Digital transmission frequency discriminator - has input gated to counter and resulting count value compared with reference for subsequent integration

摘要

The numerical discriminator for transmission frequencies has the digital input signal (S(f) applied via a switch (TS) to a counter (ZR) whenever the switch is closed by a reference signal (S(fb). A comparator (AS) compares the output of the counter with the ref. signal at the end of each counting period to produce either a positive or a negative pulse. This pulse is integrated to give a dc level.