Hi Everyone, I am trying to get a 1kHz small signal from buries of noises. And a lock-in amplifier has been chosen. I have some questions on using lock-in Amps.
1. The last stage of a lock-in amplifier is a low-pass filter or an integrator. What is the exact difference of using these two components?
Could I say that the integrator is more accurate, since the output is measured by counting time needed to discharge the capacitor (you can visit http://cappels.org/dproj/syncdet/syncdet.html for more information), which means the result is time-averaged.
If I use a low-pass filter, the result is just measured by, say ADC instantly. Could the measured result represent the real value? Or may I ask, if the lock-in amplifier is trading time for accuracy, what is the minimum time required to measure a 1kHz signal accurately?
2. The amplifier will mix a synchronized signal with the measured signal. Could I just use switches? What are the differences of mixing signal with sine wave or with pulses?
Thank you very much. Any idea will be highly appreciated. )
1. The last stage of a lock-in amplifier is a low-pass filter or an integrator. What is the exact difference of using these two components?
Could I say that the integrator is more accurate, since the output is measured by counting time needed to discharge the capacitor (you can visit http://cappels.org/dproj/syncdet/syncdet.html for more information), which means the result is time-averaged.
If I use a low-pass filter, the result is just measured by, say ADC instantly. Could the measured result represent the real value? Or may I ask, if the lock-in amplifier is trading time for accuracy, what is the minimum time required to measure a 1kHz signal accurately?
2. The amplifier will mix a synchronized signal with the measured signal. Could I just use switches? What are the differences of mixing signal with sine wave or with pulses?
Thank you very much. Any idea will be highly appreciated. )