JP2009033497A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver which arranges a receiving antenna relatively near a disturbance source to cancel a disturbance signal mixed in the receiving antenna and does not deteriorate a receiving performance even when a receiving radio wave intensity is low. <P>SOLUTION: The receiver has a synthesis portion 112 which has a plurality of branches of a receiving antenna 101, and a demodulator, to synthesize output signals of the plural branches for diversity reception. The receiver further has, in the receiver having a signal processor 113 which receives output signals of the synthesis portion 112 and conducts demodulation and error correction, a detecting antenna 105 other than the receiving antenna 101 for receiving radio waves as disturbance signals; an adjustor 108 which inputs the disturbance signal received and converted by the detecting antenna 105, adjusts a gain, a delay and a phase and outputs an adjustment disturbance signal; and a subtractor 109 which subtracts the adjustment disturbance signal from a receiving signal of the branch of the diversity reception. The receiver inputs the output signal of the subtractor 109 into the demodulator 111. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives a digital broadcast, and more particularly to a receiving apparatus in which a radio wave interference source and a receiving antenna are arranged relatively close to each other, such as an in-vehicle, a personal computer, a mobile phone, and an antenna built-in television.

  Japan's terrestrial digital television broadcast (hereinafter abbreviated as ISDB-T broadcast) started on December 1, 2003 in Tomei Osaka. ISDB-T broadcasting uses OFDM (Orthogonal frequency division multiplexing), which is a type of multicarrier modulation, and is resistant to multipath. In addition, since frequency interleaving and time interleaving are applied, it is relatively easy for indoor reception. strong. Furthermore, it is also possible to select a parameter that is strong against transmission distortion using a mobile layer and a mobile layer, and a modulation scheme and error correction coding rate. For this reason, indoor reception by an indoor antenna for ISDB-T broadcasting is expected, and an antenna for indoor reception and an indoor receiver are being studied.

  In indoor reception, multipath generally occurs due to indoor reflection, and diversity reception is effective. In spatial diversity, a plurality of antennas are placed away from each other to such an extent that signal fluctuations are uncorrelated, and outputs are selected or combined. As synthesis methods, (1) selective synthesis method, (2) equal gain synthesis method, and (3) maximum ratio synthesis method are known. The selective combining method is a method of selecting and switching the branch having the highest reception level (or the best C / N), and the equal gain combining method is after adjusting the phase so that the phases between the branches are in phase. The maximum ratio combining method is a method of adjusting both the amplitude and the phase to obtain an output with the maximum C / N. The diversity method is shown in Non-Patent Document 1.

Further, Patent Document 1 discloses a method of using diversity when receiving an OFDM system adopted by ISDB-T broadcasting. This receives an OFDM signal, converts this received signal from the time domain to the frequency domain, extracts the signal for each carrier, demodulates the signal data assigned to each carrier, and obtains the demodulated data for each carrier obtained. This is a method of performing diversity combining processing in units of carriers.
Japanese Patent No. 3389178 Corona: Yoshio Karasawa “Radio Propagation Fundamentals for Digital Mobile Communications” First Edition, March 17, 2003

In the case of a personal computer or indoor reception television, the receiving antenna is built in the receiver body or placed near it. In addition, a receiving antenna is attached to the car for in-vehicle reception.
In general, a personal computer, a mobile phone, a TV main body, a car, and the like radiate an interference signal that impedes reception radio waves. Interfering signals include leakage of clock signals on personal computers and mobile phones, leakage of signals from display drive circuits such as liquid crystal and plasma and digital signal processing boards from the TV body, and leakage of signals from engines and other electrical devices from cars. And so on.

  The interference signal is picked up by the reception antenna together with the necessary reception signal and is superimposed on the necessary reception signal, and there is a problem that the reception performance is greatly affected particularly when the reception radio wave intensity is low. Since indoors are via walls and windows, the received radio wave strength is often low.

  In the receiving apparatus of the present invention, an interference signal detection antenna for detecting an interference signal is installed near the interference source, thereby detecting the interference signal, and using the detected interference signal using at least one of gain, delay, and phase. The adjustment is performed, the interference signal mixed in the reception antenna is canceled, and the necessary reception signal is extracted. The technical idea described in the claims may be used.

  According to the present invention, since the interference signal mixed in the reception antenna can be canceled, the reception antenna can be disposed relatively close to the interference source, and the reception performance can be improved even when the reception radio wave intensity is low. Has the effect of not deteriorating.

The best mode for carrying out the present invention will be described.
The present invention has a plurality of branches each including a receiving antenna and a demodulating unit, combines a signal output from the plurality of branches to receive diversity, inputs an output signal from the combining unit, and performs decoding and error correction. In a receiving apparatus having a signal processing unit, a detection antenna that receives a radio wave that becomes a disturbing signal, different from the receiving antenna, and a disturbing signal that is received and converted by the detecting antenna are input, and gain, delay, and phase are input. At least one adjustment unit that adjusts at least one and outputs an adjustment interference signal; and at least one subtraction unit that subtracts the adjustment interference signal from a reception signal of at least one branch of the diversity reception, the subtraction unit This is a receiving device that inputs the output signal to the demodulator.
Hereinafter, embodiments of the present invention will be described by taking a small television receiver for indoor reception of ISDB-T broadcasting as an example.

Example 1 will be described. FIG. 1 is a block diagram showing a configuration of a two-branch spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention.
101, 102 are reception antennas, 103, 104, 106 are channel selection units, 105 is an interference signal detection antenna, 107 is a local oscillation unit, 108 is a gain / delay / phase adjustment unit, 109 is a subtraction unit, 110, 111 are The demodulating unit, 112 is a combining unit, 113 is a decoding / error correcting unit, and 114 is an output.

The receiving antennas 101 and 102 are installed, for example, at the upper left and right ends of a small television so that the ISDB-T broadcast can be received with as little correlation as possible. The interfering signal detecting antenna 105 is attached at a position that receives only the interfering signal without receiving the ISDB-T broadcast as much as possible.
A channel selection channel band required by the channel selection unit 103 is extracted from the reception signal received by the reception antenna 101 and demodulated by the demodulation unit 110. At the same time, the channel selection unit 104 extracts the same necessary channel selection band as the channel selection unit 103 from the received signal received by the reception antenna 102.

On the other hand, the channel selection unit 106 extracts the same channel selection band as the channel selection unit 103 from the interference signal received by the interference signal detection antenna 105. The extracted interference signal is adjusted in gain, delay, and phase by the adjustment unit 108 and output to the subtraction unit 109. The subtraction unit 109 subtracts the output signal of the adjustment unit 108 from the output signal of the channel selection unit 104, and the output signal of the subtraction unit 109 is demodulated by the demodulation unit 111.
The synthesizer 112 synthesizes the output signals of these demodulator units 110 and 111.
The combined signal is decoded by the decoding / error correction unit 113 and subjected to error correction, and output to the output unit 114.
The channel selection units 104 and 106 perform a channel selection operation using the signal from the local oscillation unit 107 as a reference signal.

  The effect of the embodiment of FIG. 1 will be described with reference to FIG. FIG. 2 shows the frequency spectrum of the output signals of the channel selection units 103, 104, and 106 and the subtraction unit 109. (A) is an output signal of the channel selection unit 103, 201 is a necessary channel channel band signal spectrum received by the reception antenna 101, and 203 is an interference signal spectrum of the channel selection channel band mixed in the reception antenna 101. (B) is an output signal of the channel selection unit 104, 202 is a necessary channel channel band signal spectrum received by the receiving antenna 102, and 204 is an interference signal spectrum of the channel selection channel band mixed in the receiving antenna 102. (C) is an output signal of the channel selection unit 106, 205 is an interference signal spectrum extracted in the channel selection channel band, (d) is an output signal of the subtraction unit 109, and 206 is received by the receiving antenna 102 after the subtraction. It is a necessary channel selection channel band signal spectrum.

In the example of FIG. 2, the interference signal exists in the entire selected channel band.
Originally, the spectrum of an ISDB-T broadcast signal is almost rectangular within the channel selection band. The spectra 201 and 202 are shown in an example that is somewhat affected by multipath. Since the receiving antennas 101 and 102 are arranged with as little correlation as possible, the shapes of the spectra 201 and 202 are also different.

In the embodiment of FIG. 1, the adjustment unit 108 adjusts the interference signal spectrum 205 to the same gain / delay / phase as the interference signal spectrum 204 and subtracts it by the subtraction unit 109 to remove the interference signal, and the necessary channel selection channel. A spectrum 206 of only the band signal is obtained.
The demodulation units 110 and 111 demodulate the output signal of the channel selection unit 103 in FIG. 2A and the output signal of the subtraction unit 109 in FIG. 2D, respectively, into baseband signals, and perform FFT (Fast Fourier Transform). Convert from time axis to frequency axis. The combining unit 112 performs, for example, maximum ratio combining for each carrier of the output signals on the frequency axis of the demodulation units 110 and 111. The interference signal is removed from the output signal of the subtracting unit 109, and a good C / N state can be expected. However, due to the reception status at the receiving antennas 101 and 102 and the influence of multipath, the output signal of the tuning unit 103 is In some cases, there may be a carrier having a better C / N.

  FIG. 3 shows an example in which an interference signal exists only in a part of the channel selection channel band. The same reference numerals as those in FIG. 2 represent the same spectrum, (a) is an output signal of the channel selection unit 103, and 301 is an interference signal spectrum of the channel selection band mixed in the reception antenna 101. (B) is an output signal of the tuning unit 104, and 302 is an interference signal spectrum of the tuning channel band mixed in the receiving antenna. (C) is an output signal of the channel selection unit 106, 303 is an interference signal spectrum extracted in the channel selection channel band, and (d) is an output signal of the subtraction unit 109.

  In the case of FIG. 3, similarly to the case of FIG. 2, the interference signal spectrum 303 is adjusted to the same gain / delay / phase as the interference signal spectrum 302 by the adjustment unit 108 and subtraction is performed by the subtraction unit 109 to remove the interference signal. The spectrum 206 of only the necessary channel-band signal is obtained. When the band is narrow or when the interference signal is a carrier signal, the adjustment unit 108 can be expected to have an interference removal effect only by gain / phase adjustment without delay adjustment.

  FIG. 4 shows an example in which not only the interference signal but also the ISDB-T broadcast signal is received by the interference detection antenna 105 with respect to the example of FIG. The same reference numerals as those in FIG. 3 represent the same spectrum, (a) is an output signal of the channel selection unit 103, and (b) is an output signal of the channel selection unit 104. (C) is an output signal of the channel selection unit 106, 401 is a channel selection channel band spectrum of the ISDB-T broadcast signal received by the interference detection antenna 105, and (d) is an output signal of the subtraction unit 109. Reference numeral 402 denotes a necessary channel-band signal spectrum received by the receiving antenna 102 after subtraction.

  Although the interference detection antenna 105 is intended to detect only the interference signal, it may actually receive an ISDB-T broadcast signal. In this case, the interference signal can be removed by the subtraction process, but the necessary channel-band signal spectrum 402 is also affected. This degree indicates the correlation between the necessary channel-band signal spectrum 202 received by the receiving antenna 102 and the channel-band signal spectrum 401 of the ISDB-T broadcast signal received by the interference detection antenna 105, and the reception. The combining ratio in the combining unit 112 is determined by the size of the interference signal spectrum 301 in the selected channel band mixed in the antenna 101. In general, it can be expected that the band where the interference signal exists is improved in C / N.

  According to the receiving apparatus of FIG. 1, since the subtraction processing for interference removal is performed in the IF (intermediate frequency) band after channel selection, the necessary frequency characteristics of the adjustment unit 108 and the subtraction unit 109 are the channel selection channels in the IF band. Only the band is sufficient, and the channel selection units 103, 104, and 106 generally perform automatic gain control, so that the dynamic range required for the adjustment unit 108 and the subtraction unit 109 can be reduced.

  Further, since the channel selection operation of the channel selection units 104 and 106 uses the common signal from the local oscillation unit 107 as a reference signal, the IFs of the channel selection units completely match, and the IF of the subtraction processing unit 109 is There is an effect which does not cause deterioration of the interference removal effect due to the difference. Note that the channel selection operation of the channel selection unit 103 may be performed with reference to a common signal from the local oscillation unit 107, but normally, the demodulation units 110 and 111 and the channel selection unit 104 (channel selection unit 106). ) Is absorbed.

A second embodiment will be described. FIG. 5 is another block diagram showing a configuration of a two-branch spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1 denote the same functions, 501 is a gain / delay / phase adjustment unit, 502 is a subtraction unit, and 503 and 504 are channel selection units.
The embodiment of FIG. 5 is performed in the transmission frequency band of ISDB-T broadcasting, whereas the embodiment of FIG. 1 performs interference removal in the IF band.
A channel selection channel band required by the channel selection unit 103 is extracted from the reception signal received by the reception antenna 101 and demodulated by the demodulation unit 110.

  On the other hand, the interference signal received by the interference signal detection antenna 105 is adjusted in gain, delay, and phase by the adjustment unit 501 and output to the subtraction unit 502. At the same time, the received signal received by the receiving antenna 102 is output to the subtracting unit 502, and the subtracting unit 502 subtracts the output signal from the adjusting unit 501 from the received signal received by the receiving antenna 102 to remove the interference signal. The output signal of the subtraction unit 502 is output to the channel selection unit 503. The channel selection unit 503 extracts the same necessary channel selection band as that of the channel selection unit 103, and is demodulated by the demodulation unit 111.

  According to the receiving apparatus of FIG. 5, since the subtraction processing for interference removal is performed in the transmission frequency band, there is an effect that the tuning unit for the interference signal detection antenna 105 is not necessary.

A third embodiment will be described. FIG. 6 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. The same symbols as those in FIG. 1 represent the same function, 601 is a channel selection unit, 602 is a gain / delay / phase adjustment unit, and 603 is a subtraction unit.
In the present embodiment, the interference removal processing is performed only on the reception antenna 101 side, whereas the embodiment of FIG. 1 performs the interference removal processing only on the reception signal on the reception antenna 102 side.
A channel selection channel band required by the channel selection unit 601 is extracted from the reception signal received by the reception antenna 101. At the same time, the channel selection unit 104 extracts the same necessary channel selection band as that of the channel selection unit 601 from the reception signal received by the reception antenna 102.
On the other hand, the channel selection unit 106 extracts the same channel selection band as that of the channel selection unit 103 from the interference signal received by the interference signal detection antenna 105. The extracted interference signals are adjusted in gain, delay, and phase by adjusting units 602 and 108, and output to subtracting units 603 and 109, respectively. The subtraction unit 603 subtracts the output signal of the adjustment unit 602 from the output signal of the channel selection unit 601, and the output signal of the subtraction unit 603 is demodulated by the demodulation unit 110. At the same time, the subtraction unit 109 subtracts the output signal of the adjustment unit 108 from the output signal of the channel selection unit 104, and the output signal of the subtraction unit 109 is demodulated by the demodulation unit 111.
The synthesizer 112 synthesizes the output signals of these demodulator units 110 and 111.
The synthesized signal is decoded by the decoding / error correction unit 113 and subjected to error correction, and is output to the output unit 114.
Note that the channel selection units 601, 104, and 106 perform a channel selection operation using the signal from the local oscillation unit 107 as a reference signal.

The effect of the embodiment of FIG. 6 will be described with reference to FIG. FIG. 7 shows the frequency spectrum of the output signals of the channel selection units 601, 104, and 106 and the subtraction units 603 and 109. The same reference numerals as those in FIG. 2 represent the same spectrum.
(A) is an output signal of the channel selection unit 601, (b) is an output signal of the channel selection unit 104, (c) is an output signal of the channel selection unit 106, and (d) is an output signal of the subtraction unit 109. (E) is an output signal of the subtraction unit 603, and 701 is a necessary channel-band signal spectrum received by the receiving antenna 101 after subtraction.

In the example of FIG. 7, the interference signal exists in the entire channel selection channel band.
In the embodiment of FIG. 6, the adjustment unit 108 adjusts the interference signal spectrum 205 to the same gain / delay / phase as the interference signal spectrum 204, and subtracts it by the subtraction unit 109 to remove the interference signal, and the necessary channel selection channel. The spectrum 206 of only the band signal is obtained, the interference signal spectrum 205 is adjusted to the same gain / delay / phase as the interference signal spectrum 203 by the adjustment unit 602, and the interference signal is removed by subtraction by the subtraction unit 603. A spectrum 701 of only the selected channel band signal is obtained.
The demodulating units 110 and 111 demodulate the output signal of the subtracting unit 603 in FIG. 7E and the output signal of the subtracting unit 109 in FIG. 7D, respectively, into baseband signals, and perform FFT (Fast Fourier Transform). Convert from time axis to frequency axis. The combining unit 112 performs, for example, maximum ratio combining for each carrier of the output signals on the frequency axis of the demodulation units 110 and 111. Interference signals are removed from the output signals of the subtraction units 603 and 104, respectively, and a diversity effect equivalent to the case where no interference signals are mixed can be expected.
According to the receiving apparatus of FIG. 6, compared with the embodiment of the receiving apparatus of FIG. 1, the interference signal can be removed from the reception signals of the reception antennas 101 and 102.

  Example 4 will be described. FIG. 8 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1 and 5 indicate the same function, 801 is a gain / delay / phase adjustment unit, and 802 is a subtraction unit.

The embodiment of FIG. 8 is performed in the transmission frequency band of ISDB-T broadcasting, whereas the embodiment of FIG. 6 performs interference removal in the IF band.
The interference signal received by the interference signal detecting antenna 105 is adjusted in gain, delay, and phase by the adjustment units 801 and 501 and output to the subtraction units 802 and 502, respectively. At the same time, the reception signals received by the reception antennas 101 and 102 are output to the subtraction units 802 and 502, respectively, and the subtraction unit 802 subtracts the output signal from the adjustment unit 801 from the reception signal received by the reception antenna 101. The subtraction unit 502 subtracts the output signal from the adjustment unit 501 from the reception signal received by the reception antenna 102, and removes the interference signal.
The output signals of the subtraction units 802 and 502 are output to the channel selection units 103 and 503, respectively. The channel selection unit 103 and the channel selection unit 503 extract the same necessary channel selection channel band, and the demodulation units 110 and 111 respectively demodulate.

  According to the receiving apparatus of FIG. 8, compared with the receiving apparatus of FIG. 6, since the subtraction processing for interference removal is performed in the transmission frequency band, there is an effect that the channel selection unit for the interference signal detecting antenna 105 is unnecessary. is there.

  Example 5 will be described. FIG. 9 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1 and 6 represent the same function, 901 is an interference signal detection antenna, 902 is a channel selection unit, and 903 is a local signal generation unit.

The embodiment of FIG. 9 has two interference signal detection antennas 105 and 901 corresponding to two interference sources.
Interference signal detection antenna 105, reception antenna 102, channel selection units 104 and 106, adjustment unit 108, subtraction unit 109, local oscillation unit 107, interference signal detection antenna 901, reception antenna 101, channel selection units 604 and 902, The system of the adjustment unit 602, the subtraction unit 603, and the local oscillation unit 903 removes the interference signal by the same operation.
The effect of the embodiment of FIG. 9 will be described with reference to FIG. FIG. 10 shows the frequency spectrum of the output signals of the channel selection units 601, 104, 902 and 106 and the subtraction units 603 and 109. 2 and 3 indicate the same spectrum.
(A) is an output signal of the channel selection unit 601, (b) is an output signal of the channel selection unit 104, (c) is an output signal of the channel selection unit 902, (d) is an output signal of the channel selection unit 106, and (e) is a subtraction unit. An output signal of 603, (f) is an output signal of the subtractor 109.
Interference signal spectrums 301, 302, and 303 are interference signals from the interference source 1 in which the interference signal detection antenna 105 is installed. The interference signal spectrums 1001, 1002, and 1003 are interference signals from the interference source 2 in which the interference signal detection antenna 901 is installed.
In the subtraction unit 603, only the interference signal 1001 from the interference source 2 is removed by adjusting the interference signal 1003 by the adjustment unit 602. Further, in the subtraction unit 109, only the interference signal 302 from the interference source 1 is removed by adjusting the interference signal 303 by the adjustment unit 108.
Each of the demodulation units 110 and 111 demodulates the output signal of the subtraction unit 603 in FIG. 10E and the output signal of the subtraction unit 109 in FIG. 10F to form a baseband signal, and performs FFT (Fast Fourier Transform). Convert from time axis to frequency axis. The combining unit 112 performs, for example, maximum ratio combining for each carrier of the output signals on the frequency axis of the demodulation units 110 and 111.
Interference signals 301 and 1002 remain in the output signals of the subtracting units 603 and 109, respectively. However, since the bands are different, it can be expected that the synthesizing unit 112 synthesizes the entire band with a good C / N.
According to the receiving apparatus of FIG. 9, there is an effect that the interference removal capability is high with respect to interference signals from two interference sources, particularly in different bands.

Example 6 will be described. FIG. 11 is another block diagram showing the configuration of a two-branch spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1, 5, 8, and 9 represent the same function.
The embodiment of FIG. 11 is performed in the transmission frequency band of ISDB-T broadcasting, whereas the embodiment of FIG. 9 performs interference removal in the IF band.
The interference signals received by the interference signal detection antennas 901 and 105 are adjusted in gain, delay, and phase by the adjustment units 801 and 501, respectively, and output to the subtraction units 802 and 502, respectively. At the same time, the reception signals received by the reception antennas 101 and 102 are output to the subtraction units 802 and 502, respectively, and the subtraction unit 802 subtracts the output signal from the adjustment unit 801 from the reception signal received by the reception antenna 101. The subtraction unit 502 subtracts the output signal from the adjustment unit 501 from the reception signal received by the reception antenna 102, and removes the interference signal.
The output signals of the subtraction units 802 and 502 are output to the channel selection units 103 and 503, respectively. The channel selection unit 103 and the channel selection unit 503 extract the same necessary channel selection channel band, and the demodulation units 110 and 111 respectively demodulate.

  According to the receiving apparatus of FIG. 11, since the subtraction processing for interference removal is performed in the transmission frequency band as compared with the receiving apparatus of FIG. 9, the tuning unit for the interference signal detecting antennas 901 and 105 becomes unnecessary. effective.

Example 7 will be described. FIG. 12 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1 and 9 represent the same function, 1201 is a tuning unit, 1202 is a gain / delay / phase adjustment unit, and 1203 is a subtraction unit.
The embodiment of FIG. 12 has two interference signal detection antennas 105 and 901 corresponding to two interference sources.
The interference signal detection antenna 105, the receiving antenna 102, the channel selection units 104 and 106, the adjustment unit 108, the subtraction unit 109, and the local oscillation unit 107 are used to remove interference at one location, and then further to the interference signal detection antenna 901 and the selection unit. The local part 1201, the adjustment part 1202, and the subtraction part 1203 remove the second interference. Note that the channel selection unit 1201 also performs a channel selection operation using the signal from the local oscillation unit 107 as a reference signal, similarly to the channel selection units 104 and 106.
The effect of the embodiment of FIG. 12 will be described with reference to FIG. FIG. 13 shows the frequency spectrum of the output signals of the channel selection units 103, 104, 106, 1201, and the subtraction units 109, 1203. 2 and 10 indicate the same spectrum.
(A) is an output signal of the channel selection unit 103, (b) is an output signal of the channel selection unit 104, (c) is an output signal of the channel selection unit 106, (d) is an output signal of the channel selection unit 1201, and (e) is a subtraction unit. 109 is an output signal, (f) is an output signal of the subtractor 1203, and 1301 is a necessary channel-band signal spectrum received by the receiving antenna 102 after the subtraction.
The interference signal spectrums 203, 204, and 205 are interference signals from the interference source 1 in which the interference signal detection antenna 105 is installed. The interference signal spectrums 1001, 1002, and 1003 are interference signals from the interference source 2 in which the interference signal detection antenna 901 is installed.
In the subtractor 109, as shown in FIG. 13E, only the interference signal 204 from the interference source 1 is removed by adjusting the interference signal 205 by the adjustment unit 108. Next, in the subtraction unit 1203, as shown in FIG. 13 (f), the interference signal 1002 from the interference source 2 is also removed by adjusting the interference signal 1003 by the adjustment unit 1202, and as a result, both of the interference sources 1 and 2 are removed. Interfering signals are removed.
Each of the demodulation units 110 and 111 demodulates the output signal of the channel selection unit 103 in FIG. 2A and the output signal of the subtraction unit 1203 in FIG. 13F to form a baseband signal by FFT (Fast Fourier Transform). Convert from time axis to frequency axis. The combining unit 112 performs, for example, maximum ratio combining for each carrier of the output signals on the frequency axis of the demodulation units 110 and 111. The interference signal is removed from the output signal of the subtraction unit 1203, and a good C / N state can be expected. However, the output signal of the channel selection unit 103 is affected by the reception status at the reception antennas 101 and 102 and the influence of multipath. In some cases, there may be a carrier having a better C / N.
According to the receiving apparatus of FIG. 13, there is an effect that the interference removal capability is high with respect to the interference signals from the two interference sources.
Note that the technique of having a plurality of subtracting units in one branch in series in FIG. 12 can also be applied to the embodiments in FIGS.

Example 8 will be described. FIG. 14 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1, 5, and 9 represent the same function, 1401 is a gain / delay / phase adjustment unit, and 1402 is a subtraction unit.
The embodiment of FIG. 14 is performed in the transmission frequency band of ISDB-T broadcasting, whereas the embodiment of FIG. 12 performs interference removal in the IF band.
The interference signals received by the interference signal detection antennas 105 and 901 are adjusted in gain, delay, and phase by the adjustment units 501 and 1401, respectively, and output to the subtraction units 502 and 1402, respectively.
The reception signal received by the reception antenna 102 is output to the subtraction unit 502, and the subtraction unit 502 subtracts the output signal from the adjustment unit 501 from the reception signal received by the reception antenna 102 to remove interference at one place, and then the subtraction unit. The subtraction unit 1402 subtracts the output signal from the adjustment unit 1401 and further removes the second interference.
The output signal of the subtraction unit 1402 is output to the channel selection unit 503. At the same time, the reception signal received by the reception antenna 101 is output to the channel selection unit 103. The channel selection unit 103 and the channel selection unit 503 extract the same necessary channel selection channel band, and the demodulation units 110 and 111 respectively demodulate.
According to the receiving apparatus in FIG. 14, as compared with the receiving apparatus in FIG. 12, the subtraction processing for interference removal is performed in the transmission frequency band, so that the tuning unit for the interference signal detection antennas 901 and 105 is not necessary. effective.

Note that the technique of having a plurality of subtracting units in one branch in series in FIG. 14 can also be applied to the embodiments in FIGS.
Further, in FIGS. 1, 6, 9, and 12, interference removal by subtraction processing is performed in the intermediate frequency band, but it is also possible to perform it in the demodulated baseband band.

Example 9 will be described. FIG. 15 is another block diagram showing a configuration of a two-branch type spatial diversity receiving apparatus using two receiving antennas according to an embodiment of the present invention. 1, 5, and 8 indicate the same function, 1501 is a signal processing unit including demodulation units 110 and 111, a combining unit 112, and a decoding / error correction unit 113, and 1502 is a control unit. .
The embodiment of FIG. 15 shows a configuration for automatically adjusting the gain, delay, and phase of the adjusting units 501 and 801 of the embodiment of FIG.
An index indicating the C / N of the input signal of the demodulator 110 detected by the demodulator 110 and the degree of distortion (Modulation Error Rate (MER) indicating the spread of the constellation) detected by the demodulator 110 from the signal processor 1501, and detected by the demodulator 111 The information indicating the C / N of the input signal of the demodulator 110 and the index indicating the degree of distortion and the error rate detected by the decoding / error correction unit 113 are output to the control unit 1502. The control unit 1502 adjusts the adjustment unit 801 so that the index on the demodulation unit 110 side is the best, adjusts the adjustment unit 501 so that the index on the demodulation unit 111 side is the best, and adjusts so that the error rate is the best. The parts 801 and 501 are adjusted.
In the embodiment of FIG. 15, gain, delay, and phase are automatically controlled, and there is an effect that an optimal diversity effect can be obtained.
Note that the automatic adjustment of the adjustment unit of the embodiment of FIG. 15 can also be applied to the embodiments of FIGS. 1, 5, 6, 8, 8, 9, and 14.

  The present invention is applicable not only to indoor reception of ISDB-T broadcasts but also to indoor reception of all transmission signals. In addition, not only indoors but also any places such as automobiles, trains, ships, etc., as long as the receiving antenna is arranged near the interference source.

FIG. 2 is a block diagram illustrating a configuration of a receiving apparatus according to the first embodiment. FIG. 6 is a spectrum diagram for explaining the operation of the receiving apparatus according to the first embodiment. FIG. 6 is another spectrum diagram for explaining the operation of the receiving apparatus according to the first embodiment. FIG. 6 is still another spectrum diagram for explaining the operation of the receiving apparatus according to the first embodiment. FIG. 4 is a block diagram illustrating a configuration of a receiving apparatus according to a second embodiment. FIG. 6 is a block diagram illustrating a configuration of a receiving device according to a third embodiment. FIG. 7 is a spectrum diagram for explaining the operation of the receiving apparatus according to the third embodiment. FIG. 9 is a block diagram illustrating a configuration of a receiving device according to a fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a receiving apparatus according to a fifth embodiment. FIG. 7 is a spectrum diagram for explaining the operation of the receiving apparatus according to the fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a receiving apparatus according to a sixth embodiment. FIG. 10 is a block diagram illustrating a configuration of a receiving device according to a seventh embodiment. FIG. 11 is a spectrum diagram for explaining the operation of the receiving apparatus according to the seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a receiving apparatus according to an eighth embodiment. FIG. 10 is a block diagram illustrating a configuration of a receiving device according to a ninth embodiment.

Explanation of symbols

101, 102 Reception antenna 103, 104, 106 Channel selection unit 105 Interference signal detection antenna 107 Local oscillation unit 108 Gain / delay / phase adjustment unit 109 Subtraction unit 110, 111 Demodulation unit 112 Combining unit 113 Decoding / error correction unit 114 Output 501 Gain / Delay / Phase Adjustment Unit 502 Subtraction Units 503 and 504 Channel Selection Unit 601 Channel Selection Unit 602 Gain / Delay / Phase Adjustment Unit 603 Subtraction Unit 801 Gain / Delay / Phase Adjustment Unit 802 Subtraction Unit 901 Interference Signal Detection Antenna 902 channel selection unit 903 local signal generation unit 1201 channel selection unit 1202 gain / delay / phase adjustment unit 1203 subtraction unit 1401 gain / delay / phase adjustment unit 1402 subtraction unit 1501 signal processing unit 1502 control unit

Claims (7)

A plurality of branches each having a receiving antenna and a demodulating unit; a combining unit that combines the output signals of the plurality of branches to receive diversity; and a signal processing unit that inputs the output signal of the combining unit and performs decoding and error correction In a receiving device having
A detection antenna that receives radio waves that are interference signals, different from the reception antenna,
Input the interference signal received and converted by the detection antenna, adjust at least one of gain, delay, and phase, and output at least one adjustment interference signal;
A receiving apparatus comprising: at least one subtraction unit that subtracts the adjustment interference signal from a reception signal of at least one branch of the diversity reception, and inputs an output signal of the subtraction unit to the demodulation unit. A plurality of branches each having a receiving antenna and a demodulating unit; a combining unit that combines the output signals of the plurality of branches to receive diversity; and a signal processing unit that inputs the output signal of the combining unit and performs decoding and error correction In a receiving device having
A plurality of detection antennas that receive radio waves that become interference signals, apart from the reception antenna,
Input a plurality of interference signals received and converted by the plurality of detection antennas, adjust at least one of gain, delay, and phase, and output a plurality of adjustment interference signals, respectively;
Providing at least one subtracting unit for subtracting a plurality of the adjustment interference signals from the received signal of at least one branch of the diversity reception in series or in parallel, and inputting the output signal of the final stage of the subtracting unit to the demodulating unit; A receiving device. A plurality of branches by a receiving antenna, a frequency converter that converts a necessary band of a received signal received by the receiving antenna into a demodulated frequency and outputs a frequency converted received signal, and a demodulator that demodulates the frequency converted received signal; In a receiving apparatus including a combining unit that combines the output signals of the plurality of branches and performs diversity reception, and a signal processing unit that inputs the output signal of the combining unit and performs decoding and error correction.
A detection antenna that receives radio waves that are interference signals, different from the reception antenna,
An interference frequency converter that converts the necessary band of the interference signal into the demodulation frequency and outputs a frequency-converted interference signal;
Input the frequency conversion interference signal, adjust at least one of gain, delay and phase, and output at least one adjustment interference signal; and
A receiving apparatus comprising: at least one subtracting unit that subtracts the adjustment interference signal from the frequency converted received signal of at least one of the branches, and inputs an output signal of the subtracting unit to the demodulating unit. A plurality of branches by a receiving antenna, a frequency converting unit that converts a necessary band of a received signal from the receiving antenna into a demodulated frequency and outputs a frequency converted received signal, and a demodulator that demodulates the frequency converted received signal, In a receiving apparatus having a combining unit that combines the output signals of a plurality of branches and performs diversity reception, and a signal processing unit that inputs the output signal of the combining unit and performs decoding and error correction,
A plurality of detection antennas for detecting jamming signals different from the reception antenna;
A plurality of jamming frequency converters for converting the required bands of the plurality of jamming signals into the demodulation frequency and outputting a plurality of frequency conversion jamming signals;
A plurality of adjustment units for inputting the plurality of frequency conversion interference signals, adjusting at least one of gain, delay, and phase, and outputting each of the plurality of adjustment interference signals;
Providing at least one subtracting section for subtracting a plurality of adjustment interference signals from the frequency converted received signal of at least one branch in series or in parallel, and inputting the output signal of the final stage of the subtracting section to the demodulating section; A receiving device. In the receiving device according to claim 3 or 4,
In the frequency conversion unit of the branch provided with the interference frequency conversion unit and the subtraction unit, a local oscillation signal used to convert the input signal of the interference frequency conversion unit or the frequency conversion unit into the demodulation frequency, A receiving apparatus characterized by having the same reference signal for generating a local oscillation signal.   5. The receiving device according to claim 1, wherein the adjusting unit is controlled so that an index indicating a C / N or a degree of distortion of an input signal of the demodulating unit of the branch provided with the subtracting unit is good. A receiving device.   5. The receiving apparatus according to claim 1, wherein the adjustment unit is controlled so that an error rate of the signal processing unit is good.

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