JP2007201729A - Adaptive equalizer and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compensate signal distortion with high precision by a short known system without depending on a carrier phase and amplitude of an input signal in an adaptive equalizer adapted under multipath environment. <P>SOLUTION: The adaptive equalizer has a phase compensation means 9 for estimating the carrier phase of the input signal in input of a known signal and outputting a compensation signal in which the phase is compensated so as to cancel the estimated carrier phase and a transversal filter 10 for outputting an addition result after weighting a preliminarily estimated tap coefficient by every individual tap to the output signal of the phase compensation means 9 as an equalizing signal. Furthermore, the adaptive equalizer has a tap coefficient estimation means 14 for updating the tap coefficient by using a predetermined synchronizing signal as reference timing and using an error signal between the output signal (equalizing signal) of the transversal filter 10 and a known replica signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adaptive equalizer and a receiving apparatus, and more particularly, an adaptive equalizer that corrects signal distortion with high accuracy using a short known sequence, and outputs high-quality demodulated data using the adaptive equalizer. It is related with the receiver which performs.

  In recent years, in mobile communication systems and satellite communication systems, technical studies for overcoming frequency selective fading, which is a major limitation in increasing the data transmission speed in a multipath environment, have become active.

  An adaptive equalizer is one of the techniques for overcoming frequency selective fading, and corrects signal distortion caused by frequency selective fading to enable acquisition of high-quality demodulated data. For this reason, in a communication system applied under the multipath environment as described above, a system configuration using an adaptive equalizer is often employed.

  For example, the following Non-Patent Document 1 shows the configuration of an adaptive equalizer according to the related art. In the adaptive equalizer shown in this document, an error signal between an output signal (equalized signal) from a transversal filter that is also its own output and a replica signal (known signal held inside itself) is used, and an LMS is used. A technique for estimating an appropriate tap coefficient in the transversal filter by updating the tap coefficient of the transversal filter so as to reduce the signal distortion using the (Least Mean Square) algorithm is disclosed. Therefore, if this type of adaptive equalizer is used in a receiving apparatus, demodulation can be performed using an equalized signal with reduced signal distortion, and thus higher-quality demodulated data can be output.

Simon Haykin, Translated by Miki Takebe, “Introduction to Adaptive Filters”, Chapter 4, Hyundai Kogakusha

  However, in the conventional technique disclosed in Non-Patent Document 1, for example, when the carrier phase and amplitude of the signal input to the equalizer are significantly different from those of the replica signal, the tap coefficient estimation for correcting the signal distortion is often performed. Therefore, there is a problem in that an appropriate tap coefficient cannot be estimated within a time during which a known signal having a predetermined number of symbols is received, and the demodulation characteristics may be deteriorated.

  The present invention has been made in view of the above, and it is an object of the present invention to provide an adaptive equalizer capable of correcting signal distortion with high accuracy with a short known sequence without depending on the carrier phase or amplitude of an input signal. Objective. It is another object of the present invention to provide a receiving apparatus capable of outputting high-quality demodulated data in a wireless communication system using a short known sequence by applying this adaptive equalizer.

  In order to solve the above-described problems and achieve the object, an adaptive equalizer according to the present invention is a modulation signal having a data format including a known signal. An input signal correction unit that estimates a predetermined parameter of the signal and outputs a correction signal corrected based on the estimated predetermined parameter, and a tap coefficient estimated in advance for each of the output signals of the input signal correction unit A transversal filter that outputs the addition result after weighting for each tap as an equalized signal, a predetermined synchronization signal is used as a reference timing, and an equalized signal that is an output signal of the transversal filter and a replica of the known signal The tap coefficient is updated using a predetermined sequential tap coefficient estimation algorithm for an error signal from the signal. Characterized by comprising a coefficient estimation means.

  The adaptive equalizer according to the present invention equalizes the input signal correction means that enables the output of a correction signal corrected based on predetermined parameters (carrier phase, average amplitude, etc.) estimated for the input signal. Since it is configured to be provided in the previous stage of the processing unit that generates and outputs the signal, an effect that the signal distortion included in the received signal can be corrected with high accuracy even when a short known sequence is used is obtained.

  Embodiments of an adaptive equalizer and a receiving apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
First, in the first embodiment, for example, a carrier phase is estimated from a unique word that is a known sequence for an input signal that has been modulated by PSK (Phase Shift Keying) or QAM (Quadrature Amplitude Modulation), and this estimated carrier phase. The configuration and operation of an adaptive equalizer that corrects signal distortion with high accuracy by using a short known sequence by correcting signal distortion for a signal whose phase has been corrected by this amount will be described.

  FIG. 1 is a diagram of a configuration example of an adaptive equalizer according to the first embodiment of the present invention. An adaptive equalizer 1 shown in FIG. 1 has, as its main component, a transversal filter 10 that outputs an equalized signal that is also its own output signal and has reduced signal distortion and signal loss (attenuation), and a transformer. Input signal correction means 9 for correcting an input signal to the versatile filter 10 into a suitable signal state, and tap coefficient estimation means 14 for estimating an appropriate tap coefficient to be given to the transversal filter 10 are provided. Moreover, as each detailed configuration, the transversal filter 10 includes (N−1) (N is a natural number) delay units 11, N multipliers 12, and one adder 13 which are first delay units. The input signal correcting unit 9 includes each component of a modulation component removing unit 15, an averaging unit 16, a delay unit 17 serving as a second delay unit, and a phase correcting unit 18.

  Next, the operation of the adaptive equalizer according to the first embodiment shown in FIG. 1 will be described. 2 is a diagram illustrating an example of an operation timing chart of the adaptive equalizer according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating FIG. 2 of the adaptive equalizer according to the first embodiment. It is a figure which shows an example of a different operation | movement timing chart. The following description is based on the assumption that a signal having a data format in which a unique word (UW) that is a known sequence is added to the beginning of a slot is received as shown in FIGS.

  In the input signal correction means 9 of the adaptive equalizer 1 shown in FIG. 1, the modulation component removal means 15 uses the slot synchronization pulse (see FIG. 2) as a reference timing, and the input signal is in the period of the unique word (UW). Outputs an unmodulated signal obtained by removing the modulation component from the input signal. Here, both the input signal and the unmodulated signal have complex values.

  Similar to the modulation component removal unit 15, the averaging unit 16 uses the slot synchronization pulse as a reference timing, and the modulation component removal unit only for a predetermined period within a period in which the input signal is a unique word (UW). By averaging the unmodulated signal output from 15, an unmodulated signal having a high signal-to-noise ratio is output. Note that an unmodulated signal having a high signal-to-noise ratio is also a signal having a complex value, like the input signal and the unmodulated signal.

  The delay unit 17 can correct the deviation angle of the non-modulated signal having a high signal-to-noise ratio output from the averaging means 16 from the head of the slot used to calculate the deviation angle in the phase correction means 18 described later. The input signal is output after being delayed by a predetermined time.

  The phase correction unit 18 delays the signal output from the delay unit 17 in the opposite direction by the amount of the deviation angle of the non-modulated signal having a high signal-to-noise ratio output from the averaging unit 16 (the direction that is delayed when the deviation angle is advanced). In this case, by rotating the phase in the traveling direction), a signal in which the carrier phase of the input signal is corrected is generated and output. Note that the output signal of the phase correction means 18 is also a signal having a complex value, like the above-described output signals.

On the other hand, the transversal filter 10 configured as an N-tap transversal filter as described above outputs (N−1) pieces of output signals from the phase correction unit 18 of the input signal correction unit 9 and the delay unit 11. , Each of the complex tap coefficients {W _{0, n} , W _{1, n} ,..., W _{N−2, n} , W _{N−1, n} } output from the tap coefficient estimating means 14 is individually provided. And an equalized signal having a complex value obtained by adding all the N multiplication results is generated and output.

Note that the tap coefficient estimation means 14 uses the slot synchronization pulse as a reference timing as in the conventional adaptive equalizer, and when a unique word (UW) that is a known signal is input, An error signal between the equalized signal that is an output signal and a replica signal (a known signal held inside the equalizer) is used, and the tap coefficient {W of the transversal filter 10 is used using, for example, an LMS (Least Mean Square) algorithm. _{0, n} , W _{1, n} ,..., W _{N−2, n} , W _{N−1, n} } are updated so as to reduce the signal distortion (n is a discrete time and an integer value). However, since the phase amount to be corrected by the phase correcting means 18 changes in slot units, tap coefficients {W _{0, n} , W _{1, n} ,..., W _{N−2, n} , W _N−1 at the head of the slot _{. n} } is preferably set to a predetermined initial value.

  As described above, in the adaptive equalizer 1 of the first embodiment, the phase correction unit 18 of the input signal correction unit 9 performs phase correction, so that the tap coefficient estimation output from the transversal filter 10 is performed. The equalization signal for operating the means 14 is controlled so that an error from the replica signal becomes small from the initial timing when the tap coefficient estimating means 14 is operated, and depends on the carrier phase of the input signal. Therefore, signal distortion can be corrected with high accuracy even for a short known sequence.

  In the above example, the case where the LMS algorithm is used as the tap coefficient estimation algorithm in the tap coefficient estimation means 14 has been described as an example. However, the tap coefficient is updated using another sequential algorithm such as RLS (Recursive Last Square). May be.

In the above description, as an input signal for estimating or updating the tap coefficients {W _{0, n} , W _{1, n} ,..., W _{N−2, n} , W _{N−1, n} }, a unique word ( The case where a UW) is input has been described. However, when a data format in which a pilot symbol (PI) is inserted as shown in FIG. 3 is input, only when a unique word (UW) is input. Alternatively, the tap coefficient may be updated using a pilot symbol (PI) that is a known signal inserted in the middle of the slot. By using such a pilot symbol (PI), it is possible to update the tap coefficient even in the middle of the slot, and it is possible to correct the signal distortion with high accuracy even in a fading transmission line with a fast time variation. It becomes possible.

  As described above, according to the adaptive equalizer of this embodiment, when a modulated signal including a known sequence is input, the carrier phase of the input signal is estimated and the phase correction is performed so as to cancel the estimated carrier phase. Since the correction signal is output, the signal distortion can be corrected with high accuracy even for a short known sequence without depending on the carrier phase of the input signal.

Embodiment 2. FIG.
Next, in the second embodiment, for example, for an input signal that has been subjected to PSK modulation or QAM modulation, the amplitude of the input signal is estimated from a unique word that is a known sequence, and the signal is amplitude-corrected by this estimated amplitude. On the other hand, the configuration and operation of an adaptive equalizer that corrects signal distortion with high accuracy with a short known sequence by correcting signal distortion will be described.

  FIG. 4 is a diagram illustrating a configuration example of an adaptive equalizer according to the second embodiment of the present invention, and includes an amplitude correction unit 20 instead of the configuration of the phase correction unit 18 of the first embodiment. It is composed. Other configurations are the same as those in the first embodiment described above, and the same or equivalent components as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted. The explanation will focus on the two specific operations.

  In the input signal correcting unit 9a of the adaptive equalizer 1a shown in FIG. 4, the amplitude correcting unit 20 converts the delayed input signal output from the delay unit 17 into a high signal-to-noise ratio unmodulated signal output from the averaging unit 16. By multiplying by a predetermined value proportional to the inverse of the average amplitude, a signal (complex signal) whose amplitude is corrected so as to be close to a predetermined average amplitude value is generated and output.

  As described above, in the adaptive equalizer 1a according to the second embodiment, the amplitude correction unit 20 of the input signal correction unit 9a performs amplitude correction. Therefore, the tap coefficient estimation output from the transversal filter 10 is performed. The equalization signal for operating the means 14 is controlled so as to reduce the error from the replica signal from the initial timing at which the tap coefficient estimating means 14 is operated, and does not depend on the signal amplitude of the input signal. Even with a short known sequence, signal distortion can be corrected with high accuracy.

  When a data format in which pilot symbols (PI) are inserted as shown in FIG. 3 is input, a unique word (UW) is input as in the adaptive equalizer of the first embodiment. The tap coefficient may be updated using a pilot symbol (PI) which is a known signal inserted in the middle of the slot. By using such a pilot symbol (PI), it is possible to update the tap coefficient even in the middle of the slot, and it is possible to correct the signal distortion with high accuracy even in a fading transmission line with a fast time variation. Become.

  As in the first embodiment, the tap coefficient may be updated using another sequential algorithm such as RLS other than the LMS algorithm as the tap coefficient estimation algorithm in the tap coefficient estimation unit 14.

  As described above, according to the adaptive equalizer of this embodiment, when a modulated signal including a known sequence is input, the average amplitude of the input signal is estimated and the estimated average amplitude is determined in advance. Since the correction signal whose amplitude is corrected to be close to the average amplitude value is output, the signal distortion can be corrected with high accuracy even for a short known series without depending on the signal amplitude of the input signal. It becomes possible.

Embodiment 3 FIG.
Subsequently, in Embodiment 3, for example, for a PSK modulated or QAM modulated input signal, the carrier phase and amplitude of the input signal are estimated from a unique word that is a known sequence, and the estimated carrier phase and amplitude are separated. Only the configuration and operation of the adaptive equalizer that corrects the signal distortion with high accuracy with a short known sequence by correcting the signal distortion with respect to the signal whose phase and amplitude are corrected respectively.

  FIG. 5 is a diagram showing a configuration example of an adaptive equalizer according to the third embodiment of the present invention. Both functions of the phase correction unit 18 of the first embodiment and the amplitude correction unit 20 of the second embodiment are shown. The phase / amplitude correction means 30 is provided. Other configurations are the same as those in the first or second embodiment, and the same or equivalent components are denoted by the same reference numerals and the description thereof is omitted. In the following, the specific operation of the third embodiment is described. The explanation will be focused on.

  In the input signal correction unit 9b of the adaptive equalizer 1b shown in FIG. 5, the phase / amplitude correction unit 30 converts the delayed input signal output from the delay unit 17 into a high signal-to-noise ratio output from the averaging unit 16. Amplitude correction by multiplying a predetermined value proportional to the reciprocal of the average amplitude of the modulation signal, and phase correction that rotates the phase in the opposite direction by the deviation angle of the high signal-to-noise ratio unmodulated signal output from the averaging means 16 And generate and output an output signal (complex signal) implemented.

  As described above, in the adaptive equalizer 1b of the third embodiment, the phase / amplitude correction unit 30 of the input signal correction unit 9b performs phase correction and amplitude correction, so that the output from the transversal filter 10 is performed. Thus, the equalized signal for operating the tap coefficient estimating means 14 is controlled so that the error from the replica signal becomes small from the initial timing when the tap coefficient estimating means 14 is operated. It is possible to correct the signal distortion with high accuracy even for a short known sequence without depending on the signal amplitude.

  In the case of having a data format in which a pilot symbol (PI) as shown in FIG. 3 is inserted, only when a unique word (UW) is input, as in the adaptive equalizer of the first embodiment. Instead, the tap coefficient may be updated using a pilot symbol (PI) which is a known signal inserted in the middle of the slot. By using such a pilot symbol (PI), it is possible to correct signal distortion with higher accuracy even in a fading transmission line with a fast time variation.

  As in the first and second embodiments, the tap coefficient may be updated using another sequential algorithm such as RLS other than the LMS algorithm as the tap coefficient estimation algorithm in the tap coefficient estimation unit 14.

  As described above, according to the adaptive equalizer of this embodiment, when a modulated signal including a known sequence is input, the carrier phase and average amplitude of the input signal are estimated, and the estimated carrier phase is canceled out. Since a correction signal is output that is phase-corrected and amplitude-corrected so that the estimated average amplitude is close to a predetermined average amplitude value, it depends on the carrier phase and signal amplitude of the input signal. Therefore, signal distortion can be corrected with high accuracy even for a short known sequence.

Embodiment 4 FIG.
Subsequently, in the fourth embodiment, based on the tap coefficient control signal (having two or more types of values) input from the outside, including any of the adaptive equalizers of the first to third embodiments, By making the number of taps actually used variable and fixing tap coefficients of unused taps to zero, the tap coefficients used are adaptively operated with the number of taps suitable for the transmission path, so that the higher the length of a shorter known sequence, the higher the number of taps used. The configuration and operation of an adaptive equalizer that corrects signal distortion with high accuracy will be described.

  FIG. 6 is a diagram showing a configuration example of an adaptive equalizer according to the fourth embodiment of the present invention. In the adaptive equalizer 1 of the first embodiment shown in FIG. The tap coefficient control signal from the outside is input, and the number of taps actually used is changed to be variable. Other configurations are the same as those of the first embodiment, and the same or equivalent components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. The operation will be mainly described.

  In FIG. 6, an external tap coefficient control signal is input to the tap coefficient estimation means 40 of the adaptive equalizer 1c. The tap coefficient estimating means 40 to which the tap coefficient control signal is input always sets the tap coefficient of the tap determined in advance to zero, and updates only the tap coefficient to be used using, for example, the LMS algorithm.

  As described above, the adaptive equalizer 1c according to the fourth embodiment operates by setting the tap coefficient control signal value suitable for the delay spread of the transmission path from the outside and setting the tap coefficients of unused taps to zero. Since the number of taps is appropriately controlled, signal distortion can be corrected with higher accuracy with a shorter known sequence as compared with the adaptive equalizer of the first embodiment.

  In the fourth embodiment, an example in which the configuration in which the number of taps actually used is variable based on a tap coefficient control signal input from the outside is applied to the first embodiment is described as an example. The present invention can also be applied to each of the second and third embodiments, and effects unique to the respective embodiments can also be obtained.

  Further, the tap coefficient estimation unit 40 has been described by way of example using the LMS algorithm, but the tap coefficient may be updated using another sequential algorithm such as RLS.

  As described above, according to the adaptive equalizer of this embodiment, the tap number of taps to be used is variably controlled by setting the tap coefficient of unused taps to zero based on an externally input tap coefficient control signal. As a result, signal distortion can be corrected with higher accuracy using a shorter known sequence, and the processing speed can be improved.

Embodiment 5 FIG.
On the other hand, in the fifth embodiment, instead of inputting a tap coefficient control signal (having two or more kinds of values) from the outside, the tap coefficient control signal estimated by the transmission path estimation means based on the input signal is used. The configuration and operation of the adaptive equalizer used will be described. In the present embodiment, as in the fourth embodiment, the number of taps that are actually used is variable and the tap coefficients of unused taps are fixed to zero, while the tap coefficients that are used are suitable for the transmission line. By performing the adaptive operation with the number of taps, a function of correcting the signal distortion with higher accuracy with a shorter known sequence is provided.

  FIG. 7 is a diagram illustrating a configuration example of an adaptive equalizer according to the fifth embodiment of the present invention. In the configuration of the adaptive equalizer according to the fourth embodiment, tap coefficient control to the tap coefficient estimation unit 40 is illustrated. A transmission path estimation means 50 for generating and outputting a signal based on an input signal is provided. Other configurations are the same as those in the above-described fourth embodiment, and the same or equivalent components as those in the fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted. The explanation will focus on the 5 specific operations.

  In the adaptive equalizer 1d shown in FIG. 7, the transmission path estimation means 50 uses the slot synchronization pulse as a reference timing, and matches the input signal when a unique word (UW) that is a known signal is input. By performing correlation calculation using a filter or the like, the delay spread of the transmission path is estimated. Then, a tap coefficient control signal value suitable for the estimated delay spread is selected and output.

  Further, the tap coefficient estimation means 40, as in the fourth embodiment, always fixes the tap coefficient of the tap previously determined by the tap coefficient control signal to zero while only using the tap coefficient to be used, for example, the LMS algorithm. Update using.

  As described above, the adaptive equalizer 1d according to the fifth embodiment calculates the value of the tap coefficient control signal suitable for the delay spread estimated based on the input signal, and does not use it based on the calculated tap coefficient control signal. Since the tap coefficient of taps is set to zero and the number of taps to be operated is controlled appropriately, signal distortion can be corrected with high accuracy with a short known sequence even when the delay spread of the transmission path fluctuates. It becomes possible.

  Although the tap coefficient estimating unit 40 has been described using the LMS algorithm, the tap coefficient may be updated using another sequential algorithm as in the other embodiments.

  In addition, although the transmission path estimation means 50 has shown a technique for estimating a delay spread by obtaining a correlation operation for a unique word (UW) that is a known signal, a technique for estimating another delay spread from an input signal is shown. The tap coefficient control signal may be generated appropriately from the input signal.

Moreover, FIG. 8 is a figure which shows the other structural example different from FIG. 7 of the adaptive equalizer concerning Embodiment 5 of this invention. In the transmission path estimation means 50 shown in FIG. 7, the method of generating the tap coefficient control signal based on the input signal has been shown, but as shown in FIG. 8, the past tap coefficients {output from the tap coefficient estimation means 40 { Tap coefficient control signals may be generated based on W _{0, n} , W _{1, n} ,..., W _{N−2, n} , W _{N−1, n} }. In this case, similar to the adaptive equalizer 1d shown in FIG. 7, even when the delay spread of the transmission path varies, the effect of correcting the signal distortion with high accuracy with a short known sequence can be obtained. Further, in the adaptive equalizer 1e shown in FIG. 8, since the correlation calculation in the transmission path estimation means 50a is not required, an effect that the circuit scale can be reduced can be obtained.

  As described above, according to the adaptive equalizer of this embodiment, based on the tap coefficient control signal generated inside itself, the tap coefficient of taps to be used is variably controlled by setting the tap coefficient of unused taps to zero. Thus, even when the delay spread of the transmission path varies, it is possible to correct the signal distortion with high accuracy with a short known sequence.

  Further, according to the adaptive equalizer of this embodiment, since the tap coefficient control signal can be generated and output based on the past tap coefficient, a part of the correlation calculation processing necessary for generating the tap coefficient control signal is also provided. Alternatively, all of them can be made unnecessary, and the circuit scale can be further reduced.

Embodiment 6 FIG.
Subsequently, in the sixth embodiment, for example, the use of a short known sequence is required by using any of the adaptive equalizers of the first to fifth embodiments for an input signal subjected to PSK modulation or QAM modulation. A configuration and operation of a receiving apparatus that enables output of high-quality demodulated data in a wireless communication system will be described.

  FIG. 9 is a diagram of a configuration example of a receiving apparatus according to the sixth embodiment of the present invention. The receiving apparatus shown in FIG. 9 has a quasi-synchronous detection means connected to the receiving antenna 60 on the input side of the adaptive equalizer 1 centering on the adaptive equalizer 1 according to the first embodiment shown in FIG. 61, automatic gain control (AGC) means 62 for outputting a gain control signal for controlling the gain of the quasi-synchronous detection means 61, and bit timing recovery using the output of the quasi-synchronous detection means 61 as an input signal (BTR: Bit Timing Recovery) means 63, slot synchronization means 64 and automatic frequency control (AFC) means 65 using the output of bit timing recovery means 63 as input signals, and adaptation, etc. Data determination means 66 is provided on the output side of the generator 1. The output of the slot synchronization means 64 is input to each of the automatic frequency control means 65, the adaptive equalizer 1 and the data determination means 66.

  Next, the operation of the receiving apparatus according to the sixth embodiment shown in FIG. 9 will be described. In FIG. 9, the quasi-synchronous detection means 61 outputs a baseband signal (complex signal) obtained by performing quasi-synchronous detection and analog-digital conversion at a predetermined rate on the signal received by the receiving antenna 60. . The quasi-synchronous detection means 61 also performs gain correction of the received signal based on a gain control signal output from an automatic gain control means 62 described later.

  The automatic gain control means 62 observes the power of the baseband signal and generates a gain control signal so that the observed power value becomes a predetermined value. The bit timing reproduction means 63 estimates the timing of the Nyquist point from the baseband signal, is synchronized with the timing of the Nyquist point, and is resampled at a rate M times the symbol rate (M is a natural number). A playback baseband signal that is a band signal is output.

  The slot synchronization means 64 performs a correlation operation between the reproduction baseband signal and the unique word (UW) replica signal, and generates a slot synchronization pulse at a timing when the correlation value becomes larger than a predetermined threshold value. .

  The automatic frequency control means 65 estimates the frequency deviation based on the phase rotation amount of the reproduction baseband signal output from the bit timing reproduction means 63 for a predetermined period, and calculates the estimated frequency deviation for this reproduction baseband signal. By performing phase rotation so as to cancel, a frequency deviation corrected baseband signal (complex signal) is generated and output to the adaptive equalizer 1. When processing a known signal such as a unique word (UW) or a pilot symbol (PI), the automatic frequency control means 65 uses the slot synchronization pulse output from the slot synchronization means 64 as a reference timing for these known signals. The frequency deviation may be estimated with high accuracy by removing the modulation component using a replica of the signal.

  The adaptive equalizer 1 is the same as that shown in Embodiment 1, and generates a highly accurate equalized signal (complex signal) by performing adaptive equalization using a frequency deviation corrected baseband signal as an input signal. Output.

  The data determination unit 66 outputs high-quality demodulated data by performing data demodulation on the highly accurate equalized signal output from the adaptive equalizer 1 using a determination method corresponding to the modulation method. .

  As described above, in the receiving apparatus according to the sixth embodiment, by applying the adaptive equalizer 1 described in the first embodiment, it is possible to generate a highly accurate equalized signal and And high-quality demodulated data can be generated.

  FIG. 10 is a diagram illustrating another configuration example different from FIG. 9 of the receiving apparatus according to the sixth embodiment of the present invention. In the receiving apparatus shown in FIG. 9, the equalized signal output from the adaptive equalizer 1 is directly input to the data determining unit 66, but the equalized signal is input to the carrier reproducing unit 67 as shown in FIG. After that, the data may be input to the data determination means 66. In this case, even when the adaptive equalizer 1 is not operating, the carrier reproduction means 67 can follow the carrier phase, so that higher quality demodulated data can be obtained.

  In the sixth embodiment, the configuration of a receiving apparatus that generates high-quality demodulated data using the adaptive equalizer 1 described in the first embodiment has been described. The adaptive equalizers 1a to 1e shown in the forms 2 to 5 can be applied, and the same effects as those of the present embodiment can be obtained.

  As described above, according to the receiving apparatus of this embodiment, since it is configured using the adaptive equalizer shown in Embodiments 1 to 5, using a more accurate equalization signal, High quality demodulated data can be output.

  Further, according to the receiving apparatus of this embodiment, if the carrier phase is followed by the carrier reproducing means before demodulating the equalized signal, higher quality demodulated data can be obtained.

  As described above, the adaptive equalizer and receiving apparatus according to the present invention are useful as an adaptive equalizer and receiving apparatus that correct signal distortion with high accuracy with a short known sequence.

It is a figure which shows one structural example of the adaptive equalizer concerning Embodiment 1 of this invention. It is a figure which shows an example of the operation | movement timing chart of the adaptive equalizer concerning Embodiment 1 of invention. FIG. 3 is a diagram showing an example of an operation timing chart different from FIG. 2 of the adaptive equalizer according to the first exemplary embodiment; It is a figure which shows one structural example of the adaptive equalizer concerning Embodiment 2 of this invention. It is a figure which shows one structural example of the adaptive equalizer concerning Embodiment 3 of this invention. It is a figure which shows one structural example of the adaptive equalizer concerning Embodiment 4 of this invention. It is a figure which shows one structural example of the adaptive equalizer concerning Embodiment 5 of this invention. It is a figure which shows the other structural example different from FIG. 7 of the adaptive equalizer concerning Embodiment 5 of this invention. It is a figure which shows the example of 1 structure of the receiver concerning Embodiment 6 of this invention. It is a figure which shows the other structural example different from FIG. 9 of the receiver concerning Embodiment 6 of this invention.

Explanation of symbols

1, 1a, 1b, 1c, 1d, 1e Adaptive equalizer 9, 9a, 9b Input signal correction means 10 Transversal filter 11, 17 Delayer 12 Multiplier 13 Adder 14 Tap coefficient estimation means 15 Modulation component removal means 16 Averaging means 18 Phase correction means 20 Amplitude correction means 30 Phase / amplitude correction means 40 Tap coefficient estimation means 50, 50a Transmission path estimation means 60 Reception antenna 61 Quasi-synchronous detection means 62 Automatic gain control means 63 Bit timing recovery means 64 Slot synchronization Means 65 Automatic frequency control means 66 Data judgment means 67 Carrier regeneration means

Claims (10)

For a modulated signal having a data format including a known signal, a predetermined parameter of the modulated signal including the known signal is estimated when the modulated signal is input, and a correction signal corrected based on the estimated predetermined parameter is output. Input signal correction means;
A transversal filter that outputs, as an equalized signal, an addition result after weighting the tap coefficient estimated in advance for each individual tap with respect to the output signal of the input signal correcting means;
The tap signal is used by using a predetermined sequential tap coefficient estimation algorithm for an error signal between an equalization signal that is an output signal of the transversal filter and a replica signal of the known signal, using a predetermined synchronization signal as a reference timing. Tap coefficient estimation means for updating the coefficient;
An adaptive equalizer characterized by comprising:   The input signal correction means estimates a carrier phase of the input signal as the predetermined parameter and outputs a correction signal that is phase-corrected so as to cancel the estimated carrier phase when a modulation signal including the known signal is input. The adaptive equalizer according to claim 1, further comprising a correction unit.   The input signal correcting unit estimates an average amplitude of the input signal as the predetermined parameter when a modulated signal including the known signal is input, and is close to a predetermined average amplitude value with respect to the estimated average amplitude. 2. The adaptive equalizer according to claim 1, further comprising amplitude correction means for outputting a correction signal subjected to amplitude correction as described above.   The input signal correction means estimates a carrier phase and an average amplitude of the input signal as the predetermined parameter when inputting a modulation signal including the known signal, corrects the phase so as to cancel the estimated carrier phase, and 2. The adaptive equalization according to claim 1, further comprising phase / amplitude correction means for outputting a correction signal whose amplitude is corrected to be close to a predetermined average amplitude value with respect to the estimated average amplitude. vessel.   5. The tap coefficient estimating means variably controls the number of taps to be used based on a tap coefficient control signal input from the outside with zero tap coefficients of unused taps. The adaptive equalizer as described in any one. Further comprising transmission path estimation means for estimating the delay spread of the transmission path from the input signal and generating and outputting a tap coefficient control signal corresponding to the estimated delay spread;
The tap coefficient estimating means variably controls the number of taps to be used with zero tap coefficients of unused taps based on a tap coefficient control signal output from the transmission path estimating means. The adaptive equalizer as described in any one of 1-4.   The adaptive equalizer according to claim 6, wherein the transmission path estimation means generates and outputs the tap coefficient control signal based on a past tap coefficient output from the tap coefficient estimation means. The data format of the known signal includes a unique word and a pilot symbol,
The adaptive equalization according to any one of claims 1 to 7, wherein the tap coefficient estimating means updates the tap coefficient when the pilot symbol is input in addition to the input of the unique word. vessel. A modulated signal having a data format including a known signal is received, a timing to be a Nyquist point is estimated from a baseband signal obtained by detecting the modulated signal, and the symbol rate is synchronized with the timing of the Nyquist point. A bit timing reproduction means for generating a reproduction baseband signal resampled at a rate of M times (M is a natural number);
Synchronizing means for performing a correlation operation between the reproduction baseband signal and the replica signal of the known signal, and generating a synchronization pulse at a timing when the correlation value obtained by performing the correlation operation is greater than a predetermined threshold value;
9. The reproduction baseband signal is input, and an equalized signal obtained by performing equalization processing on the reproduction baseband signal based on a synchronization pulse output from the synchronization unit is output. The adaptive equalizer described, and
A data determination unit that receives the equalized signal and outputs demodulated data obtained by performing data demodulation based on a predetermined determination method according to a modulation method of the modulation signal;
A receiving apparatus comprising:   Carrier recovery means for estimating a carrier phase using the equalized signal and outputting a signal whose phase is corrected so as to cancel the estimated carrier phase is provided between the adaptive equalizer and the data determining means. The receiving device according to claim 9.

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