Hi,
I am using a lock in amplifier approach.
I use a arbitrary functiong generator to generate the ramp(125 Hz and sinusoid waveforms(25 kHz).
then I input it to the NI 5122 scope. Trigger it using the function generator.
I record the signals using a sampling rate of 10 MS/s.
Then I demodulate this signal in PC multiplying with a sine wave(10 Ms/s) and successively low pass filtering.
Is this a valid approach? Will there be a reduction in the SNR?
Or do I need to use a sine reference signal from the function generator input it into a different channel of the NIscope and multiply it with the signal and low pass filter it?
Or alternatively is it possible to generate a sine wave in software from the phase locked loop?
Thanks,
