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3.7 Analyzing a Differential Communication Signal
You are having intermittent problems with a serial data communication link, and
you suspect poor signal quality. Set up the oscilloscope to show you a snapshot of the
serial data stream so you can verify the signal levels and transition times.
Because this is a differential signal, you use the math function of the
oscilloscope to view a better representation of the waveform.
To activate the differential signals connected to channel 1 and channel 2, follow
these steps:
1) .Press the CH 1 button and set the Probe option attenuation to 10X.
2). Press the CH 2 button and set the Probe option attenuation to 10X.
3). Set the switches to 10X on the probes.
4). Press the AUTO button.
5). Press the “MATH” button to see the Math Menu.
6). Press the “Operation” option button and select “
－
”.
7). Press the “CH1
－
CH2” option button to display a new waveform that is the
difference between the displayed waveforms.
8). You can adjust the vertical scale and position of the Math waveform. To do so,
follow these steps:
a. Remove the channel 1 and channel 2 waveforms from the display.
b. Turn the CH 1 and CH 2 VOLTS/DIV and VERTICAL POSITION knobs to adjust
the vertical scale and position.
NOTE
. First be sure to compensate both probes. Differences in probe
compensation appear as errors in the differential signal.
Summary of Contents for SDS1000 Series
Page 146: ...138 Coupling DC...
