JP2007295229A - Digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast receiver having receiving performance which can be maintained by determining and dissolving the presence of the same channel interference when receiving the same channel by a plurality of digital tuners during the channel scanning of terrestrial digital broadcasting. <P>SOLUTION: The digital broadcast receiver acquires receivable channels in the channel scanning of terrestrial digital broadcasting (S202). The presence of the same channel interference is determined (S202), and only when the determination is YES, the presence of the same channel interference is stored (S203). Then, the same channel interference is dissolved (S204). Thus, performance degradation in receiving the same channel is determined and dissolved and the receiving performance is secured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital broadcast receiving apparatus used for digital broadcasting.

In a digital terrestrial broadcast receiving apparatus equipped with a plurality of digital tuners, when each tuner is mechanically laid out in an adjacent position, the same channel interference that the local frequency of each tuner interferes and reception performance deteriorates occurs. . Therefore, the reception performance (ARIB-B21 (non-patent document) is established by installing each tuner at a position away from each other so as to prevent mechanical interference or by performing exclusive processing on the same channel reception itself by software control as known in Patent Document 1. (Refer to Document 1))).
Japanese Patent Laid-Open No. 5-137086 ARIB STD-B21 Digital Broadcast Receiver Standard (desired specifications)

  However, in the conventional configuration described above, while space saving is progressing as a receiver, it is difficult to install a plurality of digital tuners at distant positions, and high-definition video can be displayed with the start of digital broadcasting. The use of recording simultaneously with viewing has increased rapidly, and the necessity of receiving the same channel has increased, so the conventional exclusive processing has a problem in specifications.

  The present invention solves the above-mentioned conventional problems, and determines and eliminates the presence or absence of interference on the same channel when receiving the same channel with a plurality of digital tuners during channel scanning of terrestrial digital broadcasting, thereby maintaining reception performance. It is an object of the present invention to provide a digital broadcast receiving apparatus capable of performing

In order to achieve this object, the digital broadcast receiving apparatus of the present invention is a digital broadcast receiving apparatus having a plurality of digital tuners, and obtains a receivable channel by scanning all frequencies of the digital broadcast and acquiring a receivable channel. And the same channel interference presence / absence determining means for determining the presence or absence of the same channel interference when a plurality of tuners select the same channel, and when the same channel interference presence / absence determining means determines that the same channel interference is present. Co-channel interference eliminating means for offsetting the local frequency of the tuner, means for storing the determination result of the co-channel interference presence determining means,
It has the composition provided with.

  Further, a configuration further comprising adjacent channel interference mitigation means for detecting a local offset when the reception performance is improved when the local offset value is changed as compared to when the local offset is made to the limit of the demodulation IC. have.

  As described above, the present invention has an excellent effect that it is possible to determine and eliminate the presence or absence of interference in the same channel when the same channel is received by a plurality of digital tuners during channel scanning of digital broadcasting, and to maintain reception performance. can get.

The present invention is a digital broadcast receiver having a function of scanning a digital broadcast channel and storing it in a channel list, and having a plurality of digital tuners, scans all frequencies of the digital broadcast and obtains a receivable channel And a means for judging presence / absence of interference on the same channel when a plurality of tuners select the same channel, a means for eliminating performance degradation due to this, and a means for storing the result. The digital broadcast receiving apparatus has the function of maintaining the reception performance by determining and eliminating the presence or absence of co-channel interference.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 1 of the present invention. Hereinafter, the configuration of the digital broadcast receiving apparatus will be described with reference to FIG. In this description, the case of having two digital tuners is taken as an example. A first digital tuner 101 that receives a user-selected signal, a second digital tuner 102, an IF signal detector 103 that detects the presence or absence of a signal level, a demodulator 104 that demodulates the modulated signal, and reception Reception performance measuring unit 105 for measuring performance (CN value or BER value), TS decoder 106 for separating the demodulated signal into video / audio / additional information, AV decoder for decoding the separated video signal / audio signal 107, a flash ROM 108 which is a storage device for storing programs and program information, a RAM 109 which is a storage device for storing internal information of programs, a storage device for storing user-specific information, system setting information of a digital broadcast receiving device, and the like EEPROM 110, an infrared remote control receiver for receiving remote control signals 111, and a CPU112 for controlling these devices via the system bus 100.

  FIG. 2 is a flowchart showing the operation of the digital broadcast receiving apparatus according to Embodiment 1 of the present invention. In the channel scan of terrestrial digital broadcasting, a receivable channel is acquired (step S201). It is determined whether or not there is interference with the same channel (step S202). Only in the case of Yes, the presence of the same channel interference is stored (step S203). Next, the same channel interference is eliminated (step S204). In this way, the performance degradation at the time of receiving the same channel is judged and eliminated, and the reception performance is ensured.

  FIG. 3 is a flowchart for determining the presence or absence of co-channel interference in the first embodiment of the present invention. As a process for determining whether or not there is interference with the same channel simultaneously with the channel scan, channel selection data for the channel first scanned by the first digital tuner 101 is set in step S321, and the process proceeds to step S322. Next, in step S322, the presence / absence of a synchronization signal (TS synchronization) of the TS decoder 106 is detected. If there is no TS synchronization, the process proceeds to step S324 to scan the next channel. If TS synchronization exists, step S323 is performed. This channel is added to the channel list as a receivable channel, and the channel list is stored in the EEPROM 110, and the process proceeds to step S324 to scan the next channel. Next, in step S324, if the scanned channel is the last channel, the process proceeds to step S326. If the scanned channel is not the last channel, the next channel to be scanned to the first digital tuner 101 in step S325. Channel selection data is set, and the process proceeds to step S322. Next, the reception performance value (CN value or BER value) at each digital tuner is measured, and in order to obtain the single reception performance value without interference on the same channel, in step S326, the channel list constructed at the time of scanning is obtained. The first channel is set as a channel for measuring reception performance. In step S327, the single performance of the first digital tuner 101 is measured. At this time, as in step S328, the second digital tuner 102 sets the channel that has not entered the scan list due to the sleep mode or TS synchronization so as not to receive the same channel. In step S329, the single reception performance value of the first digital tuner 101 is stored in the memory. The first channel of the channel list constructed at the time of scanning as in step S330 is selected by the second digital tuner 102. Similarly, as in step S331, the first digital tuner 101 has no sleep mode or TS synchronization and is in the scan list. A channel that does not appear is selected. In step S332, the single reception performance value of the second digital tuner 102 is stored in the memory. In step S333, the first digital tuner 101 and the second digital tuner 102 are selected on the same channel, and the respective reception performance values are measured. In step S334, the individual reception performance of each digital tuner is compared with the reception performance value at the time of channel selection. If there is no deterioration, the process proceeds to step S336 in order to select the next channel in the channel list. If there is degradation, the information is stored in the memory as “the same channel is disturbed”, and the process proceeds to step S336. In step S336, it is determined whether it is the last channel in the channel list. If it is not the last channel, the process proceeds to S337. If it is the last channel, the process for determining the presence or absence of the same channel is terminated.

FIG. 4 is a flowchart for eliminating co-channel interference in Embodiment 1 of the present invention. When the viewer performs a channel selection operation with the infrared remote control receiver 111 in step S431, in step S432, the presence / absence of the same channel interference is called from the memory and the processing is branched. If there is no interference on the same channel, normal local frequency information is transferred to the digital tuner, and the process proceeds to step S433. If there is co-channel interference, in step S434, the co-channel interference is eliminated by transferring data offset from the local frequency up or down to the limit value that the demodulating IC can pull into one digital tuner. The process proceeds to S435. When the reception is completed in step S435, the same channel interference elimination process is terminated. In the first embodiment, the channel list, reception performance value, and presence / absence of the same channel interference are stored in the memory. However, the storage destination may be the EEPROM 110 or the flash ROM 108.
(Embodiment 2)
A means for mitigating adjacent channel interference that may occur as a side effect when implementing the same channel interference cancellation of the first embodiment will be described. Adjacent channel interference refers to a phenomenon in which reception performance deteriorates when an RF signal of an adjacent channel is mixed as an interference wave in a pull-in range of a demodulation IC by offsetting a local frequency. Therefore, by measuring the appropriate value of the local offset amount, a means for reducing the side effect of eliminating the same channel interference is provided.

  FIG. 5 is a flowchart for alleviating the side effect of co-channel interference in Embodiment 2 of the present invention. By additionally performing after the processing flow of FIG. 3, the presence or absence of adjacent channel interference is determined, and an appropriate offset amount is determined. First, in step S541, a channel list is called from the memory, and in step S542, the presence or absence of an adjacent channel is determined, and the process is branched. If there is no adjacent channel, the process proceeds to step S548 to measure the next channel. If there is an adjacent channel, the process proceeds to step S543, and the data offset locally to the limit of the demodulation IC is transferred to one tuner. In step S544, the reception performance of the first digital tuner 101 and the second digital tuner 102 is measured and stored in the memory. In step S545, the local offset value is changed (for example, the limit value is decreased by 1 / N), and the reception performance is measured. In step S546, the process branches depending on whether or not the reception performance value obtained by offsetting to the limit value is improved. If not improved, the process proceeds to step S548 in order to measure the next channel while maintaining the same channel cancellation. If it is improved, the process proceeds to step S547, an appropriate local offset amount is stored in the memory, and the process proceeds to step S548. In step S548, it is determined whether the channel is the last channel. If the channel is not the last channel, the process proceeds to step S549, the next channel is set, and the process proceeds to step S542. If it is the last channel, the process ends. The adjacent channel interference mitigation process is completed by transferring the appropriate local offset amount stored in step S547 in step S434 of FIG.

  Embodiments 1 and 2 are not limited to fixed receivers as receivers, and the same applies to mobile receivers and partial receivers.

  The present invention is not limited to the embodiment described above.

  As described above, the function in the best mode for carrying out the present invention is realized by a predetermined program.

  The digital broadcast receiver of the present invention has an effect of solving reception performance degradation due to co-channel interference (local interference interference) at the time of digital co-channel reception, and is useful as a receiver used for digital broadcasting.

1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 1 of the present invention. The flowchart which shows operation | movement of the digital broadcast receiver in Embodiment 1 of this invention. Flowchart for determining presence or absence of co-channel interference in Embodiment 1 of the present invention Flowchart for eliminating co-channel interference in Embodiment 1 of the present invention Flowchart for mitigating the side effect of co-channel interference in Embodiment 2 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 System bus 101 1st digital tuner 102 2nd digital tuner 103 IF signal detection 104 Demodulator 105 Reception performance measuring device 106 TS decoder 107 AV decoder 108 Flash ROM
109 RAM
110 EEPROM
111 Infrared remote control receiver 112 CPU

Claims (2)

A digital broadcast receiver comprising a plurality of digital tuners,
Receivable channel acquisition means for scanning all frequencies of digital broadcasting and acquiring a receivable channel;
The same channel interference presence / absence judging means for judging the presence or absence of the same channel interference when a plurality of tuners select the same channel;
Co-channel jamming elimination means for offsetting the local frequency of one tuner when the co-channel jamming presence / absence judging means judges that there is co-channel jamming;
Means for storing a judgment result of the co-channel interference presence / absence judging means;
A digital broadcast receiving apparatus. The adjacent channel interference mitigation means for detecting a local offset when the reception performance is improved when the local offset value is changed as compared with when the local offset is made to the pull-in limit of the demodulation IC. Digital broadcast receiver.

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