JP2005167890A - Terrestrial wave digital broadcast receiver and terrestrial wave digital broadcast reception method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terrestrial wave digital broadcast receiver and a terrestrial wave digital broadcast reception method in which a circuit scale is reduced, a component cost is reduced and terrestrial wave digital broadcast can be received with high-definition picture quality. <P>SOLUTION: The terrestrial wave digital broadcast receiver is provided with antennas 11 and 12, tuners 13 and 14, and OFDM demodulation sections 15 and 16 corresponding to the number of monitors. When viewing the same contents on the plurality of monitors or when viewing contents on only one monitor, TSs outputted from a plurality of the OFDM demodulation sections 15 and 16 are composed of a diversity composition section 17. When viewing different contents on the plurality of monitors, TSs outputted from the plurality of OFDM demodulation sections 15 and 16 are distributed by the diversity composition section 17 and outputted to the corresponding monitors. Therefore, only by providing one set of circuits for a diversity composition, different contents can be projected on the plurality of monitors, and high-definition image quality contents can be outputted to one monitor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a terrestrial digital broadcast receiver and a terrestrial digital broadcast receiving method having a function of receiving two or more different terrestrial digital broadcasts in parallel.

  In Japan, terrestrial television broadcasting is being digitized. In 2011, digital terrestrial broadcasting will be implemented nationwide, and analog waves will be stopped. In terrestrial digital broadcasting, one channel is divided into 13 segments, and the 13 segments are composed of a maximum of 3 layers. Hierarchy is called a layer that requires the lowest C / N ratio to receive due to the high C / N ratio (Carrier to Noise ratio) that the layer can receive. The hierarchy, the hierarchy requiring the next highest C / N ratio is called the middle hierarchy, and the hierarchy requiring the lowest C / N ratio is called the weak hierarchy. In terrestrial digital broadcasting, different modulation schemes can be set for each segment, which makes it possible to transmit a plurality of programs with different bit rates and error tolerances within the same band. Therefore, a service for fixed reception and a service for mobile reception and mobile reception can be provided simultaneously.

  Therefore, in terrestrial digital broadcasting, OFDM (Orthogonal Frequency Division Multiplexing), which is one of frequency division multiplexing schemes resistant to multipath interference, is employed. In OFDM, a plurality of narrow-band carriers are arranged on the frequency axis, and data is distributed to each carrier for transmission. As a result, even if the waveform of a part of the carrier wave is disturbed due to multipath interference at the time of mobile reception, an error occurs in the data transmitted using that frequency, and correction can be made with data from another carrier wave.

  In addition, in order to realize high-definition image quality (for example, HDTV) reception by home-use television receivers, in terrestrial digital broadcasting, 12 segments out of 13 segments are used for reception of high-definition image quality. A modulation scheme such as 64-value QAM capable of transmitting data is employed. On the other hand, for receivers that can only be equipped with small antennas such as mobile receivers and portable receivers, broadcast with simple image quality to achieve stable reception, using one of 13 segments, A modulation method such as QPSK is adopted. Here, when receiving using 12 segments, a high C / N ratio of a weak layer is required, and when receiving using 1 segment, a low C / N ratio of a strong layer is required. To do.

  However, even a receiver such as a mobile receiver or a portable receiver can receive high-definition-quality digital terrestrial broadcast content using 12-segment broadcasting by using diversity reception technology. FIG. 5 is a diagram showing a configuration example of a conventional terrestrial digital broadcast receiver adopting diversity technology. In FIG. 5, 35 is a first antenna, and 36 is a second antenna. The first antenna 35 and the second antenna 36 receive radio waves of terrestrial digital broadcasting.

  Reference numeral 37 denotes a first tuner which is connected to the first antenna 35 and selectively extracts a signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast radio wave received by the first antenna 35. And output. Reference numeral 38 denotes a second tuner which is connected to the second antenna 36 and selectively receives a signal having a reception frequency matching a desired channel from the radio wave of the terrestrial digital broadcast received by the second antenna 36. Extract to and output.

  Reference numeral 39 denotes a first OFDM demodulator, which obtains a transport stream (hereinafter referred to as TS) by OFDM demodulating the signal received by the first tuner 37. Reference numeral 40 denotes a second OFDM demodulator, which obtains TS by OFDM demodulating the signal received by the second tuner 38. Reference numeral 41 denotes a diversity combining unit that combines a phase shifter 41 a that controls the phase of the TS input from the first OFDM demodulator 39, and the TS that is controlled by the phase and the TS that is input from the second OFDM demodulator 40. And a synthesizer 41b.

  An error correction unit 42 is used to correct errors that occur during transmission. Demultiplexer unit 43 separates the multiplexed TS and outputs a video stream and an audio stream. Here, the multiplexed TS may include an information stream for data broadcasting in addition to the video stream and the audio stream. An audio decoder unit 44 decodes the input audio stream and outputs it as audio. A video decoder 45 decodes the input video stream and outputs it as video.

  A control unit 46 determines a channel received by the first tuner 37 and the second tuner 38 based on a control signal input by an operation of a remote controller (not shown) provided outside, and this channel. Set the reception frequency that matches. The control unit 46 also receives information such as a reception state from the first tuner 37 and the second tuner 38 and outputs the information to the outside. Further, the control unit 46 also performs a process of selecting a hierarchy received by the first OFDM demodulator 39 and the second OFDM demodulator 40. Here, when receiving using one segment, the strong layer is selected as the receiving layer, and when receiving using 12 segments, the weak layer is selected as the receiving layer.

  As described above, the first antenna 35, the second antenna 36, the first tuner 37, the second tuner 38, the first OFDM demodulator 39, and the second OFDM demodulator 40 are provided, and the first OFDM Diversity combining of the TS output from the demodulator 39 and the second OFDM demodulator 40 by the diversity combiner 41 improves reception performance and allows reception of high-definition image quality digital terrestrial broadcast content. It becomes possible.

  Further, in a vehicle-mounted monitor or the like, a rear entertainment system is known that includes a rear monitor that projects an image on the rear seat in addition to a front monitor that projects an image on the front seat. Such a rear entertainment system is generally configured as shown in FIG.

  In FIG. 7, reference numeral 1 denotes a terrestrial digital broadcast receiver which receives terrestrial digital broadcast content and outputs front and rear video and audio. Reference numeral 2 denotes a navigation device which reads out map data in the vicinity of the current position of the vehicle from the recording medium and displays it on the screen, displays a vehicle position mark indicating the position of the vehicle superimposed on a predetermined position on the screen, and displays the desired data. It is equipped with a route guidance function that makes it possible to travel easily without making a mistake on the road toward the destination. The navigation device 2 outputs display contents and voice guidance by video and voice. Reference numeral 3 denotes a DVD playback device, which outputs video and audio recorded on a DVD video or the like.

  Reference numeral 4 denotes an interface box, which inputs video output and audio output from the terrestrial digital broadcast receiver 1, navigation device 2 and DVD playback device 3 described above, and outputs any video and audio according to user selection or the like. . Reference numeral 5 denotes a front monitor, which receives the front video and audio output from the interface box 4, displays the video, and outputs the audio. Reference numeral 6 denotes a rear monitor, which inputs the rear video and audio output from the interface box 4, displays the video, and outputs the audio. Here, the front monitor 5 and the rear monitor 6 have a source selection unit (not shown) for selecting any video and audio from the terrestrial digital broadcast receiver 1, the navigation device 2, the DVD playback device 3, and the like. Is provided.

  A terrestrial digital broadcast receiver applied to such a rear entertainment system is generally configured as shown in FIG. The terrestrial digital broadcast receiver shown in FIG. 6 receives terrestrial digital broadcasts from the front monitor 5 and the rear monitor 6 and outputs video and audio. In FIG. 6, 51 is the first antenna, 52 is the second antenna, 53 is the third antenna, 54 is the fourth antenna, and the first antenna 51 and the second antenna 52 are for the front monitor 5. The third antenna 53 and the fourth antenna 54 are used for reception for the rear monitor 6.

  Reference numeral 55 denotes a first tuner which is connected to the first antenna 51 and selectively extracts a signal having a reception frequency matching a desired channel from the terrestrial digital broadcast radio wave received by the first antenna 51. And output. Reference numeral 56 denotes a second tuner which is connected to the second antenna 52 and selectively receives a signal having a reception frequency matching a desired channel from the radio wave of the terrestrial digital broadcast received by the second antenna 52. Extract to and output. Reference numeral 57 denotes a third tuner, which is connected to the third antenna 53, and selectively receives a signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast radio wave received by the third antenna 53. Extract to and output. Further, reference numeral 58 denotes a fourth tuner which is connected to the fourth antenna 54 and selects a signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast wave received by the fourth antenna 54. Extracted and output.

  Reference numeral 59 denotes a first OFDM demodulator, which OFDM demodulates the signal received by the first tuner 55 to obtain a TS. Reference numeral 60 denotes a second OFDM demodulator, which OFDM demodulates the signal received by the second tuner 56 to obtain a TS. Reference numeral 61 denotes a third OFDM demodulator, which OFDM demodulates the signal received by the third tuner 57 to obtain a TS. Furthermore, reference numeral 62 denotes a fourth OFDM demodulator, which OFDM demodulates the signal received by the fourth tuner 58 to obtain a TS.

  Reference numeral 63 denotes a first diversity combiner, a phase shifter 63a for controlling the phase of the TS input from the first OFDM demodulator 59, a TS whose phase is controlled, and a TS input from the second OFDM demodulator 60. And a synthesizer 63b. Reference numeral 64 denotes a second diversity combiner, a phase shifter 64 a that controls the phase of the TS input from the third OFDM demodulator 61, and a phase-controlled TS and input from the fourth OFDM demodulator 62. And a synthesizer 64b for synthesizing the TS.

  Reference numeral 65 denotes a first error correction unit for correcting an error occurring during transmission with respect to signals received by the first tuner 55 and the second tuner 56. Reference numeral 66 denotes a second error correction unit for correcting an error generated during transmission with respect to signals received by the third tuner 57 and the fourth tuner 58.

  Reference numeral 67 denotes a demultiplexer unit that separates the TS input from the first error correction unit 65 and outputs the first video stream and the first audio stream, and the TS input from the second error correction unit 66. And the second video stream and the second audio stream are output. Reference numeral 68 denotes a first audio decoder, which decodes the input first audio stream and outputs it as front audio. Reference numeral 69 denotes a first video decoder, which decodes the input first video stream and outputs it as a front video. Reference numeral 70 denotes a second audio decoder, which decodes the input second audio stream and outputs it as rear audio. Reference numeral 71 denotes a second video decoder, which decodes the input second video stream and outputs it as a rear video.

  Reference numeral 72 denotes a control unit, which sets channels to be received by the first tuner 55 to the fourth tuner 58 according to a control signal input by an operation of a remote controller or the like (not shown) provided outside. In addition, the control unit 72 receives information such as the reception state from the first tuner 55 to the fourth tuner 58 and outputs the information to the outside. Further, the control unit 72 selects the reception hierarchy of the first OFDM demodulation unit 59 to the fourth OFDM demodulation unit 62.

  When a certain channel is selected on the front monitor 5, the control unit 72 sets the first tuner 55 and the second tuner 56 to the selected channel. In the first tuner 55 and the second tuner 56, the reception frequency matching the selected channel is set by the control signal from the control unit 72. In addition, the control unit 72 sets the reception layers of the first OFDM demodulation unit 59 and the second OFDM demodulation unit 60 to the same layer (for example, a 12-segment weak layer). Then, the TS output from the first OFDM demodulator 59 and the second OFDM demodulator 60 is diversity-combined by the first diversity combiner 63, so that the high-definition image content of the terrestrial digital broadcasting is front-mounted. It can be viewed on the monitor 5.

  On the other hand, when a certain channel is selected on the rear monitor 6, the control unit 72 sets the third tuner 57 and the fourth tuner 58 to the selected channel. In the third tuner 57 and the fourth tuner 58, the reception frequency matching the selected channel is set by the control signal from the control unit 72. In addition, the control unit 72 sets the reception layers of the third OFDM demodulation unit 61 and the fourth OFDM demodulation unit 62 to the same layer (for example, a 12-segment weak layer). Then, the TS output from the third OFDM demodulator 61 and the fourth OFDM demodulator 62 is diversity-combined by the second diversity combiner 64, so that it differs from the content viewed on the front monitor 5. High-definition image quality content can be viewed on the rear monitor 6.

  However, the above-mentioned terrestrial digital broadcast receiver requires four antennas, four tuners, and four OFDM demodulation units for two monitors, and the diversity combining unit needs to be the same number as the number of monitors. is there. For this reason, there has been a problem that the circuit scale is increased and the cost of parts is increased, which makes the terrestrial digital broadcast receiver expensive.

On the other hand, in a two-screen TV receiver that displays two screens on one TV receiver, an antenna with a good reception state is selected from a plurality of antennas and used to receive one screen, and the remaining antennas are used. There are known a technique for performing diversity reception using the technique and a technique for performing diversity reception by assigning a plurality of antennas to reception of two screens (for example, Patent Document 1).
JP-A-11-252474

  However, since the technique described in Patent Document 1 requires a larger number of antennas for the same number of tuners as the screen in order to display a plurality of screens, the circuit scale increases and the cost of components increases. As a result, the receiver becomes expensive. There is also a problem that high-definition image quality cannot be received because diversity combining is not performed.

  The present invention has been made to solve such problems, and is necessary for enabling high-definition content to be viewed in a terrestrial digital broadcast receiver that displays content on a plurality of monitors. The purpose is to reduce the circuit cost and the cost of parts.

  In order to solve the above-described problems, the present invention includes a number of antennas, tuners, and OFDM demodulation units corresponding to a plurality of monitors, and when viewing the same content of digital terrestrial broadcasting on a plurality of monitors, or When viewing terrestrial digital broadcast content from only one monitor among a plurality of monitors, diversity output of TSs output from a plurality of OFDM demodulation units is performed. When viewing different contents of terrestrial digital broadcasting on a plurality of monitors, TSs output from a plurality of OFDM demodulation units are output to the corresponding monitors.

  According to the present invention configured as described above, when viewing different contents on a plurality of monitors, by using a plurality of sets of antennas, tuners, and OFDM demodulation units corresponding to the plurality of monitors, respectively. A plurality of sets of antennas, tuners, and OFDM demodulation units used for diversity combining can be used for reception for a plurality of monitors, thereby reducing the number of antennas, tuners, OFDM demodulation units, and diversity combining units. In addition, the circuit scale can be reduced and the cost of components can be reduced. When viewing content on one of a plurality of monitors or viewing the same content on a plurality of monitors, a plurality of sets of antennas, tuners, and OFDM demodulation units are used for diversity combining. Thus, high-definition image content can be received and diversity combined, so that high-definition image content can be viewed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a terrestrial digital broadcast receiver according to the present embodiment. In FIG. 1, 11 is a first antenna and 12 is a second antenna. The first antenna 11 and the second antenna 12 receive radio waves of terrestrial digital broadcasting.

  Reference numeral 13 denotes a first tuner which is connected to the first antenna 11 and selectively extracts a signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast radio wave received by the first antenna 11. And output. Reference numeral 14 denotes a second tuner which is connected to the second antenna 12 and selectively extracts a signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast radio wave received by the second antenna 12. And output.

  Reference numeral 15 denotes a first OFDM demodulator, which obtains TS by OFDM demodulating the signal received by the first tuner 13. Reference numeral 16 denotes a second OFDM demodulator, which obtains TS by OFDM demodulating the signal received by the second tuner 14. Here, the first OFDM demodulator 15 and the second OFDM demodulator 16 can switch between reception of a weak layer (for example, 12 segments) and reception of a strong layer (for example, 1 segment).

  Reference numeral 17 denotes a diversity combining unit, which includes a phase shifter 17a, a combiner 17b, and a switch 17c. When the switch 17c is on the (1) side, the diversity combiner 17 controls the phase of the TS input from the first OFDM demodulator 15 by the phase shifter 17a, and the phase-controlled TS and the second OFDM demodulator The TS input from the unit 16 is synthesized by the synthesizer 17b. Then, the synthesized TS is output to the first error correction unit 18 described later. Here, the reception frequencies of the first tuner 13 and the second tuner 14 are the same frequency.

  On the other hand, when the switch 17c is on the (2) side, the diversity combining unit 17 outputs the TS input from the first OFDM demodulating unit 15 to the first error correcting unit 18 (to be described later) as it is and performs the second OFDM demodulation. The TS input from the unit 16 is output to the second error correction unit 19 described later. Here, the reception frequencies of the first tuner 13 and the second tuner 14 are different frequencies.

  Reference numeral 18 denotes a first error correction unit, which corrects an error for the TS combined by the diversity combining unit 17 when the switch 17c of the diversity combining unit 17 is on the (1) side. In addition, when the switch 17c of the diversity combining unit 17 is on the (2) side, the first error correcting unit 18 inputs the TS input from the first OFDM demodulating unit 15 in the diversity combining unit 17 as it is, and the error is corrected. Is corrected. Reference numeral 19 denotes a second error correction unit for correcting an error with respect to the TS output from the second OFDM demodulation unit 16 when the switch 17c of the diversity combining unit 17 is on the (2) side. It is.

  Reference numeral 20 denotes a demultiplexer unit. When the switch 17c of the diversity combining unit 17 is on the (1) side, the TS input from the first error correction unit 18 is separated, and the first video stream and the first audio are separated. Get a stream and output it. Further, when the switch 17c of the diversity combining unit 17 is on the (2) side, the demultiplexer unit 20 separates the TS input from the first error correction unit 18, and outputs the second video stream and the second audio. Get a stream and output it. Also, the TS input from the second error correction unit 19 is separated to obtain the third video stream and the third audio stream, and output them.

  Reference numeral 21 denotes a first audio decoder, which decodes an audio stream that matches a channel designated by the user and outputs it as front audio. For example, when the switch 17c of the diversity combining unit 17 is on the (1) side, the first audio decoder unit 21 decodes the first audio stream and outputs it as front audio. When the switch 17c of the diversity combining unit 17 is on the (2) side, the first audio decoder unit 21 decodes the second audio stream and outputs it as front audio.

  A first video decoder 22 decodes a video stream that matches a channel specified by the user and outputs it as a front video. For example, when the switch 17c of the diversity combining unit 17 is on the (1) side, the first video decoder unit 22 decodes the first video stream and outputs it as a front video. When the switch 17c of the diversity combining unit 17 is on the (2) side, the first video decoder unit 22 decodes the second video stream and outputs it as a front video.

  Reference numeral 23 denotes a second audio decoder which decodes an audio stream that matches a channel designated by the user and outputs it as rear audio. For example, when the switch 17c of the diversity combining unit 17 is on the (1) side, the second audio decoder unit 23 decodes the first audio stream and outputs it as rear audio. When the switch 17c of the diversity combining unit 17 is on the (2) side, the second audio decoder unit 23 decodes the third audio stream and outputs it as rear audio.

  Reference numeral 24 denotes a second video decoder, which decodes a video stream that matches a channel designated by the user and outputs it as a rear video. For example, when the switch 17c of the diversity combining unit 17 is on the (1) side, the second video decoder unit 24 decodes the first video stream and outputs it as a rear video. When the switch 17c of the diversity combining unit 17 is on the (2) side, the second video decoder unit 24 decodes the third video stream and outputs it as a rear video.

  Reference numeral 25 denotes a control unit, which sets a channel received by the first tuner 13 and the second tuner 14 by a control signal input by an operation of a remote controller or the like (not shown) provided outside. The control unit 25 receives information such as a reception state from the first tuner 13 and the second tuner 14 and outputs the information to the outside. Further, the control unit 25 selects the reception hierarchy of the first OFDM demodulator 15 and the second OFDM demodulator 16. The terrestrial digital broadcast receiver of the present embodiment configured as described above is implemented as, for example, the terrestrial digital broadcast receiver 1 of the rear entertainment system shown in FIG.

  FIG. 2 is a flowchart showing the operation of the terrestrial digital broadcast receiver and the terrestrial digital broadcast reception method according to this embodiment. First, the control unit 25 checks whether reception of terrestrial digital broadcast is selected by a source selection unit (not shown) provided in the front monitor 5 or a remote controller for the front monitor 5 (step S1). If reception of terrestrial digital broadcast is not selected on front monitor 5 and a signal from navigation device 2 or DVD playback device 3 is selected or nothing is selected (NO in step S1), control unit 25 Checks whether reception of terrestrial digital broadcasting is selected by a source selection unit (not shown) provided in the rear monitor 6 or a remote controller for the rear monitor 6 (step S2).

  If reception of terrestrial digital broadcast is not selected on rear monitor 6 and a signal from navigation device 2 or DVD playback device 3 is selected or nothing is selected (NO in step S2), processing in step S1 Return to.

  When reception of terrestrial digital broadcast is selected by the source selection unit (not shown) provided in the rear monitor 6 or the remote controller for the rear monitor 6 in step 2 (YES in step S2), the control unit 25 The reception frequency of the first tuner 13 and the second tuner 14 is set to a frequency that matches the channel selected by the channel selection unit (not shown) provided in the rear monitor 6 or the remote controller for the rear monitor 6, and the first The reception layer of the OFDM demodulator 15 and the second OFDM demodulator 16 is switched to reception of a weak layer (for example, 12 segments), and the switch unit 17c of the diversity combining unit 17 is switched to the (1) side.

  The phase of the TS input from the first OFDM demodulator 15 is controlled by the phase shifter 17a, and the phase-controlled TS and the TS input from the second OFDM demodulator 16 are combined by the combiner 17b. Thereby, the synthesized TS is error-corrected by the first error correction unit 19 and separated into an audio stream and a video stream by the demultiplexer 20. The separated audio stream and video stream are decoded by the second audio decoder unit 23 and the second video decoder unit 24 and output to the rear monitor 6 (step S3). Then, the process returns to step S1.

  On the other hand, when reception of terrestrial digital broadcast is selected by the source selection unit (not shown) provided in the front monitor 5 or the remote controller for the front monitor 5 (YES in step S1), the rear monitor 6 or the rear monitor 6 It is checked whether reception of terrestrial digital broadcasting is selected by a source selection unit (not shown) provided in the remote controller for use (step S4).

  Reception of the terrestrial digital broadcast is not selected by the source selection unit (not shown) provided in the rear monitor 6 or the remote controller for the rear monitor 6, and a signal from the navigation device 2 or the DVD playback device 3 is selected. If it is not selected (NO in step S4), the control unit 25 matches the channel selected by the channel selection unit (not shown) provided in the front monitor 5 or the remote controller for the front monitor 5. The reception frequencies of the first tuner 13 and the second tuner 14 are set, and the reception layers of the first OFDM demodulator 15 and the second OFDM demodulator 16 are switched to reception of weak layers (for example, 12 segments), The switch unit 17c of the diversity combining unit 17 is switched to the (1) side.

  The diversity combining unit 17 controls the phase of the TS input from the first OFDM demodulating unit 15 by the phase shifter 17a, and combines the phase-controlled TS and the TS input from the second OFDM demodulating unit 16. It is synthesized by the device 17b. Thus, the synthesized TS is error-corrected by the first error correction unit 19 and separated into an audio stream and a video stream by the demultiplexer 20. The separated audio stream and video stream are decoded by the first audio decoder unit 21 and the first video decoder unit 22 and output to the front monitor 5 (step S5). Then, the process returns to step S1.

  On the other hand, when reception of terrestrial digital broadcasting is selected by a source selection unit (not shown) provided in the rear monitor 6 or a remote controller for the rear monitor 6 (YES in step S4), the front monitor 5 or the front monitor 5 It is checked whether the channel selection unit (not shown) provided for use and the channel of the terrestrial digital broadcast selected by the rear monitor 6 or the channel selection unit (not shown) provided for the rear monitor 6 are different channels. (Step S6).

  If the channels selected by both are the same (NO in step S6), the control unit 25 receives the first tuner 13 and the second tuner 14 at a frequency matching the channel selected by both. The frequency is set, the reception layer of the first OFDM demodulation unit 15 and the second OFDM demodulation unit 16 is switched to reception of a weak layer (for example, 12 segments), and the switch unit 17c of the diversity combining unit 17 is set to the (1) side. Switch.

  The diversity combining unit 17 controls the phase of the TS input from the first OFDM demodulating unit 15 by the phase shifter 17a, and combines the phase-controlled TS and the TS input from the second OFDM demodulating unit 16. It is synthesized by the device 17b. Thus, the synthesized TS is error-corrected by the first error correction unit 19 and separated into an audio stream and a video stream by the demultiplexer 20. The separated audio stream and video stream are decoded by the first audio decoder unit 21 and the first video decoder unit 22 and output to the front monitor 5, and the second audio decoder unit 23 and the second video stream are also output. The video decoder 24 decodes the data and outputs it to the rear monitor 6 (step S7). Then, the process returns to step S1.

  The channel selection unit (not shown) provided in the front monitor 5 or the remote controller for the front monitor 5 and the channel selection unit (not shown) provided in the rear monitor 6 or the remote controller for the rear monitor 6 If the channel of the digital wave broadcasting is a different channel (YES in step S6), the control unit 25 is selected by the channel selection unit (not shown) provided in the front monitor 5 or the remote controller for the front monitor 5. The reception frequency of the first tuner 13 is set to a frequency that matches the channel, and the second frequency is set to the frequency that matches the channel selected by the channel selection unit (not shown) provided in the rear monitor 6 or the remote controller for the rear monitor 6. The receiving frequency of the tuner 14 is set. In addition, the control unit 25 switches the reception layer of the first OFDM demodulation unit 15 and the second OFDM demodulation unit 16 to reception of a strong layer (for example, one segment). Further, the control unit 25 stops the operation of the phase shifter 17a and the combiner 17b of the diversity combining unit 17, and switches the switch unit 17c to the (2) side (step S8).

  The diversity combiner 17 outputs the TS input from the first OFDM demodulator 15 to the first error corrector 18 and the TS input from the second OFDM demodulator 16 to the second error corrector 19. Output (step S9).

  The TS input to the first error correction unit 18 is error-corrected and output to the demultiplexer 20. The demultiplexer 20 separates the TS input from the first error correction unit 18 into a first audio stream and a first video stream. Then, the first audio stream is output to the first audio decoder unit 21, and the first video stream is output to the first video decoder unit 22. The demultiplexer 20 separates the TS input from the second error correction unit 19 into a second audio stream and a second video stream. Then, the second audio stream is output to the second audio decoder unit 23, and the second video stream is output to the second video decoder unit 24.

  The first audio decoder unit 21 decodes the first audio stream and outputs it as front audio. The first video decoder unit 22 decodes the first video stream and outputs it as a front video. Further, the coder unit 23 decodes the second audio stream with the second audio and outputs it as rear audio. Furthermore, the second video decoder unit 24 decodes the second video stream and outputs it as a rear video (step S10).

  As described above in detail, according to the present embodiment, when viewing different terrestrial digital broadcast contents on the front monitor 5 and the rear monitor 6, the first antenna 11, the first tuner 13, and the first OFDM are used. The demodulator 15 is used in correspondence with the front monitor 5, the second antenna 12, the second tuner 14 and the second OFDM demodulator 16 are used in correspondence with the rear monitor 6, and the first OFDM demodulation. The reception layer of the unit 15 and the second OFDM demodulation unit 16 is switched to the strong layer. Accordingly, a set of the first antenna 11, the second antenna 12, the first tuner 13, the second tuner 14, the first OFDM demodulator 15, and the second OFDM demodulator 16 used for diversity combining. The diversity synthesizer 17 can be used to receive different terrestrial digital broadcast contents and view them on the front monitor 5 and the rear monitor 6, respectively.

  Also, according to the present embodiment, when viewing terrestrial digital broadcast content on either the front monitor 5 or the rear monitor 6, or viewing the same terrestrial digital content on the front monitor 5 and the rear monitor 6. In this case, the reception layer of the first OFDM demodulator 15 and the second OFDM demodulator 16 is switched to the weak layer, the TS output from the first OFDM demodulator 15 and the output from the second OFDM demodulator 16 By inputting the TS to the diversity combining unit 17 and performing diversity combining, it is possible to receive terrestrial digital broadcast content with high definition image quality.

  That is, according to the present embodiment, it is possible to receive different contents for front and rear using only a set of circuits (first antenna 11 to diversity combining unit 17) used for diversity combining. It is also possible to receive content with high definition image quality. Therefore, the circuit scale can be reduced, and the cost of parts can be reduced.

  In the above-described embodiment, whether to perform diversity combining is switched by switching the switch unit 17c of the diversity combining unit 17 to the (1) side or (2) side, but is not limited to this. For example, a means for switching the TS input from the first OFDM demodulator 15 and the second OFDM demodulator 16 to the diversity combiner 17 may be provided separately.

  For example, as shown in FIG. 3, a switching unit 29 and a diversity combining unit 30 that performs diversity combining are provided after the first OFDM demodulating unit 15 and the second OFDM demodulating unit 16. When reception of the terrestrial digital broadcast is selected by either the front monitor 5 or the rear monitor 6, or when reception of the same channel is selected by both the front monitor 5 and the rear monitor 6, the switching unit With 29 switches set to the (1) side, diversity combining is performed by the phase shifter 30a and the combiner 30b of the diversity combining unit 30. When reception of different channels is selected by the front monitor 5 and the rear monitor 6, the switch of the switching unit 29 is set to the (2) side so that the TS is not input to the diversity combining unit 30, and the first The TS from the OFDM demodulator 15 is output to the first error corrector 18, and the TS from the second OFDM demodulator 16 is output to the second error corrector 19. This eliminates the need to control the operations of the phase shifter 27a and the combiner 27b of the diversity combiner 27.

  Moreover, although the said embodiment demonstrated the terrestrial digital broadcast receiver with respect to the two monitors of the front monitor 5 and the rear monitor 6, the number of monitors and an installation place are not limited to this. For example, as shown in FIG. 4, when three monitors are installed, a third antenna 26, a third tuner 27, a third OFDM demodulator 28, a switching unit in addition to the configuration of FIG. 29, a third error correction unit 31, a third audio decoder unit 32, and a third video decoder unit 33 are prepared. Further, a diversity combining unit 30 is used instead of the diversity combining unit 17.

  When viewing the same channel with three monitors or viewing with only one of the three monitors, the reception of the first tuner 13, the second tuner 14, and the third tuner 27 is performed. The same frequency is used, and the reception hierarchy of the first OFDM demodulator 15, the second OFDM demodulator 16, and the third OFDM demodulator 28 is a weak hierarchy. The switch 29a of the switching unit 29 is set to the (2) side, the switch 29b is set to the (1) side, and the switch 29c is set to the (1) side.

  The diversity combining unit 30 converts the phase of the TS input from the first OFDM demodulator 15 through the switching unit 29 and the phase of the TS input from the second OFDM demodulator 16 through the switching unit 29 into a phase shifter 30a, The combiner 30c performs diversity combining of these phase-controlled TSs and the TS output from the third OFDM demodulator 28. Then, the diversity combined TS is error-corrected by the first error correction unit 18, and the TS is separated into an audio stream and a video stream by the demultiplexer 20, and then each stream is decoded and three monitors or Output to one of the monitors.

  When viewing different channels on the three monitors, the reception frequencies of the three tuners 13, 14, and 27 are set to the frequencies of the selected channels, and the first OFDM demodulator 15 and the second OFDM demodulator. The reception hierarchy of the 16th and third OFDM demodulator 28 is a strong hierarchy. The switch 29a of the switching unit 29 is set to the (1) side, the switch 29b is set to the (2) side, and the switch 29c is set to the (2) side.

  The outputs of the first OFDM demodulator 15, the second OFDM demodulator 16, and the third OFDM demodulator 28 are sent via the switching unit 29 to the first error corrector 18, the second error corrector 19, and the 3 are respectively input to the error correction unit 31 and error correction is performed. The error-corrected TS is separated into an audio stream and a video stream by the demultiplexer 20 and then output to the decoders 21 to 24, 32, and 33. Then, the audio decoded by the first audio decoder 21 and the video decoded by the first video decoder 22 are output for the first monitor. Also, the audio decoded by the coder unit 23 with the second audio and the video decoded by the second video decoder unit 24 are output for the second monitor. Furthermore, the audio decoded by the third audio decoder 32 and the video decoded by the third video decoder 33 are output for the third monitor.

  In addition, when viewing the same channel on two of the three monitors, or viewing only on two of the three monitors and viewing a different channel on the two monitors, In order to view a channel (for example, a high-definition image quality channel), the reception frequencies of the first tuner 13 and the third tuner 27 are set to the same frequency, and the first OFDM demodulator 15 and the third OFDM demodulator 28 The reception layer is a weak layer. The switch 29a of the switching unit 29 is set to the (2) side, the switch 29b is set to the (2) side, and the switch 29c is set to the (1) side.

  The diversity combining unit 30 controls the phase of the TS input from the first OFDM demodulator 15 through the switching unit 29 by the phase shifter 30 a, and the phase-controlled TS and the output from the third OFDM demodulator 28. Diversity synthesis is performed with the TS to be synthesized by the synthesizer 30c. Then, the diversity combined TS is error-corrected by the first error correction unit 18, and the TS is separated into an audio stream and a video stream by the demultiplexer 20. Output to both or one of the two monitors.

  In addition, the second antenna 12 and the second tuner 14 are used to view the other channel, and the reception hierarchy of the second OFDM demodulator 16 is set as a strong hierarchy. The output of the second OFDM demodulator 16 is input to the second error correction unit 19 via the switching unit 29 and is error-corrected. The error-corrected TS is separated into an audio stream and a video stream by the demultiplexer 20, and then output to a decoder connected to a monitor other than the monitor for viewing the one channel. Then, the decoded audio and video are output to a monitor for viewing the other channel. As a result, even when a plurality of monitors are used, it is possible to combine viewing channels and image quality in various combinations.

  In addition, the said embodiment is only what showed the example in implementation in implementing this invention, and, as a result, the technical scope of this invention should not be interpreted limitedly. In other words, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

  The present invention is useful for a terrestrial digital broadcast receiver that outputs different contents to a plurality of monitors and outputs high-definition image quality contents to at least one monitor.

It is a block diagram which shows the structural example of the terrestrial digital broadcast receiver by this embodiment. It is a flowchart which shows the operation | movement of the terrestrial digital broadcasting receiver by this embodiment, and the terrestrial digital broadcasting receiving method. It is a figure which shows the modification of the diversity synthetic | combination part of the terrestrial digital broadcast receiver by this embodiment. It is a block diagram which shows the modification of the terrestrial digital broadcast receiver by this embodiment. It is a block diagram which shows the structural example of the conventional terrestrial digital broadcasting receiver. It is a block diagram which shows the other structural example of the conventional terrestrial digital broadcasting receiver. It is a block diagram which shows the structural example of the rear entertainment system to which the terrestrial digital broadcasting receiver is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Terrestrial digital broadcasting receiver 2 Navigation apparatus 3 DVD reproducing apparatus 4 Interface box 5 Front monitor 6 Rear monitor 11 1st antenna 12 2nd antenna 13 1st tuner 14 2nd tuner 15 1st OFDM demodulation part 16 Second OFDM demodulator 17 Diversity combiner 17a Phase shifter 17b Combiner 18 First error corrector 19 Second error corrector 20 Demultiplexer 21 First audio decoder 22 First video decoder 23 Second Audio decoder unit 24 second video decoder unit 25 control unit

Claims (5)

A terrestrial digital broadcast receiver that receives terrestrial digital broadcast of a desired channel and outputs content to n (n is an integer of 1 or more) monitors,
N antennas for receiving terrestrial digital broadcast radio waves;
N tuners respectively connected to the n antennas, setting a reception frequency matching the desired channel, and receiving a broadcast signal of the channel;
N OFDM demodulator units that respectively receive signals from the n tuners and perform OFDM demodulation;
Diversity combining the transport streams input from the n OFDM demodulator units, or a diversity combiner unit that passes as it is,
A control unit configured to set a channel to be received for the n tuners and to control whether the diversity combining unit performs diversity combining;
When outputting content to only one monitor from among the n monitors, or when outputting content of the same channel to the n monitors, the control unit sets all the n tuners to the same channel. When the diversity combining unit controls the transport stream output from the n OFDM demodulating units to diversity combine, and outputs the content of different channels to the n monitors, the control The unit sets the n tuners to the different channels, the diversity combining unit stops the diversity operation, and the transport stream output from the n OFDM demodulation units is sent to the n monitors. Terrestrial digital, characterized by control to output in response Transceiver. A terrestrial digital broadcast receiver that receives terrestrial digital broadcast of a desired channel and outputs content to n (n is an integer of 1 or more) monitors,
N antennas for receiving terrestrial digital broadcast radio waves;
N tuners respectively connected to the n antennas, setting a reception frequency matching the desired channel, and receiving a broadcast signal of the channel;
N OFDM demodulator units that respectively receive signals from the n tuners and perform OFDM demodulation;
A diversity combining unit for diversity combining the transport streams input from the n OFDM demodulation units;
A switching unit for switching whether to output the transport stream output from the n OFDM demodulation units to the diversity combining unit;
A control unit that sets a channel to be received for the n tuners and controls the switching unit;
When outputting content to only one monitor from among the n monitors, or when outputting content of the same channel to the n monitors, the control unit sets all the n tuners to the same channel. Is set so that the switching unit outputs the transport stream to the diversity combining unit, the diversity combining unit diversity combines the transport streams output from the n OFDM demodulation units, When outputting content of different channels to the n monitors, the control unit sets the n tuners to the different channels, and the switching unit does not output the transport stream to the diversity combining unit. The switching unit is Terrestrial digital broadcasting receiver and outputting by a transport stream in correspondence with said n monitor output from the n OFDM demodulator. The n OFDM demodulation units can switch the received layer to a weak layer or a strong layer,
When outputting content to only one monitor among the n monitors, or outputting content of the same channel to the n monitors, the control unit receives the n OFDM demodulation units. 2. The control unit according to claim 1, wherein when the layer to be performed is a weak layer and contents of different channels are output to the plurality of monitors, the control unit sets the layer received by the n OFDM demodulation units as a strong layer. Alternatively, a terrestrial digital broadcast receiver according to claim 2. A terrestrial digital broadcast receiving method for receiving terrestrial digital broadcast of a desired channel and outputting contents to n (n is an integer of 1 or more) monitors,
A first step of checking whether to output content to only one monitor among the n monitors;
If it is determined in the first step that content is output to only one monitor among the n monitors, all n tuners are set to the same channel and output from the n tuners. A second step of performing OFDM demodulation on the signal by n OFDM demodulation units and diversity combining the resulting transport stream;
If it is determined in the first step that content is to be output to the n monitors, a third step of checking whether the content is content of the same channel;
When it is determined in the third step that the content to be output to the n monitors is the content of the same channel, the signals output from the n tuners are OFDM demodulated by the n OFDM demodulation units. And a fourth step of diversity combining the transport stream obtained thereby,
When it is determined in the third step that the content to be output to the n monitors is content of a different channel, the signals output from the n tuners are OFDM demodulated by the n OFDM demodulation units. A fifth step of outputting n transport streams obtained thereby in correspondence with the n monitors;
A terrestrial digital broadcast receiving method comprising: In the second step and the fourth step, a layer received by the n OFDM demodulator units is set as a weak layer, and in the fifth step, a layer received by the n OFDM demodulator units is set. 5. The terrestrial digital broadcast receiving method according to claim 4, wherein the layer is a strong hierarchy.

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