Digital data diversity radio broadcasting system - includes in transmitted signals enabling car radio to re-tune automatically to alternative frequency if signal fades

摘要

Incorporated in the broadcast signal is a repeated digital signal which can be interpreted as a physical matrix showing the relative positions of transmitters which carry the same programme. The signal from the aerial (A) is fed via an r.f. amplifier (1) to the frequency synthesis tuner (2). The signal is then fed via the i.f. system (3) and frequency detector (4) to the stereo demultiplexer (5) and thence to the loudspeakers (6). The detected signal is also fed to an RDS decoder (8) which provides fault correction facilities and the alternative frequency matrix data. The data, which are demodulated from its 57 kHz carrier, are then fed to an auxiliary microcomputer (9) which has an auxiliary memory (10). The main microcomputer (11) produces a signal which is fed back to the digital tuning input (7) to control the reception frequency.