JPH11308289A - Demodulator and radio communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable demodulation processing to be appropriately controlled and to attain improve reception performance even when a fluctuation in a reception signal level is vigorous by deciding a control correction value for correcting processing of a demodulation processing means in accordance with statistic information which statistically processes plural reception signal level values. SOLUTION: A reception level statistical processing part 9 stores a reception signal level value S7 for a specified time, statistically processes plural reception level values S7 and calculates a fluctuating reception signal level S10 for indicating a temporal change at the reception signal level S7. A fading decision part 10 decides state of fading on the basis of the fluctuating reception signal level S10 and outputs a fading decision value S11 in accordance with the decision result as statistical information. A corrected value decision part 11 decides a correction value for a control width of a BTR part 5 and an AFC part 7 based on the fading decision part S11 and outputs a BTR control width correction value S12 and an AFC control width correction value S13 in accordance with the correction value respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to demodulation of a received signal, for example, to a demodulator having a symbol clock timing recovery function and an automatic frequency control function, and a radio communication apparatus using the demodulator.

[0002]

2. Description of the Related Art In wireless communication in a mobile communication system, communication is performed between a transmitting side and a receiving side using a symbol clock having the same rate and radio waves having the same frequency. However, in practice, there is a difference between symbol clocks and frequencies between the transmitting side and the receiving side due to individual differences between wireless communication devices.

Further, when the path of wireless communication changes due to movement of the wireless communication device, the phase changes. As described above, a shift in the symbol clock or the frequency may occur due to the change in the phase.

[0004] For this reason, the demodulator of the radio communication apparatus is provided with an automatic frequency control (Auto Frequency Control) for the frequency shift.
trol: Hereinafter, AFC. ) Symbol clock timing recovery (Bi
t Timing Recovery: Hereinafter, referred to as BTR. ) A function is provided so that the receiving side always detects a deviation between the symbol clock and the frequency, and performs control so as to correct the deviation.

FIG. 12 is a block diagram showing a configuration of a conventional demodulator having a BTR function and an AFC function. Here, a case where the demodulator receives a received signal as input and outputs received data, a symbol clock, and a received signal level value will be described.

In FIG. 12, a frequency converter 1 converts a received signal S1 into an IF signal (Integer) according to a local frequency signal.
R2 (rmediate frequency signal: intermediate frequency signal). The phase detection unit 2 outputs an IF based on the symbol clock at a rate n (integer) times the symbol clock.
A phase is detected by sampling the signal S2, and phase data S3 corresponding to the phase is output. The delay detection unit 3 detects a phase difference from the previous symbol from the phase data S3, and outputs phase difference data S4 according to the phase difference. The reception data generator 4 generates reception data S5 from the phase difference data S4 at the timing of the symbol clock.

[0007] The BTR section 5 corrects based on the phase data S3 and reproduces the symbol clock S6. The reception level detector 6 detects the power level of the reception signal from the IF signal S2, and receives a reception signal level value S7 corresponding to the detected power level.
Is output. The AFC unit 7 corrects according to the phase difference data S4 and outputs a control voltage S8 for controlling the generated voltage of the local frequency. The local frequency generator 8 generates a local frequency signal S9 according to the control voltage S8.

FIG. 13 is a block diagram showing a detailed configuration of the BTR unit 5 in FIG. In FIG. 13, the timing detecting section 21 detects a symbol clock timing based on the speed at which the phase changes from the phase data S3, and outputs the detected timing as a timing S21. The timing comparing section 22 compares the timing S21 with the previous timing of the symbol clock S6, and outputs timing deviation data S22 corresponding to the deviation.

The timing correction section 23 determines the direction and width of correcting the symbol clock based on the timing shift data S22, and outputs the corresponding timing correction data S23. The clock reproducing unit 24 performs correction based on the timing correction data S23 and reproduces the symbol clock S6.

FIG. 14 is a block diagram showing a detailed configuration of the AFC unit 7 in FIG. 14, the phase difference comparing section 31 detects a shift between the phase difference data S4 and a reference phase difference, and outputs phase difference shift data S31 according to the shift. The control voltage determination unit 32 determines a direction and a width for correcting the frequency based on the phase difference shift data S31, and outputs a control voltage S8 corresponding thereto.

The operation for correcting and reproducing the symbol clock will be described with reference to FIGS.

The received signal S1 is a local frequency signal S9
Is converted into an IF signal S2 by the frequency conversion unit 1 in accordance with, and is output to the phase detection unit 2. The phase detector 2 outputs an IF according to a symbol clock rate based on the symbol clock S6.
A phase is detected from the signal S2, and one or a plurality of phase data S3 corresponding to the detected phase are output.

When the phase data S3 is input to the BTR unit 5, a symbol clock S6 corrected based on the phase data S3 is reproduced.

In the BTR section, the timing detecting section 21 detects the symbol clock timing based on the speed at which the phase changes from the phase data S3, and outputs the timing S21. Then, the timing comparing section 22 compares the timing S21 with the previous symbol clock S6, thereby outputting timing deviation data S22 corresponding to the deviation, and outputting the timing correction section 23.
Is output to

When the timing shift data S22 is input to the timing correction section 23, the direction of correcting the symbol clock and the width of correction are determined to reduce the shift, and the corresponding timing correction data S23 is output. . When the timing correction data S23 is input to the clock recovery unit 24, the symbol clock S6 corrected based on the timing correction data S23 is reproduced.

Next, the operation for correcting the local frequency will be described with reference to FIGS.

As described above, when the reception signal S1 is converted into the IF signal S2 by the frequency conversion unit 1, the phase detection unit 2 outputs the I signal S1.
A phase is detected from the F signal S2, and one or a plurality of phase data S3 corresponding to the detected phase are output.

When the phase data S3 is input to the delay detection section 3, a phase difference from the previous symbol is detected from the phase data S3, and phase difference data S4 corresponding to the phase difference is output. When the phase difference data S4 is input to the AFC unit 7, a control voltage S8 of the local frequency generator 8 corresponding to the phase difference data S4 is output.

At this time, in the AFC section 7, the phase difference comparing section 3
The shift between the phase difference data S4 input in step 1 and the reference phase difference is detected, and the phase difference shift data S31 corresponding to the shift is output to the control voltage determination unit 32. Then, the control voltage determination unit 32 determines the direction and width for correcting the local frequency based on the phase difference deviation data S31, and outputs a corrected control voltage S8 corresponding to the direction and width.

The control voltage S8 is supplied to the local frequency generator 8
And a corrected local frequency S9 is generated.

As described above, according to the conventional demodulator, B
By correcting the deviation of the symbol clock in the TR unit and the deviation of the frequency in the AFC unit, it is possible to perform communication using the same rate symbol clock and the same frequency on the transmission side and the reception side.

However, in the conventional demodulator as described above,
For example, when the received signal level is low due to the state of the transmission path, there is a problem that it is not possible to appropriately correct a symbol clock or frequency shift.

That is, when the received signal level is small, the ratio of noise to the received signal increases, and the possibility of detecting an erroneous phase increases. The BTR section and the AFC section in the above-described conventional demodulator perform correction based on the phase, so that when an erroneous phase is detected, correction of the frequency and the symbol clock cannot be performed appropriately.

On the other hand, for example, Japanese Patent Application Laid-Open No. 8-288
The automatic frequency control circuit disclosed in Japanese Patent Application Laid-Open No. 796/1992 controls AFC (AFC data) according to the signal quality of a received signal.
Is adjusted to prevent malfunction of the automatic frequency control circuit.

FIG. 15 is a block diagram showing a configuration of an automatic frequency control circuit disclosed in Japanese Patent Application Laid-Open No. 8-288796. In FIG. 15, quadrature demodulation section 101 has a GMSK (Gaussian filtered M) converted to an intermediate frequency signal.
An in-phase signal I, an anti-phase signal Q, and an electric field strength signal RSSI are generated from the signal S100.

The cross-correlation coefficient calculation circuit 102 calculates the cross-correlation of the received signal from the in-phase signal I and the anti-phase signal Q,
Calculate the intersymbol interference amount. The signal quality calculation circuit 103
The inter-symbol interference calculated by the cross-correlation coefficient calculation circuit 102 and the field strength signal RSSI are used as parameters, and the quality of the received signal is determined by a combination of the parameters, and a quality signal in which the quality is quantified is output.

The signal quality determination circuit 104 ranks the quality signals from the signal quality calculation circuit 103 and determines which rank the quality signal is in. The AFC data generation circuit 105 multiplies the AFC data by a coefficient corresponding to the correction amount according to the determination result of the signal quality determination circuit 104, and generates an AFC data signal.

PLL circuit (Phase Lock Loop circuit) 10
6 is based on a correction signal corresponding to the AFC data signal,
The voltage control oscillation circuit 107 is controlled. The voltage controlled oscillation circuit 107 supplies the quadrature demodulation unit 101 with a frequency-divided signal when generating the in-phase signal I and the anti-phase signal Q.

The operation will be described. GMSK signal S1
When 00 is input to the quadrature demodulation unit 101, the in-phase signal I, the anti-phase signal Q, and the field strength signal RSSI are output according to the frequency-divided signal supplied from the voltage controlled oscillation circuit 107.

When the in-phase signal I and the anti-phase signal Q are input to the cross-correlation coefficient calculation circuit 102, the intersymbol interference amount is calculated, and the intersymbol interference amount signal indicating the result is sent to the signal quality calculation circuit 103. Is output. Specifically, the training sequence code (TS) in one burst of the in-phase signal I
C) The middle 16 bits within the bits are shifted, resulting in 11 cross-correlation coefficients. Then, of the 11 cross-correlation coefficients, the sum of 6 cross-correlation coefficients excluding the 5 cross-correlation coefficients having the maximum sum of absolute values is the total of 11 cross-correlation coefficients. , And this numerical value is output to the signal quality calculation circuit 103 as an intersymbol interference amount signal.

Then, the signal quality calculation circuit 103 generates a quality signal in which the quality of the received signal is quantified based on the intersymbol interference amount indicated by the intersymbol interference amount signal and the field strength signal RSSI, and determines the signal quality. The signal is output to the circuit 104. Then, the signal quality determination circuit 104 determines which rank the quality signal is in. In accordance with the determination result, the AFC data generation circuit 105 multiplies the AFC data by a coefficient corresponding to the correction amount, and generates an AFC data signal.

For example, when it is determined that the quality signal is in 7 ranks out of the maximum 10 ranks, a coefficient corresponding to the correction amount of 70% when the signal quality is the best is multiplied by the AFC data, A signal is generated.

When a correction signal corresponding to the AFC data signal is input to the PLL circuit 106, the voltage control oscillation circuit 107 is controlled based on the correction signal, and automatic frequency control is performed.

As described above, according to the conventional frequency automatic control circuit, the signal quality is determined based on the in-phase signal, the negative-phase signal, and the electric field strength signal, and the AFC data indicating the correction amount corresponding to the signal quality is determined. , And automatically controlling the frequency, it is possible to prevent malfunction of the automatic frequency circuit.

[Problems to be solved by the invention]

However, the conventional automatic frequency control circuit has a problem that it is not possible to perform appropriate frequency correction control when the reception level fluctuates greatly. That is, the conventional frequency automatic control circuit controls the frequency correction for the next received signal whose signal quality has been determined, and is effective when the fluctuation of the reception level is gentle. However, when the reception level fluctuates greatly, the reception signal level and the signal quality greatly change between the current reception signal and the next reception signal, so that it is not possible to appropriately control the frequency correction.

Further, since a training sequence code is used when obtaining the intersymbol interference amount, there is a problem that the method can be applied only to a radio communication system including a training sequence code in a signal.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to appropriately control demodulation processing even when the received signal level fluctuates greatly, to improve the receiving performance and Applicable to wireless communication systems,
It is an object to obtain a highly versatile demodulator and a wireless communication device.

[0038]

The demodulator according to the present invention comprises:
Demodulation processing means for demodulating a received signal using a local frequency and outputting received data and a symbol clock;
Receiving level detecting means for detecting the level of the power of the received signal and outputting a received signal level value corresponding to the level, and statistically processing a plurality of received signal level values detected in a predetermined time to obtain 1 or It comprises a reception level statistical processing means for obtaining a plurality of types of statistical information, and a correction determining means for determining a control width correction value for correcting the processing of the demodulation processing means according to one or a plurality of types of statistical information.

Further, in the demodulator according to the next aspect of the present invention, the statistical information is a variable reception signal level representing a temporal variation of a plurality of reception signal level values.

Further, the demodulator according to the next invention is in a fading state in which the statistical information is obtained from a variable received signal level representing a temporal change of a plurality of received signal level values.

In the demodulator according to the next invention, the statistical information is an average received signal level representing an average of a plurality of received signal level values.

In the demodulator according to the next invention, when the correction determining means determines a control width correction value for correcting the processing of the demodulation processing means, the received signal level value at a predetermined time is used.

Also, in the demodulator according to the next invention, the demodulation processing means includes a symbol clock timing reproducing means for reproducing a symbol clock by correcting the phase according to the phase of the received signal. The control width correction value for correcting the control of the timing reproducing means is determined.

Further, in the demodulator according to the next invention, the demodulation processing means includes frequency control means for controlling generation of a local frequency in accordance with the phase of the received signal, and the correction determining means controls the frequency control means. The control width correction value to be corrected is determined.

Further, a radio communication apparatus according to the next invention performs radio communication by modulating and demodulating between a plurality of radio communication apparatuses, and a demodulator demodulates a received signal using a local frequency and performs reception processing. Demodulation processing means for outputting data and a symbol clock; reception level detection means for detecting a power level of a received signal and outputting a received signal level value corresponding to the level; A reception level statistical processing means for statistically processing signal level values to obtain one or more types of statistical information, and a control width correction value for correcting the processing of the demodulation processing means according to the one or more types of statistical information. And a correction determining means.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a wireless communication device according to one embodiment of the present invention. For example, FIG. 1 shows a PHS (Personal Handy).
Phone System).

In FIG. 1, an interface unit A inputs and outputs transmission information or reception information between a radio communication device and a user. For example, it includes a speaker A1, a microphone A2, a key A3, and a display unit A4, and inputs and outputs information such as voices, images, and characters.

The control section B generates transmission data consisting of a 1/0 digital signal from information input from the interface section A at the time of transmission, and receives data consisting of a 1/0 digital signal at the time of reception. , Generates information such as voice, image, text, and received signal strength according to the symbol clock and the received signal level value, and outputs the information to the interface unit A.

The modulation section C modulates transmission data composed of a 1/0 digital signal. The waveform generation unit C1 generates a waveform of an I (in-phase) component and a Q (quadrature) component from the transmission data,
The quadrature modulator C2 modulates the I (in-phase) component and the Q (quadrature) component with π / 4 shift QPSK according to the local frequency output from the synthesizer C3.

The RF unit D up-converts the modulated signal input from the modulation unit C into a radio frequency band at the time of transmission, amplifies the signal, and outputs the amplified signal as a transmission signal. After amplifying the received signal at the time of reception, the signal is down-converted from the radio frequency band and output.

The mixer D1 up-converts the modulated signal input from the modulator C into a radio frequency band according to the local frequency output from the synthesizer D2. The transmission amplifier D3 amplifies a signal in a radio frequency band,
Output as a transmission signal.

The switch D4 switches between transmission and reception. At the time of transmission, the transmission amplifier D3 is connected to the antenna E, and at the time of reception, the antenna E is connected to the reception amplifier D5. The receiving amplifier D5 amplifies the received signal. Mixer D
6 down-converts the amplified received signal according to the local frequency output from the synthesizer D2.

The antenna E transmits and receives a radio signal to and from another radio communication device. The demodulation unit F is a demodulator and receives a down-converted received signal as input and outputs received data, a symbol clock, and a received signal level value.

The operation of the wireless communication device will be described. At the time of transmission, when the user inputs transmission information, the transmission information is output to the control unit B via the interface unit A. For example, when the user transmits the voice, the voice transmitted by the user is output to the control unit B via the microphone A2, and the user can input the voice information. Also, for example, when the user transmits document information, the document transmission information is output to the control unit B via the key A3, and the user can input the document information.

In the control section B, transmission data consisting of a 1/0 digital signal is generated from the transmission information and output to the conversion section C. In the conversion unit C, the waveforms of the I (in-phase) component and the Q (quadrature) component are generated from the transmission data by the waveform generation unit C1, and the π / 4 shift QP is generated by the quadrature modulator C2.
Modulated by SK. For example, a modulated signal in the 240 MHz band is output to the RF unit D.

When the modulated signal is input to the RF unit D,
Up-converted by mixer D1. For example, a local frequency in the 1.66 GHz band is output from the synthesizer D2, and the modulated signal in the 240 MHz band is output as 1.
Up-converted to 9 GHz band. After being amplified by the transmission amplifier D3, the signal is transmitted as a transmission signal from the antenna E, and transmission information from the user can be transmitted.

At the time of reception, when a signal transmitted from another wireless communication device is received by the antenna E,
After being amplified by the receiving amplifier D5, it is down-converted by the mixer D6 and output to the demodulation unit F. For example, a local frequency in the 1.66 GHz band is output from synthesizer D2, and a received signal in the 1.9 GHz band is
Down-converted to 0MHz band.

In the demodulation section F, reception data, a symbol clock and a reception level value are extracted from the reception signal, and output to the control section B. In the control unit B, reception information such as voice, image, text, and the strength of the reception signal is generated from the reception data composed of the 1/0 digital signal according to the symbol clock and the reception signal level value, and output to the interface unit A. You.

For example, voice reception information and character reception information such as electronic mail are generated from received data according to a symbol clock. The information on the strength of the received signal is generated according to the received signal level value.

The reception information generated in this way is output via the interface unit A, and the user can obtain the reception information. For example, audio reception information is output from the speaker A1, and, for example, image and character reception information is output from the display unit A4, so that the user can obtain the reception information.

FIG. 2 is a block diagram showing a configuration of demodulation section F of the wireless communication apparatus shown in FIG.

In FIG. 2, a frequency converter 1 converts a received signal S1 into an IF signal S2 according to a local frequency signal. The phase detector 2 outputs the IF signal S at a rate n (integer) times the symbol clock based on the symbol clock.
2 is sampled to detect a phase, and phase data S3 corresponding to the phase is output. The delay detection unit 3 detects a phase difference from the previous symbol from the phase data S3, and outputs phase difference data S4 according to the phase difference. The reception data generator 4 generates reception data S5 composed of a 1/0 digital signal at the timing of the symbol clock from the phase difference data S4.

The reception level detector 6 detects the power level of the reception signal from the IF signal S2 and outputs a reception signal level value S7 corresponding to the detected power level. The reception level statistic processing unit 9 stores the reception signal level value S7 for a predetermined time, and stores a plurality of reception signal level values S detected at a predetermined time.
7 is statistically processed to calculate a fluctuation reception signal level S10 indicating a temporal fluctuation of the reception signal level value S7. The fading determination unit 10 determines a fading state based on the variable received signal level S10, and outputs a fading determination value S11 according to the determination result as statistical information. The correction value determination unit 11 determines a correction value of the control width of the BTR unit and the AFC unit based on the fading determination value S11 that is statistical information, and calculates a BTR control width correction value S12 and an AFC control width corresponding to the correction value, respectively. The correction value S13 is output.

The BTR unit 5 includes the phase data S3 and the BTR
The symbol clock S6 is reproduced based on the correction based on the control width correction value S12. The AFC unit 7 outputs the phase difference data S4
And a control voltage S8 for controlling the generated voltage of the local frequency, which is corrected according to the AFC control width correction value S13. The local frequency generator 8 generates a local frequency signal S9 according to the control voltage S8.

In the present embodiment, the frequency conversion unit 1, the phase detection unit 2, the delay detection unit 3, the reception data generation unit 4, the BTR unit 5, the AFC unit 7 and the local frequency generation unit 8 And demodulation processing means for demodulating the received signal using the above and outputting received data and a symbol clock.

FIG. 3 is a block diagram showing a detailed configuration of the BTR unit 5 in FIG. In FIG. 3, the timing detecting section 21 detects a symbol clock timing based on the speed at which the phase changes from the phase data S3, and outputs the detected timing as a timing S21. Timing comparison unit 22
Compares the timing S21 with the previous timing of the symbol clock S6, and outputs timing deviation data S22 corresponding to the deviation.

The timing correction unit 23 determines the direction and width of correcting the symbol clock based on the timing shift data S22 and the BTR control width correction value S12 determined by the correction value determination unit 11, and determines the corresponding timing correction data. S23 is output. Clock regeneration unit 24
Recovers the symbol clock S6 by correcting based on the timing correction data S23.

FIG. 4 is a block diagram showing a detailed configuration of the AFC unit 7 in FIG. In FIG. 4, a phase difference comparing section 31 detects a shift between the phase difference data S4 and a reference phase difference, and outputs the phase difference shift data S3 according to the shift.
Outputs 1. The control voltage determination unit 32 determines the phase difference deviation data S31 and the AF determined by the correction value determination unit 11.
Based on the C control width correction value S13, the direction and width for correcting the frequency are determined, and the corresponding control voltage S8 is output.

The operation of the demodulation unit will be described with reference to FIGS. As described above, the demodulation unit receives the received signal down-converted by the RF unit D and receives the received data, the symbol clock, and the received signal level value.
Output to

When the reception signal S1 is input from the RF unit D, the IF signal S2 is output by the frequency conversion unit 1 in accordance with the local frequency S9 generated by the local frequency generation unit 8.
And output to the phase detector 2. And BT
In accordance with the symbol clock rate based on the symbol clock S6 reproduced by the R section 5, the phase detection section 2 detects a phase from the IF signal S2, and outputs one or a plurality of phase data S3 corresponding to the detected phase. Is done. For example, when the IF signal S2 is sampled at a rate n times the symbol clock, n pieces of phase data are output during one symbol period.

When the phase data S3 is input to the delay detection unit 3, a phase difference from the previous symbol is detected from the phase data S3, and phase difference data S4 corresponding to the phase difference is output. Then, the reception data generation unit 4 converts the phase difference data S4 into the reception data S5 at the timing of the symbol clock S6.
Is generated, and the received data S5 is output to the control unit B.

On the other hand, in the BTR unit 5, the symbol clock S6 corrected based on the phase data S3 and the BTR control width correction value S12 is reproduced, and the symbol clock S6 is output to the control unit B. In addition, the reception level detection unit 6 detects the power level of the reception signal from the IF signal S2, and outputs a reception signal level value S7 corresponding to the level to the control unit B. In this manner, the demodulation unit F can generate the reception data S5, the symbol clock S6, and the reception signal level value S7 from the reception signal S1, and output them to the control unit B.

Next, a description will be given of the operation when correcting and reproducing the symbol clock. For example, from the plurality of reception signal level values S7 detected at regular time intervals by the reception level detection unit 6, the reception level statistic processing unit 9 performs statistical processing to perform fluctuation processing indicating the temporal fluctuation of the reception signal level value S7. The signal level S10 is calculated.

FIG. 5 is a characteristic curve showing a temporal variation of a received signal level value due to fading. Fading is a phenomenon peculiar to mobile communication in which a signal level fluctuates rapidly in a short section. A transmission path between a transmitter and a receiver in mobile communication is a multiple propagation path in which a plurality of radio wave arrival paths exist due to reflection and diffraction of radio waves by surrounding terrain and buildings. In a multiplex propagation path, a plurality of radio waves having different phases interfere with each other, causing a change in signal level and fading. In FIG. 5, the state of fading is worse as the fluctuation width H of the reception level is larger. FIG. 6 is a characteristic curve showing the cumulative probability distribution of the received signal level values in FIG.

Here, the cumulative probability distribution is a distribution obtained by accumulating the probabilities of data that are predetermined reception signal level values with respect to all data of reception signal level values detected at predetermined time intervals at predetermined time intervals, starting from the smaller level value. Is represented.

In FIG. 6, the gradient of the cumulative probability distribution decreases as the variation width H in FIG. 5 increases, and the gradient of the cumulative probability distribution increases as the variation width H decreases. Thus, the slope of the cumulative probability distribution changes according to the fading state, and the fading state can be determined from the slope of the cumulative probability distribution.

Therefore, a cumulative probability distribution for the received signal level values is obtained by statistically processing the plurality of received signal level values S7 in the received level statistical processing section 9, and the cumulative probability distribution is calculated according to the slope of the cumulative probability distribution. The calculated value is calculated as the variable reception signal level S10. For example, the difference between each received signal level value corresponding to 5% and 90% of the cumulative probability distribution is obtained as the variable received signal level S10 corresponding to the slope of the cumulative probability distribution. In this case, the gradient of the cumulative probability distribution (variable reception signal level S10) increases as the difference between the received signal levels decreases, and the gradient (variable reception signal level S10) decreases as the difference between the received signal levels increases.

Then, the fading state is judged by the fading judgment section 10 based on the variable received signal level S10, and the fading judgment value S1 according to the judgment result is obtained.
1 is output to the correction value determination unit 11 as statistical information.

For example, the variable received signal level S10 is divided into several ranks, and the fading state is determined. For example, in the case of being divided into two ranks of 1/0, in FIG. 6, the fading determination value S11 is smaller than the reference slope shown by the dotted line, ie, when the variable reception signal level S10 is large and the fading state is bad. Becomes Further, the fading determination value S11 becomes 0 when the gradient is larger than the reference slope, that is, when the variable reception signal level S10 is small and the fading state is good.

The fading judgment value S11 which is statistical information
Is input to the correction value determination unit 11, the corresponding BTR control width correction value S12 is determined from the BTR control width correction value table based on the fading determination value S11, and the BTR
Output to the unit 5. The BTR control width correction value table is set in advance and stored in the correction value determination unit 11. FIG. 7 shows an example of the BTR control width correction value table according to the present embodiment.

As shown in FIG. 7, the BTR control width correction value S
Reference numeral 12 is set to reduce the control width of the BTR section when the fading state is bad. This is because when the level of a received signal decreases due to fading, the phase obtained from the signal becomes uncertain, and the operation of the demodulation process is more stable if the BTR unit does not correct such phase. If the phase shift changes drastically due to fading, the control of the BTR unit also changes drastically. Even in such a case, it is because the operation of the demodulation process is more stable when the correction by the BTR unit is not performed.

For example, in FIG. 7, when the fading state is good and the fading judgment value S11 is 0, the BT
The R control width correction value S12 becomes 1, and the control width of the BTR unit 5 is not corrected. Further, when the fading state is bad and the fading determination value S11 is 1, the BTR control width correction value S12 is 0.5, and the control unit of the BTR unit 5 is 0.5.
Is corrected. As described above, according to the fading state, which is statistical information of a plurality of received signal level values,
The control width of the BTR unit 5 can be corrected.

In the BTR unit 5, the timing detecting unit 21 detects the symbol clock timing based on the speed at which the phase changes from the phase data S3.
Is output as For example, when n pieces of phase data S3 are input, a point having the least phase change is detected from the n pieces of phase data S3, and the point is output as timing S21.

The timing comparing section 22 determines the timing S21.
Is compared with the previous timing of the symbol clock S6, and shift data S22 having a timing corresponding to the shift is output. When the timing shift data S22 is input to the timing correction unit 23, the direction in which the symbol clock is corrected and the width to be corrected are determined in order to reduce the shift. Further, the control width for the determined symbol clock correction direction and correction width is corrected according to the BTR control width correction value S12, and the corresponding timing correction data S23 is output.

When the timing correction data S23 is input to the clock reproducing unit 24, the timing correction data S23
The symbol clock S6 corrected on the basis of the above is reproduced, and the control width of the BTR unit 5 for correcting and reproducing the symbol clock S6 is corrected in accordance with the fading state which is the statistical information of the plurality of received signal level values. , The symbol clock S6 can be reproduced.

Next, the operation for correcting the local frequency will be described.

As described above, when the reception signal S1 is converted into the IF signal S2 by the frequency conversion unit 1, the phase detection unit 2
A phase is detected from the F signal S2, and one or a plurality of phase data S3 corresponding to the detected phase are output. When the phase data S3 is input to the differential detection unit 3, the phase data S3
3, a phase difference from the previous symbol is detected, and phase difference data S4 corresponding to the phase difference is input to the AFC unit 7.

In the reception level statistical processing section 9,
By statistically processing the plurality of received signal level values S7, a fluctuating received signal level S10 indicating a temporal variation of the received signal level values is calculated. Then, a fading state is determined by the fading determination unit 10 based on the variable received signal level S10, and a fading determination value S11 is determined.
Is output.

Then, similarly to the control for the BTR section 5, the correction value determination section 11 uses the corresponding AFC control width correction value table from the AFC control width correction value table based on the fading determination value S11 which is the statistical information of the received signal level value. Value S1
3 is determined and output to the AFC unit 7. The AFC control width correction value table is also set in advance and stored in the correction value determination unit 11, as in the case of the BTR unit 5. FIG. 7 shows an example of the AFC control width correction value table in the present embodiment.

In the AFC section 7, the phase difference comparing section 31 detects a shift between the input phase difference data S4 and the reference phase difference, and the phase difference shift data S31 corresponding to the shift is detected.
Is output to the control voltage determination unit 32. Here, in the case of a system using π / 4 shift QPSK, the reference phase difference is either ± π / 4 or ± 3π / 4, and this value is stored in the phase difference comparing unit 31 in advance. .

In the control voltage determination section 32, the direction and width for correcting the local frequency are determined based on the phase difference shift data S31, and the control width is corrected according to the AFC control width correction value S13. Then, the corresponding corrected control voltage S8 is output. In this manner, the control width of the AFC unit 7 that is generated by correcting the control voltage S8 according to the fading state, which is statistical information of a plurality of received signal level values, is output, and the control voltage S8 is output. Can be.

Further, the corrected local frequency S9 is generated from the local frequency generator 8 by the output control voltage S8, and the local frequency is changed according to the fading state which is statistical information of a plurality of received signal level values. Can be corrected.

As described above, according to the present embodiment, a fading judgment value is obtained as statistical information from a variable received signal level obtained by statistically processing a plurality of received signal level values. By B
By determining the control widths of the TR unit and the AFC unit, even if the reception level fluctuates greatly due to fading, B
A control error in the TR unit and the AFC unit can be reduced, and a demodulator and a wireless communication device that can improve reception performance can be obtained.

Also, by making the fading judgment value, which is statistical information, a binary value, the BTR unit and A
It is possible to obtain a demodulator and a wireless communication device that can determine the control width of the FC unit, reduce the circuit scale, and perform high-speed processing.

Further, the control width correction values of the BTR section and the AFC section are obtained according to the reception signal level, and the BTR section and the AFC section are corrected.
By correcting the control width of the unit, for example, a specific signal such as a training sequence code is not required, so that the present invention can be applied to any wireless communication system and a highly versatile demodulator and wireless communication device can be obtained. be able to.

Although the case has been described with the present embodiment where the fading determination value is used as statistical information, the statistical information is not limited to this. What is necessary is just to be able to be obtained by statistically processing a plurality of received signal level values detected at a predetermined time, and a variable received signal level representing a temporal variation of the plurality of received signal level values as statistical information. It may be used when determining the correction value of the control width of the BTR unit and the AFC unit. In this case, the fading determination unit is deleted, for example, the variable reception signal level is divided into several ranks, and the control widths of the BTR unit and the AFC unit are determined according to the ranks. Thereby, the same effect as in the present embodiment can be obtained.

Further, a case where a difference between respective received signal level values corresponding to, for example, 5% and 90% of the cumulative probability distribution according to the gradient of the cumulative probability distribution is set as a variable received signal level for determining a fading state. Although described, the variable received signal level is not limited to this. The fluctuating reception signal level may be any as long as it represents the time fluctuation of the reception signal level value. For example, by classifying the received signal level values and counting the number of received signal level values corresponding to the rank, the levels (ranks) corresponding to 5% and 90% can be obtained. From the difference between the level and the level of 5%, a variable received signal level corresponding to the slope of the cumulative probability distribution can be obtained. It is needless to say that the variable received signal level may be used as statistical information.

Further, since the frequency component of the modulated signal itself fluctuates, the accuracy of determining the control width correction value of the BTR unit and the AFC unit decreases, and it is necessary to provide a function of Fourier transform. Although it becomes larger, the state of fading can be determined based on the fluctuation of the frequency component of the received signal level. It is needless to say that the variable received signal level may be used as statistical information.

Further, the fading judgment value, which is statistical information, is set to two values, and the control width correction values of the BTR unit and the AFC unit are set to two values.
Although the case of the type has been described, the present invention is not limited to this. The fading determination value may be divided into three or more ranks. Further, a function for obtaining a control correction value from a value of statistical information such as a fading determination value may be used.
In this case, the circuit scale becomes large, but the control width correction value can be adjusted in detail.

Embodiment 2 Another embodiment according to the present invention will be described with reference to the drawings. FIG. 8 is a block diagram illustrating a configuration of the demodulation unit F of the wireless communication device illustrated in FIG. In FIG. 8, the same or corresponding portions as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. The difference from the above-described embodiment is a reception level statistic processing unit 41 and a correction value determination unit 42.

The reception level statistic processing section 41 stores the reception signal level value S7 for a predetermined time, and statistically processes a plurality of reception signal level values S7 detected at a predetermined time to calculate the reception signal level value S7. In addition to the above-described process of calculating the fluctuation reception signal level S10 indicating a temporal fluctuation, an average of a plurality of reception signal level values S7 detected at a predetermined time is obtained as statistical information and output as an average reception signal level S41. . Further, the correction value determination unit 42 determines a correction value of the control width of the BTR unit 5 and the AFC unit 7 based on the fading determination value S11 and the average received signal level S41 which are the statistical information, and respectively determines the correction value according to the correction value. BTR
The control width correction value S12 and the AFC control width correction value S13 are output.

Next, a description will be given of the operation when correcting and reproducing the symbol clock. As in the above-described embodiment, the cumulative probability distribution for the received signal level value is obtained from the plurality of received signal level values S7 detected by the received level detection unit 6 by statistical processing in the received level statistical processing unit 41. , The variable reception signal level S10 according to the gradient of the cumulative probability distribution is calculated. Further, an average received signal level S41, which is an average of the received signal level values S7, is calculated as statistical information. The variable received signal level S10 is output to the fading determination unit 10, and the average received signal level S41 is
The correction value is output to the correction value determination unit 42.

Then, the fading state is judged by the fading judgment section 10 based on the variable received signal level S10, and the fading judgment value S1 according to the judgment result is obtained.
1 is output to the correction value determination unit 42 as statistical information.

Then, based on the fading determination value S11 as the first statistical information and the average received signal level S41 as the second statistical information, the correction value determining section 42 reads the corresponding BTR control width correction value table from the BTR control width correction value table. Width correction value S
12 is determined and output to the BTR unit 5. The BTR control width correction value table is set in advance and stored in the correction value determination unit 42. FIG. 9 shows an example of a BTR control width correction value table in the present embodiment.

For example, the BTR control width correction value table is as follows.
Fading judgment value S10 and average received signal level S4
It is divided into several ranks depending on the size of 1
The BTR control width correction value is determined based on the rank.

In the BTR control width correction value table shown in FIG. 9, the rank of the average received signal level is divided into two ranks, where 0 is larger than a certain reference value and 1 is smaller. For example, the fading determination value S10
Is 0 and the rank of the average received signal level S41 is 0,
The BTR control width correction value S12 becomes 1, and the control width of the BTR unit 5 is not corrected. Also, the fading determination value S10
Is 1 and the rank of the average received signal level S41 is 1,
The BTR control width correction value S12 becomes 0.2, and the BTR unit 5
Is corrected to a ratio of 0.2. in this way,
The control width of the BTR unit 5 that corrects and reproduces the symbol clock S6 according to the fading state that is the first statistical information of the plurality of received signal level values and the average received signal level that is the second statistical information. Correct the symbol clock S
6 can be played.

Next, the operation for correcting the local frequency will be described. The other operations are the same as those in the above-described embodiment, and the description will not be repeated.

When the local frequency is corrected, the operation is substantially the same as that of the above-described embodiment. However, the reception level statistic processing section 41 statistically processes a plurality of reception signal level values S7 to thereby obtain a variable reception signal. The level S10 and the average received signal level S41 are calculated. The variable reception signal level S10 is output to the fading determination unit 10, and the average reception signal level S41 is output to the correction value determination unit 42.

Then, the fading state is judged by the fading judgment section 10 based on the variable reception signal level S10, and the fading judgment value S1 according to the judgment result is obtained.
1 is output to the correction value determination unit 42 as statistical information. Then, similarly to the control for the BTR unit 5, the correction value determining unit 42 sets the fading determination value S11 as the first statistical information.
And the corresponding A from the AFC control width correction value table based on the average received signal level S41 which is the second statistical information.
The FC control width correction value S13 is determined and output to the AFC unit 7. The AFC control width correction value table also uses BT
As in the case of the R unit 5, it is set in advance and stored in the correction value determination unit 11. FIG. 9 shows an example of the AFC control width correction value table in the present embodiment.

In the AFC section 7, the control width is corrected in accordance with the AFC control width correction value S13, and a corresponding corrected control voltage S8 is output. In this way, the AFC unit that corrects and generates the control voltage S8 according to the fading state that is the first statistical information of the plurality of received signal level values and the average received signal level that is the second statistical information. 7 can be corrected and the control voltage S8 can be output.

Further, the corrected local frequency S9 is generated from the local frequency generator 8 by the output control voltage S8, and the first local signal S9 of the plurality of received signal level values is generated.
The local frequency can be corrected according to the fading state as the statistical information and the average received signal level as the second statistical information.

As described above, according to the present embodiment, in addition to the above-mentioned effects, the first received signal level is obtained from the variable received signal level obtained by statistically processing a plurality of received signal level values.
, A fading determination value is obtained as statistical information, and an average received signal level is obtained as second statistical information. The BT is determined based on the fading state and the average received signal level.
By determining the control width of the R section and the AFC section, BT can be performed even when the reception level fluctuates greatly due to fading.
A control error of the R unit and the AFC unit can be further reduced, and a demodulator and a wireless communication device that can further improve reception performance can be obtained.

Further, by setting the rank of the fading judgment value and the average received signal level, which are statistical information, to binary, the control widths of the BTR section and the AFC section can be determined by bit operation, and the circuit scale can be reduced. Thus, it is possible to obtain a demodulator and a wireless communication device that can perform high-speed processing.

Further, the control width correction value of the BTR and the AFC is obtained according to the received signal level, and the control width of the BTR unit and the AFC unit is corrected, so that a specific signal such as a training sequence code is required. Therefore, the present invention can be applied to any wireless communication system, and a highly versatile demodulator and wireless communication device can be obtained.

Although the case has been described with the present embodiment where the fading determination value and the average received signal level are used as statistical information, the present invention is not limited to this. The statistical information may be variously replaced as in the above-described embodiment. They may be used in combination. Further, since the amount of information is reduced as compared with the present embodiment, usually,
Although the accuracy of determining the control width correction value of the BTR unit and the AFC unit is reduced, only the average received signal level may be used.

Further, the case has been described where the fading judgment value and the average received signal level, which are statistical information, are binary, but the present invention is not limited to this. The fading judgment value and the average received signal level may be divided into three or more ranks. Further, a function for obtaining a control correction value from a value of statistical information such as a fading determination value may be used. In this case, the circuit scale becomes large, but the control width correction value can be adjusted in detail.

Embodiment 3 Still another embodiment according to the present invention will be described with reference to the drawings. FIG. 10 is a block diagram showing a demodulator of the wireless communication device according to one embodiment of the present invention. In FIG. 10, the same or corresponding portions as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. The difference from the above-described embodiment is a correction value determination unit 51.

The correction value deciding section 51 determines the BTR section 5 and the AFC based on the fading judgment value S11 and the average received signal level S41, which are statistical information of a plurality of received signal level values, and the received signal level value S7 at a predetermined time. A correction value of the control width of the unit 7 is determined, and a BTR control width correction value S12 and an AFC control width correction value S13 corresponding to the correction values are output.

The operation of the correction determining section 51 when determining the correction value of the control width of the BTR section 5 will be described.

The correction value determining section 51 determines the fading determination value S which is the first statistical information of the plurality of received signal level values.
11 and the average received signal level S4 as the second statistical information
1, based on the received signal level value S7 at a predetermined time, a corresponding BTR control width correction value S12 is determined from the BTR control width correction value table, and is output to the BTR unit 5. The BTR control width correction value table is set in advance and stored in the correction value determination unit 51. FIG. 11 shows an example of a BTR control width correction value table according to the present embodiment.

For example, the BTR control width correction value table is
Fading judgment value S10, average received signal level S41
And the received signal level value S7 at the current time is divided into several ranks, and the BTR control width correction value is determined according to the rank.

In the BTR control width correction value table shown in FIG. 11, the rank of the average received signal level S41 is divided into two ranks, where 0 is larger than a certain reference value and 1 is smaller. Further, the rank of the received signal level value S7 at the present time is also divided into two ranks.
0 is larger than a certain reference value, and 1 is smaller.

For example, if the fading judgment value S10 is 0,
When the rank of the average received signal level S41 is 0 and the rank of the current received signal level value S7 is 0, the BTR control width correction value S12 is 1, and the control width of the BTR unit 5 is not corrected. When the fading determination value S10 is 1, the rank of the average received signal level S41 is 1, and the rank of the current received signal level S7 is 1, the BTR control width correction value S1
2 becomes 0. That is, the control width of the BTR unit 5 becomes 0, and the control of the BTR unit is not performed. As described above, according to the fading state as the first statistical information of the plurality of received signal level values, the average received signal level as the second statistical information, and the current received signal level value, the BTR
A correction value for the control width of the unit 5 is determined, and the symbol clock S6 can be reproduced by correcting the control width of the BTR unit 5 for correcting and reproducing the symbol clock S6.

Next, the operation of the correction determining section 51 for determining a correction value for the control width of the AFC section 7 will be described. The other operations are the same as those in the above-described embodiment, and the description is omitted.

When the correction value for the control width of the AFC unit 7 is determined, the operation is substantially the same as that of the above-described embodiment.
Similarly to the control for the TR unit 5, the correction value determination unit 51 includes a fading determination value S11 which is first statistical information of a plurality of received signal level values, an average received signal level S41 which is second statistical information, and further, The corresponding AFC control width correction value S13 is determined from the AFC control width correction value table based on the current reception signal level value S7, and the AFC
Output to the unit 7. The AFC control width correction value table is also set in advance and stored in the correction value determination unit 11, as in the case of the BTR unit 5. FIG. 11 shows an example of the AFC control width correction value table in the present embodiment.

As described above, the AFC unit according to the fading state as the first statistical information of the plurality of received signal level values, the average received signal level as the second statistical information, and the current received signal level value. The correction value for the control width of 7 is determined, and the AFC generated by correcting the control voltage S8
The control width of the unit 7 can be corrected, and the control voltage S8 can be output.

Further, the corrected local frequency S9 is generated from the local frequency generator 8 by the output control voltage S8, and the fading state and the average received signal level, which are statistical information of the received signal level value, and the current The local frequency can be corrected according to the received signal level value.

As described above, according to the present embodiment, in addition to the above-described effects, the first received signal level is obtained from the variable received signal level obtained by statistically processing a plurality of received signal level values.
A fading judgment value is obtained as statistical information of the FTR, and an average received signal level is obtained as the second statistical information. By making the determination, even when the reception level fluctuates greatly due to fading, the control error of the BTR unit and the AFC unit can be further reduced, and a demodulator and a wireless communication device that can further improve the reception performance can be obtained.

Further, by making the fading judgment value, the average received signal level rank, and the current received signal level value rank binary, the control width of the BTR section and the AFC section can be determined by bit operation. Thus, it is possible to obtain a demodulator and a wireless communication device capable of reducing the circuit scale and performing high-speed processing.

Further, the control width correction values of the BTR and the AFC are obtained in accordance with the received signal level, and the control widths of the BTR unit and the AFC unit are corrected, so that a specific signal such as a training sequence code is required. Therefore, the present invention can be applied to any wireless communication system, and a highly versatile demodulator and wireless communication device can be obtained.

Although the case has been described with the present embodiment where the fading determination value and the average received signal level are used as statistical information, the present invention is not limited to this. The statistical information may be variously replaced as in the above-described embodiment. They may be used in combination.

Further, the case has been described where the fading judgment value and the average received signal level, which are statistical information, and the received signal level value at the present time are binary, but the present invention is not limited to this. The fading determination value, the average received signal level, and the current received signal level value may be divided into three or more ranks. Further, a function for obtaining a control correction value from a value of statistical information such as a fading determination value may be used. In this case, the circuit scale becomes large, but the control width correction value can be adjusted in detail.

[0133]

As described above, according to the present invention, one or a plurality of statistical information is obtained by statistically processing a plurality of received signal level values detected at a predetermined time. By determining the control width correction value for correcting the processing of the demodulation processing unit according to the statistical information, the control error of the demodulation processing unit can be reduced even when the reception level fluctuates greatly, and the reception performance can be improved. In addition, the present invention can be applied to any wireless communication system, and a highly versatile demodulator can be obtained.

Further, according to the next invention, a fluctuation reception signal level representing a temporal fluctuation of a plurality of reception signal level values detected at a predetermined time is obtained as statistical information, and one or more fluctuation reception signal levels including the fluctuation reception signal level are obtained. By determining the control width correction value for correcting the processing of the demodulation processing means according to the plurality of pieces of statistical information, the control error of the demodulation processing means can be reduced even when the reception level fluctuates greatly, and the reception performance is improved. It is possible to obtain a highly versatile demodulator that can be applied to any wireless communication system while being improved.

Further, according to the next invention, a fading state is obtained from a variable received signal level representing a temporal variation of a plurality of received signal level values detected at a predetermined time as statistical information, and the fading state is determined. By determining the control width correction value for correcting the processing of the demodulation processing means according to one or more statistical information including, even if the reception level fluctuates greatly, the control error of the demodulation processing means can be reduced, It is possible to improve the receiving performance, apply the present invention to any wireless communication system, and obtain a highly versatile demodulator.

Further, according to the next invention, an average received signal level representing an average of a plurality of received signal level values detected at a predetermined time is obtained as statistical information, and one or more average received signal levels including the average received signal level are obtained. By determining a control width correction value for correcting the processing of the demodulation processing means according to the statistical information,
Even when the reception level fluctuates greatly, the control error of the demodulation processing means can be reduced, the reception performance can be improved, and a versatile demodulator that can be applied to any wireless communication system can be obtained. it can.

Further, according to the next invention, when determining the control width correction value for correcting the processing of the demodulation processing means according to one or a plurality of statistical information, the received signal level value at a predetermined time is used. , Even if the reception level fluctuates greatly,
Further, the control error of the demodulation processing means can be reduced, the reception performance can be improved, and a demodulator which can be applied to any wireless communication system and has high versatility can be obtained.

Further, according to the next invention, the demodulation processing means includes a symbol clock timing regenerating means for correcting in accordance with the phase of the received signal to regenerate a symbol clock, and the correction determining means includes a symbol clock timing regenerating means. By determining the control width correction value for correcting the control of the means, the control error of the symbol clock timing reproducing means can be reduced even when the reception level fluctuates greatly, and the reception performance can be improved. The present invention can be applied to any wireless communication system and can provide a highly versatile demodulator.

Further, according to the next invention, the demodulation processing means includes frequency control means for controlling generation of a local frequency according to the phase of the received signal, and the correction determining means corrects the control of the frequency control means. By determining the control width correction value, it is possible to reduce the control error of the frequency control means even when the reception level fluctuates drastically, to improve the reception performance, and to apply to any wireless communication system. An applicable and highly versatile demodulator can be obtained.

Further, according to the next invention, the demodulator statistically processes a plurality of received signal level values detected at a predetermined time to obtain one or a plurality of statistical information.
Alternatively, by determining a control width correction value for correcting the processing of the demodulation processing means according to a plurality of pieces of statistical information, the control error of the demodulation processing means can be reduced even when the reception level fluctuates greatly, and the reception performance can be reduced. And can be applied to any wireless communication system, and a highly versatile wireless communication device can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a wireless communication device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a demodulator according to Embodiment 1 of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a BTR unit according to the present invention.

FIG. 4 is a block diagram illustrating a configuration of an AFC unit according to the present invention.

FIG. 5 is a characteristic curve showing a temporal variation of a received signal level value.

FIG. 6 is a characteristic curve showing a cumulative probability distribution of a received signal level value.

FIG. 7 is a diagram illustrating a BTR unit and an A according to the first embodiment of the present invention.
9 is a control width correction value table of the FC unit.

FIG. 8 is a block diagram showing a configuration of a demodulator according to Embodiment 2 of the present invention.

FIG. 9 shows a BTR unit and an A according to a second embodiment of the present invention.
9 is a control width correction value table of the FC unit.

FIG. 10 is a block diagram showing a configuration of a demodulator according to Embodiment 3 of the present invention.

FIG. 11 is a control width correction value table for a BTR unit and an AFC unit according to Embodiment 3 of the present invention.

FIG. 12 is a block diagram illustrating a configuration of a conventional demodulator.

FIG. 13 is a block diagram showing a configuration of a conventional BTR unit.

FIG. 14 is a block diagram illustrating a configuration of a conventional AFC unit.

FIG. 15 is a block diagram showing a configuration of a conventional frequency automatic control circuit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 frequency conversion unit 2 phase detection unit 3 delay detection unit 4 reception data generation unit 5 BTR unit 6 reception level detection unit 7 AFC unit 8 local frequency generation unit 9, 41 reception level statistical processing unit 10 fading determination unit 11, 42, 51 Correction value determination unit 21 Timing detection unit 22 Timing comparison unit 23 Timing correction unit 24 Clock recovery unit 31 Phase difference comparison unit 32 Control voltage determination unit 101 Quadrature demodulation unit 102 Cross-correlation coefficient calculation circuit 103 Quality calculation circuit 104 Signal quality determination circuit 105 AFC data generation circuit 106 PLL circuit 107 Voltage controlled oscillation circuit A interface unit B control unit C modulation unit D RF unit E antenna F demodulation unit

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Takayoshi Semasa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (8)

[Claims] 1. A demodulation processing means for demodulating a received signal using a local frequency, outputting received data and a symbol clock, detecting a power level of the received signal and receiving a signal level value corresponding to the level. Receiving level statistical means for statistically processing a plurality of the received signal level values detected in a predetermined time to obtain one or a plurality of types of statistical information; A demodulator comprising: a correction determining means for determining a control width correction value for correcting the processing of the demodulation processing means according to the type of statistical information. 2. The demodulator according to claim 1, wherein the statistical information is a variable received signal level representing a temporal change of the plurality of received signal level values. 3. The demodulator according to claim 1, wherein the statistical information is a fading state obtained from a variable received signal level representing a temporal change of the plurality of received signal level values. 4. The demodulator according to claim 1, wherein the statistical information is an average received signal level representing an average of the plurality of received signal level values. 5. The apparatus according to claim 1, wherein said correction determining means uses a received signal level value at a predetermined time when determining a control width correction value for correcting the processing of said demodulation processing means. 5. The demodulator according to any one of 4. 6. The demodulation processing means includes a symbol clock timing regenerating means for correcting a symbol clock in accordance with a phase of the received signal to regenerate a symbol clock. The correction determining means controls the symbol clock timing regenerating means. The demodulator according to any one of claims 1 to 5, wherein a control width correction value for correcting (i) is determined. 7. The demodulation processing means includes frequency control means for controlling generation of a local frequency in accordance with the phase of the received signal, and the correction determining means corrects control by the frequency control means. The demodulator according to claim 1, wherein the value is determined. 8. A radio communication apparatus for performing radio communication by modulating / demodulating between a plurality of demodulators, wherein a demodulator demodulates a received signal using a local frequency and outputs received data and a symbol clock. Receiving level detecting means for detecting a power level of the received signal and outputting a received signal level value corresponding to the level; and statistically processing a plurality of the received signal level values detected at a predetermined time. Receiving level statistical processing means for obtaining one or more kinds of statistical information, and correction determining means for determining a control width correction value for correcting the processing of the demodulation processing means according to the one or more kinds of statistical information. A wireless communication device characterized by the above-mentioned.