KR19990049854A - Broadcast Signal Auto Tuning Method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcast signal tuning method, and more particularly, to a broadcast signal automatic tuning method for tuning in a frequency synthesis scheme. The present invention outputs the initial tuning frequency value to the tuner, and constantly increases the tuning frequency from the initial tuning frequency value to the first frequency interval to detect the reception section of the broadcast signal, and differs from the first frequency interval in the broadcast signal reception section. If the corresponding receiving point of the broadcast signal is detected by constantly decreasing / increasing the tuning frequency at the second and third frequency intervals, then determining whether the received signal is synchronized or not, and if the received signal has a synchronization signal, the current reception signal is received. It automatically tunes the broadcasting signal by memorizing the channel corresponding to the point. According to the present invention, channel tuning is performed using the frequency synthesis method as described above, so that broadcasts of neighboring countries having different broadcasting frequencies can be received.

Description

Broadcast Signal Auto Tuning Method

The present invention relates to a broadcast signal tuning method, and more particularly, to a broadcast signal automatic tuning method for automatically tuning a broadcast channel using a frequency synthesis method.

As a typical broadcasting signal automatic tuning method, the broadcasting signal was searched by increasing the frequency data of each broadcasting channel from the lowest channel to the highest channel at a constant channel frequency bandwidth. That is, for example, the VHF bandwidth is increased by 7 MHz, the UHF is increased by 8 MHz, and the channel corresponding to the received frequency is searched for, and the received channel is stored. In order to compensate for the received movement amount of the broadcast signal, the AFT was performed by adjusting the AFT (Auto Fine Tuning) range value for each manufacturer such as ± 3 MHz or ± 4 MHz.

However, in the conventional frequency synthesis tuning method, since the channel frequency is different for each country, a program suitable for the channel characteristics of each country is required, and there is a problem that broadcasting channels of various countries having various channel frequencies may be omitted.

Accordingly, an object of the present invention is to solve the above problems. During the initial channel search, a search is performed using a large search frequency band, and the broadcast signal reception section is found. The present invention provides an automatic tuning method for a broadcast signal to find an accurate broadcast receiving point.

1 is a view showing a broadcast signal tuning apparatus applied to the present invention,

2 is a view for explaining a broadcast signal automatic tuning method according to an embodiment of the present invention.

※ Explanation of codes for main parts of drawing

11: key input unit 12: tuner

13 memory 14 control unit

15: AFT circuit 16: display unit

A feature of the present invention for achieving the above object is a tuning preparation step of outputting an initial tuning frequency value to the tuner in a method for detecting a broadcast channel using a tuner of the frequency synthesis method, starting from the initial tuning frequency value A broadcast signal receiving section detecting step of detecting a reception section of a broadcast signal by constantly increasing the tuning frequency at one frequency interval, and constantly tuning the second and third frequency intervals different from the first frequency interval in the broadcast signal reception section. A broadcast signal reception point detecting step of detecting a corresponding reception point of a broadcast signal by decreasing / increasing a frequency, a synchronization signal judging step of determining whether or not a signal received at the detected reception point is synchronized, and a synchronization signal is applied to the received signal. If present, there is provided a method for auto-tuning a broadcast signal comprising a channel memory step for memorizing a channel corresponding to a current reception point. All.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an apparatus applied to a broadcasting signal automatic tuning method of the present invention. The apparatus of FIG. 1 has a key input section 11. The key input section 11 inputs an automatic program tuning key signal for automatically tuning the broadcast channel at the beginning of setup. The control unit 14 outputs a tuning frequency signal corresponding to the automatic program tuning key signal applied from the key input unit 11 to the tuner 12. The control unit 14 stores and stores the initial tuning frequency value at the time of the initial setup, and outputs to the tuner 12 the UP / DOWN constant tuning frequency from the initial tuning frequency value. At this time, the AFT (Automatic Fine Tuning) circuit 15 is set to a high (H) state in the initial no signal state, and when a broadcast signal is detected by the tuner 12, the AFT (Automatic Fine Tuning) circuit 15 switches to a low (L) state. The controller 14 determines whether the broadcast channel is tuned according to the state (H or L) of the AFT signal applied from the AFT circuit 15. The controller 14 receives the "L" signal from the AFT circuit 15, that is, when the broadcast channel is tuned, stores the tuned channel in the memory 13, and displays the broadcast signal for the broadcast channel at this time. Let's show it for a while in 16).

2 is a flowchart illustrating a broadcast signal automatic search method of the present invention.

The user inputs an automatic program tuning key signal for receiving a broadcast signal through the key input unit 11. The control unit 14 outputs an initial tuning frequency value for receiving the broadcast channel to the tuner 12 according to the automatic program tuning key signal (step 210). Here, the initial tuning frequency value refers to the lowest frequency value. Then, the controller 14 increases the tuning frequency by 500 Hz from the initial tuning frequency value (step 215), and checks whether the AFT signal output from the AFT circuit 15 is high (H) or low (L). Step 220). Here, the AFT circuit 15 is configured to output a high (H) signal in a no signal section in which no channel is received and a low (L) signal in a section in which a broadcast signal is received. In step 220, if the AFT signal is "H", the flow returns to step 215 to repeat the step. In other words, the tuning frequency is continuously increased by 500 kHz until the receiving section of the broadcast signal is detected, that is, until the AFT signal becomes "L". When the controller 14 receives the "L" signal from the AFT circuit 15, the controller 14 decreases the tuning frequency by 150 kHz and outputs it to the tuner 12 (step 225), and checks the AFT signal again (step 230). step). If the AFT signal is "L", it is determined whether the number of times the tuning frequency is reduced by 150 Hz is greater than or equal to the preset number (step 240). If the number of times by which the tuning frequency is decreased by 150 Hz is more than the preset number, the flow proceeds to step 255, which will be described later. However, if the number of times by which the tuning frequency is decreased by 150 Hz is not more than the preset number, the process returns to step 225 and repeats the steps. In step 230, if the AFT signal is "H", the controller 14 increases the tuning frequency by 50 Hz and outputs the tuner 12 to the tuner 12 (step 235). Then, the AFT signal is checked (step 245). If the AFT signal is "H", it is determined whether the number of times in which the tuning frequency is increased by 50 Hz is greater than or equal to the preset number (step 250). If the number of times by which the tuning frequency is increased by 50 Hz is more than the preset number, the flow proceeds to step 255. However, if the AFT signal is "L", it is determined whether the synchronous detection is performed in step 255. That is, the presence or absence of a synchronization signal is detected to determine whether there is a broadcast signal received at the current tuning frequency point. If the synchronization is detected, the control unit 14 stores the channel of the broadcast signal received at the currently set tuning frequency point in the memory 13, and controls the display unit 16 to show the broadcast signal for a while. However, if the synchronization is not detected, the process returns to step 215 and repeats the steps.

The present invention has the effect of receiving a broadcast of a neighboring country having a different broadcasting frequency by performing channel tuning by sequentially increasing or decreasing the tuning frequency from the lowest tuning frequency value at a constant tuning frequency interval.

Claims (4)

In the method for detecting a broadcast channel using a frequency synthesis tuner, A tuning preparation step of outputting an initial tuning frequency value to the tuner; A broadcast signal receiving section detecting step of detecting a receiving section of a broadcast signal by constantly raising a tuning frequency from the initial tuning frequency value to a first frequency interval; A broadcast signal receiving point detecting step of detecting a corresponding reception point of a broadcast signal by constantly decreasing / increasing a tuning frequency at second and third frequency intervals different from the first frequency interval in the broadcast signal receiving section; A synchronization signal determination step of determining whether the signals received at the detected reception points are synchronized; And And a channel memory step of storing a channel corresponding to a current reception point when a synchronization signal is present in the received signal. The method of claim 1, wherein the presence or absence of the broadcast signal is determined based on a change in the state (H or L) of the AFT signal. The method of claim 1, wherein the first frequency interval is larger than the second frequency interval by a predetermined size, and the second frequency interval is larger than the third frequency interval. The method of claim 1, wherein if there is no synchronization signal received, the next broadcasting signal receiving section is detected by increasing a tuning frequency at the first frequency interval at a current detected point.