Oscillator for generating a rechteckfoermigen train of pulses, whose pulse repetition frequency is controllable

摘要

The circuit contains an operational amplifier (V) connected to a capacitor (C); and it includes a FET (FT), a Schmitt trigger (ST), diodes (D1, D2) and resistances (R1, R2). The amplifier and the capacitor (V, C) form an integrator with the integration-time controlled by the FET (FT). The control voltage (A) of zero to -10 V is applied across a switch (P1, P2) between given starting and stopping times. Between switch points (P7, P8), the voltage (B) reaches a threshold e.g. +1.7 V, and between the given times the Schmitt trigger (ST) provides a signal (D) of +5 V, then during a given time this signal drops to zero V. The FET (FT), then discharges the capacitor (C) so that a threshold voltage of +0.9 is reached at a given time. The trigger (ST) is a TTL-gate.