1. Field of the Invention
The present invention relates to a channel selection device of a television, and in particular to an automatic channel memory and selection method of a television, capable of simply selecting a channel regardless of a cablecast or a wireless broadcast.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating a general TV set, comprising a tuner 1 for converting a wireless broadcast signal RF or a cablecast signal CATV to an intermediate frequency signal, a sound signal processing unit 2 for restoring a sound intermediate frequency signal SIF to a sound signal and outputting the sound signal to a speaker SP, a video signal processing unit 3 for separating a video intermediate frequency signal VIF into a luminance signal Y and a chrominance signal C, a RGB matrix 4 for restoring the luminance signal Y and the chrominance signal C outputted from the video signal process unit 3 into a primary color signals R, G, B and, thus, outputting the primary color signals R, G, B to a color picture tube CPT, and a microcomputer 5 for performing a control operation in accordance with various control command signals inputted from a remote control unit 6.
With reference to FIGS. 1 to 3, the operation of the above described TV set will now be described.
FIGS. 2A and 2B depict a flow chart illustrating an automatic channel selection procedure and a channel selection procedure.
FIG. 3 is a table comparing a wireless broadcast signal and a cablecast signal according to each frequency and each channel, wherein CH1 and CH70 to CH125 are the exclusive cablecast channels, CH2 to CH13 are the channels in which the wireless broadcast and the channels in which the wireless broadcast and the cablecast have identical channel numbers, but separate frequencies.
First, as shown in step 10 in FIG. 2, when a TV viewer selects a wireless broadcast or a cablecast by using a broadcast mode selection key Air/CATV equipped in the remote control unit 6, the microcomputer 5 checks whether a signal from an automatic channel set-up key is inputted or not.
Here, as shown in steps 16 to 20 in FIG. 2, the broadcast mode selection key Air/CATV is a toggle key, so when the microcomputer 5 receives a signal from the broadcast mode selection key Air/CATV, in a case where the present mode is the wireless broadcast mode, the 10 microcomputer 5 switches the wireless broadcast mode to a cablecast mode, and conversely, in case the present mode is the cablecast mode, the microcomputer 5 switches the cablecast mode to the wireless broadcast mode.
And, as shown in steps 11 and 12 in FIG. 2, when the microcomputer 5 receives a signal from the automatic channel set-up key, the microcomputer 5 distinguishes the present broadcast mode. Here, if the distinguished mode is the wireless broadcast mode, the microcomputer 5 outputs tuning data corresponding to the wireless broadcast to the tuner 1, for thereby sequentially selecting wireless broadcast channels CH2 to CH69 and memorizing channels having wireless broadcast signals.
On the other hand, as shown in step 13 in FIG. 2, if the distinguished mode is the cablecast mode, the microcomputer 5 outputs tuning data corresponding to the cablecast to the tuner 1, for thereby sequentially selecting cablecast channels CH1 to CH125 and finally completing the automatic channel set-up operation by memorizing channels having cablecast signals. As shown in steps 14 and 15 in FIG. 2, after the automatic channel set-up operation, when the microcomputer 5 receives a signal from a channel increase/decrease key operated by the TV viewer, the microcomputer 5 sequentially outputs tuning data of a cablecast channel or a wireless broadcast channel from the present broadcast mode, in accordance with the previously completed automatic channel set-up.
Accordingly, the tuner 1 converts the wireless broadcast signal or the cablecast signal to an intermediate frequency signal in accordance with the tuning data and the sound signal processing unit 2 restores the sound intermediate frequency signal SIF outputted from the tuner 1 to the sound signal SP, for thereby outputting the sound signal to the speaker SP.
And, the video signal processing unit 3 separates the video intermediate frequency signal VIF into the luminance signal Y and the chrominance signal C and the RGB matrix 4 restores the luminance signal Y and the chrominance signal C to the primary color signals R, G, B and thus outputs the primary color signals R, G, B to the color picture tube CPT, whereby the wireless broadcast or the cablecast is displayed on a screen.
Therefore, the TV viewer is able to simply select a desired channel without inputting the desired channel numbers one by one.
Also, when the viewer directly inputs a desired channel number, the microcomputer 5 recognizes a channel input and outputs tuning data, corresponding to the desired channel number inputted by the viewer, to the tuner 1, for thereby selecting the desired channel.
However, according to the conventional channel selection method, for the viewer to have the television memorize all the channels with respect to wireless broadcasts and cablecasts by selecting a wireless broadcast mode or a cablecast mode by using the broadcast mode selection key Air/CATV and then pressing the automatic channel set-up key on the selected mode, this requires two steps.
And, although the channels having broadcast signals are memorized through the automatic channel set-up procedure, when the viewer wants to select a certain channel, the viewer has to select the wireless broadcast mode or the cablecast mode and again press the channel increase/decrease key, thereby causing the viewer inconvenience to perform multiple operation.
Accordingly, it is an object of the present invention to provide an automatic channel memory and selection method for a TV set capable of memorizing each channel having a broadcast signal in a single step upon inputting an automatic setup key, regardless of a wireless broadcast mode or a cablecast mode being selected.
It is another object of the present invention to provide an automatic channel memory and selection method for a TV set to sequentially increase or decrease a memorized channel number, whenever a signal from a channel increase/decrease key is inputted, regardless of a wireless broadcast channel or a cablecast channel being selected.
It is still another object of the present invention to provide an automatic channel memory and selection method for a TV set to judge, in a case where a viewer directly inputs a desired channel number by using a number key, whether the inputted channel number corresponds to a wireless broadcast channel or a cablecast channel and to then output corresponding tuning data.
To achieve the above objects, there is provided a method which includes a step for checking an input from an automatic channel set-up key; a step for sequentially selecting wireless broadcast channels for thereby memorizing channels having a wireless broadcast signal when the automatic channel set-up key is inputted; a step for sequentially selecting cablecast channels for thereby memorizing channels having a cablecast signal; a step for checking an input from a channel increase/decrease key; and a step, in a case where the channel increase/decrease key is inputted, for selecting a desired channel by increasing or decreasing by single channels from the present channel, regardless of whether the present channel is a wireless broadcast channel or a cablecast channel.
To achieve the above objects, there is also provided a method which includes a step for checking an input from the number key; a step for checking whether a channel number inputted by a number key belongs to a first range, a second range, or a third range; a step, when the inputted channel number belongs to the first range, for outputting tuning data of a corresponding channel and thereby selecting a channel; a step for outputting tuning data of a wireless broadcast in the case where the inputted channel number belongs to the second range and for recognizing the present channel as a wireless broadcast channel and thereby selecting the channel in the case where a broadcast signal is detected in the corresponding channel; a step for outputting tuning data of a cablecast channel when the broadcast signal is not detected in the above step and for recognizing the present channel as a cablecast channel and thereby selecting the channel; and a step for outputting only a tuning data of a cablecast channel and thereby selecting the channel when the inputted channel number belongs to the third range.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.