Voltage-frequency converter with comparator between integrator and output - has feedback contg. digital pulse generator controlled by quartz oscillator

摘要

The comparator (3) between the integrating circuit (2) and converter output (A) generates a rectangular output signal at a frequency dependent on the input voltage (UM) to be measured. This output signal serves to switch a feedback branch supplying the integrating circuit with a feedback current. - The feedback branch contains a digital pulse generator (P) controlled by a quartz oscillator (Q). Upon appearance of either a positive or negative flank of the rectangular output signal, the generator produces a pulse of a constant duration (TL) set by the oscillator. As well as being connected to the input voltage (UM) via a first series resistor (R1), the integrating circuit is also connected to a reference voltage source (UR) via a second series resistor (R2) and a switch (S) controlled by the pulse generator.