Method and arrangement for transmitting coded information by radio channel in superposition on a traditional frequency modulation transmission

Abstract

Abstract The device comprises an input unit (40) for generating coded information to be transmitted, an FSK coder-modulator (30) for frequency-shift modulation of the coded information to be transmitted, within a frequency range lying between approximately 15 to 18 kHz, a mixer circuit (32) for superimposing, with an attenuation of 20 to 40 dB, the frequency-shift modulated signals on a low-frequency signal of a conventional program which is to be applied to a frequency-modulation radio transmitter (20), a decoder comprising filtering circuits and an FSK demodulator for separating the coded information from the signals delivered by a standard frequency-modulation receiver, and a viewing or recording unit for displaying or recording the filtered and demodulated transmitted coded information. <IMAGE>

Inventors

• 👤 Dimitri Baranoff-Rossine

Bibliographic Details