A lock-in amplifier (also known as a phase-sensitive detector) is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment (S/N ratio can be -60 dB or even less). It is essentially a homodyne with an extremely low pass filter (making it very narrow band). Lock-in amplifiers use mixing, through a frequency mixer, to convert the signal's phase and amplitude to a DC-actually a time-varying low-frequency-voltage signal.
The device is often used to measure phase shift, even when the signals are large and of high signal-to-noise ratio, and do not need further improvement.
Recovering signals at low signal-to-noise ratios requires a strong, clean reference signal the same frequency as the received signal. This is not the case in many experiments, so the instrument can recover signals buried in the noise only in a limited set of circumstances.
The lock-in amplifier was invented by Princeton University physicist Robert H. Dicke who founded the company Princeton Applied Research (PAR) to market the product.Lock-In Amplifier
This model is: SR830 Dual Phase Lock-In Amplifier
Current Location: 36-228
Vendor: Stanford Research Systems
Manual: Instruction Manual
Specifications: Datasheet
LabView Programs: Available
Price: $4500
Purchase Date: 10-3-2008