JP4533759B2 - Data converter, data conversion method, and transmission circuit, communication device, and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter circuit in which quantization noise is suppressed and power consumption can be reduced, and to provide a data converter and data conversion method used therefor, and communication device using the same. <P>SOLUTION: The data converter for converting an input signal to a signal to be input to an amplifier includes: an amplitude detection section for detecting an amplitude level of the input signal; a region determination section for determining whether or not an input power to the amplifier is in a non-linear region of the amplifier on the basis of the amplitude level of the input signal detected by the amplitude detection section; and a signal processing section for converting the input signal to a signal having a lower resolution than that of the input signal if the region determination section determines that the input power to the amplifier is in the non-linear region of the amplifier. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a transmission circuit used in a communication device such as a mobile phone and a wireless LAN, an electronic device such as an audio device and a video device, a data converter used in the electronic device, and a data conversion method. The present invention relates to a transmission circuit capable of suppressing noise, a communication device, an electronic device, a data converter used in them, and a data conversion method.

FIG. 28 is a block diagram showing a configuration of a conventional communication device 900. In FIG. 28, a conventional communication device 900 includes a transmission circuit 901, a reception circuit 902, an antenna duplexer 903, and an antenna 904. The high-frequency transmission signal generated by the transmission circuit 901 is radiated from the antenna 904 to the space via the antenna duplexer 903. On the other hand, the high-frequency signal received by the antenna 904 is sent to the reception circuit 902 via the antenna duplexer 903 and is subjected to reception processing. As the antenna duplexer 903, for example, a duplexer using a switch, a dielectric, a SAW (Surface Acoustic Wave) filter, an FBAR (Film Bulk Acoustic Resonator) filter, or the like is used.

  FIG. 29 is a block diagram showing an example of the configuration of the transmission circuit 901 in the conventional communication device 900 shown in FIG. FIG. 29 schematically shows waveforms in the main part. The transmission circuit 901 is a transmission circuit that generates a transmission signal by polar modulation. In FIG. 29, the conventional transmission circuit 901 includes a data generation unit 910, an angle modulator 920, and an amplitude modulator 930.

  The data generation unit 910 converts an orthogonal coordinate system baseband signal represented by I data (in-phase data) and Q data (quadture-phase data) into orthogonal polar systems, Output phase data. The amplitude data is input to the amplitude modulator 930. The phase data is input to the angle modulator 920.

  The angle modulator 920 angle-modulates input phase data and outputs a carrier wave. The output carrier wave is input to the amplitude modulator 930.

  The amplitude modulator 930 modulates and outputs the carrier wave from the angle modulator 920 with the amplitude data from the data generation unit 910. Thereby, a transmission signal is obtained. Such a modulation method is called polar modulation.

  FIG. 30 is a block diagram showing a configuration of the amplitude modulator 930. 30, the amplitude modulator 930 includes matching circuits 931 and 936, a transistor 932, a DC power supply 933, and bias circuits 934 and 935.

  The angle modulation wave output from the angle modulator 920 is amplified by the transistor 932 via the matching circuit 931 and output via the matching circuit 936. The matching circuits 931 and 936 are circuits for matching between the input and output of the transistor 932. The bias circuits 934 and 935 are circuits for supplying a bias voltage to the base, gate, collector, or drain of the transistor, respectively. A DC voltage is supplied to the base terminal of the transistor 932 from the DC power supply 933 via the bias circuit 934. The gain of the transistor 932 changes in accordance with the voltage supplied from the data generation unit 910. That is, amplitude modulation is realized by supplying a voltage proportional to the amplitude data output from the data generation unit 910 to the transistor 932.

  However, the transmission circuit 901 shown in FIG. 29 has a problem that the output signal is distorted when, for example, the input power to the transistor 932 becomes high or low. FIG. 31 is an example of a schematic diagram for explaining the cause of this distortion.

  In FIG. 31, the horizontal axis indicates the magnitude of input power to the transistor 932, that is, the magnitude of amplitude data. The left vertical axis indicates the magnitude of the output power of the transistor 932. The right vertical axis indicates the phase of a signal passing through the transistor 932 (hereinafter referred to as a passing phase).

  In FIG. 31, the output power and the passing phase are displayed together. Therefore, it is necessary to indicate which characteristic is indicated by the line indicating the characteristic on the graph. In FIG. 31, which characteristic is shown is represented using an ellipse frame with an arrow. The characteristic of the line surrounded by the ellipse frame is the vertical axis indicated by the arrow attached to the ellipse frame.

  In an ideal transistor, input power and output power are in a proportional relationship. In an ideal transistor, the passing phase is kept constant even when the input power increases. In FIG. 31, this ideal transistor characteristic is indicated by a dotted line on the high input power side. Thus, in an ideal transistor, the output power and the passing phase change linearly at all input powers.

  However, actual transistors are not necessarily linear at all input powers. As shown in FIG. 31, when the input power is larger than P, the output power and the input power are not in a proportional relationship, and the passing phase is not constant. That is, when the input power is greater than P, the transistor characteristics are non-linear.

  When amplitude data is input to such a non-linear region, the output power is amplified without being proportional, and the phase is shifted. That is, when amplitude data is input to the nonlinear region, the output signal is distorted. That is, when the output of the transmission circuit is high, the output signal is distorted.

  Conventionally, methods for discretizing amplitude data have been proposed in order to solve such problems. FIG. 32 is a block diagram showing another configuration example of the transmission circuit in the conventional communication device 900 shown in FIG. 28 (see Patent Document 1). In FIG. 32, the transmission circuit 901a includes a data generation unit 910, an angle modulator 920, an amplitude modulator 930, a bandpass filter 940, and a delta-sigma modulator 950. In FIG. 32, the same reference numerals are assigned to the same parts as in FIG. In FIG. 32, the waveform of the main part is schematically shown.

  In the transmission circuit 901a, the amplitude data output from the data generation unit 910 is delta-sigma-modulated in the delta-sigma modulator 950 and discretized into a binary signal (typically binary of 0 and a positive real number). And input to the amplitude modulator 930.

  On the other hand, the phase data output from the data generation unit 910 is input to the angle modulator 920, angle-modulated, output as an angle-modulated wave, and input to the amplitude modulator 930.

  The amplitude modulator 930 amplitude-modulates the carrier wave from the angle modulator 920 with the signal from the delta-sigma modulator 950. The configuration of the amplitude modulator 930 is the same as that shown in FIG. Therefore, when a voltage corresponding to the binary signal output from the delta-sigma modulator 950 is supplied to the transistor 932, the carrier wave is turned on / off by the binary signal, and amplitude modulation is realized.

  The bandpass filter 940 removes quantization noise generated by delta-sigma modulation and outputs a transmission signal.

In this way, the transmission circuit 901a performs amplitude modulation using the binary signal that has been subjected to delta-sigma modulation, and therefore, the angle modulation wave of the signal output from the amplitude modulator 930 is only turned on / off. Therefore, the output signal from the transmission circuit 901a is not distorted.
Japanese Patent Laid-Open No. 2002-325109, FIG.

  However, the transmission circuit 901a shown in FIG. 32 has a problem that a lot of quantization noise is included. FIG. 33 is a diagram showing an output spectrum from the amplitude modulator 930 of the transmission circuit 901a shown in FIG. FIG. 34 is a diagram showing an output spectrum from the bandpass filter 940 of the transmission circuit 901a shown in FIG. The zero point of the frequency on the horizontal axis represents the center frequency.

  As shown in FIG. 33, the output from the amplitude modulator 930 contains a lot of quantization noise. Therefore, the quantization noise needs to be removed by the band pass filter 940, but removing the quantization noise results in a loss. For example, if the quantization noise energy accounts for 30 to 40% of the total energy, even if the efficiency of the amplitude modulator 930 is set to 100%, the total efficiency of the transmission circuit 901a is reduced from 60 to 70%. End up. Therefore, the power consumption of the entire transmission circuit cannot be reduced unless the quantization noise power is reduced. That is, if the quantization noise power is large, the power consumption of the entire transmission circuit also increases.

  Furthermore, a large amount of suppression is required for the bandpass filter 940 in order to sufficiently remove unnecessary quantization noise. In order to realize this, the passage loss in the bandpass filter 940 increases. In addition, in order to obtain a large amount of suppression, the configuration of the bandpass filter 940 increases, and as a result, the circuit scale of the entire transmission circuit also increases.

  Also, as shown in FIG. 34, the quantization noise near the desired wave frequency cannot be removed by the bandpass filter. Therefore, in order to remove the quantization noise near the desired wave frequency, the delta sigma modulator 950 needs to have sufficiently low noise. In order to realize this, the clock frequency of the delta-sigma modulator 950 must be increased to reduce the quantization noise near the desired wave frequency. However, this leads to an increase in power consumption in the delta sigma modulator 950.

  Therefore, an object of the present invention is to provide a transmission circuit, a communication device, an electronic device, a data converter used in them, and a data conversion method that can suppress quantization noise and reduce power consumption. That is.

  In order to solve the above problems, the present invention has the following features. The present invention relates to a data converter for converting an input signal into a signal for input to an amplifier and outputting the signal, an amplitude detector for detecting the amplitude of the input signal, and an input detected by the amplitude detector Based on the amplitude of the signal, a region determination unit that determines whether or not the input power to the amplifier belongs to the nonlinear region of the amplifier, and the region determination unit causes the input power to the amplifier to belong to the nonlinear region of the amplifier A signal processing unit that converts the input signal into a signal having a lower resolution than the input signal and outputs the converted signal.

  For example, when the input signal is discretized, the signal processing unit may convert the input signal into a signal having a resolution lower than that of the input signal by widening the interval between the discrete values.

  For example, when the input signal is not discretized, the signal processing unit may convert the input signal into a signal having a resolution lower than that of the input signal by discretizing the input signal.

  Further, for example, the signal processing unit further determines that the input power to the amplifier does not belong to the non-linear region of the amplifier when the region determining unit determines that the input power does not belong to the non-linear region of the amplifier. The input signal may be discretized so that the interval between the discrete values becomes narrow.

  Preferably, when the input signal is orthogonal data, the amplitude detection unit may detect the magnitude of the amplitude of the input signal by obtaining the square root of these square sums.

  Preferably, a correction unit that corrects the signal after conversion by the signal processing unit so that distortion generated in the amplifier is suppressed may be further provided.

  For example, the correction unit may correct the amplitude and phase of the input signal.

  Further, for example, the correction unit may generate a signal having an equal amplitude opposite phase with respect to the distortion generated in the amplifier.

  For example, the region determination unit may determine that the input voltage to the amplifier belongs to the nonlinear region when the magnitude of the amplitude of the input signal exceeds the first threshold.

  In addition, for example, the region determination unit may determine that the input signal belongs to the nonlinear region when the amplitude of the input signal does not exceed the second threshold value.

  In addition, for example, the region determination unit may determine that the input signal belongs to the nonlinear region when the amplitude of the input signal does not exceed the third threshold value or exceeds the fourth threshold value.

  For example, the signal processing unit may convert the input signal into a signal having a resolution lower than that of the input signal by delta-sigma modulation.

  Preferably, the amplifier receives the signal amplified by the variable gain amplifier, and the region determination unit inputs the signal to the amplifier based on whether the amplitude of the input signal is out of the set range. A setting range adjustment unit may be provided that determines whether the voltage belongs to the nonlinear region of the amplifier and further adjusts the setting range based on information indicating the gain of the variable gain amplifier.

  Further, for example, the signal processing unit includes a coordinate system conversion unit that converts an input signal into amplitude data and phase data, a delta sigma modulator that performs delta sigma modulation on the amplitude data converted by the coordinate system conversion unit, and phase data A multiplier may be included that multiplies the amplitude data that has been delta-sigma modulated by the delta-sigma modulator.

  Also, for example, the input signal is orthogonal data, and the signal processing unit is connected to a subtractor to which the input signal is input, a vector integrator that is connected to the subtractor and integrates each element of the orthogonal data, and vector integration Using the at least two or more discrete values for the orthogonal data integrated by the device, the maximum discrete value smaller than the vector size of the input orthogonal data is obtained from the two or more discrete values, A vector quantum that quantizes so that the magnitude of the vector of the integrated orthogonal data becomes the maximum discrete value and the phase of the integrated orthogonal data is equal to the phase of the input orthogonal data The subtractor may subtract the orthogonal data quantized by the vector quantizer from the input orthogonal data.

  Further, the present invention is a transmission circuit for generating a transmission signal, and includes an amplifier and a data converter that converts an input signal into a signal used as an input of the amplifier, and the data converter An amplitude detector that detects the magnitude of the amplitude, and a region determination that determines whether or not the input power to the amplifier belongs to the nonlinear region of the amplifier based on the amplitude of the input signal detected by the amplitude detector And a signal processing unit that converts the input signal into a signal having a resolution lower than that of the input signal and outputs the signal when the input power to the amplifier belongs to the nonlinear region of the amplifier.

  Preferably, a correction unit that corrects the signal after conversion by the signal processing unit so that distortion generated in the amplifier is suppressed may be further provided.

  Preferably, a filter connected after the amplifier is further provided.

  The preferred embodiment further includes a variable gain amplifier that adjusts the power of the signal input to the amplifier, and the region determination unit is configured to determine whether the amplitude of the input signal is outside a predetermined setting range. Then, it is determined whether or not the input power to the amplifier belongs to the non-linear region, and the data converter further includes a setting range adjustment unit that adjusts the setting range based on information indicating the gain of the variable gain amplifier.

  In a preferred embodiment, the input signal to the data converter is orthogonal data, the data converter outputs the converted orthogonal data, and further modulates the converted orthogonal data output by the data converter. The amplitude detector detects the magnitude of the amplitude of the input signal based on the orthogonal data.

  In a preferred embodiment, the input signal to the data converter is orthogonal data, the data converter outputs the converted orthogonal data, and further converts the converted orthogonal data into polar coordinate system data, A coordinate system conversion unit that generates amplitude data and phase data, and an angle modulator that angle-modulates the phase data generated by the coordinate system conversion unit. The amplifier coordinates the phase data angle-modulated by the angle modulator. The amplitude modulator performs amplitude modulation based on the amplitude data generated by the system conversion unit, and the amplitude detection unit detects the magnitude of the amplitude of the input signal based on the orthogonal data.

  In a preferred embodiment, the data conversion section further includes a data generation section that generates amplitude data and phase data, and an angle modulator that angle-modulates the phase data generated by the data generation section to generate an angle-modulated wave. The input signal to the detector is the amplitude data generated by the data generation unit, the data converter outputs the converted amplitude data, and the amplitude detection unit is based on the amplitude data, the magnitude of the amplitude of the input signal The amplifier is an amplitude modulator that modulates the amplitude of the phase data angle-modulated by the angle modulator based on the amplitude data converted by the data converter. Based on this, the magnitude of the amplitude of the input signal is detected.

  The present invention is a communication device including a transmission circuit for generating a transmission signal and a reception circuit for processing the reception signal. The transmission circuit is used as an amplifier and an input signal as an input of the amplifier. A data converter that converts the signal into a signal, the data converter including an amplitude detector that detects the amplitude of the input signal, and an amplifier based on the amplitude of the input signal detected by the amplitude detector When the region determination unit determines whether the input power to the amplifier belongs to the nonlinear region of the amplifier, the region determination unit that determines whether the input power to the amplifier belongs to the nonlinear region of the amplifier A signal processing unit that converts an input signal into a low signal and outputs the converted signal.

  The present invention is an electronic device, and includes an amplifier and a data converter that converts an input signal into a signal to be input to the amplifier and outputs the signal, and the data converter detects the magnitude of the amplitude of the input signal. An amplitude detection unit that determines whether or not the input power to the amplifier belongs to the nonlinear region of the amplifier based on the magnitude of the amplitude of the input signal detected by the amplitude detection unit, and a region determination unit The signal processing unit converts the input signal into a signal having a resolution lower than that of the input signal and outputs the signal when the input power to the amplifier belongs to the nonlinear region of the amplifier.

  The present invention relates to a processing method in a data converter for converting an input signal into a signal for input to an amplifier, the step of detecting the magnitude of the amplitude of the input signal, and the magnitude of the detected amplitude of the input signal. And determining whether the input power to the amplifier belongs to the nonlinear region of the amplifier, and if the input power to the amplifier belongs to the nonlinear region of the amplifier, the resolution is higher than the input signal. Converting the input signal into a low signal and outputting the signal.

  Preferably, in the step of determining whether or not it belongs to the nonlinear region of the amplifier, the input power to the amplifier belongs to the nonlinear region of the amplifier based on whether or not the magnitude of the amplitude of the input signal is outside the setting range. It is preferable to further comprise a step of adjusting the setting range based on information indicating the gain of the variable gain amplifier connected to the previous stage of the amplifier.

  Hereinafter, the effects of the present invention will be described. In the present invention, by detecting the magnitude of the amplitude of the input signal, based on the detected magnitude of the amplitude of the input signal, it is determined whether or not the input power to the amplifier belongs to the nonlinear region of the amplifier, When belonging to the non-linear region, the resolution of the input signal is lowered and output. Therefore, only the portion of the input signal corresponding to the nonlinear region of the amplifier is discretized. Therefore, since only a part of the input signal is discretized, the quantization noise is reduced as compared with the conventional case where all of the input signal is discretized.

  By reducing the quantization noise, it is not necessary to amplify an unnecessary signal with an amplifier, so that the power consumption of the entire transmission circuit can be reduced.

  Further, since the power and phase of the discretized input signal and the power and phase of the output signal corresponding to the discretized input signal are corrected by the correction unit, distortion in the amplifier does not occur. .

  Further, since the quantization noise is suppressed as a whole, the quantization noise near the desired wave frequency is also suppressed. Therefore, the attenuation characteristic required for the bandpass filter in the transmission circuit is relaxed, and as a result, the passage loss is reduced. Further, it is not necessary to use a steep band pass filter, which leads to a reduction in power consumption of the transmission circuit. As a result, the entire transmission circuit can be reduced in size.

  In this embodiment, since the resolution of the amplitude is small, the table is extremely small as compared with a case where a compensation table is prepared in a conventional transmission circuit that does not perform data conversion by the delta-sigma modulator.

  In general, there are cases where the clock frequency for discretization in the data converter is increased to reduce the quantization noise near the desired wave frequency, but in the present invention, the quantization noise has already been reduced, Since it is not necessary to increase the clock frequency of the data converter, the power consumption of the data converter is reduced.

  When the input signal is discretized, the signal processing unit can obtain a signal having a resolution lower than that of the input signal by widening the interval between the discrete values, and thus the processing is simple.

  When the input signal is not discretized, the signal processing unit can obtain a signal having a resolution lower than that of the input signal by discretizing the input signal. Therefore, a general discretization method such as delta-sigma modulation is used. A signal having a resolution lower than that of the input signal can be obtained only by using.

  The signal processing unit further determines that the input power to the amplifier does not belong to the nonlinear region of the amplifier when the region determination unit determines that the input power to the amplifier does not belong to the nonlinear region, compared to the case where the discrete value is discretized. By discretizing the input signal so that the interval is narrowed, a signal having a resolution lower than that of the input signal can be obtained.

  When the input signal is orthogonal data, the amplitude detector detects the magnitude of the amplitude of the input signal by obtaining the square root of these sums of squares. Therefore, the magnitude of the amplitude of the input signal can be easily detected. Can do.

  The region determination unit can easily determine whether or not the input power to the amplifier belongs to the nonlinear region by using any of the first to fourth threshold values.

  Since the setting range adjustment unit adjusts the setting range based on the information indicating the gain of the variable gain amplifier, whether or not to change the input signal to a signal with low resolution according to the power actually input to the amplifier. Will be judged.

  By using a delta-sigma modulator or a vector quantizer for the signal processing unit, a part of the input signal can be a signal with low resolution.

  The transmission circuit, communication device, and electronic device including the data converter of the present invention can suppress quantization noise and reduce power consumption.

  These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Since the communication apparatus to which the transmission circuit of the present invention is applied is the same as the conventional one, FIG. 28 is also used in the following embodiments. In the following embodiments, description will be made mainly on the case where the data converter of the present invention is applied to a communication device. However, the data converter of the present invention is not only a communication device but also an amplifier such as an audio device or a video device. It can be applied to all electronic devices equipped with.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a transmission circuit 100 according to the first embodiment of the present invention. In FIG. 1, a transmission circuit 100 includes an input terminal 101, a data converter 110, a correction unit 120, a compensation table unit 130, a vector modulator 140, a variable gain amplifier 150, an amplifier 160, a bandpass filter. 170 and an output terminal 102.

  The transmission circuit 100 receives I data and Q data which are orthogonal data from a data generation unit (not shown). The transmission circuit 100 converts the input I data and Q data into a high-frequency transmission signal and outputs it.

  A data generation unit (not shown) is connected to one end of the input terminal 101. The data converter 110 is connected to the other end of the input terminal. A correction unit 120 is connected to the output side of the data converter 110. The compensation table unit 130 is connected to the correction unit 120. A vector modulator 140 is connected to the output side of the correction unit 120. A variable gain amplifier 150 is connected to the output side of the vector modulator 140. An amplifier 160 is connected to the output side of the variable gain amplifier 150. A band pass filter 170 is connected to the output side of the amplifier 160. The output terminal 102 is connected to the output side of the band pass filter 170.

  The data converter 110 converts a signal input to the input terminal 101 into a signal to be input to the amplifier 160. The correction unit 120 corrects the data value (amplitude value and phase value) of the signal output from the data converter 110. The compensation table unit 130 is a storage unit that stores a compensation table that is referred to when the correction unit 120 performs correction. Since the data converter 110, the correction unit 120, and the compensation table unit 130 are devices for converting an input signal into a signal for input to the amplifier 160, they can be collectively referred to as a data converter. .

  The vector modulator 140 is a modulator for modulating orthogonal data so that it is on a carrier wave. The variable gain amplifier 150 makes the gain variable and adjusts the power to be input to the amplifier 160 in accordance with an instruction from an external control unit (not shown). The amplifier 160 is composed of a transistor, and amplifies and outputs an input signal. The band pass filter is a filter for passing a signal in a desired frequency band.

  Hereinafter, the operation of the transmission circuit 100 will be described.

An input signal to the data converter 110 is orthogonal data indicated by I data and Q data. The data converter 110 detects (I ² + Q ² ) ^1/2 that is the magnitude of the amplitude of the orthogonal data that is the input signal, based on the I data and the Q data input to the input terminal 101. The data converter 110 determines whether or not the detected amplitude magnitude (I ² + Q ² ) ^1/2 is within a set range. The data converter 110 changes the setting range in accordance with the magnitude of power to be output from the amplifier 160 transmitted from an external control unit (not shown).

  If the size is within the set range, the data converter 110 outputs I data and Q data as they are. On the other hand, when the size is not within the set range, the data converter 110 lowers the resolution of the vector size formed by the input I data and Q data, and outputs it as I2 data and Q2 data. In the present specification, the size of orthogonal data means the size of a vector formed by orthogonal data. Specifically, when the orthogonal data is discretized in advance, the data converter 110 reduces the resolution by widening the interval between the discrete values if the size is not within the set range. On the other hand, when the orthogonal data is not previously discretized, the data converter 110 reduces the resolution by discretizing the magnitude of the input signal if the magnitude is not within the set range. In this way, the data converter converts an input signal having an amplitude value outside the set range into a signal having a resolution lower than that of the amplitude, and outputs the signal.

  In the compensation table of the compensation table unit 130, information for correcting the amplitude value and the phase value of the amplitude signal based on the I2 data and the Q2 data is defined.

  When the data input from the data converter 110 is I2 data and Q2 data, the correction unit 120 refers to the compensation table stored in the compensation table unit 130 and determines the amplitude value obtained from the I2 data and Q2 data. And the phase value are corrected and output as I3 data and Q3 data. On the other hand, when the data input from data converter 110 is I data and Q data, correction unit 120 outputs I data and Q data as they are.

  The vector modulator 140 combines the input orthogonal data and the carrier wave, and modulates the orthogonal data so as to ride on the carrier wave.

  For example, the vector modulator 140 is a quadrature modulator. In this case, the vector modulator 140 converts the input I data (or I3 data) and Q data (or Q3 data) into Icos (ωt) −Qsin (ωt) or I3cos (ωt) −Q3sin (ωt). Convert and output. Here, it is assumed that I, Q, I3, and Q3 indicate values of I data, Q data, I3 data, and Q3 data (the same applies hereinafter).

Further, for example, the vector modulator 140 may be a polar modulator. In this case, the vector modulator 140 converts the input I data and Q data into (I ² + Q ² ) ^1/2 cos (ωt + φ) and outputs the result. However, φ is an angle formed by vectors of I data and Q data, and is expressed by φ = tan− ¹ (Q / I).

  The variable gain amplifier 150 makes the gain variable according to an instruction from an external control unit (not shown). For example, when the output power of the amplifier 160 has to be halved, the variable gain amplifier 150 reduces the power of the signal input to the amplifier 160 by doubling the gain, and the output of the amplifier 160. The power is halved. As described above, a typical example in which the gain variable amplifier 150 makes the gain variable is that another communication device that communicates with a communication device incorporating the transmission circuit 100 is near or far away from the communication device. This is the case. In such a case, the power of the transmission signal is increased or decreased by increasing or decreasing the gain of the variable gain amplifier 150.

  The amplifier 160 amplifies the modulation signal output from the vector modulator 140 and outputs the amplified signal.

  The band pass filter 170 removes unnecessary quantization noise components out of the band from the signal amplified by the amplifier 160 and outputs the result.

  As described above, the setting range in the data converter 110 is changed according to the amount of power to be output from the amplifier 160. FIG. 2 is a diagram for explaining a setting range setting method in the data converter 110. When the amount of power to be output from the amplifier 160 is small, the gain in the variable gain amplifier 150 may be small. When the gain of the variable gain amplifier 150 is small, the input power to the amplifier 160 is small, and the input power belongs to the linear region of the amplifier 160. Accordingly, in such a case, if the setting range is narrowed, the resolution is lowered even though the input power to the amplifier 160 belongs to the linear region. Therefore, the setting range is wide. Must be set to be On the other hand, when the power to be output from the amplifier 160 is large, the gain in the variable gain amplifier 150 must be large. When the gain of the variable gain amplifier 150 is large, the input power to the amplifier 160 is large, and the input power belongs to the nonlinear region of the amplifier 160. Therefore, in such a case, if the setting range is widened, the resolution does not decrease even though the input power to the amplifier 160 belongs to the non-linear region, so that the setting range becomes narrow. Must be set to In this manner, the data converter 110 narrows or widens the setting range according to the power to be output from the amplifier 160 that is information indicating the gain of the variable gain amplifier 150. Data converter 110 may adjust the setting range according to the gain of variable gain amplifier 150 itself as information indicating the gain of variable gain amplifier 150. In any case, the data converter 110 (a setting range adjustment unit 111c described later) adjusts the setting range based on information indicating the gain of the variable gain amplifier 150.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the data converter 110. In FIG. 3, the data converter 110 includes a control unit 111, a signal processing unit 112, and a switch unit 113.

The control unit 111 controls switching of the switch unit 113. FIG. 4 is a block diagram illustrating a functional configuration of the control unit 111. In FIG. 4, the control unit 111 includes an amplitude detection unit 111a, an area determination unit 111b, and a setting range adjustment unit 111c. FIG. 5 is a flowchart showing the operation of the control unit 111. Hereinafter, the operation of the control unit 111 will be described with reference to FIG. First, the amplitude detector 111a of the controller 111 detects (I ² + Q ² ) ^1/2 that is the magnitude of the amplitude of the amplitude signal corresponding to the orthogonal data represented by the I data and the Q data (step) S101). Next, the setting range adjustment unit 111c of the control unit 111 adjusts the setting range based on information indicating the gain of the variable gain amplifier 150 given from the external control unit (step S102). Next, the area determination unit 111b of the control unit 111 determines whether or not the obtained amplitude magnitude (I ² + Q ² ) ^1/2 is within the set range (step S103). Note that the operation of step S101 and the operation of S102 may be executed in the reverse order, or may be executed in parallel.

There are several possible methods for determining whether or not it is within the set range. For example, assuming that the control unit 111 is a DSP (Digital Signal Processor), (I ² + Q ² ) ^1/2 is obtained from I data and Q data, and whether or not it is within the set range exceeds a certain threshold value. You may determine by. Further, the threshold value may be determined by the control unit 111 using a dedicated digital circuit. Alternatively, the control unit 111 may be a dedicated analog circuit and the threshold may be determined using a diode.

  When it is within the set range, the area determination unit 111b of the control unit 111 switches the switch unit 113 to output the I data and the Q data as they are (step S104).

  On the other hand, if not within the set range, the area determination unit 111b of the control unit 111 performs switching so that the I data and Q data are signal-processed by the signal processing unit 112 and the I2 data and Q2 data are output (step S105).

  The data converter 110 is devised so that the delay time generated in the path from the input side to the output side coincides with the delay time generated in the path via the signal processing unit 112 when the switch unit 113 is switched. ing. For example, when the data converter 110 is realized by a DSP, the data converter 110 outputs the I data and the Q data as they are and outputs the I data and the Q data after the time required for the processing in the signal processing unit 112 has elapsed. Q data is output. In addition, when the data converter 110 is configured by a digital circuit or an analog circuit, a delay circuit that gives a delay for a time required for processing in the signal processing unit 112 is connected to the signal processing unit 112 in the switch unit 113. It is inserted between the terminal that is not present and the input terminal 101.

As described above, the setting range of the magnitude of (I ² + Q ² ) ^1/2 is defined by the linear region of the amplifier 160. The linear region of the amplifier 160 is determined by the magnitude of the input power to the amplifier 160, that is, the magnitude of the amplitude signal input to the amplifier 160. A region where the output power and the passing phase are linear (proportional relationship) with respect to the input power is a linear region. A region where the output power and the passing phase are nonlinear (not proportional) with respect to the input power is a nonlinear region.

For example, when the amplifier 160 becomes nonlinear when the input power is larger than P1, the magnitude of the power of the signal output from the variable gain amplifier 150 corresponding to the input power P1 is A1, and the gain of the variable gain amplifier 150 is If α is set, the setting range is
0 ≦ (I ² + Q ² ) ^1/2 ≦ a1
It becomes. Here, a1 is an output amplitude from the data converter 110 uniquely determined by A1 and α.
The data converter 110 can know the gain α of the variable gain amplifier 150 based on information on the magnitude of power to be output from the amplifier 160 input from an external control circuit (not shown) (hereinafter referred to as “gain α”). The same).

Further, for example, when the amplifier 160 becomes nonlinear when the input power is smaller than P2, the magnitude of the power of the signal output from the variable gain amplifier 150 corresponding to the input power P2 is A2, and the maximum input power is supported. When the magnitude of the power of the signal output from the variable gain amplifier 150 is B and the gain of the variable gain amplifier is α, the setting range is
a2 ≦ (I ² + Q ² ) ^1/2 ≦ b
It becomes. Here, a2 is an output amplitude from the data converter 110 uniquely determined by A2 and α. b is an output amplitude from the data converter 110 uniquely determined by B and α.

For example, when the input power is smaller than P3 or larger than P4 and the amplifier 160 becomes nonlinear, the magnitude of the power of the signal output from the variable gain amplifier 150 corresponding to the input power P3 is A3, and the input When the magnitude of the power of the signal output from the variable gain amplifier 150 corresponding to the power P4 is A4 and the gain of the variable gain amplifier 150 is α, the setting range is
a3 ≦ (I ² + Q ² ) ^1/2 ≦ a4
It becomes. Here, a3 is an output amplitude from the data converter 110 uniquely determined by A3 and α. a4 is an output amplitude from the data converter 110 uniquely determined by A4 and α.

  The switch unit 113 performs switching according to a control signal from the control unit 111. When the switching is performed so that the vector modulator 140 and the signal processing unit 112 are connected, the signal processing unit 112 performs delta sigma modulation on the input signal, and outputs it to the vector modulator 140 as I2 data and Q2 data. input. In other cases, the I data and Q data are input to the vector modulator 140 as they are.

  FIG. 6 is a block diagram illustrating an example of a functional configuration of the signal processing unit 112. In FIG. 6, the signal processing unit 112 includes a coordinate system conversion unit 1121, a delta sigma modulator 1122, and a multiplier 1123.

The coordinate system conversion unit 1121 converts the input I data and Q data, which are orthogonal data, into amplitude data and phase data, which are polar coordinate system data, and outputs the data. Here, the coordinate system conversion unit 1121 represents the phase data as data of an orthogonal coordinate system. That is, assuming that the amplitude data is M and the orthogonal coordinate system data representing the phase is Ip and Qp, these are expressed by the following (Expression 1) to (Expression 3). Here, it is assumed that the size of the vector formed by Ip and Qp is constant.
M = (I + Q) ^1/2 (Formula 1)
Ip = I / M (Formula 2)
Qp = Q / M (Formula 3)

  The amplitude data M output from the coordinate system conversion unit 1121 is input to the delta sigma modulator 1122. The delta sigma modulator 1122 performs delta sigma modulation on the input amplitude data M, and outputs delta sigma modulation data Md. The delta sigma modulation signal Md is input to the multiplier 1123. Here, as the delta sigma modulator 1122, a primary delta sigma modulator or a secondary delta sigma modulator may be used. The use of a higher-order delta-sigma modulator can reduce quantization noise near the desired wave frequency.

  The orthogonal data Ip and Qp representing the phase data output from the coordinate system conversion unit 1121 are input to the multiplier 1123.

Multiplier 1123 multiplies delta-sigma modulated data Md and orthogonal data Ip and Qp, respectively, and outputs the result. That is, the multiplier 1123 outputs data I2 and Q2 represented by the following (Expression 4) and (Expression 5).
I2 = Md × Ip
Q2 = Md × Qp

  In this way, the signal processor 112 outputs the delta-sigma modulated orthogonal data I2 and Q2. Since the delta-sigma modulated orthogonal data I2 and Q2 are discretized with respect to the magnitudes of the vectors of the orthogonal data I2 and Q2, it can be said that the resolution is low.

  When the output side of the data converter 110 and the signal processing unit 112 are connected by the switch unit 113, the correction unit 120 calculates the amplitude value and the phase value of the discretized orthogonal data output from the signal processing unit 112. It is corrected and input to the vector modulator 140. On the other hand, when the output side and the input side of the data converter 110 are connected by the switch unit 113, the correction unit 120 inputs the orthogonal data as it is to the vector modulator 140.

7A, B, and C are diagrams for specifically explaining the operation of the data converter 110 when the setting range is 0 ≦ (I ² + Q ² ) ^1/2 ≦ a1. FIG. 7A is a diagram schematically illustrating a setting range. In FIG. 7A, a hatched square frame indicates the set range. A white square frame indicates the outside of the setting range. FIG. 7B is a diagram illustrating a time waveform of amplitude data obtained from I data and Q data input to the data converter 110. In the example shown in FIG. 7B, there is a time waveform portion outside the set range from the threshold values a1 to b. FIG. 7C is a diagram illustrating a time waveform of amplitude data output from the data converter 110. As shown in FIG. 7C, the data converter 110 does not perform signal processing within the setting range, and performs delta-sigma modulation with the signal processing unit 112 outside the setting range for discretization.

  FIG. 8 is a diagram for specifically explaining the operation of the correction unit 120 and the basis on which distortion is suppressed. FIG. 9 is a diagram illustrating an example of a compensation table in the case where the setting range as illustrated in FIG. 7A is used. The compensation table may be provided for each gain of the variable gain amplifier 150, or may be obtained by arithmetic processing based on the gain of the variable gain amplifier 150.

  In FIG. 8, it is assumed that the magnitude of the power of the signal output from the variable gain amplifier 150 whose input power corresponds to P1 is A1. It is assumed that the power magnitude A1 corresponds to the amplitude magnitude a1 of the orthogonal data before being amplified by the variable gain amplifier 150. Further, it is assumed that the power of the signal output from the variable gain amplifier 150 whose input power corresponds to P1a is B. It is assumed that the power magnitude B corresponds to the amplitude magnitude b of the orthogonal data before being amplified by the variable gain amplifier 150. It is assumed that the power level of the signal output from the variable gain amplifier 150 corresponding to the input power P1b is B1. The power magnitude B1 is assumed to correspond to the amplitude magnitude b1 of the orthogonal data before being amplified by the variable gain amplifier 150.

  The compensation table section 130 shown in FIG. 9 corrects the magnitude of the amplitude to b1 and corrects the phase from θ to θ + θ1 when the magnitude of the input amplitude is b at a certain gain of the variable gain amplifier 150. Thus, a correction table is defined. θ + θ1 has a phase opposite to phase θ in order to suppress intermodulation distortion. That is, the phase rotation amount at P1b is represented by -θ1.

  FIG. 10A is a diagram for explaining how to obtain b1. In order to obtain the output power P0, if the amplifier 160 is linear, the input power may be Pi1. However, since the amplifier 160 is non-linear, a large input power Pi2 must be input to obtain the output power P0. The input power at this time, that is, the magnitude of the amplitude of the orthogonal data corresponding to the signal Pi2 output from the variable gain amplifier 150 is b1.

  FIG. 10B is a diagram for explaining how to obtain the phase rotation amount θ1. As shown in FIG. 10B, if the amplifier 160 has a characteristic that the phase is delayed as the input voltage increases, it can be seen that the phase is delayed by θ1 when the input voltage is Pi2. Therefore, the corrected phase may be θ + θ1.

  The correction unit 120 refers to the compensation table according to the gain in the variable gain amplifier 150. The correction unit 120 obtains the magnitude of the amplitude input from the data converter 110. When the size of the orthogonal data is b and the gain using the compensation table shown in FIG. 9, the correction unit 120 converts the input orthogonal data so that the size is b1 and the phase is θ + θ1. And output. As a result, as shown in FIG. 8, the maximum power value of the discrete portion is B1, and the corresponding supplied power is P1b. Therefore, the power of P1b is supplied to the amplifier 160. The output power corresponding to the input power P1b is the same as the output power corresponding to the input power P1a when the amplifier 160 has an ideal linearity. Further, the correction unit 120 converts the phase θ of the input orthogonal data into θ + θ1. Therefore, the linearity of the output power and the passing phase is maintained. Therefore, the amplifier 160 can output a signal without distortion.

  As described above, in the first embodiment, the transmission circuit detects the magnitude of the amplitude of the orthogonal data that is the input signal of the transmission circuit, and supplies the amplifier based on the detected magnitude of the amplitude of the input signal. If the input power belongs to the nonlinear region of the amplifier, and if it belongs to the nonlinear region, the resolution of the input signal is lowered and output. Therefore, the data converter according to the first embodiment discretizes only the portion of the input signal having power corresponding to the nonlinear region of the amplifier. Therefore, since only a part of the input signal is discretized, the quantization noise is reduced as compared with the conventional case where all of the input signal is discretized.

  By reducing the quantization noise, it is not necessary to amplify an unnecessary signal with an amplifier, so that the power consumption of the entire transmission circuit can be reduced.

  Further, the relationship between the power and phase of the input signal to the discretized amplifier and the power and phase of the output signal from the amplifier corresponding to the discretized input signal is the same as the input / output relationship in the linear region. Therefore, no distortion occurs in the amplifier.

  Further, since the quantization noise is suppressed as a whole, the quantization noise near the desired wave frequency is also suppressed. Therefore, the passage loss in the band pass filter is reduced. Further, it is not necessary to use a bandpass filter having a steep attenuation characteristic, which leads to a reduction in power consumption of the transmission circuit. As a result, the entire transmission circuit can be reduced in size.

  In this embodiment, since the resolution of the amplitude is small, the table is extremely small as compared with a case where a compensation table is prepared in a conventional transmission circuit that does not perform data conversion by the delta-sigma modulator.

  In general, there are cases where the clock frequency for discretization in the data converter is increased to reduce the quantization noise near the desired wave frequency, but in the present invention, the quantization noise has already been reduced, Since it is not necessary to increase the clock frequency of the data converter, the power consumption of the data converter is reduced.

  In the first embodiment, the data converter 110 determines whether to perform signal processing with low resolution or to output a signal as it is without performing signal processing based on the threshold determination. If data conversion is performed so that the resolution is low outside the setting range, the present invention is not limited to this.

  For example, the control unit 111 may operate the signal processing unit 112 if it is outside the setting range, and may not operate the signal processing unit 112 if it is within the setting range. This lowers the resolution outside the set range.

Further, when the input signal is not discretized, the control unit 111 operates the signal processing unit 112 so that the interval between the discrete values is narrow if the input signal is within the set range, and the discrete value if the input signal is outside the set range. it may be intervals of Ru to operate the signal processing unit 112 to be wider. In other words, the input signal is output as it is within the set range, but it may be quantized by signal processing at a narrow interval so that the quantization noise does not increase within the set range. This also reduces the resolution outside the set range.

  In the first embodiment, the modulator is not limited to the delta-sigma modulator as long as the modulator discretizes the signal. For example, a delta modulator (DM) unit or a pulse width modulator (PWM) unit may be used.

  If the quantization noise of the amplifier 160 is sufficiently small, the band pass filter 170 may be omitted.

  The data converter 110 may be realized by storing a program for realizing the above operation in a computer-readable recording medium, and reading and executing the program from the recording medium. The point which may implement | achieve the data converter 110 based on a program and CPU is the same also in other embodiment.

  In the first embodiment, the correction unit 120 corrects the amplitude and phase of the orthogonal data with reference to the compensation table. However, the correction unit 120 may store a curve indicating the characteristics of the amplifier 160 as shown in FIGS. 10A and 10B, and calculate the amplitude and phase of the corrected orthogonal data.

(Second Embodiment)
In the second embodiment, a configuration of a transmission circuit when an amplifier 160 that is distorted when input power is low will be described. In addition, since it is the same as that of 1st Embodiment except the setting range, suppose that FIG. 1, 3, 4, 5, 6 is used in 2nd Embodiment. 11A, 11B, and 11C are diagrams for specifically explaining the operation of the data converter 110 according to the second embodiment of the present invention. In the second embodiment, it is assumed that the setting range in the data converter 110 is a2 ≦ (I ² + Q ² ) ^1/2 ≦ b. As in the first embodiment, a2 and b are variable according to the gain of the variable gain amplifier 150. FIG. 11A is a diagram schematically illustrating a setting range. In FIG. 11A, a hatched square frame indicates the set range. A white square frame indicates the outside of the setting range. FIG. 11B is a diagram illustrating a time waveform of amplitude data obtained from I data and Q data input to the data converter 110. In the example illustrated in FIG. 11B, a time waveform exists in a portion other than the set range from the threshold values a2 to b. FIG. 11C is a diagram showing a time waveform of amplitude data output from the data converter 110. As shown in FIG. 11C, signal processing is not performed within the set range, and the portion outside the set range is delta-sigma modulated by the signal processing unit 112 and discretized.

  FIG. 12 is a diagram for specifically explaining the operation of the correction unit 120 according to the second embodiment and the basis on which distortion is suppressed. As shown in FIG. 12, in the nonlinear region, the supplied power is discretized into binary values of 0 or P2. When discretized so as to be 0, the output power is also 0, so no distortion occurs. However, in this case, in the second embodiment, it is necessary to provide a circuit configuration in which no power is supplied to the amplifier 160 when the input power becomes zero. This is because a switch circuit is provided between the amplifier 160 and the variable gain amplifier 150, and when the control unit of the data converter 110 corresponds to 0, the switch is turned off and no power is supplied to the amplifier 160. What is necessary is just not to be supplied.

  As described above, in the second embodiment, the transmission circuit detects the magnitude of the amplitude of the orthogonal data that is the input signal of the transmission circuit, and supplies the amplifier based on the detected magnitude of the amplitude of the input signal. If the input power belongs to the nonlinear region of the amplifier, and if it belongs to the nonlinear region, the resolution of the input signal is lowered and output. Therefore, since only a part of the input signal is discretized, the quantization noise is reduced as compared with the conventional case where all of the input signal is discretized. Further, by reducing the quantization noise, other effects similar to those of the first embodiment are produced.

(Third embodiment)
In the third embodiment, a configuration of a transmission circuit when an amplifier that distorts when input power is high and low is described. In addition, since it is the same as that of 1st Embodiment except the setting range, suppose that FIG. 1, 3, 4, 5, 6 is used in 3rd Embodiment. 13A, 13B, and 13C are diagrams for specifically explaining the operation of the data converter 110 according to the third embodiment of the present invention. In the third embodiment, it is assumed that the setting range in the data converter 110 is a3 ≦ (I ² + Q ² ) ^1/2 ≦ a4. FIG. 13A is a diagram schematically illustrating a setting range. In FIG. 13A, a hatched square frame indicates the set range. A white square frame indicates the outside of the setting range. FIG. 13B is a diagram illustrating a time waveform of amplitude data obtained from I data and Q data input to the data converter 110. In the example shown in FIG. 13B, a time waveform exists in a portion other than the set range from the threshold values a3 to a4. FIG. 13C is a diagram illustrating a time waveform of amplitude data output from the data converter 110. As shown in FIG. 13C, signal processing is not performed within the set range, and the portion outside the set range is discretized by the signal processing unit 112.

  FIG. 14 is a diagram for specifically explaining the operation of the correction unit 120 according to the third embodiment and the basis on which distortion is suppressed. As shown in FIG. 14, in the nonlinear region with higher input power, discretization is performed and orthogonal data correction is performed in the same manner as in the first embodiment. On the other hand, in the nonlinear region where the input power is lower, discretization is performed in the same manner as in the second embodiment. Therefore, in the third embodiment, quantization noise is reduced and distortion in the amplifier is suppressed.

  In the first to third embodiments, the threshold value in the data converter 110 is changed according to the gain in the variable gain amplifier 150. If the gain of the variable gain amplifier 150 is not taken into account, for example, when the gain of the variable gain amplifier 150 is ½, the amplitude input even though the power input to the amplifier 160 is low. If the size of the signal is greater than or equal to the threshold value a1, it may be converted so that the resolution of the input signal is low. However, in such a case, since the power input to the amplifier 160 is lowered by the variable gain amplifier 150, the input power may belong to a linear region in the amplifier 160. Therefore, in the first to third embodiments, when the gain of the variable gain amplifier 150 is changed, the setting range in the data converter 110 is changed accordingly. For example, when threshold determination as shown in FIG. 7A is used, the threshold value a1 may be increased when the gain of the variable gain amplifier 150 decreases, and the threshold value a1 may be decreased when the gain increases. When threshold determination as shown in FIG. 11A is used, the threshold value a2 may be increased if the gain of the variable gain amplifier 150 decreases, and the threshold value a2 may be decreased if the gain increases. When threshold determination as shown in FIG. 13A is used, the threshold values a3 and a4 may be increased when the gain of the variable gain amplifier is decreased, and the threshold values a3 and a4 may be decreased when the gain is increased.

  In the first to third embodiments, the setting range is changed based on information indicating the gain of the variable gain amplifier 150. However, the data converter 110 fixes the setting range, changes the amplitude of the orthogonal data according to the gain of the variable gain amplifier 150, and the amplitude of the orthogonal data belongs to the setting range. It may be determined whether or not. Thus, the data converter 110 can determine whether the input voltage to the amplifier 160 belongs to the non-linear region.

  When a signal is amplified without using variable gain amplifier 150, the setting range may be fixed.

(Fourth embodiment)
In the fourth embodiment of the present invention, the configuration of the signal processing unit is different from that of the first embodiment. Only the parts different from the first embodiment will be described below.

  FIG. 15 is a block diagram showing a functional configuration of the signal processing unit 112 according to the fourth embodiment of the present invention. In FIG. 15, the signal processing unit 112 includes a subtraction unit 1124, a vector integrator 1125, and a vector quantizer 1126.

The I data and Q data input to the signal processing unit 112 are input to the vector integrator 1125 via the subtractor 1124. The vector integrator 1125 integrates each of the I data and the Q data by a vector operation and outputs them as Iv and Qv. That is, when the orthogonal data string input to the vector integrator 1125 is (I _i , Q _i ) (i is a natural number), the vector integrator 1125 has (Iv, Qv) = (ΣI _i , ΣQ _i ). Is output. The output from the vector integrator 1125 is input to the vector quantizer 1126.

  The vector quantizer 1126 quantizes the vector magnitude of the output vector from the vector integrator 1125 and outputs it as Iv3 and Qv3.

The quantization in the vector quantizer 1126 is performed as follows. Let q _n (n is an integer of 1 or more) be a discrete value of the vector size. When n is 2 or more, it is assumed that q _n-1 <q _n . The vector quantizer 1126 calculates (Iv + Qv) ^1/2 with respect to (Iv, Qv) input from the vector integrator 1125. Then, the vector quantizer 1126 obtains the maximum q _n that satisfies (Expression 6). Next, using the q _n , the vector quantizer 1126 obtains the output vector (Iv3, Qv3) by (Expression 7) and (Expression 8).
q _n ≦ (Iv + Qv) ^1/2 (Formula 6)
_{Iv3 = q n · Iv / (} Iv + Qv) 1/2 ... ( Equation 7)
_{Qv3 = q n · Qv / (} Iv + Qv) 1/2 ... ( Equation 8)

  In other words, the quantization performed here is as follows. The vector quantizer 1126 uses at least two or more discrete values. The vector quantizer 1126 obtains a maximum discrete value smaller than the magnitude of the input orthogonal data vector from the two or more discrete values. Then, the vector quantizer 1126 makes the magnitude of the vector-integrated orthogonal data the maximum discrete value, and the vector-integrated orthogonal data phase is equal to the phase of the input orthogonal data. Thus, the Iv3 data and Qv3 data after quantization are obtained.

  The subtractor 1124 subtracts the output of the vector quantizer from the input data and outputs the result to the vector integrator 1125.

  Thus, in the fourth embodiment, a part of the input signal is discretized, so that the quantization noise can be reduced. Further, the same effect as in the first embodiment can be obtained.

  Hereinafter, the effect of reducing the quantization noise when the data for transmission of the W-CDMA base station is converted using the signal processing unit 112 shown in FIG. Here, as shown in FIG. 7A, the data converter 110 sets the threshold value as a1 and performs delta-sigma modulation on I data and Q data in a vector only when the magnitude of orthogonal data is larger than a1. To do. Further, the frequency for oversampling is set to 256 times the symbol rate, the peak of the input signal is limited to 10 dB, and the threshold value a1 is set to be 6 dB lower than the maximum output of the input signal. In this case, the present inventor has confirmed that the ratio of the desired wave is 97% of the total power. This shows that the quantization noise is drastically reduced in the prior art as compared with the ratio of the desired wave being 37%.

  FIG. 16A is a diagram illustrating a spectrum of a signal output from the data converter 110 that has performed threshold determination under the above conditions. On the other hand, FIG. 16B is a diagram illustrating a spectrum of a signal output from the data converter 110 when signal processing is performed in all regions. As can be seen by comparing FIG. 16A and FIG. 16B, it can be seen that quantization noise is reduced in FIG. 16A in the vicinity of the desired wave frequency and in total.

(Fifth embodiment)
FIG. 17 is a block diagram showing a configuration of a transmission circuit 200 according to the fifth embodiment of the present invention. In FIG. 17, the transmission circuit 200 includes an input terminal 101, a data converter 110, a vector modulator 140, an amplifier 260, a band pass filter 170, and an output terminal 102. In FIG. 17, parts similar to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. However, since the variable gain amplifier is omitted in FIG. 17, the data converter 110 uses a fixed setting range.

  FIG. 18 is a diagram for explaining the characteristics of the amplifier 260 and the operation of the transmission circuit 200. As shown in FIG. 18, the amplifier 260 used in the fifth embodiment has points A1 and A2 in which the proportional relationship between the input power and the output power in the linear region is maintained in the input power P1a.

  In the case of such an amplifier 260, even if no correction unit is provided as in the first embodiment, the data converter 110 discretizes the magnitude of orthogonal data by binary values of a and b. Electric power P1 and P1a can be set, and the occurrence of distortion can be suppressed.

  Also in the fifth embodiment, the setting range in the data converter 110 may be changed according to the gain of the variable gain amplifier 150 as in the first to third embodiments.

  In the fifth embodiment, the data converter 110 also fixes the setting range, changes the amplitude of the orthogonal data according to the gain, and the input power to the amplifier 160 is in the nonlinear region. It may be determined whether or not it belongs.

(Sixth embodiment)
FIG. 19 is a block diagram showing a configuration of a transmission circuit 300 according to the sixth embodiment of the present invention. 19, a transmission circuit 300 includes an input terminal 101, a data converter 110, a vector modulator 140, a correction circuit 320, a variable gain amplifier 150, an amplifier 160, a bandpass filter 170, and an output terminal 102. With. In FIG. 19, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the sixth embodiment, a correction circuit 320 for compensating for distortion generated in the amplifier 160 is provided in front of the variable gain amplifier 150. The correction circuit 320 generates and outputs a signal having an amplitude opposite to that of the distortion component generated by the amplifier 160. A signal of equal amplitude and antiphase generated by the correction circuit 320 is input to the amplifier 160 via the variable gain amplifier 150. Since the amplifier 160 receives a signal having the same amplitude and opposite phase as the distortion component, the amplifier 160 can suppress the distortion component.

  20, 21, and 22 are diagrams illustrating an example of the correction circuit 320. FIG. 20 shows a linearizer that generates a signal having an equiamplitude antiphase using the nonlinearity of the diode D1. FIG. 21 shows a linearizer that generates a signal having an equiamplitude antiphase using the nonlinearity of the diode D2. FIG. 22 shows a linearizer that generates a signal having an equal amplitude opposite phase by utilizing the nonlinearity of the FET.

  As described above, in the sixth embodiment, the distortion component generated in the amplifier 160 can be suppressed by providing the predistortion circuit configuration.

  In the sixth embodiment, as in the first to third embodiments, the data converter 110 changes the setting range based on information indicating the gain of the variable gain amplifier 150. The data converter 110 may use a fixed setting range. Also in the sixth embodiment, the data converter 110 fixes the setting range, changes the amplitude of the orthogonal data according to the gain, and the input power to the amplifier 160 is in a non-linear region. It may be determined whether or not it belongs.

(Seventh embodiment)
FIG. 23 is a diagram showing a configuration of a transmission circuit 400 according to the seventh embodiment of the present invention. 23, a transmission circuit 400 includes an input terminal 101, a data converter 410, a correction unit 120a, a compensation table unit 130a, a variable gain amplifier 150, an amplifier 160, a bandpass filter 170, and an output terminal 102. With. In FIG. 23, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  Since the basic configuration of the data converter 410 is the same as that in FIGS. 3 and 4, FIGS. 3 and 4 are used in the seventh embodiment. The seventh embodiment differs from the first embodiment in that the data converter 410 does not process orthogonal data as an input signal, but processes amplitude data. Therefore, the correction unit 120a corrects the magnitude (scalar) of the input signal based on the signal magnitude correction value defined in the compensation table. The signal processing unit 112 in the seventh embodiment may be, for example, a delta sigma modulator, a delta modulator, or a PWM modulator, which discretizes a signal. Anything is acceptable.

  FIG. 24 is a flowchart showing the operation of the control unit 111 in the data converter 410. First, the amplitude detector 111a of the controller 111 detects the amplitude of the amplitude data x that is an input signal (step S201). Next, the setting range adjustment unit 111c of the control unit 111 adjusts the setting range based on information indicating the gain of the variable gain amplifier 150 given from the external control unit (step S202). Next, the area determination unit 111b of the control unit 111 determines whether or not the detected amplitude is within the set range (step S203). The setting range here is the same as in the first embodiment except that the threshold value is determined by the input amplitude data.

  When it is within the set range, the area determination unit 111b of the control unit 111 switches the switch unit 113 so as to output the amplitude data x as it is (step S204). On the other hand, if not within the set range, the region determination unit 111b of the control unit 111 performs switching so that the signal processing unit 112 processes the amplitude data x (step S205). As a result, when the power of the amplitude data x is out of the set range, data xr having a reduced resolution is output. On the other hand, when the power of the amplitude data x is within the set range, the amplitude data x is output as it is.

  Thus, in the seventh embodiment, signal processing is not performed for the linear region of the amplifier, and signal processing is performed for the non-linear region, so that only a part of the amplitude signal is obtained. Since it is discretized, quantization noise can be reduced. Moreover, the same effect as 1st Embodiment is also acquired.

  Also in the seventh embodiment, when a signal is amplified without using the variable gain amplifier 150, the setting range may be fixed. Further, the data converter 410 may determine whether or not the input power to the amplifier 160 belongs to the nonlinear region by changing the magnitude of the amplitude data in accordance with the gain while fixing the setting range. .

  In the seventh embodiment, a bandpass filter is used. However, depending on the form of quantization noise in the delta-sigma modulator, a lowpass filter may be used instead of the bandpass filter.

(Eighth embodiment)
FIG. 25 is a block diagram showing a configuration of a transmission circuit 500 according to the eighth embodiment of the present invention. In FIG. 25, a transmission circuit 500 includes an input terminal 101, a data converter 110, a correction unit 120, a compensation table unit 130, a coordinate system conversion unit 520, an angle modulator 530, an amplitude modulator 540, A band pass filter 550 and an output terminal 102 are provided. In FIG. 25, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description will be simplified.

  Similarly to the first embodiment, the data converter 110 outputs the input baseband signal as it is if it is within the set range, and converts it to data with low resolution and outputs it if it is outside the set range.

  The signal input to the input terminal 101 is converted by the data converter 110 as described above and input to the correction unit 120. The correction unit 120 corrects the input signal and inputs it to the coordinate system conversion unit 520 in the same manner as in the first embodiment.

  The coordinate system conversion unit 520 converts the input baseband data from the orthogonal coordinate system to the polar coordinate system, and outputs amplitude data and phase data.

  The phase data is input to the angle modulator 530 and is angle-modulated. The angle modulator 530 inputs the angle-modulated phase data to the amplitude modulator 540.

  The amplitude data output from the coordinate system conversion unit 520 is input to the amplitude modulator 540.

  In the amplitude modulator 540, the output signal from the angle modulator 530 is amplitude-modulated with the amplitude data output from the coordinate system conversion unit 520. This output is input to the bandpass filter 550 to remove out-of-band quantization noise and output from the output terminal 102.

  As described above, in the fifth embodiment, signal processing is not performed for the linear region of the amplifier, and signal processing is performed and discretized for the nonlinear region, so that only a part of the amplitude signal is obtained. Will be discretized and the quantization noise will be reduced.

  In the eighth embodiment as well, a variable gain amplifier is provided between the angle modulator 530 and the amplitude modulator 540, which is the previous stage of the amplitude modulator 540, or between the angle modulator 530 and the coordinate system conversion unit 520. In this case, as in the first to third embodiments, the setting range in the data converter 110 may be changed according to the gain of the variable gain amplifier. Further, the data converter 110 changes the amplitude of the orthogonal data according to the gain while fixing the setting range, and determines whether or not the input power to the amplitude modulator 540 belongs to the nonlinear region. May be.

(Ninth embodiment)
FIG. 26 is a block diagram showing a configuration of a transmission circuit 600 according to the ninth embodiment of the present invention. In FIG. 26, a transmission circuit 600 includes a data generation unit 620, a data converter 410, an amplitude correction unit 120b, a phase correction unit 120c, a compensation table unit 130, an angle modulator 630, and an amplitude modulator 640. A band-pass filter 650 and an output terminal 102. In the ninth embodiment, parts similar to those in the fourth embodiment are denoted by the same reference numerals, and the description is simplified.

  The data generation unit 620 outputs amplitude data and phase data. The amplitude data is input to the data converter 610. The phase data output from the data generation unit 620 is corrected to the phase defined in the compensation table unit 130 in the phase correction unit 120 c and input to the angle modulator 630.

  Similarly to the fourth embodiment, the data converter 410 outputs the input baseband signal as it is if it is within the set range, and converts it into data with low resolution and outputs it if it is outside the set range. .

  The output of the data converter 410 is input to the amplitude modulator 640 after the amplitude is corrected by the amplitude correction unit 120b.

  The phase data output from the data generation unit 620 is angle-modulated by the angle modulator 630 and input to the amplitude modulator 640.

  The amplitude modulator 640 amplitude-modulates the angle-modulated wave output from the angle modulator 630 with the signal output from the data converter 610. The output of the amplitude modulator 640 is output from the output terminal 102 after the quantization noise outside the band is removed by the band pass filter 650.

  Thus, in the ninth embodiment, signal processing is not performed for the linear region of the amplifier, and signal processing is performed for the non-linear region to be discretized, so that only a part of the amplitude signal is obtained. Will be discretized and the quantization noise will be reduced.

  In the ninth embodiment as well, a variable gain amplifier is provided between the angle modulator 630 and the amplitude modulator 640, which is the previous stage of the amplitude modulator 640, or between the angle modulator 630 and the phase correction unit 120c. In this case, as in the first to third embodiments, the setting range in the data converter 410 may be changed in accordance with the gain of the variable gain amplifier. Further, the data converter 410 may determine whether or not the input power to the amplifier 160 belongs to the nonlinear region by changing the magnitude of the amplitude data in accordance with the gain while fixing the setting range. .

  Here, it is assumed that the amplitude modulators 540 and 640 in the eighth and ninth embodiments have characteristics as shown in FIG. 12, for example. Here, when the lower limit voltage of the linear region is P2, the data converters 110 and 410 control the supply voltage to the amplitude modulators 540 and 640 to be 0 or P2 when the threshold is a2 or less. That is, the data converters 110 and 410 quantize to 0 and P2 in a region smaller than the threshold value a2. As a result, the influence of nonlinearity at a voltage smaller than P2 can be eliminated, and low distortion can be realized.

  Further, it is assumed that the amplitude modulators 540 and 640 in the eighth and ninth embodiments have characteristics as shown in FIG. 14, for example. Here, the lower limit voltage of the linear region is P3, and the upper limit is P4. The data converters 110 and 410 control the supply voltage to the amplitude modulators 540 and 640 to be 0 or P3 when the threshold value a3 or less. That is, the data converters 110 and 410 quantize to 0 and P3 in the region smaller than the threshold value a3. As a result, the influence of nonlinearity at a voltage smaller than P3 can be eliminated, and low distortion can be realized. Further, the data converters 110 and 410 control the supply voltage to the amplitude modulators 540 and 640 to be P4 or P4b when the threshold value is a4 or more. That is, the data converters 110 and 410 quantize into P4 and P4b in a region larger than the threshold value a4. As a result, the influence of nonlinearity at a voltage larger than P4 can be eliminated, and low distortion can be realized.

  In the eighth and ninth embodiments, the bandpass filters 550 and 650 may be omitted when the quantization noise of the signals output from the amplitude modulators 540 and 640 is sufficiently small.

  In the eighth and ninth embodiments, a correction circuit that compensates for distortion may be connected to the preceding stage of the amplitude modulator 540 as in the sixth embodiment.

  In each of the above embodiments, quantization is performed to binary values of 0 and a positive real number. However, quantization may be performed to multi-values higher than that.

  FIG. 27A is a block diagram showing a functional configuration of an audio device 700 to which the data converter of the present invention is applied. 27A, the audio device 700 includes a data converter 110 (or 410), an amplifier 160, a filter 701, and a speaker 702. The data converter 110 (or 410) is a data converter of the present invention. All the modifications described above are applicable to the data converter 110 (or 410). The filter 701 is generally a low-pass filter. Audio device 700 shown in FIG. 27A does not use a variable gain amplifier. However, when using a variable gain amplifier, the data converter 110 (or 410) adjusts the setting range according to the gain. If the data converter 110 (or 410) determines that the input voltage to the amplifier 160 belongs to the non-linear region, the data converter 110 (or 410) may input audio data (or quadrature data or amplitude data) as an input signal. The signal is converted into a signal having a lower resolution than the input signal and output. The amplifier 160 amplifies the signal output from the data converter 110 (or 410). The signal amplified by the amplifier 160 is sent to the speaker 702 via the filter 701 and converted into sound. As a result, an audio device in which quantization noise is suppressed and power consumption is reduced is provided.

  FIG. 27B is a block diagram showing a functional configuration of the video equipment 800 to which the data converter of the present invention is applied. 27B, the video equipment 800 includes a data converter 110 (or 410), an amplifier 160, a filter 801, and a display 802. The data converter 110 (or 410) is a data converter of the present invention. All the modifications described above are applicable to the data converter 110 (or 410). The filter 801 is generally a low-pass filter. The video equipment 800 shown in FIG. 27B does not use a variable gain amplifier. However, when using a variable gain amplifier, the data converter 110 adjusts the setting range according to the gain. When the data converter 110 (or 410) determines that the input voltage to the amplifier 160 belongs to the non-linear region, the data converter 110 (or 410) may input video data (or quadrature data or amplitude data) as an input signal. The signal is converted into a signal having a lower resolution than the input signal and output. The amplifier 160 amplifies the signal output from the data converter 110 (or 410). The signal amplified by the amplifier 160 is sent to the display 802 via the filter 801 and converted into video and / or audio. As a result, a video device in which quantization noise is suppressed and power consumption is reduced is provided.

  The data converter of the present invention can be applied to all electronic devices using an amplifier, and the application range is not limited to communication devices, audio devices, and video devices.

  In the above embodiment, the input signal to the data converter of the present invention is a digital signal, but may be an analog signal. Similarly, when the analog signal is an input signal, the data converter according to the present invention determines whether or not the amplitude of the analog signal is within the set range so that the input voltage to the amplifier is in a nonlinear region. It is sufficient to determine whether or not it belongs to.

  Although the present invention has been described in detail above, the above description is merely illustrative of the present invention in all respects and is not intended to limit the scope thereof. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.

  The data converter according to the present invention can suppress quantization noise and reduce power consumption, and can be applied to communication devices such as mobile phones and wireless LANs, and electronic devices such as audio devices and video devices. be able to.

1 is a block diagram showing a configuration of a transmission circuit 100 according to a first embodiment of the present invention. The figure for demonstrating the setting method of the setting range in the data converter 110 The block diagram which shows an example of a functional structure of the data converter 110 The block diagram which shows the functional structure of the control part 111 A flowchart showing the operation of the control unit 111 The block diagram which shows an example of a functional structure of the signal processing part 112 Diagram for specifically explaining the operation of the data converter 110 when the setting range is ^{0 ≦ (I 2 + Q 2} ) 1/2 ≦ a1 Diagram for specifically explaining the operation of the data converter 110 when the setting range is ^{0 ≦ (I 2 + Q 2} ) 1/2 ≦ a1 Diagram for specifically explaining the operation of the data converter 110 when the setting range is ^{0 ≦ (I 2 + Q 2} ) 1/2 ≦ a1 The figure for demonstrating specifically the operation | movement of the correction | amendment part 120, and the grounds by which distortion is suppressed. The figure which shows a compensation table at the time of using a setting range as shown to FIG. 7A. A figure for explaining how to find b1 The figure for demonstrating how to obtain | require phase rotation amount (theta) 1 The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 2nd Embodiment of this invention. The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 2nd Embodiment of this invention. The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 2nd Embodiment of this invention. The figure for demonstrating concretely the reason the operation | movement of the correction | amendment part 120 which concerns on 2nd Embodiment, and distortion are suppressed. The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 3rd Embodiment of this invention. The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 3rd Embodiment of this invention. The figure for demonstrating concretely operation | movement of the data converter 110 which concerns on the 3rd Embodiment of this invention. The figure for demonstrating concretely the reason the operation | movement of the correction | amendment part 120 which concerns on 3rd Embodiment, and distortion are suppressed. The block diagram which shows the functional structure of the signal processing part 112 which concerns on the 4th Embodiment of this invention. The figure which shows the spectrum of the signal output from the data converter 110 which performed the threshold determination The figure which shows the spectrum of the signal output from the data converter 110 when signal processing is performed in all the areas. The block diagram which shows the structure of the transmission circuit 200 which concerns on the 5th Embodiment of this invention. The figure for demonstrating the characteristic of the amplifier 260, and operation | movement of the transmission circuit 200 The block diagram which shows the structure of the transmission circuit 300 which concerns on the 6th Embodiment of this invention. The figure which shows an example of the correction circuit 320 The figure which shows an example of the correction circuit 320 The figure which shows an example of the correction circuit 320 The figure which shows the structure of the transmission circuit 400 which concerns on the 5th Embodiment of this invention. Flowchart showing operation of control unit 111 in data converter 410 The block diagram which shows the structure of the transmission circuit 500 which concerns on the 8th Embodiment of this invention. The block diagram which shows the structure of the transmission circuit 600 which concerns on the 9th Embodiment of this invention. The block diagram which shows the functional structure of the audio equipment 700 to which the data converter of this invention is applied. The block diagram which shows the functional structure of the video equipment 800 to which the data converter of this invention is applied. The block diagram which shows the structure of the conventional communication apparatus 900 28 is a block diagram showing an example of the configuration of the transmission circuit 901 in the conventional communication device 900 shown in FIG. Block diagram showing the configuration of the amplitude modulator 930 Schematic diagram for explaining the cause of distortion 28 is a block diagram showing another configuration example of the transmission circuit in the conventional communication device 900 shown in FIG. The figure which shows the output spectrum from the amplitude modulator 930 of the transmission circuit 901a shown in FIG. The figure which shows the output spectrum from the band pass filter 940 of the transmission circuit 901a shown in FIG.

Explanation of symbols

100, 200, 300, 400, 500, 600 Transmission circuit 101 Input terminal 102 Output terminal 110, 410 Data converter 111 Control unit 111a Amplitude detection unit 111b Area determination unit 111c Setting range adjustment unit 112 Signal processing unit 1121 Coordinate system conversion unit 1122 Delta Sigma Modulator 1123 Multiplier 1124 Subtractor 1125 Vector Integrator 1126 Vector Quantizer 113 Switch Unit 120 Correction Unit 130 Compensation Table Unit 140 Vector Modulation Unit 150 Variable Gain Amplifier 160, 260 Amplifiers 170, 550, 650 Bandpass Filter 320 Correction circuit 520 Coordinate system conversion unit 530, 630 Angle modulator 540, 640 Amplitude modulator 620 Data generation unit 700 Audio device 800 Video device 701, 801 Filter 702 Speaker 802 D Play

Claims (18)

An input signal that transmits information using at least amplitude, amplifies a non-discretized input signal to a predetermined level, and outputs the amplified signal by reducing quantization noise by a filter. Is a data converter that converts the signal into a signal for input to the amplifier and outputs the signal.
An amplitude detector for detecting the amplitude of the input signal;
A region determination unit that determines whether the amplitude of the input signal to the amplifier belongs to a nonlinear region of the amplifier based on the amplitude of the input signal detected by the amplitude detection unit;
When the region determination unit determines that the amplitude of the input signal to the amplifier does not belong to the nonlinear region of the amplifier, the input signal is output as it is, and the amplitude of the input signal to the amplifier is And a signal processing unit that discretizes the input signal by delta-sigma modulation or vector quantization and outputs the discretized signal when it is determined that the signal belongs to the nonlinear region of the amplifier. The signal processing section further by the area determination unit, when the magnitude of the amplitude of the input signal to the amplifier is determined to not belong to the non-linear region of the amplifier, instead of directly outputting the input signal Then, the amplitude of the input signal is converted into a discretized signal so that the interval between the discrete values is narrower than in the discretization processing in the case where it is determined to belong to the nonlinear region, and the converted signal and it outputs the data converter according to claim 1.   2. The data converter according to claim 1, wherein when the input signal is orthogonal data, the amplitude detector detects the magnitude of the amplitude of the input signal by obtaining a square root of the sum of squares thereof.   The data converter according to claim 1, wherein the region determination unit determines that the input voltage to the amplifier belongs to a nonlinear region when the magnitude of the amplitude of the input signal exceeds a first threshold value. The data converter according to claim 1, wherein the region determination unit determines that the input signal belongs to a non-linear region when the amplitude of the input signal does not exceed a second threshold value.   2. The data converter according to claim 1, wherein the region determination unit determines that the input signal belongs to a nonlinear region when the magnitude of the amplitude of the input signal does not exceed a third threshold or exceeds a fourth threshold. . The amplifier receives a signal amplified by a variable gain amplifier,
The region determination unit determines whether or not an input voltage to the amplifier belongs to the nonlinear region of the amplifier based on whether or not the magnitude of the amplitude of the input signal is outside a setting range.
The data converter according to claim 1, further comprising a setting range adjustment unit that adjusts the setting range based on information indicating a gain of the variable gain amplifier. The signal processing unit
A coordinate system conversion unit for converting the input signal into amplitude data and phase data;
A delta-sigma modulator that delta-sigma modulates the amplitude data converted by the coordinate system conversion unit;
The data converter according to claim 1, further comprising a multiplier that multiplies the phase data by the amplitude data that is delta-sigma modulated by the delta-sigma modulator. The input signal is orthogonal data,
The signal processing unit
A subtractor to which the input signal is input;
A vector integrator connected to the subtractor for integrating each element of the orthogonal data;
For the orthogonal data integrated by the vector integrator, at least two or more discrete values are used, and the maximum discrete value smaller than the vector size of the input orthogonal data is selected from the two or more discrete values. The magnitude of the vector formed by the integrated orthogonal data is the maximum discrete value, and the phase of the integrated orthogonal data is equal to the phase of the input orthogonal data. A vector quantizer for quantizing,
The data converter according to claim 1, wherein the subtractor subtracts orthogonal data quantized by the vector quantizer from input orthogonal data. A transmission circuit for generating a transmission signal,
An amplifier;
A filter for reducing quantization noise of an output signal of the amplifier;
A data converter for transmitting information using at least amplitude and converting a non-discretized input signal to a signal used as an input of the amplifier;
The data converter is
An amplitude detector for detecting the amplitude of the input signal;
A region determination unit that determines whether the amplitude of the input signal to the amplifier belongs to a nonlinear region of the amplifier based on the amplitude of the input signal detected by the amplitude detection unit;
When the region determination unit determines that the amplitude of the input signal to the amplifier does not belong to the nonlinear region of the amplifier, the input signal is output as it is, and the amplitude of the input signal to the amplifier is A signal processing unit that discretizes the input signal by delta-sigma modulation or vector quantization and outputs the discretized signal when the signal is determined to belong to the nonlinear region of the amplifier. In addition, a variable gain amplifier for adjusting the power of the signal input to the amplifier,
The region determination unit determines whether the amplitude of the input signal to the amplifier belongs to the nonlinear region based on whether the amplitude of the input signal is outside a predetermined setting range. Judgment
The transmission circuit according to claim 10 , wherein the data converter further includes a setting range adjustment unit that adjusts the setting range based on information indicating a gain of the variable gain amplifier. The input signal to the data converter is orthogonal data;
The data converter outputs the orthogonal data after conversion,
Furthermore, a vector modulator that modulates and outputs the orthogonal data after conversion output by the data converter,
The transmission circuit according to claim 10 , wherein the amplitude detection unit detects the magnitude of the amplitude of the input signal based on the orthogonal data. The input signal to the data converter is orthogonal data;
The data converter outputs the orthogonal data after conversion,
Furthermore, the coordinate system conversion unit that converts the orthogonal data after the conversion into polar coordinate system data to generate amplitude data and phase data;
An angle modulator for angle-modulating the phase data generated by the coordinate system conversion unit,
The amplifier is an amplitude modulator that modulates the amplitude of the phase data angle-modulated by the angle modulator based on the amplitude data generated by the coordinate system conversion unit,
The transmission circuit according to claim 10 , wherein the amplitude detection unit detects a magnitude of an amplitude of an input signal based on the orthogonal data. Furthermore, a data generation unit that generates amplitude data and phase data;
An angle modulator that angle-modulates the phase data generated by the data generation unit to generate an angle-modulated wave;
The input signal to the data converter is the amplitude data generated by the data generation unit,
The data converter outputs the converted amplitude data,
The amplitude detection unit detects the amplitude of the input signal based on the amplitude data,
The amplifier is an amplitude modulator that modulates the amplitude of the phase data angle-modulated by the angle modulator based on the amplitude data converted by the data converter,
The transmission circuit according to claim 10 , wherein the amplitude detection unit detects the magnitude of the amplitude of the input signal based on the magnitude of the amplitude data. Communication equipment,
A transmission circuit for generating a transmission signal;
A receiving circuit for processing the received signal,
The transmission circuit includes:
An amplifier;
A filter for reducing quantization noise of an output signal of the amplifier;
A data converter for transmitting information using at least amplitude and converting a non-discretized input signal to a signal used at the input of the amplifier;
The data converter is
An amplitude detector for detecting the amplitude of the input signal;
A region determination unit that determines whether the amplitude of the input signal to the amplifier belongs to a nonlinear region of the amplifier based on the amplitude of the input signal detected by the amplitude detection unit;
When the region determining unit determines that the amplitude of the input signal to the amplifier does not belong to the nonlinear region of the amplifier, the input signal is output as it is, and the amplitude of the input signal to the amplifier is A signal processing unit that discretizes the input signal by delta-sigma modulation or vector quantization and outputs the discretized signal when it is determined that the signal belongs to the nonlinear region of the amplifier. An electronic device that amplifies a non-discretized input signal to a predetermined level, transmitting information using at least amplitude ,
An amplifier;
A filter for reducing quantization noise of an output signal of the amplifier;
And a data converter for converting a signal for inputting the input signal to the amplifier,
The data converter is
An amplitude detector for detecting the amplitude of the input signal;
A region determination unit that determines whether the amplitude of the input signal to the amplifier belongs to a nonlinear region of the amplifier based on the amplitude of the input signal detected by the amplitude detection unit;
When the region determining unit determines that the amplitude of the input signal to the amplifier does not belong to the nonlinear region of the amplifier, the input signal is output as it is, and the amplitude of the input signal to the amplifier is An electronic device comprising: a signal processing unit that discretizes the input signal by delta-sigma modulation or vector quantization and outputs the discretized signal . The input provided in a device for amplifying a non-discretized input signal, which transmits information using at least amplitude, to a predetermined level, and outputting the amplified signal by reducing quantization noise by a filter A processing method in a data converter for converting a signal into a signal for input to an amplifier,
Detecting the amplitude of the input signal;
Determining whether the magnitude of the amplitude of the input signal to the amplifier belongs to a non-linear region of the amplifier based on the sensed magnitude of the amplitude of the input signal;
When it is determined that the amplitude of the input signal to the amplifier does not belong to the nonlinear region of the amplifier, the input signal is output as it is, and the amplitude of the input signal to the amplifier is nonlinear. And discretizing the input signal by delta-sigma modulation or vector quantization and outputting the discretized signal if determined to belong to a region. In the step of determining whether or not the amplifier belongs to a non-linear region, the amplitude of the input signal to the amplifier is determined based on whether or not the amplitude of the input signal is outside a setting range. Determine whether it belongs to the nonlinear region of the amplifier,
The method according to claim 17 , further comprising adjusting the setting range based on information indicating a gain of a variable gain amplifier connected to a front stage of the amplifier.

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