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Hi, is it possible to design a Lock in amplifer in PSoC5. I want to work in operation range from 100-500kHz. One limit which I already have discovered is that I only have access to one filter block (for lowpass filtering). The main concept is shown below.
Best regards
Solved! Go to Solution.
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JaRa,
Please note that PSoC analog Modulator only inverts signal amplitude (+A/-A), it is not an analog multiplier.
Also Analog Devices recently ran advertisements here for their Zero-IF radios. These are essentially high-frequency lock-in amplifiers.
I recommend reading this paper re lock-in detection first (copy attached)
Synchronous Detectors Facilitate Precision Low-Level Measurements | Analog Devices
https://www.edn.com/design-a-dsp-lock-in-amplifier-part-2-design-methodology/
The impedance analyzer project by Chris Keeser was posted on the forum long time ago. It basically used 1kHz sine for excitation, and DelSig_ADC built-in modulator to demodulate the feedback signal. Since only one DelSig_ADC is available on PSoC5, the in-phase and quadrature measurements were taken separately.
You can find basic lock-in detector project using DelSig_ADC below. I am not sure how much up in frequency it can go. I tested it up to 10kHz, but the modulator "might" work at 100-500k.
Re: PSoC Today! - Synchronous Detection Detail
/odissey1
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JaRa,
PSoC5 was designed with audio frequency operation in mind, so F <100kHz is where it operates best. It doesn't preclude from using it at higher frequencies, with some performance penalties.
If you consider a general purpose lock-in, you might noticed, that commercial systems are divided into two distinct groups: 0-100kHz, and 1-100MHz based on operation principle. That gives an idea that implementing 100-500 kHz range won't be a snap. It doesn't mean it's impossible, but haven't seen such solution on this forum.
May I ask what is application for such lock-in? Maybe other solutions using PSoC are available.
/odissey1
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I want to built an impedance analyzer. I can see that the mixer, can take frequency up to 500kHz.
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JaRa,
Please note that PSoC analog Modulator only inverts signal amplitude (+A/-A), it is not an analog multiplier.
Also Analog Devices recently ran advertisements here for their Zero-IF radios. These are essentially high-frequency lock-in amplifiers.
I recommend reading this paper re lock-in detection first (copy attached)
Synchronous Detectors Facilitate Precision Low-Level Measurements | Analog Devices
https://www.edn.com/design-a-dsp-lock-in-amplifier-part-2-design-methodology/
The impedance analyzer project by Chris Keeser was posted on the forum long time ago. It basically used 1kHz sine for excitation, and DelSig_ADC built-in modulator to demodulate the feedback signal. Since only one DelSig_ADC is available on PSoC5, the in-phase and quadrature measurements were taken separately.
You can find basic lock-in detector project using DelSig_ADC below. I am not sure how much up in frequency it can go. I tested it up to 10kHz, but the modulator "might" work at 100-500k.
Re: PSoC Today! - Synchronous Detection Detail
/odissey1