143
Figure 4.4 – Out of Phase Signals in XY Mode (45 degrees)
Sin θ=A/B or C/D where θ=phase shift (in degrees) between the
two signals from the formula above, you could get:
θ=±arcsine (A/B) or ±arcsine (C/D)
If the main axis of the ellipse is at quadrant II and IV, θ must be in
the range of (0-π/2) or (3π/2-2π). If the main axis is at quadrant I
and III, θ must be in the range of (π/2-π) or (π-3π/2).
4.7 Analyzing a Differential
Communication Signal
You are having intermittent problems with a serial data communication
link and suspect poor signal quality. Set up the oscilloscope to show a
snapshot of the serial data stream so you can verify the signal levels and
transition times.
Because this is a differential signal, you can use the math function of the
oscilloscope to view a better representation of the waveform.
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