DEVICE FOR DISCONNECTING THE RECEIVER IN CASE OF A SMALL SIGNAL-TO-NOISE RATIO FOR A DIGITAL-MODULATED RADIO SYSTEM

摘要

ABSTRACTRapid disconnection of a receiver in response to a small signal-to-noise ratio is provided in that in the receiver there is arranged a FSKdemodulator having two channels connected in parallel at the input ends andeach having a band-pass filter, an amplifier and a detector whose output isconnected to a voltage comparator. The output signal of the voltage compara-tor is fed to an input of an AND gate in the receiving arm by way of a seriesarrangement of a high-pass circuit, a demodulator and a low pass filter tothe inverting input of a further comparator whose non-inverting input isconnected to a comparison voltage by way of a variable voltage divider. Theoutput of the further comparator is connected to the other input of the ANDgate.