KR19980068966A - Channel Tuning Method - Google Patents

Abstract

The present invention relates to a channel tuning method, wherein when tuning a channel in a VS tuning method, after tuning a frequency band corresponding to a reference channel, a predetermined frequency band is set smaller than the frequency band of the next channel. By summing, and repeating the operation of tuning the next channel by adjusting the fine channel from the summed frequency band, it is possible to tune the correct channel more quickly.

Description

Channel Tuning Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel tuning method, and more particularly, to a channel tuning method that enables channel tuning to be performed more quickly and accurately when tuning a channel by using a voltage (VS) tuning method.

In general, a video cassette recorder (hereinafter referred to as a 'VCR') is a composite video signal applied from a tuner that tunes a broadcast signal transmitted through an antenna to a desired channel. Recording function to record the data on a magnetic tape, and a playback function to display a composite video signal recorded on the magnetic tape and display it on a television (hereinafter referred to as a "TV") monitor. .

On the other hand, in the VS tuning method, a channel is sequentially tuned from a broadcast signal in a low frequency band to a broadcast signal in a high frequency band by voltage, and the microcomputer integrates a VS PWM (pulse width modulation) signal and converts it into a DC voltage. The tuner is supplied to the tuner, and thus the tuner tunes the channel according to the change of the DC voltage.

That is, if the video signal is separated from the broadcast signal of the tuned channel and the number of syncs separated from the video signal is included in the number of syncs corresponding to the normal broadcast signal, the PWM signal is gradually increased, and then the local of the tuner is increased. The channel is tuned and stored according to the AFT (auto fine tunning) curve that maintains a constant oscillation frequency, or the PWM is gradually increased by recognizing the AFT high voltage and the channel is tuned to detect and synchronize the channel.

The present invention has been made to solve the above-described problem, an object of the present invention, when tuning the channel of the VS tuning method, it is possible to tune the channel more accurately by searching the channel only in the range that the actual channel can exist. It is to provide a channel tuning method.

According to an aspect of the present invention, there is provided a VS tuning method for tuning a channel by outputting a pulse width modulated signal (PWM), comprising: a first step of tuning a reference channel; A second step of determining whether the reference channel selected in the first step corresponds to one of predetermined preset channels; A third step of outputting a PWM signal obtained by adding a predetermined frequency band to the frequency of the tuned reference channel if there is no designated channel matching as a result of the determination of the second step, and if the designated channel exists; ; A fourth step of sequentially tuning the next channel by sequentially increasing the frequency of the PWM signal of the third step by one step; A fifth step of determining whether the channel selected in the fourth step corresponds to one of preset channels; A sixth step of returning to the fourth step and repeating the step if there is no designated channel that matches the determination result of the fifth step, and determining whether the tuned channel is the last channel among the designated channels if the designated channel exists; A seventh step of returning to the fourth step if the final channel is not the same as the determination result of the sixth step, and repeating the step, and determining whether the tuned channel is the first reference channel if not the last channel; If it is determined that the seventh step is not the first reference channel, after outputting the PWM frequency corresponding to the first channel among the designated channels, the method returns to the fourth step and repeats the above step. A channel tuning method comprising an eighth step is provided.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a block diagram of a channel tuning apparatus according to a preferred embodiment of the present invention.

2 is a flowchart for performing a channel tuning method according to the present invention.

<Description of the code | symbol about the principal part of drawing>

110: key input unit 120: micom

130 tuner 140 IF amplifier

150: image signal processing unit 160: memory

Hereinafter, an operation according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a configuration diagram of a channel tuning apparatus according to the present invention, and includes a key input unit 110, a microcomputer 120, a tuner 130, an IF amplifier 140, an image signal processor 150, and a memory 160. It is composed.

The key input unit 110 is composed of key metrics and includes a plurality of keys such as channel selection keys and numeric keys according to channel selection, and applies a key signal corresponding to a user's key operation to the microcomputer 120 to be described later. By using a remote controller that can be input from a remote location, the key signal carried on the infrared carrier wave from the remote controller is detected and output.

At this time, when the signal for the channel selection key and the number key according to the channel selection is output from the key input unit 110, the microcomputer 120 outputs a DC voltage obtained by integrating the PWM signal corresponding to the input channel to the tuner 130. .

Accordingly, the tuner 130 tunes a channel according to the variation of the DC voltage obtained by integrating the PWM signal output from the microcomputer 120 with the broadcast signal received through the antenna, and outputs the frequency of the tuned channel to the microcomputer 120. do.

That is, the microcomputer 120 determines whether the channel frequencies tuned by the tuner 130 are stored in the memory 160 in which the channel frequencies are stored, and the channel frequencies tuned by the tuner 130 are stored in the memory ( If stored in the 160, the microcomputer 120 outputs a PWM signal corresponding to the frequency obtained by adding the preset frequency smaller than the channel bandwidth to the tuner 130 to tune the next channel.

Meanwhile, the IF (intemediate frequency) 140 outputs the broadcast signal of the channel tuned by the tuner 130 to the video signal processor 150 and an audio signal processor (not shown).

Therefore, the image signal processor 150 processes the broadcast signal output from the IF signal processor 140 under the control of the microcomputer 120 and outputs the broadcast signal to a monitor (not shown).

2 is a flowchart for performing a channel tuning method according to the present invention, which will be described with reference to the block diagram shown in FIG.

The microcomputer 120 outputs a PWM signal to the tuner 130 to tune the reference channel in step 210.

At this time, the tuner 130 tunes the broadcast signal received through the antenna to the frequency band of the reference channel according to the PWM signal output from the microcomputer 120, and outputs the frequency of the tuned reference channel to the microcomputer 120.

That is, the microcomputer 120 proceeds to step 220 and determines whether the frequency of the reference channel tuned in step 210 is stored in the memory 160.

As a result of determination, if the frequency of the reference channel tuned in step 210 is not stored in the memory 160, the microcomputer 120 returns to step 210 and repeats from step 210, and the tuned reference channel is stored in the memory 160. In step 230, the microcomputer 120 outputs a PWM signal obtained by adding a predetermined frequency band smaller than the channel bandwidth to the tuner 130.

In this case, the sum of the frequency bands to be summed smaller than the channel bandwidth is, for example, in Europe, for example, 7 MHz in VHF (Very High Frequency) and 8 MHz in UHF (Ultra High Freauency). Is set to 6MHz.

On the other hand, if the set frequency band is too small or exceeds the frequency band range of the used channel, the accuracy and speed of the effect of the present invention will be reduced. It would be desirable to set.

In step 240, in step 240, the tuner 130 selects a PWM signal output from the microcomputer 120, that is, a channel of a frequency band obtained by adding a frequency corresponding to a channel bandwidth to a reference channel frequency in step 230. The frequency of the tuned channel is output to the microcomputer 120.

In step 250, the microcomputer 120 determines whether the frequency of the channel tuned in step 240 is stored in the memory 160, and the frequency of the channel tuned in step 240 is stored in the memory 160. If not, the process returns to step 240 and the above processes are repeated. If the frequency of the channel selected in step 240 is stored in the memory 160, the process proceeds to step 260 and the channel tuned in step 240 is stored in memory ( It is determined whether or not the last channel of the channel stored in 160.

As a result, if the channel tuned in step 240 is not the last channel stored in the memory 160, the flow returns to step 230 to repeat the above-described steps, and the channel tuned in step 240 is stored in the memory 160. If the channel is the last channel, the flow proceeds to step 270 to determine whether the channel selected in step 240 is the reference channel selected in step 210.

If the channel tuned in step 240 is a reference channel tuned in step 210 as a result of the determination in step 270, all channels are tuned. Therefore, channel tuning is stopped, and the channel tuned in step 240 is tuned in step 210. If it is not one reference channel, the frequency of the channel having the smallest frequency among the channels stored in the memory 160 is output to the microcomputer 120, and then the process returns to step 230 and the above processes are repeated.

As described above, the channel tuning method according to the present invention has the effect of reducing the time required for channel tuning by omitting the search for a range in which no actual channel exists during VS channel tuning.

While the invention has been shown and described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various modifications, changes and omissions can be made without departing from the spirit and scope of the invention.

Claims (1)

In the VS tuning method of tuning a channel by outputting a pulse width modulated signal (PWM), A first step of tuning the reference channel; A second step of determining whether the reference channel selected in the first step corresponds to one of predetermined preset channels; A third step of outputting a PWM signal obtained by adding a predetermined frequency band to the frequency of the tuned reference channel if there is no designated channel matching as a result of the determination of the second step, and if the designated channel exists; ; A fourth step of sequentially tuning the next channel by sequentially increasing the frequency of the PWM signal of the third step by one step; A fifth step of determining whether the channel selected in the fourth step corresponds to one of preset channels; A sixth step of returning to the fourth step and repeating the step if there is no designated channel that matches the determination result of the fifth step, and determining whether the tuned channel is the last channel among the designated channels if the designated channel exists; A seventh step of returning to the fourth step if the final channel is not the same as the determination result of the sixth step, and repeating the step, and determining whether the tuned channel is the first reference channel if not the last channel; If it is determined that the seventh step is not the first reference channel, after outputting the PWM frequency corresponding to the first channel among the designated channels, the method returns to the fourth step and repeats the above step. Channel tuning method consisting of eight steps