Abstract: A picture display system in which a picture in the high definition television system is converted into a picture in the conventional television system is provided. The picture display system samples a desired part of picture in the high definition television system, converting a high definition video signal which forms the sampled desired part of the picture into a conventional video signal in the conventional television system, and displays the conventional video signal. The picture in the high definition television system may be divided into a plurality of desired parts, each of which is converted into a conventional television signal. Each of the plurality of desired parts is subsequently displayed on conventional televisions which are arranged to form a single large picture as a whole.

Abstract: A scanning line converting system comprises down-converters arranged in parallel for converting an input high definition television signal to a current television signal, and double-frequency converting sections for respectively doubling the frequency of the down-converted current television signals, for synthesizing them, and for delivering the synthesized signal as a non-interlaced video signal. The non-interlaced video signal can be obtained by properly controlling a vertical filter which is a part of the down-converter with no additional interlace/non-interlace converting unit.

Abstract: An improved clock circuit in which a counter can begin its counting operation following the release of the reset signal always within one-half of the period of the input clock signal. The input clock signal is applied through a D-type flip-flop to one input of an exclusive-OR gate, and to the other input of the exclusive-OR gate directly. The output of the exclusive-OR gate drives the clock input to the counter. The clock input to the D-type flip-flop is supplied by the reset signal.

Abstract: A remote line monitoring device and method for a CATV system in which a center facility is connected to plural terminal units through cables of the system to transmit television signals to subscribers' homes. A plurality of monitoring terminal units are provided along various points of the interconnecting cables. Each of the monitoring terminal units is identified by an unique address. To determine conditions throughout the system, a central monitoring system transmits polling signals on the cables. If an address contained within the polling signals matches with a prestored identifying address, a monitoring terminal unit responds by transmitting data produced by monitoring converter units back to the center facility. The center facility can then display the data or produce indications identifying problems along the cables.

Abstract: A line monitoring device for use in a two-way data communication system such as a CATV system in which up-signals are transmitted by terminal units in response to retrieving signals applied thereto from a central facility to monitor the levels produced by the various terminal units. An address detection signal compares the address number included in a polling down-signal from the central facility with an address prestored in the monitoring device. A response signal detection section detects the up-signals from the terminal units. A display section operates in response to the address detection section to display the level of an up-signal from a terminal unit as produced on the output of the response signal detection section when the address received from the central facility coincides with the pre-stored address.

Abstract: In a CATV system, channel identifying data is incorporated in each transmitted channel, and subscriber terminals return such data to the CATV center to indicate the channel actually being received. Further, the channel identifying data is compared to the channel selected, and when a proper comparison exists a sweep voltage is held at a predetermined level for the particular channel, to control frequency conversion at the terminal.