Funai Electric Company Ltd.

Shigeto Sakakibara

Katsuhiro Morisada

Hiroki Nakamura

Yoshihiro Yamanishi

Kazumi Notomi

A receiver includes a CPU. The CPU, when executing preset registration, in step Sfirst searches for the presence or absence of receivable channels. If there are receivable channels, received data (center frequency, etc.) is registered in step S. If the received channel is a TV channel, filtering is carried out in step Sto count only the channels existing within a range of &#xb1; approximately 200 kHz of a center frequency. If it is a CATV channel, counting is further made in step Son the channels existing within the range of &#xb1; approximately 200 kHz of the center frequency, and a filter process is carried out in order to remove the channels within the range of &#xb1; approximately 200 kHz of the center frequency +2 MHz of a CATV UHF-band channel overlapped with a TV channel.

Receiver having a preset tuner

A microcomputerdiscriminates a CATV channel plan mode only if there is a continuous channel among the channels that have been judged that station is present as a result of determination in the case where the count number for a TV channel plan is smaller than the count number for a CATV channel plan. However, in the case where there is no continuous channel among the channels that have been judged that station is present, the microcomputeralso discriminates a CATV channel plan mode if there is a continuous channel among the channels of the error data as a result of determination. That is, even when a station adjacent to the normal broadcasting channel is falsely tuned owing to spurious reception, the continuity of the CATV channel can be judged normally.

Television receiving apparatus

A microcomputer searches all the frequency bands included in each of the channel plans for TV and CATV almost continuously, determines whether or not there is a broadcasting station in the channel frequencies assigned to each of the channel plans, judges whether or not the channel frequency of a station that is judged to be present is within a fixed frequency range from the center frequency, and counts up the station present channel number for the channel plan to which the station belongs, if the station is within the fixed frequency range from the center frequency, for all the stations that are judged to be present. And a comparison is made between the counted TV channel number and the counted CATV channel number. If the TV count number is greater than the CATV count number, a TV mode is discriminated, while if the TV count number is smaller than the CATV count number, a CATV mode is discriminated.

A television receiver, in which if a tuner can receive a signal of the television broadcast form of either television wave broadcasting or CATV broadcasting, a microcomputer executes channel preset processing so that signals of television wave broadcasting can also be received although the processing is predicated on CATV broadcasting, then determines signals of which television broadcast form can be received. If the microcomputer determines that the signals of the television wave broadcasting can be received, it makes a reference to the memory positions of the preset contents. To cause the tuner to receive a station-existing channel, the microcomputer matches the target memory position with the channel of television wave broadcasting for receiving the channel.

Television receiver for receiving two different broadcast forms

In effecting channel preset, a microcomputer first determines whether or not a broadcasting is on the air on the basis of the presence or absence of a horizontal synchronizing signal obtained through synchronizing separation by a video IC, and if it is thereby determined that the broadcasting is on the air, received broadcasting signal is pulled into a normal tuning point on the basis of an AFC voltage from the video IC, whereupon the corresponding channel is stored if a vertical synchronizing signal from the video IC can be detected at the normal tuning point. Therefore, it is possible to provide a channel preset device which is capable to detecting an on-air channel more reliably and storing the same without adding special circuitry and the like.

Channel preset device

A television signal tuning device having a memory which is adapted to store central frequency data for starting a synchronizing-signal detecting operation for all the channels and frequency division ratio data thereof. In a data presetting operation for each of the channels, a CPU causes a phase-locked loop circuit to perform a phase-locking operation for every data piece of the central frequency data or frequency division ratio data thereof which are stored in the memory for each channel. When the CPU detects a synchronizing signal from a video signal processing circuit in any one of the phase-locking operations which are successively performed by the phase-locked loop circuit, the CPU immediately renews the channel number and the tuning data thereof in the memory without performing the detection of an AFC variation. This feature greatly reduces the period of time required for the data presetting operation for each channel.

Television signal tuning device

This invention is to provide a method for tuning the channel of a broadcasting wave which is able automatically to secure specified band zone and to shorten the time required for tuning. Namely, this method is characterized by starting the PLL tuning by applying the data of the center frequency of either the first channel plan memorized in advance in tuning the channel of broadcasting wave or the second channel plan differing from the allocation of frequencies for said first channel plan, and by judging whether said broadcasting station belongs to either the first channel plan or the second channel plan by applying the tuned frequency at the time that said tuning is finished, and further by renewing said memorized data of the center frequency according to said judged result.

Method for tuning the channel of broadcasting waves and identifying

An automatic receiving channel setting method of the receiver having a receivable signal strength, judges whether or not the detected channel is included within the frequency zone allotted only to the CATV, sets the receiving mode, and searches and memorizes the channel according to the allotted channel plan of the CATV or sets the receiving mode of the receiver to the TV receiving mode of the ground wave and searches and memorizes the channel according to the allotted channel plan of the TV broadcast of the ground wave.

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Osaka, Japan

Shigeto Sakakibara