Lock-in Amplifier

State of the art optoelectronic systems utlise lock-in-amplification as one of the most useful techniques to remove unwanted noise and so improve measurement sensitivity. These miniaturised, powerful modules operate reliably even in extreme electrically noisy environments. Phase, gain and time constant are controlled either by switches directly on the amplifier module or externally using a standard digital I/O computer board. The variable working frequency is determined by an external reference signal that may be a synchronised signal of a chopper wheel or the modulation signal of a laser. The current input is well suited for amplifying signals from high impedance sources like photodiodes or PMTs while the voltage input can be used to measure signals from low impedance sources like pyros or coils.