True RC integrators with very large and very small time constants using active control of capacitance and/or resistance

Two novel active RC integrator schemes with time-constant enhancement as well as depletion facility are presented. One of the schemes uses a capacitor multiplication technique for time-constant enhancement; the other uses a negative immittance converter to enhance or lower resistance for integrator time-constant control. Both schemes have been tested and the results are found to corroborate the theoretical values. Pertinent discussions relating to their performance have been appended.>