demodulation of a filtered signal

[AlexMalm]

Hi

I have an interferometer and am measuring the output of the device on a photodiode detector and then doing analysis in Labview.

Put plainly, Im looking at the power spectrum of the signal, and am modulating using an EOM in the reference arm of the interferometer in order to read signals that would otherwise be lost to 1/f noise.

Until now we have just been measuring the modulated signal, and subtracting off the modulation frequency from any peaks we measure in the power spectrum, but it would be more convienient to be able to demodulate the signal and measure the origional peak but without noise.

The plan was to high pass filter the signal to remove the noise and then demodulate to recover the signal, however I am unable to wire the output of my filter to the input of the demodulation vi.

I have tried converting the output of the filter in various different types in order to get it to be accepted by the demodulation vi, but every time I have, there has been another error arise.

Any advice would be greatly appreciated.

[AlexMalm]

Any suggestions on how to do this, or even another method would be much appreciated

[LanxiZ]

Dear AlexMaim,

The reason why you couldn't wire the output of the filter vi to the demodulatiion vi is because the input to the demodulation vi is in waveform type which is a cluster containing 3 elements.

You need to use unbundle by name function to feed the output from the filter vi to the demodulation vi, please have a look at the vi attached in this email to see what I mean.

Thank you and have a good day.

Regards,

Lanxi

[AlexMalm]

Thanks

That seems to have worked

I had tried something similar but must have defined the cluter in the wrong way.