Abstract: A device comprising both a box containing an electronic central unit, and power supply module connected to the central unit. The device also includes an external power supply block connected to the module by an electric cable and provided with both a connection member for connection to a power supply network delivering AC power and a data signal superposed thereon. A converter is provided for converting the AC power. The box includes a carrier current data transmission module, the converter being connected to the connection member and to the electric cable via a first diverter member that extracts and diverts the data signal relative to the converter. The module is connected to the electric cable by a second diverter member for separating the converted power supply current and the data signal and for bringing the power supply current to the power supply module and the data signal to the transmission module.

Abstract: The process is characterized in that the pilot signals (10) generated upstream of the device (11) whose non-linearity it is desired to measure pass through a known non-linear device (15) delivering intermodulation products of known characteristics and in that at least one of the known intermodulation products is harnessed in order to modulate, with the aid of synchronous detection circuits (17), at least one of the signals relating to the components of the intermodulation products of the device to be measured.The applications pertain to the analog transmission of television signals over optical fibers.

Abstract: An amplification circuit comprising a device for compensating for its input current. The amplification circuit includes an amplifier and a capacitor located on the input side of the amplifier. The input-current compensation device consists of a current generator, generating a current Ig, a switch and a device for measuring the average current charging or discharging the capacitor during the time that the switch is open. The current Ig is such that: Average current=Ia-Ig, where Ia is the input current of the amplifier. The value of the average current is close to zero. The value of the current Ig which the current generator must output, so as to make the average current close to zero, is calculated using the device for measuring the average current. The invention particularly applies to a circuit for restoring the DC component of a video signal.

Abstract: A method and apparatus for automatic gain control in a receiver. The input signal to the receiver includes both a DC component and a signal component. Filters are used to separate the two components. The DC component modulates a pilot signal and is then added to the signal component. The combined signal is then amplified to produce an output signal. The output is also filtered and subjected to a synchronous detector to produce a gain control level for the amplifier. The synchronous detector utilizes the filtered output signal to modulate the same pilot signal which is then compared to a reference voltage.

Abstract: A transmission method and a transmitter and receiver Structure is disclosed which provides for transmission of modulated waves using long pulses with a plurality of frequencies. The method involves two consecutive frequencies being separated by 1/T, where T is the period of the useful transmission intervals. The method and the apparatus are particularly suited to broadcasting and reception of television and radio signals as well as telephone communications between exchanges and between radio telephones and communication stations including terrestrial stations and satellites and local computer networks. Most particularly the method is applicable to high fidelity radio transmissions as well as to high definition television (HDTV).