Recording audio frequency signals

Signals to measure



Best HW depends on notebook and the signal to measure.

This was sufficient for upto 16V signal (but soundcard mixer settings can tune this).

Note that there is a high-pass filter involved (the soundcard cuts freq below 20Hz), so the squarewaves are changed in a predictable way: possible to evaluate waveforms, but takes some getting used to. For us it immediately made temporary loss of injector signal (due to fully pressed TPS or processor reset) visible.

Possible to test and tune on the table with mdh commands. Eg. recording output from i259 chip at the IGBT gates and mdh02..72 for signal=low and mdh82..f2 for signal=high - make sure not to fry anything that's accidentally left on output, eg. a coil.


See also