| 摘要 |
Device for the simultaneous transmission between a transmitter and at least one receiver within a predetermined frequency band of a modulated analogue electromagnetic signal carrying a first item of information and possibly occupying the entire band and of a digital or analogue signal carrying a second item of information, of the type including, in the vicinity of the transmitter, a source of an analogue signal and a generator of a signal with a predetermined frequency, controlled as a function of the state of the digital signal to be transmitted produced by a control interface characterised in that it moreover includes, in the vicinity of the transmitter E between the source 1 and the said summing unit 9, a low-pass filter 2 whose cutoff frequency is below the said frequency F, a first switching circuit 3 enabling the said filter 2 to be cut in and out of circuit, a second switching circuit 8 inserted between the said generator 6 and the said summing unit 9, a control circuit 4 driven by the said control interface 7 and which controls the said first and the said second circuit in synchronism. <IMAGE>
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