JPH0690413A - Television receiver - Google Patents

Abstract

PURPOSE:To correctly detect the position of an RF signal with a simple constitution to skip this position at the time of using channel up and down keys for channel selection by constituting the television receiver so that channels, which are selected in the case that the same phase is not detected by phase comparison, are skipped at the time of channel selecting operation. CONSTITUTION:A detection signal 13 obtained by a tuner circuit 5 is allowed to pass a synchronizing signal separation circuit 4, and phases of an obtained synchronizing signal 10 and a flyback H pulse signal 11 outputted from a flyback transformer 6 are compared with each other by a signal detecting circuit 3. Signal presence is discriminated when they have the same phase, but signal absence is discriminated when phase comparison is impossible because of the absence of the synchronizing signal 10, noise, or the like; and signal presence/absence information is outputted to a microcomputer 2 as a signal presence/ absence signal 9. When the microcomputer 2 is operated by the operation of a channel up/down key 1 for channel selection, it is determined in accordance with contents of the signal presence/absence discrimination signal 9 whether the position should be displayed or skipped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input and received by a television receiver.

[0002]

2. Description of the Related Art In a conventional television receiver, regardless of whether a channel stored in a position is receiving a broadcast signal, that is, an RF input signal, all channels can be operated by operating a channel UP or DOWN key. The position is displayed on the screen in order.

Next, the operation will be described. Conventionally, when the number of channel positions that can be stored is 5, and a channel is selected, by pressing the channel UP key once, the RF signal for each position is 1 → 2 → 3 → 4 → 5 → 1. Be sure to display all positions regardless of the presence or absence of. When the channel DOWN key is operated, the operation is the reverse of when the channel UP key is pressed.

[0004]

Since the channel selection of the conventional television receiver is configured as described above, since all positions are displayed regardless of the presence or absence of the input signal, the position without RF signal is displayed. When it changes to, there is a problem that the viewer is uncomfortable and the number of unnecessary operations is increased because the snow noise is displayed.

The present invention has been made in order to solve the above problems, and when a channel UP or DOWN key is used for channel selection, it is possible to use a simple structure for R
It is an object of the present invention to obtain a television receiver in which a position with no F signal is accurately detected and the position is skipped.

[0006]

A television receiver according to the present invention comprises a selecting means having a channel selecting function, a means for extracting a synchronizing signal from a video signal, and a synchronizing signal from the extracting means from a flyback transformer. It is provided with comparing means for phase comparison with the output signal to be output, and when the channel selecting operation is performed by the selecting means, the selected channel is skipped when the phase comparison by the comparing means is not the same phase. ing.

The television receiver according to the second aspect of the invention is provided with external image input switching means as selecting means.

[0008]

In the television receiver according to the present invention, the synchronizing signal of the video signal of the selected channel and the output signal output from the flyback transformer are phase-compared with each other, and when the phase is not the same, the selected channel is skipped.

Also, the television receiver according to the second aspect of the present invention compares the phase of the synchronizing signal extracted from the selected external image input with the output signal output from the flyback transformer, and selects when they are not in phase. External video input is skipped.

[0010]

EXAMPLES Example 1. FIG. 1 is a block diagram showing a first embodiment of the present invention. In the figure, 1 is a channel U
P, DOWN key, 2 judges the position of signaled or not signaled, and decides whether to display the position or jump (microcomputer) (3) signal detection circuit, 4 sync separation circuit, 5 A tuner circuit, 6 is a flyback transformer, and 7 is a video processing circuit.

Next, this operation will be described. The detection signal 13 obtained by the tuner circuit 5 is passed through the sync separation circuit 4. The signal detection circuit 3 compares the phases of the synchronization signal 10 obtained therefrom and the flyback H pulse signal 11 output from the flyback transformer 6. As a result, if they are in phase, if there is no signal, or if there is no sync signal 10 or if the phases cannot be compared due to noise, then no signal is output, and information on the presence or absence of a signal is output as a signal presence / absence determination signal 9 to the microcomputer 2. input.

Channel U is used to select a channel.
When the P or DOWN key is operated, the microcomputer operates to change the position. At this time, depending on the content of the signal presence / absence determination signal 9, it is determined whether to display the position or jump. That is, when the number of channel positions is 5,
Currently, the channels stored in positions 1, 3, 4, and 5 are broadcast, and when the channel stored in position 2 is not broadcast, operating the channel UP key will skip position 2 ,
The position changes in the order of 1 → 3 → 4 → 5 → 1.

In this embodiment, the microcomputer is used as the channel selecting means and the sync separation circuit is used as the means for extracting the sync signal, but other means may be used.

Example 2. In the first embodiment, the TV mode for receiving the RF signal is used as an example, but in the second embodiment, an example applied to an external video input (hereinafter referred to as AV input) is shown. Equipped with multiple AV inputs, press the AV switch key to switch from TV to A
Even if the video input source can be selected as in V1 → AV2 → ... → BS (satellite broadcasting) → TV, the presence or absence of a signal at each input unit is determined as in the case of the first embodiment, and the signal is input. Not input can be skipped.

[0015]

As described above, according to the present invention, when a channel UP, DOWN key or AV switching key is operated, a channel having no video signal can be accurately skipped by a simple structure, so that the viewer is prevented from snow noise or the like. There is an effect that it is possible to provide a television receiver at low cost that eliminates uncomfortable viewing and unnecessary operation on the screen.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the present invention.

[Explanation of Codes] 1 channel UP, DOWN key 2 Microcomputer 3 Signal detection circuit 4 Sync separation circuit 5 Tuner circuit 6 Flyback transformer 7 Video processing circuit 8 CRT 9 Signal presence / absence determination signal 10 Synchronization signal 11 Flyback H pulse signal 12 selection Station signal 13 Detection signal

Claims (2)

[Claims] 1. A selection means having a channel selection function,
An extracting means for extracting a synchronizing signal from the video signal; and a means for comparing the synchronizing signal from the extracting means with the output signal output from the flyback transformer in phase, and when selecting the channel by the selecting means, A television receiver characterized in that the selected channel is skipped when the phase comparison in said comparison means is not in phase. 2. The television receiver according to claim 1, further comprising an external image input switching means as the selecting means.