Lock-in Amplifiers

Lock-in-amplification is a useful technique to remove unwanted noise allowing reliable operation in electrically noisy environments. Phase, gain and time constant are controlled either by switches on the amplifier module or externally using standard digital I/O computer board. The frequency can be set by an external reference signal that can be synchronised with a chopper wheel or the modulation signal of a laser. The input signal can be a current or voltage, making the amplifier suitable for high impedance sources like photodiodes or PMTs, low impedance sources like pyros or coils.