Signal Processing And Compensation Electronics For Junction Field-Effect Transistor (JFET) Focal Plane Arrays

A signal processing system has been designed and constructed for a pyroelectric infrared area detector which uses a matrix-addressable JFET array for readout and for on-focal plane preamplification. The system compensates for all offset and gain nonuniformities in and after the array. Both compensations are performed in real time at standard television rates, so that changes in the response characteristics of the array are automatically corrected for. Two-point compensation is achieved without the need for two separate temperature references. This paper describes the focal plane circuitry used to read out the array, the offset and gain compensation algorithms, the architecture of the signal processor, and the system hardware.