Function Generator Setup

ECE 385

HP 33120A Function Generator Setup

The HP 33120A function/arbitrary waveform generator uses direct digital-synthesis techniques to create a stable, accurate output signal for clean, low-distortion sine waves. It also gives you fast rise and fall-time square waves, and linear ramp waveforms down to 10 MHz.

In ECE 249 we will primarily use square waves to generate the clock signals, and other inputs, for our digital circuits. Hence, it is very important that the function generator is set properly before each use to ensure proper circuit function. Do not assume your generator is properly setup. Failure to setup your generator will result in circuit malfunction and may damage your chips or the generator.

Setup Procedure:

Turn function generator on.
Select high impedance output.

Press the blue 'Shift' button then the 'Enter' button.
You are now on 'A: MOD MENU'
Hit the '>' button three (3) times.
You are now on the 'D: SYS MENU'
Hit the '(' button twice.
If the display says 'HIGH Z', skip to step 2e.
If the display says '50 OHM' go on to step 2d.
Press the '>' button once.
The display should say 'HIGH Z', if it does not repeat this step again.
Press the 'ENTER' button.
The display will flash 'ENTERED'

Set a 0 to 5 Volt square wave signal.

Select a square wave by pressing the ' .' button
Press the 'Ampl' button.
Turn knob to set '5.000 VPP'
Press the 'Offset' button.
Turn knob to set '+2.500 VDC'

Set signal frequency

Press the 'Freq' button.
Turn knob until desired frequency is set.

Check the signal from the output port with the oscilloscope.

HP 33120A Single Step Mode

Single step mode is often useful in debugging clocked circuits, as it allows you to send single clock pulses instead of a continuous clock.

Setup Procedure:

Follow the steps shown in Function Generator Setup to set up your desired signal
Set up burst mode

Press the blue 'Shift' button then the 'Sawtooth Wave' button (Button #4).
The word 'Burst' should appear in the middle bottom of the display
Press the blue 'Shift' button, then press the '<' button once
You are now on the '4: BURST CNT'
Hit the 'V' button once.
The display will say '00001 CYC'
Turn the dial to set a value for 'CYC.' This value is the number of pulses that will be sent each time you press the 'Single' button. E.g. if you set the count to '00003,' when you press 'Single' you will get a square wave that looks like: __________|¯¯|__|¯¯|__|¯¯|___________
Press the 'ENTER' button.
The display will flash 'ENTERED'

Press the 'Single' button (Button #9) to begin single step mode.
From now on, every time you press 'Single,' the number of clock pulses specified by the CYC value will be sent.
To exit single step mode, press the blue 'Shift' button then the 'Sawtooth Wave' button (Button #4)

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