JP3518848B2 - Phase control method for quadrature modulator and quadrature demodulator and communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimum quadrature modulator and quadrature demodulator used in, for example, a digital mobile communication device, and a control method for calibrating a phase error thereof.

[0002]

2. Description of the Related Art A linear modulation system is widely used in digital mobile communication, and a quadrature modulator and a quadrature demodulator are used to perform the modulation and demodulation.

FIG. 5 shows an example of a communication device including a quadrature modulator and a quadrature demodulator. FIG. 5 is a block diagram showing an example of the configuration of a communication device including a quadrature modulator and a quadrature demodulator. 1-1 and 1-2 are input terminals on the transmitting side, 1-3 are input terminals on the receiving side, 2-1 and 2-2 are output terminals on the receiving side, 2-3 is output terminals on the transmitting side, and 5 is Carrier wave oscillator, 6-1, 6-2, 6-3, 6-4
Are multipliers, 7-1 and 7-2 are 90-degree phase shifters, 9 is an adder, and 3 is multipliers 6-1, 6-2 and 90-degree phase shifter 7-1 and adder 9. A quadrature modulator, 4 is a quadrature demodulator composed of multipliers 6-3 and 6-4 and a 90-degree phase shifter 7-2. In FIG. 5, on the transmitting side, first, the in-phase component (I component) of the baseband signal is input to the input terminal 1-1, and the quadrature-phase component (Q component) of the baseband signal is input to the input terminal 1-2. The signals are sent to the multipliers 6-1 and 6-2 of the quadrature modulator 3, respectively. The input signals (I component and Q component) and the carrier waves separately sent from the carrier wave oscillator 5 are input to the multipliers 6-1 and 6-2, and the input carrier wave and the I component or Q component of the input signal are input. And send them to the adder 9. The adder 9 adds the two input signals, outputs the added signal, and sends it to the high-frequency circuit via the output terminal 2-3. At this time, the carrier wave of the required frequency oscillated by the carrier wave oscillator 5 is directly input to the multiplier 6-1 and is input to the multiplier 6-2 via the 90-degree phase shifter 7-1. The 90-degree phase shifter 7-1 shifts the phase of the input carrier wave by 90 degrees and outputs it to the multiplier 6-2.

On the other hand, on the receiving side, the received signal input from the input terminal 1-3 is input to the multiplier 6-3 and the multiplier 6-4. The multiplier 6-3 multiplies the input signal by the separately input carrier wave and outputs the I component via the output terminal 2-1. Multiplier 6-4
Is an output terminal that multiplies the input signal by the separately input carrier wave.
Output the Q component via 2. The quadrature demodulator 4 is supplied with the carrier wave of a predetermined frequency oscillated by the carrier wave oscillator 5, and is inputted to the multiplier 6-3 and the 90-degree phase shifter 7-2, and the 90-degree phase shifter 7-
2 shifts the phase of the input carrier wave by 90 degrees and outputs it to the multiplier 6-4.

In the above-mentioned conventional technique, in the quadrature modulator 3, when the carrier wave is quadrature-modulated by the two signals of the I component and the Q component, the phase error due to the 90-degree phase shifter causes the deterioration of the modulation accuracy. . Further, in the quadrature demodulator 4, when quadrature demodulating the two signals of the I component and the Q component by the carrier wave, the demodulation accuracy is deteriorated due to the phase error caused by the 90-degree phase shifter. Due to the deterioration of the modulation accuracy and the demodulation accuracy, the data error rate of the communication device increases and the communication quality deteriorates. For example, FIG. 6 is a diagram for explaining the relationship between the phase error of the 90-degree phase shifter and the deterioration of modulation / demodulation accuracy. The horizontal axis is the I component (I axis), the vertical axis is the Q component (Q axis), A
Is an ideal identification point, A ′ is an actual signal point, Δθ is a phase error, and the Q ′ axis is the axial direction when the phase error Δθ is present. In FIG. 6, when the Q axis has a phase error Δθ with respect to the I axis as shown by the vector diagram of the I component-Q component orthogonal coordinates (the Q axis at this time is defined as the Q ′ axis), it is ideal. Since the identification point A (vector OA) is moved to the identification point A ′ (vector OA ′), the error vector AA ′ deteriorates the modulation accuracy or the demodulation accuracy. Therefore, in a communication device provided with a quadrature modulator and a quadrature demodulator that generate such a phase error, it is necessary to correct the phase in the quadrature modulator and the quadrature demodulator to improve the deterioration of the received data error rate. Conventionally, the phase accuracy of a 90-degree phase shifter depends on the accuracy of its manufacturing process, and it is designed to have versatility and allow a certain error so that it can be used in a wide band. The phase error differs depending on the frequency band to be used. In addition, the phase error of the 90-degree phase shifter changes over time and its phase error changes, which further deteriorates the modulation accuracy and demodulation accuracy.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Due to manufacturing variations of 90-degree phase shifters, temperature characteristics, and phase errors due to aging, the modulation accuracy and demodulation accuracy deteriorate.

An object of the present invention is to eliminate the above-mentioned drawbacks, control the phase error in the quadrature modulator and the quadrature demodulator to be zero, and improve the deterioration of the received data error rate. An object is to provide a quadrature demodulator and a phase control method thereof.

[0008]

In order to achieve the above object, a quadrature modulator and a quadrature demodulator of the present invention are provided in a communication device including a quadrature modulator and a quadrature demodulator for performing digital signal processing. , A first carrier wave on the I component side of the signal input to the quadrature modulator and a second carrier wave on the Q component side
A first phase shifting means for adjusting the phase difference between the carrier and the carrier by the control signal, and a third carrier for multiplying the I component side to be multiplied by the quadrature demodulator in order to output the quadrature demodulated signal from the quadrature demodulator. The second phase shift means for adjusting the phase difference between the fourth carrier wave multiplied to the Q component side by the control signal and the phase error detected from the I component and Q component signals output from the quadrature demodulator The control means includes a detector that outputs information and a control means that outputs a control signal to the first phase shift means and the second phase shift means based on the error information output from the detector to perform phase control. Controls the first phase shifting means so that the phase difference of the carrier wave multiplied by the quadrature modulator becomes 90 degrees from the phase error signal detected from the I component and Q component signals of the quadrature demodulator output, and the quadrature demodulation is performed. The second phase shift so that the phase difference of the carrier wave is 90 degrees. It is a controlled means.

The phase control method for the quadrature modulator and the quadrature demodulator according to the present invention is a signal having a predetermined amplitude in one of the input I component and the input Q component of the signal input to the quadrature modulator and a signal having zero amplitude in the other. To control the second phase shift means first, and then for the input I component and input Q component signals input to the quadrature modulator, when controlling the second phase shift means, zero amplitude is applied. A predetermined amplitude is given to the input component, and the first phase shift means is controlled by setting the amplitude of the input component given the predetermined amplitude to zero when controlling the second phase shift means. is there.

Furthermore, in the communication device including the quadrature modulator and the quadrature demodulator of the present invention, a means for feeding back a part of the output signal of the quadrature modulator as a feedback signal, and the feedback signal and the quadrature demodulator A demodulation input signal for demodulation is input, and one of the feedback signal and the demodulation input signal is switched by the control means and output to the quadrature demodulator.

In addition, in a communication device having a quadrature modulator and a quadrature demodulator according to the present invention, and having a transmitter for feeding back a part of the output of the power amplifier to compensate for the non-linear distortion of the power amplifier, the feedback signal is quadratured. The I / Q and Q component signals demodulated in the demodulator are input, and a control means for adjusting the phase error between the quadrature modulator and the quadrature demodulator is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a phase control method for a quadrature modulator and a quadrature demodulator according to the present invention will be described with reference to FIGS. 1, 2 and 4. FIG. 1 is a block diagram of a quadrature demodulator and a quadrature demodulator of a communication device that implements a phase control method for a quadrature modulator and a quadrature demodulator according to the present invention. FIG. 2 is a flowchart showing an example of a control procedure. Four
FIG. 3 is a block diagram showing an example of the configuration of a detector corresponding to the flowchart of FIG. 2. In FIG. 1, the same parts as those in FIG. 5 are designated by the same reference numerals. In addition, 8-1 and 8-2 are phase shifters, 10
Is a detector, 11 is a control device, 12 is a switcher, 16-1 is a 90 ° phase shifter composed of a 90 ° phase shifter 7-1 and a phase shifter 8-1, and 16-2 is a 90 ° phase shifter. The phase shift circuit composed of the multiplier 7-2 and the phase shifter 8-2, and 3'is composed of the multipliers 6-1, 6-2, the phase shift circuit 16-1, and the adder 9-1. The quadrature modulator 4'is a quadrature demodulator composed of multipliers 6-3 and 6-4 and a phase shift circuit 16-2. Also, in FIG. 4, 1-4 is an input terminal for the I component, 1-5 is an input terminal for the Q component, 2-
4 is the I component output terminal, 2-5 is the Q component output terminal, 15-1 and 15
Reference numeral -2 is a comparator, and 10 is a detector composed of the comparators 15-1 and 15-2. In the communication device of FIG. 1, on the transmitter side, the I component is input to the input terminal 1-1 and the Q component is input to the input terminal 1-2, and the multipliers 6-1 and 6-2 of the quadrature modulator 3 ′ are respectively input. To enter. The multiplier 6-1 multiplies the input I component by the separately input carrier and sends it to the adder 9, and the multiplier 6-2 multiplies the input Q component by the separately input carrier by way of the phase shift circuit 16-1. Adder
Send to 9. The adder 9 adds the two input multipliers and outputs the result from the output terminal 2-3 to a high frequency circuit such as a power amplifier. The quadrature modulator 3'outputs the carrier wave of the required frequency oscillated by the carrier wave oscillator 5 and inputs it to the multiplier 6-1 and the phase shift circuit 16-1. The carrier wave input to the phase shift circuit 16-1 is phase-shifted by 90 degrees by the 90-degree phase shifter 7-1 and further phase-shifted by the phase shifter 8-1 according to the control signal output from the controller 11 and output. Then, it is sent to the multiplier 6-2.

On the other hand, on the receiver side, a part of the signal output from the quadrature modulator 3'is fed back, and the demodulator input switch 12
Input to (terminal b of switch 12). Received signals from the received signal input terminals 1-3 are also input to the switch 12 (switch 1
The signal input to the terminal a) of 2 and the quadrature demodulator 4'is
It is selected by switching the input of the switch 12 according to the control information of one output. The quadrature demodulator 4 ′ inputs the output signal of the switching device 2 to the multiplier 6-3, and the multiplier 6-3 multiplies the input signal by the carrier wave input to the multiplier 6-3 separately to obtain the I component. It demodulates and outputs to the output terminal 2-1 and the detector 10. The output signal of the switching device 2 is also input to the multiplier 6-4, and the multiplier 6-4
Outputs the input signal to the output terminal 2-2 and the detector 10 by multiplying the input signal by the carrier wave sent separately via the phase shift circuit 16-2 to demodulate the Q component. The quadrature demodulator 4'includes a carrier oscillator 5
The carrier wave of a predetermined frequency oscillated by is sent and input to the multiplier 6-3 and the phase shift circuit 16-2. The carrier wave input to the phase shift circuit 16-2 is phase-shifted 90 degrees by the 90-degree phase shifter 7-2, and further phase-shifted by the phase shifter 8-2 according to the control signal of the controller 11 output. Then, it is sent to the multiplier 6-4.

The detector 10 detects a phase error based on the input amplitudes of the demodulated I component and the demodulated Q component, and outputs the detected error information to the controller 11. The controller 11 controls the phase shifter 8-1 of the quadrature modulator 3 ′, the phase shifter 8-2 of the quadrature demodulator 4 ′, and the switch 12 based on the input error signal. The phase shifter 8-1 corrects the phase error of the 90-degree phase shifter 7-1 by the control signal of the controller 11, and the phase shifter 8-2 receives the 90-degree phase shifter 7- by the control signal of the controller 11. Correct the phase error of 2. That is, the controller 11 cancels the phase error of the 90-degree phase shifter 7-1 of the quadrature modulator 3'and multiplies the I component and the Q component input from the input terminals 1-1 and 1-2, respectively. The quadrature demodulator 4'is controlled by controlling the phase shift amount of the phase shifter 8-1 so that the phase difference between the two carrier waves becomes exactly 90 degrees.
90 degree phase shifter 7-2 of the phase error is canceled, so that the phase difference between the two carrier waves multiplied by the input signal to output the I component and the Q component of the demodulated signal is exactly 90 degrees. The amount of phase shift of the phase shifter 8-2 is controlled, and while the phase control is being performed, the output signal of the quadrature modulator 3'is fed back to the demodulator input switch 12 to the quadrature demodulator 4 '. Input the switch 12 so that the input
Connect to the side.

Further, an example of the control means of the phase control method for the quadrature modulator and the quadrature demodulator will be described with reference to FIG. FIG. 2 is a flow chart for explaining the processing steps for performing the phase control of the quadrature modulator and the quadrature demodulator. At the start of control, the input of the switch 12 is set on the terminal b side so that the output signal branched from the quadrature modulator 3'is fed back to the quadrature demodulator 4'by the control of the controller 11 (feedback path connection Step 101). Next, in order to control the phase of the quadrature demodulator 4 ′, “A” (I = A, I = A,
A: positive constant), "0" (Q = 0) is input to the Q component input terminal 1-2, and a quadrature modulated wave subjected to quadrature modulation is output (I component signal input step 102). Quadrature demodulator 4'Q component output terminal 2
The amplitude of the signal of -2 is detected by the detector 10, and the phase shift amount φ of the phase shifter 8-2 is controlled by the controller 11 so that the amplitude of the Q component becomes “0” (φ after control: φ = φ = φ0 ) Is adjusted (demodulator phase shift control step 103). Next, to control the phase of the quadrature modulator 3 ',
Input "0" (I = 0) to the I component input terminal 1-1 of the quadrature modulator 3'and input "B" (Q = B, B: positive constant) to the Q component input terminal 1-2 for quadrature The modulated quadrature modulated wave is output (Q component signal input step 104). The detector 10 detects the amplitude of the I component output 2-1 of the quadrature demodulator 4 ', and the controller 11 controls the phase shift amount of the phase shifter 8-1 so that the amplitude of the I component becomes "0". θ (θ after control: θ = θ
0) (modulator phase control step 105). When the processing steps up to step 105 are completed, the phase correction of the quadrature modulator 3 ′ and the quadrature demodulator 4 ′ is completed, so the controller 11 receives the input of the quadrature demodulator 4 ′ from the input terminals 1-3 inputs. The switch 12 input is connected to the terminal a side so that it becomes a signal (return path disconnection step 106). Through the above process, the phase of the communication device is adjusted.

Detector 10 for performing the control procedure described above
An example of this is shown in FIG. FIG. 4 is a block diagram showing the configuration of a detector used when executing the phase control of the present invention. 1-4 is I component input terminal, 1-5 is Q component input terminal, 15-1
And 15-2 are comparators, 10 is a detector composed of comparators 15-1 and 15-2, and 2-4 and 2-5 are output terminals. In FIG. 4, the I component input terminal 1-4 and the Q component input terminal 1-5 are input to one input of the comparators 15-1 and 15-2. “0” is input to the other input of each of the two comparators, and the two are compared and the judgment result of the sign of the input signal is output (for example, if the input signal is> 0, the comparator output is 1). , If the input signal ≤ 0, the comparator output = 0). The outputs of the comparators 15-1 and 15-2 are output from the output terminals 2-4 and 2-5 to the controller 11. In the demodulator phase control step 103 of FIG. 2 described above, the code of the demodulated Q component input to the input terminal 1-5 is determined by the comparator 15-2, and the controller 11 determines the code of the output of the comparator 15-2. While observing the change, the phase shift amount φ of the phase shifter 8-2 is varied to determine the phase shift amount φ0 immediately before the sign change. In the modulator phase control step 105 of FIG. 2, the sign of the demodulated I component input to the input terminal 1-4 is determined by the comparator 15-1, and the controller 11 determines the sign of the output of the comparator 15-1. The phase shift amount θ of the phase shifter 8-1 is varied while observing the change, and the phase shift amount θ0 immediately before the sign change is determined.

With the above phase control procedure, the quadrature demodulator
Quadrature modulator 3'and quadrature demodulator by detecting only 4'output
Calibrate the 4'phase error. The phase shift circuit 16-1 of the quadrature modulator 3'and the phase shift circuit 16-2 of the quadrature demodulator 4'include a 90-degree phase shifter 7-1 or 7-2 and a phase shifter 8-1 or 8- Although it is composed of two circuits of 2 respectively, the 90-degree phase shifter is omitted and only the phase shifters 8-1 and 8-2 are used. It is also possible to correct the phase error of 8-2 (however, the initial values of the phase shifters 8-1 and 8-2 are 90 degrees).
Further, in the above control procedure and an example of the detector, since the code of the demodulated signal is detected and the phase control is performed, when there is an amplitude deviation between the I component and the Q component of the quadrature modulator 3 ′, or , Even if there is an amplitude deviation between the I component and the Q component of the quadrature demodulator 4 ′, the phase control of the quadrature modulator 3 ′ and the quadrature demodulator 4 ′ can be performed without being affected by these amplitude deviations. It can be carried out. Further, by performing the above-mentioned phase control at the time of turning on the power of the communication device, immediately before performing communication, or intermittently during non-communication, it is possible to calibrate the secular change and the temperature change of the phase error. Communication can be performed without deterioration of the modulation accuracy of the quadrature modulator and the demodulation accuracy of the quadrature demodulator.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block configuration diagram of a communication device having a transmission unit that feeds back a part of the transmission output to compensate for the non-linear distortion of the power amplifier. How the phase control of the quadrature modulator and the quadrature demodulator is performed on the communication device of FIG. 3 will be described. 1-1 is the input terminal for the I component of the baseband signal, 1-2 is the input terminal for the Q component of the baseband signal, 9-1 and 9
-2 is an adder, 5 is a carrier oscillator, 3'quadrature modulator, 4'quadrature demodulator, 13 is a power amplifier, 14 is a directional coupler, 2-6 is an output terminal, 10 is a detector, 11 is control It is a device. In FIG. 3, the I component signal is input to the input terminal 1-1 and the Q component signal is input to the input terminal 1-2, and are input to the adders 9-1 and 9-2, respectively. In the adder 9-1, the demodulation I separately sent from the orthogonal demodulator 4 '
The component and the I component from the input terminal 1-1 are added and input to the quadrature modulator 3 '. Similarly, in the adder 9-1, the demodulation Q component separately sent from the quadrature demodulator 4'and the Q component from the input terminal 1-2 are added and input to the quadrature modulator 3 '. The quadrature modulator 3 ′ quadrature-modulates the input I-component and Q-component signals based on the carrier wave input from the carrier wave oscillator 5, and outputs them to the power amplifier 13. After being amplified to the power level to be transmitted by the power amplifier 13, the output terminal 1-6 outputs the signal via a high frequency circuit such as an antenna.

Further, a part of the signal output of the power amplifier 13 is
It is fed back through the directional coupler 14 and input to the quadrature demodulator 4 '. The quadrature demodulator 4 ′ quadrature demodulates the partial output signal fed back from the power amplifier 13 based on the carrier wave input from the carrier wave oscillator 5. The output signal of the I component of the quadrature demodulator 4'is input to the adder 9-1, the output signal of the Q component is input to the adder 9-2, and the I signal from the input terminals 1-1 and 1-2 is input. Since the component signal and the Q component signal are respectively negatively fed back, the non-linear distortion of the power amplifier is compensated.

In FIG. 3, a control signal is output from the control device 11 and sent to the adders 9-1 and 9-1, and the feedback signals from the quadrature demodulator 4'are added in the adders 9-1 and 9-1. By controlling so as not to be input (or not input), the same operation as that of the switch 12 of FIG. 1 is performed, and the phase control described in FIG. 1 or 2 is executed by the quadrature modulator 3 ′ and the quadrature demodulator 4 ′. Thereby, the phase control of the present invention can be implemented. That is, the quadrature modulator 3'which controls the phase of the carrier on the Q phase side by the control signal of the controller 11 output, and the Q by the control information of the controller 11 output.
The quadrature demodulator 4'for controlling the phase of the carrier wave on the phase side, the detector 10 for detecting the phase error by inputting the signal of the quadrature demodulator 4 ', and the error signal of the output of the detector 10 are input. Phase control information of quadrature modulator 3'and quadrature modulator 4'and adder
The phase control can be executed according to the control procedure of FIG. 2 by using the controller 11 for controlling 9-1 and 9-2 (however, the I component signal input step 102 and the feedback path disconnection step 106 of FIG. 2 are performed. Instead of the return path switching control in
Here, the adders 9-1 and 9-2 are controlled).

[0021]

As described above, according to the present invention, in a communication device including a quadrature modulator and a quadrature demodulator, a quadrature modulator and a quadrature demodulator from a signal of a demodulation I component and a demodulation Q component of a quadrature demodulator output. The phase difference between the two carriers in the quadrature modulator and the quadrature demodulator is detected by detecting the phase error of the signal and performing phase control based on the error signal with the phase shifter provided in the quadrature modulator and the phase shifter provided in the quadrature demodulator. Can be controlled to be 90 degrees to improve the deterioration of the received data error rate.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a communication device of the present invention.

FIG. 2 is a flowchart showing an embodiment of the control means of the present invention.

FIG. 3 is a block diagram showing the configuration of another embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a detector according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional communication device.

FIG. 6 is a diagram for explaining deterioration of modulation accuracy due to a phase error.

[Explanation of symbols]

1-1, 1-2, 1-3, 1-4, 1-5: Input terminal, 2-1, 2-2, 2-
3, 2-4, 2-5, 2-6: Output terminal, 3, 3 ': Quadrature modulator,
4, 4 ': Quadrature demodulator, 5: Carrier wave oscillator, 6-1, 6-
2, 6-3, 6-4: Multiplier, 7-1, 7-2: 90 degree phase shifter, 8-
1, 8-2: Phase shifter, 9, 9-1, 9-2: Adder, 10: Detector, 11: Control device, 12: Switching device, 13: Power amplifier, 14: Directional coupler, 15-1, 15-2: Comparator, 16
-1, 16-2: Phase shift circuit,

Claims (3)

(57) [Claims] 1. A communication device for performing digital signal processing, comprising a quadrature modulator and a quadrature demodulator, wherein a carrier wave oscillating means outputs a carrier wave of a required frequency, and the carrier wave of the required frequency is the quadrature modulator. Entered in
First phase shifting means for adjusting a phase difference between a first carrier wave multiplied by the I component side signal and a second carrier wave multiplied by the Q component side by a control signal; and a quadrature demodulated signal from the quadrature demodulator. Before to output
The carrier of the required frequency is input to the quadrature demodulator,
Second phase shifting means for adjusting a phase difference between a third carrier wave multiplied by the I component side signal and a fourth carrier wave multiplied by the Q component side by a control signal, and an I component outputted from the quadrature demodulator And a detector that detects a phase error from the signal of the Q component and outputs error information, and controls the first phase shift means and the second phase shift means based on the error information output from the detector. Control means for outputting a signal to control the phase of the carrier wave, and multiplying the quadrature modulator from the phase error signal detected from the I component and Q component signals of the quadrature demodulator output by the control means. Controlling the first phase shifting means so that the phase difference of the carrier waves becomes 90 degrees, and controlling the second phase shifting means so that the phase difference of the carrier waves multiplied by the quadrature demodulator becomes 90 degrees , Input I of the signal input to the quadrature modulator Minute and the input Q formed
Input a signal with a predetermined amplitude to one side and zero amplitude to the other side
Then, the second phase shifting means is controlled, and the input I component and the input Q input to the quadrature modulator are controlled.
When controlling the second phase shifting means for the component signal
Given a predetermined amplitude to the input component whose amplitude is zero,
When controlling the phase shifting means of No. 2, the input signal with a given amplitude is applied.
By setting the minute amplitude to zero, the first transfer partner
A phase control method for a quadrature modulator and a quadrature demodulator, which is characterized by performing stage control . 2. A quadrature modulator for performing digital signal processing,
In a communication device having a quadrature demodulator, a part of the output signal of the quadrature modulator is fed back as a feedback signal.
Means for demodulating in the quadrature demodulator with the feedback signal
Input the demodulation input signal of the
Before switching either of the force signals by the control means
The switching means for outputting to the quadrature demodulator and the required frequency
A carrier wave oscillating means for outputting a transmission wave, wherein the control means inputs a carrier wave of the required frequency to the quadrature modulator,
Do not multiply the first carrier wave multiplied by the I component side signal and the Q component side
The phase difference between the second carrier and the second carrier is adjusted by the control signal.
First phase shifting means for outputting a quadrature demodulated signal from the quadrature demodulator,
The carrier of the required frequency is input to the quadrature demodulator,
The third carrier multiplied by the signal on the I component side and the third carrier on the Q component side
The phase difference between the fourth carrier and the
From the second phase shifting means and the I and Q component signals output from the quadrature demodulator,
A detector that detects a phase error and outputs error information; and the detector based on the error information output from the detector .
The control signal is output to the first phase shift means and the second phase shift means.
And a control means for controlling the phase of the carrier wave by applying the input signal to the quadrature demodulator output by the control means.
From the phase error signal detected from the minute and Q component signals,
The phase difference of the carrier wave multiplied by the quadrature modulator should be 90 degrees.
To control the first phase shifting means and not to multiply the quadrature demodulator
The second phase shift so that the phase difference between the carrier waves becomes 90 degrees.
Means for controlling the input I component and the input Q component of the signal input to the quadrature modulator.
Input a signal with a predetermined amplitude to one side and zero amplitude to the other side
Then, the second phase shifting means is controlled, and the input I component and the input Q input to the quadrature modulator are controlled.
When controlling the second phase shifting means for the component signal
Given a predetermined amplitude to the input component whose amplitude is zero,
When controlling the phase shifting means of No. 2, the input signal with a given amplitude is applied.
By setting the minute amplitude to zero, the first transfer partner
Quadrature modulator and quadrature demodulation characterized by performing stage control
Device equipped with an instrument. 3. A quadrature modulator for digital signal processing
In a communication device including a quadrature demodulator, a part of the output of the power amplifier is fed back to the quadrature modulator.
The power amplifier to detect the nonlinear distortion of the power amplifier.
And a transmitter that compensates for the non-linear distortion of the power amplifier.
And carrier wave oscillating means for outputting a carrier wave of a desired frequency
When, a phase control means for inputting the output of the quadrature demodulator, the phase control means, the carrier of the required frequency is input to the quadrature modulator,
Do not multiply the first carrier wave multiplied by the I component side signal and the Q component side
The phase difference between the second carrier and the second carrier is adjusted by the control signal.
First phase shifting means for outputting a quadrature demodulated signal from the quadrature demodulator,
The carrier of the required frequency is input to the quadrature demodulator,
The third carrier multiplied by the signal on the I component side and the third carrier on the Q component side
The phase difference between the fourth carrier and the
From the second phase shifting means and the I and Q component signals output from the quadrature demodulator,
A detector that detects a phase error and outputs error information; and the detector based on the error information output from the detector .
The control signal is output to the first phase shift means and the second phase shift means.
And a control means for controlling the phase of the carrier wave by applying the input signal to the quadrature demodulator output by the control means.
From the phase error signal detected from the minute and Q component signals,
The phase difference of the carrier wave multiplied by the quadrature modulator should be 90 degrees.
To control the first phase shifting means and not to multiply the quadrature demodulator
The second phase shift so that the phase difference between the carrier waves becomes 90 degrees.
Means for controlling the input I component and the input Q component of the signal input to the quadrature modulator.
Input a signal with a predetermined amplitude to one side and zero amplitude to the other side
Then, the second phase shifting means is controlled, and the input I component and the input Q input to the quadrature modulator are controlled.
When controlling the second phase shifting means for the component signal
Given a predetermined amplitude to the input component whose amplitude is zero,
When controlling the phase shifting means of No. 2, the input signal with a given amplitude is applied.
By setting the minute amplitude to zero, the first transfer partner
Quadrature modulator and quadrature demodulation characterized by performing stage control
And a communication device.