JP2006303664A - Receiver and integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of stably executing handover. <P>SOLUTION: The receiver has a function for simultaneously receiving a plurality of channels, a function for separately switching each channel, a function for confirming each receiving state of a plurality of channels, a function for detecting an error of a signal, and a function for compositing data by selecting data without having errors from each received signal. The handover is executed while confirming the receiving state by changing the channel one by one with a plurality of receiving functions during the handover. A search time is reduced by finding a channel as a candidate from each receiving state by simultaneously receiving a plurality of the channels during the channel search. Each of a plurality of transmitters exists in the opposite direction viewed from the receiver since it exists near the boundary of a cell during the handover. Frequency/space diversity reception can be executed by selectively compositing both transmitting waves of the transmitters by receiving them. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives an OFDM (Orthogonal Frequency Division Multiplexing) signal, and more particularly to handover and diversity reception.

  In recent years, digital broadcasting using OFDM and the use of wireless LAN have begun in countries around the world, and OFDM technology is being used for next-generation mobile phones. In Japan, terrestrial digital television broadcasting using the ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system has been started, and in China, the DMB-T (Digital Multimedia Broadcast-Terrestrial) system is being developed. In particular, broadcasting using the DVB-T (Digital Video Broadcasting-Terrestrial) system has been started in an area mainly in Europe. Furthermore, based on this DVB-T system, a DVB-H (Digital Video Broadcasting-Handheld) system based on a service to mobile terminals has been formulated, and broadcasting is about to start. In order to receive these digital broadcasts while moving, it is necessary to perform a stable and uninterrupted handover when moving from a cell covered by one transmitter to a cell covered by another transmitter. It becomes. In particular, the DVB-H system places importance on reception by a moving body, and a smooth handover is desired.

  In Patent Document 1, as shown in the flowchart of FIG. 6, if the reception state becomes worse than a certain threshold, another channel is received, and if the reception state is good, handover is realized by changing to that channel.

  In addition, an all-channel search is performed when it is impossible to determine in which channel a broadcast that can be received at the current location is being performed, such as when a fixed reception terminal is installed or when a mobile reception terminal is powered on. As shown in the flowchart of FIG. 5, all the channels are received one by one, and a search for which channel is being broadcast is performed.

  In addition, handover is performed in the vicinity of the cell boundary, and the electric field strength of the channel being received is lowered near this boundary, and the reception state is not good. Diversity reception is known as a method for improving the reception state. In particular, in a scheme using OFDM, diversity reception can be performed for each carrier by utilizing the multicarrier.

  In Patent Document 2 and Patent Document 3, the reception state is improved by performing carrier combining diversity as shown in FIG. The first system 201 and the second system 211 receive OFDM signals of the same channel transmitted from the same transmitter, respectively, perform the respective processes, detect the signals in the detection unit 205 and the detection unit 215, and detect each carrier. Estimate the reliability. These are combined by the carrier combining unit 206 according to the reliability of each carrier, and the error correction unit 207 performs error correction and outputs it to the back end.

Further, in order to reduce frequency selective interference, a frequency diversity system that transmits the same program at a plurality of frequencies is known. In Patent Document 4, a frequency diversity method is used in which the same program is transmitted at a plurality of frequencies from the same direction. In Patent Document 5, a frequency diversity system for broadcasting a plurality of programs in the same channel is performed. As shown in FIG. 9, the frequency diversity receiving terminal 903 receives the signal of the channel of the frequency f1 and the signal of the frequency f2 transmitted from the transmitting antenna 901 and performs synthesis.
International Publication No. 03/073774 Pamphlet Japanese Patent No. 3377361 Japanese Patent No. 3389178 Japanese Patent No. 30228865 Japanese Patent No. 3112659

  However, in the above-described conventional configuration, handover occurs because the area boundary where the reception state is unstable, the radio wave state of each area changes drastically due to mountains, buildings, and the like. For this reason, the handover is frequently repeated and reception is frequently interrupted.

  In addition, when receiving is continued, what broadcasting service is performed on which channel based on information (NIT: Network Information Table) for notifying what kind of broadcasting is being performed in neighboring cells. Can be determined. However, when such information cannot be used, for example, when the power is turned on or when returning from a place where radio waves cannot be received for a long period of time, it is necessary to perform a channel search to find out what kind of broadcast is being performed on which channel. . At this time, since all the channels are searched one by one, there is a problem that it takes time.

  In addition, in conventional carrier synthesis diversity reception, the reliability for each carrier is estimated and combined, but the reliability is merely “predicted” from the signal amplitude and constellation dispersion of each carrier, and not necessarily There was a problem that the composition for reducing the occurrence of reception errors was not achieved.

  In addition, as shown in FIG. 10, when frequency diversity is performed by transmitting signals of frequency f1 and frequency f2 from the transmitting antenna 901 in the same direction, the frequency diversity receiver 903 is moved to a mountain or a building while moving. When entering the shade of the shield 904, there is a problem that the transmission waves of a plurality of frequencies are both blocked and cannot be received, and there is no frequency diversity effect.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide a receiving apparatus that repeats handover frequently and performs handover without frequent interruption of reception.

  It is another object of the present invention to provide a receiving apparatus capable of completing all channel searches in a short time. Furthermore, it aims at providing the receiver which performs diversity reception which reduces generation | occurrence | production of a reception error.

  It is another object of the present invention to provide a receiving apparatus that can stably receive even in an environment where a transmission wave is blocked by a shield such as a mountain or a building during movement.

  In order to solve the above-described conventional problems, the receiving apparatus of the present invention has a function of simultaneously receiving a plurality of channels, a function of switching each channel independently, a function of checking each reception state, It has a function of detecting an error and a function of selecting and synthesizing data having no error from each received signal.

  During handover, a plurality of reception functions change channels one by one and perform handover while checking the reception state.

  Also, during channel search, a plurality of channels are received simultaneously, and candidate channels are found from the respective reception states, thereby shortening the search time.

  In addition, since a plurality of transmitters exist in opposite directions when viewed from the receiving device at the time of handover, the frequency and space diversity are received by receiving and combining both of the transmission waves.

  With this configuration, it is possible to realize a receiving apparatus that performs handover without frequent interruption due to frequent occurrence of handover in mobile reception. Furthermore, it is possible to realize a receiving apparatus that can complete a channel search in a short time.

  Furthermore, it is possible to realize a receiving apparatus that can reduce the occurrence of reception errors.

  According to the receiving apparatus of the present invention, the channel is changed for each system at the time of handover, and the handover is performed while checking the reception state, so that the handover frequently occurs and the reception is not interrupted frequently. Handover can be realized.

  Further, during channel search, a plurality of channels are received simultaneously, and candidate channels are found from the respective reception states, thereby shortening the search time.

  In addition, it is possible to reduce the occurrence of reception errors by detecting errors in received signals for each of a plurality of channels and selectively combining data that has been confirmed to have no errors.

  In addition, since the transmitter is located near the cell boundary at the time of handover, a plurality of transmitters exist in opposite directions as viewed from the receiving device, so both of the transmission waves are received and selectively combined. By doing so, frequency and space diversity effects can be obtained, so that even if one transmitted wave is blocked by a mountain or building, it can be received stably.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram of a front end portion of a DVB-H receiving apparatus according to Embodiment 1 of the present invention. A description of a back end that performs decoding of video and audio signals, a video display device, an audio playback device, and the like will be omitted.

  The receiving apparatus shown in FIG. 1 has a first system 100 and a second system 101 that perform transmission signal selection, detection, error correction, and the like, and perform channel selection independently in each system. The channel signal is received, synthesized by the frame synthesizing unit 130, and MPE-FECRS correction unit 131 performs DVB-H MPE-FEC RS (Reed Solomon) decoding, and outputs it to the back end.

  Next, the first system 100 will be described. An OFDM signal is received by the antenna 110, and a channel desired to be received by the tuner unit 111 is selected and down-converted. The channel to be selected is instructed from the channel selection control unit 140. The output of the tuner unit 111 is sent to the FFT unit 113 and the synchronization unit 112, and the FFT unit 113 performs Fourier transform to convert the signal from the time domain to the frequency domain. The output of the FFT unit 113 is also input to the synchronization unit 112 to perform time axis synchronization and frequency synchronization. The synchronization result in the synchronization unit 112 is sent to the synchronization state detection unit 117, and the type of the received signal (transmission mode, guard interval length, synchronization stability, etc.) is determined and sent to the channel selection control unit 140. Next, the signal converted into the frequency domain by the FFT unit 113 is sent to the detection unit 114 to perform detection processing. The signal being detected is sent to the C / N measuring unit 118, C / N is measured, and the result is sent to the channel selection control unit 140. The result detected by the detection unit 114 is sent to the error correction unit 115, which performs deinterleaving, error correction, etc., and generates a TS (Transport Stream) signal. This TS signal is input to the CRC check unit 116. This TS signal uses a CRC (Cyclic Redundancy Check) that is an error detection code for each packet, and the CRC check unit 116 determines whether or not there is an error in the packet received using this CRC. Is detected and output to the frame synthesizing unit 130.

  The second system 101 performs the same processing as the first system 100 as described below. An OFDM signal is received by the antenna 120, and a channel desired to be received by the tuner unit 121 is selected and down-converted. The channel to be selected is instructed from the channel selection control unit 140. The output of the tuner unit 121 is sent to the FFT unit 123 and the synchronization unit 122, and the FFT unit 123 performs Fourier transform to convert the signal from the time domain to the frequency domain. The output of the FFT unit 123 is also input to the synchronization unit 122 to perform time axis synchronization and frequency synchronization. The synchronization result in the synchronization unit 122 is sent to the synchronization state detection unit 127, and the type of the received signal (transmission mode, guard interval length, synchronization stability, etc.) is judged and sent to the channel selection control unit 140. Next, the signal converted into the frequency domain by the FFT unit 123 is sent to the detection unit 124 to perform detection processing. The signal being detected is sent to the C / N measurement unit 128, C / N is measured, and the result is sent to the channel selection control unit 140. The result detected by the detection unit 124 is sent to the error correction unit 125, which performs deinterleaving, error correction, and the like to generate a TS (Transport Stream) signal. This TS signal is input to the CRC check unit 126. This TS signal uses CRC (Cyclic Redundancy Check) which is an error detection code for each packet, and the CRC check unit 126 determines whether there is an error in the packet received using this CRC, It is labeled whether an error has been detected and output to the frame synthesis unit 130.

  The tuning control unit 140 receives the outputs of the synchronization state detection unit 117, the C / N measurement unit 118 of the first system 100, the synchronization state detection unit 127 of the second system 101, and the C / N measurement unit 128, and the memory unit 141, the information of each channel is recorded and read out, the channel to be received by the first system 100 and the second system 101 is determined, and the channel selection signal is sent to the tuner unit 111 and the tuner unit 121 to switch the channel. .

  The frame synthesizing unit 130 selects a packet in which no error is detected in the TS signals output from the first system 100 and the second system 101, and performs MPE-FEC RS correction.

  Next, a description will be given of an operation in which a moving receiving apparatus performs handover in an environment in which broadcasts having the same content are transmitted in adjacent service areas using channels having different frequencies. FIG. 8 illustrates an environment in which the DVB-H receiving apparatus 803 according to Embodiment 1 of the present invention receives data while moving across the service area. When a signal broadcast from the transmission antenna 801 on the channel of the frequency f1 is received near the transmission antenna 801, the DVB-H reception device 803 receives only the channel of the frequency of f1. When the DVB-H receiving device 803 moves toward the transmitting antenna 802 and the signal from the transmitting antenna 801 becomes weak, the DVB-H receiving device 803 receives the frequency f1 channel transmitted from the transmitting antenna 801 and Both of the channels of the frequency f2 transmitted from the transmitting antenna 802 are received and combined. Since signals in a plurality of directions are received in this way, even if the DVB-H receiver 803 enters behind the shield 804 and cannot receive the signal from the transmission antenna 801, the signal from the transmission antenna 802 is not received. Can be received, the reception is not interrupted. Further, when the DVB-H receiving device 803 moves closer to the transmitting antenna 802, the DVB-H receiving device 803 receives only the channel of the frequency f2 transmitted from the transmitting antenna 802. The flow of these operations will be described with reference to FIGS. If the reception state deteriorates, it is considered that the normal service area boundary has been reached, so handover is performed. Since what kind of broadcasting is performed in the surrounding cells is known in advance by EPG (Electric Program Guide), NIT, channel search that is performed in advance, such as when power is turned on (specific operation will be explained later), these Based on the above information, a channel to be a handover candidate is determined at 501 in FIG. Next, the channel selection control unit 140 determines which of the first system 100 and the second system 101 in FIG. 1 is in a poor reception state, and as shown in 502 of FIG. To select a channel that is a candidate for handover, and the system with the better reception state continues receiving as it is. In 503, the channel selection control unit 140 in FIG. 1 determines whether or not the reception state is improved as a result. If bad, the process returns to 501 in FIG. 6, and if good, the channel of the handover candidate is received in 504. At this time, the system in which the reception state is good in 502 receives the channel before the handover as it is, but the channel is selected and received in each system as it is. By performing handover for each of the systems in this way, stable handover can be performed even if one of the signals cannot be received near the service area boundary.

  Next, the channel search operation performed when the power is turned on or when the receiving apparatus moves and exits from a long tunnel will be described with reference to FIGS. In the diversity receiver shown in FIG. 1, the second system 101 is not used, but the first system 100, the frame synthesis unit 130, the MPE-FECRS correction unit 131, and the back end receive and decode the transmission signal, and the program Information can be retrieved. Also, only the second system 101 can receive a broadcast signal, confirm the synchronization state, and measure C / N. Therefore, at the same time as confirming the broadcast of a certain channel in the first system, another channel is selected in the second system, and what transmission mode, guard interval, and C / N can receive the digital broadcast Can be confirmed. The channel search operation using this fact is shown in FIG. When the channel search is started, a channel is received at 402 using the first system 100 of FIG. 1 and the broadcast content is confirmed. At the same time, in 403 in FIG. 4, another channel is received using the second system 101 in FIG. 1, and using the synchronization state detection unit 127 and the C / N measurement unit 128, the transmission mode, Whether the signal can be received at the guard interval or C / N is detected, transmitted to the tuning control unit 140, and recorded in the memory 141. Returning to FIG. 4, the process returns to 402 and 403 until all channels are confirmed in 404, and all channels are confirmed. When these are completed, in 403, only the channel recorded as “digital broadcasting is being performed” is received and decoded, and the content of the broadcast is confirmed. In this way, the time required for all channel searches can be shortened.

  In FIG. 1, it is needless to say that the state of another channel can be confirmed in the second system 101 while receiving the broadcast in the first system 100.

  In FIG. 1, all or a part of each block excluding the antenna 110 and the antenna 120, or all the blocks excluding the tuner unit 111 and the tuner unit 121 in addition to the antenna 110 and the antenna 120 are typically integrated circuits. As realized. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation using a dedicated circuit, general-purpose processor, or DSP is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology and quantum technology can be applied.

(Embodiment 2)
FIG. 3 is a block diagram of a front end portion of the DVB-H receiving apparatus according to Embodiment 2 of the present invention. A description of a back end that performs decoding of video and audio signals, a video display device, an audio playback device, and the like will be omitted.

  The receiving apparatus shown in FIG. 3 has a first system 300 and a second system 301 that perform transmission signal selection and detection in order to perform diversity reception, and signals of channels that are independently selected in each system. Are combined by the carrier combining unit 330, error-corrected by the error correcting unit 331, and output to the back end.

  Next, the first system 300 will be described. An OFDM signal is received by the antenna 310, and a channel desired to be received by the tuner unit 311 is selected and down-converted. The channel to be selected is instructed from the channel selection control unit 340. The output of the tuner unit 311 is sent to the FFT unit 313 and the synchronization unit 312, and the FFT unit 313 performs Fourier transform to convert the signal from the time domain to the frequency domain. The output of the FFT unit 313 is also input to the synchronization unit 312 to perform time axis synchronization and frequency synchronization. The synchronization result in the synchronization unit 312 is sent to the synchronization state detection unit 315, and the type of the received signal (transmission mode, guard interval length, synchronization stability, etc.) is determined and sent to the channel selection control unit 340. Next, the signal converted into the frequency domain by the FFT unit 313 is sent to the detection unit 314 to perform detection processing. The signal being detected is sent to the C / N measurement unit 316, C / N is measured, and the result is sent to the channel selection control unit 340. The result detected by the detection unit 314 is output to the carrier synthesis unit 330 together with the C / N for each carrier measured by the C / N measurement unit 316.

  The second system 301 performs the same processing as the first system 300 as described below. The OFDM signal is received by the antenna 320, and the channel desired to be received by the tuner unit 321 is selected and down-converted. The channel to be selected is instructed from the channel selection control unit 340. The output of the tuner unit 321 is sent to the FFT unit 323 and the synchronization unit 322, and the FFT unit 323 performs Fourier transform to convert the signal from the time domain to the frequency domain. The output of the FFT unit 323 is also input to the synchronization unit 322 to perform time axis synchronization and frequency synchronization. The synchronization result in the synchronization unit 322 is sent to the synchronization state detection unit 325, and the type of the received signal (transmission mode, guard interval length, synchronization stability, etc.) is determined and sent to the channel selection control unit 340. Next, the signal converted into the frequency domain by the FFT unit 323 is sent to the detection unit 324 to perform detection processing. The signal being detected is sent to the C / N measurement unit 326, C / N is measured, and the result is sent to the channel selection control unit 340. The result detected by the detection unit 324 is output to the carrier synthesis unit 330 together with the C / N for each carrier measured by the C / N measurement unit 326.

  The channel selection control unit 340 receives the outputs of the synchronization state detection unit 315, the C / N measurement unit 316 of the first system 300, the synchronization state detection unit 325 of the second system 301, and the C / N measurement unit 326, and the memory unit 341 records and reads information on each channel, determines the channel to be received by the first system 300 and the second system 301, sends a channel selection signal to the tuner unit 311 and the tuner unit 321, and sets the channel. Switch.

  The carrier synthesizing unit 330 synthesizes the signals output from the first system 300 and the second system 301 based on the C / N measurement results for each carrier.

  In the second embodiment, as in the first embodiment, a stable handover operation is performed, a channel search is performed in a short time, and the reception status of other channels in the second system is being received in the first system. Needless to say, it can be confirmed.

  In FIG. 3, all or a part of each block excluding the antenna 310 and the antenna 320, or all the blocks excluding the tuner unit 311 and the tuner unit 321 in addition to the antenna 310 and the antenna 320 are typically integrated circuits. As realized. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation using a dedicated circuit, general-purpose processor, or DSP is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology and quantum technology can be applied.

  The technique for performing a stable handover according to the present invention can be applied to a terminal that receives an OFDM signal.

Block diagram showing Embodiment 1 of the present invention Block diagram showing conventional diversity reception The block diagram which shows Embodiment 2 of this invention The flowchart which shows the procedure of the channel search of this invention A flowchart showing a conventional channel search procedure The flowchart which shows the procedure of the hand-over of this invention A flowchart showing a conventional handover procedure The figure which shows the receiving environment of this invention A diagram showing a conventional frequency diversity reception environment The figure which shows the case where there is a shield in the conventional frequency diversity reception environment

Explanation of symbols

100 first system 101 second system 110 antenna 111 tuner unit 112 synchronization unit 113 FFT unit 114 detection unit 115 error correction unit 116 CRC check unit 117 synchronization state detection unit 118 C / N measurement unit 120 antenna 121 tuner unit 122 synchronization Unit 123 FFT unit 124 detection unit 125 error correction unit 126 CRC check unit 127 synchronization state detection unit 128 C / N measurement unit 130 frame synthesis unit 131 MPE-FECRS correction unit 140 channel selection control unit 141 memory unit 201 first system 205 Detection unit 206 Carrier synthesis unit 207 Error correction unit 211 Second system 215 Detection unit 300 First system 301 Second system 310 Antenna 311 Tuner unit 312 Synchronization unit 313 FFT unit 314 Detection unit 315 Synchronization state detection unit 316 C / N measurement Unit 320 antenna 321 tuner unit 322 synchronization unit 323 FFT unit 324 detection unit 325 synchronization state detection unit 326 C / N measurement unit 330 carrier synthesis unit 331 error correction unit 401 search procedure 402 first system search procedure 403 second system search Procedure 404 All channel confirmation determination procedure 405 Recording channel confirmation procedure 501 Candidate channel determination procedure 502 Channel selection procedure 503 Reception state determination procedure 504 Handover determination procedure 801 Transmitting antenna 802 Transmitting antenna 803 Receiver 804 Shielding object 901 Transmitting antenna 903 Receiver 904 Shielding object

Claims (18)

A receiving device that receives digital signals transmitted at different frequencies in adjacent areas,
A plurality of antennas for receiving the digital signals;
A plurality of channel selection means for selecting a digital signal of a desired frequency from each received digital signal;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of reception quality detection means for detecting reception quality of each demodulated signal;
A receiving apparatus comprising: a channel selection control unit that independently changes a frequency selected by a plurality of channel selection units in accordance with each reception quality detected by the plurality of reception quality detection units. The receiving device according to claim 1, wherein outputs from the plurality of demodulation means are combined and output. A receiving device for receiving a digital signal encoded by combining error detection codes,
A plurality of antennas for receiving the digital signals;
A plurality of channel selection means for selecting a digital signal of a desired frequency from each received digital signal;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of error detection means for detecting an error of each demodulated digital signal;
A selection means for preferentially selecting and outputting a digital signal confirmed to be error-free from the outputs of the plurality of demodulation means as a result of the error detection;
A receiving device that receives digital signals transmitted at a plurality of frequencies and preferentially selects and outputs a signal in which no error is detected. Further comprising error correction means for correcting and outputting the selectively output signal;
4. The receiving apparatus according to claim 3, wherein a signal obtained by preferentially selecting a signal in which no error is detected is error-corrected and output. A receiving device that receives digital signals transmitted at different frequencies in adjacent areas,
A plurality of antennas for receiving the digital signals;
A plurality of channel selection means for selecting a digital signal of a necessary frequency from each received digital signal;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of reception state detection means for detecting reception states of the demodulated signals;
Storage means for storing each detected reception state;
Channel selection control means for determining a plurality of frequencies to be selected by the plurality of channel selection means according to the plurality of stored reception states,
A receiving apparatus in which each of the plurality of channel selecting means independently selects a plurality of frequencies and confirms a plurality of reception states. While receiving digital signals transmitted at the first frequency, select multiple frequencies using some antennas, some channel selection means, some demodulation means, and some reception status detection means. 6. The receiving apparatus according to claim 5, wherein a plurality of receiving states are confirmed. The receiving apparatus according to claim 5, wherein the reception state is C / N, and the reception state detection unit is a C / N detection unit. The receiving apparatus according to claim 5, wherein the reception state is a synchronization state, and the reception state detection unit is a synchronization detection unit. The receiving apparatus according to claim 5 or 6, wherein the reception state is a synchronization state and C / N, and the reception state detection unit is a synchronization detection unit and a C / N detection unit. An integrated circuit of a device for receiving digital signals transmitted at different frequencies in adjacent areas,
A plurality of channel selection means for selecting a digital signal of a desired frequency from each of the digital signals;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of reception quality detection means for detecting reception quality of each demodulated signal;
An integrated circuit comprising: a channel selection control unit that independently changes a frequency selected by a plurality of channel selection units in accordance with each reception quality detected by the plurality of reception quality detection units. The integrated circuit according to claim 10, wherein the outputs from the plurality of demodulation means are combined and output. An integrated circuit of an apparatus for receiving a digital signal encoded by combining error detection codes,
A plurality of channel selection means for selecting a digital signal of a desired frequency from each of the digital signals;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of error detection means for detecting an error of each demodulated digital signal;
A selection means for preferentially selecting and outputting a digital signal confirmed to be error-free from the outputs of the plurality of demodulation means as a result of the error detection;
An integrated circuit that receives digital signals transmitted at a plurality of frequencies and preferentially selects and outputs signals for which no error has been detected. Further comprising error correction means for correcting and outputting the selectively output signal;
13. The integrated circuit according to claim 12, wherein a signal in which a signal in which no error is detected is preferentially selected is error-corrected and output. An integrated circuit of a device for receiving digital signals transmitted at different frequencies in adjacent areas,
A plurality of channel selection means for selecting a digital signal having a required frequency from each of the digital signals;
A plurality of demodulation means for demodulating each of the selected digital signals;
A plurality of reception state detection means for detecting reception states of the demodulated signals;
Storage means for storing the respective detected reception states;
Channel selection control means for determining a plurality of frequencies to be selected by the plurality of channel selection means according to the plurality of stored reception states,
An integrated circuit in which each of the plurality of channel selecting means independently selects a plurality of frequencies and confirms a plurality of reception states. While receiving digital signals transmitted at the first frequency, select multiple frequencies using some antennas, some channel selection means, some demodulation means, and some reception status detection means. 15. The integrated circuit according to claim 14, wherein a plurality of reception states are confirmed. 16. The integrated circuit according to claim 14, wherein the reception state is C / N, and the reception state detection unit is a C / N detection unit. 16. The integrated circuit according to claim 14, wherein the reception state is a synchronization state, and the reception state detection unit is a synchronization detection unit. 16. The integrated circuit according to claim 14, wherein the reception state is a synchronization state and C / N, and the reception state detection unit is a synchronization detection unit and a C / N detection unit.

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