KR0126797B1 - Auto-selection method & apparatus of broadcasting formula - Google Patents

Abstract

An apparatus and a method for automatically selecting a broadcasting mode are disclosed. The method comprises a step of checking the existence of the video signal; a step of setting a second broadcasting mode by changing the channel; a step of setting a third broadcasting mode; and a step of setting a first broadcasting mode. Since, the broadcasting mode is automatically selected, a user cannot select a broadcasting mode.

Description

Broadcasting method automatic selection method and device

1 is a block diagram of a broadcast receiver according to the present invention.

2 is a flow chart of a preferred embodiment for explaining the broadcast method automatic selection method according to the present invention.

The present invention relates to a broadcast method automatic selection method and apparatus, and more particularly, to a broadcast method automatic selection method and apparatus that can automatically select a broadcast method in a television broadcast receiver such as a video tape player or a television receiver. will be.

The frequency of the fixed television signal is the standard frequency method (hereinafter referred to as STD method) used by a television broadcasting station, and the channels of 5 and 6 are 2 MHz higher than the frequency of the STD method and the same IRC (Increment Related Carrier) method and all channels in the remaining channels. There is a Harmonic Related Carrier (HRC) method that is 1.25 MHz lower than that of the STD method. Therefore, the wired television signal is transmitted by one of these three methods depending on the wired television company.

However, manufacturers and manufacturers who manufacture and sell television broadcast receivers such as VCRs and TVs must manufacture so that consumers can use the wired television system without limitation.

Therefore, in the related art, STD, HRC, and IRC mode selection switches are provided in the broadcast receiver so as to be used in accordance with the wired television system that a consumer wants to use. In the mode selection method, when tuning, the frequency data corresponding to the selected method is supplied to the tuner, and the frequency data is roughly tuned and the AFT is performed to perform fine tuning to receive a broadcast. Since this method selects a broadcasting method, a narrow AFT range is set to allow precise tuning in a short time. Therefore, since the AFT range is set narrowly, when the selection of the broadcasting method is incorrect in the AFT OFF state, reception may not be performed, and there is a hassle and inconvenience of confirming whether the broadcasting method is properly selected.

Another method is to set the wide AFT range without selecting the broadcasting method, and if the station is tuned, the frequency data is supplied to the tuner to perform the AFT, regardless of the method. There is no inconvenience to install and operate the selector switch according to the broadcasting method, but there is a problem that the AFT takes a long time of several seconds and the tuning may not be possible depending on the deviation of the AFT range.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus capable of automatically selecting a broadcast method in order to solve the above problems of the prior art.

In order to achieve the above object, the method of the present invention calculates the deviation between the frequency of the first broadcast method and the AFT frequency if there is a video signal received by performing AFT by tuning one channel and the calculated deviation is calculated as the first and the first. Selecting a second broadcast method when approaching a frequency deviation of the second broadcast method; Calculating a deviation between the frequency of the first broadcast method and the AFT frequency and receiving the video signal, and selecting the third broadcast method if the calculated deviation approaches the frequency deviations of the first, second, and broadcast methods; And selecting a first broadcast method when the received video signal is present and the frequency of the first broadcast method and the AFT frequency are close to each other.

The apparatus of the present invention is a broadcast receiving apparatus for receiving a wired television broadcast, which receives a television broadcast signal and outputs an image intermediate frequency signal of a channel selected among the television signals received according to an input tuning voltage, A tuner circuit section for generating a corresponding local oscillation frequency signal; A demodulation circuit unit for demodulating the video signal by inputting the video intermediate frequency signal and generating an AFT signal; A PLL circuit section for varying and outputting the tuning voltage in a direction of reducing a deviation between the local oscillation frequency and a frequency corresponding to input data; And sequentially increasing the channel data from the initial channel data and outputting the channel data to the PLL circuit unit, and in response to the input of the AFT signal of the channel tuned by the channel data, the AFT frequency corresponding to the AFT signal and the frequency deviation of the first broadcasting scheme. If the frequency deviation is close to the frequency deviations of the first and second broadcast methods, select the second broadcast method. If the frequency deviations are close to the frequency deviations of the first and third broadcast methods, select the third broadcast method. And a broadcasting method automatic selection circuit unit for selecting the first broadcasting method.

Hereinafter, with reference to the preferred embodiment of the present invention shown in the accompanying drawings will be described in detail the present invention.

In the broadcasting method automatic selection method of the present invention, selecting an initial channel and performing AFT to check the presence or absence of a received video signal, and if there is a received video signal, the AFT frequency is higher than the frequency of the first broadcasting method. Setting a second broadcast mode when the channel is checked at least one time by changing the channel at least once while changing the channel at least once, and the AFT frequency is not lower than the frequency of the first broadcast method by more than the first frequency deviation. Setting a third broadcast method if the AFT frequency in a specific channel is higher than the frequency of the first broadcast method by at least one or more times while changing the specific channel at least once, and checking at least one time; The AFT frequency is not lower than the first frequency deviation by more than the frequency of the first broadcasting method, and the AFT frequency in a specific channel is Checking whether the channel is not higher than the frequency of the first broadcast method by more than a second frequency deviation by changing the channel at least once and setting the first broadcast method when the channel is checked at least once.

The first broadcast method is a standard television broadcast method, the second broadcast method is an HRC method having a frequency 1.25MHz lower in all channels than the frequency of the first broadcast method, and the third broadcast method is 5 and 6 channels. Is an IRC scheme having a frequency of 2 MHz higher than that of the first broadcast scheme.

Setting the initial channel to two channels speeds up the time for determining the broadcast method. In other words, starting from channel 2, the HRC method is determined in 2-4 channels, the IRC method is determined in 5 and 6 channels, and the STD method is determined after 6 channels. It can be set to fit.

Here, the threshold value of the frequency deviation of the first and second broadcast methods is 1 MHz, and the threshold value of the frequency deviation of the first and third broadcast methods is -1.5 MHz.

1 is a block diagram of a broadcast receiving apparatus according to the present invention.

In FIG. 1, a television broadcast signal is received through an antenna or a cable, and an image intermediate frequency signal IF of a channel selected among the television signals received according to the input tuning voltage VT is output and corresponds to the channel selected. A tuner circuit unit 10 for generating a local oscillation frequency signal OSC, a demodulation circuit unit 20 for demodulating an image signal by inputting the image intermediate frequency signal IF, and generating an AFT signal, and the local oscillation frequency signal The PLL circuit unit 30 which outputs the tuning voltage VT by varying and outputting the tuning voltage VT in a direction in which the deviation between the OSC and the reference frequency selected by the input data PLL DATA is reduced, and channel data sequentially from the initial channel data. Increase to and output to the PLL circuit section 30, and control the TV signal and local oscillation frequency received in response to the AFT signal to be tuned and tuned by this channel data. In response to the input of the AFT signal, the AFT frequency corresponding to the AFT signal and the frequency deviation of the first broadcast method are obtained. If the frequency deviation is close to the frequency deviation of the first and second broadcast methods, the second broadcast method is selected. And a broadcast method automatic selection circuit unit 40 for selecting the third broadcast method when the frequency deviation between the first and third broadcast methods is close, and selecting the first broadcast method when it is near zero. Here, the first broadcast is an STD method used by a television station, the third broadcast method is 2 MHz higher than the frequency of the STD method in channels 5 and 6, and the same Increment Related Carrier (IRC) method in the remaining channels, and the second broadcast method. Is a Harmonic Related Carrier (HRC) that is 1.25MHz lower than the STD method over all channels. The broadcast type automatic selection circuit 40 is composed of a microprocessor.

Referring to the flowchart of Fig. 2 showing the automatic selection method of the embodiment used in the apparatus of the present invention configured as described above is as follows.

When the automatic selection routine of the system starts, first, the flag bits D1 and D2 are set to zero (step 102), and two channel data of the STD method are generated (step 104). Accordingly, the PLL circuit unit 30 generates a VT voltage to tune two channels, inputs an IF signal from the demodulation circuit unit, generates an AFT signal, inputs the AFT signal, and performs the AFT again through the PLL circuit unit 30 ( Step 106) The presence or absence of a video signal is checked (step 108). At this time, if tuning is not possible, since there is no video signal, channel data is increased by 1 (step 110) and step 106 is repeated to check the next channel. If there is a signal in step 108, the deviation (fd) of the frequency of the STD and the AFT frequency is calculated (step 112). If the deviation is greater than the first threshold value f1 (= 1 MHz), the flag is greater. The bit D1 is set to 1 (step 116) and the flag bits D1 and D2 are checked (step 118). If both are not 1, the step 110 is repeated. If both are set to 1 in step 118, the process ends with setting the HRC method (step 120). That is, when judging two channels continuously, if the frequency deviation is more than 1 MHz, it is recognized that the second broadcast signal is being received.

If it is small in step 114, it is checked whether 5 channels are currently designated (step 122). If it is 5 channels, it is checked whether the frequency deviation is smaller than the second threshold value f2 (= -1.5 MHz). The flag bit D1 is set to 1 (step 126), the flag bits D1 and D2 are checked (step 128), and if both are not 1, step 110 is repeated. In step 122, it is checked whether it is not 5 channels or 6 channels (step 132). If it is 6 channels, steps 124-128 are performed. If both are set to 1 in step 128, the IRC method is set (step 130). That is, when judging two channels continuously, if the frequency deviation is less than -1.5 MHz, it is recognized that the third broadcast signal is being received.

In step 132, if not 6 channels, the flag bit D1 is set to 1 (step 134) and the flag bits D1 and D2 are checked (step 136). If both are not 1, step 110 is repeated. If both are set to 1 in step 136, it is checked whether the channel is larger than 6 channels (step 138), or if the step 110 is repeated and large, the STD method is set (step 140). That is, when judging two channels continuously, if the frequency deviation is less than 1 MHz and greater than -1.5 MHz, the first broadcast signal is recognized.

As described above, in the present invention, since the broadcast receiver recognizes the broadcast method of the received broadcast signal and automatically selects and sets a mode according to the broadcast method, the user does not have to set the set according to the broadcast method. There is no fear of operation. In addition, since the AFT range need not be set wide, the tuning operation is quickened by several milliseconds and there is no need to provide a selection switch or the like.

Claims (5)

CLAIMS 1. A method of automatically selecting a broadcast method of a broadcast receiver for receiving cable television broadcasting, the method comprising: selecting an initial channel and performing an AFT to check whether there is a video signal received; If there is a video signal being received, checking whether the AFT frequency is lower than the frequency of the first broadcasting method by more than the first frequency deviation by changing the channel at least once, and setting the second broadcasting mode if it is checked at least once. ; The specific channel is changed at least once whether the AFT frequency is not lower than the frequency of the first broadcasting method by more than the first frequency deviation, and the AFT frequency in the specific channel is higher than the frequency of the first broadcasting method by more than the second frequency deviation. Setting a third broadcast method if checked while checking at least once; And whether the AFT frequency is not lower than the frequency of the first broadcasting scheme by more than the first frequency deviation, and the frequency AFT in a specific channel is not higher than the frequency of the first broadcasting scheme by more than the second frequency deviation by at least one channel. And setting a first broadcast method when the change is checked and checked at least once. The method of claim 1, wherein the first broadcast method is a standard television broadcast method, and the second broadcast method is an HRC method having a frequency lower by 1.2 MHz in all channels than the frequency of the first broadcast method, and the third broadcast method. Method is an automatic IRC method, characterized in that the IRC method having a frequency 2MHz higher than the first broadcast method in 5 and 6 channels. The method of claim 1, wherein the initial channel is two channels. If there is a video signal received by performing AFT by tuning one channel, a deviation between the frequency of the first broadcasting method and the AFT frequency is calculated, and if the calculated deviation is close to the frequency deviation of the first and second broadcasting methods, the second signal is calculated. Selecting a broadcasting method; Calculating a deviation between the frequency of the first broadcast method and the AFT frequency and receiving the video signal, and selecting the third broadcast method when the calculated deviation approaches the frequency deviation of the first and third broadcast methods; And selecting a first broadcast method when there is a video signal received and a frequency of the first broadcast method and an AFT frequency are close to each other. A broadcast receiving apparatus for receiving a cable television broadcast, comprising: receiving a television broadcast signal and outputting an image intermediate frequency signal of a channel selected among the television signals received according to an input tuning voltage and a local oscillation frequency signal corresponding to the channel selected; A tuner circuit unit generating a; A demodulation circuit unit for demodulating the video signal by inputting the video intermediate frequency signal and generating an AFT signal; A PLL circuit section for varying and outputting the tuning voltage in a direction of reducing a deviation between the local oscillation frequency and a frequency corresponding to input data; And sequentially increasing the channel data from the initial channel data, outputting the channel data to the PLL circuit, and responsive to the input of the AFT signal of the channel tuned by the channel data. If the frequency deviation is close to the frequency deviations of the first and second broadcast methods, select the second broadcast method. If the frequency deviations are close to the frequency deviations of the first and third broadcast methods, select the third broadcast method. And a broadcast method automatic selection circuit for selecting the first broadcast method.