Hi,
Can anyone help me figure out what I am doing wrong when trying to measure audio signals using two channels of my oscilloscope. I really want to avoid buying a differential probe, and I am trying to use the math operations on my Rigol 1054Z to simply measure the difference in voltage between the two probes. If I connect the ground lead of a probe to the shield of an audio cable and put the probe on the signal wire, I can see the audio signal without problems. But I've tried using the math operations with A set to Channel 1 and B set to Channel 2, then A - B with the operation enabled, and I've tried inverting one channel or keeping both channels non-inverted but no matter what I just get a bunch of noise. And the noise is showing up as like 50v or more in some cases. Is it possible my scope is damaged or something?
Can anyone help me figure out what I am doing wrong when trying to measure audio signals using two channels of my oscilloscope. I really want to avoid buying a differential probe, and I am trying to use the math operations on my Rigol 1054Z to simply measure the difference in voltage between the two probes. If I connect the ground lead of a probe to the shield of an audio cable and put the probe on the signal wire, I can see the audio signal without problems. But I've tried using the math operations with A set to Channel 1 and B set to Channel 2, then A - B with the operation enabled, and I've tried inverting one channel or keeping both channels non-inverted but no matter what I just get a bunch of noise. And the noise is showing up as like 50v or more in some cases. Is it possible my scope is damaged or something?