The 5301 Two-Phase Lock-in Amplifier combines proven analog techniques of signal recovery with digital microprocessor control. Includes a 5316 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. It has three 3.5 digit displays which are used to display many of the parameters being measured or set, and has bandwidth of 2Hz to 210kHz, input sensitivity of 100 nV to 500 mV full scale and input impedance of 100 Mohms/15 pF. Common mode rejection at 60Hz >100 dB.