| 摘要 |
<p>The device comprises an input unit (40) for generating coded data to be transmitted, an FSK codermodulator (30) for modulating, by frequency shift, the coded data to be transmitted, in a frequency range located between about 15 and 18 kHz, a mixer circuit (32) for superimposing, with an attenuation of 20 to 40 dB, the signals modulated by frequency shift on a low-frequency signal of a traditional program to be applied to a frequency modulation radio transmitter (20), a decoder comprising filter circuits and an FSK demodulator for separating the coded data from the signals delivered by a standard frequency modulation receiver, and a display or recording unit for displaying or recording the demodulated, filtered, transmitted coded data.</p> |
