JP2006217008A - DIGITAL CABLE BROADCAST RECEIVER COMPATIBLE WITH US OpenCable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of clarifying a receiving status (Status of FAT) of a receiver in the case of installing the receiver to a user's house whereby an S/N close to a reception limit value of a front end part of the receiver is displayed and it is correctly discriminated as to whether the front end or a back end part is a cause to a fault when an image cannot be correctly displayed. <P>SOLUTION: The digital cable broadcast receiver compatible with the US OpenCable specifications adds an item of error indicator converted from a bit error rate in MPEG transport packets and displaying the presence of a TS error to items of the receiving status (Status of FAT) of a cable in a picture (OPENCABLE HOST DEVICE DIAGNOSTICS) for displaying a status of channels. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a receiver for digital cable broadcasting and a television set corresponding to the OpenCable standard / specification in the United States.

  In the US cable industry, the OpenCable standard was established in 1997 for the purpose of revitalizing the cable industry by the proposal of a group that determines the standard for North American cable called Cable Lab.

  One of the OpenCable standards is OpenCableHostDevice1.0CoreFunctionalRequirement related to a receiver that receives broadcasts corresponding to OpenCable. Among the specifications, there is a specification regarding the contents for displaying the cable reception status (STATUS) of the receiver called OPENCABLE HOST DEVICE DIAGNOSTICS.

  Among the STAUS items, there is an item indicating the status of IN_BAND broadcasting called Status of FAT.

  The conventional Status of FAT has been standardized to display the modulation method (analog, 64QAM, 256QAM), carrier wave lock state, S / N ratio, and input level (dBmV) (page 53 of Non-Patent Document 1). Described in).

  When a cable broadcasting receiver is installed in the customer's house, the status of the cable broadcasting to be distributed is determined by looking at these statuses.

Next, the configuration of a conventional receiver is shown in FIG. Selects a desired channel from the IN_BAND band QAM modulation signal sent from the cable company, QAM demodulation, error correction, decodes the transport stream signal, and OUT_OF_BAND band QPSK modulation sent from the cable company Selects a desired frequency from the signal, performs QPSK demodulation, error correction, decodes billing information, user information, channel information, etc., and restores MPEG images and digital audio from the transport stream signal , A back-end unit 402 that converts analog video and analog audio and outputs the same to the outside, a system control unit 108 that controls the entire receiver system, and a graphic unit 109 that creates a program guide and a graphic screen. .
OC-SP-HOST1.0-CFR-C010040629

  The problems to be solved are the conventional status of FAT items such as modulation method, carrier wave lock state, S / N ratio, and input level information. The reception status cannot be clearly expressed.

  In particular, the S / N ratio value has an error of ± 2 dB, and when the S / N value is close to the reception limit value of the front end of the receiver, the front end can receive without error in the transmission path. There is a problem that it is impossible to judge whether or not it is.

  For example, when receiving the 256QAM scheme, if the reception limit S / N ratio in the error-free front-end part is 30 dB, the S / N ratio value of Status of FAT is displayed as 31 dB. When the image is not correctly displayed, there is a problem that it is difficult to determine whether the cause is the front end part or the back end part.

  The present invention converts a bit error in an MPEG transport packet and displays the presence or absence of a TS error in the item of the cable reception state (Status of FAT) on the screen (OPENENABLE HOST DEVICE DIAGNOSTICS) for displaying the channel state. An error indicator is added and displayed. Also, the present invention is characterized in that an item of bit error rate calculated by the front end unit is added to the item of Status of FAT and displayed.

  The US OpenCable compatible digital cable broadcasting receiver of the present invention displays an S / N value close to the reception limit value of the front end portion of the receiver, and if the image is not correctly displayed, whether the front end portion is the cause, There is an advantage that it is possible to correctly determine whether the back end is the cause and to clarify the reception state of the receiver when the receiver is installed at the user's house.

(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of a US OpenCable compatible digital cable broadcasting receiver according to a first embodiment of the present invention.

  The signal input unit 101 to which both the FAT (FORWARD APPLICATION TRANSPORT CHANNEL) signal and the FDC (FORWARD DATA CHANNEL) signal from the cable company are input, and the frequency of the channel selected from the FAT signal and the local signal are mixed and specified frequency The IF tuner signal 102 that converts the frequency to an IF signal, removes adjacent channels, and outputs an appropriate signal for the QAM demodulator to operate correctly, the QAM demodulator 103 that demodulates the QAM modulated signal, and the transmission An error correction unit 104 that corrects an error in the path and outputs a transport stream signal (TS signal); calculates an error amount of the transport packet from the transport stream output from the error correction unit; TS error amount calculation unit 1001 for determining the presence or absence of packet error, MPEG decoding unit and audio decoding unit 105 that performs MPEG decoding and audio decoding from a transport stream signal to generate a digital image signal and a digital audio signal, and a digital image signal From the VideoDAC unit 106 that converts to an analog image signal, the AudioDAC unit 107 that converts a digital audio signal to an analog audio signal, the system control unit 108, the graphic unit 109 that creates a screen indicating the reception status of the channel, and the MPEG decoding unit A screen mixing unit 110 that mixes the output digital image signal and a screen indicating the reception state of the channel output from the graphic unit 109, an analog image signal output unit 111 that outputs an analog image signal, and an analog audio signal An analog audio signal output unit 112 to output, an external control signal input terminal 113 to which system control information is input from a remote controller, an external button, or the like, and an FDC signal set to a POD (Point of Deployment) unit. Selects an existing frequency, converts the frequency to an IF signal, removes an adjacent channel, and demodulates a QPSK-modulated signal, and an FDC tuner unit 114 that outputs an appropriate signal for proper operation of the QPSK demodulator The QPSK demodulator 115 and the POD unit 116 that receives the frequency of the FDC signal sent from the cable company and the information (channel arrangement information, billing information, customer information) included in the FDC signal. .

  The operation will be described below with reference to FIG. First, a FAT signal and an FDC signal are transmitted from the cable company to the signal input unit 101. The signal from the signal input unit 101 is supplied to the FAT tuner unit 102 and the FDC tuner unit 114.

  Next, the frequency channel information of the FDC signal designated by the POD unit 116 is transmitted to the system control unit 108, and the system control unit 108 instructs the FDC tuner unit 114 to select the frequency. The FDC tuner unit 114 selects a frequency at which the FDC signal transmitted from the system control unit 108 exists, converts the frequency to an IF signal, removes an adjacent channel, and performs an appropriate operation so that the QPSK demodulation unit operates correctly. Output a signal. Thereafter, the data is transmitted to the subsequent QPSK demodulator 115, and the QPSK demodulator 115 performs QPSK demodulation.

  Thereafter, channel arrangement information, billing information, and the like from the cable company are delivered to the POD unit 116, and the system control unit 108 manages these information.

  After that, when the channel desired by the customer is selected by the remote controller or the external button, the information is inputted from the external control signal terminal 113 and sent to the system control unit 108. The system control unit 108 sends the information to the FAT tuner unit 102. Communicate information. The FAT tuner unit 102 selects the channel selection frequency of the channel, converts the frequency into an IF signal of a specified frequency, removes the adjacent channel, and outputs an appropriate signal for the subsequent QAM demodulation unit 103 to operate correctly. . The QAM demodulator 103 QAM demodulates the QAM modulated signal and passes it to the error correction unit 104 at the subsequent stage. The error correction unit 104 corrects an error in the transmission path and outputs a transport stream signal including error information (see FIG. 3).

  The transport stream is composed of 188-byte fixed-length transport packets. The transport packet includes a synchronization byte for detecting the head of the transport packet, an error indication (error indicator) indicating the presence or absence of a bit error in the packet, and a new PES packet including the payload of the transport packet. Unit start display indicating that the packet starts, transport packet priority indicating the importance of the packet, PID (Packet Identification) indicating the attribute of the individual stream of the packet, whether the payload of this packet is scrambled, and the type Scramble control, adaptation field control indicating the presence / absence of an adaptation field and the presence / absence of a payload in this packet, and detecting whether a packet with the same PID was partially discarded Cyclic counter which is because of the information is constituted by a payload is adaptation field, information including additional information regarding the individual stream.

  The present invention uses an error indication (error indicator) in the transport packet component.

  The transport stream output from the error correction unit 104 is subjected to MPEG decoding and audio decoding in the MPEG decoding unit + audio decoding unit 105, and a digital image signal and a digital audio signal are generated. Thereafter, the digital image signal is converted into an analog image signal by the VideoDAC unit 106 and output from the analog image signal output terminal 111. The digital audio signal is converted into an analog audio signal by the AudioDAC unit 107 and output from the analog audio output terminal 112.

  On the other hand, the transport stream output from the error correction unit 104 is input to the TS error amount calculation unit 1001.

  TS error amount calculation section 1001 measures the number of error indications (error indicators) from n transport packets. If there are m (1 ≦ m ≦ n) errors among n transport packets, it is determined that there are m / n errors (TS_Error: m / n), and if there are no errors, It is determined that there is no error (TS_Error: No_Error). Then, information regarding the TS error amount is output to the system control unit 108.

  In the graphic unit 109, a screen (OPEN CABLE HOST DEVICE DIAGNOSTICS) displaying the channel status shown in FIG. 2 from the FAT information, FDC information, transport packet error information, etc. sent from the system control unit 108. Create Only when a control signal for displaying a screen for displaying the channel state is received from the external signal input terminal 113, the screen mixing unit 110 mixes the reception screen and the screen indicating the channel reception state, and the VideoDAC unit 106. And output to the analog image output terminal 111.

  From the above, in the screen shown in FIG. 2, when the S / N value close to the reception limit value of the front end portion of the receiver is displayed and the image is not correctly displayed, and there is a TS error, the front end portion is It can be determined that this is the cause, and if there is no TS error, it can be determined that the back end is the cause.

(Embodiment 2)
FIG. 4 is a block diagram showing the configuration of a US OpenCable compatible digital cable broadcasting receiver showing the first embodiment of the present invention.

  The signal input unit 101 to which both the FAT (FORWARD APPLICATION TRANSPORT CHANNEL) signal and the FDC (FORWARD DATA CHANNEL) signal from the cable company are input, and the frequency of the channel selected from the FAT signal and the local signal are mixed and specified frequency The IF tuner signal 102 that converts the frequency to an IF signal, removes adjacent channels, and outputs an appropriate signal for the QAM demodulator to operate correctly, the QAM demodulator 103 that demodulates the QAM modulated signal, and the transmission An error correction unit 104 that corrects an error in the path and outputs a transport stream signal (TS signal); a bit error rate calculation unit 1002 that converts a bit error rate using data before and after the error correction unit 104; The transport strike MPEG decoding and audio decoding unit 105 that generates a digital image signal and a digital audio signal by MPEG decoding and audio decoding from the stream signal, a VideoDAC unit 106 that converts the digital image signal into an analog image signal, and an analog audio signal from the digital audio signal The audio DAC unit 107 that converts the signal, the system control unit 108, the graphic unit 109 that creates a screen indicating the reception state of the channel, the digital image signal output from the MPEG decoding unit, and the channel output from the graphic unit 109 A screen mixing unit 110 that mixes screens indicating reception states, an analog image signal output unit 111 that outputs an analog image signal, an analog audio signal output unit 112 that outputs an analog audio signal, a remote control, an external button, and the like. The frequency at which the FDC signal set in the POD (Point of Deployment) unit exists is selected from the external control signal input terminal 113 to which the program control information is input and the FDC signal, and the frequency is converted into an IF signal. The FDC tuner 114 that outputs an appropriate signal for the QPSK demodulator to operate correctly, the QPSK demodulator 115 that demodulates the QPSK modulated signal, and the FDC signal sent from the cable company The POD unit 116 receives the frequency and information (channel arrangement information, billing information, customer information) included in the FDC signal.

  The operation will be described below with reference to FIG. First, a FAT signal and an FDC signal are transmitted from the cable company to the signal input unit 101. The signal from the signal input unit 101 is supplied to the FAT tuner unit 102 and the FDC tuner unit 114.

  Next, the frequency channel information of the FDC signal designated by the POD unit 116 is transmitted to the system control unit 108, and the system control unit 108 instructs the FDC tuner unit 114 to select the frequency. The FDC tuner unit 114 selects a frequency at which the FDC signal transmitted from the system control unit 108 exists, converts the frequency to an IF signal, removes an adjacent channel, and performs an appropriate operation so that the QPSK demodulation unit operates correctly. Output a signal. Thereafter, the data is transmitted to the subsequent QPSK demodulator 115, and the QPSK demodulator 115 performs QPSK demodulation.

  Thereafter, channel arrangement information, billing information, and the like from the cable company are delivered to the POD unit 116, and the system control unit 108 manages these information.

  After that, when the channel desired by the customer is selected by the remote controller or the external button, the information is inputted from the external control signal terminal 113 and sent to the system control unit 108. The system control unit 108 sends the information to the FAT tuner unit 102. Communicate information. The FAT tuner unit 102 selects the channel selection frequency of the channel, converts the frequency into an IF signal of a specified frequency, removes the adjacent channel, and outputs an appropriate signal for the subsequent QAM demodulation unit 103 to operate correctly. . The QAM demodulator 103 QAM demodulates the QAM modulated signal and passes it to the error correction unit 104 at the subsequent stage.

  The error correction unit 104 corrects an error in the transmission path and outputs a transport stream signal including error information (see FIG. 3).

  The bit error rate calculation unit 1002 converts the bit error rate using data before and after the error correction unit 104 and outputs the converted bit error rate to the system control unit 108.

  The transport stream output from the error correction unit 104 is subjected to MPEG decoding and audio decoding in the MPEG decoding unit + audio decoding unit 105, and a digital image signal and a digital audio signal are generated. Thereafter, the digital image signal is converted into an analog image signal by the VideoDAC unit 106 and output from the analog image signal output terminal 111. The digital audio signal is converted into an analog audio signal by the AudioDAC unit 107 and output from the analog audio output terminal 112.

  The graphic unit 109 creates a screen (OPEN CABLE HOST DEVICE DIAGNOSTICS) for displaying the channel state shown in FIG. 5 from the FAT information, FDC information, bit error rate information, etc. sent from the system control unit 108. To do. Only when a control signal for displaying a screen for displaying the channel state is received from the external signal input terminal 113, the screen mixing unit 110 mixes the reception screen and the screen indicating the channel reception state, and the VideoDAC unit 106. And output to the analog image output terminal 111.

  From the above, in the screen shown in FIG. 5, when the S / N value close to the reception limit value of the front end unit of the receiver is displayed and the image is not correctly displayed, and the bit error rate is not zero, the front end If the bit error rate is zero, it can be determined that the back-end part is the cause.

  The present invention can be applied not only to a digital cable broadcast receiver compatible with US OpenCable but also to a DVD recorder having a digital cable broadcast reception function.

The figure which showed the structure of the receiver in Embodiment 1 of this invention The figure which showed an example of the screen display in Embodiment 1 of this invention Diagram showing the structure of the transport stream The figure which showed the structure of the receiver in Embodiment 2 of this invention The figure which showed an example of the screen display in Embodiment 2 of this invention Diagram showing the configuration of a conventional receiver

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Signal input part 102 FAT tuner part 103 QAM demodulation part 104 Error correction part 105 MPEG decoding part + audio | voice decoding part 106 VideoDAC part 107 AudioDAC part 108 System control part 109 Graphic part 110 Screen mixing part 111 Analog image signal output terminal 112 Analog audio | voice Signal output terminal 113 External control signal input terminal 114 FDC tuner section 115 QPSK demodulator section 116 POD section 401 Front end section 402 Back end section

Claims (7)

A broadcast receiver that receives a broadcast signal, selects, demodulates, and decodes, and displays on the screen whether there is an error in the transport stream demodulated from the broadcast signal, the amount of error, or the error rate. A broadcast receiver. A tuner unit that receives and selects a modulated broadcast signal, a demodulation unit that demodulates the modulated broadcast signal input from the tuner unit, and corrects an error in the demodulated broadcast signal and outputs a transport stream An error correction unit; and a front end unit including an error amount calculation unit that determines whether or not there is an error in the transport stream output from the error correction unit;
A broadcast receiver comprising a decoding unit that decodes the transport stream output from the error correction unit, and a back-end unit that includes a DAC unit that converts the decoded digital signal into an analog signal,
A broadcast receiver, comprising: a graphic unit that displays on a screen whether or not there is an error in the transport stream determined by the error amount calculation unit. The broadcast reception according to claim 2, wherein the determination of the presence or absence of an error by the error amount calculation unit is performed with reference to an error display (error indicator) included in each transport packet of the transport stream. Machine. A tuner unit that receives and selects a modulated broadcast signal, a demodulation unit that demodulates the modulated broadcast signal input from the tuner unit, and corrects an error in the demodulated broadcast signal and outputs a transport stream An error correction unit; and a front-end unit including an error amount calculation unit that calculates an error amount of the transport stream output from the error correction unit;
A broadcast receiver comprising a decoding unit that decodes the transport stream output from the error correction unit, and a back-end unit that includes a DAC unit that converts the decoded digital signal into an analog signal,
A broadcast receiver, comprising: a graphic unit for displaying an error amount of a transport stream determined by the error amount calculation unit on a screen. The error amount calculation by the error amount calculation unit is performed by aggregating error indications (error indicators) included in a plurality of transport packets constituting a transport stream. Broadcast receiver. A tuner unit that receives and selects a modulated broadcast signal, a demodulation unit that demodulates the modulated broadcast signal input from the tuner unit, and corrects an error in the demodulated broadcast signal and outputs a transport stream An error correction unit, and a front end unit including an error amount calculation unit for calculating an error rate of the transport stream output from the error correction unit;
A broadcast receiver comprising a decoding unit that decodes the transport stream output from the error correction unit, and a back-end unit that includes a DAC unit that converts the decoded digital signal into an analog signal,
A broadcast receiver, comprising: a graphic unit for displaying an error rate of a transport stream determined by the error amount calculation unit on a screen. The error rate calculation by the error amount calculation unit is calculated from a total of error indications (error indicators) included in a plurality of transport packets constituting a transport stream. Broadcast receiver.

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