Created on 2008-08-28 10:48:00
Measuring very low frequency signals
The APx525 can directly generate sine waves as low as .1 Hz, all the APx instruments can go even lower, all the way to DC, using the file playback function. Measuring very low frequency signals is not as simple. Generally the APx instruments will measure signals down to 5 Hz transparently. To measure below 5 Hz the following steps should be taken:
- In signal path setup set the Max Bandwidth control to 20 kHz
- In signal path setup, Advanced… set the instrument to DC coupled
- Fix the input range in the measurement view(s) you are using
Finally, you will need to have some patience. Making accurate measurements at very low frequencies requires some time. It may take as much as 10 minutes to make an accurate CMRR measurement at .1 Hz, but it can be done.