The 126 Lock-In Amplifier is a high-performance amplifier or phase sensitive detector, incorporating synchronous detection to recover a coherent signal buried in high ambient noise levels. It utilizes plug-in preamplifiers that permit matching to a wide range of source impedances. The signal channel will accept signals over a frequency range of 0.2Hz to 210kHz. Sensitivity is in 18 full scale ranges in 1-2-5 sequence.