Digital=analogue conversion circuit - has digital counter which controls feedback path of high gain amplifier

摘要

A frequency-to-voltage converter includes a control circuit (10) to which an input signal of frequency F1 is fed. A clock pulse generator (11) produces a regular train of pulses having a frequency F2. The control circuit is coupled indirectly by way of an AND-gate (17) to a digital counter circuit (13). There is also a direct connection. The clock pulse generator output is applied to the AND-gate. The counter is connected to a memory circuit (14) and thence to a D/A converter (15) which is placed in the feedback path of a high-gain amplifier (16). There is a direct connection between the control circuit and the memory. An analogue signal obtained from the amplifier is proportional to the frequency of the input signal.