Digital broadcast signal reproducing system and method

A digital broadcast signal reproducing system including a first board having a tuner receiving a digital broadcast signal; a second board removably combined with the first board, the second board having a demodulator demodulating the digital broadcast signal into an analog signal and a memory storing information on a broadcasting mode therein; and a device driver controlling the tuner and the demodulator, and various chip sets according to the information on the broadcasting mode stored in the memory. With this configuration, a digital broadcast signal reproducing system and method thereof are economical for a manufacturer and a consumer because only a part thereof depending upon a broadcasting system is changed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application No. 2001-62206, filed Oct. 9, 2001, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a digital broadcast signal reproducing system and method thereof, and more particularly, to a digital broadcast signal reproducing system having a digital broadcast signal receiving unit and a broadcast signal reproducing method using the system, which can be used regardless of the kinds of a broadcast signal.

2. Description of the Related Art

Generally, a broadcast signal receiving card is employed for reproducing a broadcast signal through a computer system.

Most of the broadcast signal receiving cards have the same configuration regardless of whether the broadcast signal receiving card receives an analog signal or a digital signal. The broadcast signal receiving card is comprised of a tuner for receiving a broadcast signal responding to a selected channel, an IF (Intermediate Frequency) filter converting the broadcast signal selected by the tuner to be within an IF band, a demodulator demodulating the broadcast signal outputted from the IF filter, and a decoder decoding both a video signal and an audio signal from the broadcast signal demodulated by the demodulator.

Further, there are various methods of reproducing the broadcast signal. A PCI (peripheral component interface) method is widely used In the PCI method, the broadcast signal receiving card converts the broadcast signal into a digital signal, and outputs the digital signal to a memory of a graphic card through a PCI bus. Device drivers are provided in the computer system for operating hardware components, and particularly a device driver of the broadcast signal receiving card detects the broadcast signal receiving card for an operating system, and drives the broadcast signal receiving card to output the video and audio signals from the digital signal received through the PCI bus to the graphic card and a sound card, respectively.

Recently, a broadcast signal receiving card, which can be used for a digital broadcast, is being developed in line with a digital broadcasting service. Representative examples of a broadcasting mode for the digital broadcast include, an ATSC (advanced television standard committee) mode, which was chosen in North America, and a DVB (digital video broadcast) mode, which was chosen in Europe. However, the ATSC mode and the DVB mode are different in the IF bands thereof. Further, in the case of the same DVB modes, IF bands are somewhat different.

Therefore, the computer system must have a different broadcast signal receiving card comprising a demodulator and a decoder suitable for the broadcasting mode depending on a locality. That is, the broadcast signal receiving card should be adaptable in response to either the ATSC mode or the DVB mode.

Accordingly, a lot of time and effort is required to develop a demodulator and a decoder, which is suitable for a broadcasting mode. Also to replace the broadcast signal receiving card with a new one whenever the computer system is used in places with a different broadcasting mode is uneconomical.

Consequently, development of a broadcast signal receiving card, which can be used regardless of the broadcasting mode, is needed.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a digital broadcast signal reproducing system having a digital broadcast signal receiving unit and method thereof, which can be used regardless of a broadcasting mode.

This and other objects of the present invention may be accomplished by a digital broadcast signal reproducing system comprising a first board having a tuner receiving a digital broadcast signal; a second board removably combined with the first board, and having a demodulator demodulating the digital broadcast signal into an analog signal and a memory storing information on a broadcasting mode therein; and a device driver controlling the tuner, the demodulator, and various chip sets according to the information on the broadcasting mode stored in the memory.

Preferably, the device driver has information on an IF band standard according to the broadcasting mode, and sets up a frequency band of a broadcast signal to be tuned by the tuner, a frequency band of the broadcast signal to be demodulated by the demodulator, and frequency bands of video and audio signals decoded by the decoder on the basis of the IF band standard according to the broadcasting mode.

According to another aspect of the present invention, the above and other objects may be achieved by a method of reproducing a digital broadcast signal through a computer, said computer comprising a first board having a tuner receiving the digital broadcast signal within the computer; and a second board having a demodulator demodulating the digital broadcast signal from the tuner into an analog signal and a memory storing information on a broadcasting mode therein to the first board, comprising loading information on a broadcasting mode stored in the memory; and setting up the tuner, the demodulator, and various chip sets according to the information on the broadcasting mode stored in the memory.

Preferably, the setting includes setting up a frequency band of the broadcast signal to be tuned by the tuner; setting up a frequency band of the broadcast signal to be demodulated by the demodulator; and setting up a frequency bands of video and audio signals to be decoded by the decoder.

According to another embodiment of the present invention, the above and other objects may be achieved by a digital broadcast signal receiving device comprising a first board having a tuner receiving a digital broadcast signal, a second board removably combined to the first board and having a demodulator demodulating the digital broadcast signal into an analog signal and a memory storing information on a broadcasting mode therein.

Preferably, the information on the broadcasting mode stored in the memory includes the name of a country transmitting a digital broadcast signal to be demodulated by the demodulator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

A digital broadcast signal reproducing system according to an embodiment of the present invention has a broadcast signal receiving card, which can be used regardless of a broadcasting mode.

As shown inFIG. 1, a digital broadcast signal reproducing system comprises a computer3processing a digital broadcast signal, and an output device20outputting the processed digital signal to the outside.

The computer3includes a broadcast signal receiving card10receiving the digital broadcast signal, and a device driver5controlling the broadcast signal receiving card10.

As shown inFIG. 2, the broadcast signal receiving card10is comprised of a first board11, and a second board15removably combined with the first board11and having a demodulator17.

On the first board11are provided a tuner12receiving a broadcast signal responding to a selected channel, an IF filter13converting the broadcast signal selected by the tuner12to be within an IF band, a demultiplexer18dividing an analog broadcast signal demodulated by a demodulator17into a video signal and an audio signal, and a decoder14decoding the video signal and the audio signal. Herein, the decoder14has a video decoding part14afor decoding a video signal compressed by a compression standard like an MPEG-2 (moving picture experts group2), and an audio decoding part14bdecoding an audio signal compressed by a compression standard like an AC-3 (Digital Audio AC-3).

On the second board15are provided the demodulator17demodulating a digital broadcast signal outputted from the tuner12into an analog signal, and a memory19storing information on the broadcasting mode. The memory19is comprised of an EEPROM (electrically erasable read-only memory).

Specifically, on the second board15is provided either a VSB (vestigial side band) board15ahaving a VSB demodulator17ademodulating a broadcast signal of an ATSC mode, or a COFDM board15bfor a COFDM demodulator17bdemodulating a broadcast signal of a DVB mode. In the memory19for the VSB board15ais stored information on the VSB demodulator17ademodulating a broadcast signal of the ATSC mode used in North America, and in the memory19for the COFDM board15bis stored information on the COFDM demodulator17bdemodulating a broadcast signal of the DVB mode used in Europe. Therefore, to the first board11is selectively combined the VSB board15afor the ATSC mode used in North America, or the COFDM board15bfor the DVB mode used in Europe.

As shown inFIG. 3, to control the broadcast signal receiving card10, the device driver5communicates with the broadcast signal receiving card10through a PCI bus. Under an operating system, the device driver5detects the broadcasting mode stored in the memory19, and then determines which board, the VSB board15a(shown inFIG. 2) or the COFDM board15b(shown inFIG. 2), is employed as the second board15of the broadcast signal receiving card10. Further, the device driver5controls the tuner12, the demodulator17and the decoder14on the basis of the second board15according to the broadcasting mode.

Therefore, the device driver5has information on an IF band standard of the video and audio signals according to the broadcasting mode, as in the following <Table 1>.

Thus, the device driver5loads the IF band standard according to a broadcasting mode stored in the memory19, sets up a frequency band of a broadcast signal to be tuned by the tuner12, and sets up a frequency band of the broadcast signal to be demodulated by the demodulator17. According to the change in the frequency band of a broadcast signal to be demodulated by the demodulator17, the IF bands of the video and audio signals, which are divided by the demultiplexer18, are changed, so that the device driver5changes a frequency band of the decoder14corresponding to the IF bands of the video and audio signals.

Referring toFIGS. 1-3, the output device20includes a display apparatus23outputting the video signal, and a speaker27outputting the audio signal. To output the video and audio signals, the computer3has a graphic card21outputting the video signal decoded by the video decoding part14ato the display apparatus23, and a sound card25outputting the audio signal decoded by the audio decoding part14bto the speaker27.

Next, the process of reproducing the digital broadcast signal through a digital broadcast reproducing system will be described, referring toFIG. 4.

First, electric power is supplied to the computer3(S10), and the device driver5loads the information stored in the memory19of the broadcast signal receiving card10through the PCI bus and determines a broadcasting mode of the broadcast signal receiving card10, under the operating system (S20). In other words, the broadcast signal receiving card10determines which board, either the VSB board15aor the COFDM board15bis employed as the second board15of the broadcast signal receiving card10.

If the VSB board15ais employed as the second board15, the device driver5sets up the frequency bands of the demodulator17and the decoder14corresponding to the video IF band of 38.9 MHz and the audio IF band of 5.5 MHz shown in the ATSC mode of <Table 1>, respectively (S30). Then, the device driver5sets up the tuner12so as to tune channels suitable for the IF band standard (S40).

If the COFDM board15bis employed as the second board15, the device driver5sets up the frequency bands of the demodulator17and the decoder14corresponding to the video IF band of 45.75 MHz and the audio IF band of 4.5 MHz shown in the DVB mode of <Table 1>, respectively (S35). Then, the device driver5sets up the tuner12so as to tune channels suitable for the IF band standard (S40).

After the setting is completed, the digital broadcast signal receiving card10processes a broadcast signal according to the broadcasting mode. That is, if the broadcast signal receiving card10receives a broadcast signal, then the tuner12tunes a frequency band corresponding to the channel selected by a user, and the IF filter13converts the broadcast signal tuned by the tuner12to be within the IF band. Thereafter, the demodulator17demodulates the broadcast signal within the IF band, and the demultiplexer18divides the demodulated broadcast signal into the video signal and the audio signal. The video and audio signals are decoded by the video and audio decoding parts14aand 14b,respectively. The decoded video signal is displayed on the display apparatus23through the graphic card21. The decoded audio signal is outputted to the speaker27through the sound card25.

As described above, in the digital broadcast signal reproducing system according to an embodiment of the present invention, the broadcast signal receiving card10comprises the first board11having the tuner12and the decoder 14, and the second board15having the demodulator17and the memory19. At this time, the second board is manufactured according to the ATSC broadcasting mode for the VSB demodulator and the DVB broadcasting mode for the COFDM demodulator, respectively. Therefore, contrary to the conventional broadcast signal receiving card, without replacing the broadcast signal receiving card10with a new one, the first board11thereof is commonly used and only the second board15thereof is changed when the broadcasting mode is changed. Consequently, the manufacturing cost and efforts thereof are required only when the second board15is changed.

As described above, the present invention provides a digital broadcast signal reproducing system and method, which is economical for both a manufacturer and a consumer because only a part thereof depending upon a broadcasting system is changed.