The EG&G 5301 Lock-In Amplifier 2 Hz - 210 kHz combines proven analog techniques of signal recovery with digital microprocessor control. Includes a 5317 Differential Preamplifier. It features two-phase operation, multi-function signal channel, automatic tuning, automatic phasing, auto measure, and improved low frequency operation. Provides linear, exponential & sliding point averaging and also does internal computations and internal curve storage. Includes built-in computer control plus IEEE-488 interface as well as an internal oscillator.