FM receiver with high signal=to=noise ratio - detects and demodulates digital-data-carrying signals having pseudo-fire-value levels

摘要

This non-coherent receiver detects, demodulates and decodes FM digital data signals having pseudo-five-value signal levels. The received signal is fed to a combined frequency converting, amplifying and limiting circuit (2). The output of this circuit is fed to a frequency discriminator (3) to recover the base-band signal (4). The base-band signal is fed via a low pass filter (6) that removes all signal components with frequencies higher than the base-band to feeds a level detector circuit (7). The output of the level detector is fed to a decoder circuit (8) that produces the recovered data signals (10). Both the level detector circuit (7) and the decoder circuit (8) are synchronised by a clock pulse generator (9), which is itself triggered by the base-band signal (4).