Device for conveying a high-voltage low-frequency signal over a carrier connection

A device for conveying a high-voltage, low-frequency signal from one end of a carrier connection to the other end in response to a low-frequency signal applied at said one end of the carrier connection, said carrier connection normally transmitting transmission signals between said ends modulating at least one carrier wave, said device comprising:

• a sender part and a receiver part connected together by said connection, the sender part comprising:
• a frequency doubler circuit receiving the low-frequency signal and supplying in response a signal having a frequency twice that of said received signal;
• a rectangular wave forming circuit connected to the output of the frequency doubler circuit and supplying, when the low-frequency signal is applied to said doubler circuit, a rectangular signal having a frequency twice that of the received signal;
• a modulator interrupting said carrier wave at the rate of the low-frequency signal delivered by the rectangular wave forming circuit;
• and said receiver part comprising:
• a detection circuit which is tuned to said carrier wave which is interrupted by said modulator, said detection circuit providing a low-voltage signal corresponding to said low-frequency signal delivered by the rectangular wave forming circuit;
• a divide by two frequency divider circuit connected to the output of the detection circuit and delivering, when a low-voltage signal is received, a rectangular signal having half the frequency as that of the low-voltage received signal and a mark space ratio of one;
• a voltage increasing circuit supplying two DC voltages of opposite signs from at least one voltage which is less than said two DC voltages and applied by a power supply;
• a switch connected to the output of the voltage increasing circuit, controlled by the frequency divider circuit and alternately switching, at the rate of the signal delivered by the frequency divider circuit, each of said DC voltages of opposite signs to the terminals of a line leading to said other end of the carrier connection.