Questions tagged [lock-in-amplifier]
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12 questions
0 votes
1 answer
93 views
How can I reduce noise and improve femtoampere sensitivity with the SR865A lock-in amplifier?
I'm measuring (or at least trying to) low-level currents using the SR865A lock-in amplifier. My sample produces a DC current modulated by a mechanical chopper at around 1 kHz, so the signal appears as ...
- 11
-1 votes
2 answers
110 views
Setup and Signal scale in a double demodulation scheme using two lock in amplifiers (SRS 830)
I am not an electrical engineer and my experience is somewhat limited. I would like to make what I assume is going to be a bunch of goofy questions: Consider a signal that is modulated at two ...
- 109
1 vote
2 answers
295 views
How to generate a sine wave that is in phase with a generated square wave at 1MHz for lock-in amplifier?
I am building a lock in amplifier (LIA) for fluorescence lifetime measurement using off the shelf components, after going through literature, I have decided to use square wave for excitation of the ...
1 vote
1 answer
197 views
On the understanding of signals from an IR detector coupled to a lock in amplifier
I have a CW laser which is modulated by an optical chopper rotating at 1kHz. The modulated CW beam struck a sample holder and the absorption signal is recorder via an Infrared Associates MCT detector. ...
- 109
3 votes
2 answers
2k views
Lock-in amplifier (AD630)
I've got a signal that consists of 2 square waves at 2 different frequencies in the kHz range, about 10 Hz apart. I need to determine the relative amplitudes of 2 different known frequencies and I was ...
- 31
5 votes
1 answer
1k views
Lock-in amplifier: Why multiplication with Cos and Sin?
I have two questions: Why does a lock-in amplifier multiply the incoming signal s(t) with both a cosine and a sine reference and not just a single one? What problem may eventually arise, if you ...
- 153