I want to measure THD of a amplifier.
Is this possible whit a pc-scoop (PCS500) and signal-generator :?:
If it is not “too good” amplifier you may approximate the distortion with the PCS500 and the generator.
To get largest dynamic range, please select:
Options / FFT Options: Vector Average
Options / FFT Window: Hanning
Set trigger ON and use as large as possible waveform amplitude on the oscilloscope display.
You may first check the distortion of the oscilloscope and the generator by connecting the signal directly to the PCS500 and checking the harmonic signal level. The harmonics should be about at the level of -70dB or below compared to the fundamental signal.
If you use the function generator PCG10 of PCGU1000 then do not select exactly 1kHz but slightly different frequency (997Hz or 1003Hz) to do the measurement. This way you avoid the sampling frequency synchronization of the oscilloscope and you get better (more real) results.