KR19990051264A - How to automatically select a broadcast channel for a video cassette recorder - Google Patents

Abstract

The present invention relates to an apparatus for receiving an image signal, and by the channel automatic tuning mode, the microcomputer 12 detects and stores only a broadcast channel among all receivable channels of the tuner 11, and the image quality of a predetermined step by a user. If this is selected, only the broadcast channel whose automatic gain control voltage above the automatic gain control voltage which can satisfy the selected picture quality of the broadcast channels is continuously detected for a predetermined time is redetected and erased from the broadcast channel.

That is, according to the present invention, only the broadcast channel that satisfies the image quality selected by the user is reset as the broadcast channel.

Description

How to automatically select a broadcast channel for a video cassette recorder

The present invention relates to a video cassette recorder, and more particularly, to a method of automatically tuning a broadcast channel of a broadcast station and selecting and storing only a broadcast channel having a predetermined image quality among the tuned broadcast channels.

A typical video cassette recorder is provided with a tuner, which is configured to receive general television broadcasts.

A television broadcast is a broadcast signal (video and audio signal) produced by a broadcast station for general public, and these broadcast signals are modulated and transmitted to a channel or frequency band assigned to each broadcast station.

Accordingly, viewers of a video cassette recorder must tune the tuner's receive channel to one of the broadcast stations' broadcast channels in order to receive and view the broadcast signal. That is, the viewers can select and receive one of the broadcast channels by controlling the tuner to adjust its reception frequency band. Here, as described above, broadcast stations are allocated to the broadcast stations, and thus, broadcast signals are not transmitted to all channels that can be received by the tuner. Accordingly, there may occur a case where a broadcast signal is received when the user changes its reception channel (this channel may be a channel that is allowed to broadcast to a broadcast station) while a broadcast signal is not received.

In order to alleviate this inconvenience, conventionally, a broadcast channel automatic search and storage function is added to a video cassette recorder. That is, the conventional video cassette recorder automatically changes the reception channel from the lowest receivable channel to the highest channel of the tuner when the broadcast channel automatic search and storage mode is set, and automatically searches only the channel through which the broadcast signal is received. In other words, only the channel on which the broadcast is being performed is automatically stored. When the user drives the channel up / down key, the user can turn on / down the channel only for the stored channel, that is, the channel on which the broadcast is being performed, and receive the signal of the corresponding channel. As a result, only the channel on which the broadcast is performed is always available for viewing.

On the other hand, in the conventional video cassette recorder, the determination of whether or not broadcast is being performed on the reception channel generally uses a method using a synchronization signal. That is, since a broadcast signal should normally include a synchronization signal, it is determined whether the broadcast signal is a broadcast signal based on whether the received signal includes a synchronization signal, particularly a vertical synchronization signal.

However, there is a problem that the method of determining whether the broadcast signal using the synchronization signal is incorrect. That is, in the case of a broadcast signal, particularly a wireless broadcast signal, there is a lot of noise caused by an external environment. Thus, there is a problem that a channel which is in a weak electric field, that is, a channel that the user cannot view, is set as a broadcast channel.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object of the present invention is to broadcast a video cassette recorder, which enables a user to set a broadcast channel condition so that only a broadcast channel having a predetermined image quality can be reset as a broadcast channel. It is to provide a channel automatic selection method.

The present invention for achieving this object has a broadcast channel automatic tuning mode for tuning only the broadcast channel by the synchronization signal, outputs an automatic gain control voltage corresponding to the electric field level of the received broadcast channel, A video cassette recorder in which image quality levels are divided and stored according to a level, the method comprising: determining whether a broadcast channel automatic tuning mode is set; If a broadcast channel auto-tuning mode is set, storing only the channel where the synchronization signal is detected as a broadcast channel; Displaying a predetermined time that the broadcast channel automatic tuning mode is terminated and an image quality can be selected; If a predetermined picture quality is selected within the predetermined time, sequentially receiving broadcast signals of the stored broadcast channels; Canceling the received broadcast channel from the broadcast channel when the automatic gain control voltage equal to or greater than the automatic gain control voltage corresponding to the selected picture quality is continuously generated among the received broadcast channels.

1 is a block diagram of a video cassette recorder performing a method for automatically selecting a broadcast channel according to the present invention;

2 is a flowchart of a broadcast channel automatic selection method of a video cassette recorder according to the present invention;

<Description of the symbols for the main parts of the drawings>

11: tuner 12: micom

13 synchronization detection unit 14 recording processing system

15 deck 16: regeneration treatment system

17: OSD unit 18: modulator

19: key metrics

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

1 is a block diagram of a video cassette recorder for performing an inter-channel interference prevention method according to the present invention, including a tuner 11, the tuner 11 of the channel corresponding to the tuning signal of the microcomputer 12; It is configured to receive a signal and apply it to the synchronization detection unit 13 and the recording processing system 14.

At this time, the tuner 11 is usually equipped with a built-in automatic gain control device, the automatic gain control device is a device for maintaining a constant in the electric field strength of the signal received from the tuner 11, the automatic gain control device is internal A method of generating an automatic gain control voltage inversely proportional to the electric field of the received signal of the tuner 11 and controlling the gain of the output signal of the tuner 11 using this automatic gain control voltage is adopted. Since the automatic gain control device in the tuner 11 is an easy technique for those skilled in the art of the present invention, illustration and detailed description are omitted herein.

On the other hand, the tuner 11 of the present invention is configured to apply the automatic gain control voltage of the internal automatic gain control device to the microcomputer 12, and the microcomputer 12 uses the automatic gain control voltage to carry out the present invention. Consists of.

The synchronization detector 13 detects a synchronization signal, that is, horizontal and vertical synchronization signals, from the signal of the tuner 11 and applies it to the microcomputer 12.

On the other hand, the recording processing system 14 is configured to record the received broadcast signal of the tuner 11 and apply it to the deck 15 according to the recording control signal of the microcomputer 12, and the deck 15 has a microcomputer 12 Drive in the drive mode according to the control of That is, the deck 15 drives in the recording mode when the recording control signal is applied from the microcomputer 12 to record the broadcast signal of the recording processing system 14 on the magnetic tape, and when the reproduction control signal is applied from the microcomputer 12 It is configured to drive in the reproduction mode to read out the broadcast signal recorded on the magnetic tape and apply it to the reproduction processing system 16.

In addition, the deck 15 of the present invention can be driven in various modes such as a fast play mode and a pause mode according to the drive control signal from the microcomputer 2, but the drive mode of the deck and the drive thereof. The mechanism is a technical matter that can be easily understood by those skilled in the art of the present invention, the detailed description thereof is omitted.

The signal processed and output by the reproduction processing system 16 and the received image signal of the tuner 11 are applied to the OSD unit 17, and the OSD unit 17 corresponds to a predetermined OSD control signal of the microcomputer 12. And a text signal or a blue back signal are mixed with the video signals of the tuner 11 and the reproduction processing system 16 and output.

On the other hand, the OSD unit 17 is connected to the modulator 18, the modulator 18 modulates the output signal of the OSD unit 17 to a predetermined channel (3 or 4 channels) under the control of the microcomputer 12 Or output directly to an original state without modulating the input video signal.

Meanwhile, as shown, the key matrix 19 is connected to the microcomputer 12, and the function key (channel selection key (consisting of numeric keys), channel up / down key, power on / off key) of the key matrix 19 is connected. , A playback key, a modulator modulation channel selection key, and the like), and the microcomputer 12 performs the operation described below in accordance with the driving of these keys.

2 shows an operational flowchart of a microcomputer 12 for carrying out the present invention.

As shown in the figure, the microcomputer 12 determines whether the channel automatic tuning mode is set by pressing the channel automatic tuning key (S1). When the channel automatic tuning mode is set, the microcomputer 12 performs the same channel automatic tuning mode as in the prior art (S2). That is, the received channel of the tuner 11 is changed and received from the lowest channel to the highest channel of the tuner 11, and among the received signals, only the channel in which the synchronization signal is detected by the synchronization detector 13 is set as a broadcast channel. To save. Since this process is a conventional technology as described above, a detailed description thereof is omitted.

In step S2, the microcomputer 12 performs the channel auto tuning mode. Then, the microcomputer 12 proceeds to step S3. The OSD unit 17 terminates the channel auto tuning mode and selects the desired picture quality according to the set broadcast channel. OSD text signal is output.

The OSD text signal allows the user to select a picture quality using the keys of the key matrix 19. For example, one or three levels can be distinguished from each other by the degree of image quality. Herein, the microcomputer 12 of the present invention determines the video quality of the broadcast channel as follows.

That is, the automatic gain device is configured to output the automatic gain control voltage as described above corresponding to the electric field of the video signal received by the tuner 11. At this time, the automatic gain control voltage becomes inversely proportional to the electric field of the video signal, and the automatic gain control voltage will soon be said to represent the electric field level of the video signal received by the tuner 11. Here, when the electric field level of the video signal is high, the image quality will be clear, and when the electric field level of the video signal is low, the image quality will be deteriorated.

Here, when the image signal received by the tuner 11 has the sharpest state, the automatic gain control voltage of the tuner 11 is less than or equal to the first voltage, and the image quality of the tuner 11 is referred to as image quality 1, and the image quality is deteriorated. When the automatic gain control voltage at this time is equal to or less than the second voltage, the image quality at this time is referred to as image quality 2, the automatic gain control voltage at a state deteriorated than the image quality 2 as the third voltage, and the image quality at this time is referred to as image quality 3 At this time, in the microcomputer 11 of the present invention, these first to third voltages are stored therein.

In the present invention, as described below, the user can select the image quality 1-3 state. For example, the selection can be made by, for example, the numeric key of the key matrix 18, that is, the image quality 1 state as the numeric key 1, and the image quality 2 and 3 states. The numeric keys 2 and 3 were selected.

After performing step S2, the microcomputer 12 determines whether the key signal for selecting the image quality as described above, that is, the signal corresponding to the numeric keys 1-3, is applied from the key matrix 19 within the predetermined time (S2). S4, S5).

When the user selects one of the numeric keys 1, 2, and 3 by performing steps S4 and S5, the microcomputer 12 tunes the tuning signal corresponding to the lowest channel of the broadcast channel tuned in step S2. And the tuner 11 to receive the signal of the corresponding broadcast channel (S7.), The microcomputer 12 determines that the automatic gain control voltage applied from the tuner 11 corresponds to the image quality selected by the user. It is determined whether or not the voltage (any one of the first to third voltages) is lower (S8, if the voltage is higher than the step S10. If the voltage is higher than this, the tuner 11 deletes the current reception channel from the broadcasting channel. In other words, if the broadcast channel being received by the tuner 11 does not reach the quality set by the user, the tuner 11 cancels the stored broadcast channel.

In addition, the microcomputer 12 proceeds to step S10 and determines whether the channel being tuned by the tuner 11 corresponds to the highest channel among preset broadcast channels. Otherwise, the tuner 11 changes the reception channel of the tuner 11 to the next broadcast channel of the preset broadcast channel among the preset broadcast channels (S11, and then proceeds to step S8). It is determined whether a video signal satisfying the PMI is received and the unsatisfied broadcast channels are deleted from the broadcast channel.

Meanwhile, as a result of the determination of steps S4 and S5, when the numeric keys 1, 2 and 3 for selecting the image quality are not pressed, the microcomputer 12 outputs the OSD text signal output of the OSD unit 17 in step S6. You quit and end the whole process.

As can be seen from the above description, in the present invention, broadcast channels that receive a broadcast signal that does not satisfy the user-selected picture quality among the broadcast channels tuned by the channel tuning mode are automatically deleted so that the user has the selected picture quality. The effect is that only channels can be tuned.

Claims (1)

It has a broadcast channel automatic tuning mode for tuning only a broadcast channel by a synchronization signal, outputs an automatic gain control voltage corresponding to the electric field level of the received broadcast channel, and the image quality stages are classified according to the level of the automatic gain control voltage. A stored video cassette recorder, Determining whether the broadcast channel auto-tuning mode is set; If the broadcast channel automatic tuning mode is set, storing only a channel where the synchronization signal is detected as a broadcast channel; Displaying a predetermined time that the broadcast channel automatic tuning mode is terminated and an image quality can be selected; If a predetermined picture quality is selected within the predetermined time, sequentially receiving broadcast signals of the stored broadcast channels; If the automatic gain control voltage equal to or greater than the automatic gain control voltage corresponding to the selected picture quality is continuously generated from the received broadcast channels for a predetermined time, erasing the received broadcast channel from the broadcast channel. Way.