ULTRA LINEAR RAMP GENERATOR FOR SLIDING PULSERS

A ramp generator has been developed for use with voltage sampling pulse generators thereby providing pulses the amplitudes of which increase linearly with time (sliding pulser). The basic circuit of the ramp generator is an operational integrator which includes a high gain (∼ 108) chopper-stabilized amplifier and an integrating capacitor with polystyrene dielectric. The output voltage of the generator is a sawtooth with selectable ramp slopes of 0.01, 0.1 and 1.0 V/sec. Other features include 1) selectable ramp polarity, 2) adjustable ramp amplitude, 3) single or repetitive sweeps, and 4) an end-of-ramp pulse. The change in slope over 85% of the 10 V ramp is less than ±0.01% and over 55% of the range the incremental non-linearity is less than ±0.005%. The main contributors to the ramp non-linearity are dielectric absorption in the integrating capactior, and change in capacitance as a function of the applied voltage. The incremental and differential linearity measurements and the design considerations are discussed. © 1969.