Terrible waveform.
Make sure you use a 10x scope probe with the short ground spring on it, not the alligator clip ground lead. The inductance of the clip wire turns any signal with even moderately fast edges into a mess. Then, probe the SPDIF RCA output. If the scope tip is too short to reach inside the RCA, you can stick a male RCA connector in to get a better probing point. The important thing is the scope ground spring should be on the RCA ground, not somewhere else, and especially not with the alligator clip on the chassis.
Do not use a 1x scope probe.
If you use a RCA to BNC coax to plug the scope directly, and even if you use a 75R coax to match the output impedance, the scope doesn't have a 75R termination. It's simpler to just use a good x10 probe.
Make sure you use a 10x scope probe with the short ground spring on it, not the alligator clip ground lead. The inductance of the clip wire turns any signal with even moderately fast edges into a mess. Then, probe the SPDIF RCA output. If the scope tip is too short to reach inside the RCA, you can stick a male RCA connector in to get a better probing point. The important thing is the scope ground spring should be on the RCA ground, not somewhere else, and especially not with the alligator clip on the chassis.
Do not use a 1x scope probe.
If you use a RCA to BNC coax to plug the scope directly, and even if you use a 75R coax to match the output impedance, the scope doesn't have a 75R termination. It's simpler to just use a good x10 probe.
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The waveform is perfect with the oscilloscope calibrator. The most likely there is a resonance between capacitance of a probe and inductance. The probe has 60Mhz bandwidth at 10x and the oscilloscope has a 70Mhz bandwidth. Tomorror I'll put a series 200 ohm resistor to damp this oscillation. Or maybe the oscilloscope bandwidth is too small for that step signal.
Yes, my scope has 2 probes. It is a GWInstek GDS-2072E
Yes, my scope has 2 probes. It is a GWInstek GDS-2072E
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