Societa Italiana Telecomunicazioni Siemens S.p.a.

Giovanpietro Bassani

Giuseppe Scozzari

Gianfranco Marchetti

A cable-TV system comprises a relay station linked by several HF cables with a distribution center feeding several subscriber stations via two-wire local lines, each HF cable carrying a respective TV program modulated on a common carrier. The distribution center comprises several switching matrices which are remote-controlled from respective subscriber stations for transmitting selected programs to any of them. Each subscriber station includes for this purpose a generator of a carrier frequency, above the band of incoming frequencies, which is pulse-modulated with the aid of a keyboard to identify the desired programs and is demodulated at a control unit tied to the associated switching matrix at the distribution center.

Cable distribution system for wide-band message signals

An integrated circuit for the selective completion and interruption of a signal path comprises three transistors of the MOSFET type, i.e., a switching transistor in tandem with a decoupling transistor and a pilot transistor in cascade with the switching transistor. The channels of the switching and decoupling transistors lie in series between supply terminals of opposite potential, together with a load resistor. The channel of the pilot transistor is connected across the same supply terminals by way of a biasing resistor tied to the gate of the switching transistor. On/off voltages are applied to the gate of the pilot transistor while incoming signals are fed to the gate of the decoupling transistor.

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Milan, Italy

Giovanpietro Bassani