KR20000013991A - Apparatus and method for automatically selecting a channel of an analog/digital tv - Google Patents

Abstract

PURPOSE: A method is provided to enable an automatic channel selection rapidly and easily. CONSTITUTION: In the analog/digital TV having a micom, an analog tuner and a digital tuner, first of all, when a user selects an automatic channel select mode (S31), select data for all broadcasting channels are sequentially outputted from the micom to the analog and digital tuners. After receiving a signal corresponding to an outputted select data from the micom to the analog and digital tuners, whether an analog broadcasting signal exists at a present channel (S36) or whether a digital broadcasting signal exists at the present channel (S33) is checked through a set of signal processes. And, a corresponding program information is stored after recording an analog broadcasting signal or a digital broadcasting signal to corresponding channels according to the check result (S34, S37, S35).

Description

Automatic channel tuning device and method of analog / digital TV

TECHNICAL FIELD The present invention relates to TVs, and more particularly, to an automatic channel tuning apparatus and method for analog / digital TVs.

Analog TVs are being introduced to consumers in various forms, starting with small models such as 14 inches, and projection TVs over 60 inches.

However, the current analog TV shows various problems as it becomes larger and more functionalized. First, in view of image quality, the quality of video quality is degraded when watching the current TV broadcasting quality such as NTSC, PAL or SECAM on a large TV. You can experience it.

Second, in view of the limit of broadcasting channels that can be serviced in the future, the number of currently allocated TV broadcasts is limited to about 80 in total in both microwave and microwave channel bands. It is only about.

Third, the limitation as a unidirectional medium is mentioned.

That is, TV until now has only a function as a reception medium, but as the demand for interactive functions explodes due to the appearance of personal computers and the Internet, future TVs are required to function as interactive terminals.

Finally, the saturation of the analog TV market.

In other words, Korea currently has more than 2 units of supply per household, so we cannot expect any more demand.

As a result, digital TVs have emerged as a solution to the problems of the analog TV market. Digital TVs have dramatically improved the video quality of analog TVs to provide more than twice as vivid image quality as analog TVs, and interference between adjacent channels Since there is no channel area, it is possible to use all channel areas that were not used previously.

In addition, according to the Program Service Information Protocol (PSIP), a broadcasting supplementary information standard that provides detailed information about broadcast programs in the US Digital TV Standard Advanced Television Service Committe (ATSC) proposed in November 1997, One high-resolution (HD) digital broadcast program or four standard-definition (SD) digital broadcast programs can be transmitted per channel, that is, a 6 MHz band, which can provide hundreds of diverse services. By providing services such as Internet service, home shopping, and home banking, it is highly likely that analog channels will be replaced by digital channels in the near future, and explosive demand window is expected in the future.

At this time, the PSIP standard is described in more detail. Major channel numbers and minor channel numbers have been enacted for channel allocation. The major channel numbers are allocated to the 6 MHz band used for terrestrial broadcasting. The channel number represents a channel number, and the minor channel number represents a channel number allocated to a digital service channel transmitted through a 6 MHz band.

However, ATSC assigns a specific value to each broadcaster for major channels, whereas minor channel assignments can be changed from time to time by managing broadcaster for minor channel assignments. Therefore, TVCT (Terrestrial Virtual Channel) is a digital channel information table provided by PSIP. Table) can be used to grasp major channel and minor channel information of a plurality of digital channels.

Major number Minor number Short name Carrier frequency (MHz) Channel TS ID Program number flag Service type Source ID Explanation 12 0 NBZ 205.25 0X0AAO 0X0AA0 Analog 20 Channel Name 12 One NBZD 620.31 0X0AA1 0X00F1 Digital 21 Channel Name / Service Location 12 5 NBZ-S 620.31 0X0AA1 0X00F2 Digital 22 Channel Name / Service Location 12 12 NBZ-M 620.31 0X0AA1 0X00F3 Digital 23 Channel Name / Service Location 12 31 NBZ-H 620.31 0X0AA1 0X00F8 Digital 24 Channel Name / Service Location

Table 1 shows an example of TVCT, and the major channel number of the broadcaster is allocated to 12, and the minor channel number is arbitrarily assigned to the broadcaster, such as 0,1,5,12,31.

However, in order to change the current analog terrestrial broadcasting to digital terrestrial broadcasting, both the broadcasting equipment and the TV receiver have to be changed, which requires a lot of time, so it is very likely that analog terrestrial broadcasting and digital terrestrial broadcasting will coexist for a certain period of time.

Therefore, until the digital broadcasting system is completely established, it is expected that analog / digital TVs capable of simultaneously receiving analog terrestrial and digital terrestrial waves will become the mainstream. The system receiving different broadcasting systems is expected to overcome many obstacles in order to improve broadcasting quality. Among them, channel automatic tuning that is performed independently between two broadcasting systems is pointed out as one of the obstacles.

Hereinafter, an automatic channel tuning apparatus and method for terrestrial / satellite broadcasting TV according to the prior art will be described with reference to the accompanying drawings.

1 is a block diagram showing the configuration of a terrestrial / satellite TV according to the prior art, and FIG. 2 is a flowchart showing the automatic channel tuning method of FIG.

As shown in FIG. 1, a terrestrial / satellite TV according to the related art is a satellite broadcast tuner 1 for selectively receiving a predetermined frequency band among satellite broadcast signals, and a broadcast signal received by the satellite broadcast tuner 1. A demultiplexer (2) for demultiplexing the signal into video, audio, and various control signals, an A / V decoder (3) for decoding audio signals and video signals, an NTSC encoder (4), and a predetermined frequency band among analog terrestrial broadcast signals. A terrestrial tuner 5 for selectively receiving a signal, an IF unit 6 for demodulating an intermediate frequency component among broadcast signals received through the terrestrial tuner 5, a microcomputer 11, the NTSC encoder 4 or an IF unit ( A switching unit 7 for selectively switching the output of 6), a display unit 8 for performing a series of signal processing for displaying satellite or analog terrestrial broadcasting output through the switching unit 7 on a screen; External scene such as VTR or audio A is composed of an external input unit (9) for input.

The automatic channel tuning operation of the terrestrial / satellite broadcasting TV configured as described above will be described with reference to FIG. 2.

Channel number Channel Information Broadcast format One… I A (1) = tuning frequency A (I) = tuning frequency Analog terrestrial broadcast m… p S (m) = network ID / repeater number / channel number… S (p) = network ID / repeater number / channel number Satellite broadcasting

First, when the user selects the automatic channel tuning mode (S11), the microcomputer 11 determines the broadcast mode selected by the user (S12), and when the user selects the terrestrial broadcasting, as shown in Table 2, the analog terrestrial wave channel The channel information allocated to (1 to I), that is, the tuning frequency is sequentially given to the terrestrial tuner 5, and the terrestrial broadcasting channel in which the broadcast signal exists is stored in the memory 12 to complete the automatic channel tuning.

On the other hand, in the determination result (S12), if the user selects the satellite broadcast channel information assigned to all satellite channels (m ~ p), that is, network ID / repeater number / channel number to the satellite broadcast tuner 1 in sequence The satellite broadcasting channel in which the broadcast signal exists is stored in the memory 12 to complete automatic channel selection.

As a result, in order to automatically tune satellite and terrestrial broadcasts, it is necessary to select each mode using a separate hot-key and perform channel auto tuning for all channels of the selected mode.

In the conventional terrestrial / satellite broadcasting TV, the automatic channel tuning method has the following problems.

First, for the automatic channel selection, the user has to select the terrestrial wave and satellite broadcasting modes by using a separate key.

Second, it takes a long time because it automatically performs channel selection for all channels of terrestrial and satellite broadcasting.

Accordingly, an object of the present invention is to provide an analog / digital TV automatic channel tuning apparatus and method for quickly and easily performing automatic channel tuning.

1 is a block diagram showing the configuration of a terrestrial / satellite TV according to the prior art

2 is a flowchart showing the automatic channel tuning method of FIG.

Figure 3 is a block diagram showing the configuration of the analog / digital TV according to the present invention

4A and 4B are block diagrams illustrating the configuration of the analog broadcast signal detector and the digital broadcast signal detector of FIG. 3.

5 is a flowchart illustrating an automatic channel tuning method for analog / digital TV according to the present invention.

6 is a diagram showing the frequency spectrum of the ATSC and NTSC broadcast signals;

7 is a diagram illustrating an example of broadcasting channel allocation.

Explanation of symbols for main parts of the drawings

31: digital tuner 32: digital intermediate frequency demodulator

33: demodulator 34: demultiplexer

35: A / V decoder 36: first memory

37: digital broadcast signal detector 38: analog tuner

39: analog intermediate frequency demodulation part 40: first switching unit

41: NTSC encoder 42: A / D converter

43: second switching unit 44: display unit

45: second memory 46: analog broadcast signal detection unit

47: external input unit 48: microcomputer

In the automatic channel tuning apparatus for analog / digital TV according to the present invention, an analog broadcast signal for determining whether an analog broadcast signal exists in a channel selected in the analog tuner according to whether or not a synchronization signal of the signal output from the analog intermediate frequency demodulator is present. A discriminating unit, a digital broadcasting signal discriminating unit for determining whether a digital broadcasting signal exists in a channel selected by the digital tuner according to whether the signal frequency output from the digital intermediate frequency demodulation unit is locked, and an analog tuner and a digital tuner. Including a microcomputer to provide a frequency for each analog broadcast channel and digital broadcast channel tuning for the broadcast channel and to store the broadcast format and program information of the corresponding channel in the memory according to the output of the analog broadcast signal discrimination unit and the digital broadcast signal discrimination unit Characterized in that configured.

In the automatic channel tuning method of analog / digital TV according to the present invention, when the user selects the automatic channel tuning mode, the microcomputer sequentially outputs respective tuning data for all broadcasting channels to the analog tuner and the digital tuner, and the analog tuner. And receiving, by the digital tuner, a signal corresponding to the preset data output from the microcomputer and determining whether an analog broadcast signal or a digital broadcast signal exists in the current channel through a series of signal processing, and the result of the determination. And storing the corresponding channel as an analog broadcast channel or a digital broadcast channel and storing the corresponding program information.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the automatic channel tuning apparatus and method of the analog / digital TV according to the present invention.

Figure 3 is a block diagram showing the configuration of the analog / digital TV according to the present invention, Figures 4a and 4b is a block diagram showing the configuration of the analog broadcast signal detector and the digital broadcast signal detector of Figure 3, Figure 5 according to the present invention Flow chart showing an automatic channel tuning method of analog / digital TV, FIG. 6 is a diagram showing a frequency spectrum of ATSC and NTSC broadcast signals, and FIG. 7 is a diagram showing an example of broadcasting channel allocation.

As shown in FIG. 3, the analog / digital TV according to the present invention demodulates a digital tuner 31 for selectively receiving a predetermined frequency band among digital broadcast signals and an intermediate frequency component among the signals received through the digital tuner 31. Digital intermediate frequency demodulator 32, demodulator 33 for demodulating the modulated broadcast signal into the original signal, demultiplexer 34 for separating the multiplexed broadcast signal into video / audio and various control signals, voice And a digital broadcast signal discrimination unit 37 for determining whether a digital broadcast signal is output according to an output of the A / V decoder 35, a first memory 36, and the digital intermediate frequency demodulator 32, which decodes an image. A second channel for selectively switching an output of an analog tuner 38, an analog intermediate frequency demodulator 39, an analog intermediate frequency demodulator 39, or an external input unit 47 for selectively receiving a predetermined frequency band among analog broadcast signals; First switching unit 40, NTSC decoder 41, A / D converter 42, second switching for selectively switching the output of the A / D converter 42 or the output of the A / V decoder 35 Unit 43, a display unit 44 for performing a series of signal processing for displaying the output of the second switching unit 43 on the screen, the second memory 45, the analog intermediate frequency demodulation unit 39 The analog broadcast signal discrimination unit 46, the analog tuner 38, and the digital tuner 31 sequentially provide tuning frequencies for all channels according to the output of the analog broadcast signal discrimination unit. And a microcomputer 48 for storing the corresponding channel as an analog or digital broadcast channel in accordance with the output of the digital broadcast signal determination unit 37.

At this time, the digital broadcast signal discrimination unit 37 passes the output frequency of the SAW filter 51, the voltage controlled oscillator 54, and the SAW filter 51 passing only the intermediate frequency component at the output of the digital intermediate frequency demodulator 32. The comparator 52 outputs a voltage corresponding to the difference in the output frequency of the voltage controlled oscillator 54, and the low pass filter 53 which passes only a low pass component of the output of the comparator 52 and supplies it to the voltage controlled oscillator 54. PLL lock detection unit 55 for detecting whether or not the output of the low pass filter 53 is locked within a predetermined phase range.

In addition, the analog broadcast signal discriminator 46 passes only the intermediate frequency component at the output of the analog intermediate frequency demodulator 39, and a video signal for demodulating the video signal component at the output of the SAW filter 61. The demodulator 62 and the sync signal detector 63 detect the presence / absence of the sync signal at the output of the video signal demodulator 62.

The automatic channel tuning method of the analog / digital TV configured as described above is as follows.

First, when the user selects the automatic channel tuning mode through the operation panel installed on the remote control or the TV main body (S31), the microcomputer 48 converts the respective tuning data for the first channel among all broadcasting channels to the analog tuner 38 and the digital. Simultaneously output to the tuner 31 (S32).

In this case, as shown in FIG. 6, in the case of the analog NTSC method, when looking at the frequency spectrum, a picture carrier exists at a point 1.25 MHz away from the channel start frequency, and in the case of the digital ATSC method, the frequency spectrum is described. The pilot signal is present at 0.31MHz from the channel start frequency.

7 is a diagram illustrating an example of allocating a broadcast channel, in which two channels are allocated an NTSC analog channel having a channel start frequency of 54 MHz, four channels are allocated an ATSC digital channel having a channel start frequency of 66 MHz, and the like. NTSC and ATSC channels are allocated at intervals of 6 MHz from the first 54 MHz channel.

NTSC and ATSC schemes can be distinguished according to the above-described frequency spectrum characteristics, that is, the presence / absence of picture carriers and pilot signals present at specific positions.

Therefore, in case of NTSC, 55.25MHz, which adds the start channel 54MHz to 1.25MHz of the picture carrier, is selected as the tuning data.In the case of ATSC, 54.31MHz that adds the start frequency 54MHz of the pilot signal to 0.31MHz Set as the preset data, and simultaneously transmits each preset data to the analog tuner 38 and the digital tuner 31.

Subsequently, it is determined whether the signal received in the current channel is a digital broadcast signal (S33). If the signal received in the current channel is a digital broadcast signal, the current channel is stored as a digital channel (S34), and the information of the broadcast signal is interpreted. Program data is stored (S35).

At this time, the detailed operation of digital broadcast signal determination is as follows.

The digital tuner 31 receives the tuning data transmitted from the microcomputer 48, that is, a signal of a frequency band corresponding to 54.31 MHz, and demodulates an intermediate frequency component of the signal received by the digital intermediate frequency demodulator 32.

In addition, the SAW filter 51 of the digital broadcasting signal discrimination unit 37 extracts the intermediate frequency of the input signal, and the comparator 52 outputs the difference frequency between the intermediate frequency and the output frequency of the voltage controlled oscillator 54 to generate a low pass filter. If the filtering is performed through the reference numeral 53 and the filtering value is locked within the predetermined phase range by the PLL lock detection unit 55, the microcomputer 48 determines that the digital broadcasting signal is the digital broadcast signal.

However, as shown in FIG. 7, since the first channel is two channels and the NTSC method, that is, the analog channel, the pilot signal does not exist in the 54.31 MHz band and the picture carrier exists in the 55.25 MHz band. The intermediate frequency is not detected and the output of the comparator 52 has a large difference from the oscillation frequency of the voltage controlled oscillator 54 so that the output voltage of the low pass filter 53 is high and its phase is constant in the PLL lock detector 55. It is determined that it is not a digital broadcast signal because it cannot be locked.

On the other hand, the determination result (S33), it is determined whether the signal of the current channel is an analog broadcast signal if not the digital broadcast signal (S36).

At this time, the analog broadcast signal determination detailed operation is as follows.

The analog tuner 38 receives the tuning data transmitted from the microcomputer 48, that is, a signal of a frequency band corresponding to 55.25 MHz, and demodulates an intermediate frequency component of the signal received from the analog intermediate frequency demodulator 39.

The SAW filter 61 of the analog broadcast signal discrimination unit 46 extracts the intermediate frequency of the input signal, and the image signal demodulator 62 demodulates the video signal of the intermediate frequency.

Subsequently, when the synchronization signal detection unit 63 detects a synchronization signal among the video signals, the microcomputer 48 determines that it is an analog broadcast signal.

In this case, since the first channel is two channels and is an NTSC method, that is, an analog channel, a picture carrier exists in the 55.25 MHz band, and thus a synchronization signal is detected as a result of signal processing and is determined to be an analog broadcast signal, thereby storing the corresponding channel as an analog channel (S37).

When the channel determination step is completed (S33 to S37), the microcomputer 48 transmits the tuning data of the next channel, that is, three channels, to the analog tuner 38 and the digital tuner 31 to determine the channel determination step (S33 to S37). Retry).

In this case, the channel selection data of 3 channels is the same as the 2 channels, and in case of NTSC system, 61.25MHz which is the sum of the initial channel start frequency 60MHz and the picture carrier distance frequency 1.25MHz is set as the channel data. Is set to 60.31 MHz, which is the sum of the distance frequency 0.31 MHz of the pilot signal, and the channel selection data is set for the other channels by the same method.

Subsequently, when the automatic channel tuning process is completed by performing the tuning data transmission and channel determination steps S33 to S37 to the last channel, that is, the N + 1 channel, the channel information of all channels is stored as shown in Table 3.

Therefore, as shown in Table 3, since the channel information for all channels is completed, the user can watch the analog channel and the digital channel only with the channel up / down key without a separate key operation, that is, without selecting the analog / digital broadcasting mode.

Channel number Channel Information Broadcast format 2344-1... 4-4566-1... 6-4.. … NN + 1 (N + 1) -1... (N + 1) -4 A (2) = Tuning frequency A (3) = Tuning frequency D (4) = Tuning frequency D (4-1) = Broadcasting station and program information. D (4-4) = broadcasting station and program information A (2) = preset frequency D (6) = preset frequency D (6-1) = broadcasting station and program information. D (6-4) = Broadcasting station and program information. … A (N) = Tuning frequency D (N + 1) = Tuning frequency D [(N + 1) -1] = Broadcasting station and program information. D [(N + 1) -4] = Broadcasting station and program information NTSCNTSCATSCNTSCATSCNTSCATSC

The automatic channel tuning apparatus and method for analog / digital TV according to the present invention has the following effects.

First, it is possible to perform automatic channel memory for all broadcasting channels with only one key input without the need for separate input mode selection, and at the same time, users can watch analog and digital broadcasting programs that users want by only inputting channel up / down keys. It can increase convenience.

Second, it accurately grasps the analog / digital broadcasting method of each channel using the frequency spectrum characteristics of NTSC and ATSC methods, so that the time required for channel tuning is completed by completing channel tuning and memory operation with only one channel search for all channels. It can be minimized.

Claims (6)

In an analog / digital TV with a digital tuner, analog tuner, digital mid-frequency demodulator, analog mid-frequency demodulator and memory, An analog broadcast signal discrimination unit for determining whether an analog broadcast signal exists in a channel selected by the analog tuner according to whether or not a synchronization signal of the signal output from the analog intermediate frequency demodulator is present; A digital broadcast signal discrimination unit for determining whether a digital broadcast signal exists in a channel selected by the digital tuner according to whether the signal frequency output from the digital intermediate frequency demodulator is locked; Provide the analog tuner and digital broadcast channel tuning frequencies for all broadcast channels to the analog tuner and the digital tuner, and broadcast format and program information of the corresponding channel according to the output of the analog broadcast signal discriminator and the digital broadcast signal discriminator. Automatic channel tuning apparatus for analog / digital TV, characterized in that it comprises a microcomputer to store in the memory. The method of claim 1, The analog broadcast signal discrimination unit is a SAW filter for passing only the intermediate frequency components at the output of the analog intermediate frequency demodulator; A video signal demodulator for demodulating a video signal component at an output of the SAW filter; And a synchronization signal detection unit for detecting the presence / absence of the synchronization signal from the output of the image signal demodulator and outputting the synchronization signal to the microcomputer. The method of claim 1, The digital broadcast signal discrimination unit is a SAW filter for passing only the intermediate frequency components at the output of the digital intermediate frequency demodulator; A voltage controlled oscillator, A comparator for outputting a voltage corresponding to a difference between an output frequency of the SAW filter and an output frequency of the voltage controlled oscillator; A low pass filter for supplying only the low pass component of the output of the comparator to the voltage controlled oscillator; And a PLL lock detector which detects whether the output of the low pass filter is locked within a predetermined phase range and outputs it to the microcomputer. In analog / digital TV with microcomputer, analog tuner, digital tuner, Sequentially outputting respective tuning data for all broadcast channels to the analog tuner and the digital tuner by the microcomputer when the user selects the automatic channel tuning mode; Receiving a signal corresponding to the preset data output from the microcomputer at the analog tuner and the digital tuner and determining whether an analog broadcast signal exists or a digital broadcast signal exists in the current channel through a series of signal processing; And storing the corresponding channels as an analog broadcasting channel or a digital broadcasting channel according to the determination result and storing the corresponding program information. The method of claim 4, wherein In the step of sequentially outputting the respective tuning data for the all broadcasting channels, the tuning data of the digital tuner among the respective tuning data adds the distance frequency of the pilot signal from the channel start frequency of the ATSC broadcasting frequency to the frequencies of all channels. Automatic channel tuning method of analog / digital TV, characterized in that one frequency. The method of claim 4, wherein In the step of sequentially outputting the respective tuning data for the all broadcasting channels, the tuning data of the analog tuner among the respective tuning data adds the distance frequency of the picture carrier present from the channel start frequency of the NTSC broadcasting frequency to the frequencies of all channels. Automatic channel tuning method of analog / digital TV, characterized in that one frequency.