Remote volume control for radio receivers - brackets important broadcasts by frequency modulation of basic tone in order to give high volume

摘要

The remote volume control, for radio receivers, allows certain transmissions (e.g. traffic information warnings etc.,) to be broadcast in such a way that they are reproduced at the receiver with a volume greater than normal -- thereby attracting the attention of the listener (and also receiving hind of the tiresome effort of listening to programmers for which he has no interest just to hear e.g. traffic information). The traffic broadcast is bracketed between two signals represented by alternate jumps in the frequency of a basic tone and at a rate less than the basic tone frequency. The start and stop bracket signals differ in frequency sweepby double demodulation. The last demodulator causes changes in the receiver volume.