JPH10164163A - Data receiving device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Unnecessary D from baseband signal after quadrature detection
Provided is a data receiving device capable of performing highly accurate demodulation processing by having a function of detecting a C offset component and removing it. SOLUTION: A received RF signal is converted into baseband I and Q signals using a quadrature detector 2 and LPFs 8 and 9 for removing harmonic components. These signals are A / D converted, reception band is limited through reception filters 11 and 12, and based on the discrimination point information obtained by the symbol discrimination point detection section 13, sampling sections 14 and 15 perform reception filtering at symbol discrimination points. Only outputs In and Qn are detected. On the other hand, the DC offset detection unit 16 calculates the difference value of each of the above In and Qn and the difference value of the squared envelope Rn obtained from In and Qn, and uses these values to calculate In and Qn. Unnecessary DC offset components dei = di and deq = dq included are detected. Then, the subtractors 17 and 18 subtract dei and deq from In and Qn to remove unnecessary DC offset components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data receiving apparatus used in digital radio communication, and more particularly to a data receiving apparatus which detects unnecessary DC offset components contained in In and Qn and removes the components, so that a baseband demodulation processing unit can be used. The present invention relates to a data receiving apparatus capable of performing highly accurate demodulation processing without causing distortion.

[0002]

2. Description of the Related Art Conventionally, a data receiving apparatus used in digital radio communication is described in, for example, "Modulation and Demodulation of Digital Radio Communication" by Yoichi Saito, IEICE, 1996, pp. 114-1
The one described in No. 19 is known.

FIG. 10 is a block diagram showing a configuration of a conventional data receiving apparatus. The data receiving apparatus shown in FIG. 10 includes a reception signal input terminal 1 for receiving a reception RF signal or a frequency-converted reception IF signal, multipliers 3 and 4, a π / 2 phase shifter 5, and an input reception signal. A local oscillator 6 for generating a carrier signal equal to the center frequency;
Low-pass filters 7 and 8 for removing a double carrier component contained in the quadrature output, A / D converters 9 and 10 for converting the outputs of the low-pass filters 7 and 8 into digital signals, and an A / D Receiving filters 11 and 12 for limiting the output of the converters 9 and 10 in a receiving band, a symbol discriminating point detecting unit 13 for detecting a symbol discriminating point from the output of the receiving filters 11 and 12, and a symbol discriminating point detecting unit Sampling units 14 and 15 that detect only the reception filter output at the symbol identification point based on the identification point information determined in 13, the sampling unit 14,
Baseband demodulator for demodulating 15 output signals
19, a decoded data output terminal 20 for detecting decoded data output from the received RF signal baseband demodulation processing unit 19
It is composed of Then, the multipliers 3 and 4 and π /
The two-phase shifter 5 and the local oscillator 6 constitute a quadrature detector 2 for frequency-converting an input received signal and detecting an in-phase component I and a quadrature component Q of a baseband.

Next, the operation of the conventional example will be described with reference to FIG. Now, it is assumed that the received signal S (t) applied to the received signal input terminal 1 in FIG. 10 is represented by the following equation.

S (t) = I0 (t) cos (2πfct) + Q0 (t) sin (2πfct) (1) I0 (t): In-phase component of baseband Q0 (t): Quadrature component of baseband fc: Receiving RF frequency or IF frequency The above-mentioned received signal S (t) is frequency-converted into a baseband through the quadrature detection unit 2, and a double carrier component is removed by low-pass filters 7 and 8. (t), the orthogonal component Q0 (t) is detected. The I / O (t) and Q0 (t) are sampled by the A / D converters 9 and 10 so that the sample value sequences I0 (kTs) and Q0 (kT
s) (Ts: sampling period of A / D converters 9 and 10).

Next, I0 (kTs) and Q0 (kTs) are subjected to reception band limitation by reception filters 11 and 12 having root Nyquist characteristics and the like, and baseband signals I (kTs) and Q (kTs) are obtained. The symbol discrimination point detection unit 13 detects symbol discrimination point information from I (kTs) and Q (kTs), and the sampling units 14 and 15 output the reception filter output In at the symbol discrimination point based on this information.
Only Qn is detected and output. And this In, Qn
Is input to the baseband demodulation processing unit 19 and demodulated according to a predetermined demodulation method.

Here, as one example, π / 4 shift QPSK
The case where a modulation signal is demodulated by differential detection is shown.

Now, it is assumed that In and Qn are represented by the following equations.

In = A · cos (φn) (2) Qn = A · sin (φn) (3) φn: Modulation phase In the case of differential detection, the baseband demodulation processing unit 19 uses the above I
The following arithmetic processing is performed on n and Qn.

[0010] Xn = InIn-1 + QnQn- 1 = A 2 · cos (Δφn) ··· (4) Yn = QnIn-1 - InQn-1 = A 2 · sin (Δφn) ··· (5) Δφn = Φn−φn−1: modulation phase difference Then, a code determination is performed on the Xn and Yn to obtain final decoded data.

As described above, in the conventional data receiving apparatus as well, the received RF signal or the IF
The signal is frequency-converted to baseband, and baseband demodulation is performed using the signal value at the detected symbol discrimination point, whereby highly accurate demodulation processing can be realized.

[0012]

However, in the conventional data receiving apparatus, when unnecessary DC offset components are superimposed on the multipliers 3 and 4 in the quadrature detector 2 and the low-pass filters 7 and 8, the baseband demodulation processing is performed. Department
In 19, there is a problem that distortion occurs and the error rate characteristic is deteriorated. For example, when unnecessary DC offsets di and dq are superimposed on the outputs of the low-pass filters 7 and 8, In and Qn in the above equations (2) and (3) are as follows.

In = A · cos (φn) + di (6) Qn = A · sin (φn) + dq (7) As an example, the above-mentioned In and Qn were subjected to delay detection. In such a case, the following result is obtained.

[0014] Xn = InIn-1 + QnQn- 1 = A 2 · cos (Δφn) + diA (cos (φn) + cos (φn-1)) + dqA (sin (φn) + sin (φn-1)) + di 2 + dq ^{2 ··· (8) Yn = QnIn} -1 - InQn-1 = A 2 · sin (Δφn) + diA (sin (φn) -sin (φn-1)) -dqA (cos (φn) -cos (φn- 1)) (9) The second and subsequent items on the right side of the above equations (8) and (9) are distortion components caused by DC offsets di and dq, which degrade the error rate characteristics.

The present invention solves such a conventional problem. The present invention solves the above-mentioned problem by providing a difference between the baseband signal values In and Qn at the symbol identification point and a squared envelope obtained from In and Qn. Unnecessary DC offset components included in In and Qn are detected by calculating a difference value of the line Rn and providing a DC offset detector for detecting DC offset components dei = di and deq = dq using these values. It is an object of the present invention to provide a data receiving apparatus capable of performing high-precision demodulation processing without causing distortion in a baseband demodulation processing unit by removing this.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a reception signal input terminal for receiving a reception RF signal or a frequency-converted reception IF signal, and a base station for converting the frequency of the reception signal. A quadrature detector comprising a local oscillator for detecting in-phase component I and quadrature component Q of a band, first and second multipliers, and a π / 2 phase shifter; and in-phase and quadrature outputs of the quadrature detector , A first and a second low-pass filter for removing a double carrier component included in the first and second A / A filters for converting outputs of the first and second low-pass filters into digital signals. A D converter, first and second receiving filters for limiting a receiving band of output signals of the first and second A / D converters, and the first and second receiving filters;
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculation unit for obtaining a difference value Di between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; The difference value Dq between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit.
A second difference operation unit for obtaining the value of the first and second sampling units, and a square envelope operation unit for obtaining the value of the square envelope at the symbol identification point using the outputs of the first and second sampling units. A third difference calculation unit for obtaining a difference value Dr between the current value of the square envelope and the value of the square envelope one symbol before using the output of the square envelope calculation unit; Using the outputs Di, Dq, and Dr of the first, second, and third difference calculation units, d = Dr / (2
(Di + Dq)), and includes a DC offset estimating calculation unit that outputs DC offset estimated values dei and deq as dei = deq = d.

According to the present invention, even when unnecessary DC offset components having the same value are superimposed on the first and second multipliers in the quadrature detection unit and the first and second low-pass filters, the DC power is reduced. By detecting and removing this in the offset detection section, it is possible to perform high-precision demodulation processing without causing distortion in the baseband demodulation processing section.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides a reception signal input terminal for inputting a reception RF signal or a frequency-converted reception IF signal; A quadrature detector comprising a local oscillator for detecting an in-phase component I and a quadrature component Q, first and second multipliers, and a π / 2 phase shifter; and an in-phase and quadrature output of the quadrature detector First and second low-pass filters for removing twice as many carrier components,
First and second A / D converters for converting the output of the low-pass filter into digital signals, and first and second A / D converters for limiting the reception signals of the first and second A / D converters. A second receiving filter, a symbol discriminating point detecting section for detecting a symbol discriminating point from an output of the first and second receiving filters, and a discriminating point information obtained by the symbol discriminating point detecting section. First and second sampling units for detecting only a reception filter output at a symbol identification point;
As will be described later, a DC offset detecting section for detecting an unnecessary DC offset component contained therein using outputs of the first and second sampling sections, and an unnecessary DC offset detected by the DC offset detecting section. Components dei, deq
From the outputs of the first and second sampling units, and a baseband demodulation processing unit for demodulating the outputs of the first and second subtraction units. A decoded data output terminal for detecting decoded data output from the baseband demodulation processing section, and the DC offset detection section uses the output of the first sampling section to output a current baseband signal. A first difference calculation unit for obtaining a difference value Di between the in-phase component and the in-phase component of the baseband signal one symbol before, and a current baseband signal quadrature component using an output of the second sampling unit. A second difference operation unit for obtaining a difference value Dq between orthogonal components of the baseband signal one symbol before, and a square envelope at a symbol identification point using outputs of the first and second sampling units Squared envelope for finding the value of a line And parts, the value of the square envelope of current using an output of said square envelope calculation unit and the preceding symbol 2
D = Dr / using a third difference calculation unit for obtaining a difference value Dr between the values of the power envelope and the outputs Di, Dq, Dr of the first, second, and third difference calculation units. (2 (Di + Dq)), and includes a DC offset estimating operation unit that outputs DC offset estimation values dei and deq as dei = deq = d, and a first and a second in the quadrature detection unit. Even when an unnecessary DC offset component having the same value is superimposed on the multiplier or the first and second low-pass filters,
By detecting and removing this in the DC offset detection section, there is an effect that the baseband demodulation processing section can perform highly accurate demodulation processing without causing distortion.

According to the second aspect of the present invention, the reception R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a first difference calculator for calculating a difference value Di between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit. A second difference operation unit for obtaining a difference value Dq, and a second difference operation unit for obtaining a value of a square envelope at a symbol identification point using outputs of the first and second sampling units.
A third section for obtaining a difference value Dr between the current value of the square envelope and the value of the square envelope one symbol before using the output of the square envelope operation section and the output of the square envelope operation section. And the outputs Di, D of the first, second, and third difference calculation units.
A DC offset estimating operation unit for calculating and outputting d = Dr / (2 (Di + Dq)) using q and Dr, and a moving average value de of d for smoothing the output d of the DC offset estimating operation unit A moving average calculation unit for calculating and outputting DC offset estimated values dei and deq as dei = deq = de, and a first and second multiplier in the quadrature detection unit, Even when unnecessary DC offset components having the same value are superimposed in the second low-pass filter,
By detecting and removing this in the DC offset detection section, there is an effect that the baseband demodulation processing section can perform highly accurate demodulation processing without causing distortion.

According to the third aspect of the present invention, the reception R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a difference between the current baseband signal orthogonal component and the immediately preceding baseband signal orthogonal component using the output of the second sampling unit. A second difference operation unit for obtaining a value, a square envelope operation unit for obtaining a value of a square envelope at a symbol identification point using outputs of the first and second sampling units, and , The output of the squared envelope calculation unit A third difference calculator for calculating a difference value between the current value of the squared envelope and the value of the squared envelope one symbol before, and the first, second, and third difference calculators Moving average value Dei of the output of
D = Der / using the first, second, and third moving average calculators for obtaining Deq and Der and the outputs Dei, Deq, and Der of the first, second, and third moving average calculators. (2 (Dei +
Deq)), and includes a DC offset estimating operation unit that outputs DC offset estimation values dei, deq as dei = deq = d, and a first and a second multiplier in the quadrature detection unit. Even when unnecessary DC offset components having the same value are superimposed in the first and second low-pass filters, the DC offset detection unit detects and removes the unnecessary DC offset components, thereby causing distortion in the baseband demodulation processing unit. It is possible to perform a highly accurate demodulation process.

According to the fourth aspect of the present invention, the reception R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a difference between the current baseband signal orthogonal component and the immediately preceding baseband signal orthogonal component using the output of the second sampling unit. A second difference operation unit for obtaining a value, a square envelope operation unit for obtaining a value of a square envelope at a symbol identification point using outputs of the first and second sampling units, and , The output of the squared envelope calculation unit A third difference calculator for calculating a difference value between the current value of the squared envelope and the value of the squared envelope one symbol before, and the first, second, and third difference calculators Moving average value Dei of the output of
D = Der / using the first, second, and third moving average calculators for obtaining Deq and Der and the outputs Dei, Deq, and Der of the first, second, and third moving average calculators. (2 (Dei +
Deq)) is calculated and output, and a moving average value de of d is calculated to smooth the output d of the DC offset estimating calculation unit, and dei = deq = de
And a fourth moving average calculating section for outputting estimated DC offset values dei and deq as the first and second multipliers in the quadrature detection section, and the first and second low-pass filters. Even when unnecessary DC offset components having the same value are superimposed on each other, the DC offset detection unit detects and removes the unnecessary DC offset components, so that the baseband demodulation processing unit can perform highly accurate demodulation processing without causing distortion. Has the effect of being able to.

According to a fifth aspect of the present invention, the reception R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a second difference calculator for calculating a difference value Di2 between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before. And a third difference operation for obtaining a difference value Dq1 between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit. And a fourth difference calculating unit for calculating a difference value Dq2 between the baseband signal orthogonal component one symbol before and the baseband signal orthogonal component two symbols before, and the first and second sampling units A square envelope calculating unit for calculating the value of the square envelope at the symbol identification point using the output of the unit, and the value of the current square envelope using the output of the square envelope calculating unit. A fifth difference calculating unit for obtaining a difference value Dr1 between the value of the square envelope of one symbol before, and the value of the square envelope of one symbol before and the value of the square envelope of two symbols before The difference value D between
a sixth difference calculation unit for determining r2, and outputs Di1, of the first, second, third, fourth, fifth, and sixth difference calculation units,
Di1 is written in one row using Di2, Dq1, Dq2, Dr1, and Dr2.
The inverse matrix C ^-1 of the matrix C having columns, Dq1 as 1 row and 2 columns, Di2 as 2 rows and 1 column, and Dq2 as 2 rows and 2 columns is obtained.
i, deq) ^T = C ^-1 (Dr1, Dr2) ^T is calculated and dei, deq
Is output as an estimated value of the DC offset, and a first and second multipliers in the quadrature detection unit and different values of the first and second low-pass filters are provided. Even when an unnecessary DC offset component is superimposed, by detecting and removing the DC offset component in the DC offset detection unit, the baseband demodulation processing unit can perform high-precision demodulation processing without causing distortion. Have.

According to a sixth aspect of the present invention, a receiving R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a second difference calculator for calculating a difference value Di2 between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before. And a third difference operation for obtaining a difference value Dq1 between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit. And a fourth difference calculating unit for calculating a difference value Dq2 between the baseband signal orthogonal component one symbol before and the baseband signal orthogonal component two symbols before, and the first and second sampling units A square envelope calculating unit for calculating the value of the square envelope at the symbol identification point using the output of the unit, and the value of the current square envelope using the output of the square envelope calculating unit. A fifth difference calculating unit for obtaining a difference value Dr1 between the value of the square envelope of one symbol before, and the value of the square envelope of one symbol before and the value of the square envelope of two symbols before The difference value D between
a sixth difference calculation unit for determining r2, and outputs Di1, of the first, second, third, fourth, fifth, and sixth difference calculation units,
Di1 is written in one row using Di2, Dq1, Dq2, Dr1, and Dr2.
The inverse matrix C ^-1 of the matrix C having columns, Dq1 as 1 row and 2 columns, Di2 as 2 rows and 1 column, and Dq2 as 2 rows and 2 columns is obtained.
x, dy) ^T = C ^-1 (Dr1, Dr2) DC offset estimating operation unit for calculating and outputting ^T, and a moving average of dx, dy for smoothing the output dx, dy of the DC offset estimating operation unit It includes first and second moving average calculators for calculating values dei and deq and outputting the calculated values as DC offset estimation values. The first and second multipliers in the quadrature detector, Even when unnecessary DC offset components of different values are superimposed on the first and second low-pass filters,
By detecting and removing this in the DC offset detection section, the baseband demodulation processing section can perform high-precision demodulation processing without causing distortion.

According to a seventh aspect of the present invention, the reception R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a second difference for calculating a difference between an in-phase component of the baseband signal one symbol before and an in-phase component of the baseband signal two symbols before. An operation unit, a third difference operation unit for obtaining a difference value between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit, and Yo , Fourth for calculating a difference value between the baseband signal quadrature components of one symbol before and two symbols preceding the baseband signal quadrature component
, A square envelope operation unit for calculating the value of the square envelope at the symbol identification point using the output of the first and second sampling units, and the square envelope operation A fifth difference calculating unit for calculating a difference value between the current value of the squared envelope and the value of the squared envelope one symbol before using the output of the unit;
A sixth difference calculation unit for calculating a difference value between a value of a square envelope before one symbol and a value of a square envelope before two symbols, and the first, second, third, and Fourth, fifth, sixth
Moving average values Dei1, Dei2, Deq
A first, a second, a third, a fourth, a fifth, and a sixth moving average calculator for determining 1, Deq2, Der1, and Der2;
Using the outputs Dei1, Dei2, Deq1, Deq2, Der1, Der2 of the second, third, fourth, fifth, and sixth moving average calculators,
Dei1 in one row and one column, Deq1 in one row and two columns, and Dei2 in two rows and one
The inverse matrix C ⁻¹ of the matrix C having two columns and Deq 2 as two rows and two columns is obtained, and (dei, deq) ^T = C ⁻¹ (Dr1, Dr2) ^T is calculated. A DC offset estimator for outputting an estimated value,
Even when unnecessary DC offset components having different values are superimposed in the first and second multipliers in the quadrature detection unit and the first and second low-pass filters, the DC offset detection unit detects this. The removal has the effect that the baseband demodulation processing section can perform high-precision demodulation processing without causing distortion.

The invention according to claim 8 of the present invention provides a receiving R
A reception signal input terminal for inputting an F signal or a frequency-converted reception IF signal; a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband; And a quadrature detector comprising a π / 2 phase shifter, and a first and a second filter for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector.
A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second reception filters for limiting a reception band of an output signal of a filter, a symbol identification point detection unit for detecting a symbol identification point from an output of the first and second reception filters, and the symbol First and second sampling units for detecting only the reception filter output at the symbol identification point based on the identification point information obtained by the identification point detection unit; and the first and second sampling units as described later. A DC offset detecting unit for detecting unnecessary DC offset components contained therein using the output of the DC offset detecting unit, and unnecessary DC offset components dei and deq detected by the DC offset detecting unit are sampled by the first and second sampling units. Department First and second subtraction sections for subtracting from the power, a baseband demodulation processing section for demodulating outputs of the first and second subtraction sections, and decoding as an output of the baseband demodulation processing section. A decoding data output terminal for detecting data; wherein the DC offset detection unit uses the output of the first sampling unit to output a current baseband signal in-phase component and a baseband signal in-phase component one symbol before. And a second difference for calculating a difference between an in-phase component of the baseband signal one symbol before and an in-phase component of the baseband signal two symbols before. An operation unit, a third difference operation unit for obtaining a difference value between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit, and Yo , Fourth for calculating a difference value between the baseband signal quadrature components of one symbol before and two symbols preceding the baseband signal quadrature component
, A square envelope operation unit for calculating the value of the square envelope at the symbol identification point using the output of the first and second sampling units, and the square envelope operation A fifth difference calculating unit for calculating a difference value between the current value of the squared envelope and the value of the squared envelope one symbol before using the output of the unit;
A sixth difference calculation unit for calculating a difference value between a value of a square envelope before one symbol and a value of a square envelope before two symbols, and the first, second, third, and Fourth, fifth, sixth
Moving average values Dei1, Dei2, Deq
A first, a second, a third, a fourth, a fifth, and a sixth moving average calculator for determining 1, Deq2, Der1, and Der2;
Using the outputs Dei1, Dei2, Deq1, Deq2, Der1, Der2 of the second, third, fourth, fifth, and sixth moving average calculators,
Dei1 in one row and one column, Deq1 in one row and two columns, and Dei2 in two rows and one
A DC offset estimator for calculating an inverse matrix C ^-1 of a matrix C having two columns and Deq2 as two rows and two columns, further calculating (dx, dy) ^T = C ^-1 (Dr1, Dr2) ^T , and A seventh and an eighth moving average calculation for calculating moving averages dei, deq of dx, dy for smoothing the outputs dx, dy of the DC offset estimating calculation unit and outputting the calculated moving averages as estimated DC offset values. The first and second multipliers in the quadrature detection unit, and the first and second low-pass filters, even when unnecessary DC offset components having different values are superimposed, By detecting and removing this in the offset detecting section, the baseband demodulating processing section has an effect that a highly accurate demodulation processing without distortion can be performed.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(First Embodiment) FIGS. 1 and 2 are block diagrams showing a configuration of a data receiving apparatus according to a first embodiment. The data receiving device of FIG.
A reception signal input terminal 1 for inputting a frequency-converted reception IF signal; multipliers 3 and 4; a π / 2 phase shifter 5; and a local oscillator 6 for generating a carrier signal equal to the center frequency of the input reception signal. , Low-pass filters 7 and 8 for removing double carrier components contained in the in-phase and quadrature outputs of the quadrature detector 2, and an A / D converter for converting the outputs of the low-pass filters 7 and 8 into digital signals 9, 10; reception filters 11 and 12 for limiting the output band of the A / D converters 9 and 10 in a reception band; and a symbol discrimination point detection unit for detecting a symbol discrimination point from the output of the reception filters 11 and 12. 13, sampling units 14 and 15 for detecting only the reception filter output at the symbol discrimination point based on the discrimination point information obtained by the symbol discrimination point detection unit 13, and outputs In and Qn of the sampling units 14 and 15 Use unnecessary contained therein A DC offset detector 16 for detecting a DC offset component, and a DC offset detector
The unwanted DC offset component dei detected at 16,
subtracting units 17 and 18 for subtracting deq from the outputs In and Qn of the sampling units 14 and 15; a baseband demodulating unit 19 for demodulating the output signals of the subtracting units 17 and 18; It comprises a decoded data output terminal 20 for detecting decoded data output from the band demodulation processing unit 19.
The multipliers 3 and 4, the π / 2 phase shifter 5, and the local oscillator 6 convert the frequency of the input received signal and detect the in-phase component I and the quadrature component Q of the baseband. Constituting No. 2.

FIG. 2 is a block diagram showing the configuration of the DC offset detecting section 16.
Is composed of a delay unit 22 and a subtractor 23 for one symbol, and obtains a difference value Din between the in-phase component of the current baseband signal and the in-phase component of the baseband signal one symbol before using the output In of the sampling unit 14. Calculation section 21, a one-symbol delay unit 25 and a subtractor 26, and the output Qn of the sampling unit 15
And a difference calculation unit 24 for calculating a difference value Dqn between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before, and the output I of the sampling units 14 and 15.
n, Qn, the value of the squared envelope Rn at the symbol identification point
, A delay unit 29 between one symbol and a subtractor 30, and the output Rn of the square envelope operation unit 27 and the current value of the square envelope and one symbol A difference calculation unit 28 for obtaining a difference value Drn between the values of the previous squared envelope, and outputs Din, Dqn, D of the difference calculation units 21, 24, 28
and a DC offset estimating operation unit 31 for calculating DC offset estimated values dei and deq using rn.

The operation of the data receiving apparatus of the first embodiment configured as described above will be described with reference to FIGS.

Now, the reception signal S (t) applied to the reception signal input terminal 1 in FIG.
Shall be represented by

The above-mentioned received signal S (t) is frequency-converted to a baseband through the quadrature detection unit 2, and a double carrier component is removed by low-pass filters 7 and 8, and the baseband in-phase component I 0 (t) + Di and the quadrature component Q0 (t) + dq are detected. Here, di and dq are unnecessary DC offset components superimposed on the multipliers 3 and 4 in the quadrature detection unit 2 and the low-pass filters 7 and 8. I0 (t) + di, Q0 (t)
+ Dq is sampled by the A / D converters 9 and 10 in a sample value sequence I0 (kT
s) + di, Q0 (kTs) + dq (Ts: sampling period of A / D converters 9 and 10).

Next, I0 (t) + di and Q0 (t) + dq are reception band-limited by reception filters 11 and 12 having root Nyquist characteristics and the like, and baseband signals I (kTs) + di and Q (kTs)
+ Dq is obtained.

In the symbol discrimination point detecting section 13, I (kTs)
+ Di, Q (kTs) + dq to detect symbol identification point information,
The sampling units 14 and 15 detect only the reception filter outputs In and Qn at the symbol discrimination points based on this information and output them. Here, it is assumed that In and Qn are represented by the following equations.

In = Ian + di (10) Qn = Qan + dq (11) Ian, Qan: Baseband signal value at symbol identification point when DC offset is not superimposed DC In the offset detection unit 16, the difference calculation unit
21 and 24, the difference D between In and In-1 is calculated as shown in the following equation.
in and the difference value Dqn between Qn and Qn-1 are calculated.

Din = In−In−1 = Ian−Ian−1 (12) Dqn = Qn−Qn−1 = Qan−Qan−1 (13)

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn as shown in the following equation. ^{Rn = In 2 + Qn 2 =} A 2 +2 (diIan + dqQan) + di 2 + dq 2 ··· (14) A 2 = Ian 2 + Qan 2: squared envelope of the symbol identification point value and difference calculation unit 28 , A difference value Drn between Rn and Rn-1 is calculated as shown in the following equation.

Drn = Rn−Rn−1 = 2 {di (Ian−Ian−1) + dq (Qan−Qan−1)} (15)

Next, the DC offset estimating operation unit 31 performs the operation shown in the following equation using the above Din, Dqn, and Drn, and obtains the estimated values dei, deq of the DC offset as dei = deq. dei = deq = Drn / {2 (Din + Dqn)} = {di (Ian-Ian-1) + dq (Qan-Qan-1)} / (Ian-Ian-1 + Qan-Qan-1) (16)

Now, when diqdq = d0, the above equation (16) becomes as follows, and it can be seen that a correct estimated value can be obtained. dei = deq = Drn / {2 (Din + Dqn)} = {d0 (Ian-Ian-1) + d0 (Qan-Qan-1)} / (Ian-Ian-1 + Qan-Qan-1) = d0 (17) )

On the other hand, In, Qn
Then, the DC offset estimation values dei and deq are subtracted from the above to remove unnecessary DC offset components. The outputs In-dei and Qn-deq of the subtractors 17 and 18 are input to the baseband demodulator 19 and demodulated according to a predetermined demodulation method.

As described above, according to the first embodiment of the present invention, unnecessary DC offset components having the same value are eliminated in the multiplier in the quadrature detector and the low-pass filter for removing the double carrier component. Even in the case of superimposition, the DC offset detection unit detects unnecessary DC offset components from the difference values of the baseband I and Q signals and the difference value of the squared envelope and removes them, thereby performing baseband demodulation processing. A high-precision demodulation process that does not cause distortion in the section can be performed.

(Second Embodiment) FIGS. 1 and 3 are block diagrams showing a configuration of a data receiving apparatus according to a second embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 3 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Din between the in-phase component of the baseband signal at the present time and the in-phase component of the baseband signal one symbol before using the output In of the sampling unit 14, comprising a delay unit 22 between symbols and a subtractor 23. A differential value between the current baseband signal orthogonal component and the immediately preceding symbol baseband signal orthogonal component using the output Qn of the sampling unit 15 comprising an arithmetic unit 21, a delay unit 25 between one symbol and a subtractor 26. A difference operation unit 24 for obtaining Dqn, a square envelope operation unit 27 for obtaining the value Rn of the square envelope at the symbol identification point using the outputs In and Qn of the sampling units 14 and 15, Delay unit 29 for one symbol
And a subtracter 30 for calculating a difference value Drn between the current value of the square envelope and the value of the square envelope one symbol before using the output Rn of the square envelope calculator 27. Part 28
And a DC offset estimation operation unit 31 for calculating the estimated values dei, deq of the DC offset using the outputs Din, Dqn, Drn of the difference operation units 21, 24, 28, and an output dn of the DC offset estimation operation unit 31 And a moving average calculation unit 32 that calculates the moving average value de of dn and outputs the estimated values dei and deq of the DC offset as dei = deq = de.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In and Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21 and 24, the expressions (12) and (1) are used in the same manner as described in the first embodiment.
The difference value Din between In and In-1 represented by 3) and Q
The difference value Dqn between n and Qn-1 is calculated.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation unit 28, as described in the first embodiment, expression (15) is used.
The difference value Drn between Rn and Rn-1 is calculated.

Next, the DC offset estimating operation unit 31 performs the operation shown in the following equation using the above Din, Dqn and Drn to obtain a quasi-estimated value dn of the DC offset. dn = Drn / {2 (Din + Dqn)} = {di (Ian-Ian-1) + dq (Qan-Qan-1)} / (Ian-Ian-1 + Qan-Qan-1) (18)

Next, in order to suppress the influence of the noise contained in the above dn, the moving average calculator 32 calculates a moving average value de of dn as shown in the following equation, and sets dei = deq = de as the DC offset. Are obtained as dei and deq.

[0051]

[Equation 19] dei = deq = de (20) Now, when di ≒ dq = d0, the above equation (20) becomes as follows, and it can be seen that a correct estimated value can be obtained. dei = deq = d0 (21)

As described above, according to the second embodiment of the present invention, unnecessary DC offset components having the same value are eliminated by the multiplier in the quadrature detection unit and the low-pass filter for removing the double carrier component. Even in the case of superimposition, the DC offset detection unit calculates a quasi-estimated value of the DC offset from the difference value of the baseband I and Q signals and the difference value of the squared envelope, and further obtains a moving average value of the result. The effect of noise is suppressed by this,
Calculate the offset estimate and divide it into baseband I, Q
By removing the signal from the signal, it is possible to perform a highly accurate demodulation process in which no distortion occurs in the baseband demodulation processing unit.

(Third Embodiment) FIGS. 1 and 4 are block diagrams showing the configuration of a data receiving apparatus according to a third embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 4 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Din between the in-phase component of the baseband signal at the present time and the in-phase component of the baseband signal one symbol before using the output In of the sampling unit 14, comprising a delay unit 22 between symbols and a subtractor 23. The sampling unit 15 includes an operation unit 21, a moving average operation unit 34 that calculates a moving average value Dein of Din to suppress a noise component included in Din, a delay unit 25 for one symbol, and a subtractor 26. Using the output Qn, a difference operation unit 24 for obtaining a difference value Dqn between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before, and a D / N for suppressing a noise component included in Dqn.
a moving average calculator 35 for calculating a moving average value Deqn of qn;
A square envelope calculating unit 27 for obtaining a square envelope value Rn at a symbol identification point using the outputs In and Qn of the sampling units 14 and 15; a delay unit 29 and a subtractor 30 for one symbol; Consisting of 2
The difference value D between the current value of the squared envelope and the value of the squared envelope one symbol before using the output Rn of the squared envelope calculation unit 27.
rn, a moving average calculator 33 for calculating a moving average value Dern of Drn for suppressing a noise component included in Drn, and an output Dein of the moving average calculators 34, 35, and 33. , Deqn, and Dern, and a DC offset estimating operation unit 36 for calculating DC offset estimated values dei, deq.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In and Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21 and 24, the expressions (12) and (1) are used in the same manner as described in the first embodiment.
The difference value Din between In and In-1 represented by 3) and Q
The difference value Dqn between n and Qn-1 is calculated.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation unit 28, as described in the first embodiment, expression (15) is used.
The difference value Drn between Rn and Rn-1 is calculated.

Next, in order to suppress noise components included in the Din, Dqn, and Drn, moving average values of Din, Dqn, and Drn are calculated by the moving average calculation units 34, 35, and 33 as shown in the following equations. Find Dein, Deqn, and Dern.

[0061]

(Equation 22)

(Equation 23)

(Equation 24)

Next, the DC offset estimating operation unit 36 performs the operation shown in the following equation by using the above-mentioned Dein, Deqn, and Dern, and obtains the DC offset estimated values dei, deq as dei = deq.

[0063]

(Equation 25)

Now, when diqdq = d0, the above equation (25) becomes as follows, and it can be seen that a correct estimated value can be obtained.

[0065]

(Equation 26)

As described above, according to the third embodiment of the present invention, an unnecessary DC offset component having the same value is eliminated in the multiplier in the quadrature detection unit and the low-pass filter for removing the double carrier component. Even in the case of superimposition, the DC offset detection unit uses a moving average value of each of the difference between the baseband I and Q signals and the difference between the squared envelopes to provide a highly reliable DC offset with suppressed noise components. Is calculated from the baseband I and Q signals, so that the baseband demodulation processing unit can perform a highly accurate demodulation process without causing distortion.

(Fourth Embodiment) FIGS. 1 and 5 are block diagrams showing a configuration of a data receiving apparatus according to a fourth embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 5 is a block diagram showing the configuration of the DC offset detection unit 16.
A difference for obtaining a difference value Din between the in-phase component of the baseband signal at the present time and the in-phase component of the baseband signal one symbol before using the output In of the sampling unit 14, comprising a delay unit 22 between symbols and a subtractor 23. The sampling unit 15 includes an operation unit 21, a moving average operation unit 34 that calculates a moving average value Dein of Din to suppress a noise component included in Din, a delay unit 25 for one symbol, and a subtractor 26. Using the output Qn, a difference operation unit 24 for obtaining a difference value Dqn between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before, and a D / N for suppressing a noise component included in Dqn.
a moving average calculator 35 for calculating a moving average value Deqn of qn;
A square envelope calculating unit 27 for obtaining a square envelope value Rn at a symbol identification point using the outputs In and Qn of the sampling units 14 and 15; a delay unit 29 and a subtractor 30 for one symbol; Consisting of 2
The difference value D between the current value of the squared envelope and the value of the squared envelope one symbol before using the output Rn of the squared envelope calculation unit 27.
rn, a moving average calculator 33 for calculating a moving average value Dern of Drn for suppressing a noise component included in Drn, and an output Dein of the moving average calculators 34, 35, and 33. , Deqn, and Dern, to calculate a quasi-estimated value dn of the DC offset,
And the moving average value de of dn is calculated to smooth the output dn of the DC offset estimating operation unit 36, and dei = deq = d
The moving average calculator 32 outputs the DC offset estimated values dei and deq as e.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG. The input In to the DC offset detection unit 16,
Qn is given by the equation (1) in the same manner as described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21 and 24, the expressions (12) and (1) are used in the same manner as described in the first embodiment.
The difference value Din between In and In-1 represented by 3) and Q
The difference value Dqn between n and Qn-1 is calculated.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation unit 28, as described in the first embodiment, expression (15) is used.
The difference value Drn between Rn and Rn-1 is calculated.

Next, in order to suppress the noise components included in the Din, Dqn, and Drn, the moving average calculators 34, 35, and 33 calculate the equation (2) in the same manner as described in the third embodiment.
2), (23), (24), Din, Dqn, D
The moving average values Dein, Deqn, and Dern of rn are obtained.

Next, the DC offset estimating operation unit 36 performs the operation shown in the following equation using the above Dein, Deqn, and Dern to obtain a quasi estimated value dn of the DC offset.

[0075]

[Equation 27]

Further, in order to suppress the influence of the noise included in the above dn, the moving average calculating section 32 calculates a moving average value de of dn as shown in the following equation, and dei = deq = de.
To obtain the DC offset estimated values dei and deq.

[0077]

[Equation 28] dei = deq = de (29) When di ≒ dq = d0, the above equation (29) becomes as follows, and it can be seen that a correct estimated value can be obtained. dei = deq = d0 (30)

As described above, according to the fourth embodiment of the present invention, an unnecessary DC offset component having the same value is eliminated by the multiplier in the quadrature detection unit and the low-pass filter for removing the double carrier component. Even in the case of superimposition, the quasi-estimated value of the DC offset in which the noise component is suppressed is used by the DC offset detection unit using the moving average value of the difference between the baseband I and Q signals and the difference of the squared envelope. , And further calculating a moving average value of the result, thereby calculating a more reliable DC offset estimation value with less variation, and removing this from the baseband I and Q signals to obtain a baseband demodulation process. A high-precision demodulation process that does not cause distortion in the section can be performed.

(Fifth Embodiment) FIGS. 1 and 6 are block diagrams showing a configuration of a data receiving apparatus according to a fifth embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 6 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Di1n between the in-phase component of the current baseband signal and the in-phase component of the baseband signal one symbol before by using the output In of the sampling unit 14, which comprises a delay unit 22 between symbols and a subtractor 23. An in-phase component of a baseband signal one symbol before and two symbols using an output In-1 of a delay unit 22 which is a component of the difference operation unit 21 and includes an arithmetic unit 21, a delay unit 38 for one symbol, and a subtractor 39. A difference calculation unit 3 for obtaining a difference value Di2n between the in-phase components of the previous baseband signal.
7, and a differential value Dq1n between the current baseband signal quadrature component and the baseband signal quadrature component one symbol before using the output Qn of the sampling unit 15, which comprises a delay unit 25 and a subtractor 26 between one symbol. A difference operation unit 24 for obtaining the signal, and an output Qn-1 of the delay unit 25 which is a component of the difference operation unit 24, which is composed of a delay unit 41 and a subtractor 42 for one symbol. Calculation unit 40 for obtaining a difference value Dq2n between the component and the in-phase component of the baseband signal two symbols before, and the squared envelope at the symbol identification point using the outputs In and Qn of the sampling units 14 and 15 Of the current square envelope using the output Rn of the square envelope calculator 27, which is composed of a square envelope calculator 27 for obtaining the value Rn of Difference calculation for finding a difference value Dr1n between the value of the square envelope of one symbol before and Parts 28 and 1
A difference calculation unit 28 comprising a delay unit 44 between symbols and a subtractor 45
Using the output Rn-1 of the delay unit 29, which is a component of the above, to obtain a difference value Dr2n between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before. 43,
Outputs Di1n, Di2 of the difference calculation units 21, 37, 24, 40, 28, 43
and a DC offset estimator 46 for calculating DC offset estimation values dei, deq using n, Dq1n, Dq2n, Dr1n, and Dr2n.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In and Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21, 37, 24, and 40, the difference values Di1n, In-1 of In and In-1 are expressed by the following equations.
Difference value Di2n between Qn and In-2, difference value Dq1n and Qn between Qn and Qn-1
A difference value Dq2n between -1 and Qn-2 is calculated.

Di1n = In−In−1 = Ian−Ian−1 (31) Di2n = In−1−In−2 = Ian−1−Ian−2 (32) Dq1n = Qn−Qn −1 = Qan−Qan−1 (33) Dq2n = Qn−1−Qn−2 = Qan−1−Qan−2 (34) Next, in the square envelope operation unit 27, In, Qn represented by equation (14) as described in the first embodiment.
, The value of the squared envelope is obtained.

Then, the difference calculation sections 28 and 43 calculate the difference value Dr1n between Rn and Rn-1 and the difference value Dr2n between Rn-1 and Rn-2 as shown in the following equations.

Dr1n = Rn−Rn−1 = 2 {di (Ian−Ian−1) + dq (Qan−Qan−1)} (35) Dr2n = Rn−1−Rn−2 = 2 ｛di ( Ian-1−Ian-2) + dq (Qan−1−Qan-2)｝ (36) Next, in the DC offset estimation calculating section 46, the D
By using i1n, Di2n, Dq1n, Dq2n, Dr1n, and Dr2n, an operation shown in the following equation is performed, and the estimated value of the DC offset d
ei = di and deq = dq are obtained.

[0087]

(37)

As described above, according to the fifth embodiment of the present invention, unnecessary DC offset components having different values are used in the multiplier in the quadrature detector and the low-pass filter for removing the double carrier component. Is superimposed even if
In the C offset detection unit, an unnecessary DC is obtained from the difference between the baseband I and Q signals and the difference between the squared envelopes.
By detecting and removing the offset component, it is possible to perform high-precision demodulation processing without causing distortion in the baseband demodulation processing unit.

(Sixth Embodiment) FIGS. 1 and 7 are block diagrams showing a configuration of a data receiving apparatus according to a sixth embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 7 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Di1n between the in-phase component of the current baseband signal and the in-phase component of the baseband signal one symbol before by using the output In of the sampling unit 14, which comprises a delay unit 22 between symbols and a subtractor 23. An in-phase component of a baseband signal one symbol before and two symbols using an output In-1 of a delay unit 22 which is a component of the difference operation unit 21 and includes an arithmetic unit 21, a delay unit 38 for one symbol, and a subtractor 39. A difference calculation unit 3 for obtaining a difference value Di2n between the in-phase components of the previous baseband signal.
7, and a differential value Dq1n between the current baseband signal quadrature component and the baseband signal quadrature component one symbol before using the output Qn of the sampling unit 15, which comprises a delay unit 25 and a subtractor 26 between one symbol. A difference operation unit 24 for obtaining the signal, and an output Qn-1 of the delay unit 25 which is a component of the difference operation unit 24, which is composed of a delay unit 41 and a subtractor 42 for one symbol. Calculation unit 40 for obtaining a difference value Dq2n between the component and the in-phase component of the baseband signal two symbols before, and the squared envelope at the symbol identification point using the outputs In and Qn of the sampling units 14 and 15 Of the current square envelope using the output Rn of the square envelope calculator 27, which is composed of a square envelope calculator 27 for obtaining the value Rn of Difference calculation for finding a difference value Dr1n between the value of the square envelope of one symbol before and Parts 28 and 1
A difference calculation unit 28 comprising a delay unit 44 between symbols and a subtractor 45
Using the output Rn-1 of the delay unit 29, which is a component of the above, to obtain a difference value Dr2n between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before. 43,
Outputs Di1n, Di2 of the difference calculation units 21, 37, 24, 40, 28, 43
n, Dq1n, Dq2n, Dr1n, and a DC offset estimation calculator 46 for calculating DC offset estimation values dxn and dyn using Dr2n, and an output dxn of the DC offset estimation calculator.
The moving average calculator 47 calculates a moving average value of dxn to smooth the output, and outputs the result as an estimated value of DC offset dei. A moving average calculator 48 calculates a moving average value and outputs the result as an estimated DC offset value deq.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In and Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21, 37, 24, and 40, the equation (3) is used in the same manner as described in the fifth embodiment.
In) represented by 1), (32), (33), and (34)
Difference value Di1n between In-1 and In-1, difference value Di2n between In-1 and In-2,
The difference value Dq1n between Qn and Qn-1 and the difference value Dq2n between Qn-1 and Qn-2
Are calculated respectively.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation units 28 and 43, the equations (35) and (3) are used in the same manner as described in the fifth embodiment.
6), the difference value Dr1n between Rn and Rn-1, Rn-1 and R
The difference value Dr2n of n-2 is calculated.

Next, in the DC offset estimation calculating section 46, the above-mentioned Di1n, Di2n, Dq1n, Dq2n, Dr1n, Dr2n
Is used to perform quasi-estimated values dxn and dyn of the DC offset.

[0097]

(38)

Next, in order to suppress the influence of noise included in the above dxn and dy, moving average calculators 47 and 48 calculate the moving average values of dxn and dy as shown in the following equations, and calculate the results. The DC offset is output as the estimated value dei, deq.

[0099]

[Equation 39]

(Equation 40)

As described above, according to the sixth embodiment of the present invention, unnecessary DC offset components having different values in the multiplier in the quadrature detector and the low-pass filter for removing the double carrier component are used. Is superimposed even if
The C offset detection unit calculates a quasi-estimated value of the DC offset from the difference value between the baseband I and Q signals and the difference value of the squared envelope, and further obtains a moving average value of the result, whereby the influence of noise is obtained. , And a more reliable DC offset estimation value is calculated and removed from the baseband I and Q signals, so that the baseband demodulation processing unit can perform highly accurate demodulation processing without causing distortion. it can.

(Seventh Embodiment) FIGS. 1 and 8 are block diagrams showing a configuration of a data receiving apparatus according to a seventh embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation, and therefore, only the configuration and operation of the DC offset detection unit 16 will be described here.

FIG. 8 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Di1n between the in-phase component of the current baseband signal and the in-phase component of the baseband signal one symbol before by using the output In of the sampling unit 14, which comprises a delay unit 22 between symbols and a subtractor 23. An in-phase component of a baseband signal one symbol before and two symbols using an output In-1 of a delay unit 22 which is a component of the difference operation unit 21 and includes an arithmetic unit 21, a delay unit 38 for one symbol, and a subtractor 39. A difference calculation unit 3 for obtaining a difference value Di2n between the in-phase components of the previous baseband signal.
7, and a differential value Dq1n between the current baseband signal quadrature component and the baseband signal quadrature component one symbol before using the output Qn of the sampling unit 15, which comprises a delay unit 25 and a subtractor 26 between one symbol. A difference operation unit 24 for obtaining the signal, and an output Qn-1 of the delay unit 25 which is a component of the difference operation unit 24, which is composed of a delay unit 41 and a subtractor 42 for one symbol. Calculation unit 40 for obtaining a difference value Dq2n between the component and the in-phase component of the baseband signal two symbols before, and the squared envelope at the symbol identification point using the outputs In and Qn of the sampling units 14 and 15 Of the current square envelope using the output Rn of the square envelope calculator 27, which is composed of a square envelope calculator 27 for obtaining the value Rn of Difference calculation for finding a difference value Dr1n between the value of the square envelope of one symbol before and Parts 28 and 1
A difference calculation unit 28 comprising a delay unit 44 between symbols and a subtractor 45
Using the output Rn-1 of the delay unit 29, which is a component of the above, to obtain a difference value Dr2n between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before. 43,
A moving average calculation unit 51 that calculates a moving average value Di1n of Di1n to suppress noise components included in Di1n, and a moving average calculation that calculates a moving average value Di2n of Di2n to suppress noise components included in Di2n. Unit 52, and a moving average value Deq1n of Dq1n for suppressing a noise component included in Dq1n.
, A moving average calculator 54 that calculates a moving average value Deq2n of Dq2n to suppress the noise component included in Dq2n, and a moving average calculator 53 that suppresses the noise component included in Dr1n. A moving average calculating section 49 for calculating a moving average value Der1n; a moving average calculating section 50 for calculating a moving average value Der2n of Dr2n for suppressing a noise component included in Dr2n; and a moving average calculating section 51, 52, 53 , 54, 49, 50 outputs Dei1n, Dei2n, Deq1n, Deq2n, Der1n, Der2n
And a DC offset estimating calculation unit 55 for calculating the estimated values dei and deq of the DC offset by using.

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In, Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21, 37, 24, and 40, the equation (3) is used in the same manner as described in the fifth embodiment.
In) represented by 1), (32), (33), and (34)
Difference value Di1n between In-1 and In-1, difference value Di2n between In-1 and In-2,
The difference value Dq1n between Qn and Qn-1 and the difference value Dq2n between Qn-1 and Qn-2
Are calculated respectively.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation units 28 and 43, the equations (35) and (3) are used in the same manner as described in the fifth embodiment.
6), the difference value Dr1n between Rn and Rn-1, Rn-1 and R
The difference value Dr2n of n-2 is calculated.

Next, the above Di1n, Di2n, Dq1n, Dq2n,
In order to suppress noise components included in Dr1n and Dr2n, the moving average calculation units 51, 52, 53, 54, 49, and 50 calculate Di1n, Di2n, Dq1n, Dq2n, Dr1n, and Dr2n as shown in the following equations.
Moving average values Dei1n, Dei2n, Deq1n, Deq2n,
Der1n and Der2n are obtained.

[0109]

[Equation 41]

(Equation 42)

[Equation 43]

[Equation 44]

[Equation 45]

[Equation 46]

Next, in the DC offset estimating calculation unit 55, the above Dei1n, Dei2n, Deq1n, Deq2n, Der1n, D
Using er2n, an operation as shown in the following equation is performed to obtain DC offset estimated values dei = di and deq = dq.

[0111]

[Equation 47]

As described above, according to the seventh embodiment of the present invention, unnecessary DC offset components having different values are used in the multiplier in the quadrature detector and the low-pass filter for removing the double carrier component. Is superimposed even if
The C offset detection unit calculates the estimated value of the DC offset with the noise component suppressed and high reliability using the moving average value of each of the difference between the baseband I and Q signals and the difference between the square envelopes. However, by removing this from the baseband I and Q signals, it is possible to perform high-precision demodulation without distortion in the baseband demodulation processing unit.

(Eighth Embodiment 8) FIGS. 1 and 9 show an eighth embodiment.
FIG. 3 is a block diagram illustrating a configuration of a data receiving device according to an embodiment. The components other than the DC offset detection unit 16 in FIG. 1 have the same configuration as the first embodiment and perform the same operation.
Only the configuration and operation will be described.

FIG. 9 is a block diagram showing the configuration of the DC offset detecting section 16.
A difference for obtaining a difference value Di1n between the in-phase component of the current baseband signal and the in-phase component of the baseband signal one symbol before by using the output In of the sampling unit 14, which comprises a delay unit 22 between symbols and a subtractor 23. An in-phase component of a baseband signal one symbol before and two symbols using an output In-1 of a delay unit 22 which is a component of the difference operation unit 21 and includes an arithmetic unit 21, a delay unit 38 for one symbol, and a subtractor 39. A difference calculation unit 3 for obtaining a difference value Di2n between the in-phase components of the previous baseband signal.
7, and a differential value Dq1n between the current baseband signal quadrature component and the baseband signal quadrature component one symbol before using the output Qn of the sampling unit 15, which comprises a delay unit 25 and a subtractor 26 between one symbol. A difference operation unit 24 for obtaining the signal, and an output Qn-1 of the delay unit 25 which is a component of the difference operation unit 24, which is composed of a delay unit 41 and a subtractor 42 for one symbol. Calculation unit 40 for obtaining a difference value Dq2n between the component and the in-phase component of the baseband signal two symbols before, and the squared envelope at the symbol identification point using the outputs In and Qn of the sampling units 14 and 15 Of the current square envelope using the output Rn of the square envelope calculator 27, which is composed of a square envelope calculator 27 for obtaining the value Rn of Difference calculation for finding a difference value Dr1n between the value of the square envelope of one symbol before and Parts 28 and 1
A difference calculation unit 28 comprising a delay unit 44 between symbols and a subtractor 45
Using the output Rn-1 of the delay unit 29, which is a component of the above, to obtain a difference value Dr2n between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before. 43,
A moving average calculation unit 51 that calculates a moving average value Di1n of Di1n to suppress noise components included in Di1n, and a moving average calculation that calculates a moving average value Di2n of Di2n to suppress noise components included in Di2n. Unit 52, and a moving average value Deq1n of Dq1n for suppressing a noise component included in Dq1n.
, A moving average calculator 54 that calculates a moving average value Deq2n of Dq2n to suppress the noise component included in Dq2n, and a moving average calculator 53 that suppresses the noise component included in Dr1n. A moving average calculating section 49 for calculating a moving average value Der1n; a moving average calculating section 50 for calculating a moving average value Der2n of Dr2n for suppressing a noise component included in Dr2n; and a moving average calculating section 51, 52, 53 , 54, 49, 50 outputs Dei1n, Dei2n, Deq1n, Deq2n, Der1n, Der2n
Is used to calculate the quasi-estimated values dxn and dyn of the DC offset, and the moving average value of dxn is calculated to smooth the output dxn of the DC offset estimation calculation unit. Is the estimated value of the DC offset d
The moving average calculator 47 outputs the moving average value of dy to smooth the output dy of the DC offset estimating calculator, and outputs the result as the estimated DC offset value deq
And a moving average calculation unit 48 that outputs the results as

The operation of the DC offset detecting section 16 of the data receiving apparatus configured as described above will be described with reference to FIG.

Inputs In and Qn to DC offset detector 16
Is the same as the equation (1) described in the first embodiment.
0) and (11).

Then, in the difference calculation units 21, 37, 24, and 40, the equation (3) is used in the same manner as described in the fifth embodiment.
In) represented by 1), (32), (33), and (34)
Difference value Di1n between In-1 and In-1, difference value Di2n between In-1 and In-2,
The difference value Dq1n between Qn and Qn-1 and the difference value Dq2n between Qn-1 and Qn-2
Are calculated respectively.

Next, in the square envelope calculating section 27, the value of the square envelope is obtained from In and Qn expressed by the equation (14) in the same manner as described in the first embodiment. .

In the difference calculation units 28 and 43, the equations (35) and (3) are used in the same manner as described in the fifth embodiment.
6), the difference value Dr1n between Rn and Rn-1, Rn-1 and R
The difference value Dr2n of n-2 is calculated.

Next, the above Di1n, Di2n, Dq1n, Dq2n,
In order to suppress the noise components included in Dr1n and Dr2n, the moving average calculation units 51, 52, 53, 54, 49, and 50 use the equations (41) and (41) in the same manner as described in the seventh embodiment. 4
2) Moving averages De1n, Dei2n, Deq1n, Deq2n, Der of Di1n, Di2n, Dq1n, Dq2n, Dr1n, and Dr2n represented by (43), (44), (45), and (46).
1n and Der2n are obtained.

Next, in the DC offset estimating calculation unit 55, the above Dei1n, Dei2n, Deq1n, Deq2n, Der1n, D
Using er2n, an operation as shown in the following equation is performed to obtain quasi-estimated values dxn and dyn of the DC offset.

[0122]

[Equation 48]

Next, in order to suppress the influence of noise contained in the above dxn and dyn, the moving average calculation units 47 and 48 calculate the moving average values of dxn and dyn as shown in the following equations, and The DC offset is output as the estimated value dei, deq.

[0124]

[Equation 49]

[Equation 50]

As described above, according to the eighth embodiment of the present invention, unnecessary DC offset components having different values in a multiplier in a quadrature detection unit and a low-pass filter for removing a double carrier component are used. Is superimposed even if
The C offset detection unit calculates a quasi-estimated value of the DC offset with the noise component suppressed, using the moving average value of each of the difference between the baseband I and Q signals and the difference between the square envelopes. By calculating the moving average value of the result, a more reliable DC offset estimation value with less variation is calculated, and by removing this from the baseband I and Q signals, distortion in the baseband demodulation processing unit is reduced. High precision demodulation can be performed.

[0126]

As described above, according to the present invention, even when an unnecessary DC offset component is superimposed on a multiplier in a quadrature detector or a low-pass filter for removing a double carrier component, a new component is provided. The DC offset detection unit detects unnecessary DC offset components from the difference values of the baseband I and Q signals and the difference value of the squared envelope and removes them, so that distortion in the baseband demodulation processing unit is reduced. The effect that a highly accurate demodulation process that does not occur can be performed is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a data receiving apparatus common to a first embodiment to an eighth embodiment of the present invention;

FIG. 2 is a diagram showing a configuration of a DC offset detection unit according to the first embodiment of the present invention;

FIG. 3 is a diagram illustrating a configuration of a DC offset detection unit according to a second embodiment of the present invention;

FIG. 4 is a diagram showing a configuration of a DC offset detection unit according to a third embodiment of the present invention;

FIG. 5 is a diagram illustrating a configuration of a DC offset detection unit according to a fourth embodiment of the present invention;

FIG. 6 is a diagram illustrating a configuration of a DC offset detection unit according to a fifth embodiment of the present invention;

FIG. 7 is a diagram illustrating a configuration of a DC offset detection unit according to a sixth embodiment of the present invention;

FIG. 8 is a diagram showing a configuration of a DC offset detection unit according to a seventh embodiment of the present invention;

FIG. 9 is a diagram illustrating a configuration of a DC offset detection unit according to an eighth embodiment of the present invention;

FIG. 10 is a diagram showing a configuration of a conventional data receiving device.

[Explanation of symbols]

 Reference Signs List 1 received signal input terminal 2 quadrature detector 3, 4 multiplier 5 π / 2 phase shifter 6 local oscillator 7, 8 low-pass filter 9, 10 A / D converter 11, 12 reception filter 13 symbol identification point detector 14, 15 Sampling unit 16 DC offset detection unit 17, 18 Subtraction unit 19 Baseband demodulation processing unit 20 Decoded data output terminal 21, 24, 28, 37, 40, 43 Difference calculation unit 22, 25, 29, 38, 41, 44 Delay unit 23, 26, 30, 39, 42, 45 Subtractor 27 Square envelope operation unit 32-35, 47-54 Moving average operation unit 31, 36, 46, 55 DC offset estimation operation unit

Claims (8)

[Claims] 1. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal to detect an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculation unit for obtaining a difference value Di between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; The difference value Dq between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit.
A second difference operation unit for obtaining the value of the first and second sampling units, and a square envelope operation unit for obtaining the value of the square envelope at the symbol identification point using the outputs of the first and second sampling units. A third difference calculation unit for obtaining a difference value Dr between the current value of the square envelope and the value of the square envelope one symbol before using the output of the square envelope calculation unit; Using the outputs Di, Dq, and Dr of the first, second, and third difference calculation units, d = Dr / (2 (D
i + Dq)), and includes a DC offset estimating calculation unit that outputs DC offset estimated values dei and deq as dei = deq = d, and a first and a second multiplier in the quadrature detection unit and the first and second multipliers. , Even when unnecessary DC offset components having the same value are superimposed in the second low-pass filter,
A data receiving apparatus, wherein the DC offset detecting section detects and removes the DC offset. 2. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal to detect an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculation unit for obtaining a difference value Di between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; The difference value Dq between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit.
A second difference operation unit for obtaining the value of the first and second sampling units, and a square envelope operation unit for obtaining the value of the square envelope at the symbol identification point using the outputs of the first and second sampling units. A third difference calculation unit for obtaining a difference value Dr between the current value of the square envelope and the value of the square envelope one symbol before using the output of the square envelope calculation unit; Using the outputs Di, Dq, and Dr of the first, second, and third difference calculation units, d = Dr / (2 (D
i + Dq)), and a DC offset estimator for calculating and outputting a moving average value d of d for smoothing the output d of the DC offset estimator, and dei = deq = de
A moving average calculation unit that outputs DC offset estimation values dei and deq, and unnecessary DCs of the same value in the first and second multipliers and the first and second low-pass filters in the quadrature detection unit. A data receiving apparatus wherein, even when an offset component is superimposed, the DC offset detection unit detects and removes the offset component. 3. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal and detecting an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculating unit for calculating a difference value between a current baseband signal in-phase component and a baseband signal in-phase component one symbol before using the output of the first sampling unit; A second difference calculation unit for obtaining a difference value between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit; A square envelope calculating unit for obtaining the value of the square envelope at the symbol discrimination point using the output of the sampling unit, and the current square envelope using the output of the square envelope calculating unit. A third difference calculation unit for obtaining a difference value between the value of the line and the value of the square envelope of one symbol before, and a moving average value of outputs of the first, second, and third difference calculation units First, second, and third moving average calculators for calculating Dei, Deq, and Der; 2, third moving average calculating unit outputs Dei of, Deq, using Der d = D
er / (2 (Dei + Deq)) is calculated, and dei = deq = d
Which outputs the estimated values of DC offset dei, deq as
A C offset estimating operation unit, wherein the DC offset is maintained even when unnecessary DC offset components having the same value are superimposed on the first and second multipliers in the quadrature detection unit and the first and second low-pass filters. A data receiving device, wherein the data is detected and removed by a detection unit. 4. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal to detect an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculating unit for calculating a difference value between a current baseband signal in-phase component and a baseband signal in-phase component one symbol before using the output of the first sampling unit; A second difference calculation unit for obtaining a difference value between the current baseband signal orthogonal component and the baseband signal orthogonal component one symbol before using the output of the second sampling unit; A square envelope calculating unit for obtaining the value of the square envelope at the symbol discrimination point using the output of the sampling unit, and the current square envelope using the output of the square envelope calculating unit. A third difference calculation unit for obtaining a difference value between the value of the line and the value of the square envelope of one symbol before, and a moving average value of outputs of the first, second, and third difference calculation units First, second, and third moving average calculators for calculating Dei, Deq, and Der; 2, third moving average calculating unit outputs Dei of, Deq, using Der d = D
er / (2 (Dei + Deq)), and a DC offset estimator for calculating and outputting a moving average value de of d for smoothing the output d of the DC offset estimator, and dei = deq = estimated value of DC offset de as de
a fourth moving average calculator for outputting i, deq, and a first and second multiplier in the quadrature detector;
A data receiving apparatus characterized in that, even when unnecessary DC offset components having the same value are superimposed on each other in the second low-pass filter, the DC offset detection unit detects and removes the unnecessary DC offset components. 5. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal to detect an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculation unit for obtaining a difference value Di1 between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; and A second difference calculator for calculating a difference value Di2 between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before, and the output of the second sampling unit. A third difference calculation unit for calculating a difference value Dq1 between the current baseband signal orthogonal component and the immediately preceding baseband signal orthogonal component, and a third symbol preceding baseband signal orthogonal component and the second symbol preceding symbol A fourth difference calculating unit for obtaining a difference value Dq2 between the orthogonal components of the baseband signal, and a value of a square envelope at a symbol identification point using an output of the first and second sampling units. 2 to ask And a fifth unit for obtaining a difference value Dr1 between the current value of the square envelope and the value of the square envelope of one symbol before using the output of the square envelope operation unit and the output of the square envelope operation unit. A difference operation unit, and
A sixth difference calculation unit for obtaining a difference value Dr2 between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before, and the first, second, third, and second 4. Using the outputs Di1, Di2, Dq1, Dq2, Dr1, and Dr2 of the fifth and sixth difference calculation units, Di1 has one row and one column, Dq1 has one row and two columns, and Di2 has two rows and one.
The inverse matrix C ^-1 of the matrix C having two columns and Dq2 as 2 rows and 2 columns is obtained, and (dei, deq) ^T = C ^-1 (Dr1, Dr2) ^T is calculated. A DC offset estimating operation unit that outputs an estimated value, and unnecessary DC offset components of different values are superimposed on the first and second multipliers in the quadrature detection unit and the first and second low-pass filters. In this case, even in such a case, the DC offset detecting section detects and removes the detected DC offset. 6. A received signal input terminal for receiving a received RF signal or a frequency-converted received IF signal, and a local oscillator for frequency-converting the received signal and detecting an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculation unit for obtaining a difference value Di1 between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; and A second difference calculator for calculating a difference value Di2 between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before, and the output of the second sampling unit. A third difference calculation unit for calculating a difference value Dq1 between the current baseband signal orthogonal component and the immediately preceding baseband signal orthogonal component, and a third symbol preceding baseband signal orthogonal component and the second symbol preceding symbol A fourth difference calculating unit for obtaining a difference value Dq2 between the orthogonal components of the baseband signal, and a value of a square envelope at a symbol identification point using an output of the first and second sampling units. 2 to ask And a fifth unit for obtaining a difference value Dr1 between the current value of the square envelope and the value of the square envelope of one symbol before using the output of the square envelope operation unit and the output of the square envelope operation unit. A difference operation unit, and
A sixth difference calculation unit for obtaining a difference value Dr2 between the value of the square envelope of one symbol before and the value of the square envelope of two symbols before, and the first, second, third, and second 4. Using the outputs Di1, Di2, Dq1, Dq2, Dr1, and Dr2 of the fifth and sixth difference calculation units, Di1 has one row and one column, Dq1 has one row and two columns, and Di2 has two rows and one.
A DC offset estimating operation unit for obtaining an inverse matrix C ⁻¹ of a matrix C having columns and Dq2 as 2 rows and 2 columns, further calculating (dx, dy) ^T = C ⁻¹ (Dr1, Dr2) ^T and outputting , D in order to smooth the outputs dx and dy of the DC offset estimator
It comprises first and second moving average calculators for calculating moving averages dei, deq of x and dy and outputting the moving averages as estimated values of DC offset, and first and second multipliers in the quadrature detector. A data receiving apparatus wherein, even when unnecessary DC offset components having different values are superimposed in the first and second low-pass filters, the DC offset detection unit detects and removes them. 7. A reception signal input terminal for inputting a reception RF signal or a frequency-converted reception IF signal, and a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculating unit for obtaining a difference value between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; and A second difference calculation unit for calculating a difference value between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before, and a current value obtained by using an output of the second sampling unit. A third difference calculator for calculating a difference value between the orthogonal component of the baseband signal and the orthogonal component of the baseband signal one symbol before, and the orthogonal component of the baseband signal one symbol before and the baseband signal two symbols before A fourth difference calculation unit for obtaining a difference value between orthogonal components, the first and second difference calculation units;
A square envelope calculating unit for obtaining the value of the square envelope at the symbol discrimination point using the output of the sampling unit, and the current square envelope using the output of the square envelope calculating unit And the value of 1
A fifth difference calculating unit for obtaining a difference value between the value of the square envelope before the symbol and the value of the square envelope before the symbol and the value of the square envelope before the second symbol; And a moving average value Dei1, Dei2, Deq1, Deq2 of the outputs of the first, second, third, fourth, fifth, and sixth difference calculation units. , Der1, Der2, first, second, third, fourth, fifth, and sixth moving average calculators, and the first, second, third, fourth, fifth, and sixth moving average calculators. Output Dei1, Dei2, Deq1, Deq2, Der of the moving average calculation unit
1, Dei1 is 1 row and 1 column, Deq1 is 1 row and 2 columns using Der2,
An inverse matrix C ⁻¹ of a matrix C having Dei2 as 2 rows and 1 column and Deq2 as 2 rows and 2 columns is obtained, and (dei, deq) ^T = C ⁻¹ (Dr
1, a Dr2) ^T, and a DC offset estimating operation unit for outputting dei and deq as DC offset estimation values,
Even when unnecessary DC offset components having different values are superimposed in the first and second multipliers in the quadrature detection unit and the first and second low-pass filters, the DC offset detection unit detects this. A data receiving device characterized by removing. 8. A reception signal input terminal for inputting a reception RF signal or a reception IF signal subjected to frequency conversion, and a local oscillator for frequency-converting the reception signal and detecting an in-phase component I and a quadrature component Q of a baseband. , A first and a second multiplier, a quadrature detector comprising a π / 2 phase shifter, and a first and a second detector for removing a double carrier component contained in the in-phase and quadrature outputs of the quadrature detector. A second low-pass filter; first and second A / D converters for converting outputs of the first and second low-pass filters into digital signals; and the first and second A / D converters First and second receiving filters for limiting a receiving band of an output signal of the filter, and the first and second receiving filters
A symbol discriminating point detecting unit for detecting a symbol discriminating point from the output of the receiving filter, and a first detecting unit that detects only a receiving filter output at the symbol discriminating point based on the discriminating point information obtained by the symbol discriminating point detecting unit. , A second sampling unit, a DC offset detection unit for detecting an unnecessary DC offset component contained therein by using outputs of the first and second sampling units as described later, and the DC offset detection. First and second subtraction sections for subtracting unnecessary DC offset components dei and deq detected by the sections from the outputs of the first and second sampling sections, and the first and second subtraction sections. A demodulation unit for demodulating the output of the baseband demodulation unit, and a decoded data output terminal for detecting the decoded data output from the baseband demodulation processing unit; A first difference calculating unit for obtaining a difference value between the current baseband signal in-phase component and the baseband signal in-phase component one symbol before using the output of the first sampling unit; and A second difference calculation unit for calculating a difference value between the in-phase component of the baseband signal one symbol before and the in-phase component of the baseband signal two symbols before, and a current value obtained by using an output of the second sampling unit. A third difference calculator for calculating a difference value between the orthogonal component of the baseband signal and the orthogonal component of the baseband signal one symbol before, and the orthogonal component of the baseband signal one symbol before and the baseband signal two symbols before A fourth difference calculation unit for obtaining a difference value between orthogonal components, the first and second difference calculation units;
A square envelope calculating unit for obtaining the value of the square envelope at the symbol discrimination point using the output of the sampling unit, and the current square envelope using the output of the square envelope calculating unit And the value of 1
A fifth difference calculating unit for obtaining a difference value between the value of the square envelope before the symbol and the value of the square envelope before the symbol and the value of the square envelope before the second symbol; And a moving average value Dei1, Dei2, Deq1, Deq2 of the outputs of the first, second, third, fourth, fifth, and sixth difference calculation units. , Der1, Der2, first, second, third, fourth, fifth, and sixth moving average calculators, and the first, second, third, fourth, fifth, and sixth moving average calculators. Output Dei1, Dei2, Deq1, Deq2, Der of the moving average calculation unit
1, Dei1 is 1 row and 1 column, Deq1 is 1 row and 2 columns using Der2,
An inverse matrix C ⁻¹ of a matrix C having Dei2 as 2 rows and 1 column and Deq2 as 2 rows and 2 columns is obtained, and (dx, dy) ^T = C ⁻¹ (Dr
1, Dr2) DC offset estimating operation unit for calculating and outputting ^T, and moving average values dei, deq of dx, dy for smoothing the outputs dx, dy of the DC offset estimating operation unit, and calculating this by DC Seventh, which is output as an estimated value of the offset,
An eighth moving average calculation unit is provided, and even when unnecessary DC offset components having different values are superimposed on the first and second multipliers in the quadrature detection unit and the first and second low-pass filters, A data receiving apparatus, wherein the DC offset detecting section detects and removes the DC offset.