JP3502336B2 - Interference wave cancellation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the fields of broadcasting and communication, and when two signals having different frequency bands and different bandwidths interfere with each other, the received power of an interference wave signal is a desired wave. The present invention relates to an interference wave canceling device that is additionally added to a receiving facility under a receiving condition sufficiently larger than the received power of a signal and cancels an interference wave signal and outputs only a desired wave signal.

[0002]

2. Description of the Related Art As a technique for removing an interference wave, in the field of communication, an interference wave cancel device using an adaptive array antenna, an interference wave cancel device in a CDMA system, and an interference wave cancel device in polarization multiplexing transmission. Various types of interference wave canceling devices have been developed. Further, in the field of broadcasting, technologies such as a ghost canceller, a device for removing interference from television broadcasts by a sporadic E layer, and a detour canceller have been developed.

Conventionally, in an interference wave canceling device, a modulation method and a signal format of a desired wave are known, and a reference signal is included in the desired wave, and this reference signal is used in a predetermined form. Is common. In the case of a ghost canceller, GCR (Ghost Canceller Referenc) which is a known reference signal multiplexed in the vertical blanking period.
e) Utilizing signals. Further, in the above-mentioned practically used removing device, the interference wave is detected in the black signal line in the vertical blanking period. Furthermore, in the detour canceller for realizing broadcast wave relay in SFN for digital terrestrial broadcasting, the SP included in the ISDB-T signal is used.
A method using (Scattered Pilot) as a reference signal has been proposed.

[0004]

If the desired wave has a complicated modulation system or signal format in which digital modulation and analog modulation are mixed or complex modulation is added, cancellation is performed from the result of demodulation of the desired wave. The method of acquiring the residual information has a disadvantage that the scale of the apparatus becomes significantly large. Further, when the power of the interference wave is significantly larger than the power of the desired wave, there is a disadvantage that the cancellation residual information cannot be directly obtained from the desired wave signal. Also,
In some cases, demodulation cannot be performed because of confidentiality protection.

Further, when the condition that the interference wave canceling device is inserted and used before the conventional receiving equipment is added, it may be necessary to minimize the delay amount allowed in the device. In the re-modulation method in which the desired wave is once demodulated and re-modulated, the delay amount becomes large, so this requirement cannot be satisfied. In addition, if the interference wave signal has a non-linear distortion in the transmission line, the canceling performance is deteriorated.

The object of the present invention is to significantly increase the scale of the apparatus even when the desired wave signal has a complicated modulation system or signal format in which digital modulation and analog modulation are mixed or complex modulation is added. You don't have to
Even if the power of the interference wave is significantly higher than the power of the desired wave, the cancellation residual information can be easily obtained, and the interference wave can be removed with high accuracy based on the information.

Another object of the present invention is to provide an interference wave canceling device which does not cause any inconvenience even if a desired wave cannot be demodulated.

Another object of the present invention is to provide an interference wave canceling device which is less affected by the amount of delay in the device even if the condition that the interference wave canceling device is inserted and used in the previous stage of the conventional receiving equipment is added. Is to provide.

Another object of the present invention is to provide an interference wave canceling device which does not deteriorate the canceling performance even when the interference wave signal has a non-linear distortion in the transmission line.

[0010]

An interference wave canceling device according to the present invention is a component of an interference wave signal in which a desired wave signal and its digitally modulated signal band are wider than and overlap with the desired wave signal band. Receiving means for receiving a signal, a distributing means for distributing the signal received by the receiving means into two, and one of the signals distributed by the distributing means, the interference wave signal is digitally demodulated. , A generating means for generating the interference wave signal by digital modulation again, and a delay means for delaying the other of the signals distributed by the distributing means by a signal delay caused by the generating means, and An interference wave canceling device comprising subtraction means for subtracting the output signal of the generation means from the output signal of the delay means and outputting only the desired wave signal. Then, the generation means adds the distortion corresponding to the distortion added to the other of the signals distributed by the distribution means to the digital demodulation, and adds the distortion to the digitally modulated interference wave signal again. And an amplitude and phase adjusting means for adjusting the amplitude and phase of the interference wave signal to which the distortion is added, the signal from the subtracting means is divided into two, and one of the signals is divided into the desired wave. While outputting as a signal, from the other signal, a signal spectrum within a preset frequency band is extracted, and a detection means for detecting the energy of the signal spectrum as cancel residual energy, and the cancel residual energy is The detection means further comprises a control means for controlling the adjustment parameter of the amplitude and phase adjustment means so as to change the adjustment parameter so as to be minimum. The preset frequency band has a first frequency band having the same frequency band as the frequency band of the interference wave signal and a frequency band narrower than the frequency band of the interference wave signal, and the desired wave A second frequency band set close to the frequency band of the signal, wherein the detecting means controls the signal having information about the cancellation residual energy detected in the first and second frequency bands. It is characterized in that it is configured to be supplied to the means.

According to the present invention, since the cancellation residual information of the interference wave signal is obtained without demodulating the desired wave signal, the device scale can be reduced, and the power of the interference wave is the power of the desired wave. It is possible to easily obtain the cancellation residual information even if it is significantly larger than the above, and it is possible to remove the interference wave with high accuracy based on the information.

Further, since the interference wave signal is canceled without demodulating the desired wave signal, there is no inconvenience even if a situation in which demodulation cannot be performed due to protection of confidentiality occurs, and the signal distributed by the distribution means is Since it is only necessary to delay the other one by the signal delay caused by the generation means, even if the condition of inserting the interference wave cancel device in the preceding stage of the conventional receiving equipment and using it is added, the present invention It is possible to apply the interference wave canceling device.

Further, even if the interference wave signal has a non-linear distortion in the transmission line, the cancellation performance is not deteriorated by adding the distortion having the same characteristic to the signal generated by the generating means.

Preferably, the generating means digitally demodulates a distortion corresponding to the distortion added to the other of the signals distributed by the distributing means, and adds the distortion to the digitally modulated interference wave signal again. It has a strain adding means.

More preferably, the generation means further comprises amplitude and phase adjustment means for adjusting the amplitude and phase of the distortion-added interference wave signal.

Preferably, a quadrature demodulation means for quadrature demodulating the signal output from the receiving means and converting it into an equivalent baseband signal consisting of I and Q signals, and the equivalent baseband signal are the distributing means and delay. Means and subtracting means, and quadrature modulating means for converting the equivalent baseband signal into an IF signal.

When the quadrature demodulation means is composed of an analog circuit, it is preferable that the quadrature demodulation means further comprises a correction means for correcting the quadrature error generated by the quadrature demodulation means.

Further, the signal from the subtraction means is divided into two, one of the signals is output as the desired wave signal, and the signal spectrum within a preset frequency band is extracted from the other signal. And detecting the energy of the signal spectrum as cancel residual energy, and adjusting at least one of the amplitude and phase adjusting means and the correcting means so that the cancel residual energy is minimized. And a control means for controlling the parameter to be changed, wherein the preset frequency band has a first frequency band having the same frequency band as the frequency band of the interference wave signal, and the interference wave signal. A second frequency band having a frequency band narrower than the frequency band and set close to the frequency band of the desired wave signal The comprises the detecting means, a signal having information about the first and second cancel residual energy detected by the frequency band may be configured to supply to the control means.

The generating means further includes another distortion adding means and another amplitude and phase adjusting means, divides the digitally demodulated and again digitally modulated interference wave signal into two, and distributes the divided signal. One of the other distortions is supplied to the distortion adding means, and the other of the distributed signals is added to a distortion equivalent to the distortion added to the other of the signals distributed by the distributing means. The output signal of the delay means is divided into two, and one of the divided output signals is supplied to one input terminal of the subtraction means. The output signal of the amplitude and phase adjusting means is supplied to the other input terminal of the subtracting means, and the other of the distributed output signals is
The output signal of the other amplitude and phase adjusting means is supplied to the other subtracting means, and the output signal of the subtracting means is supplied to the other input terminal of the other subtracting means. And outputs the output signal to the detection means by the other subtraction means, and the detection means outputs the desired signal of the cancellation residual energy together with a signal having information about the cancellation residual energy. A narrow band signal in the vicinity of the signal is detected, and a signal having information about these cancellation residual energies and a narrow band signal in the vicinity of the desired wave signal are configured to be supplied to the control means, and the other distortion adding means and the By changing the adjustment parameters of the other amplitude and phase adjusting means, the control direction of the parameter for reducing the cancellation residual energy is detected, and the result is It said control means may operate to reflect the distortion adding means and said amplitude and phase adjusting means.

Preferably, the detecting means sets the preset frequency band so as to be adjacent to at least one of an upper side and a lower side of the frequency band of the desired wave signal.

Preferably, the correction means detects an error vector between the average position of the constellation of the interference wave signal and the normal position, and calculates an orthogonal error based on the detected error information of the constellation. To correct.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an interference wave canceling device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining the principle of an interference wave cancel device according to the present invention. In the graphs of FIGS. 1A to 1D, the vertical axis represents the amplitude and the horizontal axis represents the frequency. In this case, a signal including the desired wave signal A and the interference wave signal B is input to the interference wave cancel device according to the present invention, and as shown in FIG. 1A, the band of the desired wave signal A and the interference wave signal B is input. And the band of the desired wave signal A is significantly narrower than the band of the interference wave signal B, and the received power of the interference wave signal B is significantly larger than the received power of the desired wave signal A. .

The replica signal C of the interference wave signal B having a spectrum as shown in FIG. 1B is generated by digitally demodulating the interference wave signal B once and digitally modulating the interference wave signal B again using the digital data. It

The desired wave signal A can be modulated by any method. Since the interference wave signal B is a signal modulated by a known digital modulation method and is at a level sufficiently higher than the desired wave signal A, a replica signal C having a spectrum as shown in FIG. 1B is generated. be able to.

A transmission line distortion characteristic caused by TWT or the like is added to such a replica signal C to generate a replica interference wave signal D having the same spectrum as the interference wave signal B (FIG. 1 (c)).

When the replica interference wave signal D is subtracted from the desired wave signal A and the interference wave signal B, the interference wave cancel device outputs only the desired wave signal A (FIG. 1 (d)). In the process of generating the replica interference wave signal D, there is only delay such as digital demodulation and modulation and filter processing for adding transmission path distortion characteristics, and it is not necessary to demodulate and modulate the narrow band desired wave signal A. The delay time in the interference cancel device according to the present invention is very small.

If such processing is not performed, that is, if the interference wave cancel device according to the present invention as described in detail later is not used, the desired wave signal A is interfered with by the interference wave signal B, so demodulation is performed. I can't. In the case of the interference wave cancel device according to the present invention, the desired wave signal A
Since the interference wave signal B is canceled without demodulating the signal, it does not depend on the modulation method of the desired wave signal A. as a result,
Even if the desired wave signal has a complicated modulation method or signal format, the scale of the device does not increase.

FIG. 2 is a diagram showing a first embodiment of an interference wave cancel device according to the present invention. This interference wave cancel device includes a reception circuit 1 and a replica generation block 2
And a reception signal delay circuit 3 and a subtractor 4. The replica generation block 2 includes a digital demodulation circuit 2-1, a carrier reproduction circuit 2-2, a digital modulation circuit 2-3,
The transmission line distortion adding circuit 2-4 and the amplitude / phase adjusting circuit 2-5 are included.

FIG. 2 illustrates a case where the interference wave signal B is canceled when a digitally modulated signal such as PSK exists as the interference wave signal B with respect to the desired wave signal A.

The receiving circuit 1 receives a signal composed of a desired wave signal A and an interference wave signal B having a spectrum as shown in FIG. 1 (a), converts the signal into an IF signal and outputs it. This IF signal is distributed to the replica generation block 2 and the reception signal delay circuit 3.

IF distributed to the replica generation block 2
The signal is input to the digital demodulation circuit 2-1 and the carrier reproduction circuit 2-2. The carrier signal reproduced for digital modulation / demodulation is supplied from the carrier reproduction circuit 2-2 to the digital demodulation circuit 2-1 and the digital modulation circuit 2-3. The digital demodulation circuit 2-1 outputs the digitally demodulated signal to the digital modulation circuit 2-3.

As shown in FIG. 1A, since the level of the interference wave signal B is sufficiently higher than the level of the desired wave signal A, the interference wave signal B which is a digital modulated wave can be demodulated without error. It is possible to obtain the original data string.
Therefore, the digital modulation circuit 2-3 completely eliminates the component of the desired wave signal A by performing digital modulation again using the data sequence output from the digital demodulation circuit 2-1, and only the interference wave signal B is lost. A replica signal C having a spectrum (FIG. 1B) is generated.

The signal output from the digital modulation circuit 2-3 is added with the same distortion as the transmission path distortion that the interference wave signal B receives on the actual transmission path in the transmission path distortion adding circuit 2-4. For example, when distortion occurs in a TWT mounted on a broadcasting satellite, an output filter, or the like, the transmission path distortion adding circuit 2-4 adds distortion having the same characteristics as those of the TWT and the output filter, and the replica interference wave signal D (see FIG. )) Is output.

The amplitude / phase adjusting circuit 2-5 adjusts the amplitude and phase of the replica interference wave signal D output from the transmission path distortion adding circuit 2-4, and outputs the adjusted signal to one input terminal of the subtractor 4. Supply to.

On the other hand, the reception signal delay circuit 3 delays the input IF signal in order to compensate for the signal delay generated in the replica generation block 2. The delayed signal is supplied to the other input terminal of the subtractor 4.

The subtractor 4 subtracts the replica interference wave signal D from the signal having the components of the desired wave signal A and the interference wave signal B, and only the desired wave signal A having the spectrum as shown in FIG. To cancel the interference wave signal B.

FIG. 3 is a diagram showing a second embodiment of the interference wave cancel device according to the present invention. This interference wave canceling device includes an input unit 11 and a replica generation block 1
2, a reception signal delay circuit 13, and subtractors 14 and 15
A wideband observation window power detection circuit 16, a narrowband observation window power detection circuit 17, and a control circuit 18.

The replica generation block 12 includes a digital demodulation circuit 12-1, a carrier reproduction circuit 12-2, a decision identification circuit 12-3, a remapping circuit 12-4, a digital modulation circuit 12-5, and a main line. System transmission line distortion adding circuit 1
2-6, a main line system amplitude / phase adjustment circuit 12-7, a search system transmission line distortion adding circuit 12-8, and a search system amplitude / phase adjustment circuit 12-9.

In this case, the main line system and the search system are provided in the replica generation block 12, the cancel residual energy is detected by using the observation window in the output signal from the subtractor 15, and the main circuit transmission line distortion is detected by the control circuit 18. Additional circuit 12-6,
The adjustment parameters of the main system amplitude / phase adjustment circuit 12-7, the search system transmission line distortion adding circuit 12-8, and the search system amplitude / phase adjustment circuit 12-9 are controlled, respectively.

The signal output from the digital modulation circuit 12-5 is distributed to the main line transmission line distortion adding circuit 12-6 and the search system transmission line distortion adding circuit 12-8. The search system changes the adjustment parameters of the transmission line distortion adding circuit 12-8 and the amplitude / phase adjustment circuit 12-9 to evaluate the cancellation residual energy, thereby determining the control direction of the parameter for reducing the cancellation residual energy. The detection result is reflected in the main line transmission line distortion adding circuit 12-6 and the main line amplitude / phase adjusting circuit 12-7. The search system is a signal system provided separately from the main line system in order to prevent the cancel residual energy of the main line system from temporarily increasing.

In the main line transmission line distortion adding circuit 12-6 and the search system transmission line distortion adding circuit 12-8, the digital modulation circuit 1 is used.
To the replica signal C output from 2-5, distortion having the same characteristics as distortion generated by, for example, a TWT mounted on a broadcasting satellite or an output filter is added. The adjustment parameter of the transmission line distortion is controlled by the control circuit 18.

In the main line system amplitude / phase adjusting circuit 12-7 and the search system amplitude / phase adjusting circuit 12-9, the main line output from the main line system transmission line distortion adding circuit 12-6 and the search system transmission line distortion adding circuit 12-8. The amplitude and the phase of the replica interference wave signal D of the system and the search system are respectively adjusted. The amplitude and phase adjustment parameters are controlled by the control circuit 18.

Each of the subtractors 14 and 15 outputs the desired wave signal A by the same operation as the subtractor 4 of FIG. The wideband observation window power detection circuit 16 detects the cancellation residual energy output from the subtractor 15 and outputs it to the control circuit 1.
Supply to 8. On the other hand, the narrowband observation window power detection circuit 17 detects a narrowband signal near the desired wave signal A in the cancellation residual energy output from the subtractor 15, and supplies it to the control circuit 18.

In general, since the desired wave signal A and the interference wave signal B are uncorrelated, even if the band including the desired wave A is assigned to the narrow band observation window, the power of the desired wave signal A is the same as that of the interference wave signal B. It is only added to the cancellation residual energy, and the adjustment parameter that minimizes the cancellation residual energy can be searched for. On the other hand, when the desired wave signal A and the interference wave signal B are not completely uncorrelated or when the level fluctuation of the desired wave signal A is large, the narrow band observation window is set above and below the frequency band of the desired wave signal A. It is possible to set so as to be adjacent to at least one of them and use the cancellation residual energy to search for the optimum adjustment parameter.

On the other hand, if a broadband observation window is used,
Since the delay time of the observation window filter for extracting the signal spectrum in the observation window is small and the amount of information per unit time is large, the optimum value can be searched in a short time. On the other hand, when the narrow band observation window is used, the delay due to the observation window filter is large and the amount of information per unit time is small, so the time required for the optimum value search is increased as compared with the case where the wide band observation window is used. Since the cancel residual energy of the interference wave signal B can be minimized in the vicinity of the frequency band of the originally desired wave signal A, the canceling effect is further enhanced.

Further, when a method combining these observation windows is used, first, coarse adjustment is performed in a short time using the wide band observation window, and then fine adjustment is accurately performed using the narrow band observation window. The adjustment parameter can be converged accurately in a short time. The concept of the observation window is shown in FIG.

The control circuit 18 exchanges a signal with each circuit having an adjustment parameter, and changes it by a preset step amount so that the cancellation residual energy detected in the observation window is minimized. Then, the setting of each adjustment parameter is updated.

The parameters of the main line transmission line distortion adding circuit 12-6 and the search system transmission line distortion adding circuit 12-8 are adjusted, for example, by adjusting the frequency characteristics of the output filter and the back-off amount of the TWT and adjusting the TWT characteristics. This is done by recording it in ROM and reproducing it.

Next, the third to fifth embodiments for operating using digital signal processing in the equivalent baseband will be described. FIG. 5 is a diagram showing a third embodiment of the interference wave cancel device according to the present invention. This interference wave canceling device includes an input section 21, a receiving circuit 22, an A / D
Converter 23, quadrature demodulation circuit 24, replica generation block 25, carrier regeneration circuit 26, received signal delay circuit 27, subtractors 28 to 31, wideband observation window power detection circuit 32, and narrowband observation window. It includes a power detection circuit 33, a control circuit 34, a quadrature modulation circuit 35, and a D / A converter 36.

When performing digital signal processing, a clock recovery circuit synchronized with the symbol clock of the interference wave is required, but this is an existing technique, and therefore the description and detailed description thereof in this figure are omitted.

The replica generation block 25 includes a determination / identification circuit 25-1, a remapping circuit 25-2, a main line transmission line distortion adding circuit 25-3, and a main line amplitude / phase adjusting circuit 25.
-4, a search system transmission line distortion adding circuit 25-5, and a search system amplitude / phase adjusting circuit 25-6.

In this case, the input section 21 receives a signal in which the desired wave signal A and the digitally modulated interference wave signal B are mixed, and the signal is converted by the receiving circuit 22 into an IF band signal.

The analog signal in the IF band is supplied to the A / D converter 2
It is converted into a digital IF signal by 3 and supplied to the orthogonal demodulation circuit 24. The output signal from the quadrature demodulation circuit 24 is distributed and supplied to the replica generation block 25, the carrier reproduction circuit 26, and the reception signal delay circuit 27. The output signal from the carrier reproduction circuit 26 is distributed and supplied to the quadrature demodulation circuit 24 and the quadrature modulation circuit 35.

The output signal of the quadrature demodulation circuit 24 is an equivalent baseband signal, and the equivalent baseband signal digitized up to the input of the quadrature modulation circuit 35 is processed.
The output signal of the quadrature modulation circuit 35 is input to the D / A converter 36, and the D / A converter 36 outputs the desired wave signal A in the IF band as an analog signal.

In the present embodiment, the analog signal in the IF band is A / D converted immediately after input and D / D converted immediately before output.
After being A-converted, it is output as an analog signal in the IF band.

FIG. 6 is a diagram showing a fourth embodiment of an interference wave cancel device according to the present invention. This interference wave cancel device includes an input unit 41, a quadrature demodulation circuit 42, an A
/ D converters 43 and 44, and replica generation block 45
Carrier recovery circuit 46 and received signal delay circuit 47
A main line system orthogonal error correction circuit 48, a search system orthogonal error correction circuit 49, subtractors 50 to 53, a wide band observation window power detection circuit 54, a narrow band observation window power detection circuit 55, and a control circuit 56. , D / A converters 57 and 58, and a quadrature modulation circuit 59. The replica generation block 45 has the same configuration as the replica generation block 25 of FIG.

In this embodiment, the quadrature demodulation circuit 42 is
It is composed of an analog circuit and is converted into a signal in the equivalent baseband band, and then converted into a digital equivalent baseband signal by the A / D converters 43 and 44, and the output signal of the reception signal delay circuit 47 is further converted into a main line system. Quadrature error correction circuit 48
And the search system orthogonal error correction circuit 49, and by controlling the adjustment parameter by the control circuit 56,
It is possible to prevent deterioration of the cancellation characteristic caused by the orthogonal error.

FIG. 7 is a diagram showing a fifth embodiment of the interference wave cancel device according to the present invention. This interference wave cancel device includes an input unit 71, a quadrature demodulation circuit 72, an A
/ D converters 73 and 74, and replica generation block 75
Carrier recovery circuit 76, quadrature error detection circuit 77
Quadrature error correction circuit 78 and received signal delay circuit 79
, Subtractors 80-83, and broadband observation window power detection circuit 8
4, a narrow band observation window power detection circuit 85, and a control circuit 86
, D / A converters 87 and 88, and a quadrature modulation circuit 89. The replica generation block 75 is similar to the replica generation block 2 in FIG. 5 except that the remapping circuit 75-1 has two outputs to the orthogonal error detection circuit 77.
5 has the same configuration.

In this embodiment, the quadrature error detection circuit 77 is used.
Detects an error vector between the average position of the constellation of the interference wave signal B which is a digital modulated wave and the normal position output from the remapping circuit 75-1, and the quadrature error correction circuit 78 detects the average error from the average error. By calculating and correcting the IQ axis orthogonal deviation θ and the IQ gain balance deviation α, the IQ axis orthogonal deviation θ and the IQ gain balance deviation α are corrected without being controlled by the adjustment parameter.

FIG. 8 is a diagram showing the principle of orthogonal error correction using signals before and after decision mapping on the IQ axis plane. In this case, the error vector between the average position and the normal position is obtained by performing the determination mapping as shown in FIG. 8B for the IQ axis orthogonal deviation θ as shown in FIG. 8A. .

In performing such correction, the IQ axis orthogonal deviation θ that minimizes the error power Perr represented by the following equation
And the optimum value can be calculated by obtaining the deviation α of the IQ gain balance.

[0062]

[Equation 1] in this case,

[0063]

[Outer 1] Is the i-th average position, and I _i and Q _i are the i-th normal positions.

The present invention is not limited to the above embodiment, but various modifications and variations are possible. For example, in the above embodiments, a distributor may be used when distributing the received signal.

In the above embodiment, the case where the interference wave signal B is PSK modulation has been described, but the same canceling effect can be obtained by other digital modulation methods. Further, the case where the level of the interference wave signal B is sufficiently higher than the level of the desired wave signal A has been described, but even when the level of the desired wave signal A is approximately the same as the level of the interference wave signal B, the interference wave signal Depending on the frequency relationship with B, the interference wave cancel device according to the present invention operates effectively.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of an interference wave cancel device according to the present invention.

FIG. 2 is a diagram showing a first embodiment of an interference wave cancel device according to the present invention.

FIG. 3 is a diagram showing a second embodiment of an interference wave cancel device according to the present invention.

FIG. 4 is a conceptual diagram of an observation window.

FIG. 5 is a diagram showing a third embodiment of an interference wave cancel device according to the present invention.

FIG. 6 is a diagram showing a fourth embodiment of an interference wave cancel device according to the present invention.

FIG. 7 is a diagram showing a fifth embodiment of an interference wave cancel device according to the present invention.

FIG. 8 is a principle diagram of orthogonal error correction using signals before and after decision mapping.

[Explanation of symbols]

1, 22 Reception circuit 2, 12, 25, 45, 75 Replica generation block 2-1, 12-1 Digital demodulation circuit 2-2, 12-2, 26, 46, 76 Carrier reproduction circuit 2-3, 12-5 Digital modulation circuit 2-4 Transmission line distortion adding circuit 2-5 Amplitude / phase adjustment circuit 3, 13, 27, 47, 79 Received signal delay circuit 4, 14, 15, 28, 29, 30, 31, 50, 5
1, 52, 53, 80, 81, 82, 83 Subtractors 11, 21, 41, 71 Input section 16, 32, 54, 84 Wide band observation window power detection circuit 17, 33, 55, 85 Narrow band observation window power detection Circuit 18, 34, 56, 86 Control circuit 12-3, 25-1 Judgment identification circuit 12-4, 25-2, 75-1 Remapping circuit 12-6, 25-3 Main line system transmission line distortion adding circuit 12- 7, 25-4 Main line amplitude / phase adjusting circuit 12-8, 25-5 Search system transmission line distortion adding circuit 12-9, 25-6 Search system amplitude / phase adjusting circuit 23, 43, 44, 73, 74 A / D Converters 24, 42, 72 Quadrature demodulation circuit 48 Main line system orthogonal error correction circuit 49 Search system orthogonal error correction circuit 35, 59, 89 Quadrature modulation circuit 36, 57, 58, 87, 88 D / A converter 77 Quadrature error detection Circuit 78 Quadrature error correction circuit Path A Desired wave signal B Interference wave signal C Replica signal D Replica interference wave signal

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Mizuki 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Broadcasting Research Institute of Japan Broadcasting Corporation (72) Inventor Hashimoto 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Technology Research Institute (72) Inventor Jun Matsumoto 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Technology Research Institute (72) Inventor Junji Kumada 1-1-10 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Yukio Noda 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Center (72) Inventor Hiroshi Hirabayashi 2-2-1, Shinan-ku, Tokyo Japan Broadcasting Association Broadcasting Center (72) Inventor Takao Kuki 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Japan Broadcasting Corporation Broadcasting Technology Laboratory (56) References JP-A-9-261086 (JP, A) JP-A 11-17762 (JP, A) JP-A 11-136302 (JP, A) JP-A 2000-216703 (JP, A) JP 2000-339320 (JP, A) JP 9-130439 (JP, A) JP 10-56394 (JP, A) JP 2000-36778 (JP, A) JP 10-178373 (JP, A) ) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 1/00 H04B 3/00 H04B 7/00 H04L 27/00

Claims (5)

(57) [Claims] 1. Receiving means for receiving a desired wave signal and a signal having a component of an interference wave signal whose digitally modulated signal band is wider than and overlaps with the desired wave signal band, and the receiving means. The interference wave signal is digitally demodulated and digitally modulated again with respect to one of the signals distributed by the distributing means and the signal distributed by the distributing means. Generating means for generating, and the other of the signals distributed by the distributing means,
An interference wave comprising delay means for delaying the signal delay caused by the generating means, and subtracting means for subtracting the output signal of the generating means from the output signal of the delay means and outputting only the desired wave signal. In the canceling device, the generating unit digitally demodulates a distortion corresponding to the distortion added to the other of the signals distributed by the distributing unit, and adds the distortion to the digitally modulated interference wave signal again. Distortion adding means, having an amplitude and phase adjusting means for adjusting the amplitude and phase of the interference wave signal to which the distortion is added, the signal from the subtracting means is divided into two, one of the signals is In addition to outputting as the desired wave signal, a signal spectrum within a preset frequency band is extracted from the other signal and the energy of the signal spectrum is canceled. Detecting means for detecting as a difference energy, further comprising a control means for controlling so as to change the adjustment parameter of the amplitude and phase adjusting means, so that the cancellation residual energy is minimized, the detection means in advance. The set frequency band has a first frequency band having the same frequency band as the frequency band of the interference wave signal, and a frequency band narrower than the frequency band of the interference wave signal, and the frequency of the desired wave signal. A second frequency band set close to the band, the detection means supplying a signal having information about the cancellation residual energy detected in the first and second frequency bands to the control means. An interference wave canceling device characterized in that 2. A quadrature demodulation means for quadrature demodulating the signal output from the receiving means and converting it into an equivalent baseband signal composed of I and Q signals, and the equivalent baseband signal being the distributing means, the delay means and the The interference wave canceling apparatus according to claim 1, further comprising: a quadrature modulation unit that is input through a subtraction unit and that converts the equivalent baseband signal into an IF signal. 3. The interference wave canceling apparatus according to claim 2, wherein the quadrature demodulating means is composed of an analog circuit, and further comprises a correcting means for correcting a quadrature error generated by the quadrature demodulating means. 4. The correcting means detects an error vector between an average position of a constellation of the interference wave signal and a normal position, and calculates and corrects an orthogonal error from error information of the detected constellation. The interference wave cancel device according to claim 3, wherein the interference wave cancel device is configured as described above. 5. The detection means is configured to set the preset frequency band so as to be adjacent to at least one of an upper side and a lower side of the frequency band of the desired wave signal. Item 5. The interference wave cancel device according to any one of items 1 to 4.