JPH08336079A - Automatic channel changeover device - Google Patents

Abstract

PURPOSE: To obtain an automatic channel changeover device suitable for a television receiver installed on a street or the like by preventing that the television receiver is left with ungainly screen when a reception state of a television broadcast is not excellent or the broadcast is finished. CONSTITUTION: Whether or not a synchronizing signal is in existence in a channel being received is checked and when the synchronizing signal is in existence, a microcomputer 4 outputs a channel selection signal being received at present to a tuner 2 continuously and when no synchronizing signal is in existence, a selection signal of another channel is outputted to the tuner 2. Thus, when the reception state is not excellent or the broadcast is finished, a channel with excellent reception state or a channel broadcasting a program is selected automatically and when the broadcast of all channels is finished, power is interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic channel switching device for automatically switching television channels.

[0002]

2. Description of the Related Art Conventionally, channel switching of a television is performed by a user operating a key of a remote controller or an operation button of a television main body, and when the channel broadcasting being received is finished, the power of the television set is turned off. , I was manually switching to another live channel. In addition, when the broadcast ends, some TV sets are automatically turned off.

[0003]

However, in such a conventional TV set, for example, a TV set exhibited at a store for demonstration is often left in a poor reception state. ,unsightly. Also, in a TV set etc. installed on the street, if it operates to automatically turn off the power when the broadcasting of the channel being received is finished, it can be left in the receiving state There is no problem, but in a TV set that is not set to automatically turn off the power, it cannot be left unattended, and therefore unattended reception for a long time has a difficulty. The present invention has been made to solve the above-mentioned problems, and when the reception condition is not good or when the broadcasting of the channel being received is finished, another channel with a good reception condition is automatically selected. Switching, and when the broadcasting of all channels is finished, the power of the TV set is automatically turned off,
It is an object of the present invention to provide an automatic channel switching device that enables unmanned reception for a long time.

[0004]

In order to achieve the above object, an automatic channel switching device according to the invention of claim 1 is an automatic channel switching device for automatically switching a television channel, which receives a television broadcast wave. Tuners that perform tuning operations, and the TV broadcast waves received and tuned by the tuners are processed into audio and video signals,
And, based on the signal from the signal processing circuit that detects the synchronization signal and the synchronization signal detection output terminal of this signal processing circuit, the presence or absence of the synchronization signal for the channel currently being received is checked, and when there is the synchronization signal, A microcomputer is provided which continuously outputs the channel selection signal currently being received to the tuner and outputs a channel selection signal for selecting another channel to the tuner when there is no synchronization signal. Further, in the automatic channel switching device of the invention of claim 2, in the structure of claim 1, when the microcomputer detects that there is no synchronization signal for all channels, the power of the television is turned off.

[0005]

In the automatic channel switching device according to the first aspect of the present invention, the signal processing circuit detects the synchronizing signal contained in the television broadcast wave tuned and tuned by the tuner. The output level at the sync signal detection output end of the signal processing circuit changes depending on whether or not the sync signal has been detected. The microcomputer checks the presence / absence of a sync signal based on the level of the sync signal detection output end for the channel currently being received, and if there is a sync signal, continuously outputs the channel selection signal currently being received to the tuner. If there is no sync signal, a channel selection signal for selecting another channel is output to the tuner. As a result, when the broadcast of the currently received channel is completed or when the reception state is not good, the channel is automatically switched to another channel. Further, in the automatic channel switching device according to the second aspect, the power of the television is turned off when the microcomputer detects that there is no synchronization signal for all channels.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an automatic channel switching device according to this embodiment. As a constituent element of a television equipped with an automatic channel switching device, the illustrated automatic channel switching device 1 that automatically switches channels
In addition to (hereinafter referred to as switching device 1), CR for video output
It has a T display, a speaker for voice output, and the like. The switching device 1 includes a tuner 2 that receives a television broadcast radio wave and performs a tuning operation, and a circuit that processes the television broadcast radio wave received and tuned by the tuner 2 into an audio / video signal, and the processed signal. The signal processing circuit 3 for detecting the synchronizing signal in the inside and the channel selection for the tuner 2 based on the signal whether or not the synchronizing signal from the station detector terminal SDOUT which is the synchronizing signal detecting output end of this signal processing circuit is detected. A microcomputer 4 that outputs a signal (hereinafter, abbreviated as microcomputer 4) is provided.

In the microcomputer 4, the station detector terminal SDOUT of the signal processing circuit 3 outputs the capacitors C1 and C.
2, a resistor R1 and R2, and an input terminal H / SYNC that is input via a transistor Q1. Further, the microcomputer 4 has a channel select terminal C / S for outputting a channel selection signal to the tuner 2 and a microcomputer. 4 and tuner 2 are synchronized with a clock terminal CLOCK and a data transmission terminal DATA for outputting various instruction data to the tuner 2.
And have. In addition, as a terminal corresponding to the channel select terminal C / S, the clock terminal CLOCK, and the data transmission terminal DATA of the microcomputer 4, the tuner 2 has a channel select input terminal C / S and a clock terminal CLO.
CK and a data input terminal DATA are provided.
Further, the tuner 2 is a PLL (Phase Phase) which is a detection circuit.
Locked Loop) ・ IC circuit is built in, PLL ・ I
It has an output terminal IF for outputting the intermediate frequency signal of the channel tuned by the C circuit to the input terminal 3b of the signal processing circuit 3.

Next, the operation of the switching device 1 having the above configuration will be described with reference to FIG. FIG. 2 is a flowchart showing the procedure of the channel switching operation of the switching device 1. When the channel selection signal is input to the microcomputer 4 from the remote controller or the key input unit of the television, the microcomputer 4
Channel output signal from tuner to tuner 2 (S
1), the tuner 2 tunes to the frequency of the television broadcast radio wave according to this channel selection signal, and performs automatic frequency adjustment (AF
T) Process is performed (S2). This AFT-adjusted signal is input to the signal processing circuit 3. When the signal processing circuit 3 detects a synchronizing signal, that is, a horizontal synchronizing signal in the input signal, the signal processing circuit 3 outputs a Hi level signal to the station detector terminal SDOUT. When the Hi level signal is output, the transistor Q1 turns on, and the input terminal H of the microcomputer 4
A Lo level voltage is applied to SYNC, whereby the microcomputer 4 detects the presence of a sync signal (S3: YES). Then, the selected channel is received by the tuner 2 (S4), and the presence or absence of the sync signal is constantly checked during reception, and if the sync signal is present (S5: YES), the currently selected channel is continued. It is received (S6), and the process ends.

In S3 and S5, if the signal processing circuit 3 does not detect the synchronizing signal, the Lo level signal is output to the station detector terminal SDOUT. In this case, the transistor Q1 is turned off, and a Hi level voltage is applied to the input terminal H / SYNC of the microcomputer 4, whereby the microcomputer 4 detects the absence of a synchronization signal (S3).
(S5: NO), and when the state without sync signal has passed a predetermined time (for example, several seconds) (S7: YES), the microcomputer 4 selects the next channel (S8), and then selects all the channels. Is checked (S9), and if all the channels have not been selected (S9: NO), the processes from S1 onward are repeated for the next channel. If all channels are selected in S9 (S9: YES), the power is turned off (S1).
0), the process ends.

As described above, in the switching device 1, the signal processing circuit 3 detects the sync signal included in the television broadcast radio wave received by the tuner 2, and the microcomputer 4 causes the sync signal for the channel currently being received. If there is a sync signal, the channel selection signal currently being received is continuously output to the tuner 2, and if there is no sync signal,
Since a channel selection signal for selecting another channel is output to the tuner 2, for example, even if the television is left on display for demonstration at the store, the channel is automatically switched when the reception condition is not good. It is possible to perform unmanned reception for a long time in a street or the like without causing an unsightly appearance of a channel that is not being broadcast on the screen.

Further, when it is detected that there is no sync signal for all channels, the power of the television is turned off, so that an unsightly screen at the end of broadcasting is kept output and unnecessary power consumption is suppressed. This can be done, and the power will not be turned off despite broadcasting on another channel.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above-described embodiment, the horizontal synchronizing signal is detected to determine whether or not the channel is being broadcast, but the vertical synchronizing signal may be detected. Further, the elapsed time of S7 for determining whether or not there are these synchronization signals may be arbitrarily selected.

[0013]

As described above, according to the automatic channel switching device of the first aspect of the present invention, the synchronizing signal is detected from the television broadcast radio wave received by the tuner by the signal processing circuit, and the channel currently being received is When it is detected that there is a sync signal, the channel currently being received is continued, and when no sync signal is detected, another channel is selected, so the currently received channel is broadcast. When the channel is finished or when the reception condition is not good, the channel is automatically switched to another channel having a good reception condition. Therefore, it becomes possible to perform unmanned reception for a long time on the street and the like. According to the automatic channel switching device of the second aspect of the present invention, the microcomputer turns off the power of the television when it detects that there is no synchronization signal for all channels. It does not happen and the power is not turned off when it is detected that there is no sync signal for only one channel.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an automatic channel switching device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of the automatic channel switching device.

[Explanation of symbols]

 1 Automatic channel switching device 2 Tuner 3 Signal processing circuit 4 Microcomputer SDOUT Station detector terminal H / SYNC input terminal

Claims (2)

[Claims] 1. An automatic channel switching device for automatically switching a television channel, wherein the tuner receives a television broadcast wave and performs a tuning operation, and the television broadcast wave received and tuned by the tuner is converted into an audio / video signal. A signal processing circuit for processing and detecting a synchronization signal, and based on the signal from the synchronization signal detection output end of the signal processing circuit, checks whether or not there is a synchronization signal for the channel currently being received, and there is a synchronization signal. And a microcomputer that outputs the channel selection signal currently being received to the tuner continuously, and outputs the channel selection signal to select another channel to the tuner when there is no synchronization signal. Characteristic automatic channel switching device. 2. The automatic channel switching device according to claim 1, wherein the microcomputer turns off the power of the television when it is detected that there is no synchronizing signal for all channels.