Questions tagged [lock-in-amplifier]
7 questions
5
votes
1 answer
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 multiply the signal only with either cosine or…
james
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3
votes
1 answer
How to improve the performance of my low pass filter design
Goal:
I am designing a low-noise, 8-pole, low pass filter to use in the output stage of a lock in amplifier. The filter needs to attenuate wide-band noise and a doubled carrier frequency in the range of 40 kHz to ~800 kHz. The higher the attenuation…
Joshua S.
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3
votes
2 answers
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 thinking of building a module based around the…
Dimitris
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1
vote
1 answer
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. The MCT detector, in turn, is connected to its…
Strelok
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1
vote
1 answer
What is the technical description of 'sensitivity' in Lock-In amplifiers?
While I understand that the sensitivity in Lock In amplifiers should be as close as possible to the range within which the signal to be measured lies, I could not find a more technical description of how exactly is this implemented. (Take, for…
student1
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0
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Connecting an SRS 830 Lock-in amplifier to a NI DAQ 6120
I am currently using a NI 6210 connected to the R and Phi outputs of a SRS 830 lock-in amplifier.
However, a stupid doubt settled in my head: am I setting the system properly? Why is it stupid? It has to do with the referential used to define…
Strelok
- 111
- 2
0
votes
2 answers
Reference signal choice for lock-in amplifier
How do you choose the reference frequency when using a lock-in amplifier?
I want to measure the amount of lateral deflection of a laser reflected by a surface that will be oscillating very slightly. I'm going to modulate the laser at a set…
iwantmyphd
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