manualshive.com logo in svg

Quantifi Photonics IQTX 1100 Series, User Manual, Page: 34 / 75

Share
Download
Quantifi Photonics IQTX 1100 Series User Manual Download Page 34

Coherent Modulation Transmitter | IQTX 

Quantifi Photonics Ltd. 

Version 

1.04

 

34 

An important point to note is that when a frequency value is specified by the user, if the value lies in 

between any two adjacent GRID points, and can be tuned to, it will tune up from the lower GRID point 
value. The laser will never tune down from a GRID point value to reach the final point. 

In the example below, the user sets the output frequency to 193.414489 THz, with a GRID spacing of 1 

GHz. The laser first tunes to the closest GRID point below the intended frequency value (193.414 THz), and 
then uses FINE TUNE OFFSET to fine tune by 489 MHz up to the final set point  

 

 

 

9.6.3

 

Frequency fine tuning 

Another option a user has is to use the FREQUENCY:FINE tuning functionality to tune the laser by       
+/- 6 GHz around the set GRID point value.  

Commands 

Description 

SOUR1:CHAN1:GRID

 1 GHz 

SOUR1:CHAN1:FREQ

 193.414489 THz 

 

 

-

 

Query the frequency fine setting. 

-

 

Fine tune the frequency by +50 MHz from the 
current GRID point (193.414 THz). 

-

 

Query the current frequency setting 

SOUR1:CHAN1:FREQ:FINE?

 -> 489 MHz 

SOUR1:CHAN1:FREQ:FINE

 50 MHz 

 

SOUR1:CHAN1:FREQ?

 -> 193.414050 THz

 

It should be noted that if the GRID spacing has been set to a value larger than 6 GHz, then there will be a 
range of values that sit between adjacent frequency grid points which will be impossible to tune to, using 
the fine tuning functionality.  

In the example below, the GRID spacing has been set to 20 GHz, meaning that between any two 
adjacent GRID points, there lies an 8 GHz region that is non-accessible. If tunability is a primary concern, 

it is suggested that the user set the GRID spacing to be <= 6 GHz.  

Summary of Contents for IQTX 1100 Series

Page 1: ......

Page 2: ...nder any patent rights of Quantifi Photonics The information contained in this publication is subject to change without notice Trademarks Quantifi Photonics trademarks have been identified as such However the presence or absence of such identification does not affect the legal status of any trademark LabVIEW MATLAB and Python are trademarks of National Instruments The MathWorks Inc and the Python ...

Page 3: ...p IQTX and powering ON 15 Setting up IQTX and powering ON 15 Setting up IQTX for single polarization IQTX 1100 Series models only 16 Setting up IQTX for dual polarization 17 6 3 1 IQTX 1100 Series Emulated Dual Polarization 17 6 3 2 IQTX 1200 Series Full Dual Polarization 17 7 Installing software 18 Installing Cohesion Operator software package on client computer s 18 Checking instrument firmware ...

Page 4: ... 40 Powering on off the IQTX instrument 40 LCD control touch screen Graphical User Interface GUI 40 10 2 1 Main display 40 10 2 2 Setting laser channel parameter values 40 10 2 3 Toggling the laser channel on off 41 10 2 4 Setting modulation channel parameters 41 10 2 5 Settings menu 41 10 2 6 Navigation within the settings menu 42 10 2 7 Device information 42 10 2 8 Ethernet connectivity configur...

Page 5: ...ple 66 MATLAB code example 67 13 Example QPSK configuration procedures 68 Set the laser frequency and power 68 Setting RF delay for IQ Skew optional certain models only 68 13 2 1 I Q RF delay adjustment 68 13 2 2 IQ skew 68 Modulator adjustments 69 13 3 1 Modulator bias I and bias Q 69 13 3 2 I Q optical phase offset 70 14 Measurement definitions 71 IQ RF imbalance 71 Error vector 71 15 Maintenanc...

Page 6: ...s are met and understood Indicates a potentially hazardous situation which if not avoided may result in minor or moderate injury Do not proceed unless the required conditions are met and understood Indicates a potentially hazardous situation which if not avoided may result in component damage Do not proceed unless the required conditions are met and understood Refers to information about this prod...

Page 7: ...tected at all times The use of controls adjustments and procedures other than those specified herein may result in exposure to hazardous situations involving optical radiation FDA Certification This IQTX complies with 21 CFR 1040 10 and 1040 11 except for deviations pursuant to laser notice no 50 dated June 24 2007 Electrostatic discharge precautions The IQTX is sensitive to electrostatic discharg...

Page 8: ... in an industrial environment There may be potential difficulties in ensuring electromagnetic compatibility in other environments due to conducted as well as radiated disturbances Wherever the symbol is printed on the unit refer to the instructions provided in the device documentation for related safety information Ensure that the required conditions are met and understood before using the product...

Page 9: ... polarization coherent modulation format leading to a significant system cost reduction This approach is widely used in R D environments where there is no need to have independent data pattern on all four tributaries The IQTX comes with a narrow linewidth high power tunable internal laser which can conveniently be controlled using the touchscreen LCD or remotely from a PC using the web based softw...

Page 10: ... 5 RF signal X Pol I input 6 RF signal X Pol Q input 7 RF signal Y Pol I input 8 RF signal Y Pol Q input 9 LCD screen 10 Connector type information Rear panel 11 USB connection to PC 12 Ventilation fans DO NOT OBSTRUCT 13 Ethernet port 14 Chassis grounding screw 15 Mains power on off isolation switch 16 AC power 100 240 V 50 60 Hz 70 W Max You must use the IEC cable that has been supplied by Quant...

Page 11: ...t errors Where possible avoid frequent connections disconnections of the RF Coax array on the front panel as it will gradually wear each time the harness is connected or disconnected Do not bend or deform rigid cables as this will cause damage Use ESD protection at all times especially when handling RF input output connectors Making a connection When making a connection Wear a grounded wrist strap...

Page 12: ... avoids damage due to over or under tightening connections It significantly improves measurement accuracy and repeatability at mm wave frequencies avoids signal failure and extends connector life When using a torque wrench Make sure the torque wrench is set to the correct torque setting refer 4 5 Torque settings Position torque wrench and a second wrench to hold the device or cable within 90 of ea...

Page 13: ...s Ltd Version 1 04 13 Torque settings Wrench type Torque settings 1 0 mm 4 in lb 45 N cm 1 85 mm 8 in lb 90 N cm 2 4 mm 8 in lb 90 N cm NMD 2 4 mm 8 in lb 90 N cm 2 92 mm 8 in lb 90 N cm 3 5 mm 8 in lb 90 N cm NMD 3 5 mm 8 in lb 90 N cm SMA 5 in lb 56 N cm ...

Page 14: ...ailure to do so will result in permanent damage to the connectors and degradation of future measurements Cleaning and connecting optical fibers To connect the fiber optic cable to the port 1 Inspect the fiber using a fiber inspection microscope If the fiber is clean proceed to connect it to the port step 6 2 If the fiber is dirty clean it as detailed below 3 Gently wipe the fiber end with a lint f...

Page 15: ...itive to ESD Ensure you are wearing a grounded wrist strap at all times when handling the instrument to prevent damage from electrostatic discharge Do not remove the IQTX instrument from the antistatic packaging until required Take care not to handle the optical connectors on the IQTX instrument as once they are exposed to skin contact this may leave corrosive residue and damage the connector You ...

Page 16: ... own narrow linewidth Laser with a PM output using a PM patch cord linewidth needs to be less than 500 kHz 3 Use the output port of the modulator for a linearly polarized single polarization signal The power level going into the modulator Laser input port must not exceed the Max Input power specified for the model STEP 4 Once all connections are completed turn ON the isolation switch located next ...

Page 17: ...nect the Single Polarization SIGNAL OUT to the Dual Polarization SIGNAL IN using a PMF patch cord to generate the Y pol modulation signal 2 The dual polarization modulated signal generated from the input RF pattern is then output from the optical port labelled Dual Polarization SIGNAL OUT 6 3 2 IQTX 1200 Series Full Dual Polarization The IQTX 1200 Series instrument can generate optical signals fro...

Page 18: ...uter recommended Save your work and close all programs If using the USB media device insert it on the computer Double click CohesionOperator version exe and follow the prompts A Windows Security Alert may prompt you to allow network access We recommend that you allow access to both private and public networks to enable any network configuration The installation wizard will install required drivers...

Page 19: ...Coherent Modulation Transmitter IQTX Quantifi Photonics Ltd Version 1 04 19 ...

Page 20: ...other product information You can check the details of an instrument in Cohesion Operator or in CohesionUI In Cohesion Operator 1 Select the instrument 2 Click Connect 3 Current instrument information will be displayed In CohesionUI 1 Select INFO on the menu 2 Instrument information will be displayed in the info panel ...

Page 21: ...ct the instrument by entering its IP address or by selecting it from the Discovery drop down list 4 To confirm that you have selected the correct instrument click Connect This will retrieve instrument information with Installed Package showing the current firmware version 5 In Package click the Browse button navigate to the previously downloaded firmware package and select it 6 Click Upgrade The i...

Page 22: ...ftware packages refer to the user manual that came with your instrument To restore factory settings 1 Open the Cohesion Operator for example by double clicking the Cohesion Operator desktop icon 2 Select the instrument by entering its IP address or by selecting it from the Discovery drop down list 3 optional Retrieve instrument information including current firmware versions by clicking Connect 4 ...

Page 23: ...sion Operator software package on client computer s Accessing CohesionUI Open CohesionUI from Cohesion Operator refer 7 1 or launch Google Chrome or Microsoft Edge on a computer and type in the IQTX IP address into the address bar of the browser e g 10 10 10 89 The IP address of the IQTX is displayed on the LCD screen on the front of the instrument for both access via USB or Ethernet When both Eth...

Page 24: ...ial number and firmware versions Setting values In CohesionUI you can manually set values for parameters where applicable To set a value 1 Click on a parameter and enter a value 2 Confirm the value 3 Alternatively you can use and to increase or decrease the value You can edit the step size in the SETTINGS menu refer 8 5 Managing CohesionUI settings To set a value to a pre defined value for example...

Page 25: ...s on setting a value refer 8 3 Setting values Managing CohesionUI settings On the SETTINGS page you can configure CohesionUI settings and unit preferences Step size refers to the amount by which the attenuation frequency or power increases decreases when the or button is clicked To view all settings and unit preferences and adjust as required 1 Click SETTINGS 2 Change settings or unit preferences ...

Page 26: ...Coherent Modulation Transmitter IQTX Quantifi Photonics Ltd Version 1 04 26 To adjust unit preferences one at a time 1 Hover over SETTINGS 2 Select a unit from the dropdown for example the power unit ...

Page 27: ...is is a static address set during instrument calibration If necessary you can change this address Typing the default IP address in a supported web browser will open the CohesionUI page for the instrument The network settings controls are available in the SETTINGS page The value in the 3rd octet of the IP address can be changed to any available value It is important to make sure that any other inst...

Page 28: ...can be changed to a static method where the IQTX instrument will always have the same IP address over Ethernet Typing in a valid IP address and Subnet mask and then clicking APPLY will save the IP address into the settings of the instrument To test if the IP addressing has worked power OFF the instrument and disconnect the USB cable Turn the unit back ON and once it has finished booting check the ...

Page 29: ...he INFO button will display an information panel on the right hand side of the page Information such as the chassis operation mode manufacturer model and serial number of the chassis CohesionUI version number and the version of CohesionSCPI service running on the chassis is displayed in this panel ...

Page 30: ...ONTROL Control mode and bias values of the modulation channels and laser settings ADVANCED Control modulator dither size values and interval HISTORY Review modulator bias values vs time error history plots SCANS Review modulator biases power vs biases voltage plots Setting the modulation channels mode The IQTX modulation channels can operate in AUTO mode default or MANUAL mode To set the mode for ...

Page 31: ...e IQTX instrument is displayed in the CONTROL tab on the top middle ribbon of the screen Initiating a DC bias scan You can initiate a new DC bias scan after the initial power up of the unit and when you require a new scan of the current Min Min Quad bias points To initiate the scan 1 Click FORCE CALIBRATE in the CONTROL tab or in the HISTORY tab 2 During the re calibration process the color strip ...

Page 32: ...cy up to 6 GHz around the closest GRID point with 1 MHz resolution Set query the laser output wavelength value with 0 01 pm resolution SOURce n CHANnel m FREQuency FINE SOURce n CHANnel m WAVelength All lasers with firmware versions equal to or higher than 1 30 will support full spectral tunability down to the minimum resolution of 1 MHz 0 01 pm Older versions only support full tuning down to the ...

Page 33: ...If the intended value is above the minimum resolution of 1 MHz then the value will be directly set If the intended value is specified to below the minimum resolution then the outstanding value will be truncated highlighted below in red Intended user frequency value Accepted frequency value Applied frequency value 193 41448 THz 193 4144800 THz 193 414480 THz 193 4144890 THz 193 414489 THz 193 41448...

Page 34: ...the FREQUENCY FINE tuning functionality to tune the laser by 6 GHz around the set GRID point value Commands Description SOUR1 CHAN1 GRID 1 GHz SOUR1 CHAN1 FREQ 193 414489 THz Query the frequency fine setting Fine tune the frequency by 50 MHz from the current GRID point 193 414 THz Query the current frequency setting SOUR1 CHAN1 FREQ FINE 489 MHz SOUR1 CHAN1 FREQ FINE 50 MHz SOUR1 CHAN1 FREQ 193 41...

Page 35: ...I for each modulator bias can be set in the ADVANCED tab by clicking the parameter field or by using the and control buttons to increase or decrease the value by a set amount The step size is set to 2 Alternatively the DITHER SIZE can also be set to the MIN and MAX value by clicking the dropdown in the name of the parameter Increasing the dither size will lead to a more accurate bias optimization ...

Page 36: ...ue for each modulator can be set in the ADVANCED tab by clicking the parameter field or by using the and control buttons to increase or decrease the value by a set amount Alternatively the DITHER INTERVAL can also be set to the MIN and MAX value by clicking the dropdown in the name of the parameter The dither interval determines how frequently the bias control dither is applied Lower dither interv...

Page 37: ... The polarization X or Y and the modulator biases All I Q P can be selected and filtered by clicking the drop down lists above the plots area The plots can be zoomed to show a specific section of the analysis by clicking and dragging the desired area with the cursor To reset the zoom click the Autoscale button or double click on the plot area To download a plot as a PNG file click the Download plo...

Page 38: ... power vs biases voltage plots To review modulator biases power vs biases voltage plots click the SCANS tab The polarization X or Y and the modulator biases All I Q P can be selected and filtered by clicking the drop down lists above the plots area The plots can be zoomed to show a specific section of the analysis by clicking and dragging the desired area with the cursor To reset the zoom click th...

Page 39: ...Coherent Modulation Transmitter IQTX Quantifi Photonics Ltd Version 1 04 39 To download a plot as a PNG file click the Download plot as a png button ...

Page 40: ...aser channels and their frequency and power values along with the option to power on off a specific laser channel and to adjust the settings of the instrument The IQTX IP address is displayed irrespective of the operation mode access over USB or Ethernet When both USB and Ethernet cables are connected to the instrument the IP displayed on the LCD will alternate between USB and Ethernet IP addresse...

Page 41: ...l parameters Clicking the IQABC row in the main display will open the configuration panel of the modulation channels Select a channel and set the mode to AUTO or MANUAL In manual mode you can set the BIAS value for the channel 10 2 5 Settings menu The settings menu is used to configure the IQTX instrument settings and unit preferences These controls can be accessed by clicking the settings button ...

Page 42: ... addressing method select the DHCP ON button The DHCP will automatically assign the instrument an IP address To set a static IP address over the Ethernet select the DHCP OFF button and set the IP address and the Subnet mask by clicking on the IP SUBNET filed and typing in a valid value To save and apply the changes click the tick mark To test if the IP addressing has worked power OFF the instrumen...

Page 43: ... the Settings menu 10 2 11 Unit settings To access the unit settings click on the UNITS tab in the menu Set the preferred measuring unit of the spectrum and the power by selecting the desired unit type next to the value 10 2 12 Step size settings To access the step size settings click on the STEP SIZE tab in the menu Step size refers to the amount by which the wavelength power and additional value...

Page 44: ...Coherent Modulation Transmitter IQTX Quantifi Photonics Ltd Version 1 04 44 ...

Page 45: ...space character 0116 0916 0B16 2016 value Is numerical data an integer a decimal exponential 10e 9 or 5 8e6 or string VALUE1 VALUE2 A parameter choice The separates the unique parameters available only one of the choices can be used In the example either the input parameter VALUE1 or VALUE2 can be used but not both Some commands may have more than two choices available This parameter can be omitte...

Page 46: ... Status Byte Register STB To ignore any of the events detected and set in the SESR set the corresponding bit within the SESR Mask to 0 The STB can then be queried and the value of the ESB can be used to determine service request requirements based on the SESR Mask applied The default bit values within the SESR Mask are all 0 11 2 3 Status Byte Register The Status Byte Register STB is built from al...

Page 47: ...n IDN Query the chassis identification OPC Query the Operation Complete Status OPT Query the modules managed by the CohesionSCPI service ESR Query the Standard Event Status Register ESE Set or query the Standard Event Status Enable ReSeT Reset command TeST Query a Self Test Common system command descriptions Command IDN Syntax IDN Description Query the chassis identification Parameters No paramete...

Page 48: ... 32 4 Execution Error 16 3 Device dependent Error 8 2 Not used 0 1 Not used 0 0 LSB Operation Complete 1 Example ESR 8 It is recommended to use the ESR command query after every command that is sent to the device The ESR query will be able to catch Device dependent Error the device is reporting an error in operation Execution Error SCPI was unable to execute the given command Command Error SCPI wa...

Page 49: ...T Syntax ReSeT Description The reset command will clear all current configuration settings and restart the IQTX Effectively power cycling the instrument and restarting with stored configuration settings Parameters No parameters Response No response Example RST Command TeST Syntax TeST Description Perform a Self test query on the IQTransmitter Parameters No parameters Response Integer bit value 0 t...

Page 50: ...ion channel auto bias state BIAS Set or query the modulation channel DC bias voltage LOCK Query whether the bias is locked to its optimal position PDPower Set or query the output power of the unit mW CALibrate Force or query the recalibration of the auto bias control system OUTPut CHANnel m STATE Set or query the optical output state of the laser SOURce CHANnel m POWer Set or query the laser outpu...

Page 51: ...rs Response The decimal version number of SCPI compliance Example SYSTEM VERS 1990 0 11 6 2 Slot commands Command ABC OPC Syntax ABC OPC Description Query the status of the Operation Complete bit Parameters No parameters Response 1 is returned if the module is ready to execute a new operation 0 is returned if the module is busy Example ABC OPC 1 Command ABC OPTions Syntax ABC OPTions Description Q...

Page 52: ...tax ABC XI XQ XP YI YQ YP BIAS wsp MIN MAX DEF value Description Set the modulator channel bias voltage Parameters MIN Set to the minimum programmable value MAX Set to the maximum programmable value DEF Set to the default programmable value value Sets to the user value V is default The valid range is 14 0 to 24 0 Response No response Example ABC XI BIAS 1 Command ABC XI XQ XP YI YQ YP BIAS Syntax ...

Page 53: ... POWER number of points N dcbias x axis for all power1 powerN ERROR number of points N dcbias x axis for all error1 errorN PHASE number of points N dcbias x axis for all phase1 phaseN FULL number of points N dcbias x axis for all power1 powerN error1 errorN phase1 phaseN UNIT The scan measurement unit Example ABC1 XI SCAN POWER 32 14 000000 13 125000 12 250000 11 375000 10 500000 9 625000 8 750000...

Page 54: ... value of the unit MAX Get the maximum output power value of the unit ALL Returns all of the above parameters in a comma separated string UNIT Get the output power measurement unit TIME Get the TIME UNIT Get the time measurement unit Response Returns the current output power of the unit in mW Example ABC PDP ALL 0 000 10 000 0 142 Command ABC PDPower Syntax ABC PDPower NULL Description Set the out...

Page 55: ...e vs DC Voltage scan UNIT Get the unit of the Vpi value Response Depending on the parameters the response will be a single value or a comma separated string of values Example ABC1 MODulator1 VPI POWER 3 073177 3 030208 3 753062 NAN NAN NAN Command ABC SLOWfactor Syntax ABC SLOWfactor wsp value MIN MAX DEF Description Set the optimizer timing factor Parameters Value Set the optimizer timing factor ...

Page 56: ...CHANnel m POWer wsp MIN MAX DEF SET UNIT STEP ACT ALL Description Query the power of the selected laser Parameters MIN Get the minimum programmable value MAX Get the maximum programmable value DEF Get the default programmable value SET Get the desired set value UNIT Get the measurement unit STEP Get the step size value ACT Get the current value default ALL Returns all of the above parameters Respo...

Page 57: ...e maximum programmable value DEF Set the default programmable value Response No response Example SOUR CHAN1 FREQ 1 92 THZ Command SOURce CHANnel m FREQuency Syntax SOURce CHANnel m FREQuency wsp MIN MAX DEF SET UNIT STEP ACT LOCK ALL Description Get the laser output frequency Parameters MIN Get the minimum programmable value MAX Get the maximum programmable value DEF Get the default programmable v...

Page 58: ...nse queried with the GRID command below MIN Get the minimum programmable value MAX Get the maximum programmable value DEF Get the default programmable value Response No response Example SOUR CHAN1 GRID 2 GHZ Command SOURce CHANnel m GRID Syntax SOURce CHANnel m GRID wsp MIN MAX DEF SET ALL Description Query the grid spacing Parameters MIN Get the minimum programmable value MAX Get the maximum prog...

Page 59: ... Photonics Ltd Version 1 04 59 Command SOURce CHANnel m TEMPerature Syntax SOURce CHANnel m TEMPerature Description Get the laser temperature Parameters No parameters Response Numerical temperature in degrees Celsius Example SOUR CHAN1 TEMP 26 88 ...

Page 60: ...t common error codes are 17 IO write error the command was invalid or not accepted by the instrument 15 IO timeout there was no response available before expiry of the reading wait time To open the SCPI Command Console Open the Cohesion Operator for example by double clicking the Cohesion Operator desktop icon Select the instrument by entering its IP address or by selecting it from the Discovery d...

Page 61: ...eturn identification details 3 To send a command or query to a Quantifi Photonics device Enter a command and press ENTER The device will execute the command and return an action response to the console if applicable 4 To exit the SCPI Command Console Enter q and press ENTER Example Send instrument identification query idn 5 Enter the command idn The instrument returns the requested information 6 I...

Page 62: ...s Ltd Version 1 04 62 Example Send a WRITE only command 7 Enter a command correctly for example cls The instrument executes the command there will be no action response 8 Enter the command incorrectly csl The instrument returns error code 17 IO write error ...

Page 63: ...e configuration OPT IQABC LASER 3 Query the identification information for a specific slot module MODUle2 IDN Quantifi Photonics Ltd LASER 1002 2 SC QP 987654 HW0 01 02FW0 01 32 Configuring the Laser module on the IQTX instrument 1 Set the Laser output power to 10 dBm SOURce2 CHANnel1 POWer 10 DBM 2 Set the Laser frequency to 193 4145 THz 1550nm SOURce2 CHANnel1 FREQuency 193 4145 THZ 3 Turn the L...

Page 64: ... NI MAX launch the application In the left side panel of the window click the Devices and Interfaces option A drop down of available instruments detected will show up 2 Click on Network Devices then click Add Network Devices and select VISA TCP IP Resource 3 Select Manual Entry of LAN Instrument Enter in the Hostname or IP Address The top image is an example of operating remotely the bottom image ...

Page 65: ...teps must be completed before attempting to communicate using NI VISA 1 Launch NI MAX In the left hand side menu select an Instrument from the Network Devices list 2 On the right hand side panel select Open VISA Test Panel A new window will popup Click the Input Output button from the window menu Valid commands can be entered in and their returns queried ...

Page 66: ... this with the IP of your device ip 127 0 0 1 try print connecting to ip instrument vxi11 Instrument ip print connected print checking IDN command IDN data instrument ask command print IDN data print checking OPT command OPT data instrument ask command print OPT data replace this with a valid command for your device read the programming guide section for examples command print writing a specific c...

Page 67: ...been removed from the workspace without first being closed cleanly disconnected PXIE_Chassis instrfind Type visa tcpip RsrcName TCPIP0 10 10 10 89 inst0 INSTR Tag Create the agilent VISA TCPIP object if it does not exist otherwise use the object that was found if isempty PXIE_Chassis PXIE_Chassis visa agilent TCPIP0 10 10 10 89 inst0 INSTR else fclose PXIE_Chassis PXIE_Chassis PXIE_Chassis 1 end O...

Page 68: ... certain models only 13 2 1 I Q RF delay adjustment The I Q RF delay adjustment is used to set the correct delay between the In phase I and Quadrature Q RF input signals hence reducing the IQ skew see definition below The delay will have to be calibrated to the particular hardware configuration in operation due to the internal connections combined with the lengths of the RF cables connecting the R...

Page 69: ...nt I Q is related to reducing bias error within the constellation represented by ΔI and ΔQ in section 13 3 2 I Q optical phase offset The bias offset is a measure of how far the center of the constellation is with respect to the ideal center point For QPSK and QAM modulation formats the ideal center point is 0 0 I Q It is more convenient to represent the bias errors in percentages to make it indep...

Page 70: ...e offset dial should be adjusted to align the clusters to the ideal phase relationship of 90 which is shown in Figure 26 The quadrature error is a measure of the phase error of the constellation points with respect to the ideal phase relationship between the constellation points For QPSK and QAM modulation formats the ideal phase between the constellation points is 90 The quadrature error is an av...

Page 71: ... Calculation Error vector The error vector can be separated into its two primary components Error Vector Magnitude EVM and Phase Error PE The error vector magnitude is the magnitude of the error vector which is the difference between the signal vector and the ideal reference vector It is more convenient to represent the EVM as a percentage to make it independent of the average signal power as show...

Page 72: ...product will naturally degrade over time it is important to periodically re test the product to confirm that it is working to specification All Quantifi Photonics products are calibrated during manufacture and each product is shipped to the customer with a Calibration Certificate On this certificate the calibration date as well as the next calibration due date are mentioned We recommend your produ...

Page 73: ...otonics com To accelerate the process please have information such as the name and the serial number see the product identification label as well as a description of your problem close at hand Transportation Maintain a temperature range within specifications when transporting the unit Transportation damage can occur from improper handling The following steps are recommended to minimize the possibi...

Page 74: ...r usage transportation or unauthorized modification of the product its accompanying accessories and software Exclusions Quantifi Photonics reserves the right to make changes in the design or construction of any of its products at any time without incurring obligation to make any changes whatsoever on units purchased Accessories including but not limited to fuses pilot lamps batteries and universal...

Page 75: ...1 04 ...

Reviews:

No comments