KR100469285B1 - Apparatus for generating digital TV signal - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital TV signal generating device. In particular, the data uploaded from an HDD is decoded through an A / V decoder and then output as an analog audio / video signal. In addition, many vendors developing ATSC-related DTV receivers get RF signals and transport streams that comply with the ATSC standard at a lower cost, and can be developed on a standard PC basis. In addition, digital TV playback, which could only be played on existing HD Ready monitors, can be transferred to built-in sets and set top boxes that can receive RF.

Description

Apparatus for generating digital TV signal

The present invention relates to an apparatus for receiving a digital broadcast and reproducing a transport (TP) stream stored in a storage medium.

The National Television Standards Committee (NTSC) has been in use for decades in television transmission, and has come into the age of coexistence with digital TV in the coming years as the digital TV era has come. The digital TV has a North American standard and a European standard, and the North American standard follows the standard of the Advanced Television Systems Committee (ATSC). Korea follows the ATSC standard, the North American standard.

At this time, a method of receiving and storing high definition (HD) -class digital broadcasts includes a PC card and a personal video recorder (PVR) set top box. In the current method, a digital stream stored in a storage medium (for example, a HDD of a PC) can be simply played to reproduce analog audio and video.

1 is a block diagram of a general configuration of an apparatus for reproducing a digital TV stream stored in an HDD in the form of a PC card, wherein a digital broadcasting signal (for example, an ATSC signal) received from an antenna is used as a digital broadcasting standard (VSB). The VSB demodulator 101 demodulates and outputs the TP stream in the form of a TP stream, and after separating the TP stream output from the VSB demodulator 101 into an audio and video stream, the video stream is a reverse process of video coding. A / V decoder 102, which performs decoding (e.g. MPEG-2 decoding) and the audio stream performs decoding (e.g., Dolby AC-3 decoding) in the reverse of audio coding. The HDTV monitor receives the external memory (e.g., SDRAM) 105 necessary for performing MPEG-2 decoding at the V decoder 102 and the MPEG-2 decoded video data at the A / V decoder 102. Convert to analog video format The video output unit 107 outputs the digital audio signal decoded by the A / V decoder 102, and the analog audio unit 108 outputs the analog signal.

The NTSC signal received through the antenna or the NTSC signal input through the external input terminal is output to the NTSC video decoder 104 and the analog video signal (for example, the PC video signal) input through the external input terminal. Is output to the analog video decoder 103. The NTSC video decoder 104 or the output of the analog video decoder 103 is output to the video output unit 107 and the analog audio unit 108 through the A / V decoder 102.

The A / V decoder 102 may perform MPEG-2 decoding by uploading a TP stream stored in the HDD of the PC through a Peripheral Component Interconnect (PCI) bus provided from the PC.

The output of the A / V decoder 102 is also output to the VGA card 110 and the analog switch unit 106, and the VGA card 110 outputs the RGB signal for the VGA to the analog switch 106. The analog switch 106 selects an HD-level RGB signal output from the A / V decoder 102 or an RGB signal for VGA output from the VGA card 110 and outputs the same to the PC.

The operation of the PC card configured as described above is performed in the following two forms.

First, after the power is applied to the system, the user selects the desired broadcast channel, and the tuner (not shown) tunes the RF signal of the selected broadcast channel to downmix to an intermediate frequency (IF). After that, it outputs to the VSB demodulator 101. The ATSC / NTSC unit of the VSB demodulator 101 outputs to the VSB receiver if the down mixed IF signal is a digital broadcast signal, and to the NTSC decoder 104 if it is an analog broadcast signal. The VSB receiver detects a carrier from the digital broadcast signal, decodes a coded signal made by an RF transmitter, and transmits the decoded signal to the A / V decoder 102 in the form of a TP stream. The A / V decoder 102 parses the TP stream to separate audio and video streams, and the separated video stream is subjected to variable length decoding (VLD) using an SDRAM 105 and then dequantized (IQ). The inverse discrete cosine transform (IDCT) process and the motion compensation (MC) process are used to restore the original pixel values. Similarly, the audio stream decodes (eg, Dolby AC-3) in the reverse process of audio coding. The video output unit 107 converts the MPEG-2 decoded video data by the A / V decoder 102 into an analog video format that an HDTV monitor can accept, and outputs the analog audio unit 108 to the A. The digital audio signal decoded and output by the / V decoder 102 is analogized and output to the speaker of the HDTV monitor.

Secondly, the TP stream stored in the HDD of the PC is uploaded to the A / V decoder 102 through the PCI bus provided by the PC. In this case, the A / V decoder 102 does not decode the TP stream output from the VSB demodulator 101, decodes the TP stream uploaded through the PCI bus, and then the video processor 107 and the analog audio unit 108. )

As described above, the conventional technology has only a method of receiving and decoding an RF signal transmitted from a broadcasting station, or decoding and storing data stored in an HDD, which is a storage medium, to output analog audio and video.

That is, with the advent of the digital TV era, the development of digital TV-related devices is in progress. Therefore, companies developing DTV-related devices should be equipped with an ATSC RF generator to generate the ATSC standard RF signal required for the development, test, after service, and demonstration of a set.

However, the general ATSC RF generator is expensive and the equipment is large and inconvenient to move, and is complicated in various aspects such as installation and usage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus for generating a digital TV signal to support RF output by performing 8VSB modulation in a general purpose PC without an additional system.

Another object of the present invention is to provide a digital TV signal generating apparatus for outputting a VSB modulated RF signal simultaneously with an analog audio / video signal for an HDTV monitor in a general purpose PC.

1 is a block diagram of a general configuration of an apparatus for reproducing a digital TV stream stored in an HDD in the form of a PC card.

2 is a block diagram of a digital TV signal generating apparatus according to the present invention;

3 is a flowchart illustrating a digital TV signal generation process according to the present invention.

4 is an operation timing diagram of each part of FIG.

Explanation of symbols for main parts of the drawings

200: digital TV signal generator 201: tuner and VSB demodulator

202: PCI control unit 203: PCI / TP interface logic unit

204: A / V decoder 205: SDRAM

206: Video DAC 207: Audio DAC

208: VSB remodulation unit

The digital TV signal generating apparatus according to the present invention for achieving the above object is a tuner and VSB demodulator for receiving a digital broadcast signal that is being broadcast from a broadcasting station and demodulating and outputting it as a transport stream, mounted on a general PC A storage medium storing an MPEG compressed stream, and a PCI / TP interface for reading an MPEG compressed stream from the storage medium and converting the MPEG compressed stream into an ATSC standard transport stream when a data request is inputted. After the audio signal and the video signal are separated from the logic unit and the transport stream output from the tuner and the VSB demodulation unit or the PCI / TP interface logic unit, the separated audio signal performs audio decoding using an AC-3 algorithm. Signals are audio / video signals that are then analogized after performing video decoding using the MPEG-2 algorithm. To the transport stream output from the unit and the tuner and a VSB demodulator or, PCI / TP interface logic unit VSB modulation is characterized in that the configuration includes a VSB remodulation and outputting an RF signal.

The PCI / TP interface logic unit adds a parity and field synchronization of a predetermined byte to the MPEG compressed stream read from the storage medium and converts the stream into an ATSC standard stream.

The PCI / TP interface logic unit is provided with a dual port buffer memory.

When the PCI / TP interface logic unit and the storage medium make a DMA request to request data stored in the storage medium, the MPEG compressed stream from the storage medium through the PCI bus in response to the request. It is characterized in that the PCI control unit further reads.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

2 is a block diagram showing an example of a digital TV signal generating apparatus according to the present invention, which is a storage medium mounted on a general PC, inserted into a general PC in the form of a card, and exchanges data with the HDD through a PCI bus. The receiving DTV signal generator 200 is configured.

The DTV signal generator 200 receives a digital broadcast of a specific channel received through an antenna, performs a VSB demodulation, and outputs a TP stream in the form of a tuner and a VSB demodulator 201 for accessing data stored in the HDD. PCI control unit 202 providing an interface, PCI / TP interface logic unit 203 for converting the TP stream uploaded through the PCI control unit 202 to the ATSC 8VSB standard, the output from the tuner and VSB demodulator 201 A / V decoder 204 and A / V decoder 204 which decode the TP stream or the TP stream output from the PCI / TP interface logic unit 203 into video and audio streams and then decode the data using the decoding memory 205. An external video digital to analog converter (DAC) 206 that analogizes a video signal output from the V decoder 204 and outputs it to an HDTV monitor, and an audio signal output from the A / V decoder 204 is analogized. An external audio DAC 207 outputted to a speaker of an HDTV monitor, a TP stream output from the tuner and the VSB demodulator 201, or a TP stream output from the PCI / TP interface logic unit 203. A VSB remodulation unit 208 modulates an ATSC standard RF signal.

The VSB remodulator 208 may be any one designed to output a VSB RF signal defined in the ATSC standard through VSB modulation.

It is assumed that the storage medium stores the received digital broadcast in the form of an MPEG compressed stream.

The storage medium may be any one capable of storing data, for example, a ROM, a RAM, a flash memory, a hard disk (HDD), or the like may be used. Here, the memory device may be applied to a wider variety of applications, and thus the present invention will not be limited to the above example.

In the present invention, for convenience of description, the storage medium uses a hard disk (HDD), and the hard disk is mounted on a PC according to an embodiment. Here, the body on which the storage medium is mounted may vary depending on which one is used as the storage medium.

3 is a flowchart illustrating a digital TV signal generation process according to the present invention.

In the present invention configured as described above, the powered system (step 301) first receives airwaves to perform A / V decoding and VSB remodulation, uploads the TP stream stored in the PC's HDD, and then reconstructs A / V decoding and VSB. It is determined whether to modulate (step 302).

In case of receiving an air wave, the tuner and the VSB demodulator 201 tune the RF signal of a desired broadcast channel from an antenna, downmix to an intermediate frequency (IF), and perform VSB demodulation before TP. The stream is output to the A / V decoder 204 and the VSB remodulator 208 (step 303).

On the other hand, when uploading and playing back the TP stream stored in the HDD of the PC, the PCI / TP interface logic unit 203 reads the TP stream from the HDD through the PCI control unit 202 and the PCI bus to the A / V decoder 204. ) And the VSB remodulator 208.

That is, in order to request data of the HDD from the direct memory access (DMA) master (not shown) of the PCI / TP interface logic unit 203, a DMA request is made to the PCI controller 202. In response to the request, the PCI control unit 202 sends this signal to the DMA control unit (not shown) of the PC via the PCI bus to start a DMA operation for reading data of the HDD (step 304), and accesses the HDD. (Step 305). The DMA operation started as described above is responded until the DMA master of the PCI / TP interface logic unit 203 stops the request. The TP stream stored in the HDD is synchronized with the PCI clock 33 MHz by the DMA control. It is input to the / TP interface logic section 203 (step 306).

The PCI / TP interface logic unit 203 synchronizes the HDD data transmitted according to the PCI clock 33MHz to 2.69MHz, which is the TP interface clock, and converts the data into an ATSC 8VSB output specification as shown in FIG. 4 (step 307). That is, the PCI / TP interface logic unit 203 uses its own buffer memory to match HDD data transmitted at a high speed PCI clock 33MHz to a speed of 2.69MHz, which is a TP interface clock, and to meet the ATSC 8VSB output specification as shown in FIG. 4. It has an dual port memory, and the data inputted in synchronization with the PCI clock 33MHz is inserted into the buffer memory, and then the data is output in accordance with the TP interface, that is, the ATSC 8VSB standard as shown in FIG. This is because it is difficult to continuously read data at the same speed when the HDD is used as a storage medium, and in particular, it may be unstable during long play, and thus may be stabilized in the PCI / TP interface logic unit 203 to stabilize the data. Leave buffer memory.

If the buffer memory becomes full, the DMA request is suspended for a while, and if there is space to store in the buffer memory, that is, it is necessary to refill part of the buffer memory, the PCI / TP interface logic unit ( The DMA control unit 203 again requests a DMA request to the PC, receives the TP stream from the HDD, and stores the TP stream in the buffer memory.

In this way, the TP stream can be continuously played for a desired time.

In this case, the output of the PCI / TP interface logic unit 203 has the same structure as the output format of the tuner and the VSB demodulator 201. The format of the TP stream output from the tuner and the VSB demodulator 201 is a stream conforming to the ATSC standard, and is output to the A / V decoder 204 and the VSB remodulator 208.

In this case, the TP stream input from the HDD to the PCI / TP interface logic unit 203 is an MPEG-2 compressed stream. The first byte always starts with 0x47, and 188 bytes constitute one packet. In the ATSC 8VSB standard, 208 (= 188 data + 20 parity) bytes with parity and field synchronization added to the MPEG-2 compressed stream constitute one data segment.

Therefore, the PCI / TP interface logic unit 203 adds parity for each packet of the TP stream read from the HDD, converts it into a stream that conforms to the ATSC standard, and then resynchronizes the A / V decoder 204 with the VSB in synchronization with 2.69 MHz. Output to the grandfather 208.

That is, by using the Data_Valid signal of (d) of FIG. 4, which is one of the output control signals of the PCI / TP interface logic unit 203, as shown in (b) and (c) of FIG. If the uploaded valid TP data of uploaded 188Byte is output and null data is output for 20Byte, a stream conforming to the ATSC 8VSB standard is output.

In the present invention, 188 bytes of data + 20 bytes of parity (= 208 bytes) are referred to as one data segment. In addition, the 313th data segment is called field synchronization, and null data 208 bytes are output in the field synchronization section as shown in FIG.

As described above, the TP stream output from the tuner and the VSB demodulator 201 and the TP stream output from the PCI / TP interface logic unit 203 are streams conforming to the ATSC 8VSB standard as illustrated in FIG. 4. When receiving an over-the-air signal, the outputs of the tuner and the VSB demodulator 201 are simultaneously output to the A / V decoder 204 and the VSB remodulator 208, and in the case of HDD uploading, the PCI / TP interface logic. The output of the unit 203 is simultaneously output to the A / V decoder 204 and the VSB remodulator 208.

That is, the output of the PCI / TP interface logic unit 203 is the same signal structure as the TP port signal structure that the A / V decoder 204 accepts the TP stream, which is the VSB re-transformation with the A / V decoder 204 The grandfather 208 simultaneously receives data from the PCI / TP interface logic unit 203 and enables A / V decoding and VSB remodulation, respectively.

The VSB remodulator 208 VSB modulates the data output from the tuner and the VSB demodulator 201 or the data output from the PCI / TP interface logic unit 203 and outputs the RF signal (step 308). That is, the VSB remodulator 208 receives data to be converted into an RF signal, a data valid signal Data_valid, and a 2.69 MHz clock, which is a TP interface clock, from the PCI / TP interface logic unit 203. The data valid signal Data_valid is transferred from the PCI / TP interface logic unit 203 to the VSB remodulation unit 208 so that the VSB remodulation unit 208 can recognize pure data as shown in FIG. As a control signal to be output, it is high during a period of 188 bytes that is pure data, and low during a 20-byte parity period and during a field synchronization period repeated for every 313th data segment. That is, the data valid signal Data_valid is a signal that distinguishes only pure data parts excluding additional data such as a parity signal in one packet, and may be generated by counting from the sync byte starting with Ox47 to 188. This distinguishes the data valid signal since the parity code added to the MPEG transport stream is required only for ECC decoding. The same applies to the field synchronization signal.

The VSB remodulator 208 performs VSB modulation on the ATSC standard TP stream input as shown in FIG. Convert to a signal. In this case, the RF signal may be converted into an analog signal using a DAC and then output to RF channels 3 and 4.

The RF signal output from the VSB remodulator 208 may be used during a test or a demonstration.

The A / V decoder 201 parses an ATSC standard TP stream output from the tuner and the VSB demodulator 201 or an ATSC standard TP stream output from the PCI / TP interface logic unit 203. The video stream is separated into audio and video streams, and the separated video stream is subjected to variable length decoding (VLD) using the SDRAM 205, followed by an inverse quantization (IQ) process, an inverse discrete cosine transform (IDCT) process, and a motion compensation (MC). After the process, the image is restored to the pixel value of the original screen and output to the video DAC 206. Similarly, the audio stream is decoded (eg, Dolby AC-3) in the reverse process of audio coding and output to the audio DAC 207. The video DAC 206 converts the MPEG-2 decoded video data into an analog video format that can be accepted by an HDTV monitor by the A / V decoder 204, and the audio DAC 207 outputs the A / V decoder. The V decoder 102 converts the Dolby AC-3 decoded audio data into an analog audio format that the HDTV monitor can accept and outputs to the speaker of the HDTV monitor or the like (step 309). Here, AC-3 is a method adopted as an audio standard of digital terrestrial TV, and refers to a third type of audio coding method newly developed by Dolby Laboratories in the United States, which is famous for audio noise reduction technology.

As described above, the present invention can store digital broadcasts on a storage medium such as an HDD, and then play data stored on the HDD not only by analog audio and video but also by reproducing it by RF, so that the digital broadcast can be played only on an existing HD Ready monitor. Digital TV playback, which was not available, can be transmitted to built-in sets and set top boxes that can receive RF.

This is essential to conduct the tests required to develop digital TV products and can provide the necessary functions to display all the functions supported by digital TV products.

Therefore, the present invention can be used in all parts requiring the VSB RF signal of the ATSC standard.

As described above, according to the digital TV signal generating apparatus according to the present invention, the data uploaded from the HDD is decoded through an A / V decoder and then output as an analog audio / video signal, and at the same time, the VSB re-modulator complies with the ATSC standard. By outputting VSB RF signals, many vendors developing ATSC-related DTV receivers get RF signals and transport streams that comply with ATSC standards at lower cost, and can be developed on a standard PC basis. In other words, using a general PC ATSC standard RF signal can be generated very easily and inexpensively.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (4)

A tuner and a VSB demodulator for receiving a digital broadcast signal broadcast from a broadcasting station and demodulating the VSB to output the transport stream; A storage medium mounted on a general PC and storing an MPEG compressed stream; A PCI / TP interface logic unit that reads an MPEG compressed stream from the storage medium and converts it into a transport stream of an ATSC standard when a data request is input; After the audio signal and the video signal are separated from the transport stream output from the tuner and the VSB demodulator or the PCI / TP interface logic unit, the separated audio signal is decoded using the AC-3 algorithm and the video signal is MPEG-. An audio / video signal processor configured to perform analog video decoding using two algorithms and then analogize the video; And And a VSB remodulator for outputting an RF signal by VSB modulating the transport stream output from the tuner and the VSB demodulator or the PCI / TP interface logic unit. The logic unit of claim 1, wherein the PCI / TP interface logic unit And a parity and field synchronization of a predetermined byte is added to the MPEG compressed stream read from the storage medium and converted into an ATSC standard stream. The storage device of claim 1, wherein the PCI / TP interface logic unit is disposed between the storage medium and the storage medium. When the PCI / TP interface logic unit makes a DMA request to request data stored in the storage medium, the PCI control unit for reading the MPEG compressed stream from the storage medium through the PCI bus in response to the request is further provided. Digital TV signal generator. The logic unit of claim 1, wherein the PCI / TP interface logic unit A digital TV signal generating device characterized by converting an MPEG compressed stream transmitted according to the PCI clock 33MHz into an ATSC standard transport stream while synchronizing with the TP interface clock 2.69MHz.