level Frequency Response THD N noise THD IMD Crosstalk Digital Audio Carrier Measurements Measurements Carrier amplitude sample rate jitter amplitude jitter sp...

Страница 304: ...Reference Input Sources AES3 24 Hz to 216 kHz sine or TTL 8 kHz to 32 MHz video NTSC PAL SECAM Reference Output Format AES3 24 Hz to 216 kHz Video Out VGA output for driving external monitor Power 27...

Страница 305: ...r can be inserted in the signal chain after the Notch Bandpass filter and before the postfilter gain elements Note that the optional filters only affect Hi Bandwidth analog measurements At the current...

Страница 306: ...frequency and 6 real poles This A Weighting transfer function is represented by the EQ file shown below xml version 1 0 encoding UTF 8 DOCTYPE EQcurve SYSTEM EQcurve dtd EQcurve MetaData Source Value...

Страница 307: ...oring a list of frequencies and responses and using spline interpolation to interpolate the values at other frequency points The list of y values in the files may be either pure numbers or dB ratios A...

Страница 308: ...f frequency values and response values must be the same length When interpolating in a sampled EQ file if the required frequency is less than the value of the lowest frequency point in the list the re...

Страница 309: ...values are disregarded when outputting an arbitrary waveform only the relative magnitudes of the sample values are important To arrive at the absolute scaling SR1 first estimates any overshoot that m...

Страница 310: ...ntrol Panel from the Windows start menu 3 Double click the Display icon and choose the settings tab Click on the Advanced Button 4 Click on the S3Display tab You should see the following panel 5 Click...

Страница 311: ...m of the instrument Turn the instrument onto its left side and remove the 6 screws that attach the feet to the bottom of the instrument Rotate the instrument back onto its bottom 3 Remove the front tw...

Страница 312: ...g Colors 35 Digital Colors 35 Common Analyzer Features 108 Common Mode Sine 79 Computer Functions 236 Confidence 79 Configuration Files 28 29 30 31 Constant Offset 43 Controls Unit Display 13 Unit Ent...

Страница 313: ...xternal Reference Input 293 External Sweeps 94 External Trigger Input 293 External Video Connector 293 Eye Diagrams 209 F FFT 127 141 FFT Dual Ch 141 FFT Analyzer 1 Ch 127 FFT Chirp 43 62 FFT1 Analyze...

Страница 314: ...57 Headphone 100 Headphone Jack 291 Help 288 Hi Bandwdith 108 Hi Res Converter 76 Hi Resolution 108 Histogram Analyzer 171 Averaging 173 Bins 173 Fit 174 Measurements 171 Panel 172 Range 173 Sample Ra...

Страница 315: ...0 Validation 170 N Network Drives 233 Network Places 232 Network Setup 231 Networking Options 231 Noise 43 46 62 Normal Mode Noise 79 O Octave Anallyzer Panel 175 Octave Analyzer Averaging 176 Mode Se...

Страница 316: ...99 Sharing SR1 234 Signal to Noise 255 Sine 62 Sine Low Distortion 43 Sine Normal 43 SMPTE DIN 62 161 267 SNR 255 Software Updates 238 Speaker 100 Specifications 296 Square Wave 43 62 SR1 Basic 244 A...

Страница 317: ...Validity 79 VBScript 243 Video Reference 105 Video Reference Input 293 Virtual Keyboard 238 Virtual Keypad 13 Visual Basic 243 Volume Knob 291 VXI 11 218 241 W Weighting Filters 164 X XLR Connector 79...

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