5520A
Operators Manual
8-78
8-105. Frequency Response Calibration Procedure for an Oscilloscope
This sample procedure, which verifies the frequency response on your oscilloscope, is
usually performed after the pulse response is verified.
This procedure checks the bandwidth by finding the frequency at the -3 dB point for
your oscilloscope. The reference sine wave in this procedure has an amplitude of 6
divisions, so that the -3 dB point can be found when the amplitude drops to 4.2 divisions.
Before you start this example procedure, verify that you are running the oscilloscope
option in Levsine mode. If you are, the Control Display shows the following menu.
gl032i.eps
Perform the following sample procedure to calibrate the frequency response.
1. Reconnect the signal by pressing the O key on the 5520A. Select 50Ω 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
1 2 0 g V; then press E.
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 e to bring a cursor into the
Output Display, move the cursor with the L key, and turn the rotary knob to
adjust the value. (See “Fine-Tuning Values” earlier in this chapter.)
gl009i.bmp
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