JP2005295521A - Data converter device and data conversion method, and transmitter circuit, communications device and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter circuit that is capable of suppressing quantization noise and operating with a high efficiency, a data converter section and a data conversion method for use therein, and a communications device. <P>SOLUTION: The present invention is a data converter section which performs a predetermined data conversion operation in an input signal and outputs the input signal. The data converter section includes: a signal processing section for digitizing the input signal to generate a signal having a lower resolution magnitude-wise than that of the input signal; a subtractor section for subtracting the input signal from the signal having a lower resolution to extract quantization noise; a filter for extracting quantization noise near an intended wave frequency; and a subtractor section for removing the quantization noise near the intended wave frequency from the signal having a lower resolution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmission circuit used in a communication device such as a mobile phone and a wireless LAN, and an electronic device such as an audio device and a video device, and a data conversion unit and a data conversion method used in the electronic device. The present invention relates to a transmission circuit, a communication device, an electronic device, a data converter used in the transmission circuit, and a data conversion method that are small and capable of operating with high efficiency.

  Communication devices provided on the terminal side of mobile communication systems such as mobile phones and wireless LANs are required to operate with low power consumption while ensuring linearity of output signals within a wide power amplification range. Accordingly, such a communication device is required to have a transmission circuit capable of performing power amplification of the output signal with low power consumption while ensuring the linearity of the output signal.

  FIG. 33 is a block diagram showing an example of the configuration of a conventional communication device. 33, a conventional communication device includes a transmission circuit 900, a reception circuit 951, an antenna duplexer 952, and an antenna 953. The high-frequency transmission signal generated by the transmission circuit 900 is radiated from the antenna 953 to the space via the antenna duplexer 952. On the other hand, the high-frequency signal received by the antenna 953 is sent to the receiving circuit 951 via the antenna duplexer 952 and subjected to reception processing. As the antenna duplexer 952, for example, a duplexer using a switch, a derivative, a SAW (Surface Acoustic Wave) filter, an FBAR (Film Bulk Acoustic Resonator) filter, or the like is used.

  An example of a transmission circuit 900 used in a conventional communication device is disclosed in Japanese Patent Laid-Open No. 2002-325109. FIG. 34 is a block diagram showing an example of the configuration of a conventional transmission circuit 900. As shown in FIG. Hereinafter, the transmission circuit 900 shown in FIG. 34 is referred to as a first conventional transmission circuit. 34, the transmission circuit of the first conventional example includes a data generation unit 901, an output terminal 902, a delta-sigma modulator 903, an angle modulation unit 904, a voltage control unit 905, an amplitude modulation unit 906, and a bandpass filter 907. Prepare.

  The data generation unit 901 generates amplitude data and phase data as data to be transmitted. The amplitude data is input to the delta sigma modulator 903. The delta sigma modulator 903 performs delta sigma modulation on the amplitude data and outputs a delta sigma modulated signal. The delta sigma modulation signal is input to the voltage control unit 905. The voltage control unit 905 supplies the voltage controlled by the delta sigma modulation signal to the amplitude modulation unit 906.

  On the other hand, the phase data is input to the angle modulation unit 904. The angle modulation unit 904 angle-modulates the phase data and outputs an angle-modulated wave signal. The amplitude modulation unit 906 performs amplitude modulation on the angle modulation wave signal with the voltage supplied from the voltage control unit 905 to generate a modulation wave signal. The modulated wave signal generated by the amplitude modulation unit 906 is input to the band pass filter 907. The band pass filter 907 removes unnecessary components outside the band from the modulated wave signal generated by the amplitude modulation unit 906. The modulated wave signal from which unnecessary components are removed by the band-pass filter 907 is output via a terminal 902.

  For example, when the amplitude data is delta-sigma-modulated with binary values of 0 and real numbers, the delta-sigma modulator 903 outputs a delta-sigma modulated signal discretized into binary values of 0 and real numbers. That is, the delta-sigma modulated signal has only two states of on / off, and the level of the on state is constant, so that it is a signal that is not easily affected by the nonlinearity of the amplitude modulation unit 906. Therefore, the transmission circuit of the first conventional example can output a transmission signal with less distortion.

  In addition to the transmission circuit described above, a transmission circuit 900 used in a conventional communication device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-072734. FIG. 35 is a block diagram showing an example of the configuration of a conventional transmission circuit 900. Hereinafter, the transmission circuit 900 shown in FIG. 35 is referred to as a second conventional transmission circuit. 35, the second conventional transmission circuit includes an input terminal 911, a data converter 912, an amplifier 913, a bandpass filter 914, and an output terminal 915.

The data conversion unit 912 performs predetermined data conversion on the input signal input via the input terminal 911, and outputs a signal having a resolution lower than that of the input signal. Specifically, the data conversion unit 912 performs delta sigma modulation on the amplitude data that is the amplitude component included in the input signal, and multiplies the amplitude data that has been delta sigma modulated by the phase data that is the phase component included in the input signal. As a result, a signal having a lower resolution than the input signal is generated. The amplifier 913 amplifies the signal output from the data conversion unit 912 and outputs the amplified signal to the bandpass filter 914. The bandpass filter 914 removes quantization noise generated during delta-sigma modulation from the signal amplified by the amplifier 913. The signal from which the quantization noise is removed is output via the output terminal 915.
JP 2002-325109 A JP 2004-072734 A JP 2004-072735 A S. R. Norsworthy et al., “Delta-Sigma Data Converters”, 1996 Eye Triple E (1996 IEEE)

  However, the first and second conventional transmission circuits have the following problems. This problem will be described using the first conventional transmission circuit (see FIG. 34). In the transmission circuit of the first conventional example, the modulated wave signal output from the amplitude modulation unit 906 includes quantization noise generated during delta-sigma modulation up to a relatively close vicinity of the desired wave frequency. FIG. 36 is a diagram illustrating a waveform example of a modulated wave signal output from the amplitude modulation unit 906. In FIG. 36, the frequency on the horizontal axis represents the deviation from the center frequency (desired wave frequency) of the modulated wave signal. From FIG. 36, it is confirmed that the modulated wave signal contains quantization noise at a high level up to a relatively close vicinity of the desired wave frequency. Therefore, the bandpass filter 907 that removes quantization noise is required to have a steep attenuation characteristic. With the bandpass filter 907 having such characteristics, it is difficult to reduce the signal passing loss and to reduce the physical size.

  In addition, when the transmission circuit changes the band of the transmission frequency, the band-pass filter 907 having a steep attenuation characteristic needs to frequently change the band of the signal to be passed (signal pass band). FIG. 37 is a diagram illustrating an example of characteristics necessary for the bandpass filter 907 in the conventional transmission circuit. In FIG. 37, the band-pass filter 907 changes the signal pass band as A to D every time the transmission circuit changes the band of the transmission frequency. In order to realize the characteristics shown in FIG. 37, the bandpass filter 907 needs to be provided with a variable capacitance element such as a varactor. However, such a bandpass filter 907 has a problem that a loss occurs due to a varactor and a circuit scale increases.

  Further, in the conventional transmission circuit, if the quantization noise generated at the time of delta-sigma modulation is reduced without obtaining a steep attenuation characteristic in the band-pass filter 907, for example, the clock frequency of the delta-sigma modulator 903 is increased. Is required. However, the delta sigma modulator 903 has problems that the power consumption increases and the circuit scale increases when the clock frequency is increased. That is, in the first and second conventional transmission circuits, it is necessary to use a bandpass filter 907 having a steep attenuation characteristic, a delta-sigma modulator 903 that operates at a high clock frequency, and the like. In addition, there is a problem that it is difficult to realize low power consumption.

  As a conventional transmission circuit for solving such a problem, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2004-072735. FIG. 38 is a block diagram showing an example of the configuration of a conventional transmission circuit 900. Hereinafter, the transmission circuit 900 shown in FIG. 38 is referred to as a third conventional transmission circuit. 38, the third conventional transmission circuit includes an input terminal 921, a signal processing unit 922, a first signal generation source 923, a second signal generation source 924, a main amplifier 925, an auxiliary amplifier 926, and a combiner 927. And an output terminal 928.

  The signal processing unit 922 generates a signal X1 output to the first signal generation source 923 and a signal X2 output to the second signal generation source 924 based on the signal X0 input via the input terminal 921. To do. The signal X1 output to the first signal generation source 923 is obtained by delta-sigma modulation of the input signal X0. The signal X2 output to the second signal generation source 924 is obtained by removing the input signal X0 from the signal X1 output to the first signal generation source 923.

  The first signal generation source 923 generates a binary or multilevel discrete analog signal and outputs the generated signal to the main amplifier 925. The signal output from the first signal generation source 923 is, for example, a binary analog signal obtained by performing delta-sigma modulation on the input signal X1 to the first signal generation source 923, and the first signal generation This is a signal including a component of the input signal X1 to the source 923 and a component of quantization noise generated when performing delta-sigma modulation. On the other hand, the second signal generation source 924 outputs a signal corresponding to the quantization noise component of the signal output from the first signal generation source 923.

  The main amplifier 925 amplifies the signal output from the first signal generation source 923 and outputs the amplified signal to the combiner 927. The auxiliary amplifier 926 amplifies the signal output from the second signal generation source 924 and outputs the amplified signal to the combiner 927. The combiner 927 removes quantization noise included in the signal output from the first signal generation source 923 based on the signals output from the main amplifier 925 and the auxiliary amplifier 926. Specifically, the synthesizer 927 determines that the quantization noise included in the signal output from the first signal generation source 923 is equal to the signal output from the second signal generation source 924 (that is, quantization noise). By adjusting the amplitude to be opposite in phase and synthesizing these signals, quantization noise is removed from the signal output from the first signal generation source 923. The signal synthesized by the synthesizer 927 is output via the output terminal 928. As a result, the third conventional transmission circuit can suppress quantization noise without using a bandpass filter having a steep attenuation characteristic, a delta-sigma modulator operating at a high clock frequency, or the like.

  However, in the transmission circuit of the third conventional example (see FIG. 38), a signal that is delta-sigma modulated by the first signal generation source 923 (that is, a signal including a desired wave signal and quantization noise), The signals generated by the second signal generation source 924 (that is, quantization noise) are amplified separately, and then synthesized in an analog manner by a synthesizer 927 to remove the quantization noise. Therefore, in the transmission circuit of the third conventional example, since the path until the signal is combined by the combiner 927 is long and the number of analog parts increases, the signal size, phase, and delay time in each path are reduced. Matching control becomes troublesome, and there has been a problem that miniaturization and low power consumption of the circuit cannot be sufficiently promoted.

  Therefore, an object of the present invention is to provide a transmission circuit, a communication device, an electronic device, a data converter, and a data conversion used in the transmission circuit, a small size, and a high-efficiency operation that suppress quantization noise without troublesome control. Is to provide a method.

  The present invention is directed to a data converter that performs predetermined data conversion on an input signal and outputs the converted signal. And in order to achieve the said objective, the data converter of this invention is provided with the 1st calculating part, the 2nd calculating part, the 3rd calculating part, and the 4th calculating part.

  The first arithmetic unit discretizes the input signal and generates a signal having a resolution lower than that of the input signal. The second calculation unit extracts the quantization noise component generated in the first calculation unit from the low resolution signal generated by the first calculation unit. The third calculation unit extracts a quantization noise component near the desired wave frequency, which is the center frequency, from the quantization noise component extracted by the second calculation unit. The fourth calculation unit is configured to input the input signal based on the low resolution signal generated by the first calculation unit and the quantization noise component near the desired wave frequency extracted by the third calculation unit. A signal obtained by removing a quantization noise component in the vicinity of a desired wave frequency from a signal having a lower resolution with respect to the size is output.

  Moreover, the data converter of this invention can also be set as the following structures. The first arithmetic unit includes a signal processing unit that quantizes an input signal and generates a signal having a resolution lower than that of the input signal. The second calculation unit includes a first subtraction unit that subtracts an input signal from a low-resolution signal generated by the signal processing unit and extracts a quantization noise component generated in the signal processing unit. The third calculation unit band-limits the quantization noise component extracted by the first subtraction unit with a predetermined cutoff frequency, and a quantization noise component near the desired wave frequency that is the center frequency of the input signal Is provided. The fourth arithmetic unit subtracts the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low-resolution signal generated by the signal processing unit, so that the magnitude is larger than the input signal. A second subtraction unit is provided that outputs a signal obtained by removing a quantization noise component in the vicinity of a desired wave frequency from a signal with low resolution.

  Preferably, when the input signal is orthogonal data, the signal processing unit includes a coordinate conversion unit, a delta-sigma modulator, and a multiplication unit. The coordinate conversion unit generates amplitude data indicating the size of the orthogonal data, divides the amplitude data from the orthogonal data, and generates phase data, thereby converting the orthogonal data into coordinate data and amplitude data. That is, the phase data is output as data represented by an orthogonal coordinate system. The delta sigma modulator performs delta sigma modulation on the amplitude data to a binary value or more, thereby reducing the resolution of the amplitude data. The multiplication unit multiplies the amplitude data that has been delta-sigma modulated by the delta-sigma modulator and the phase data, and outputs a signal having a resolution lower than that of the orthogonal data.

  When the input signal is orthogonal data, the signal processing unit may include at least one subtraction unit, at least one vector integration unit, and a vector quantization unit. Orthogonal data is input to the subtraction unit. The vector integration unit is connected to the subtraction unit and integrates each element of the orthogonal data. The vector quantization unit uses at least two or more discrete values for the orthogonal data integrated by the vector integration unit, and the maximum discrete value whose integrated orthogonal data size is smaller than the input orthogonal data size. The signal is quantized so that the phase of the integrated orthogonal data becomes equal to the phase of the input orthogonal data, and a signal having a resolution lower than that of the input orthogonal data is output. The subtraction unit subtracts the orthogonal data quantized by the vector quantization unit from the input orthogonal data.

  As another embodiment, when the input signal is a modulated wave signal modulated based on orthogonal data, the signal processing unit includes a delta-sigma modulator. The delta sigma modulator outputs a signal having a resolution lower than that of the input modulated wave signal, for example, by performing delta sigma modulation on the input signal to two or more values.

  For example, when the zero point of the noise transfer function in the signal processing unit is 1, the filter included in the data conversion device is a low-pass filter.

  For example, when the zero point of the noise transfer function in the signal processing unit is a complex number of size 1, the filter included in the data conversion device is a bandpass filter.

  In addition, when the filter is a low-pass filter, the cutoff frequency of the filter included in the data converter is preferably smaller than ½ of the sampling frequency in the signal processing unit. In addition, when the filter is a band-pass filter, the cutoff frequency of the filter included in the data converter is larger than the frequency obtained by subtracting 1/2 of the sampling frequency from the center frequency of the input signal. It is preferably smaller than the frequency obtained by adding 1/2 of the sampling frequency to the center frequency.

  The present invention is also directed to a transmission circuit that performs predetermined processing on an input signal and outputs a transmission signal. In order to achieve the above object, the transmission circuit of the present invention includes a data conversion unit, a modulation amplification unit, and a bandpass filter.

  The data converter receives all or part of the input signal, performs predetermined data conversion on the input signal, and outputs the result. The modulation amplification unit performs at least one of modulation and amplification based on the signal converted by the data conversion unit. The band-pass filter outputs a transmission signal by removing unnecessary components outside the band at a predetermined cutoff frequency from the signal that has been modulated or amplified by the modulation amplification unit. More specifically, the data conversion unit includes a signal processing unit, a first subtraction unit, a filter, and a second subtraction unit.

  The signal processing unit discretizes the input signal and generates a signal having a resolution lower than that of the input signal. The first subtracting unit subtracts the input signal from the low resolution signal generated by the signal processing unit, and extracts the quantization noise component generated in the signal processing unit. The filter band-limits the quantization noise component extracted by the first subtraction unit with a predetermined cut-off frequency, and extracts a quantization noise component near the desired wave frequency that is the center frequency of the input signal. The second subtracting unit subtracts the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low-resolution signal generated by the signal processing unit, thereby resolving the resolution with respect to the magnitude of the input signal. A signal obtained by removing the quantization noise component in the vicinity of the desired wave frequency from the low signal is output.

  When the input signal is orthogonal data, the orthogonal data is input to the data conversion unit. The modulation amplification unit includes a vector modulation unit that modulates the signal converted by the data conversion unit, and an amplification unit that amplifies the signal modulated by the vector modulation unit to a predetermined output level.

  For example, the vector modulation unit can modulate the signal converted by the data conversion unit by orthogonal modulation.

  As another embodiment, when the input signal is orthogonal data, orthogonal data is input to the data conversion unit. In this case, the modulation amplification unit includes a polar coordinate system conversion unit, an angle modulation unit, an amplitude modulation unit, and a voltage control unit. The polar coordinate system conversion unit converts the signal converted by the data conversion unit into polar coordinate data and outputs amplitude data and phase data. The angle modulation unit outputs an angle-modulated wave signal by angle-modulating the phase data. The amplitude modulation unit amplitude-modulates the angle-modulated wave signal with a voltage corresponding to the magnitude of the amplitude data. The voltage control unit controls the voltage supplied to the amplitude modulation unit according to the magnitude of the amplitude data.

  As another embodiment, when the input signal is a modulated wave signal modulated based on orthogonal data, the modulated wave signal is input to the data converter. In this case, the modulation amplification unit includes an amplification unit that amplifies the signal converted by the data conversion unit to a predetermined output level.

  As another embodiment, when the input signal is polar coordinate data including amplitude data and phase data, amplitude data is input to the data conversion unit. In this case, the modulation amplification unit includes an angle modulation unit, an amplitude modulation unit, and a voltage control unit. The angle modulation unit outputs an angle-modulated wave signal by angle-modulating the phase data. The amplitude modulation unit amplitude-modulates the angle-modulated wave signal with a voltage corresponding to the magnitude of the signal output from the data conversion unit. The voltage control unit controls the voltage supplied to the amplitude modulation unit according to the magnitude of the signal output from the data conversion unit.

  As another embodiment, the transmission circuit of the present invention can be configured to include a data conversion unit and a modulation amplification unit. The data converter receives a part of the input signal, performs predetermined data conversion on the input signal, and outputs it. The modulation amplification unit outputs a transmission signal by performing at least one of modulation and amplification based on the signal converted by the data conversion unit. More specifically, the data converter receives a modulated wave signal and amplitude data that are scalar data. The data conversion unit includes a signal processing unit, a first subtraction unit, a filter, and a second subtraction unit.

  The signal processing unit discretizes the input signal and generates a signal having a resolution lower than that of the input signal. The first subtracting unit subtracts the input signal from the low resolution signal generated by the signal processing unit, and extracts the quantization noise component generated in the signal processing unit. The filter band-limits the quantization noise component extracted by the first subtraction unit with a predetermined cut-off frequency, and extracts a quantization noise component near the desired wave frequency that is the center frequency of the input signal. The second subtracting unit subtracts the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low-resolution signal generated by the signal processing unit, thereby resolving the resolution with respect to the magnitude of the input signal. A signal obtained by removing the quantization noise component in the vicinity of the desired wave from the low signal is output.

  Polar coordinate data including amplitude data and phase data is input to the transmission circuit. In this case, amplitude data is input to the data converter. The modulation amplification unit includes a voltage control unit, a low-pass filter, an angle modulation unit, and an amplitude modulation unit. The voltage control unit controls the output voltage according to the signal converted by the data conversion unit. The low pass filter band-limits the voltage controlled by the voltage control unit with a predetermined cut-off frequency, and removes noise components outside the band. The angle modulation unit outputs an angle-modulated wave signal by angle-modulating the phase data. The amplitude modulation unit amplitude-modulates the angle-modulated wave signal with the voltage output by the low-pass filter.

  A signal processing unit used for a data conversion unit to which orthogonal data is input includes a coordinate system conversion unit, a delta-sigma modulator, and a multiplication unit. The coordinate conversion unit generates amplitude data indicating the size of the orthogonal data, divides the amplitude data from the orthogonal data, and generates phase data, thereby converting the orthogonal data into coordinate data and amplitude data. The delta sigma modulator performs delta sigma modulation on the amplitude data to a binary value or more, thereby reducing the resolution of the amplitude data. The multiplication unit multiplies the amplitude data that has been delta-sigma modulated by the delta-sigma modulator and the phase data, and outputs a signal having a resolution lower than that of the orthogonal data.

  In addition, the signal processing unit used in the data conversion unit to which orthogonal data is input may be configured to include at least one subtraction unit, at least one vector integration unit, and a vector quantization unit. Orthogonal data is input to the subtraction unit. The vector integration unit is connected to the subtraction unit and integrates each element of the orthogonal data. The vector quantization unit uses at least two or more discrete values for the orthogonal data integrated by the vector integration unit, and the maximum discrete value whose integrated orthogonal data size is smaller than the input orthogonal data size. The signal is quantized so that the phase of the integrated orthogonal data becomes equal to the phase of the input orthogonal data, and a signal having a resolution lower than that of the input orthogonal data is output. The subtraction unit subtracts the orthogonal data quantized by the vector quantization unit from the input orthogonal data.

  A signal processing unit used in a data conversion unit to which a modulated wave signal or amplitude data that is scalar data is input includes a delta-sigma modulator. The delta-sigma modulator outputs a signal having a lower resolution than the input signal by performing delta-sigma modulation on the input signal to two or more values.

  For example, when the zero point of the noise transfer function in the signal processing unit is 1, the filter included in the data conversion unit is a low-pass filter.

For example, when the zero point of the noise transfer function in the signal processing unit is a complex number of size 1, the filter included in the data conversion unit is a bandpass filter.
Further, for example, when the pole of the delta-sigma modulator is a complex number of size 1, the filter included in the data converter is a bandpass filter.

  When the filter is a low-pass filter, the cutoff frequency of the filter included in the data conversion unit is preferably smaller than ½ of the sampling frequency in the signal processing unit. In addition, when the filter is a bandpass type, the cutoff frequency of the filter included in the data converter is larger than the frequency obtained by subtracting 1/2 of the sampling frequency from the center frequency of the input signal, It is preferably smaller than the frequency obtained by adding 1/2 of the sampling frequency to the center frequency.

  The present invention is also directed to communication devices and electronic devices. And in order to achieve the said objective, the communication apparatus of this invention is equipped with all the transmission circuits as described above, and the antenna which outputs the transmission signal produced | generated by the transmission circuit.

  The electronic device of the present invention includes an amplifier and a data conversion unit that converts an input signal into a signal to be input to the amplifier and outputs the signal. The data conversion unit includes a first subtraction unit, a filter, and a second subtraction unit. The first subtracting unit discretizes the input signal to generate a signal having a resolution lower than the input signal, and subtracts the input signal from the low resolution signal generated by the signal processing unit. Then, the quantization noise component generated in the signal processing unit is extracted. The filter band-limits the quantization noise component extracted by the first subtraction unit with a predetermined cut-off frequency, and extracts a quantization noise component near the desired wave frequency that is the center frequency of the input signal. The second subtraction unit subtracts the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low resolution signal generated by the signal processing unit, so that the resolution is lower than the input signal. A signal from which the quantization noise component near the desired wave frequency is removed from the signal is output.

  The present invention is also directed to a data conversion method for performing predetermined data conversion on an input signal and outputting it. In order to achieve the above object, the data conversion method of the present invention discretizes an input signal, generates a signal having a resolution lower than that of the input signal, and inputs the signal from a signal having a low resolution. The quantization noise component generated during quantization is extracted by subtracting the signal to be quantized, and the extracted quantization noise component is band-limited with a predetermined cut-off frequency to the vicinity of the desired wave frequency that is the center frequency of the input signal Quantization noise near the desired wave frequency from the signal with lower resolution than the input signal by subtracting the quantization noise component near the desired wave from the low resolution signal Data conversion is performed on the signal from which the components have been removed.

  As described above, in the present invention, the data conversion unit, after quantizing the input signal, removes quantization noise generated during quantization from the vicinity of the desired wave frequency. Therefore, it is possible to output a signal with reduced quantization noise near the desired wave frequency without troublesome control. Further, it is not necessary to increase the clock frequency or the order of the delta sigma modulator to reduce the quantization noise near the desired wave frequency, so that the power consumption for this can be reduced.

  In addition, the transmission circuit does not need to use a band pass filter having a steep attenuation characteristic by reducing quantization noise in the vicinity of the desired wave frequency. Therefore, the power consumption of the entire transmission circuit can be reduced. Further, even if the frequency band of the transmission signal changes, it is not necessary to change the pass band of the bandpass filter, so that power consumption for this can be reduced and the circuit scale can be reduced.

(First embodiment)
FIG. 1 is a block diagram showing a configuration example of a transmission circuit 1 according to the first embodiment of the present invention. In FIG. 1, the transmission circuit 1 includes an input terminal 11, an output terminal 12, a data conversion unit 13, a vector modulation unit 14, an amplifier 15, and a bandpass filter 16.

  The data converter 13 performs predetermined data conversion on the input signal and outputs it. The vector modulation unit 14 modulates the signal converted by the data conversion unit 13. The amplifier 15 amplifies the signal modulated by the vector modulation unit 14. The band pass filter 16 passes a signal in a desired frequency band from the signal amplified by the amplifier 15. Note that the vector modulation unit 14 and the amplifier 15 constitute a modulation amplification unit.

Hereinafter, the operation of the transmission circuit 1 will be described.
A baseband signal is input to the input terminal 11 as an input signal. Here, I data and Q data represented by vectors orthogonal to each other are input as baseband signals. Hereinafter, data represented by an orthogonal coordinate system such as I data and Q data is referred to as orthogonal data. Note that the orthogonal data that is the input signal may be a digital signal represented by multiple bits (that is, a signal that has already been discretized) or an analog signal (a signal that has not been discretized). Shall.

  The orthogonal data is input to the data conversion unit 13 via the input terminal 11. The data converter 13 converts the orthogonal data, which is an input signal, into a signal having a lower resolution than the input signal. Specifically, when the input signal is a discretized signal, the data conversion unit 13 widens the interval between the discrete values, thereby converting the orthogonal data that is the input signal into a signal having a lower resolution than the input signal. Convert. When the input signal is a signal that has not been discretized, the data converter 13 discretizes the input signal, thereby converting the orthogonal data that is the input signal into a signal having a lower resolution than the input signal. Hereinafter, the term “discretization” means both widening the interval between discrete values of a discretized signal and discretizing an undiscretized signal.

  In the data conversion unit 13, noise components other than the desired wave frequency, such as quantization noise, are generated with the discretization of the input signal. Therefore, the data converter 13 removes the quantization noise from the vicinity of the desired wave frequency, and outputs a signal in which the quantization noise is reduced in the vicinity of the desired wave frequency. The data converter 13 will be described later with a specific configuration.

  FIG. 2 is a diagram illustrating a waveform example of the magnitude of the signal output from the data converter 13 (the square root of the square sum of the output I data and Q data). However, the data conversion unit 13 discretizes the input signal to separate the input signal into two regions (for example, roughly two regions represented by 0 and a real number). In this case, the magnitude of the signal output from the data converter 13 is such that the output is switched on / off as shown in FIG. As described above, the data converter 13 is not completely discretized with respect to the size, but can output a signal having only two on / off states and having a small level fluctuation in each state.

  The signal output from the data conversion unit 13 is input to the vector modulation unit 14. The vector modulation unit 14 modulates the signal output from the data conversion unit 13 and outputs a modulated wave signal. FIG. 3 is a diagram illustrating a waveform example of a signal output from the vector modulation unit 14. As shown in FIG. 3, the vector modulation unit 14 can output a signal having a small envelope variation in the on and off states. For example, the vector modulation unit 14 outputs a modulated wave signal by orthogonally modulating the input signal.

  2 and 3, the reason why the envelope of the signal waveform is not constant (perfect straight line) is that a part of the quantization noise is removed in the data conversion unit 13.

  The modulated wave signal output from the vector modulation unit 14 is input to the amplifier 15. The amplifier 15 amplifies the modulated wave signal to a necessary output level and outputs it. FIG. 4 is a diagram illustrating characteristics of a general amplifier.

  Referring to FIG. 4, the amplifier 15 has a small variation in the envelope when the input signal (modulated wave signal) is in an ON state. A signal having a small change range of instantaneous input power is not easily affected by distortion even in the nonlinear region of the amplifier 15. Therefore, the amplifier 15 can output a signal with small distortion even in the nonlinear region. Further, it can be seen from FIG. 4 that the amount of change in output power with respect to the change in input power is small. This also shows that the amplifier 15 is less affected by distortion of the output power due to the change of the input power.

  The modulated wave signal amplified by the amplifier 15 is input to the band pass filter 16. The band pass filter 16 removes unnecessary noise components outside the band from the input modulated wave signal and outputs a desired modulated wave signal.

  The band pass filter 16 is not required to have a steep attenuation characteristic because the data converter 13 has already removed the quantization noise in the vicinity of the desired wave frequency. Further, since the bandpass fill 16 can widen the passband if the quantization noise in the transmission band is sufficiently removed, it is not necessary to change the passband even if the frequency of the transmission signal changes. FIG. 5 is a diagram illustrating an example of characteristics required for the band-pass filter 16 in the transmission circuit 1 according to the first embodiment of the present invention. For example, the bandpass filter 907 in the conventional transmission circuit shown in FIG. 30 changes the passband as A to D, but the bandpass filter 16 in this embodiment changes the passband in this way. There is no need to let them.

Next, a specific configuration of the data conversion unit 13 will be described.
FIG. 6 is a block diagram illustrating a configuration example of the data conversion unit 13 according to the first embodiment of the present invention. 6, the data conversion unit 13 includes an input terminal 131, an output terminal 132, a signal processing unit 133, a subtraction unit 134, a filter 135, and a subtraction unit 136.

  In FIG. 6, I data and Q data are input to the input terminal 131 as baseband signals. The I data and Q data are input to the signal processing unit 133 and the subtraction unit 134.

  FIG. 7 is a diagram illustrating an example of a spectrum of a signal input to the signal processing unit 133 and the subtraction unit 134. In FIG. 7, the frequency on the horizontal axis represents a deviation from the center frequency (desired wave frequency) of the input signal. FIG. 8 is a diagram showing the existence probability of the square sum of the vector data included in the input signal of FIG. Each waveform example shown in the description of the data conversion unit 13 is a signal modulated by 16QAM as a primary modulation, a symbol rate of 20 MHz, OFDM as a secondary modulation, and an FFT length of 64. The data conversion unit 13 in FIG. It is an example of a waveform when it inputs from the input terminal 131.

  In FIG. 6, the signal processing unit 133 discretizes orthogonal data that is an input signal, and outputs a signal having a resolution lower than that of the input signal in terms of size. The signal processing unit 133 performs sampling at a high speed when discretizing the input signal. For example, the signal processor 133 may perform oversampling several tens to several thousand times. By performing such oversampling, the signal processor 133 improves the SN ratio of the output signal. can do. The signal processing unit 133 will be described later with a specific configuration example.

  FIG. 9 is a diagram illustrating an example of a spectrum of a signal output from the signal processing unit 133. FIG. 10 is a diagram showing the existence probability of the square sum of the vector data included in the signal of FIG. However, the signal processing unit 133 sets the clock frequency to 640 MHz, which is 32 times the symbol rate, and discretizes the input signal into binary values. As shown in FIG. 9, the signal output from the signal processing unit 133 includes a high level of quantization noise generated with discretization up to the vicinity of the desired wave frequency (center frequency).

  Also, in FIG. 10, the existence probability of the sum of squares of vector data is clearly discretized into a vector data size of 0 or a constant as compared with FIG. In FIG. 10, the existence probability of the sum of squares of vector data seems to have a peak at minus 20 dB. However, for the convenience of display, the existence probability from minus infinity dB to minus 20 dB is integrated. Represents. However, it is actually known that the presence is concentrated in minus infinity dB.

The signal output from the signal processing unit 133 is input to the subtraction unit 134 and the subtraction unit 136. The subtracting unit 134 subtracts I data and Q data, which are input signals, from the signals I ₂ and Q ₂ output by the signal processing unit 133, and outputs a signal indicated by Ie and Qe. That is, the outputs Ie and Qe of the subtracting unit 134 can be expressed by Expression (1) and Expression (2), where I data and Q data as input signals are I and Q, respectively.
Ie = I ₂ −I (1)
Qe = Q ₂ -Q (2)

  FIG. 11 is a diagram illustrating an example of a spectrum of a signal output from the subtraction unit 134. The signals Ie and Qe output from the subtraction unit 134 are obtained by subtracting the input signal from the signal output by the signal processing unit 133. Therefore, the signals Ie and Qe output from the subtracting unit 134 are quantization noise generated by the signal processing unit 133.

The quantization noises Ie and Qe output from the subtraction unit 134 are input to the filter 135. The filter 135 limits the quantization noise with a predetermined cutoff frequency and outputs signals Ie ₂ and Qe ₂ . The signals Ie ₂ and Qe ₂ output from the filter 135 are input to the subtraction unit 136.
FIG. 12 is a diagram illustrating an example of a spectrum of a signal output from the filter 135. However, it is assumed that the filter 135 is a low-pass filter having a cutoff frequency of 80 MHz. In FIG. 12, the signal output from the filter 135 represents quantization noise near the desired wave frequency.

The subtracting unit 136 receives an output signal from the signal processing unit 133 (a signal including quantization noise) and an output signal from the filter 135 (a quantization noise near the desired wave frequency). The subtracting unit 136 subtracts the output signal of the filter 135 from the output signal of the signal processing unit 133. FIG. 13 is a diagram illustrating an example of a spectrum of a signal output from the subtraction unit 136. As shown in FIG. 13, the subtraction unit 136 outputs a signal in which the quantization noise near the desired wave frequency is reduced. The output signals It and Qt of the subtracting unit 136 can be expressed by equations (3) and (4).
It = I ₂ −Ie ₂ (3)
Qt = Q ₂ −Qe ₂ (4)

  FIG. 14 is a diagram showing the existence probability of the sum of squares of the vector data included in the signal of FIG. In FIG. 14, the existence probability of the square sum of the vector data is not completely discretized, but it can be confirmed that the dynamic range is significantly narrower than that in FIG. For this reason, in the transmission circuit 1 of FIG. 1, the vector modulation unit 14 and the amplifier 15 that handle the signal output from the data conversion unit 13 need only ensure the operation in this narrow range. In FIG. 14, the existence probability of the sum of squares of the vector data seems to have a peak at minus 20 dB, but for the convenience of display, the existence probability from minus infinity dB to minus 20 dB is integrated. Represents.

  Next, the signal processing unit 133 will be described with reference to two specific configuration examples (FIGS. 15 and 16).

First, the signal processing unit 133 will be described using a first configuration example.
FIG. 15 is a block diagram illustrating a first configuration example of the signal processing unit 133. In FIG. 15, the signal processing unit 133 includes an input terminal 1331, an output terminal 1332, a coordinate system conversion unit 1333, a delta sigma modulator 1334, and a multiplication unit 1335.

In FIG. 15, I data and Q data are input to the input terminal 1331 as baseband signals. The I data and Q data are input to the coordinate system conversion unit 1333. The coordinate system conversion unit 1333 converts the I data and Q data, which are orthogonal data, into polar coordinate system data represented by amplitude data and phase data. Hereinafter, polar coordinate system data represented by amplitude data and phase data is referred to as polar coordinate data.
That is, the coordinate system conversion unit 1333 outputs the amplitude data M and the phase data Ip and Qp. The phase data Ip and Qp represent the phase data in an orthogonal coordinate system. The relationship between the amplitude data M and the phase data Ip and Qp can be expressed by Expression (5), Expression (6), and Expression (7), where I and Q are the input baseband signals.
M = (I ² + Q ² ) ^1/2 (5)
Ip = I / M (6)
Qp = Q / M (7)

  The amplitude data M output from the coordinate system conversion unit 1333 is input to the delta sigma modulator 1334. The delta sigma modulator 1334 outputs a signal obtained by reducing the resolution of the amplitude data M by performing delta sigma modulation on the amplitude data M as the delta sigma modulation signal Md. The delta sigma modulation signal Md is input to the multiplication unit 1335. Here, the delta sigma modulator 1334 may perform primary delta sigma modulation or secondary delta sigma modulation. The delta-sigma modulator 1334 can reduce the quantization noise near the desired wave frequency as the higher-order delta-sigma modulation is performed.

On the other hand, the phase data Ip and Qp output from the coordinate system conversion unit 1333 are input to the multiplication unit 1335. The multiplication unit 1335 multiplies the phase data Ip and Qp by the delta sigma modulation signal Md output from the delta sigma modulator 1334, and outputs quadrature data I ₂ and Q ₂ . The signals I ₂ and Q ₂ output from the multiplication unit 1335 can be expressed by Expression (8) and Expression (9). The output terminal 1332 outputs the signals I ₂ and Q ₂ expressed by the equations (8) and (9).
I ₂ = Md · Ip (8)
Q ₂ = Md · Qp (9)

  Thus, since the signal processing unit 133 according to the first configuration example outputs the input signal after delta-sigma modulation, it can output a signal whose resolution is smaller than that of the input signal.

Next, the signal processing unit 133 will be described using a second configuration example.
FIG. 16 is a block diagram illustrating a second configuration example of the signal processing unit 133. In FIG. 16, the signal processing unit 133 includes an input terminal 1331, an output terminal 1332, a subtraction unit 1336, a vector integration unit 1337, and a vector quantization unit 1338.

  In FIG. 16, I data and Q data are input to the input terminal 1331 as baseband signals. The I data and Q data are input to the vector integration unit 1337 via the subtraction unit 1336. The vector integration unit 1337 integrates each of the I data and Q data by vector calculation, and outputs integrated signals Iv and Qv. That is, when the orthogonal data string input to the vector integration unit 1337 is (Ii, Qi), the vector integration unit 1337 outputs (Iv, Qv) = (ΣIi, ΣQi). The signals Iv and Qv output from the vector integration unit 1337 are input to the vector quantization unit 1338.

The vector quantization unit 1338 quantizes the input signals Iv and Qv and outputs signals I ₃ and Q ₃ . I ₃ and Q ₃ can be represented by Formula (10) and Formula (11), or Formula (12) and Formula (13). Here, a is a constant. It is assumed that vector quantization section 1338 performs quantization with a binary value for the magnitude of the input signal. Specifically, the vector quantization unit 1338 generates a signal whose magnitude is a and whose phase is equal to that of the input signal when the magnitude (Iv ² + Qv ² ) ^1/2 of the input signal is equal to or greater than a predetermined threshold value a. When the magnitude of the input signal is less than the predetermined threshold value a, a zero vector is output. Also, the subtraction unit 1336 subtracts the output of the vector quantization unit 1338 from the input data and outputs the result to the vector integration unit 1337.
When (Iv ² + Qv ² ) ^1/2 ≧ a I ₃ = a · Iv / (Iv ² + Qv ² ) ^1/2 (10)
Q ₃ = a · Qv / (Iv ² + Qv ² ) ^1/2 (11)
When (Iv ² + Qv ² ) ^1/2 <a I ₃ = 0 (12)
Q ₃ = 0 (13)

  Thus, since the signal processing unit 133 according to the second configuration example outputs the input signal after vector integration and quantization, it can output a signal whose resolution is smaller than that of the input signal.

  In FIG. 6, the cutoff frequency of the filter 135 in the data conversion unit 13 is smaller than ½ of the clock frequency of the delta-sigma modulator 1334 and the vector quantum unit 1338 in FIGS. 15 and 16 according to the Nyquist definition. It is desirable.

  In FIG. 15, the signal processing unit 133 according to the first configuration example uses the delta sigma modulator 1334. However, if the modulator can discretize the input signal, the delta sigma modulator is used. It is not limited to. For example, the signal processing unit 133 may use a delta modulator or a pulse width modulator (PWM) instead of the delta sigma modulator 1334.

  Note that the signal processing unit 133 according to the second configuration example may have a higher-order configuration using a plurality of subtraction units 1336 and vector integration units 1337 (see FIGS. 17 and 18). The signal processing unit 133 according to the second configuration example can further reduce the quantization noise in the vicinity of the desired wave frequency by adopting such a high-order configuration.

  As described above, the data conversion unit 13 according to the first embodiment discretizes the input signal and converts it to a signal having a resolution lower than that of the input signal, and then converts the quantization noise generated by the discretization to a desired wave. Remove from the vicinity of the frequency. Therefore, the data conversion unit can output a signal with reduced quantization noise in the vicinity of the desired wave frequency without troublesome control. In addition, the data converter 13 does not need to increase the clock frequency or the order of the delta-sigma modulator to reduce the quantization noise near the desired wave frequency, so that it is possible to reduce power consumption for this purpose.

  In addition, the transmission circuit according to the present embodiment eliminates the need for using a band-pass filter having a steep attenuation characteristic by reducing quantization noise near the desired wave frequency. Therefore, the power consumption of the entire transmission circuit can be reduced. Further, even if the frequency band of the transmission signal changes, it is not necessary to change the pass band of the bandpass filter, so that power consumption for this can be reduced and the circuit scale can be reduced.

(Second Embodiment)
FIG. 19 is a block diagram illustrating a configuration example of the transmission circuit 1 according to the second embodiment of the present invention. The transmission circuit 1 according to the present embodiment is different from the first embodiment (FIG. 1) in the configuration (modulation amplification unit) for modulating or amplifying the signal output from the data conversion unit. Note that the transmission circuit according to the second embodiment outputs a transmission signal by polar-modulating the signal output from the data conversion unit. Therefore, the data conversion unit is the same as in the first embodiment. Only the parts different from the first embodiment will be described below.

  19, the transmission circuit 1 includes an input terminal 11, an output terminal 12, a data conversion unit 13, a polar coordinate system conversion unit 17, an angle modulation unit 18, an amplitude modulation unit 19, a voltage control unit 21, and a bandpass filter 16. .

  The polar coordinate system conversion unit 17 converts the input orthogonal data into amplitude data and phase data that are polar coordinate data. The angle modulation unit 18 angle-modulates the phase data. The voltage control unit 21 supplies a voltage controlled according to the amplitude data to the amplitude modulation unit 19. The amplitude modulator 19 amplitude-modulates the signal angle-modulated by the angle modulator 18 with a voltage controlled according to the amplitude data. The data conversion unit 13 and the band pass filter 16 are the same as those in the first embodiment. The polar coordinate conversion unit 17, the angle modulation unit 18, the amplitude modulation unit 19, and the voltage control unit 21 constitute a modulation amplification unit.

Hereinafter, the operation of the transmission circuit 1 will be described.
In FIG. 19, the operation until the data converter 13 outputs a signal is the same as that in the first embodiment. The signal output from the data conversion unit 13 is input to the polar coordinate system conversion unit 17. The polar coordinate system conversion unit 17 converts an input signal that is orthogonal data into a signal that is a polar coordinate system and outputs the signal. That is, the polar coordinate system conversion unit 17 converts the coordinates of the input signal and outputs amplitude data composed of amplitude components and phase data composed of phase components. The amplitude data output from the polar coordinate system conversion unit 17 is a signal such that the output is switched on / off when the data conversion unit 13 quantizes the input signal with 1 bit (binary value of 0 and real number). It becomes. In other words, the polar coordinate system conversion unit 17 can output a signal that is not completely discretized with respect to the size, but has only two states where the envelope is on / off, and the variation of the envelope in each state is small. . Therefore, the signal output from the polar coordinate system conversion unit 17 is not easily affected by the nonlinearity of the amplitude modulation unit 19.

  The phase data is input to the angle modulation unit 18. The angle modulation unit 18 angle-modulates the input phase data and outputs an angle-modulated wave signal. The angle modulation wave signal is input to the amplitude modulation unit 19. On the other hand, the amplitude data output from the polar coordinate system conversion unit 17 is input to the voltage control unit 21. The voltage control unit 21 supplies a voltage controlled according to the amplitude data to the amplitude modulation unit 19. The amplitude modulator 19 outputs a modulated wave signal by amplitude-modulating the angle-modulated wave signal output from the angle modulator 18 with a voltage controlled according to the amplitude data.

  The modulated wave signal output from the amplitude modulation unit 19 is input to the band pass filter 16. The band pass filter 16 removes unnecessary quantization noise components outside the band from the input modulated wave signal and outputs a desired modulated wave signal.

  For example, a series regulator or a switching regulator can be applied to the voltage control unit 21. FIG. 20 is a block diagram illustrating an example of the configuration of the voltage control unit 21 to which the series regulator is applied. In FIG. 20, the voltage control unit 21 includes an input terminal 211, a power supply 212, an output terminal 213, a comparison unit 214, and a transistor 215.

  In FIG. 20, amplitude data is input to the input terminal 211. The amplitude data is input to the gate or base of the transistor 215 through the comparison unit 214. That is, a voltage corresponding to the amplitude data is applied to the gate or base of the transistor 215. A voltage is applied from the power supply 212 to the drain or collector of the transistor 215. Therefore, a voltage controlled according to the amplitude data is output from the source or emitter of the transistor 215. Note that the voltage control unit 21 may feed back the voltage output from the source or emitter of the transistor 215 to the comparison unit 214 in order to stabilize the output. The voltage controlled according to the amplitude data is supplied to the amplitude modulation unit 19 via the output terminal 213.

  FIG. 21 is a block diagram illustrating an example of the configuration of the voltage control unit 21 to which the switching regulator is applied. The voltage control unit 21 includes an input terminal 211, a pulse conversion unit 216, an amplifier 217, a low pass filter 218, and an output terminal 213.

  In FIG. 21, amplitude data is input to the input terminal 211. The amplitude data is converted into a pulse signal by the pulse converter 216. As a conversion method in the pulse conversion unit 216, for example, PWM, delta-sigma modulation, or the like is used. The signal converted into the pulse is amplified by the amplifier 217 and sent to the low-pass filter 218. From the amplified pulse signal, a spurious signal having a clock frequency or a switching frequency generated at the time of pulse generation is removed by a low-pass filter 218 and output from an output terminal 213. That is, the voltage whose output level is controlled by the amplitude data is supplied to the amplitude modulator 19. The voltage control unit 21 may feed back the output of the low-pass filter 218 to the pulse conversion unit 216 in order to stabilize the output.

  As described above, also in the transmission circuit 1 according to the second embodiment of the present invention, the data conversion unit outputs a signal with reduced quantization noise near the desired wave frequency. Therefore, the transmission circuit 1 according to the present embodiment can obtain the same effects as the transmission circuit 1 according to the first embodiment.

(Third embodiment)
FIG. 22 is a block diagram illustrating a configuration example of the transmission circuit 1 according to the third embodiment of the present invention. The transmission circuit 1 according to the present embodiment is different from the transmission circuit 1 according to the first embodiment (FIG. 1) in that the vector modulation unit 34 is arranged before the data conversion unit 33. Therefore, not the I data and the Q data but the signal already modulated by the vector modulation unit 34 (modulated wave signal) is input to the data conversion unit 33. That is, the data conversion unit 33 according to the present embodiment processes a modulated wave signal that is scalar data, whereas the data conversion unit 13 according to the first embodiment processes orthogonal data that is vector data.

  In FIG. 22, the transmission circuit 1 includes an input terminal 11, an output terminal 12, a vector modulation unit 34, a data conversion unit 33, an amplifier 15, and a band pass filter 16.

  The data converter 33 performs predetermined data conversion on the input signal, which is a modulated wave signal, and outputs the result. The vector modulation unit 34, the amplifier 15, and the band pass filter 16 have the same configuration as that of the transmission circuit 1 (FIG. 1) according to the first embodiment. In the transmission circuit 1, the vector modulation unit 34 is not an essential configuration. This is because the present invention is characterized by the configuration of the data converter 33 and the transmission circuit 1 that handles the output signal of the data converter 33. In the case where the transmission circuit 1 does not include the vector modulation unit 34, a signal (modulated wave signal) that has already been modulated is input to the data conversion unit 33. The amplifier 15 constitutes a modulation amplification unit.

Hereinafter, the operation of the transmission circuit 1 will be described.
The input terminal 11 receives I data and Q data, which are orthogonal data. The I data and Q data are input to the vector modulation unit 34. The vector modulation unit 34 modulates the input I data and Q data, and outputs a modulated wave signal. For example, the vector modulation unit 34 outputs a modulated wave signal by orthogonally modulating the input signal. The modulated wave signal output from the vector modulation unit 34 is input to the data conversion unit 33. That is, an already modulated signal (modulated wave signal) is input to the data converter 33. The modulated wave signal input to the data conversion unit 33 may be a digital signal expressed in multiple bits (that is, a signal that has already been discretized) or an analog signal (a signal that has not been discretized). It may be.

  The data converter 33 discretizes the modulated wave signal (input signal) and converts it into a signal having a resolution lower than that of the input signal. Next, the data converter 33 removes the quantization noise from the vicinity of the desired wave frequency of the signal having a low resolution with respect to the magnitude and outputs the result. FIG. 23 is a diagram illustrating a waveform example of the output signal when the data conversion unit 33 according to the third embodiment of the present invention discretizes the input signal into binary values. As shown in FIG. 23, the data conversion unit 33 can output a signal that is not completely discretized but has little fluctuation in the envelope at the peak. In FIG. 23, the reason that the envelope at the peak does not become constant (perfect straight line) is that a part of the quantization noise is removed in the data conversion unit 33.

  The signal output from the data converter 33 is input to the amplifier 15. The amplifier 15 amplifies the input signal to a necessary output level and outputs it. The signal output from the amplifier 15 is input to the band pass filter 16. The bandpass filter 16 removes unnecessary components outside the band from the input signal and outputs a desired signal.

  FIG. 24 is a block diagram illustrating a configuration example of the data conversion unit 33 according to the third embodiment of the present invention. The data conversion unit 33 includes a signal processing unit 333, a subtraction unit 134, a filter 135, and a subtraction unit 136. The signal processing unit 333 discretizes the input signal and outputs it. The signal processing unit 333 is configured using, for example, a delta sigma modulator. The subtraction unit 134, the filter 135, and the subtraction unit 136 have the same configuration as that of the data conversion unit 13 according to the first embodiment.

  A modulated wave signal is input to the signal processing unit 333. The signal processing unit 333 outputs a signal having a resolution lower than that of the input signal by performing delta sigma modulation on the input signal (modulation wave signal) with a delta sigma modulator. The operation after the signal processing unit 333 outputs a signal is the same as that of the data conversion unit 13 according to the first embodiment.

  In FIG. 24, the cutoff frequency of the filter 135 in the data converter 33 is the clock frequency of the delta-sigma modulator in the signal processor 333 (that is, the sampling frequency) when the low-pass filter is used as the filter 135. It is desirable to be smaller than 1/2 of the frequency. When a bandpass filter is used as the filter 135, the cutoff frequency of the filter 135 is higher than the frequency obtained by subtracting 1/2 of the sampling frequency from the center frequency of the input signal, and the center frequency of the input signal. It is desirable that the frequency be smaller than the frequency obtained by adding 1/2 of the sampling frequency to the sampling frequency.

  In addition, the data conversion unit 33 according to the third embodiment has a feature between the signal processing unit 333 and the filter 135. In FIG. 24, the spectrum of the quantization noise signal generated by the signal processing unit 333 varies depending on the characteristics of the signal processing unit 333. Therefore, the data conversion unit 33 changes the type of the filter 135 by the signal processing unit 333.

In the signal processing unit 333, the output signal y (z) includes an input signal x (z), an input signal transfer function H1 (z), a quantization noise signal generated at the time of quantization e (z), Assuming that the noise transfer function is H2 (z), it is expressed by equation (14).
y (z) = H1 (z) .x (z) + H2 (z) .e (z) (14)

  From Expression (14), it can be seen that the quantized noise signal H2 (z) · e (z) output from the signal processing unit 333 is input to the filter 135. The spectrum of the quantized noise signal H2 (z) · e (z) varies depending on the position of the zero point of the noise transfer function H2 (z). Therefore, the data conversion unit 33 changes the type of the filter 135 that reduces the quantization noise signal H2 (z) · e (z) according to the position of the zero point of the noise transfer function H2 (z) in the signal processing unit 333.

The spectrum that changes depending on the position of the zero point of the noise transfer function is disclosed in Non-Patent Document 1, for example. FIG. 25 is a diagram illustrating the position of the zero point in the noise transfer function in which the zero is 1. FIG. 26 is a diagram illustrating an example of a spectrum of a signal output from the signal processing unit 333 in which the zero point of the noise transfer function is 1. As shown in FIG. 26, the signal output from the signal processing unit 333 whose noise transfer function zero is 1 has a direct current (0 Hz) frequency at which the quantization noise signal is minimized. That is, in FIG. 24, when the signal processing unit 333 whose noise transfer function zero is 1 is used, the filter 135 uses a low-pass filter to remove out-of-band quantization noise.
Note that such a signal processing unit 333 is configured using a low-pass delta sigma modulator when configured with a delta sigma modulator.

FIG. 27 is a diagram showing the position of the zero point of the noise transfer function in which the zero point is a complex number of size 1. In FIG. 27, the position of the zero point of the noise transfer function indicates a case where the magnitude is 1 and the declination is ± π / 4. FIG. 28 is a diagram illustrating an example of a spectrum of a signal output from the signal processing unit 333 in which the zero point of the noise transfer function is a complex number having a magnitude of 1. As shown in FIG. 28, the signal output from the signal processing unit 333 in which the zero point of the noise transfer function is a complex number of 1 is a standard in which the frequency at which the quantization noise is minimized is obtained by dividing the deviation angle of the zero point by 2π. Frequency. The signal processing unit 333 is designed so that the desired wave frequency is close to the frequency that minimizes the quantization noise.
That is, in FIG. 24, when the signal processing unit 333 in which the zero point of the noise transfer function is a complex number of size 1 is used, the filter 135 uses a bandpass filter to remove out-of-band quantization noise.
In addition, when such a signal processing unit 333 is configured by a delta sigma modulator, the signal processing unit 333 is configured by using a bandpass delta sigma modulator.

  The feature between the signal processing unit 333 and the filter 135 is not limited to the data conversion unit 33 (FIG. 24) to which scalar data is input, but can be applied to a data conversion unit to which vector data is input. it can. Therefore, the signal processing unit whose noise transfer function zero is 1 and the signal processing unit whose noise transfer function zero is a complex number of size 1 are the data conversion unit 13 in the first and second embodiments (FIG. 6). ). The reason will be described below.

In the data converter 13 (FIG. 6) to which vector data is input, the output signals I ₂ (z) and Q ₂ (z) are the input signals I (z) and Q (z), and the input signal is transmitted. When the functions are H1i (z) and H1q (z), the quantized noise signal is Ie (z) and Qe (z), and the noise transfer functions are H2i (z) and H2q (z), equations (15) and (16 ).
I ₂ (z) = H1i (z) · I (z) + H2i (z) · Ie (z) (15)
Q ₂ (z) = H1q (z) · Q (z) + H2q (z) · Qe (z) (16)

  The quantization noise signals H2i (z) · Ie (z) and H2q (z) · Qe (z) output from the signal processing unit 133 are input to the filter 135 according to the equations (15) and (16). I understand that The spectrum of this quantized noise signal changes according to the position of the zero point of the noise transfer functions H2i (z) and H2q (z), like the signal processing unit 333 to which scalar data is input. Therefore, the data conversion unit 13 can change the type of the filter 135 that reduces the quantization noise signal according to the position of the zero point of the noise transfer function in the signal processing unit 133.

  As described above, the data conversion unit according to the third embodiment can output a signal with reduced quantization noise near the desired wave frequency. Therefore, the data conversion unit can obtain the same effect as that of the first embodiment. In the transmission circuit according to the present embodiment, since the signal from which the quantization noise near the desired wave frequency is removed is input to the amplifier 15 and the bandpass filter 16, the same effect as that of the first embodiment is obtained. be able to.

(Fourth embodiment)
FIG. 29 is a block diagram illustrating a configuration example of the transmission circuit 1 according to the fourth embodiment of the present invention. In the transmission circuit 1 according to the present embodiment, the transmission circuit 1 according to the second embodiment (FIG. 19) processes orthogonal data in the data conversion unit 13, whereas the data conversion unit 43 is polar coordinate data. The difference is that the amplitude data is processed. Therefore, amplitude data is input to the data conversion unit 43 according to the present embodiment instead of I data and Q data which are orthogonal data. The data converter 43 according to the present embodiment is the same as the data converter 33 according to the third embodiment in that it processes scalar data.

  29, the transmission circuit 1 includes an output terminal 12, a data generation unit 20, a data conversion unit 43, an angle modulation unit 18, an amplitude modulation unit 19, a voltage control unit 21, and a band pass filter 16.

  The data generation unit 20 outputs amplitude data and phase data. The data converter 43 performs predetermined data conversion on the amplitude data and outputs the result. The angle modulation unit 18, the amplitude modulation unit 19, the voltage control unit 21, and the band pass filter 16 are the same as those in the second embodiment. The angle modulation unit 18, the amplitude modulation unit 19, and the voltage control unit 21 constitute a modulation amplification unit.

Hereinafter, the operation of the transmission circuit 1 will be described.
The data generation unit 20 outputs amplitude data and phase data based on the input I data and Q data (not shown). The data generation unit 20 is the same as the polar coordinate system conversion unit 17 described in the transmission circuit 1 (FIG. 19) according to the second embodiment in that it outputs amplitude data and phase data from I data and Q data. is there.

  In the transmission circuit 1, the data generation unit 20 is not an essential configuration. This is because the present invention is characterized by the configuration of the transmission circuit 1 that handles the output signal of the data converter 43. When the transmission circuit 1 is configured without the data generation unit 20, the amplitude data is directly input to the data conversion unit 43. Further, the phase data is directly input to the angle modulator 18.

  The amplitude data is input to the data conversion unit 43. The data converter 43 discretizes the input amplitude data and converts it into a signal having a resolution lower than that of the input amplitude data. In the data conversion unit 43, noise components other than the desired wave frequency, such as quantization noise, are generated with the discretization of the amplitude data. Therefore, the data converter 43 removes quantization noise from the vicinity of the desired wave frequency, and outputs a signal in which the quantization noise is reduced in the vicinity of the desired wave frequency.

  Note that the data converter 43 according to the present embodiment handles amplitude data that is scalar data, and therefore can have the same configuration as the data converter 33 of FIG. 24 according to the third embodiment.

  The signal output from the data conversion unit 43 is input to the voltage control unit 21. The voltage control unit 21 supplies a voltage controlled by the signal output from the data conversion unit 43 to the amplitude modulation unit 19. On the other hand, the phase data is input to the angle modulation unit 18. The angle modulation unit 18 angle-modulates the input phase data and outputs an angle-modulated wave signal. The angle modulation wave signal is input to the amplitude modulation unit 19.

  The amplitude modulation unit 19 modulates the amplitude of the angle-modulated wave signal with a voltage controlled by the signal output from the data conversion unit 13, and outputs a modulated wave signal. The modulated wave signal output from the amplitude modulation unit 19 is input to the band pass filter 16. The band pass filter 16 removes unnecessary quantization noise components outside the band from the input modulated wave signal and outputs a desired modulated wave signal.

  As described above, the data conversion unit according to the fourth embodiment can output a signal with reduced quantization noise near the desired wave frequency. Therefore, the data conversion unit can obtain the same effect as that of the first embodiment. In the transmission circuit according to the present embodiment, since the signal from which the quantization noise near the desired wave frequency is removed is input to the amplitude modulation unit 19 and the bandpass filter 16, the same effect as that of the first embodiment is obtained. Can be obtained.

(Fifth embodiment)
FIG. 30 is a block diagram showing a configuration example of the transmission circuit 1 according to the fifth embodiment of the present invention. The transmission circuit 1 according to the present embodiment is that the signal output from the data conversion unit 43 is input to the amplitude modulator 19 via the low-pass filter 22 in that the transmission circuit 1 according to the fourth embodiment (FIG. It is different from 29). The data conversion unit 43 according to the present embodiment is the same as that of the fourth embodiment.

  30, the transmission circuit 1 includes an output terminal 12, a data conversion unit 43, an angle modulation unit 18, an amplitude modulation unit 19, a data generation unit 20, a voltage control unit 21, and a low-pass filter 22.

  The low pass filter 22 removes a noise component from the voltage output from the voltage control unit 21. The data generation unit 20, the data conversion unit 43, the angle modulation unit 18, the amplitude modulation unit 19, and the voltage control unit 21 are the same as the configuration of the fourth embodiment. The angle modulation unit 18, the amplitude modulation unit 19, the voltage control unit 21, and the low-pass filter 22 constitute a modulation amplification unit.

Hereinafter, the operation of the transmission circuit 1 will be described.
Operations until the data conversion unit 43 and the angle modulation unit 18 output signals are the same as those of the transmission circuit 1 (FIG. 29) according to the fourth embodiment.

  The signal output from the data conversion unit 43 is input to the voltage control unit 21. The voltage control unit 21 supplies a voltage corresponding to the signal output from the data conversion unit 43 to the amplitude modulation unit 19 via the low-pass filter 22. For example, a high-efficiency amplifier is used for the voltage control unit 21. In this case, the voltage control unit 21 outputs the amplified amplitude data as the output voltage.

  The low-pass filter 22 removes unnecessary quantization noise components out of the band from the voltage supplied from the voltage control unit 21 to the amplitude modulation unit 19. That is, the voltage from which the quantization noise has been removed is applied to the amplitude modulator 19. Note that the low-pass filter 22 is not required to have a steep attenuation characteristic because the quantization noise is removed by the data conversion unit 43.

  On the other hand, the angle modulation wave signal output from the angle modulation unit 18 is input to the amplitude modulation unit 19. The amplitude modulation unit 19 amplitude-modulates the angle-modulated wave signal with the voltage supplied via the low-pass filter 22 and outputs the modulated wave signal. That is, the output terminal 12 outputs a desired modulated wave signal.

  As described above, the data conversion unit according to the fifth embodiment can output a signal with reduced quantization noise near the desired wave frequency. Therefore, the data conversion unit can obtain the same effect as that of the first embodiment. In the transmission circuit according to the present embodiment, since the signal from which the quantization noise near the desired wave frequency is removed is input to the voltage control unit 21, the low-pass filter 22, and the amplitude modulation unit 19, the first embodiment The same effect can be obtained.

(Sixth embodiment)
In the sixth embodiment, an electronic device such as an audio device or a video device to which the data conversion unit 33 according to the third embodiment is applied will be described. FIG. 31 is a block diagram showing an example of the configuration of an audio device to which the data conversion unit 33 of the present invention is applied. 31, the audio device includes a terminal 51, a data conversion unit 33, an amplification unit 52, a filter unit 53, and a speaker unit 54.

  In FIG. 31, audio data that is an input signal is input to the data converter 33 via a terminal 51. As in the third embodiment, the data conversion unit 33 discretizes audio data that is an input signal and converts the audio data into a signal having a resolution lower than that of the input signal. Next, the data conversion unit 33 removes quantization noise in the vicinity of the desired wave frequency from the signal having a low resolution with respect to the magnitude, and outputs a signal with reduced quantization noise. The amplification unit 52 amplifies the signal output from the data conversion unit 33. The signal amplified by the amplifying unit 52 is sent to the speaker unit 54 via the filter unit 53 and converted into sound. The filter unit 53 may be a low-pass filter when the delta-sigma modulator (see FIG. 24) in the data converter 33 is a low-pass type, and a band-pass filter when the band-pass type. As a result, an audio device in which quantization noise is suppressed and power consumption is reduced is provided.

  FIG. 32 is a block diagram showing an example of the configuration of a video equipment to which the data conversion unit 33 of the present invention is applied. 32, the video equipment includes a terminal 51, a data conversion unit 33, an amplification unit 52, a filter unit 53, and a display unit 55.

  In FIG. 32, video data that is an input signal is input to the data converter 33 via a terminal 51. As in the third embodiment, the data conversion unit 33 discretizes video data that is an input signal and converts the video data into a signal having a resolution lower than that of the input signal. Next, the data converter 33 removes quantization noise in the vicinity of the desired wave frequency from the signal having a low resolution with respect to the magnitude, and outputs a signal with reduced quantization noise. The amplification unit 52 amplifies the signal output from the data conversion unit 33. The signal amplified by the amplifying unit 52 is sent to the display unit 55 via the filter unit 53 and converted into video and / or audio. This provides a video device in which quantization noise is suppressed and power consumption is reduced.

  The original data conversion unit 33 can be applied to all electronic devices using an amplifier, and the applicable range is not limited to communication devices, audio devices, and video devices.

  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 example of a transmission circuit 1 according to a first embodiment of the present invention. The block diagram which shows the waveform example of the magnitude | size of the signal output from the data converter 13 The figure which shows the example of a waveform of the signal output from the vector modulation part 14 Diagram showing general amplifier characteristics The figure which shows an example of the characteristic calculated | required by the band pass filter 16 in the transmission circuit 1 which concerns on the 1st Embodiment of this invention. The block diagram which shows the structural example of the data converter 13 which concerns on the 1st Embodiment of this invention. The figure which shows an example of the spectrum of the signal input into the signal processing part 133 and the subtraction part 134 The figure which shows the existence probability of the square sum of the vector data contained in the input signal of FIG. The figure which shows an example of the spectrum of the signal output from the signal processing part 133 The figure which shows the existence probability of the square sum of the vector data contained in the signal of FIG. The figure which shows an example of the spectrum of the signal output from the subtraction part 134 The figure which shows an example of the spectrum of the signal output from the filter 135 The figure which shows an example of the spectrum of the signal output from the subtraction part 136 The figure which shows the existence probability of the square sum of the vector data contained in the signal of FIG. Block diagram showing a first configuration example of the signal processing unit 133 The block diagram which shows the 2nd structural example of the signal processing part 133 The block diagram which shows the structural example of the high-order signal processing part 133 The block diagram which shows the structural example of the high-order signal processing part 133 The block diagram which shows the structural example of the transmission circuit 1 which concerns on the 2nd Embodiment of this invention. The block diagram which shows an example of a structure of the voltage control part 21 to which the series regulator was applied The block diagram which shows an example of a structure of the voltage control part 21 to which the switching regulator was applied. The block diagram which shows the structural example of the transmission circuit 1 which concerns on the 3rd Embodiment of this invention. The figure which shows the example of a waveform of an output signal when the data conversion part 33 which concerns on the 3rd Embodiment of this invention discretizes an input signal into binary. The block diagram which shows the structural example of the data converter 33 which concerns on the 3rd Embodiment of this invention. The figure which shows the position of the zero in the noise transfer function where the zero is 1. The figure which shows an example of the spectrum of the signal output from the signal processing part 333 whose zero of a noise transfer function is 1 Diagram showing the position of the zero in the noise transfer function where the zero is a complex number of size 1. The figure which shows an example of the spectrum of the signal output from the signal processing part 333 whose zero of a noise transfer function is a complex number of magnitude 1 The block diagram which shows the structural example of the transmission circuit 1 which concerns on the 4th Embodiment of this invention. The block diagram which shows the structural example of the transmission circuit 1 which concerns on the 5th Embodiment of this invention. The block diagram which shows an example of a structure of the audio equipment to which the data conversion part 33 of this invention was applied. The block diagram which shows an example of a structure of the video equipment to which the data conversion part 33 of this invention was applied Block diagram showing an example of the configuration of a conventional communication device A block diagram showing an example of a configuration of a conventional transmission circuit 900 A block diagram showing an example of a configuration of a conventional transmission circuit 900 The figure which shows the example of a waveform of the modulation wave signal output from the amplitude modulation part 906 The figure which shows an example of the characteristic required for the band pass filter 907 in the conventional transmission circuit A block diagram showing an example of a configuration of a conventional transmission circuit 900

Explanation of symbols

11, 12, 51, 131, 132, 211, 213, 1331, 1332 Terminals 13, 33, 43, 912 Data converters 14, 34 Vector modulators 15, 52, 217, 906, 913, 925, 926 Amplifier 16, 22, 53, 135, 218, 907, 914 Filter 17 Polar coordinate system conversion unit 18, 904 Angle modulation unit 19, 905 Amplitude modulation unit 20 Data generation unit 21, 905 Voltage control unit 54 Speaker unit 55 Display unit 133 Signal processing unit 134 136, 1336 Subtraction unit 212 Power supply 214 Comparison unit 215 Transistor 216 Pulse conversion unit 1333 Coordinate system conversion unit 1334, 903 Delta-sigma modulator 1335 Multiplication unit 1337 Vector integration unit 1338 Vector quantization unit 900 Transmission circuit 901 Data generation unit 922 Signal Processing unit 9 3,924 signal source 927 synthesizer 951 receiving circuit 952 antenna duplexer 953 antenna unit

Claims (44)

A data conversion device that performs predetermined data conversion on an input signal and outputs the data,
A first arithmetic unit that discretizes the input signal and generates a signal having a resolution lower than that of the input signal;
A second arithmetic unit that extracts a quantization noise component generated in the first arithmetic unit from a low-resolution signal generated by the first arithmetic unit;
A third arithmetic unit that extracts a quantization noise component in the vicinity of a desired wave frequency that is a center frequency from the quantization noise component extracted by the second arithmetic unit;
Based on the low resolution signal generated by the first arithmetic unit and the quantization noise component in the vicinity of the desired wave frequency extracted by the third arithmetic unit, the magnitude of the signal is larger than the input signal. And a fourth arithmetic unit that outputs a signal obtained by removing a quantization noise component in the vicinity of a desired wave frequency from a signal with low resolution. The first arithmetic unit includes a signal processing unit that discretizes the input signal and generates a signal having a resolution lower than that of the input signal.
The second arithmetic unit subtracts the input signal from a low resolution signal generated by the signal processing unit, and extracts a quantization noise component generated in the signal processing unit. Part
The third arithmetic unit band-limits the quantization noise component extracted by the first subtraction unit with a predetermined cutoff frequency, and a quantum in the vicinity of a desired wave frequency that is a center frequency of the input signal. A filter for extracting the noise component,
The fourth arithmetic unit subtracts a quantization noise component in the vicinity of a desired wave frequency extracted by the filter from a low resolution signal generated by the signal processing unit, so that the input signal is more than the input signal. The data conversion apparatus according to claim 1, further comprising a second subtraction unit that outputs a signal obtained by removing a quantization noise component in the vicinity of a desired wave frequency from a signal having a low resolution with respect to the magnitude. The input signal is orthogonal data,
The signal processing unit
A coordinate conversion unit that generates amplitude data indicating the size of the orthogonal data, and generates the phase data by dividing the amplitude data from the orthogonal data, thereby converting the orthogonal data into the amplitude data and the phase data. When,
A delta-sigma modulator that delta-sigma-modulates the amplitude data to a binary value or more to reduce resolution of the amplitude data;
The delta-sigma modulator includes a multiplication unit that multiplies the amplitude data that is delta-sigma modulated by the phase data and outputs a signal having a resolution lower than that of the orthogonal data. Item 3. The data conversion device according to Item 2. The input signal is orthogonal data,
The signal processing unit
At least one subtraction unit to which the orthogonal data is input;
At least one vector integration unit connected to the subtraction unit and integrating each element of the orthogonal data;
For the orthogonal data integrated by the vector integration unit, at least two or more discrete values are used so that the integrated orthogonal data has a maximum discrete value smaller than the input orthogonal data. And quantizing the phase of the integrated orthogonal data to be equal to the phase of the input orthogonal data, and outputting a signal having a resolution lower than that of the input orthogonal data And
The data conversion apparatus according to claim 2, wherein the subtraction unit subtracts the orthogonal data quantized by the vector quantization unit from the input orthogonal data. The input signal is a modulated wave signal modulated based on orthogonal data,
The signal processing unit includes a delta-sigma modulator that outputs a signal having a resolution lower than that of the modulated wave signal by performing delta-sigma modulation of the modulated wave signal to two or more values. The data conversion device according to claim 2. The zero point of the noise transfer function of the signal processing unit is 1,
The data conversion apparatus according to claim 3, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The data conversion apparatus according to claim 4, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The data conversion apparatus according to claim 5, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The data conversion apparatus according to claim 3, wherein the filter is a band pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The data conversion apparatus according to claim 4, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The data conversion apparatus according to claim 5, wherein the filter is a band pass filter.   The cut-off frequency of the filter is smaller than half of the sampling frequency in the signal processing unit when the filter is a low-pass type, and the center frequency of the input signal when the filter is a band-pass type 3. The frequency according to claim 2, wherein the frequency is larger than a frequency obtained by subtracting 1/2 of the sampling frequency from the frequency and smaller than a frequency obtained by adding 1/2 of the sampling frequency to a center frequency of the input signal. Data converter. A transmission circuit that performs a predetermined process on an input signal and outputs a transmission signal,
A data converter that receives all or part of the input signal, performs predetermined data conversion on the input signal, and outputs the data;
A modulation amplification unit that performs at least one of modulation and amplification based on the signal converted by the data conversion unit;
A band-pass filter that outputs the transmission signal by removing unnecessary components outside the band at a predetermined cutoff frequency from the signal that has been modulated or amplified by the modulation amplification unit;
The data converter is
A signal processing unit that discretizes an input signal and generates a signal having a resolution lower than that of the input signal;
A first subtraction unit that subtracts the input signal from a low-resolution signal generated by the signal processing unit and extracts a quantization noise component generated in the signal processing unit;
A filter for band-limiting the quantization noise component extracted by the first subtraction unit with a predetermined cut-off frequency, and extracting a quantization noise component in the vicinity of a desired wave frequency that is a center frequency of the input signal; ,
By subtracting the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low-resolution signal generated by the signal processing unit, the signal having a lower resolution than the input signal is obtained. And a second subtractor that outputs a signal from which a quantization noise component near the desired wave frequency is removed. The input signal is orthogonal data,
The data conversion unit receives orthogonal data,
The modulation amplification unit includes:
A vector modulation unit for modulating the signal converted by the data conversion unit;
The transmission circuit according to claim 13, further comprising: an amplification unit that amplifies the signal modulated by the vector modulation unit to a predetermined output level.   The transmission circuit according to claim 14, wherein the vector modulation unit modulates by quadrature modulation. The input signal is orthogonal data,
The data conversion unit receives orthogonal data,
The modulation amplification unit includes:
A polar coordinate system conversion unit that converts the signal converted by the data conversion unit into polar coordinate data and outputs amplitude data and phase data;
An angle modulator that outputs an angle-modulated wave signal by angle-modulating the phase data;
An amplitude modulation unit that amplitude-modulates the angle-modulated wave signal with a voltage corresponding to the magnitude of the amplitude data;
The transmission circuit according to claim 13, further comprising: a voltage control unit that controls a voltage supplied to the amplitude modulation unit according to the magnitude of the amplitude data. The input signal is a modulated wave signal modulated based on orthogonal data,
The data converter receives the modulated wave signal,
The transmission circuit according to claim 13, wherein the modulation amplification unit includes an amplification unit that amplifies the signal converted by the data conversion unit to a predetermined output level. The input signal is polar coordinate data composed of amplitude data and phase data,
The amplitude conversion data is input to the data converter,
The modulation amplification unit includes:
An angle modulation unit that outputs an angle-modulated wave signal by angle-modulating the phase data;
An amplitude modulation unit that modulates the angle-modulated wave signal with a voltage corresponding to the magnitude of the signal output from the data conversion unit;
The transmission circuit according to claim 13, further comprising: a voltage control unit that controls a voltage supplied to the amplitude modulation unit according to a magnitude of a signal output from the data conversion unit. A transmission circuit that performs a predetermined process on an input signal and outputs a transmission signal,
A data converter that receives all or part of the input signal, performs predetermined data conversion on the input signal, and outputs the data;
A modulation amplification unit that performs modulation or amplification based on the signal converted by the data conversion unit;
The data converter is
A signal processing unit that discretizes an input signal and generates a signal having a resolution lower than that of the input signal;
A first subtraction unit that subtracts the input signal from a low-resolution signal generated by the signal processing unit and extracts a quantization noise component generated in the signal processing unit;
A filter for band-limiting the quantization noise component extracted by the first subtraction unit with a predetermined cut-off frequency, and extracting a quantization noise component in the vicinity of a desired wave frequency that is a center frequency of the input signal; ,
By subtracting the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low-resolution signal generated by the signal processing unit, the signal having a lower resolution than the input signal is obtained. And a second subtractor that outputs a signal from which a quantization noise component near the desired wave frequency is removed. The input signal is polar coordinate data composed of amplitude data and phase data,
The amplitude conversion data is input to the data converter,
The modulation amplification unit includes:
A voltage controller that controls an output voltage according to a signal converted by the data converter;
A low-pass filter that limits the voltage controlled by the voltage control unit at a predetermined cutoff frequency and removes noise components outside the band;
An angle modulator that outputs an angle-modulated wave signal by angle-modulating the phase data;
The transmission circuit according to claim 19, further comprising: an amplitude modulation unit that modulates the angle-modulated wave signal with a voltage output by the low-pass filter. The signal processing unit
A coordinate conversion unit that generates amplitude data indicating the size of the orthogonal data, generates the phase data by dividing the amplitude data from the orthogonal data, and converts the orthogonal data into the amplitude data and the phase data. When,
A delta-sigma modulator that delta-sigma-modulates the amplitude data to a binary value or more to reduce resolution of the amplitude data;
The delta sigma modulator includes a multiplication unit that multiplies the amplitude data that is delta sigma modulated by the phase data and outputs a signal having a resolution lower than that of the orthogonal data. Item 15. The transmission circuit according to Item 14. The signal processing unit
A coordinate conversion unit that generates amplitude data indicating the size of the orthogonal data, generates the phase data by dividing the amplitude data from the orthogonal data, and converts the orthogonal data into the amplitude data and the phase data. When,
A delta-sigma modulator that delta-sigma-modulates the amplitude data to a binary value or more to reduce resolution of the amplitude data;
The delta sigma modulator includes a multiplication unit that multiplies the amplitude data that is delta sigma modulated by the phase data and outputs a signal having a resolution lower than that of the orthogonal data. Item 17. The transmission circuit according to Item 16. The signal processing unit
At least one subtraction unit;
At least one vector integration unit connected to the subtraction unit and integrating each element of the orthogonal data;
For the orthogonal data integrated by the vector integration unit, at least two or more discrete values are used so that the integrated orthogonal data has a maximum discrete value smaller than the input orthogonal data. And quantizing the phase of the integrated orthogonal data to be equal to the phase of the input orthogonal data, and outputting a signal having a resolution lower than that of the input orthogonal data And
The transmission circuit according to claim 14, wherein the subtraction unit subtracts the orthogonal data quantized by the vector quantization unit from the input orthogonal data. The signal processing unit
At least one subtraction unit to which the orthogonal data is input;
At least one vector integration unit connected to the subtraction unit and integrating each element of the orthogonal data;
For the orthogonal data integrated by the vector integration unit, at least two or more discrete values are used so that the integrated orthogonal data has a maximum discrete value smaller than the input orthogonal data. And quantizing the phase of the integrated orthogonal data to be equal to the phase of the input orthogonal data, and outputting a signal having a resolution lower than that of the input orthogonal data And
The transmission circuit according to claim 16, wherein the subtraction unit subtracts the orthogonal data quantized by the vector quantization unit from the input orthogonal data.   The signal processing unit includes a delta-sigma modulator that outputs a signal having a resolution lower than that of the input signal by performing delta-sigma modulation of the input signal to two or more values. The transmission circuit according to claim 17.   The signal processing unit includes a delta-sigma modulator that outputs a signal having a resolution lower than that of the input signal by performing delta-sigma modulation of the input signal to two or more values. The transmission circuit according to claim 18. The zero point of the noise transfer function of the signal processing unit is 1,
The transmission circuit according to claim 21, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The transmission circuit according to claim 22, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The transmission circuit according to claim 23, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The transmission circuit according to claim 24, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
The transmission circuit according to claim 25, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is 1,
27. The transmission circuit according to claim 26, wherein the filter is a low-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The transmission circuit according to claim 21, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The transmission circuit according to claim 22, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The transmission circuit according to claim 23, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The transmission circuit according to claim 24, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
The transmission circuit according to claim 25, wherein the filter is a band-pass filter. The zero point of the noise transfer function of the signal processing unit is a complex number of size 1,
27. The transmission circuit according to claim 26, wherein the filter is a band pass filter.   The cut-off frequency of the filter is smaller than half of the sampling frequency in the signal processing unit when the filter is a low-pass type, and the center frequency of the input signal when the filter is a band-pass type 14. The frequency according to claim 13, wherein the frequency is larger than a frequency obtained by subtracting ½ of the sampling frequency from the frequency and smaller than a frequency obtained by adding ½ of the sampling frequency to the center frequency of the input signal. Transmitter circuit.   The cut-off frequency of the filter is smaller than half of the sampling frequency in the signal processing unit when the filter is a low-pass type, and the center frequency of the input signal when the filter is a band-pass type 21. The frequency according to claim 19, wherein the frequency is greater than a frequency obtained by subtracting 1/2 of the sampling frequency from the frequency, and smaller than a frequency obtained by adding 1/2 of the sampling frequency to a center frequency of the input signal. Transmitter circuit. Communication equipment,
A transmission circuit for generating a transmission signal;
An antenna for outputting a transmission signal generated by the transmission circuit;
The communication apparatus according to claim 13, wherein the transmission circuit is the transmission circuit according to claim 13. Communication equipment,
A transmission circuit for generating a transmission signal;
An antenna for outputting a transmission signal generated by the transmission circuit;
The communication device according to claim 19, wherein the transmission circuit is the transmission circuit according to claim 19. Electronic equipment,
An amplifier;
A data converter that converts an input signal into a signal for input to the amplifier and outputs the signal,
The data converter is
A signal processing unit that discretizes the input signal and generates a signal having a resolution lower than that of the input signal;
A first subtraction unit that subtracts the input signal from a low-resolution signal generated by the signal processing unit and extracts a quantization noise component generated in the signal processing unit;
A filter for band-limiting the quantization noise component extracted by the first subtraction unit at a predetermined cutoff frequency, and extracting a quantization noise component in the vicinity of a desired wave frequency that is a center frequency of the input signal;
By subtracting the quantization noise component in the vicinity of the desired wave frequency extracted by the filter from the low resolution signal generated by the signal processing unit, the desired wave is obtained from the signal having a lower resolution than the input signal. An electronic apparatus comprising: a second subtraction unit that outputs a signal from which a quantization noise component in the vicinity of a frequency is removed. A data conversion method for performing predetermined data conversion on an input signal and outputting the signal,
Discretizing the input signal to generate a signal with a lower resolution in magnitude than the input signal;
Subtracting the input signal from the low resolution signal generated by the generating step to extract the quantization noise component generated in the generating step;
The quantization noise component extracted by the step of extracting the quantization noise component is band-limited at a predetermined cut-off frequency, and the quantization noise component near the desired wave frequency that is the center frequency of the input signal is extracted. And steps to
By subtracting the quantization noise component in the vicinity of the desired wave extracted by the extracting step from the low resolution signal generated by the generating step, the signal having a resolution lower than that of the input signal Outputting a signal from which a quantization noise component in the vicinity of a desired wave frequency has been removed.

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