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Frequency Modulation (FM)

A modulated waveform consists of a

carrier waveform

and a

modulating

waveform

. In

, the frequency of the carrier is varied by the amplitude

of the modulating waveform. The function generator will accept

only

internal

modulating signal (no external source is available).

For more information on the fundamentals of Frequency Modulation,
refer to chapter 7, “Tutorial”.

To Select FM Modulation

•

The

annunciator turns on when

is enabled.

•

Only one modulation mode can be enabled at a time. When you
enable

, the previous modulation mode is turned off.

•

Front-Panel Operation

: Enable

before

setting up the other

modulation parameters. Press

Shift FM

to output an

waveform

using the present settings for the carrier frequency, modulating
frequency, output amplitude, and offset voltage.

•

Remote Interface Operation

: To ensure proper operation, you should

enable

after

you have set up the other modulation parameters.

FM:STATe {OFF|ON}

Chapter 3 Features and Functions
Frequency Modulation (FM)

Summary of Contents for 33120A

Page 1: ...pability Easy to use knob input Highly visible vacuum fluorescent display Instrument state storage Portable ruggedized case with non skid feet Flexible system features Four downloadable 16 000 point arbitrary waveform memories HP IB IEEE 488 interface and RS 232 interface are standard SCPI Standard Commands for Programmable Instruments compatibility Optional HP 34811A BenchLink Arb Waveform Genera...

Page 2: ...ce 1 Function Modulation keys 2 Menu operation keys 3 Waveform modify keys 4 Single Internal Trigger key Burst and Sweep only 5 Recall Store instrument state key 6 Enter Number key 7 Shift Local key 8 Enter Number units keys 2 ...

Page 3: ...de to enter a number with the appropriate units Use the knob and the arrow keys to modify the displayed number Increments the flashing digit Decrements the flashing digit Moves the flashing digit to the right Moves the flashing digit to the left Use Enter for those operations that do not require units to be specified AM Level Offset Duty and Store Recall State 3 ...

Page 4: ...TS 3 LINE EDIT 4 POINT EDIT 5 INVERT 6 SAVE AS 7 DELETE The commands enclosed in square brackets are hidden until you make a selection from the NEW ARB command to initiate a new edit session D SYStem MENU 1 OUT TERM 2 POWER ON 3 ERROR 4 TEST 5 COMMA 6 REVISION F CALibration MENU 1 SECURED 1 UNSECURED 2 CALIBRATE 3 CAL COUNT 4 MESSAGE The commands enclosed in square brackets are hidden unless the f...

Page 5: ...SK Burst FSK frequency shift keying modulation is enabled Burst modulation is enabled Sweep mode is enabled Hardware or remote interface command errors are detected The waveform is being output with an offset voltage Shift key has been pressed Press Shift again to turn off Enter Number mode is enabled Press Shift Cancel to disable Arbitrary waveform function is enabled Sine waveform function is en...

Page 6: ...1 Quick Start 1 ...

Page 7: ... Shift annun ciator will turn on Then press the key that has the desired label above it For example to select the AM amplitude modulation function press Shift AM the shifted version of the key If you accidentally press Shift just press it again to turn off the Shift annunciator Most keys also have a number printed in green next to the key To enable the number mode press Enter Number the Num annunc...

Page 8: ...ers up in the sine wave function at 1 kHz with an amplitude of 100 mV peak to peak into a 50Ω termination To review the power on display with all annunciators turned on hold down Shift as you turn on the function generator 3 Perform a complete self test The complete self test performs a more extensive series of tests than those performed at power on Hold down Shift as you press the Power switch to...

Page 9: ... plugged the function generator into is energized 2 Verify the power line voltage setting The line voltage is set to the proper value for your country when the function generator is shipped from the factory Change the voltage setting if it is not correct The settings are 100 120 220 or 240 Vac for 230 Vac operation use the 220 Vac setting See the next page if you need to change the line voltage se...

Page 10: ...tage selector until the correct voltage appears in the window 4 Replace the fuse holder assembly in the rear panel Verify that the correct line voltage is selected and the power line fuse is good Fuse 500 mAT for all line voltages HP Part Number 2110 0458 100 120 220 230 or 240 Vac 1 Chapter 1 Quick Start If the function generator does not turn on 17 ...

Page 11: ...handle To adjust the position grasp the handle by the sides and pull outward Then rotate the handle to the desired position Bench top viewing positions Carrying position Chapter 1 Quick Start To adjust the carrying handle 18 ...

Page 12: ... 1 Notice that the Num annunciator turns on and ENTER NUM flashes on the display indicating that the number mode is enabled 1 2 To cancel the number mode press Shift Cancel 3 Set the units to the desired value The units are selected using the arrow keys on the right side of the front panel As soon as you select the units the function generator outputs the waveform with the displayed frequency To t...

Page 13: ...ice that the Num annunciator turns on and ENTER NUM flashes on the display indicating that the number mode is enabled 50 To cancel the number mode press Shift Cancel 3 Set the units to the desired value The units are selected using the arrow keys on the right side of the front panel As soon as you select the units the function generator outputs the waveform with the displayed amplitude To turn off...

Page 14: ...ndicating that the number mode is enabled Notice that toggles the displayed value between and 1 5 To cancel the number mode press Shift Cancel 3 Set the units to the desired value At this point the function generator outputs the waveform with the displayed offset Notice that the Offset annunciator turns on indicating that the waveform is being output with an offset The annunciator will turn on whe...

Page 15: ... mode The displayed duty cycle is either the power on value or the previous value selected 50 DUTY This message appears on the display for approximately 10 seconds Repeat this step as needed 3 Enter the desired duty cycle 1 Notice that the Num annunciator turns on and ENTER NUM flashes on the display indicating that the number mode is enabled 45 To cancel the number mode press Shift Cancel 4 Outpu...

Page 16: ... SINC This message appears on the display for approximately 10 seconds Repeat this step as needed 2 Move across to the EXP_RISE choice 1 EXP_RISE 3 Select and output the displayed arbitrary waveform Notice that the Arb annunciator turns on indicating that the output is an arbitrary waveform The waveform is output using the present settings for frequency amplitude and offset unless you change them ...

Page 17: ...esired voltage 1 Notice that the Num annunciator turns on and ENTER NUM flashes on the display indicating that the number mode is enabled 155 To cancel the number mode press Shift Cancel 3 Set the units to the desired value At this point the function generator outputs the displayed dc voltage Notice that the Offset annunciator turns on all other annunciators are off indicating that a dc voltage is...

Page 18: ...strument configurations The instrument configuration is stored in non volatile memory and is remembered when power has been off STORE 1 This message appears on the display for approximately 10 seconds Repeat this step as needed 3 Store the instrument state in memory location 2 1 Use the up and down arrow keys to select the memory location STORE 2 To cancel the store operation press Shift Store aga...

Page 19: ...s Repeat this step as needed 6 Restore the instrument state The function generator should now be configured in the same state as when you stored the setup on the previous page When power is turned off the function generator automatically stores its state in memory location 0 You can recall the power down state but you cannot store the state to location 0 from the front panel Use the POWER ON LAST ...

Page 20: ...2 Front Panel Menu Operation 2 ...

Page 21: ... front panel menu This chapter does not give a detailed description of every front panel key or menu operation It does however give you a good overview of the front panel menu and many front panel operations See chapter 3 Features and Functions starting on page 53 for a complete discussion of the function generator s capabilities and operation If you purchased the Phase Lock Option for the HP 3312...

Page 22: ...cy in Hz for sweeping Sets the repetition rate in seconds for sweeping Selects linear or logarithmic sweeping 1 NEW ARB 2 POINTS 3 LINE EDIT 4 POINT EDIT 5 INVERT 6 SAVE AS 7 DELETE Initiates a new arb waveform or loads the selected arb waveform Sets the number of points in a new arb waveform 8 to 16 000 points Performs a linear interpolation between two points in the arb waveform Edits the indivi...

Page 23: ...erface language SCPI 1 SECURED 1 UNSECURED 2 CALIBRATE 3 CAL COUNT 4 MESSAGE The function generator is secured against calibration enter code to unsecure The function generator is unsecured for calibration enter code to secure Performs individual calibrations must be UNSECURED Reads the total number of times the function generator has been calibrated Reads the calibration string up to 11 character...

Page 24: ... to get from one level to the next Each of the three levels has several horizontal choices which you can view by moving left or right To turn on the menu press Shift Menu On Off To turn off the menu press Shift Menu On Off To execute a menu command press Enter To recall the last menu command that was executed press Shift Recall Menu To turn off the menu at any time without saving changes press Shi...

Page 25: ...ETER level is saved This is displayed after you press Menu Enter to execute the command MIN VALUE The value you specified on the PARAMETER level is too small for the selected command The minimum value allowed is displayed for you to edit MAX VALUE The value you specified on the PARAMETER level is too large for the selected command The maximum value allowed is displayed for you to edit EXITING You ...

Page 26: ...vel 1 There are six menu group choices available on the MENUS level Each choice has a letter prefix for easy identification A B etc D SYS MENU 3 Move down to the COMMANDS level within the SYS MENU The OUT TERM command is your first choice on this level 1 OUT TERM 4 Move across to the POWER ON command on this level 1 There are six command choices available in the SYS MENU Each choice on this level ...

Page 27: ...TE choice 1 There are two parameter choices for POWER ON LAST STATE 7 Save the change and turn off the menu The function generator beeps and displays a message to show that the change is now in effect You are then exited from the menu ENTERED Enter 1 You can also use the knob to scroll left or right through the choices on each level of the menu Chapter 2 Front Panel Menu Operation A front panel me...

Page 28: ... POWER ON 2 Move down to the PARAMETER choices The first parameter choice is LAST STATE the current setting from Example 1 LAST STATE 3 Move across to the DEFAULT choice 1 Set the parameter back to its original value DEFAULT 4 Save the change and turn off the menu The function generator beeps and displays a message to show that the change is now in effect You are then exited from the menu ENTERED ...

Page 29: ...el The MOD MENU is your first choice on this level A MOD MENU 2 Move down to the COMMANDS level within the MOD MENU The AM SHAPE command is your first choice on this level 1 AM SHAPE 3 Move across to the BURST CNT command on this level 1 There are ten command choices available in the MOD MENU 4 BURST CNT Menu On Off Shift 1 You can also use the knob to scroll left or right through the choices on e...

Page 30: ... level 5 Move the flashing cursor over to edit the last digit Notice that the rightmost digit is flashing the digit wraps around 00001 CYC 6 Increment the last digit until 4 is displayed 1 You decrement or increment each digit independently 00004 CYC 7 Save the change and turn off the menu The function generator beeps and displays a message to show that the change is now in effect You are then exi...

Page 31: ...is level 1 D SYS MENU 3 Move down a level to the OUT TERM command 1 OUT TERM 4 Move down a level and then across to the HIGH Z choice 1 With the output termination set to HIGH Z the function generator allows you to set the unloaded open circuit output voltage HIGH Z 5 Save the change and turn off the menu The function generator beeps and displays a message to show that the change is now in effect ...

Page 32: ... wave 1 Select the function frequency and amplitude of the carrier For the carrier waveform you can select a sine square triangle ramp or arbitrary waveform For this example select a 5 kHz sine wave with an amplitude of 5 Vpp 2 Select AM Notice that the AM annunciator turns on 3 Use the menu to select the shape of the modulating waveform After you enable the AM function the recall menu key will au...

Page 33: ... is now a sine waveform ENTERED 6 Set the modulating frequency to 200 Hz Notice that the AM annunciator flashes indicating that the displayed frequency is the modulating frequency for AM Also notice that the modulating frequency is displayed with fewer digits than the carrier frequency For more information on editing numbers in the menu refer to Menu Example 3 earlier in this chapter MOD 200 0 Hz ...

Page 34: ...depth also called percent modulation 080 DEPTH This message appears on the display for approximately 10 seconds Repeat this step as needed At this point the function generator outputs the AM waveform with the specified modulation parameters Level Shift 2 Chapter 2 Front Panel Menu Operation To output a modulated waveform 43 ...

Page 35: ...ier frequency to 3 kHz and the hop frequency to 500 Hz with an FSK rate of 100 Hz 1 Select the function frequency and amplitude of the carrier For the carrier waveform you can select a sine square triangle ramp or arbitrary waveform For this example select a 3 kHz sine wave with an amplitude of 5 Vpp 2 Enable FSK Notice that the FSK annunciator turns on 3 Use the menu to set the hop frequency Afte...

Page 36: ...hapter 500 0 Hz 5 Save the change and turn off the menu At this point the carrier and hop frequencies are set and output Now we will go back into the menu to set the FSK shift rate this is the rate at which the function generator shifts between the carrier frequency and hop frequency 6 Use the menu to set the FSK shift rate The recall menu key returns you to the FSK FREQ command which was the last...

Page 37: ...is chapter 100 0 Hz 9 Save the change and turn off the menu The function generator beeps and displays a message to show that the change is now in effect You are then exited from the menu ENTERED At this point the function generator outputs the FSK waveform You can also use an external signal to shift between the carrier frequency and hop frequency For more information see Frequency Shift Keying FS...

Page 38: ... burst source 0 degree starting phase and 100 Hz burst rate 1 Select the function frequency and amplitude for the burst For bursts you can select sine square triangle ramp or arbitrary waveforms For this example select a 1 kHz sine wave with an output amplitude of 5 Vpp 2 Enable the burst mode Notice that the Burst annunciator turns on 3 Use the menu to set the burst count After you enable the bur...

Page 39: ... the menu The function generator beeps and displays a message to show that the change is now in effect You are then exited from the menu ENTERED At this point the function generator outputs a continuous three cycle burst You can generate a single burst with the specified burst count by pressing the Single key from the front panel or applying a trigger pulse to the rear panel Ext Trig terminal For ...

Page 40: ...ngs internal sweep trigger linear spacing and 1 second sweep time 1 Select the function and amplitude for the sweep For sweeps you can select sine square triangle ramp or arbitrary waveforms For this example select a sine wave with a 5 Vpp amplitude 2 Enable the sweep mode Notice that the Swp annunciator turns on 3 Use the menu to select the start frequency After you enable the sweep mode the reca...

Page 41: ... you to the START F command which was the last command used before you exited the menu 1 START F 7 Move across to the STOP F command 2 STOP F 8 Move down a level and set the stop frequency to 5 kHz 5 000 KHz 9 Save the change and turn off the menu At this point the function generator outputs a continuous sweep from 50 Hz to 5 kHz You can generate one frequency sweep by pressing the Single key or a...

Page 42: ...enerator Pressing Single to enable the single trigger mode also enables the external trigger mode External triggering is like the single trigger mode except that you apply a trigger signal to the rear panel Ext Trig terminal The function generator is triggered on the rising edge of a TTL pulse The Single key is disabled when in remote the Rmt annunciator turns on when in remote and when a function...

Page 43: ...vel D SYS MENU 3 Move down a level and then across to the COMMA command 5 COMMA 4 Move down a level and then across to the OFF choice OFF 5 Save the change and turn off the menu The comma separator setting is stored in non volatile memory and does not change when power has been off or after a remote interface reset Enter Menu On Off Shift 15 000000 MHz With comma separator Without comma separator ...

Page 44: ...3 Features and Functions 3 ...

Page 45: ...lated Operations starting on page 109 Remote Interface Configuration starting on page 114 Calibration Overview starting on page 118 Power On and Reset State on page 123 Some knowledge of the front panel menu will be helpful before you read this chapter If you have not already read chapter 2 Front Panel Menu Operation starting on page 29 you may want to read it now Chapter 4 Remote Interface Refere...

Page 46: ...tive function For example if you output a 1 MHz sine wave and then change the function to triangle wave the function generator will adjust the output to 100 kHz the upper limit for triangle waves From the front panel FREQ LIMIT is displayed and the frequency is adjusted From the remote interface a 221 Settings conflict error is generated and the frequency is adjusted Possible Conflict with Output ...

Page 47: ...ough the waveform choices and make a selection press Arb List To select dc volts from the front panel press Offset and hold it down for more than 2 seconds Remote Interface Operation FUNCtion SHAPe SINusoid SQUare TRIangle RAMP NOISe USER DC You can also use the APPLy command to select the function frequency amplitude and offset with a single command AM Carrier AM Modulating Wave FM Carrier FM Mod...

Page 48: ... The five built in arbitrary waveforms can be output at a maximum of 5 MHz Function Sine Square Triangle Ramp Built In Arbs 1 Minimum Frequency 100 µHz 100 µHz 100 µHz 100 µHz 100 µHz Maximum Frequency 15 MHz 15 MHz 100 kHz 100 kHz 5 MHz 1 There are five built in arbitrary waveforms stored in non volatile memory sinc negative ramp exponential rise exponential fall and cardiac Number of Arb Points ...

Page 49: ... between 40 and 60 below 5 MHz the range is 20 to 80 The duty cycle is automatically adjusted if you select a frequency that is not valid with the present duty cycle For example if you set the duty cycle to 70 and then change the frequency to 8 MHz the function generator will automatically adjust the duty cycle to 60 the upper limit for this frequency From the front panel DUTY LIMIT is displayed a...

Page 50: ... if you output a 5 Vrms square wave into 50 ohms and then change the function to sine wave the function generator will adjust the output amplitude to 3 535 Vrms the upper limit for sine waves in Vrms From the front panel AMPL LIMIT is displayed and the amplitude is adjusted From the remote interface a 221 Settings conflict error is generated and the amplitude is adjusted Function Sine Square Trian...

Page 51: ...rmination Vpp is the output amplitude in volts peak to peak From the front panel MAX VALUE is displayed and the amplitude is adjusted From the remote interface a 221 Settings conflict error is generated and the amplitude is adjusted A momentary glitch occurs in the output waveform at certain voltages due to output attenuator switching This positive going glitch occurs when the output voltage cross...

Page 52: ...ffset Voltage on page 62 for more information To select dc volts from the front panel press Offset and hold it down for more than 2 seconds Front Panel Operation To set the output amplitude press Ampl Then use the knob arrow keys or Enter Number mode to set the amplitude Remote Interface Operation VOLTage amplitude MINimum MAXimum You can also use the APPLy command to select the function frequency...

Page 53: ...adjusted DC Offset and Output Termination The offset voltage is automatically adjusted and no error is generated if you change the output termination For example if you set the offset to 100 mVdc and then change the termination from 50 ohms to high impedance the displayed offset will double to 200 mVdc If you change from high impedance to 50 ohms the displayed offset will drop in half See Output T...

Page 54: ...age is not within two DAC Digital to Analog Converter counts of zero volts the Offset annunciator turns on Front Panel Operation To set the dc offset press Offset Then use the knob arrow keys or Enter Number mode to set the offset Remote Interface Operation VOLTage OFFSet offset MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single c...

Page 55: ... output units are remembered For example if you select Vrms from the remote interface the units are shown as Vrms on the front panel display Front Panel Operation Use the Enter Number units keys the arrow keys located on the right side of the front panel to select the output units You can also convert from one unit to another from the front panel For example to convert 2 Vpp to its equivalent valu...

Page 56: ...de or dc offset is automatically adjusted and no error is generated if you change the output termination For example if you set the amplitude to 10 Vpp and then change the termination from 50 ohms to high impedance the displayed amplitude will double to 20 Vpp If you change from high impedance to 50 ohms the displayed amplitude will drop in half If you specify a 50 ohm termination but are actually...

Page 57: ...matically sets the duty cycle to 50 for square waves Before attempting to set the duty cycle you must enable the square wave function From the front panel SQUARE ONLY is displayed if square wave is not currently active From the remote interface no error is generated but the specified duty cycle is remembered when you change to the square wave function The duty cycle setting is remembered when you ...

Page 58: ...nt panel DUTY LIMIT is displayed and the duty cycle is adjusted From the remote interface a 221 Settings conflict error is generated and the duty cycle is adjusted Front Panel Operation To set the duty cycle press Shift Duty the value appears on the display for approximately 10 seconds Then use the knob arrow keys or Enter Number mode to set the duty cycle Remote Interface Operation PULSe DCYCle p...

Page 59: ...nloaded point in the waveform For AM and FM the sync signal is referenced to the modulating signal not the carrier A momentary TTL high pulse 200 ns is output at each zero crossing point of the modulating signal For the triggered burst mode a TTL low signal is output while the specified number of cycles is output for the duration of the burst After the specified number of cycles has been output th...

Page 60: ...ge location For example an error is generated if you attempt to recall from memory location 2 but have never stored to that location From the front panel NOT STORED is displayed if nothing is stored in the specified memory location From the remote interface a 810 State has not been stored error is generated if nothing is stored in the specified memory location Any arbitrary waveforms downloaded to...

Page 61: ... cannot store to this memory location from the front panel However keep in mind that memory location 0 is automatically overwritten when the power is turned off Front Panel Operation To store the state press Shift Store Then use the knob arrow keys or Enter Number mode to select the memory location To restore the state press Recall Then use the knob arrow keys or Enter Number mode to select the me...

Page 62: ...ulation The AM annunciator turns on when AM is enabled Only one modulation mode can be enabled at a time When you enable AM the previous modulation mode is turned off Front Panel Operation Enable AM before setting up the other modulation parameters Press Shift AM to output an AM waveform using the present settings for the carrier frequency modulating frequency output amplitude and offset voltage R...

Page 63: ... command Carrier Frequency Carrier frequency 100 µHz to 15 MHz 100 kHz for triangle and ramp The default is 1 kHz For arbitrary waveforms the maximum carrier frequency depends on the number of points specified in the waveform The five built in arbitrary waveforms can be output at a maximum of 5 MHz Front Panel Operation Press the Freq key to select any valid frequency for the selected function the...

Page 64: ...default is Sine You can use the noise function as the modulating waveform However you cannot use the noise function or dc volts as the carrier waveform Front Panel Operation After enabling AM press Recall Menu to go directly to the AM SHAPE command in the menu 1 AM SHAPE MOD MENU Remote Interface Operation AM INTernal FUNCtion SINusoid SQUare TRIangle RAMP NOISe USER 3 Chapter 3 Features and Funct...

Page 65: ...tempt to set the frequency when AM is not enabled SELECT AM FM is displayed Remote Interface Operation AM INTernal FREQuency frequency MINimum MAXimum Modulation Depth The modulation depth is expressed as a percentage and represents the extent of the amplitude variation At 0 modulation the output amplitude is half of the selected value At 100 modulation the output amplitude equals the selected val...

Page 66: ...lated with two waveforms When the internal source is disabled external only the carrier waveform is modulated with the external waveform The Ext annunciator turns on to indicate that the function generator is expecting a modulating signal on the rear panel AM Modulation terminal You apply the external modulating waveform to the AM Modulation terminal The modulation depth is controlled by the signa...

Page 67: ...odulation The FM annunciator turns on when FM is enabled Only one modulation mode can be enabled at a time When you enable FM the previous modulation mode is turned off Front Panel Operation Enable FM before setting up the other modulation parameters Press Shift FM to output an FM waveform using the present settings for the carrier frequency modulating frequency output amplitude and offset voltage...

Page 68: ...tion Press any of the front panel function keys except Noise For arbitrary waveforms the Arb key selects the waveform that is currently downloaded Remote Interface Operation FUNCtion SHAPe SINusoid SQUare TRIangle RAMP USER You can also use the APPLy command to select the function frequency amplitude and offset with a single command 3 Chapter 3 Features and Functions Frequency Modulation FM 77 ...

Page 69: ...y and peak frequency deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz 15 1 MHz for sine and square 200 kHz for triangle and ramp and 5 1 MHz for arbitrary waveforms If you attempt to set the carrier frequency to a value that is not valid the function generator will automatically adjust the carrier frequency to equal the present deviation From the...

Page 70: ...function generator will accept only an internal modulating signal Modulating frequency internal source 10 mHz to 10 kHz The default is 10 Hz The sync signal for FM is referenced to the modulating signal not the carrier A momentary TTL high pulse 200 ns is output at each zero crossing point of the modulating signal The signal is output from the front panel SYNC terminal Front Panel Operation Press ...

Page 71: ...than or equal to the maximum frequency for the selected function plus 100 kHz 15 1 MHz for sine and square 200 kHz for triangle and ramp and 5 1 MHz for arbitrary waveforms If you attempt to set the deviation to a value that is not valid the function generator will automatically adjust the deviation to the maximum value allowed with the present carrier frequency From the front panel MAX VALUE is d...

Page 72: ... of cycles has been output the function generator waits for the next trigger You can configure the function generator to accept an internal trigger or you can send the trigger externally by pressing the front panel Single key or by applying a trigger signal to the rear panel Ext Trig terminal At power on the internally triggered burst mode is enabled External Gated Burst Mode In this mode the outp...

Page 73: ...nables the external trigger mode External triggering is like the front panel single trigger mode except that you apply a trigger signal to the rear panel Ext Trig terminal The function generator is triggered on the rising edge of a TTL pulse The Trig annunciator turns on when the function generator is waiting for a single or external trigger When the single or external trigger source is selected t...

Page 74: ...abled or disabled based on the logic level of the gate signal applied to the Ext Trig terminal When the gate signal is true TTL high the function generator outputs a continuous waveform When the gate signal is false TTL low the output is turned off zero volts or the dc offset level When the external gate source is selected the burst count burst rate burst phase and burst trigger source are ignored...

Page 75: ...requency The carrier frequency defines the repetition rate of the burst waveform in the triggered and external gated modes In the triggered mode the number of cycles specified by the burst count are output at the frequency of the carrier signal In the external gated mode the carrier frequency is output when the external gate signal is true TTL high Keep in mind that the carrier frequency is differ...

Page 76: ... valid the function generator will automatically adjust the frequency to the maximum value allowed with the present burst count From the front panel MAX VALUE is displayed and the carrier frequency is adjusted From the remote interface a 221 Settings conflict error is generated and the carrier frequency is adjusted Number of Arb Points 8 to 8 192 8k 8 193 to 12 287 12k 12 288 to 16 000 Minimum Fre...

Page 77: ... output for the duration of the burst After the specified number of cycles has been output the sync signal goes high until the next burst The sync signal is output from the front panel SYNC terminal For the external gated burst mode the sync signal is a TTL high when the output is positive relative to zero volts or the dc offset value The signal is a TTL low when the output is negative relative to...

Page 78: ...urce is selected the specified number of cycles is output continuously at a rate determined by the burst rate setting The burst rate frequency defines the interval between bursts When the single or external trigger source is selected the burst count and burst phase remain in effect but the burst rate is ignored The specified number of cycles is output each time Single is pressed or when a trigger ...

Page 79: ...unt and burst phase remain in effect but the burst rate is ignored When the external gate burst source is selected gated burst mode the burst count burst rate burst phase and burst trigger source are ignored these parameters are used for the triggered burst mode only It is possible to specify a burst rate which is too fast for the function generator to output with the specified carrier frequency a...

Page 80: ...c offset value in a positive going direction For arbitrary waveforms 0 degrees is the first data point downloaded to memory When the external gate source is selected gated burst mode the burst count burst rate burst phase and burst trigger source are ignored these parameters are used for the triggered burst mode only Front Panel Operation 6 BURST PHAS MOD MENU Remote Interface Operation BM PHASe d...

Page 81: ...re information on the fundamentals of FSK Modulation refer to chapter 7 Tutorial To Select FSK Modulation The FSK annunciator turns on when FSK is enabled Only one modulation mode can be enabled at a time When you enable FSK the previous modulation mode is turned off Front Panel Operation Enable FSK before you set up the other modulation parameters Press Shift FSK to output the waveform using the ...

Page 82: ...SK the sync signal is referenced to the FSK hop signal not the carrier A momentary TTL high pulse 200 ns is output on the transition to the hop frequency The signal is output from the front panel SYNC terminal Front Panel Operation Press the Freq key and select any valid frequency for the selected function the present amplitude and offset voltage are used Remote Interface Operation FREQuency frequ...

Page 83: ...l The hop frequency is output when a high TTL level is applied For FSK the sync signal is referenced to the FSK hop signal not the carrier A momentary TTL high pulse 200 ns is output on the transition to the hop frequency The signal is output from the front panel SYNC terminal Front Panel Operation After enabling FSK press Recall Menu to go directly to the FSK FREQ command in the menu 8 FSK FREQ M...

Page 84: ...lected the rate at which the output frequency shifts between the carrier frequency and hop frequency is determined by the FSK rate specified When the external source is selected the output frequency is determined by the signal level on the rear panel FSK terminal When a low TTL level is present the carrier frequency is output When a high TTL level is present the hop frequency is output The maximum...

Page 85: ...For more information on the fundamentals of frequency sweeps refer to chapter 7 Tutorial To Select Sweep Modulation The Swp annunciator turns on when the sweep mode is enabled Only one modulation mode can be enabled at a time When you enable the sweep mode the previous modulation mode is turned off Front Panel Operation Enable the sweep mode before you set up the other sweep parameters Press Shift...

Page 86: ... five built in arbitrary waveforms can be output at a maximum of 5 MHz To sweep up in frequency set the start frequency stop frequency To sweep down in frequency set the start frequency stop frequency The sync signal is a TTL low at the start of the sweep when the start frequency is output and is a TTL high at the end of the sweep when the stop frequency is output The signal is output from the fro...

Page 87: ...rt frequency to the stop frequency Front Panel Operation 3 SWP TIME SWP MENU Remote Interface Operation SWEep TIME seconds MINimum MAXimum Sweep Mode You can sweep with either linear or logarithmic spacing The output frequency of a linear sweep changes linearly during the duration of the sweep For logarithmic spacing the output frequency changes exponentially during the duration of the sweep Sweep...

Page 88: ... to enable the single trigger mode also enables the external trigger mode External triggering is like the front panel single trigger mode except that you apply a trigger signal to the rear panel Ext Trig terminal The function generator is triggered on the rising edge of a TTL pulse The Trig annunciator turns on when the function generator is waiting for a single or external trigger Front Panel Ope...

Page 89: ... sweep each time you press Single from the front panel Continue pressing this key to re trigger the function generator Pressing Single to enable the single trigger mode also enables the external trigger mode External triggering is like the front panel single trigger mode except that you apply a trigger signal to the rear panel Ext Trig terminal The function generator is triggered on the rising edg...

Page 90: ...he source is set to internal trigger front panel or immediate remote interface when power has been off or after a remote interface reset To select the trigger source from the remote interface use the following command The APPLy command automatically sets the trigger source to IMMediate TRIGger SOURce IMMediate EXTernal BUS Internal Triggering In this trigger mode the function generator continuousl...

Page 91: ...pplied to the Ext Trig terminal The function generator outputs one burst or initiates one sweep each time Ext Trig receives the rising edge of a TTL pulse See also Ext Trig FSK Burst Input Terminal on page 102 Front Panel Operation The external trigger mode is like the single trigger mode except that you apply the trigger to the Ext Trig terminal Pressing Single to enable the single trigger mode a...

Page 92: ...e send the following command TRIGGER SOURCE BUS To trigger the function generator from the remote interface HP IB or RS 232 send the TRG trigger command You can also trigger the function generator from the HP IB interface by sending the IEEE 488 Group Execute Trigger GET message The following statement shows how to send a GET using HP BASIC TRIGGER 710 Group Execute Trigger The following statement...

Page 93: ...h TTL level is present the FSK hop frequency is output The Ext annunciator turns on when selected Triggered Burst Mode Press Single or execute TRIG SOUR EXT from the remote interface to enable the triggered burst mode burst must be enabled When the rising edge of a TTL pulse is received the function generator outputs a burst waveform with the specified number of cycles The Trig annunciator turns o...

Page 94: ...ore an arbitrary waveform from the front panel To download an arbitrary waveform from the remote interface see Arbitrary Waveform Commands starting on page 174 For this example you will create and store a pulse waveform containing 400 points 1 Turn on the menu A MOD MENU 2 Move across to the EDIT MENU choice on this level C EDIT MENU 3 Move down a level to the NEW ARB command There are seven comma...

Page 95: ...ile memory CLEAR MEM 5 Turn on the waveform edit mode The function generator beeps and displays a message to show that the waveform edit mode is now enabled You are then exited from the menu LOADING 6 Use Recall Menu to return to the NEW ARB command 1 NEW ARB 7 Move across to the POINTS command on this level 2 POINTS 8 Move down a level and set the number of points to 400 Ù00400 PNTS Enter Recall ...

Page 96: ...m points use the LINE EDIT command in the EDIT MENU The function generator temporarily rescales the waveform amplitude between 1 and 1 at 1 kHz 11 Move across to the LINE EDIT command on this level 3 LINE EDIT 12 Move down a level and set point 100 to a value of 1 Use the left right arrow keys to move between the point field left and the floating point value right The comma at the right side of th...

Page 97: ...Enter key the start point and stop point are restored 00299 1 0000 15 Save the start and stop points and output the waveform COMPUTING 16 Save the waveform and turn off the menu The function generator beeps and displays a message to show that the waveform is now stored in volatile memory You are then exited from the menu EXITING 17 Use Recall Menu to return to the LINE EDIT command 3 LINE EDIT 18 ...

Page 98: ...llowing names ARB1 ARB2 ARB3 or ARB4 ARB1 NEW 20 Save the waveform and turn off the menu The function generator beeps and displays a message to show that the waveform is being saved You are then exited from the menu SAVING The waveform is now stored in non volatile memory and is output from the function generator The name that you used to store the waveform should appear in the waveform list press...

Page 99: ...However you cannot edit any of the five built in arbitrary waveforms Use the GET option under the NEW ARB command in the EDIT MENU to load an existing user defined waveform Then use the LINE EDIT POINT EDIT and INVERT commands to edit the waveform The INVERT command in the EDIT MENU takes the inverse of each point in the specified waveform by changing the sign You can use the DELETE command in the...

Page 100: ...powers up in its default configuration see page 123 When the recall mode is enabled the function generator powers up in the power down configuration The power down recall setting is stored in non volatile memory and does not change when power has been off or after a remote interface reset The power down recall mode remembers the function including arbitrary waveforms frequency amplitude dc offset ...

Page 101: ... errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the function generator responds with 0 No error The error queue is cleared when power has been off or after a CLS clear status command has been executed The RST reset command does not clear the error queue Front Panel Operation 3 ERROR SYS MENU If the ERROR annunciator is on press Shi...

Page 102: ... ERROR annunciator turns on See the Service Guide for instructions on returning the function generator to Hewlett Packard for service Front Panel Operation 4 TEST SYS MENU Another way to perform the complete self test from the front panel is as follows Hold down Shift as you press the Power switch to turn on the function generator hold down the key for more than 5 seconds The self test will begin ...

Page 103: ...aracters of the message on the front panel any additional characters are truncated Commas periods and semicolons share a display space with the preceding character and are not considered individual characters When a message is displayed information relating to the output waveform such as frequency and amplitude is not sent to the display Sending a message to the display from the remote interface o...

Page 104: ...has three microprocessors for control of various internal systems You can query the function generator to determine which revision of firmware is installed for each microprocessor The function generator returns three numbers The first number is the firmware revision number for the main generator processor the second is for the input output processor and the third is for the front panel processor F...

Page 105: ...ont panel when you turn on the function generator The address is set to 10 when the function generator is shipped from the factory The HP IB address can be set from the front panel only The address is stored in non volatile memory and does not change when power has been off or after a remote interface reset Your HP IB bus controller has its own address Be sure to avoid using the bus controller s a...

Page 106: ... front panel when you turn on the function generator Your HP IB bus controller has its own address Be sure to avoid using the bus controller s address for any instrument on the interface bus Hewlett Packard controllers generally use address 21 If you enable the RS 232 interface you must select the baud rate and parity to be used RS 232 is displayed momentarily on the front panel when you turn on t...

Page 107: ...on RS 232 You can select the parity for RS 232 operation The function generator is configured for no parity and 8 data bits when shipped from the factory The parity can be set from the front panel only Select one of the following None 8 data bits Even 7 data bits or Odd 7 data bits When you set the parity you are indirectly setting the number of data bits The parity selection is stored in non vola...

Page 108: ...peration 5 LANGUAGE I O MENU SCPI Language Version Query You can determine the SCPI version with which the function generator is in compliance by sending a query from the remote interface The SCPI version can be queried from the remote interface only Remote Interface Operation SYSTem VERSion Returns a string in the form YYYY V where the Y s represent the year of the version and the V represents a ...

Page 109: ...terface reset To secure the function generator from the remote interface the security code may contain up to 12 alphanumeric characters as shown below The first character must be a letter but the remaining characters can be letters or numbers You do not have to use all 12 characters but the first character must always be a letter A _ _ _ _ _ _ _ _ _ _ _ 12 characters To secure the function generat...

Page 110: ...nd is hidden when the function generator is secured To unsecure the function generator go to the PARAMETER level of the SECURED command enter the security code and then press Enter When you go to the COMMANDS level in the CAL MENU again you will notice that the function generator is unsecured Notice also that the CALIBRATE command is no longer hidden and you can perform a calibration Remote Interf...

Page 111: ...e above command when you go into the CAL MENU To secure the function generator go to the PARAMETER level of the UNSECURED command enter the security code and then press Enter When you go to the COMMANDS level in the CAL MENU again you will notice that the function generator is secured Notice also that the CALIBRATE command is now hidden and you cannot perform a calibration Remote Interface Operati...

Page 112: ...Then enter the new code For example CAL SEC STAT OFF HP033120 Unsecure with old code CAL SEC CODE ZZ002133 Enter new code Calibration Count You can determine the number of times that your function generator has been calibrated Your function generator was calibrated before it left the factory When you receive your function generator read the count to determine its initial value The calibration coun...

Page 113: ...ither the front panel menu or the remote interface The calibration message may contain up to 40 characters However the function generator can display only 11 characters of the message on the front panel additional characters are truncated The calibration message is stored in non volatile memory and does not change when power has been off or after a remote interface reset Front Panel Operation 4 ME...

Page 114: ...ate Sine wave 1 kHz 100 mV peak to peak 0 00 Vdc Volts peak to peak 50 ohms Power On Reset State 1 kHz Sine wave 100 Hz Sine wave 100 1 kHz Sine wave 10 Hz Sine wave 100 Hz 1 kHz Sine wave 1 cycle 100 Hz 0 degrees 1 kHz Sine wave 100 Hz Sine wave 10 Hz Off 100 Hz 1 kHz 1 second Linear Power On Reset State Disabled On On Power On Reset State Internal Power On Reset State 10 HP IB IEEE 488 9600 baud...

Page 115: ...8 Specifications 8 ...

Page 116: ...Bc 6 dB octave 55 dBc in a 30 kHz band SIGNAL CHARACTERISTICS Square wave Rise Fall Time Overshoot Asymmetry Duty Cycle Triangle Ramp Arb Rise Fall Time Linearity Settling Time Jitter 20 ns 4 1 5 ns 20 to 80 to 5 MHz 40 to 60 to 15 MHz 100 ns typical 0 1 of peak output 250 ns to 0 5 of final value 25 ns OUTPUT CHARACTERISTICS 1 Amplitude into 50Ω 2 Accuracy at 1 kHz Flatness 100 kHz 100 kHz to 1 M...

Page 117: ...0 ms 100 ms 350 ms FREQUENCY SWEEP Type Direction Start F Stop F Time Source Linear or Logarithmic Up or Down 10 mHz to 15 MHz 1 ms to 500 sec 0 1 Single External or Internal REAR PANEL INPUTS External AM Modulation External Trigger FSK Burst Gate 1 Latency Jitter 5 Vpk 100 Modulation 5 kΩ Input Resistance TTL low true 1 3 µs 25 ns Arb Download Times over HP IB Arb Length Binary ASCII Integer ASCI...

Page 118: ... x 88 5 mm x 348 3 mm 4 kg 8 8 lbs Safety Designed to EMC Vibration and Shock Acoustic Noise Warm Up Time Warranty Remote Interface Programming Language Accessories Included EN61010 CSA1010 UL 1244 EN55011 EN50082 1 MIL 461C 2 data on file MIL T 28800E Type III Class 5 data on file 30 dBa 1 hour 3 years standard IEEE 488 and RS 232 standard SCPI 1993 IEEE 488 2 User s Guide Service Guide Quick Ref...

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HP 33120A, User Manual

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