Scope Calibration Option
Calibrating the Pulse and Frequency Response on an Oscilloscope
15
gl032i.eps
Perform the following sample procedure to calibrate the frequency response.
1.
Reconnect the signal by pressing the
key on the 5080A. Select 50
Ω
impedance
or use a 50
Ω
external termination directly at the oscilloscope input.
2.
Adjust the sine wave settings in the Output Display according to the calibration
recommendations in your oscilloscope manual. For example, for the Fluke PM3392A
oscilloscope, start at 120 mV @ 50 kHz. To enter 120 mV, press
; then press
.
3.
Adjust the oscilloscope as necessary. The sine wave should appear at exactly six
divisions, p-p, as shown below.
If necessary, make small adjustments to the voltage amplitude until the wave reaches
exactly six divisions. To fine-tune the voltage, press
to bring a cursor into the
Output Display, move the cursor with the
key, and turn the rotary knob to adjust
the value. (See “Fine-Tuning Values” earlier in this chapter.)
gl009i.bmp
4.
Increase the frequency to 60 MHz (for 100 MHz instruments), or 150 MHz (for
200 MHz instruments). To enter 60 MHz, press
; then press
.
5.
Continue to increase the frequency slowly until the waveform decreases to
4.2 divisions, as shown below.
To increase the frequency slowly, fine-tune it using the rotary knob, To do this, press
to place a cursor in the Output Display. Press
again to place it in the
frequency field, and use the
and
keys to move it to the digit you want to
change. Then change the value by turning the rotary knob.
Continue making small increments in the frequency until the signal drops to
4.2 divisions. At 4.2 divisions, the signal is at the frequency that corresponds to the
-3 dB point.
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