Cordless transmission device adapting method especially to ETSI appropriate frequency band

摘要

The transmission device a modulation stage (3) which uses a low frequency oscillation of a signal source (2) and frequency modulates a high frequency carrier wave (4). The device receives the frequency modulated carrier wave from the transmitter, via a band pass output filter, and feeds it to a demodulator. This extracts the signal from the carrier wave and feeds it to the headphones or loudspeaker (1) via an amplifier (7). The signal amplitude before the modulation stage and/or the quotient of frequency deviation and predetermined signal amplitude is reduced and the amplification factor of the amplifier or the receiver (6) is increased. The frequency of the carrier wave is increased. The frequency and bandwidth of the output filter are then adjusted to the frequency and the maximum permissible frequency deviation of the carrier wave.