Page 1 of 1

Lock in Amplifier

Posted: Thu Apr 19, 2018 6:50 am
by Ste_Trat
Hi all,

Just came a across a problem which needs a lock in amp, and my red pitaya is just sitting around waiting for a job. After little research i found, that some guys tried to implement a lock-in on the rp, but i havenĀ“t found any detailed description on how to do that.

3 things are coming up to my mind:
- an analog lock in
- a variant with gnuradio
- a fully digital one implemented on the red pitaya

Has anyone of you, in his or her life, came a across an affordable idea or solution within a frequency range of a few tens of kHz ?

any hints are appreciated

Re: Lock in Amplifier

Posted: Thu Aug 02, 2018 9:40 am
by mkphuthi
Feel free to see my post 'Improvements to my Lock in Amplifier implementation with PyRPL "

Re: Lock in Amplifier

Posted: Tue Nov 06, 2018 5:03 pm
by keramatnejad
Hello,

I just came across your impressive work. I am also working on using the redpitaya as the locked-in amplifier. I know I can demodulate a signal with extracting "iq2" and "iq2-2" values as X and Y and I have successfully tested this. However, I have to demodulate two signals. In other words, I need another set of "iq2, and iq2-2" for the demodulation of the second signal.

Option 1: I believe one way is to use another redpitaya for the demodulation of the second signal. However, I am having difficulty syncing the two Redpitayas. Right now, the iq2 and iq2-2 of the second redpitaya constantly changing due to this issue. Therefore, I was wondering if there is a way sync the demodulation reference signals for both of the redpitayas. Both signals need to be demodulated with a singles reference signal.

Option 2: Is there a way, maybe a code, that could be used to set the iq0 and iq1 as another iq2 and iq2-2 and therefore only use one redpitaya for the demodulation of the two signals?

I appreciate it if you share any knowledge or experience on this issue.

Best Regards,