KR100404185B1 - Digital TV translator and Method for process error of Digital TV translator - Google Patents

Abstract

The present invention relates to a digital TV repeater, and more particularly, to a digital TV repeater and an error processing method adapted to provide an announcement to a subscriber when an error occurs in a broadcast signal. The error processing method of the digital TV repeater according to the present invention includes a first step of receiving a broadcast signal and outputting it as an intermediate frequency (IF) signal, and extracting the output intermediate frequency (IF) signal to generate a direct current (DC) signal. And a third step of converting the output DC signal into a digital signal and outputting the digital signal, and analyzing the output digital signal to determine whether an error of the received broadcast signal occurs. Step 4 and, if an error occurs in the received broadcast signal according to the determination result, a fifth step of outputting already set video data to a transmitting end, and transmitting the output video data to guide broadcasting. The six-stage process can reduce the subscriber's dissatisfaction, and the system operator recognizes the error of the broadcast signal and promptly It may take action has an effect capable of providing a digital broadcast service of a certain quality.

Description

Digital TV translator and method for process error of Digital TV translator}

The present invention relates to a digital TV repeater, and more particularly, to a digital TV repeater and an error processing method adapted to provide an announcement to a subscriber when an error occurs in a broadcast signal.

In general, the digital TV repeater is for subscribers in the radio shadow area where the broadcast signal does not reach, and serves to increase the viewing rights of the digital TV as a whole.

1 is a block diagram illustrating a conventional digital TV broadcasting system.

Referring to FIG. 1, a digital TV broadcasting system includes a digital broadcast transmitter 100 for transmitting a broadcast signal, a digital TV repeater 101 for relaying a broadcast signal transmitted from the digital broadcast transmitter 100, and the digital broadcast. A first subscriber 102 located around the transmitter 100 and a second subscriber 103 located in the radio shadow area.

The operation of the digital TV broadcasting system configured as described above is as follows.

First, the digital broadcast transmitter 100 transmits a broadcast signal input from a broadcasting station (not shown) to subscribers through the frequency F1.

At this time, the first subscribers 102 located around the digital broadcast transmitter 100 may receive a high quality digital broadcast by directly receiving a broadcast signal through an antenna installed on the roof or a TV antenna embedded in the digital TV.

However, the second subscribers 103 of the astigmatism zone, which are located in a radio wave region such as a mountain or a hill or are far from the digital broadcast transmitter 100 and receive a weak broadcast signal, are transmitted from the digital broadcast transmitter 100. Broadcast signals cannot be received.

In this case, a method of increasing the output of the digital broadcast transmitter 100 may be considered, but it is difficult to realize due to high cost and radio law. Accordingly, a digital TV repeater 101 capable of retransmitting a weak broadcast signal as a strong signal is installed in order to service the visual acuity region at a low cost.

The digital TV repeater 101 may be provided in plural, and the second subscriber of the blind spot region receives a broadcast signal transmitted from the digital broadcast transmitter 100 using a frequency different from that of the digital broadcast transmitter 100, ie, F2, F3, and the like. Relay to (103).

2 is a block diagram illustrating a conventional digital TV repeater.

Referring to FIG. 2, the conventional digital TV repeater receives a demodulated radio frequency (RF) signal transmitted from a digital broadcasting transmitter, demodulates the signal, outputs the MPEG-II transport stream signal, and outputs the output MPEG-II transport stream signal. It consists of a transmitter that up-converts, amplifies, and transmits a frequency of a predetermined channel.

Here, the receiver is a band filter (BPF) 201 for filtering a radio frequency (RF) signal received through the receiving antenna 200, and a low noise for amplifying a radio frequency (RF) signal filtered by the band filter 201. An amplifier (LNA) 202, a variable attenuator (ATT) 203 for adjusting the gain of the radio frequency (RF) signal amplified by the low noise amplifier 202, and a radio frequency output from the variable attenuator 203 A mixer 204 for frequency downconverting the (RF) signal into an intermediate frequency (IF) signal, and an intermediate frequency (IF) filter 205 for filtering the frequency up-converted IF signal in the mixer 204. And an intermediate frequency (IF) amplifier 206 for amplifying the intermediate frequency (IF) signal filtered by the intermediate frequency (IF) filter 205, and an intermediate frequency output from the intermediate frequency (IF) amplifier 206. A saw filter (SAW) 207 that passes only 6 MHz on a 44 MHz basis in an (IF) signal, and the saw A digital demodulator 208 that demodulates an intermediate frequency (IF) signal output from the filter 207 to output a baseband signal, and an analog / digital signal that converts the baseband signal output from the digital demodulator 208 into a digital signal; A converter (ADC) 209 and a digital broadcast decoder 210 that performs channel decoding on digital baseband signals output from the analog / digital converter 209 to correct errors and output an MPEG-II transport stream signal. It is composed of Here, the mixer 204 includes a PLL circuit 218 and a voltage controlled oscillator (VCO) 217 that generate a local oscillation frequency, and a local amplifier that amplifies and filters the generated local oscillation frequency to provide the mixer 204. (AMP) 216 and local band filter (BPF) 215 are connected.

The transmitting end modulates the MPEG-II transport stream signal output from the digital broadcast decoder 210 to output an intermediate frequency (IF) signal, and the intermediate frequency (IF) output from the digital modulator 211. ) Is composed of a transmitter 212 for up-converting and amplifying a signal to a frequency of a predetermined channel and transmitting the same through a transmitting antenna 213.

The digital TV repeater includes a controller 214 that controls each device of the receiving end and the transmitting end, and in particular, the PLL circuit 218 and the analog-to-digital converter (ADC) 209.

The operation of the digital TV repeater configured as described above is as follows.

First, a radio frequency (RF) signal received by the receiving antenna 200 is input to a band filter (BPF) 201. The band filter 201 filters and outputs only a radio frequency (RF) signal of a required band, and the low frequency amplifier (LNA) 202 because the RF signal output from the band filter 201 is weak in intensity. Is amplified. The gain of the radio frequency (RF) signal output from the low noise amplifier 202 is adjusted by the variable attenuator 203 having an automatic gain control (AGC) function.

The mixer 204 then multiplies the radio frequency (RF) signal output from the variable attenuator 203 by the local oscillation frequency and outputs an intermediate frequency (IF) signal of 44 MHz.

Subsequently, the intermediate frequency (IF) filter 205 removes an unnecessary frequency band signal generated by the harmonic from the intermediate frequency (IF) signal output from the mixer 204 and outputs only a signal of 44 MHz, which is a required frequency band.

The intermediate frequency (IF) signal output from the intermediate frequency (IF) filter 205 is then amplified by the intermediate frequency (IF) amplifier 206 and amplified by the intermediate frequency (IF) amplifier 206. The signal is filtered by the saw filter 207 so that only an intermediate frequency (IF) signal in the 44 MHz band is output.

Thereafter, the digital demodulator 208 demodulates the intermediate frequency (IF) signal output from the saw filter 207, converts the signal into a baseband signal, and outputs the baseband signal output from the digital demodulator 208. At 209 it is converted into a digital signal.

Then, the digital broadcast decoder 210 adjusts the sampling period for the ADC operation, performs channel decoding on the baseband signal, and outputs the digital MPEG-II transport stream signal to the transmitter.

The digital modulator 211 of the transmitting end modulates the received MPEG-II transport stream signal into an analog 44 MHz intermediate frequency (IF) signal, and the transmitter 212 outputs an intermediate frequency (output) output from the digital modulator 211. IF) frequency up-converts the signal to a preset channel frequency, amplifies it, and transmits the signal to the blind spot through the transmit antenna 213.

The subscribers in the astigmatism area could not receive the broadcast signal through the existing channel, but they could watch the broadcast of the same quality as the broadcast from the digital broadcast transmitter by receiving the broadcast signal through another frequency channel transmitted by the digital TV repeater. .

However, the conventional digital TV repeater does not have an apparatus for detecting and processing an error of a broadcast signal at a receiving end. Therefore, when an error occurs in the broadcast signal when the digital broadcast transmitter transmits the distorted broadcast signal or when the digital TV repeater receives the broadcast signal, the digital TV transmitter does not process the distorted broadcast signal by itself. There is a problem in that the reception dissatisfaction increases because the subscribers in the astigmatism area do not receive the broadcast signal normally by transmitting to the subscriber.

In addition, the system operator of the digital TV repeater can not quickly know that an error occurs in the broadcast signal, and can not determine whether the cause is due to the digital broadcast transmitter or the digital broadcast repeater, so that it is not able to take appropriate measures promptly, thereby providing a stable digital broadcasting service. There is a problem that can not provide the subscriber.

Accordingly, an object of the present invention has been made in view of the above-mentioned problems of the prior art, to provide a digital TV repeater and error processing method for detecting the occurrence of an error in a broadcast signal and accordingly guide broadcasts to subscribers It is for.

According to a configuration feature of the present invention for achieving the above object, the digital TV repeater includes a filtering unit for receiving a radio frequency (RF) broadcast signal, and a demodulation unit for demodulating the received broadcast signal into a baseband signal; And a modulator for modulating the baseband signal output from the demodulator into an intermediate frequency (IF) signal, and a transmitter for transmitting the intermediate frequency (IF) signal output from the modulator to a predetermined channel frequency. A memory for storing arbitrary image data, a switch for selecting one of the image data stored in the memory and a baseband signal output from the demodulator, and outputting the selected signal to the modulation unit, and a broadcast signal output from the filtering unit. A signal detector for extracting and outputting the direct current (DC) signal, and outputting the output direct current (DC) signal as a digital signal An analog / digital converter, and a controller configured to analyze the output digital signal to determine whether an error of the received broadcast signal occurs, and to control the memory and the switch to transmit image data stored in the memory when an error occurs. It is configured by.

Preferably, it comprises a splitter for separating the broadcast signal output from the filtering unit and outputs to the signal detector or the demodulator.

According to the method feature of the present invention for achieving the above object, the error processing method of the digital TV comprises a first step of receiving a broadcast signal and outputting it as an intermediate frequency (IF) signal, and the output intermediate frequency (IF) A second step of extracting and outputting a signal as a direct current (DC) signal; a third step of converting and outputting the output direct current (DC) signal into a digital signal; and analyzing the output digital signal to receive the received broadcast. A fourth step of determining whether an error occurs in a signal, a fifth step of outputting already set video data to a transmitting end if an error occurs in the received broadcast signal according to the determination result, and the output image data The sixth step of transmitting a guide broadcast.

1 is a block diagram showing a conventional digital TV broadcasting system.

Figure 2 is a block diagram showing a conventional digital TV repeater.

Figure 3 is a block diagram showing a digital TV repeater according to the present invention.

* Description of the symbols for the main parts of the drawings *

300, 315: transmit and receive antenna 301: band filter

302: low noise amplifier 303: variable attenuator

304 Mixer 305 Intermediate Frequency (IF) Filter

306: intermediate frequency (IF) amplifier 307: saw filter

308: Splitter 309: Digital Demodulator

310: second analog-to-digital converter 311: digital broadcast decoder

312 switch 313 digital modulator

314 transmitter 316 controller

317 local band filter 318 local amplifier

319: voltage controlled oscillator 320: PLL circuit

321: intermediate frequency signal detector 322: first analog-to-digital converter

323: Image data storage memory

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

The present invention proposes a digital TV repeater and an error processing method which detects an error of a broadcast signal by itself in a digital TV repeater, and provides a subscriber with an error in the astigmatism area by providing a preset announcement to the subscribers when an error occurs. do.

To this end, the digital TV repeater according to the present invention detects an error of a broadcast signal using an intermediate frequency (IF) signal, and separately stores image data for transmitting instead of the distorted broadcast signal to subscribers in an astigmatism area.

3 is a block diagram of a digital TV repeater according to the present invention.

Referring to FIG. 3, the digital TV repeater according to the present invention receives a broadcast signal, demodulates it into an intermediate frequency (IF) signal, analyzes the demodulated intermediate frequency (IF) signal, and is already set when an error occurs. And a receiving end for outputting the video data to the transmitting end, and a transmitting end for modulating and amplifying the video data output from the receiving end and transmitting the same to the subscribers in the astigmatism region.

Here, the receiving end includes a band filter (BPF) 301 for filtering a radio frequency (RF) signal, a low noise amplifier (LNA) 302 for amplifying a radio frequency (RF) signal filtered by the band filter 301, A variable attenuator (ATT) 303 for adjusting the gain of the RF signal amplified by the low noise amplifier 302 and an RF signal output from the variable attenuator 303 are intermediate frequencies (IF). Mixer 304 for down-converting the frequency into a signal, an intermediate frequency (IF) filter 305 for filtering an intermediate frequency (IF) signal up-converted in the mixer 304, and the intermediate frequency (IF) filter. An intermediate frequency (IF) amplifier 306 that amplifies the intermediate frequency (IF) signal filtered at 305 and 44 MHz in the intermediate frequency (IF) signal output from the intermediate frequency (IF) amplifier 306 And a sour filter 307 which passes only 6 MHz in the middle, and the intermediate frequency IF output from the sour filter 307. ) A splitter 308 that separates the signal and outputs the two signals, and an intermediate frequency (IF) signal separated by the splitter 308, and receives a DC component according to the strength of the input intermediate frequency (IF) signal. An intermediate frequency (IF) signal detector 321 for outputting a signal and a first analog-to-digital converter (ADC) for converting a signal of a DC component output from the intermediate frequency (IF) signal detector 321 into a digital signal ( 322 and the digital signal output from the first analog-to-digital converter 322 (analyze the strength of the digital signal) to detect the occurrence of an error of the current broadcast signal when the strength of the digital signal falls below a set level. The controller 316 generates a control signal for outputting the image data stored in the image data storage memory 323 to the transmitter when an error occurs in the broadcast signal, and distorts it under the control of the controller 316. A video data storage memory 323 for outputting video data for transmission instead of a broadcast signal, and video data output from the video data storage memory 323 and the digital broadcast decoder 311 under the control of the controller 316. A switch 312 for outputting any one of the output broadcast signals, a digital demodulator 309 for converting an intermediate frequency (IF) signal output from the splitter 308 into a baseband signal, and a digital demodulator ( A second analog-to-digital converter (ADC) 310 for converting the baseband signal output from the step 309 into a digital signal, and the baseband signal output from the second analog-to-digital converter 310 for channel decoding. And a digital broadcast decoder 311 for outputting a broadcast signal in the form of a II transport stream. Here, the mixer 304 includes a local amplifier 318 and a local band filter (BPF) that amplify and filter the local oscillation frequency generated by the PLL circuit 320 and the voltage controlled oscillator 319 to provide the mixer 304 to the mixer 304. 317 is connected.

In addition, the transmitting end modulates the image data or the broadcast signal switched and output by the switch 312 to output an intermediate frequency (IF) signal, and the intermediate frequency (IF) output from the digital modulator 313. ) Is composed of a transmitter 314 that up-converts and transmits a signal to a frequency of a channel already set.

The operation of the digital TV repeater configured as described above is as follows.

First, a radio frequency (RF) signal received at the receiving antenna 300 is input to a band filter (BPF) 301. The band filter 301 outputs only a radio frequency (RF) signal of a required frequency band, and is amplified by a low noise amplifier (LNA) 302 because the radio frequency (RF) signal output from the band filter 301 is weak in intensity. . The gain of the radio frequency (RF) signal output from the low noise amplifier (LNA) 302 is adjusted by a variable attenuator 303 having an automatic gain control (AGC) function. The variable attenuator 303 is variable according to the reception strength detected by the digital demodulator 309 to prevent each element provided at the receiving end from being saturated and deteriorating reception quality when the received RF signal is strong. It serves to adjust the attenuation of the radio frequency (RF) signal.

The mixer 304 then multiplies the radio frequency (RF) signal output from the variable attenuator 303 by the local oscillation frequency provided by the local band filter 301 to multiply the radio frequency signal (RF) by 44 MHz. Frequency downconverts to a frequency (IF) signal. At this time, the PLL circuit 320 and the voltage controlled oscillator (VCO) 319 generate a local oscillation frequency from 517 MHz to 847 MHz and provide it to the mixer 304.

The intermediate frequency (IF) filter 305 then removes the unnecessary frequency band signal generated by the harmonic from the intermediate frequency (IF) signal generated by the mixer 304 and then the 44 MHz intermediate frequency (IF) signal, which is a required frequency band. Output only.

The intermediate frequency (IF) signal output from the intermediate frequency (IF) filter 305 is amplified by the intermediate frequency (IF) amplifier 306 and amplified by the intermediate frequency (IF) amplifier 306. Is filtered in a saw filter 307 with high selectivity.

At this time, the divider 308 separates the intermediate frequency (IF) signal filtered by the saw filter 307 and outputs one to the digital demodulator 309 and the other to the intermediate frequency (IF) signal detector 321. do.

Then, the digital demodulator 309 demodulates the intermediate frequency (IF) signal separated by the divider 308 into a baseband signal, and outputs the baseband signal. The baseband signal output from the digital demodulator 309 is a second analog-to-digital converter. At 310 it is converted to a digital signal. The digital broadcast decoder 311 channel-decodes the digital baseband signal output from the second analog-to-digital converter 310 and outputs the MPEG-II transport stream signal to the switch 312.

Meanwhile, the intermediate frequency (IF) signal detector 321 outputs a signal of a DC component according to the level of the intermediate frequency (IF) signal input through the divider 308. Then, the first analog-to-digital converter 322 converts the signal of the DC component output from the intermediate frequency (IF) signal detector 321 into a digital signal and outputs the digital signal to the controller 316.

The controller 316 analyzes the strength of the digital signal output from the first analog-to-digital converter 322 and determines that an error has occurred in the current broadcast signal when the set of digital signals falls below a set level. When an error occurs in the current broadcast signal according to the determination result, transmission of the current broadcast signal is stopped and a control signal is generated to the image data storage memory 323 and the switch 312. In addition, the controller 316 generates a warning message to an operation center (not shown) to enable the system operator to know that an error has occurred.

Then, the image data storage memory 323 outputs the image data already stored under the control of the controller 316, and the switch 312 selects the image data output from the image data storage memory 323 and uses the digital modulator. Output to (313). In this case, the video data output from the video data storage memory 323 is an MPEG-II transport stream signal.

As such, the controller 316 normally controls the switch 312 to transmit the received broadcast signal to the transmitting end, and when an error occurs in the receiving end or the digital broadcast transmitter and an error occurs in the broadcast signal, the image data storage memory ( The switch 312 is controlled to transmit the image data, which is already set at 323, to the transmitting end.

The digital modulator 313 then modulates and outputs image data in the form of an MPEG-II transport stream output from the switch 312 into an analog 44 MHz intermediate frequency (IF) signal, and the transmitter 314 outputs the digital modulator 313. After converting the intermediate frequency (IF) signal outputted from the channel frequency to the already set, and amplified and transmitted to the blind spot through the transmitting antenna.

Then, the following images are received and displayed to subscribers in the astigmatism area.

'Currently the broadcast is suspended due to the relay station.'

Accordingly, subscribers in the astigmatism area can reduce reception dissatisfaction with the digital TV broadcasting system by receiving an announcement that they are currently checking the repeater without watching the TV screen which is not received.

On the other hand, the system operator of the operation center (not shown) can take prompt measures because the system operator can detect the error occurrence of the current broadcast signal by looking at the message provided by the controller 316.

As described above, according to the digital TV repeater and the error processing method according to the present invention, an intermediate frequency (IF) signal is used to detect whether an error occurs in a broadcast signal, and when an error occurs, a subscriber is provided by transmitting a preset broadcast to the subscriber. This can reduce the complaints of the reception, and also the system operator can recognize the occurrence of the error of the broadcast signal and take a prompt action accordingly, thereby providing a digital broadcasting service of a certain quality.

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 examples, but should be defined by the claims.

Claims (4)

A filtering unit for receiving a radio frequency (RF) broadcast signal, a demodulation unit for demodulating the received broadcast signal into a baseband signal, and a modulation for modulating the baseband signal output from the demodulator into an intermediate frequency (IF) signal In the digital TV repeater consisting of a transmission unit for transmitting an intermediate frequency (IF) signal output from the modulator at a predetermined channel frequency, A memory for storing arbitrary image data, A switch for selecting one of the image data stored in the memory and the baseband signal output from the demodulator and outputting the selected one to the modulator; A signal detector which extracts the broadcast signal output from the filtering unit and outputs the direct current (DC) signal; An analog / digital converter for outputting the output DC signal as a digital signal; Analyzing the output digital signal to determine whether an error occurs in the received broadcast signal according to whether the intensity of the output digital signal is lower than the set level, and to transmit the image data stored in the memory when the error occurs And a controller for controlling the memory and the switch. The digital TV repeater of claim 1, further comprising a divider which separates the broadcast signal output from the filtering unit and outputs the signal to the signal detector or the demodulator. A first step of receiving a broadcast signal and outputting it as an intermediate frequency (IF) signal; A second step of extracting the output intermediate frequency (IF) signal and outputting it as a direct current (DC) signal; A third step of converting the output DC signal into a digital signal and outputting the digital signal; Analyzing the output digital signal to determine whether an error of the received broadcast signal occurs according to whether the intensity of the output digital signal falls below a set level; If an error occurs in the received broadcast signal according to the determination result, a fifth step of outputting already set video data to a transmitting end; And a sixth step of transmitting the output image data to guide broadcast. The method of claim 3, wherein the fifth step, Stopping transmission of a broadcast signal currently being broadcast under control of the controller; And outputting image data already stored in a memory to the transmitter in the form of an MPEG-II transport stream.