KR100774192B1 - Ground wave receiving apparatus and method for digital television - Google Patents

Abstract

The present invention relates to an apparatus and method for terrestrial wave reception of a digital broadcast receiver which improves a problem in that a DTV video signal is broken due to the effect of phase noise generated in a retransmission equipment of a wireline operator during retransmission of a DTV. The present invention provides a VSB receiver for receiving an image signal by maintaining an initial bandwidth at a default value; If the received image is broken, it is determined whether it is caused by phase noise, and as a result of the determination, if the image is broken by the phase noise, it characterized in that it comprises a control unit for correcting the error by setting the bandwidth wide. The default value is an initial design value that satisfies the ATSC recommendation standard, and takes into account both phase noise and impulse noise, and the controller sets a wide bandwidth of a phase loop filter when the image is broken due to the phase noise. . Therefore, in the region where phase noise does not occur in retransmission equipment, the initial default setting value is applied as it is, and when the image is broken by phase noise, it detects it and sets the bandwidth of the phase loop filter to widen the error. By correcting, it is possible to cope very effectively in case of both phase noise and impulse noise.

DTV, Retransmission, Phase, Noise, Impulse, Terrestrial, VSB, Bandwidth

Description

Terrestrial receiver and method for digital broadcasting receiver {GROUND WAVE RECEIVING APPARATUS AND METHOD FOR DIGITAL TELEVISION}

1 is a block diagram illustrating a terrestrial wave receiver of a digital broadcast receiver according to the prior art.

2 is a block diagram showing a terrestrial wave receiver of a digital broadcast receiver according to the present invention;

3 is a flowchart illustrating a terrestrial wave reception method of a digital broadcast receiver according to the present invention.

<Description of Symbols for Major Parts of Drawings>

100: RF signal processing unit 110: AV input detection unit

120: AV signal processing unit 130: DTV tuner

140: VSB receiving chip 150: display unit

160 control unit (CPU)

The present invention relates to a digital broadcasting receiver (DTV), and more particularly, to improve the problem that the DTV video signal is broken due to the influence of phase noise generated in the retransmission equipment of the wireline operator during the retransmission of the DTV. An apparatus and method for terrestrial wave reception in a digital broadcast receiver.

In general, in the digital broadcasting signal environment, there are two cases in which a DTV reception method using an outdoor antenna and an indoor antenna is directly received, and a DTV signal is received from cable SO and apartment public facilities. At this time, in case of receiving DTV signal from cable SO and apartment public hearing facility, it is a transmission system of DTV retransmission concept through signal processor.

The retransmission equipment applied to the transmission system of the DTV retransmission concept uses an SAW filter to down-convert the RF signal to an IF signal and then retransmits the analog processor system and the RF signal to the desired RF signal. It is divided into a digital processor system that modulates and generates TP data, and then modulates and retransmits it as an RF signal.

In the case of analog processor systems, SAW filtering must be done sharply in order to convert to IF signals, which improves the C / N characteristics. In general analog systems, C / N characteristics and local OSC Due to the characteristics, the C / N characteristics deteriorate, and phase noise is introduced into the source signal during the retransmission process.

Here, the phase noise is a phenomenon in which the phase of the oscillation signal is slightly pushed and distorted in the time-axis waveform so that the waveform appears to be distorted. Indicates if power is running down. Since the signal power floating outside the center frequency can be regarded as noise, it is classified as a kind of noise called phase noise.

Also, in the case of a digital processor system, if the timing between the demodulation and the modulation is out of time due to a data buffering problem, the buffer on the system becomes full and an error occurs in the contents. There is a problem that the video is broken.

1 is a block diagram illustrating a terrestrial wave receiving apparatus of a digital broadcast receiver according to the prior art. In general, a digital cable set-top box 10 and a DTV tuner 20 for receiving digital broadcasts and a VSB ( A VSB receiver 30 having a Vestigial Side Band (Chip) chip must be provided. The AV signal decoded by the set top box 10 is input through the AV terminal of the DTV tuner 20 to watch cable broadcasting. In this case, the input of the set-top box 10 is a cable signal conforming to the digital cable standard sent from the cable broadcasting station, the set-top box receives and processes it and outputs it to the digital broadcasting receiver serving as a display through the AV terminal.

On the other hand, in terms of phase noise according to the Korean cable broadcasting technology standard, VHF channel (-98dBc / Hz or less) and UHF channel (-95 dBc / Hz or less) are specified, and ATSC recommendation standard is- It is specified at 80dBc and a typical VSB receiver chip is designed at -75dBc with a 5dB margin to the default setting.

However, in the conventional terrestrial receiver and method of the digital broadcasting receiver, the phase noise is introduced at -75dBc or higher, which is higher than the Korea cable broadcasting technology standard and ATSC recommendation, for the design of the VSB receiver chip. By leaving the margin, there is a problem that a bad DTV reception occurs. In this case, this problem can be improved by changing the register value of the DTV receiver chip. However, in this case, the phase noise characteristics are improved while the impulse noise characteristics are deteriorated due to the opposite benefits. .

The present invention is to solve the above problems, the initial bandwidth when receiving the DTV video through retransmission keeps the default value and the bandwidth (Bandwidth) of the phase loop filter (Phase Loop Filter) only when the image is broken by the phase noise It is an object of the present invention to provide an apparatus and method for terrestrial wave reception of a digital broadcast receiver, which is set to have a wider range and to correct errors.

In order to achieve the above object, the terrestrial wave receiving apparatus of the digital broadcasting receiver according to the present invention comprises: a DTV image receiving apparatus through retransmission, comprising: a VSB receiving unit for receiving an image signal by maintaining an initial bandwidth at a default value; If the received image is broken, it is determined whether it is caused by phase noise, and as a result of the determination, if the image is broken by the phase noise, it characterized in that it comprises a control unit for correcting the error by setting the bandwidth wide.

The default value is an initial design value that satisfies the ATSC recommendation standard, and takes into account both phase noise and impulse noise, and the controller sets a wide bandwidth of a phase loop filter when the image is broken due to the phase noise. .

In addition, when the received image is broken, it is preferable to determine the phase tracking error by reading a phase tracking error in the VSB chip and comparing the values.

In addition, a terrestrial wave reception method of a digital broadcast receiver according to the present invention includes a method of receiving a DTV image through retransmission, the method comprising: receiving an image signal by maintaining an initial bandwidth at a default value; Determining whether the image is broken due to phase noise; As a result of the determination, when the image is broken by the phase noise, the step of setting the bandwidth wider to correct the error.

Therefore, the present invention improves the conventional method that does not correspond to the impulse noise when the initial value is changed, and basically maintains and sets the initial design value that satisfies the ATSC recommendation standard when receiving the channel, and the DTV image. If broken, read the phase tracking error in the VSB chip, check if it is caused by phase noise, and if the image is broken by phase noise, use the bandwidth of the phase loop filter. ) To make the error wider. In addition, when the bandwidth is set wide, as mentioned above, since it is affected by the impulse noise, when the phase noise is eliminated, it is returned to the initial register setting value.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

2 is a block diagram illustrating a terrestrial wave receiving apparatus of a digital broadcast receiver according to the present invention.

As shown, the present invention, in the DTV image receiving apparatus through retransmission, RF signal processing unit 100, AV input detection unit 110, AV signal processing unit 120, DTV tuner 130, VSB receiving chip ( 140, a display unit 150, and a controller (CPU) 160.

The RF input signal processing unit 100 demodulates analog and digital signals input through the RF input terminal, and the AV signal input detecting unit 110 detects the presence or absence of an AV signal input through the AV input terminal, and the AV signal processing unit 120. ) Processes audio and video signals inputted through the AV input terminal. The DTV tuner 130 processes the input terrestrial VSB signal (RF signal) and displays it on the display unit 150.

In addition, the VSB receiver 140 receives an image signal by keeping the initial bandwidth at a default value, and the controller 160 determines whether phase noise is caused by a phase noise when the received image is broken. If the image is broken by setting the bandwidth wide, correct the error.

The VSB signal is a digital terrestrial transmission standard signal, also referred to as a residual sideband (VSB) modulation method. This residual sideband (VSB) modulation is one of the modulation methods used to send digital broadcasts to terrestrial waves, and is mainly used in the United States. It is named because the carrier is located on the side of the frequency band. In multi-value VSB modulation method, 8-VSB and 16-VSB are converted to 8- or 16-stage by transmitting the amplitude of the signal to 3 or 4 bits. Means that. In the 8-VSB method, the transmitted signal is first converted into a set of signals by 3 bits and output as an 8 level signal having an amplitude value represented by 3 bits. Through this converter, the data sequence of 101 111 001 100 --- is amplitude-modulated by the 8-level (3-bit) pulse signal. The advantage of the residual sideband modulation is that there is no crosstalk between the orthogonal signals compared to the orthogonal modulation, which is strong in phase distortion of the transmission line or equipment. Orthogonal modulation requires a two-phase waveform equalization circuit of in-phase orthogonal components, but in a multi-value VSB, since it is a single carrier, the waveform equalization circuit is simplified to one system.

The default value of the present invention is an initial design value that satisfies the ATSC recommendation standard and is a value that considers phase noise and impulse noise together, and the controller 160 is a phase loop filter when an image is broken by the phase noise. Set a wider bandwidth.

In addition, when the received image is broken, it is preferable to determine the phase tracking error by reading a phase tracking error in the VSB chip and comparing the values.

3 is a flowchart illustrating a terrestrial wave reception method of a digital broadcast receiver according to the present invention.

As shown, the terrestrial wave reception method of the digital broadcast receiver according to the present invention comprises the steps of: receiving a video signal by maintaining an initial bandwidth at a default value in a DTV image reception method through retransmission; Determining whether the image is broken due to phase noise (S102 to S103); As a result of the determination, if the image is broken due to the phase noise, the bandwidth is set to be wider to correct the error (S104 to S107).

In this case, the default value is an initial design value that satisfies the ATSC recommendation standard and takes into account both phase noise and impulse noise. When the image is broken by the phase noise, a bandwidth of a phase loop filter is set to be wide.

In addition, when the received image is broken, it is preferable to determine the phase tracking error by reading a phase tracking error in the VSB chip and comparing the values.

Referring to the operation of the present invention configured as described in more detail as follows.

First, the RF input signal processing unit 100 demodulates analog and digital signals input through the RF input terminal, and the AV signal input detection unit 110 detects the presence or absence of an AV signal input through the AV input terminal, and the AV signal processing unit. 120 processes audio and video signals input through the AV input terminal.

In addition, the DTV tuner 130 processes the input terrestrial VSB signal (RF signal) and displays it on the display unit 150.

In this state, the VSB receiver 140 receives an image signal by keeping the initial bandwidth at a default value (S101).

In other words, the default value is an initial design value that satisfies the ATSC recommendation standard, and is a value considering phase noise and impulse noise together. Accordingly, the present invention applies an initial default setting value in an area where phase noise does not occur in retransmission equipment, and detects when an image is broken by phase noise. Respond by changing the settings.

Thereafter, the controller 160 determines whether the received image is due to phase noise (S120). In this case, when the received image is broken, the determination is made by reading a phase tracking error in the VSB chip and comparing the values to determine whether the image is due to phase noise.

As a result of the determination, when the image is broken due to the phase noise, the bandwidth is set wide to correct the error (S103 to S104). In this case, when the image is broken by the phase noise, the controller 160 may set a bandwidth of a phase loop filter (not shown) to be wider.

Thereafter, if the DTV image is continuously broken, the DTV is received with a value set as a basic design value, and if the DTV image is not broken, the DTV is received with a value changed to a VSB chip setting corresponding to the phase noise (S105 ~). S107).

Therefore, the present invention sets the initial default value in the laboratory environment so that the initial design setting value satisfies the phase noise and the impulse noise of the ATSC recommendation standard, and the DTV image cracking phenomenon which may be caused by additional noise to correspond to the field environment In this case, the register of the VSB receiving chip is read, and if it is caused by a phase noise error, the margin due to impulse noise does not occur even if a little loss. This is to prevent such a problem in advance if the setting value is changed to ensure only margin for phase noise by default from the beginning, it may be a problem in the environment with impulse noise.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

As described above, according to the terrestrial wave receiving apparatus and method of the digital broadcasting receiver according to the present invention, the initial default setting is applied as it is in the region where the phase noise generated in the retransmission equipment does not occur, and the image is captured by the phase noise. When broken, it is detected and the bandwidth of the phase loop filter is set to be wide to correct the error, so that both phase noise and impulse noise can be effectively coped with.

Claims (8)

In the apparatus for receiving DTV video through retransmission, A VSB receiver configured to receive an image signal by maintaining an initial bandwidth at a default value considering both phase noise and impulse noise as an initial design value satisfying an ATSC recommendation standard; And a control unit for determining whether the received image is caused by phase noise, and if the image is broken due to the phase noise, correcting an error by setting a wide bandwidth of the received image. Terrestrial receiver. delete The method of claim 1, The control unit, The terrestrial wave receiver of the digital broadcasting receiver, wherein the bandwidth of the phase loop filter is set to be wide when the image is broken by the phase noise. The method of claim 1, And a phase tracking error in a VSB chip when the received image is broken to determine whether the image is due to phase noise. In the method of receiving a DTV video through retransmission, Receiving an image signal by maintaining an initial bandwidth at a default value considering both phase noise and impulse noise as an initial design value that satisfies the ATSC recommendation standard; Determining whether the image is broken due to phase noise; And if the image is broken due to the phase noise as a result of the determination, correcting the error by setting a wide bandwidth thereof. delete The method of claim 5, When the image is broken by the phase noise, the terrestrial wave reception method of the digital broadcast receiver, characterized in that for setting a wide bandwidth of the phase loop filter. The method of claim 5, If the received image is broken, it is determined whether or not it is caused by phase noise by reading the phase tracking error in the VSB chip and comparing the values.

Images