KR0141860B1 - Method for preventing channel overlap on auto freguency tunning - Google Patents

Abstract

The present invention relates to a method for preventing channel duplication during automatic channel tuning. To this end, the same carrier signal is duplicated and tuned by using an automatic gain adjustment signal for maintaining a constant intensity of a video signal received during automatic channel tuning. A method for preventing the interference, the method comprising: comparing each channel tuned to each other when the automatic channel selection is terminated and checking whether there is a channel having the same local oscillation frequency; Comparing the strengths of the automatic gain adjustment signals of the two channels if there is a channel having the same local oscillation frequency in the checking process; Displaying a channel with a large intensity of the automatic gain adjustment signal and a small channel in the comparison process, and displaying a channel and a channel band when the strength of the automatic gain adjustment signal is the same; The channel duplication prevention method for automatic channel selection, which includes the step of deleting the channel selected by the user among the tuned channels and repeating the channel comparison process until the channel comparison is completed, prevents channel duplication.

Description

How to prevent channel duplication during channel auto tuning

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

2 is a flowchart illustrating a process of preventing channel duplication in automatic channel tuning according to a preferred embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: key input unit 20: microcomputer

30: tuner portion 40: image processing portion

50: OSD section 60: Synchronous separation section

70: AGC section 80: storage section

The present invention relates to a method for automatic channel tuning of a video device, and more particularly, to a method for preventing channel duplication during automatic channel tuning, in which a channel having the highest sensitivity is selected and tuned when the same broadcast is repeatedly tuned to multiple channels. will be.

In general, automatic channel tuning of a video device sequentially detects a VHF (Very High Frequency) low band to a UHF (Ultra High Frequency) band and recognizes a channel to which a synchronization signal is input as a broadcast signal. By saving only the channel that exists, it is a function that provides the user with convenience when switching channels.

However, in the conventional automatic channel tuning function, the low frequency band of the converted band is tuned to overlap with the high frequency band of the pre-converting band during the band conversion during the automatic tuning while converting the bands (VHF LOW, VHF HIGH, UHF). In other words, the same broadcast signal is duplicated and tuned to several channels, and the user has to check and watch the screen corresponding to the channel one by one, and there is an inconvenience of deleting a channel having poor reception sensitivity among the duplicated channels.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, so that the user can select a channel having the best reception sensitivity by displaying the duplicated channel when the same broadcast is tuned in duplicate. The purpose of the present invention is to provide a channel overlap prevention method for automatic channel tuning.

In order to achieve the above object, the present invention provides a method for preventing duplication of the same broadcast signal by using an automatic gain adjustment signal for maintaining a constant intensity of a video signal received during automatic channel tuning. Checking if there is a channel having the same local oscillation frequency by comparing the tuned channels with each other when tuning is completed; Comparing the strengths of the auto gain adjustment signals of the two channels if there is a channel having the same local oscillation frequency in the checking process; Displaying a channel with a large intensity of the automatic gain adjustment signal and a small channel in the comparison process, and displaying a channel and a channel band when the strength of the automatic gain adjustment signal is the same; The method provides a method for preventing channel duplication during automatic channel selection, including the step of deleting the channel selected by the user among the tuned channels and repeating the channel comparison process until the channel comparison is completed.

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

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

1 is a block diagram of a channel automatic tuning apparatus employed in accordance with the present invention. As shown in the figure, the channel automatic tuning apparatus employed in accordance with the present invention includes a key input unit 10, a microcomputer 20, a tuner unit 30, an image processing unit 40, an OSD unit 50, and synchronization separation. The unit 60 includes an AGC unit 70 and a storage unit 80.

In the figure, the key input unit 10 outputs an input signal resulting from the user's key operation in order to perform a desired operation of the video device.

In addition, the microcomputer 20 controls the overall operation of the imaging apparatus, outputs a tuning signal for tuning a channel corresponding to the input signal from the key input unit 10, and a recording signal for storing the channel when the synchronization signal is input. Outputs

In addition, the microcomputer 20 further includes a read signal for reading each channel information, a character control signal for displaying a channel comparison result, and a user's selection in order to compare channel information of each channel selected and stored as described below. A control signal for erasing the selected channel is output.

On the other hand, the tuner 30 outputs a broadcast signal tuned and received based on the tuning signal from the microcomputer 20, the automatic gain adjustment signal, and the fine adjustment signal (not shown), and the local oscillation frequency for overlapping channel comparison. Outputs

On the other hand, the local oscillation frequency is a fine signal not shown and the tuning signal from the microcomputer 20 to convert the broadcast signal induced by the antenna at the time of channel tuning into the desired IF (Intermediate Frequency, typically 45.75 MHz) video signal. Oscillated by fine adjustment signal for adjustment.

In addition, the image processing unit 40 processes and outputs an image signal input from the tuner unit 30 as a displayable signal, and the OSD unit 50 responds to the character control signal from the microcomputer 20 for text processing on the screen. On the basis of this, a text signal is generated and mixed with the video signal from the image processor 40 to be output.

In addition, the sync separator 60 separates the sync signal from the video signal from the video processor 40 and outputs the sync signal to the microcomputer 20.

On the other hand, the AGC unit 70 is proportional to the intensity of the input video signal to automatically adjust the gain so that the output of the video signal is always constant even when the size of the broadcast signal induced by the antenna of the tutor unit 30 changes. The automatic gain control signal (Automatic Gain Control) is applied to the tutor unit 30 to reduce the amplification degree when the intensity of the image signal is large, and to increase the amplification degree when the intensity of the image signal is small so that the image signal having a constant intensity is output. do. In addition, when the channels overlap, the automatic gain adjustment signal is output to the microcomputer 20 to compare the sensitivity of the received video signal.

The storage unit 80 then writes, reads, and deletes the selected channel information based on the write signal, read signal, and control signal from the microcomputer 20.

Next, a channel overlap prevention process in automatic channel tuning according to the present invention in the automatic channel tuning apparatus including the above-described configuration unit will be described in detail with reference to the flowcharts of FIGS. 1 and 2.

First, referring to the automatic channel tuning process, when the input signal for automatic channel tuning is output from the key input unit 10 by the user's key operation and is input to the microcomputer 20, the microcomputer 20 corresponds to a tuning signal corresponding to a low frequency. Is generated and applied to the tuner unit 30, and the tuner unit 30 applies the broadcast signal tuned and received by the tune signal to the image processor 40.

Meanwhile, in order to maintain the intensity of the input video signal, an automatic gain adjustment signal is generated by the AGC unit 70, fed back to the tutor unit 30, and also applied to the microcomputer 20.

Next, when the synchronization signal is separated from the video signal by the synchronization separating unit 60 and applied to the microcomputer 20, the microcomputer 20 determines the presence or absence of a broadcast signal based on the input synchronization signal (step 200).

Therefore, if there is an input of the synchronization signal, the microcomputer 20 stores the channel information (e.g., channel, local oscillation frequency signal, automatic gain adjustment signal) in the storage unit 80 (step 202).

Next, when automatic channel selection is completed by the above process (step 204), a process of selecting a duplicate channel, which is the main process of the present invention, is performed.

First, in order to sequentially compare each channel information tuned by the above-described process and stored in the storage unit 80, the two channels are read and the mutual local oscillation frequency signals are compared (step 206).

At this time, if the local oscillation frequency signal is the same, the two channel broadcast signals are regarded as the same broadcast signal and the strength of the automatic gain adjustment signal of the two channels with the same local oscillation frequency signal is selected to select a channel having good reception sensitivity among the overlapped two channels. Are compared (step 208).

Next, in the comparison of the automatic gain adjustment signals of the two channels (step 208), the channel having the smallest automatic gain adjustment signal is amplified by the tuner unit 30 because the automatic gain adjustment signal has a higher amplification than the channel having the larger gain. Due to the noise generated, the reception sensitivity is worse.

Therefore, in order to prevent channel duplication, a character control signal is generated to the OSD unit 50 to display a channel to be deleted among the two overlapped channels, that is, a channel having a small automatic gain adjustment signal in step 208, and then to the user. Cause it to be deleted (step 210).

On the other hand, if the strengths of the automatic gain adjustment signals of the two channels are the same in step 208 and 214, the number and channel bands (VHF LOW, VHF HIGH, UHF) of the two channels are displayed through the OSD screen (step 216). Allows the user to select which of two channels to delete.

Next, when the information of the two overlapping channels is displayed by the above (steps 212 and 216), the user checks whether the input signal for deletion is detected for a set time using the corresponding key of the key input unit 10 (step 212 If input, the corresponding channel information is controlled and deleted by controlling the storage unit 80 (step 218), and it is determined whether the channel comparison is completed (step 220), and if not, the next channel comparison is performed (step 206). When the channel comparison is complete, the routine ends.

Meanwhile, in the preferred embodiment of the present invention, although the user deletes the duplicated channel through the displayed OSD screen by the corresponding key operation, in order to provide more convenience, the reception sensitivity is reduced among the duplicated channel (determined in step 208). In this case, the modification may be performed in such a manner as to automatically delete a channel having different channels and channel bands (identified in step 214).

As described above, according to the present invention, the same channel is prevented from being duplicated and tuned to different channels, thereby avoiding the troublesome work of deleting unnecessary channels while the user checks all the tuned channels. In this case, the channel having a good reception state is discriminated by the microcomputer, not the audiovisual of the user, thereby more accurately selecting the channel.

Claims (1)

A method for preventing duplication of the same broadcast signal by using an automatic gain adjustment signal for maintaining a constant intensity of a video signal received during automatic channel tuning.At the end of automatic channel tuning, the channels tuned to each other are compared with each other. Checking whether there are channels having the same local oscillation frequency; Comparing the strengths of the automatic gain adjustment signals of the two channels if there is a channel having the same local oscillation frequency in the checking process; Displaying a channel with a large intensity of the automatic gain adjustment signal and a small channel in the comparison process, and displaying a channel and a channel band when the strength of the automatic gain adjustment signal is the same; And erasing the channel selected by the user from the tuned channels and repeating the channel comparison process until the channel comparison is completed.