There is disclosed a wired television system comprising a source of television signals supplying signals to a transmission network, subscriber stations connected to the network, means for preventing reception of transmitted signals by at least one subscriber station, and means for overriding the preventing means to enable that subscriber to receive the transmitted signals. The television signals are heterodyned with a scrambling signal to provide the transmitted signals, and the scrambling signa...

The present invention comprises a method of transmitting information from a central ground station to at least one mobile auxiliary ground station via at least one base station. The auxiliary ground stations are located within the transmitting range of at least one base station, and are provided with a receiving device having a control unit and a memory. In accordance with this method, a block of messages cyclically repeated within a time frame is transmitted over a single frequency from the cen...

In a broadcasting satellite, signals transmitted through an up transmission line of a Ka band, which includes a plurality of communication channels, are received by a Ka-band antenna. The signals received by the antenna are passed through band-pass filters to thereby extract a broadcasting signal transmitted through each communication channel. Those of the thus-extracted broadcasting signals, which have been transmitted through predetermined communication channels, are synthesized by each of syn...

A video broadcasting method and apparatus. The broadcasting method generally includes the steps of selecting one or more channels from a plurality of available channels, and scanning the selected channels for generating signals identifying these selected channels. The channel identifying signals are then fed back to a transmitter unit over a first carrier frequency. The feedback signals are used to selectively identify the channels to be transmitted. The signals from the selected channels are co...

A system for broadcasting data makes it possible to broadcast facsimile d toward a plurality of telecopying apparatuses, using an asynchronous broadcasting network. To each telecopying device there is joined a reception juncture device which develops a going time base or clocking to synchronize the telecopying device. At the emitting station, an emission juncture device simulates the operation of a reception juncture device to govern the transmission of the signal by the network.

A wired broadcasting system operates with several transmitting program sources and a program exchange which couples a subscriber's twisted pair cable connection to a selected one of the sources. A separate set of control signal conductors enable the subscriber to select either a program source or another subscriber's station.

A direct broadcasting satellite receiver including an indoor unit for receiving a broadcasting wave transmitted from a stationary artificial satellite through an antenna installed outdoors, a signal input terminal provided at the indoor unit to which the output signal from the antenna is supplied through a signal cable, a demodulating circuit for demodulating the input signal at the input terminal into a television signal, a level detecting circuit for resultantly detecting the signal level at t...

A wired television broadcasting system using television receivers designed for aerial reception has specific frequencies for vision and sound carriers to place the beat therebetween at a frequency rejected by the adjacent channel sound rejection characteristics of the television receivers.

An AM stereo broadcasting system for transmitting stereo signals in the AM broadcasting band. The system is based on amplitude modulation by two carriers having the same frequency and a 90.degree. phase difference from each other, and is capable of increasing the modulation depth of pilot signals (used for stereo signal identification) irrespective of the stereo signals, so that the pilot signals can be easily detected. By modulating both the sum and difference signals by the pilot signal, the r...

A receiver for a composite signal consisting of video and audio multiplex signals intermittently transmitted in a predetermined sequence and having synchronizing signals with a blanking period and different repetition frequencies in the video signal period and the audio multiplex signal period, wherein the synchronizing signals are so composed as to have an identical mode at least for a part thereof at a common measure frequency of the two different repetition frequencies. The receiver comprises...