JP2002141821A - Wireless device - Google Patents

Abstract

[PROBLEMS] To be able to correct the group delay distortion of an analog bandpass filter by digital signal processing, to have high stability of frequency characteristics, to eliminate the need for adjustment, and not to increase the circuit scale. Such a group delay characteristic correction circuit is realized. An RF signal received by an antenna (5) is frequency-converted by a mixer (6), band-limited by a band-pass filter (7), and receives group delay distortion. Further, the frequency is again converted by the mixer 8, the band is limited by the band-pass filter 9, and a group delay distortion is caused. Next, the quadrature demodulation unit 10 performs quadrature demodulation, the A / D conversion unit 11 subjects the in-phase component and the quadrature component to A / D conversion, and stores the analog bandpass filters 7 and 9 stored in the storage unit 16. A digital filter having a delay characteristic and an inverse characteristic is subjected to filter operation processing by operation means 12, and signal demodulation is performed by signal demodulation section 13. Thereby, it is possible to reduce a code determination error at the time of signal demodulation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio apparatus in digital radio communication, and more particularly, to a radio apparatus having a group delay characteristic correction device for correcting a group delay characteristic of an analog filter.

[0002]

2. Description of the Related Art Conventionally, RF (Radio Frequency)
An analog bandpass filter is used for limiting a wireless channel band in a band and an IF (Intermediate Frequency) band. However, since the conventional wireless system requires a wide wireless channel bandwidth and moderate cutoff characteristics, the group delay characteristic of the analog bandpass filter does not cause a significant increase in the error rate of data decoding. Therefore, a simple LC resonance circuit or the like is used for the analog bandpass filter.

[0003]

However, in recent years, the band of wireless channels has been narrowed from the viewpoint of effective use of frequency.
Along with that, due to the steep cut-off characteristic of the analog bandpass filter for separating adjacent channels,
The group delay distortion in which the middle part is concave and the convex part is convex on both sides is an adverse effect on communication. That is, due to the group delay distortion, the linearity of the in-band frequency characteristic is not maintained, which causes an increase in the code decision error rate when performing data decoding.

A method for correcting the group delay characteristic of such an analog filter has been proposed, for example, in Japanese Patent No. 2728244. According to the technique of this publication, a single-peak characteristic that is convex between resonance frequencies or between anti-resonance frequencies is created by a group delay equalizer including an LC resonance circuit,
By combining with a conventional ceramic filter having a bimodal characteristic, a flat group delay characteristic is obtained, distortion is reduced, and the linearity of the in-band frequency characteristic is improved.

[0005] However, as disclosed in the above-mentioned publication, L
In the group delay equalizer including the C resonance circuit, there is a problem that adjustment for obtaining a predetermined frequency characteristic is required, and although the frequency characteristic is improved, the stability of the frequency characteristic is lacking. Further, since the group delay equalizer is realized by a circuit element, the circuit scale is increased, and there is a possibility that cost and reliability may be reduced.

Japanese Unexamined Patent Publication No. Hei 8-139601 proposes a digital signal processing circuit for correcting group delay characteristics of an analog low-pass filter. According to the technique disclosed in this publication, the group delay characteristic is flattened by using a digital all-pass filter having a group delay characteristic opposite to the group delay characteristic of the analog low-pass filter.

However, in the field of audio processing and the like, it is important to correct the group delay characteristic of the analog low-pass filter as described above.
It is necessary to correct the characteristics of the band-pass filter in the F band, that is, the group delay characteristics in which the middle portion is concave and both sides are convex. Therefore, the technique disclosed in the above publication cannot correct the group delay characteristic of the bandpass filter required by the wireless device.

[0008] The present invention has been made in view of such circumstances, and an object thereof is to correct the group delay distortion of an analog bandpass filter by digital signal processing.
Provided is a radio apparatus having a group delay characteristic correction device which has high frequency characteristic stability, does not require adjustment, and can be easily realized even in a conventional system without increasing the circuit scale. Is to do.

[0009]

In order to solve the above-mentioned problems, a radio device according to the present invention is a radio device of a single superheterodyne type or a radio device having a single analog bandpass filter for limiting a reception band. And an arithmetic means for performing a filter operation using a digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter and a reception signal received by its own reception unit. .

That is, according to the radio apparatus of the present invention, the arithmetic means uses the group delay characteristic of the analog band-pass filter having the concave middle portion and the convex sides on the both sides to perform analog processing on the distorted received signal. Filter operation is performed using a digital filter having a characteristic opposite to the group delay characteristic of the bandpass filter. That is, by providing a group delay characteristic correction device that performs such a filter operation and correcting the group delay distortion, it is possible to correct the group delay characteristic with stable frequency characteristics.

The radio apparatus of the present invention is a double superheterodyne radio apparatus or a radio apparatus having a plurality of analog bandpass filters for limiting a reception band, wherein each group delay of the plurality of analog bandpass filters is different. A digital filter having characteristics opposite to the characteristics or the group delay total characteristics obtained by aggregating the respective group delay characteristics, and an operation means for performing a filter operation using a received signal received by its own receiver. It is characterized by.

That is, according to the radio apparatus of the present invention, even when a radio apparatus having a double superheterodyne radio apparatus or a radio apparatus having a plurality of analog bandpass filters for limiting a reception band is used, the above-mentioned single super heterodyne radio apparatus is used. The group delay characteristic can be corrected by exactly the same means as in the case of a heterodyne wireless device or a wireless device having a single analog bandpass filter for limiting a reception band.

Further, the radio apparatus according to the present invention, in the above invention, further comprises storage means for holding a coefficient of the digital filter, wherein the calculation means performs a filter calculation based on the digital filter extracted from the storage means. Features.

That is, according to the wireless device of the present invention, when the arithmetic means performs the filter arithmetic processing, the digital filter obtained in advance is stored in the storage means, and the arithmetic operation is performed by the digital filter taken out from the storage means. By
The correction of the group delay characteristic is performed. According to such a correction method, it is possible to perform quick correction of the group delay characteristic using a hard logic or the like with a small operation delay.

Further, in the wireless device of the present invention, in the above invention, the storage means holds the coefficients of a plurality of digital filters having different characteristics, and the selection means for selecting the optimum digital filter coefficient from the storage means. And a calculation means for performing a filter calculation based on the coefficient of the digital filter selected by the selection means.

That is, according to the radio apparatus of the present invention, since the correction of the group delay characteristic is performed by selecting the optimum coefficient of the digital filter, the correction is always performed by following the fluctuation of the group delay characteristic depending on the parameter. It can be carried out.

Further, the radio apparatus according to the present invention, in the above invention, comprises an estimating means for estimating a coefficient of a digital filter having an inverse characteristic of the group delay characteristic from an input / output signal or an output signal of an arbitrary analog bandpass filter. The arithmetic means corrects the group delay characteristic using the digital filter estimated by the estimating means.

That is, according to the radio apparatus of the present invention, it is possible to perform correction following the time variation of the group delay characteristic.

Further, in the wireless device of the present invention, in the above invention, the selection means selectively switches between a coefficient of the digital filter previously stored in the storage means and a coefficient of the digital filter estimated by the estimation means. It is characterized by having means.

That is, according to the radio apparatus of the present invention, the switching means for selectively switching between the group delay inverse characteristic filter estimated by the estimating means and the filter stored in the storage means in advance is provided. , The correction of the group delay characteristic of an analog filter having a high level can be realized.

Further, in the wireless device of the present invention, in the above invention, the calculating means may include a digital filter having a characteristic opposite to a group delay characteristic of the analog bandpass filter and a reception signal received by the receiving unit of the wireless device. Is used to perform a filter operation by a complex operation.

That is, according to the radio apparatus of the present invention, since the filter operation is executed by the complex operation to correct the group delay characteristic, the amount of operation can be reduced.

Further, in the wireless device of the present invention, in the above invention, the calculating means receives the real part coefficient of the digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter and the receiving part of the wireless device. A filter operation is performed by real number operation using the received signal thus obtained.

That is, according to the radio apparatus of the present invention, since the filter operation is executed by the real number operation to correct the group delay characteristic, the amount of operation can be reduced.

Further, in the wireless device of the present invention, in the above invention, the arithmetic means convolves the digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter with the existing digital filter, and the convolved digital filter. And a filter operation using the reception signal received by the reception unit of the wireless device.

That is, according to the radio apparatus of the present invention, since the filter operation is performed using the convolved digital filter and the reception signal received by the reception unit of the radio apparatus, the amount of operation can be reduced.

[0027] Further, in the radio apparatus according to the present invention, in the above invention, the existing digital filter is a Nyquist filter, and the correction processing of the group delay characteristic and the correction processing of the Nyquist filter are performed simultaneously.

That is, according to the radio apparatus of the present invention, the correction processing of the group delay characteristic and the correction processing of the Nyquist filter can be performed at the same time, so that the correction processing time can be reduced.

[0029] In the wireless device of the present invention, in the above invention, the calculating means may include a digital filter having a characteristic opposite to a group delay characteristic of the analog bandpass filter and a reception signal received by the receiving unit of the wireless device. And an arithmetic processing selecting means for selectively switching between a processing of performing a filter operation by performing a complex operation and a processing of performing a filter operation by performing a real number operation.

That is, according to the radio apparatus of the present invention, by appropriately switching between the filter operation based on the complex operation and the filter operation based on the real number operation by the operation processing selecting means, the operation amount and the group delay characteristic correction performed by the operation means can be corrected. Can be controlled.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of a device for correcting group delay characteristics in a wireless device according to the present invention with reference to the drawings.
First, the operation principle of the group delay characteristic correction will be described. Figure 1
FIG. 3 is a principle diagram of a group delay characteristic correction device for obtaining an inverse characteristic of a group delay characteristic of an analog filter for performing a group delay characteristic correction. In the figure, a group delay characteristic correction device includes an input unit 1 for inputting a signal, an analog filter 2 having a group delay characteristic, a digital filter 3 having a characteristic opposite to the group delay characteristic, and a correction of the group delay characteristic. And an output section 4 for transmitting an output signal.

In such a configuration of the device for correcting group delay characteristics, when an input signal from the input unit 1 passes through the analog filter 2, it receives a group delay distortion corresponding to the group delay characteristics. Further, by passing through a digital filter 3 having an inverse characteristic of the group delay characteristic of the analog filter 2,
The group delay characteristic correction is performed, and a signal whose frequency has been corrected can be output from the output unit 4.

The LMS (Least Mean Square) or RMS (Least Mean Square) is used so that the impulse response of the entire system from the input unit 1 to the output unit 4 becomes a unit impulse.
If the coefficients of the digital filter 3 are adjusted by using a recursive operation algorithm such as LS (Recursive Least Squares), the digital filter 3 having the inverse characteristic of the group delay characteristic of the analog filter 2 can be obtained.

The provision of the arithmetic means for performing the filter operation with the digital filter coefficient obtained in advance as described above makes it possible to realize the group delay characteristic correction of the analog filter. Further, when the operation of creating the digital filter 3 having the inverse characteristic of the group delay characteristic is performed by changing various parameters, a plurality of digital filters 3 having different inverse group delay characteristics are obtained. 3 for storing a digital filter coefficient in accordance with a parameter value during the operation of the analog filter 2, and a calculating means for performing a filter calculation process with the digital filter selected by the selecting means. By doing so, it is possible to accurately and stably perform the correction that follows the change in the group delay characteristic due to the parameter of the analog filter 2.

Further, by providing estimating means for estimating the digital filter 3 having the inverse characteristic of the group delay characteristic of the analog filter 2 from the input / output result of the analog filter 2, the group following the group delay characteristic fluctuation of the analog filter 2 is provided. It is also possible to perform delay characteristic correction.

Further, by providing a selecting means for selecting a digital filter selected from a plurality of digital filters held in the storage means and a digital filter estimated by the estimating means, a group delay of the analog filter having high reliability is provided. Characteristic correction can also be realized.

Next, the group delay characteristic correction will be described using a double superheterodyne type radio device. The correction operation is exactly the same when a radio device having a plurality of analog bandpass filters for limiting the reception band is used. It is. Further, the correction operation is exactly the same when a single superheterodyne wireless device or a wireless device having a single analog bandpass filter for limiting the reception band is used.

FIG. 2 is a block diagram of an embodiment of the receiving section of the double superheterodyne radio apparatus. In FIG. 2, the double superheterodyne wireless device estimates an antenna 5, mixers 6, 8, analog bandpass filters 7, 9, a quadrature demodulator 10, an A / D converter 11, and a digital filter coefficient. Estimating means 17
And a digital signal processing unit 18.

The digital signal processing section 18 includes an operation section 12 for performing a filter operation, a signal demodulation section 13, a selection section 15 for selecting a digital filter coefficient, and a storage section 16 for storing a digital filter coefficient. Then, the signal output 14 is taken out.
Note that the digital signal processing unit 18 includes a CPU (Central Proc).
An arithmetic unit such as an essing unit or a DSI (Dynamic Support Program) may be used, and a GA (Grapple Adapte) may be used.
Hard logic such as r) may be used.

In FIG. 2, the R received by antenna 5
The F signal is input to the mixer 6, frequency-converted to a first intermediate frequency, and input to the analog bandpass filter 7. Further, the signal input to the analog bandpass filter 7 is band-limited, receives a group delay distortion having a concave middle portion and a convex shape on both sides, and is input to the mixer 8.

The signal input to the mixer 8 is frequency-converted to a second intermediate frequency, and is converted to an analog band-pass filter 9.
Is input to Further, the analog bandpass filter 9
Is subjected to band limitation again, receives a group delay distortion having a concave middle portion and a convex shape on both sides, and receives a quadrature demodulator 10.
Is input to

The signal input to the quadrature demodulation unit 10 is subjected to quadrature demodulation simultaneously with frequency conversion, separated into an in-phase component I and a quadrature component Q, and input to the A / D conversion unit 11, respectively. Further, each signal input to the A / D converter 11 is A / D converted and input to the digital signal processor 18.

Further, the received signal input to the digital signal processing section 18 passes through the arithmetic means 12 and the signal demodulation section 13 and is taken out as a signal output 14.

Here, the calculating means 12 performs a filter calculating process for correcting the group delay characteristic with a digital filter having an inverse characteristic of the group delay characteristic, and the signal demodulating section 13 performs signal demodulation.

In the filter operation performed by the operation means 12, the digital filter obtained in advance is stored in the storage means 16 and the operation is performed by the digital filter taken out of the storage means 16, thereby obtaining the group delay characteristic correction. Can be performed. According to such a correction method, it is also possible to quickly correct the group delay characteristic using a hard logic or the like with a small operation delay.

Further, by providing the selecting means 15 for selecting the optimum digital filter coefficient from the storage means 16 storing the single or plural digital filter coefficients obtained in advance, the variation of the group delay characteristic depending on the parameter is provided. It is possible to perform the correction by following.

Further, the digital filter generated by the estimating means 17 for estimating the inverse characteristic of the group delay characteristic from the output signal after passing through the analog bandpass filter 9 or the input / output signal sandwiching the analog bandpass filters 7, 9 It is also possible to perform the processing of the group delay characteristic correction by the calculating means 12 by using. As a result, it is possible to perform the correction that follows the time variation of the group delay characteristic.

The estimating means 12 inputs a pulse to the input stage of the analog bandpass filter 7, for example,
A method for estimating the inverse characteristic of the group delay characteristic from the output signal of the analog bandpass filter 9 at that time, and the inverse characteristic of the group delay characteristic from the output signal data of the received input signal after passing through the analog bandpass filters 7 and 9. The estimation is performed by a method for estimating.

FIG. 3 is a block diagram of another embodiment of the receiving section of the double superheterodyne radio apparatus.
That is, this embodiment is different from the embodiment shown in FIG. 2 only in that the estimating unit 17 is brought into the digital signal processing unit 18. Therefore, FIG.
As shown in (1), there is also a method in which the estimating means 12 estimates the inverse characteristic of the group delay characteristic from the received data at the output stage of the A / D converter 11.

Further, it is possible to provide the selecting means 15 with a switching means for selectively switching between the group delay inverse characteristic filter estimated by the estimating means 17 and the filter stored in the storage means in advance. As a result, highly reliable group delay characteristic correction of the analog filter can be realized.

FIG. 4 shows the operation means 12 shown in FIGS.
FIG. 2 is a block diagram showing the configuration of the first embodiment.
In FIG. 4, I data 19 of an in-phase component subjected to A / D conversion after quadrature demodulation of an input signal and Q data 20 of quadrature components subjected to A / D conversion after quadrature demodulation of an input signal are respectively provided by a digital filter. Real part filter coefficient (Fi) 2
1 and the imaginary part filter coefficient (Fq) of the digital filter
22 and is input to the signal demodulation unit 23. That is, the I data 19 of the in-phase component and the Q data 20 of the quadrature component are subjected to a complex filter operation by a digital filter, and are input to the signal demodulation unit 23. That is, according to the first embodiment shown in FIG. 4, the arithmetic unit includes a digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter and a reception signal received by the reception unit of the wireless device. , A filter operation is performed by a complex operation, and then input to the signal demodulation unit.

FIG. 5 shows the operation means 12 shown in FIGS.
FIG. 9 is a block diagram showing the configuration of the second embodiment.
In FIG. 5, the in-phase component I data 19 and the quadrature component Q data
The data 20 is subjected to arithmetic processing on a real part filter coefficient (Fi) 21 of a digital filter and input to a signal demodulation unit 23. Therefore, according to the second embodiment shown in FIG. 5, the calculating means determines whether the real part coefficient of the digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter is received by the receiving part of the wireless device. Filter operation is performed using the received signal thus obtained.

As described above, the I data 19 and the Q data 20
Are processed by a digital filter using a real part filter, and input to a signal demodulation unit, whereby the amount of calculation can be reduced.

FIG. 6 shows the operation means 12 shown in FIGS.
FIG. 13 is a block diagram showing the configuration of the third embodiment.
In FIG. 6, I data 19 of the in-phase component and Q data of the quadrature component
The data 20 is input to a digital filter of Fi * root Nyquist 24 which is a convolution of an existing digital filter (for example, a root Nyquist filter) with a real part digital filter coefficient (Fi). Is input to

That is, I data 19 and Q data 20 are
The group delay characteristic correction processing and the Nyquist filter processing are simultaneously performed by the Fi * root Nyquist 24, and the signal demodulation unit 23
Is input to Therefore, according to the third embodiment shown in FIG. 6, the calculating means convolves the digital filter having the characteristic opposite to the group delay characteristic of the analog bandpass filter with the existing digital filter, and the convolved digital filter The filter operation is performed on the received signal and the reception signal received by the reception unit of the wireless device, and then input to the signal demodulation unit 23.

FIG. 7 shows the operation means 12 shown in FIGS.
FIG. 14 is a block diagram showing the configuration of the fourth embodiment.
That is, the fourth embodiment shown in FIG. 7 is different from the configuration of the first embodiment shown in FIG. 4 in that an arithmetic processing selecting means 25 for selecting a digital filter arithmetic processing is added. That is, in the fourth embodiment shown in FIG.
The filter processing by the complex operation of the first embodiment shown in FIG. 4 and the filter operation by the real number operation of the second embodiment shown in FIG. 5 are selectively switched by the operation processing selecting means 25. Things. As described above, by switching the method of the arithmetic processing by the arithmetic processing selecting means 25, it becomes possible to control the amount of arithmetic performed by the arithmetic means and the accuracy of the group delay characteristic correction.

FIG. 8 is a characteristic diagram measured in a radio apparatus which is input to a digital filter of the Fi * root Nyquist 24 shown in FIG. 6 and is subjected to arithmetic processing. In other words, this characteristic diagram is a characteristic curve showing the relationship between the reception input voltage on the horizontal axis and the BER (Bit Error Rate) on the vertical axis.

FIG. 8A shows data before the correction of the group delay characteristic, and FIG. 8B shows the data after the correction of the group delay characteristic. As is apparent from the figure, the correction of the group delay characteristic according to the present invention has almost no BER recession (that is, an increase in code determination error is suppressed) when the reception input voltage is around 20 to 50 dBμV, and the group delay characteristic correction is performed. It can be seen that the effect of is exhibited. In this way, a flat group delay characteristic is obtained, distortion is reduced, and the linearity of the in-band frequency characteristic is improved.

[0059]

As described above, according to the radio apparatus of the present invention, when correcting the group delay characteristic, it is not necessary to perform adjustment for obtaining a predetermined characteristic, and the stability of the frequency characteristic is also improved. high. Furthermore, since the correction of the group delay characteristic can be realized by software, the circuit scale of the system does not increase. Further, by convoluting the inverse characteristic filter of the group delay characteristic with the existing digital filter, the calculation time for the correction processing of the group delay characteristic can be reduced, so that the delay time due to the correction processing does not increase. Further, by creating a digital filter, adaptation to a conventional wireless device can be easily performed.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a group delay characteristic correction device for obtaining an inverse characteristic of a group delay characteristic of an analog filter for performing a group delay characteristic correction.

FIG. 2 is a block diagram of an embodiment of a receiving unit of the double superheterodyne wireless device;

FIG. 3 is a block diagram of another embodiment of the receiving unit of the double superheterodyne wireless device;

FIG. 4 is a block diagram showing a configuration of a first embodiment of the arithmetic means 12 shown in FIGS. 2 and 3;

FIG. 5 is a block diagram showing the configuration of a second embodiment of the calculating means 12 shown in FIGS. 2 and 3;

FIG. 6 is a block diagram showing the configuration of a third embodiment of the calculating means 12 shown in FIGS. 2 and 3;

FIG. 7 is a block diagram showing the configuration of a fourth embodiment of the calculating means 12 shown in FIGS. 2 and 3;

FIG. 8 is a characteristic diagram measured in a wireless device which is input to a digital filter of Fi * root Nyquist 24 shown in FIG. 6 and is subjected to arithmetic processing;

[Explanation of symbols]

 Reference Signs List 1 input unit 2 analog filter 3 digital filter 4 output unit 5 antenna 6, 8 mixer 7, 9 analog bandpass filter 10 quadrature demodulation unit 11 A / D conversion unit 12 operation unit 13 signal demodulation unit 14 signal output 15 selection unit 16 storage Means 17 Estimation Means 18 Digital Signal Processing Unit 19 I Data 20 Q Data 21 Real Part Filter Coefficient (Fi) 22 Imaginary Part Filter Coefficient (Fq) 23 Signal Demodulation Unit 24 Fi * Root Nyquist 25 Operation Processing Selection Means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Amataka Tomameji 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (72) Kunihiko Sakaihara Tsunashima, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd. F-term (reference) 5K004 AA01 BA02 BD01 5K020 DD09 DD26 FF04 HH13 KK04 NN10 5K022 AA23

Claims (11)

[Claims] 1. A single superheterodyne wireless device or a wireless device having a single analog bandpass filter for limiting a reception band, wherein the wireless device has a characteristic opposite to a group delay characteristic of the analog bandpass filter. A wireless device, comprising: arithmetic means for performing a filter operation using a digital filter and a reception signal received by its own reception unit. 2. A double superheterodyne wireless device or a wireless device having a plurality of analog bandpass filters for limiting a reception band, wherein each of the plurality of analog bandpass filters has a group delay characteristic or each group. A wireless device comprising: a digital filter having a characteristic opposite to a group delay integrated characteristic obtained by aggregating delay characteristics; and arithmetic means for performing a filter operation using a received signal received by its own receiving unit. . 3. The storage device according to claim 1, further comprising a storage unit configured to store a coefficient of the digital filter, wherein the calculation unit performs a filter calculation based on the digital filter extracted from the storage unit. A wireless device according to claim 1. 4. The storage means includes coefficients of a plurality of digital filters having different characteristics, and selection means for selecting an optimum coefficient of the digital filter from the storage means. The wireless device according to claim 3, wherein a filter operation is performed based on a coefficient of the selected digital filter. 5. Estimating means for estimating a coefficient of a digital filter having an inverse characteristic of a group delay characteristic from an input / output signal or an output signal of an arbitrary analog band-pass filter; The wireless device according to claim 4, wherein the group delay characteristic is corrected using the digital filter obtained. 6. The method according to claim 1, wherein the selection unit includes a switching unit that selectively switches between a coefficient of the digital filter previously stored in the storage unit and a coefficient of the digital filter estimated by the estimation unit. The wireless device according to claim 5. 7. The filter according to claim 1, wherein the arithmetic unit uses a digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter and a reception signal received by a reception unit of a wireless device to perform a filter by complex arithmetic. The wireless device according to claim 1, wherein the wireless device performs an operation. 8. The method according to claim 1, wherein the calculating unit calculates a real number using a real part coefficient of a digital filter having a characteristic opposite to a group delay characteristic of the analog bandpass filter and a reception signal received by a reception unit of the wireless device. The wireless device according to claim 1, wherein a filter operation is performed by an operation. 9. The arithmetic unit convolves a digital filter having a characteristic opposite to the group delay characteristic of the analog bandpass filter with an existing digital filter, and receives the convolved digital filter and a receiving unit of a wireless device. The wireless device according to claim 1, wherein a filter operation is performed using the received signal. 10. The radio apparatus according to claim 9, wherein the existing digital filter is a Nyquist filter, and the correction processing of the group delay characteristic and the correction processing of the Nyquist filter are performed simultaneously. 11. A filter, comprising: performing a complex operation using a digital filter having a characteristic opposite to a group delay characteristic of the analog bandpass filter and a reception signal received by a reception unit of a wireless device; 7. The wireless device according to claim 1, further comprising an arithmetic processing selecting means for selectively switching between a processing for performing an arithmetic operation and a processing for performing a filter operation by performing a real number arithmetic operation. .