JP2017098708A - Phase locked loop circuit, rf front end circuit, radio transmitting/receiving circuit and portable radio communication terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase locked loop circuit capable of stabilizing a frequency of an input signal even in the case where the frequency becomes unstable.SOLUTION: The present invention relates to a phase locked loop circuit 12 for correcting an error between a frequency of an output signal LSof an oscillator and a predetermined target frequency. The phase locked loop circuit comprises: an ADC 121 for performing A/D conversion on the output signal LS; reference frequency output means 123 which outputs a reference frequency signal S; error frequency detection means 122a by which, upon receiving input of the A/D converted output signal LSand the reference frequency signal S, an error between a frequency of the output signal LSand the target frequency is calculated; correction signal generation means 122b for generating an error correction signal LSbased on the error; a DAC 124 for performing D/A conversion on the error correction signal LS; and a multiplier 125 which multiplies the output signal LSand the D/A converted error correction signal LS.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phase synchronization circuit, an RF front end circuit using the same, a wireless transmission / reception circuit, and a portable wireless communication terminal device.

  The amount of communication by wireless communication by mobile terminals such as mobile phones, smartphones, and mobile routers continues to increase year by year as terminal devices become more sophisticated and distribution contents such as moving image files and music files are enhanced. In order to meet such demand, development of wireless communication technology is also progressing. At present, various terminal devices and base station equipment corresponding to the fourth generation (4G) communication standard are widely used, and are widely used in general.

  A signal transmitted and received by the antenna in the wireless communication terminal device as described above is a signal having a high frequency called an RF (Radio Frequency) signal. When the RF signal is received, the RF front-end circuit performs down-conversion by multiplying it with the output signal of the local oscillator, and converts it to a band including information itself exchanged by communication called baseband. To do. In addition, when transmitting information, the baseband signal is multiplied by the output signal of the local oscillator, up-converted, and transmitted from the antenna as an RF signal.

  Generally, an oscillator such as a VCO (Voltage-Controlled Oscillator) is used as the local oscillator. A VCO is an oscillation circuit that controls an output frequency by an input control voltage. Usually, a control voltage is generated by a phase synchronization circuit, and an error caused by various factors is corrected in the frequency of the output signal of the VCO, and used as a local oscillator.

  For example, Patent Document 1 has a configuration in which an output of a VCO is input to an ADC (Analog-to-Digital Converter), a phase comparison is performed using digital data after conversion, and a control voltage of the VCO is output based on the phase comparison. Thus, a phase synchronization circuit for stabilizing the frequency is described.

  In communication after the fourth generation, multilevel modulation such as 256QAM (256 Quadrature Amplitude Modulation) is used. For this purpose, it is necessary to keep the frequency of the local oscillator constant. For this purpose, the frequency of the local oscillator is stabilized by the phase synchronization circuit.

  Further, in the above-mentioned fourth generation communication standard, communication using a plurality of subcarriers called OFDMA (Orthogonal Frequency-Division Multiple Access) is used to improve the efficiency of use of the frequency band. It is increasing. By using a local oscillator having a high spectral purity, it is possible to prevent interference between subcarriers and increase the communication capacity by using the frequency band more efficiently.

  Examples of the oscillator having higher spectral purity include a SAW (Surface Acoustic Wave) oscillator. The SAW oscillator is also used in combination with a phase locked loop and its output frequency is stabilized. In order to stabilize the frequency of the SAW oscillator, a technique by adjusting the voltage applied to the varicap (variable capacitance diode) is mainly used.

  Further, MIMO (Multiple-Input and Multiple-Output) is known as a technique for increasing the capacity of wireless communication. This is to increase the communication capacity by using a plurality of transmission / reception systems including an antenna, a modulator, a demodulator, etc. in both of the transceivers used for wireless communication.

JP 2000-138581 A

  As described above, in a current wireless communication terminal device, a VCO is generally used as a local oscillator. As described above, one technique for increasing the communication capacity is to increase the spectral purity of the local oscillator, but there is a limit to increasing the spectral purity of the VCO.

  Since the SAW oscillator is an oscillator having a spectral purity higher than that of the VCO, if it can be used as a local oscillator, an increase in communication capacity can be expected. However, since the SAW oscillator has a characteristic that it is vulnerable to external impacts and temperature changes, when it is used in a wireless communication device such as a mobile phone, the above-described frequency stabilization by the varicap described above provides a stable output. There was a problem that it was difficult to obtain the frequency.

  Therefore, the present invention provides a phase synchronization circuit that can stabilize the frequency of the input signal even when the frequency of the input signal becomes unstable, and increase communication capacity by using the phase synchronization circuit. An object of the present invention is to provide a wireless transmission / reception circuit capable of performing the above.

In order to solve the above problems, a phase locked loop circuit according to the present invention includes:
A phase synchronization circuit that corrects an error between the frequency of the output signal of the oscillator and a predetermined target frequency,
An ADC for analog-to-digital conversion of the output signal;
A reference frequency output means for outputting a reference frequency signal;
Error frequency detection means for receiving an input of the analog-digital converted output signal and the reference frequency signal and calculating an error between the frequency of the output signal and the target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
DAC that performs digital-analog conversion of the error correction signal;
A multiplier that multiplies the output signal by the digital-analog converted error correction signal.

  Thus, the frequency of the output signal of the oscillator is unstable by correcting the frequency error of the output signal by a method of synthesizing the frequency correction signal generated based on the error between the frequency of the output signal of the oscillator and the target frequency. In some cases, it can be stabilized.

In a preferred aspect of the present invention, an output signal of a SAW oscillator is used as the input signal.
As a result, the phase of the output signal of the SAW oscillator, which has high spectral purity but is vulnerable to temperature changes and external shocks, is provided to provide a signal having high spectral purity and a stable frequency. Can do.

The RF front-end circuit according to the present invention is
An RF front-end circuit that converts a received signal received by an antenna into a baseband input signal and converts a baseband output signal into a transmission signal transmitted by the antenna,
A local oscillator,
A phase synchronization circuit that performs phase synchronization of the output signal of the local oscillator;
A first multiplier for multiplying the received signal by the output signal of the phase locked loop and outputting the baseband input signal;
A second multiplier that multiplies the baseband output signal and the output signal of the phase synchronization circuit and outputs the transmission signal;
The phase synchronization circuit is
An ADC for analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
Error frequency detection means for receiving an output of the analog-digital converted output signal of the local oscillator and the reference frequency signal and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generating means for generating a frequency correction signal based on the error;
A DAC for digital-analog conversion of the frequency correction signal;
And a multiplier for multiplying the output signal of the local oscillator by the frequency-corrected signal converted from digital to analog.
As described above, by configuring the RF front-end circuit using the phase locked loop according to the present invention, stable operation can be expected even when a local oscillator that is weak against temperature change and external shock is used.

In a preferred aspect of the present invention, the local oscillator is a SAW oscillator.
Thus, by using a SAW oscillator having a high spectral purity as a local oscillator, a local oscillation signal having a high spectral purity can be provided and the communication capacity can be increased.

A portable wireless communication terminal apparatus according to the present invention includes the RF front end circuit described above.
As described above, by using the RF front-end circuit according to the present invention, it is possible to perform stable wireless communication even in a portable terminal device exposed to a temperature change or an external impact.

A wireless transmission / reception circuit according to the present invention includes:
A radio transmission / reception circuit that performs conversion of input signals received by an antenna into input data and conversion of output data into transmission signals transmitted from the antenna,
A local oscillator,
A first ADC that performs analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
An error frequency detection means for receiving an input of the output signal of the local oscillator and the reference frequency signal which have been analog-digital converted, and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
A first multiplier that multiplies the output signal of the local oscillator and the received signal to generate a baseband input signal;
A second ADC that performs analog-to-digital conversion of the baseband input signal;
A second multiplier that multiplies the analog-to-digital converted baseband input signal and the error correction signal;
Demodulation means for demodulating the output signal of the second multiplier and outputting the output data;
Modulation means for modulating the output data;
A third multiplier for multiplying the output signal of the modulation means by the error correction signal and outputting a baseband output signal;
A DAC for digital-analog conversion of the baseband output signal;
And a fourth multiplier that multiplies the digital-analog converted baseband output signal and the output signal of the local oscillator to generate a transmission signal.
Thus, by adopting a configuration in which correction of the frequency error of the local oscillator is performed at the time of demodulation and modulation, the number of DACs necessary for the configuration can be reduced, and the manufacturing cost and power consumption can be suppressed.

  In a preferred aspect of the present invention, the local oscillator is a SAW oscillator.

  A portable wireless communication terminal apparatus according to the present invention includes the above-described wireless transmission / reception circuit.

A wireless transmission / reception circuit according to the present invention includes:
A first received signal received by the first antenna and a second received signal received by the second antenna are converted into input data, and output data is transmitted from the first antenna; A wireless transmission / reception circuit that performs conversion to a second transmission signal transmitted from the second antenna,
A local oscillator,
A first ADC that performs analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
An error frequency detection means for receiving an input of the output signal of the local oscillator and the reference frequency signal which have been analog-digital converted, and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
A first multiplier that multiplies the output signal of the local oscillator and the first received signal to generate a first baseband input signal;
A second multiplier that multiplies the output signal of the local oscillator and the second received signal to generate a second baseband input signal;
A second ADC that performs analog-to-digital conversion of the first baseband input signal;
A third ADC that performs analog-to-digital conversion of the second baseband input signal;
A third multiplier for multiplying the first baseband input signal that has been analog-to-digital converted by the error correction signal;
A fourth multiplier that multiplies the second baseband input signal that has been analog-to-digital converted by the error correction signal;
First demodulation means for demodulating the output signal of the third multiplier and outputting first demodulated data;
Second demodulating means for demodulating the output signal of the fourth multiplier and outputting second demodulated data;
Data integration means for integrating the first demodulated data and the second demodulated data to generate the output data;
Data dividing means for dividing the output data into first modulation target data and second modulation target data;
First modulation means for modulating the first modulation target data;
Second modulation means for modulating the second data to be modulated;
A fifth multiplier for multiplying the output signal of the first modulation means by the error correction signal and outputting a first baseband output signal;
A sixth multiplier for multiplying the output signal of the second modulation means by the error correction signal and outputting a second baseband output signal;
A first DAC that performs digital-to-analog conversion of the first baseband output signal;
A second DAC that performs digital-to-analog conversion of the second baseband output signal;
A seventh multiplier that multiplies the first baseband output signal that has been digital-to-analog converted by the output signal of the local oscillator to generate the first transmission signal;
And an eighth multiplier that multiplies the second baseband output signal that has been digital-analog converted by the output signal of the local oscillator and generates the second transmission signal. .
In this way, the communication capacity can be increased by adopting a configuration including a plurality of transmission / reception paths.

  In a preferred aspect of the present invention, the local oscillator is a SAW oscillator.

  A portable wireless communication terminal apparatus according to the present invention includes the above-described wireless transmission / reception circuit.

The frequency stabilization method according to the present invention includes:
A frequency stabilization method for correcting an error between a frequency of an output signal of an oscillator and a predetermined target frequency,
Performing analog-to-digital conversion of the input signal;
Comparing the analog-digital converted frequency of the output signal with a reference frequency and calculating the error;
Generating an error correction signal for correcting the error;
Performing digital-analog conversion of the error correction signal;
Multiplying the input signal by the digital-analog converted error correction signal.

A method of demodulating a radio reception signal according to the present invention includes:
A method of demodulating a radio reception signal that converts reception signal received by an antenna into input data,
Multiplying the received signal and the output signal of the local oscillator to generate a baseband input signal;
Performing analog-to-digital conversion of the baseband input signal;
Performing analog-to-digital conversion of the output signal of the local oscillator;
Calculating an error between the frequency of the local oscillator output signal and a predetermined target frequency from the analog-digital converted output signal of the local oscillator;
Generating an error correction signal based on the error; multiplying the analog-to-digital converted baseband input signal by the error correction signal;
And demodulating a signal obtained by multiplying the baseband input signal and the error correction signal and outputting the input data.

A modulation method of a radio transmission signal according to the present invention includes:
A radio transmission signal modulation method for converting output data into a transmission signal to be transmitted from an antenna,
Performing analog-to-digital conversion of the output signal of the local oscillator;
Calculating an error between the frequency of the local oscillator output signal and a predetermined target frequency from the analog-digital converted output signal of the local oscillator;
Generating an error correction signal based on the error; modulating the output data;
Multiplying the signal obtained by modulating the output data and the error correction signal, and outputting a baseband output signal;
Performing digital-analog conversion of the baseband output signal;
And a step of multiplying the digital-analog converted baseband output signal and the output signal of the local oscillator to generate the transmission signal.

  A phase synchronization circuit that can stabilize the frequency by correcting the frequency error of the output signal by synthesizing the frequency correction signal with the output signal of the oscillator. A wireless transmission / reception circuit which can be increased in capacity can be provided.

1 is a block diagram of a phase synchronization circuit according to a first embodiment of the present invention. It is a flowchart which shows the frequency stabilization process in Embodiment 1 of this invention. It is a block diagram of the radio | wireless transmission / reception circuit which concerns on Embodiment 1 of this invention. It is a flowchart which shows the data reception process in Embodiment 1 of this invention. It is a flowchart which shows the transmission process of the data in Embodiment 1 of this invention. It is a block diagram of the radio | wireless transmission / reception circuit which concerns on Embodiment 2 of this invention. It is a flowchart which shows the detection process of the error frequency in Embodiment 2 of this invention. It is a flowchart which shows the data reception process in Embodiment 2 of this invention. It is a flowchart which shows the transmission process of the data in Embodiment 2 of this invention. It is a block diagram of the radio | wireless transmission / reception circuit which concerns on Embodiment 3 of this invention. It is a flowchart which shows the data reception process in Embodiment 3 of this invention. It is a flowchart which shows the transmission process of the data in Embodiment 3 of this invention.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the phase synchronization circuit 12 according to the present embodiment. This corrects the frequency f _raw of the SAW oscillator output signal LS _raw , which is an output signal of the SAW oscillator 11, shown as an example of use of the phase locked loop 12 according to the present embodiment to a predetermined target frequency f _tgt . And a local oscillator output signal LS _out used in the radio transmission / reception circuit.

As shown here, the phase synchronization circuit 12 receives an ADC 121 that performs analog-digital conversion of the SAW oscillator output signal LS _{raw that is} an analog signal, and an input of the SAW oscillator output signal LS _raw that has been converted into a digital signal. A DSP 122 that generates an error correction signal LS _err for matching the frequency f _raw and the target frequency f _tgt, and a reference frequency output means 123 that outputs a reference frequency signal S _ref having a reference frequency f _ref to the DSP 122. The DAC 124 that performs digital-analog conversion of the error correction signal LS _{err that is} a digital signal, the SAW oscillator output signal LS _{raw that} is an analog signal, and the error correction signal LS _err that is also converted to an analog signal are multiplied. And a multiplier 125 for performing.

DSP122 further includes a SAW oscillator output signal _{LS raw} which is converted into a digital signal, receives the reference frequency signal _{S ref,} is the error between the frequency _{f raw} and the target frequency _{f tgt} of the SAW oscillator output signal _{LS raw} comprises an error frequency detection means 122a for calculating the error frequency _{f err,} and the correction signal generating means 122b for generating an error correction signal _{LS err} with error frequency _{f err,} a.

  The DSP 122 is a digital signal processor (Digital Signal Processor), that is, a microprocessor for performing digital signal processing. Moreover, it is good also as a structure which replaces with DSP and uses CPU (Central Processing Unit). However, since the error frequency detection means 122a and the correction signal generation means 122b are required to perform high-speed processing, it is preferable to use a DSP in order to cope with them.

The reference frequency signal S _ref may be, for example, an analog-digital converted signal output from a crystal oscillator.

FIG. 2 is a flowchart showing the correction process of the SAW oscillator output signal LS _raw by the phase synchronization circuit 12. First, in step S11, the ADC 121 performs analog-digital conversion of the SAW oscillator output signal LS _raw .

In step S12, the SAW oscillator output signal LS _raw converted into the digital signal and the reference frequency signal S _ref are input to the error frequency detection unit 122a, and the frequency f _{raw of} the SAW oscillator output signal LS _raw is input. An error from the target frequency f _tgt is calculated.

Here, since the purpose is to obtain the local oscillator output signal LS _out used in the radio transmission / reception circuit as described above, the target frequency f _tgt is a high frequency band such as several hundred megahertz to several gigahertz. On the other hand, the reference frequency f _ref is a stable frequency in a frequency band of about several tens of megahertz.

Therefore, in calculating the error by the error frequency detection unit 122a, more specifically, N times the reference frequency f _ref (N is an arbitrary number) becomes the target frequency f _tgt , or the frequency of the reference frequency f _ref The reference frequency f _ref is used such that 1 / N of N becomes the target frequency f _tgt .

Then, the process proceeds to step S13, and an error correction signal LS _err having the error frequency f _ref obtained in step S12 is generated by the correction signal generation means 122b. More specifically, the error correction signal LS _err is a sine wave having an error frequency f _err .

In step S14, the DAC 124 performs digital-analog conversion of the error correction signal LS _err .

Finally, in step S15, the multiplier 125 multiplies the SAW oscillator output signal LS _{raw that} is an analog signal and the error correction signal LS _err converted to the analog signal. Here, since the error frequency f _err is a frequency indicating an error between the target frequency f _tgt and the frequency f _raw of the SAW oscillator output signal LS _raw , the relationship between these frequencies is as shown in Expression (1). It has become.

Therefore, the local oscillator output signal LS _out obtained by the multiplication in the multiplier 125 has the target frequency f _tgt as shown in Expression (2).

Here, in the multiplication by the multiplier 125, a signal having a frequency (f _raw + f _err ) larger than the frequency f _{raw of} the SAW oscillator output signal LS _raw shown in Expression (2) by the error frequency f _err , Both signals having a frequency (f _raw −f _err ) smaller than the frequency f _{raw of the} SAW oscillator output signal LS _raw by the error frequency f _err are obtained. Among these signals, a signal used as the local oscillator output signal LS _out is determined by determining the magnitude relationship between the target frequency f _tgt and the frequency f _raw of the SAW oscillator output signal LS _{raw in accordance} with the condition shown in the expression (2). Just choose.

Alternatively, as shown in Equation (3), the error frequency f _err may take a negative value, and an IQ modulator (orthogonal modulator) may be used as the multiplier 125.

In such a configuration, when the frequency f _raw of the SAW oscillator output signal LS _raw is smaller than the target frequency f _tgt (f _tgt > f _raw ), the error frequency f _err takes a positive value. . Therefore, by multiplying the error correction signal _{LS err} to the SAW oscillator output signal _{LS raw,} it signals a local oscillator having a large frequency by the absolute value of the error frequency _{f err} than the frequency _{f raw} of the SAW oscillator output signal _{LS raw} It can be obtained as the output signal LS _out . Conversely, when the frequency f _raw of the SAW oscillator output signal LS _raw is larger than the target frequency f _tgt (f _tgt <f _raw ), the error frequency f _err takes a negative value. Therefore, by multiplying the error correction signal _{LS err} to the SAW oscillator output signal _{LS raw,} it signals a local oscillator with the absolute value of only a small frequency error frequency _{f err} than the frequency _{f raw} of the SAW oscillator output signal _{LS raw} It can be obtained as the output signal LS _out .

As described above, the phase synchronization circuit 12 according to the present embodiment corrects the error of the SAW oscillator output signal LS _raw by the digital arithmetic processing by the DSP 122 and outputs the local oscillator output signal LS _out having the target frequency f _tgt. can do.

  Next, a radio transmission / reception circuit according to the present embodiment using a circuit constituted by the SAW oscillator 11 and the phase synchronization circuit 12 shown in FIG. 1 as a local oscillator will be described.

FIG. 3 is a block diagram showing a wireless transmission / reception circuit according to this embodiment. As shown here, the wireless transceiver circuit according to this embodiment includes an antenna ANT for transmitting and receiving radio signals, converted into baseband input signal BS _in the received signal RS _rcv received by the antenna ANT, and a baseband output RF front-end circuit 1 for converting signal BS _out to transmission signal RS _snd transmitted by antenna ANT, output of input data D _in to system SYS by demodulation of baseband input signal BS _in , and from system SYS comprises, a baseband processing unit 2 for outputting a base band output signal _{BS out} by the modulation of the output data _{D out.}

The RF front-end circuit 1 includes a SAW oscillator 11, a phase synchronization circuit 12, a transmission / reception switch SW that switches transmission / reception by the antenna ANT, a bandpass filter 17 that extracts a signal in a necessary frequency band from the reception signal RS _rcv , performs multiplication of the received signal _{RS rcv} after application of the local oscillator output signal _{LS out} a band-pass filter 17, a multiplier 13 for outputting a baseband input signal _{BS in,} baseband input signals _{BS in} analog - digital conversion and ADC15 performing, digital baseband output signal _{BS out} - and DAC16 of performing analog conversion, a multiplier 14 for multiplying the baseband output signal _{BS out} which is converted to the local oscillator output signal _{LS out} and analog signals, the Have.

Baseband processor 2 performs a demodulation process of the baseband input signal _{BS in,} the demodulation means 21 for outputting the input data _{D in} to the system SYS, modulates the output data _{D out} of the system SYS, the baseband Modulation means 22 for outputting the output signal BS _out .

  Here, the system SYS is an arbitrary system that requests transmission / reception of data by wireless communication. For example, when the wireless transmission / reception circuit according to the present embodiment is used for a mobile phone, a smartphone terminal, or the like, the system SYS is an input / output by an OS (Operating System, basic software), or various application programs through the input / output. obtain. Or when using the radio | wireless transmission / reception circuit which concerns on this embodiment for base stations, such as a mobile telephone, it can be a system which manages it.

Further, the local oscillator output signal LS _out is a signal having a target frequency f _tgt that is obtained by stabilizing the frequency f _raw of the SAW oscillator output signal LS _raw as described above.

FIG. 4 is a flowchart showing a process of obtaining the input data D _in by demodulating the reception signal RS _rcv by the radio transmission / reception circuit according to the present embodiment. First, in step S21, by applying a band-pass filter 17 the received signal _{RS rcv,} to extract only a signal of a necessary frequency band from the received signal _{RS rcv.}

In step S22, the multiplier 13 multiplies the received signal RS _rcv after application of the bandpass filter and the local oscillator output signal LS _out by the multiplier 13 to generate the baseband input signal BS _in .

Analog baseband input signal _{BS in} Step S23 - performs digital conversion, by the demodulation process in step S24, generates an input data _{D in} to the system SYS, the process ends.

As described above, the radio transmission / reception circuit according to the present embodiment can demodulate the received signal RS _rcv to obtain the input data D _in to the system SYS.

5, the radio transceiver circuit according to this embodiment, modulates the output data _{D out} of the system SYS, a flowchart illustrating a process of obtaining a transmission signal _{RS snd.} First, in step S31, it performs modulation processing of the output data _{D out} of the system SYS, and generates a baseband output signal _{BS out.}

Then, in step S32, the digital baseband output signal _{BS out} by DAC 16 - performs analog conversion.

In subsequent step S33, the baseband output signal BS _out converted into the analog signal is multiplied by the local oscillator output signal LS _out to generate a transmission signal RS _snd from the antenna ANT.

As described above, the wireless transceiver circuit according to this embodiment performs modulation processing of the output data D _out of the system SYS, it is possible to obtain a transmission signal RS _snd.

  Note that the reception process as shown in FIG. 4 and the transmission process as shown in FIG. 5 can be performed by switching the transmission / reception selector switch SW.

  As described above, by using the phase synchronization circuit 12 according to the present embodiment, a wireless transmission / reception circuit using the SAW oscillator 11 as a local oscillator can be configured. As a result, the problem of the SAW oscillator that is weak against external shocks and temperature changes is solved by frequency stabilization processing by digital calculation using the phase synchronization circuit 12, and the advantage of the SAW oscillator that has high spectral purity is utilized. Can do.

(Embodiment 2)
FIG. 6 is a block diagram showing a wireless transmission / reception circuit according to the second embodiment of the present invention. In this embodiment, components that are basically the same as those in the first embodiment are denoted by the same reference numerals and description thereof is simplified.

As shown in FIG. 6, the radio transmission / reception circuit according to the present embodiment includes an antenna ANT that transmits and receives radio signals, a conversion of a received signal RS _rcv received by the antenna ANT into a baseband input signal BS _in , and a baseband. An RF front-end circuit 1 that converts the output signal BS _out to a transmission signal RS _snd transmitted by the antenna ANT, an output of input data D _in to the system SYS by demodulation of the baseband input signal BS _in , and a system SYS It comprises, a baseband processing unit 2 for outputting a base band output signal _{BS out} by modulation of the output data _{D out} of.

The RF front end circuit 1 includes a SAW oscillator 11, a transmission / reception selector switch SW that switches transmission / reception by the antenna ANT, a bandpass filter 17 that extracts a signal in a necessary frequency band from the reception signal RS _rcv, and a SAW oscillator output signal LS _raw. and performs multiplication of the received signal _{RS rcv} after treatment with the bandpass filter 171, a multiplier 13 for outputting a baseband input signal _{BS in,} analog baseband input signal _{BS in} - the ADC15 which performs digital conversion, based digital band output signal _{BS out} - and DAC16 of performing analog conversion, a multiplier 14 for multiplying the baseband output signal _{BS out} which is converted into SAW oscillator output signal _{LS out} and analog signals, the SAW oscillator output signal _{LS raw} Analog-digital conversion And ADC18 to perform, with a.

Baseband processor 2 performs a demodulation process of the baseband input signal _{BS in,} the demodulation means 21 for outputting the input data _{D in} to the system SYS, modulates the output data _{D out} of the system SYS, the baseband Modulation means 22 for outputting the output signal BS _out .

Further, the baseband processing unit 2 outputs a reference frequency signal S _ref having a reference frequency f _ref and outputs a reference frequency signal S _ref , an analog-digital converted SAW oscillator output signal LS _raw and a reference frequency signal S by the ADC 18. An error frequency detecting means 23 that receives an input of _ref and calculates an error frequency f _err , which is an error between the target frequency f _tgt and the frequency f _raw of the SAW oscillator output signal LS _raw , and error correction having an error frequency f _err multiplied by the correction signal generation means 25 for generating a signal _{LS err,} a multiplier 26 for multiplying the error correction signal _{LS err} to baseband input signals _{BS in,} the error correction signal _{LS err} in baseband output signals _{BS out} And a multiplier 27. Here, the target frequency f _tgt is a frequency expected for the SAW oscillator output signal LS _raw and is a value determined in advance according to a frequency band in which transmission / reception is performed by the wireless transmission / reception circuit. Ideally, the frequency f _raw of the SAW oscillator output signal LS _raw and the target frequency f _tgt are equal, but in reality, the SAW oscillator 11 is affected by an external impact, a temperature change, and the like, so that an error occurs.

In the present embodiment, in the RF front end circuit 1, the SAW oscillator output signal LS _raw , which is the output of the SAW oscillator 11, is not used for frequency stabilization but is used as it is as the output of the local oscillator. Then, in the baseband processing unit 2, the correction using the error correction signal LS _err is performed before the demodulation process and after the modulation process, whereby the frequency f _raw and the target frequency f of the SAW oscillator output signal LS _raw are obtained. An error generated during _tgt is corrected.

7, in a radio transceiver circuit according to this embodiment is a flowchart illustrating a process for calculating an error between SAW oscillator output signal _{LS raw} frequency _{f raw} and the target frequency _{f tgt.} First, in step S41, the ADC 18 performs analog-digital conversion of the SAW oscillator output signal LS _raw .

Then, the SAW oscillator output signal LS _raw converted to the digital signal and the reference frequency signal S _ref output from the reference frequency signal output means 24 are input to the error frequency detection means 23, and the SAW oscillator output signal LS _raw is An error frequency f _err between the frequency f _raw and the target frequency f _tgt is calculated, and an error correction signal LSerr, which is a sine wave having the error frequency f _err , is generated in step S43. This is the same processing as that performed using the DSP 122 in the phase synchronization circuit 12 in the first embodiment.

The error correction signal LS _err generated in this way is used for correction processing in demodulation processing and modulation processing described later.

FIG. 8 is a flowchart showing a process of obtaining the input data D _in by demodulating the reception signal RS _rcv by the wireless transmission / reception circuit according to the present embodiment. First, apply a band-pass filter 17 the received signal _{RS rcv} at step S51, to extract only a signal of a necessary frequency band from the received signal _{RS rcv.}

In step S52, the multiplier 13 multiplies the received signal RS _rcv after application of the bandpass filter 17 and the SAW oscillator output signal LS _raw by the multiplier 13 to generate a baseband input signal BS _in . Since the SAW oscillator output signal LS _raw is used for down-conversion of the received signal RS _rcv , at this time, the baseband input signal BS _in is _{equal to} the frequency f _raw of the SAW oscillator output signal LS _raw and the target frequency f _tgt . This is a state including an error component.

In step S53, analog-digital conversion of the baseband input signal BS _in is performed. In step S54, the multiplier 26 multiplies the baseband input signal BS _in converted into the digital signal by the error correction signal LS _err . As a result, the influence of the error between the frequency f _raw of the SAW oscillator output signal LS _raw and the target frequency f _tgt can be canceled.

Then, in step S55, demodulation processing by the demodulating means 21 is performed, input data D _in to the system SYS is generated, and the processing ends.

9, the wireless transceiver circuit according to this embodiment, modulates the output data _{D out} of the system SYS, a flowchart illustrating a process of obtaining a transmission signal _{RS snd.} First, in step S61, it performs modulation processing of the output data _{D out} of the system SYS, and generates a baseband output signal _{BS out.} Incidentally, in this time, the baseband output signal _{BS out} is a state in which no consideration of errors of the frequency _{f raw} and the target frequency _{f tgt} of the SAW oscillator output signal _{LS raw.}

Then, in step S62, performs the baseband output signal _{BS out} and the error correction signal _LS multiplier 27 multiplies _err, baseband output signals _{BS out} the SAW oscillator output signal _{LS raw} frequency _{f raw} and the target frequency _{f tgt} The correction component of the error of is included.

More specifically, when the frequency f _raw of the SAW oscillator output signal LS _raw is lower than the target frequency f _tgt (f _tgt > f _raw ), the baseband output signal BS is multiplied by the multiplier 27. _When the frequency of _out is decreased by the error frequency f _{err and} the frequency f _{raw of} the SAW oscillator output signal LS _raw is larger than the target frequency f _tgt (f _tgt <f _raw ), the baseband is multiplied by the multiplier 27. In this process, the frequency of the output signal BS _out is reduced by the error frequency f _err . Thereby, when the baseband output signal BS _out and the SAW oscillator output signal LS _raw are multiplied later in step S64, the transmission signal RS _snd that is not affected by the error can be obtained.

In step S63, the DAC 16 performs digital-analog conversion of the baseband output signal BS _out , and in the subsequent step S33, the baseband output signal BS _out converted into the analog signal and the SAW oscillator output signal LS _raw. To generate a transmission signal _RSsnd from the antenna ANT. Here, the error of the SAW oscillator output signal LS _raw is canceled out by the correction component included in the baseband output signal BS _out in step S62, and the transmission signal _RSsnd is not affected by the error. Become.

  The reception process as shown in FIG. 8 and the transmission process as shown in FIG. 9 can be performed by switching the transmission / reception selector switch SW.

  As described above, by using wireless transmission / reception in the present embodiment, even when the SAW oscillator 11 is used as a local oscillator without performing frequency stabilization by the phase synchronization circuit, error correction is performed by digital calculation in the baseband processing unit. It can be performed.

With such a configuration, in the first embodiment, the DAC 124 that performs digital-analog conversion of the error correction signal LS _{err in} the phase synchronization circuit 12 and the DAC 16 that performs digital-analog conversion of the baseband output signal BS _out are included. the place of two DAC was required, digital baseband output signal _{BS out} - as only DAC16 of performing analog conversion can be omitted one DAC. As a result, the circuit can be reduced in size and power can be saved.

  The baseband processing unit 2 is realized by a DSP and performs digital calculation. For this reason, the addition of components such as error correction multipliers 26 and 27 in the baseband processing unit 2 can be realized by adding logical processing blocks in the DSP. Therefore, a multiplier as an analog element is added. Compared to the case, increase in circuit scale, power consumption, and production cost can be suppressed.

  If the multiplier 13, the multiplier 14, the ADC 15, the DAC 16, the ADC 18, the demodulating unit 21, the modulating unit 22, the error frequency detecting unit 23, and the like are configured as a single IC (Integrated Circuit), a radio transmission / reception circuit Can be further reduced in scale.

  Also in this embodiment, the system SYS may be an arbitrary system that requests transmission / reception of data by wireless communication, and the wireless transmission / reception circuit according to this embodiment is a terminal device such as a mobile phone or a smartphone terminal. To equipment such as a mobile phone or other base station, can be used for various wireless communication devices.

(Embodiment 3)
FIG. 10 is a block diagram showing a wireless transmission / reception circuit according to this embodiment. In the same embodiment, components that are basically the same as those in the first and second embodiments are denoted by the same reference numerals and description thereof is simplified.

As shown in FIG. 10, the radio transmission / reception circuit according to the present embodiment includes two antennas, an antenna ANT1 and an antenna ANT2, that transmit and receive radio signals, and basebands of received signals RS _rcv 1 and RS _rcv 2 received by them. RF front end for converting the input signals BS _in 1 and BS _in 2 and converting the baseband output signals BS _out 1 and BS _out 2 to the transmission signals RS _snd 1 and RS _snd 2 transmitted by the antennas ANT1 and ANT2. Output of input data D _in to the system SYS by demodulation and data integration of the circuit 1 and base band input signals BS _in 1 and BS _in 2, and baseband output by data division and modulation of the output data D _out from the system SYS perform the output of the signal _{BS out 1, BS} out 2 It includes a baseband processing unit 2, a.

  As described above, the wireless transmission / reception circuit according to the present embodiment includes two transmission / reception circuits, is compatible with the MIMO technology, and can increase the communication capacity as compared with the case where one transmission / reception circuit is used. is there.

The RF front end circuit 1 includes a SAW oscillator 11 and an ADC 18 that performs analog-digital conversion of the SAW oscillator output signal LS _raw as a configuration shared by the two transmission / reception circuits described above.

Further, a transmission / reception changeover switch SW1 for switching transmission / reception by the antenna ANT1, which constitutes the first transmission / reception system, a bandpass filter 171 for extracting a signal of a necessary frequency band from the reception signal RS _rcv 1, and a SAW oscillator output signal LS _raw And a reception signal RS _rcv 1 processed by the bandpass filter 171 to output a baseband input signal BS _in 1, and an ADC 151 that performs analog-digital conversion of the baseband input signal BS _in , digital baseband output signal _{BS out} 1 - has a DAC161 of performing analog conversion, a multiplier 141 for multiplying the baseband output signal _{BS out} 1 which is converted into SAW oscillator output signal _{LS raw} analog signal.

Similarly, a transmission / reception changeover switch SW2 that switches between transmission and reception by the antenna ANT2, which constitutes the second transmission / reception system, a bandpass filter 172 that extracts a signal in a necessary frequency band from the reception signal RS _rcv 2, and a SAW oscillator output signal LS performs multiplication of the received signal _{RS rcv} 2 after treatment with _raw and band-pass filter 172, a multiplier 132 which outputs the baseband input signal _{BS in} 2, analog baseband input signal _{BS in} - performing digital conversion ADC152 has a DAC162 of performing analog conversion, a multiplier 142 for multiplying the baseband output signals _{BS out} 2 that has been converted into SAW oscillator output signal _{LS raw} analog signal, the - when, in the digital baseband output signals _{BS out} 2 .

  As described above, the RF front-end circuit 1 includes two components other than the SAW oscillator 11 and the ADC 18 shared by the two transmission / reception systems, in order to use each of the two transmission / reception systems.

The baseband processor 2, a configuration using a first transmission and reception system performs demodulation processing of the baseband input signal _{BS in} 1, a demodulation means 211 for outputting the input data _{D in} 1, the output data _{D out} 1 Modulation means 221 that performs modulation and outputs a baseband output signal BS _out 1.

Similarly, as a configuration used in the second transmission / reception system, demodulation processing of the baseband input signal BS _in 2 is performed, demodulation means 212 that outputs the input data D _in 2, modulation of the output data D _out 2, Modulation means 222 for outputting a baseband output signal BS _out 2.

In addition, in order to remove the influence of interference generated by the antennas ANT1 and ANT2, the input of the input data D _in 1 and D _in 2 demodulated by the demodulation means 211 and 212 is received, and separation of data in which interference has occurred is separated. And the data integration unit 29 for integrating the input data D _in 1 and D _in 2 excluding the influence of the interference by the interference data separation unit 28 and generating the input data D _in to the system SYS. And data dividing means 210 for dividing the output data D _out from the system SYS into output data D _out 1 and D _out 2.

Further, the baseband processing unit 2 is configured to be shared by the two transmission / reception systems, and the reference frequency signal output means 24 for outputting the reference frequency signal S _ref having the reference frequency f _ref and the SAW analog-to-digital converted by the ADC 18. Error frequency detection means 23 for receiving an oscillator output signal LS _raw and a reference frequency signal S _ref and calculating an error frequency f _err , which is an error between the target frequency f _tgt and the frequency f _raw of the SAW oscillator output signal LS _raw ; , A correction signal generation means 25 for generating an error correction signal LS _err having an error frequency f _err , a multiplier 26 for multiplying the baseband input signal BS _in by the error correction signal LS _err , and a baseband output signal BS a multiplier 27 that multiplies _out by the error correction signal LS _err . Here, the target frequency f _tgt is a frequency expected for the SAW oscillator output signal LS _raw and is a value determined in advance according to a frequency band in which transmission / reception is performed by the wireless transmission / reception circuit. Ideally, the frequency f _raw of the SAW oscillator output signal LS _raw and the target frequency f _tgt are equal, but in reality, the SAW oscillator 11 is affected by an external impact, a temperature change, and the like, so that an error occurs.

In the present embodiment, in the RF front end circuit 1, the SAW oscillator output signal LS _raw , which is the output of the SAW oscillator 11, is not used for frequency stabilization but is used as it is as the output of the local oscillator. Then, in the baseband processing unit 2, the correction using the error correction signal LS _err is performed before the demodulation process and after the modulation process, whereby the frequency f _raw and the target frequency f of the SAW oscillator output signal LS _raw are obtained. An error generated during _tgt is corrected.

The calculation of the error between the frequency f _{raw of the} SAW oscillator output signal LS _raw and the target frequency f _tgt and the generation of the error correction signal LS _err are similar to the processing described with reference to FIG. This is performed by the frequency detection means 23. The calculated error correction signal LS _err is used for correction processing in demodulation processing and modulation processing described later.

FIG. 11 is a flowchart illustrating a process of demodulating and integrating the received signals RS _rcv 1 and RS _rcv 2 to obtain input data D _in by the radio transmission / reception circuit according to the present embodiment. First, in step S71, the first transmission / reception system is demodulated into the input data D _in 1 of the reception signal RS _rcv 1 received by the antenna ANT1. This is the same as the processing described with reference to FIG. 9 in the second embodiment, using the bandpass filter 171, the multiplier 131, the ADC 151, the multiplier 261, and the demodulation means 211.

In the demodulation processing here, as described with reference to FIG. 9, the baseband input signal BS _in 1 input to the baseband processing unit 2 is multiplied by the error correction signal LS _err . Later, demodulation by the demodulation means 211 is performed. As a result, the input data D _in 1 can be generated without being affected by the error between the frequency f _raw of the SAW oscillator output signal LS _raw and the target frequency f _tgt .

In step S72, similarly to the second transmission / reception system, the demodulation process of the received signal RS _rcv 2 received by the antenna ANT2 to the input data D _in 2 is similarly performed by the bandpass filter 172, the multiplier 132, the ADC 152, and the multiplier 261. , Using the demodulation means 212.

In step S73, the input data D _in 1 and input data D _in 2 generated as described above are input to the interference data separation means 28 to eliminate the influence of interference by the antennas ANT1 and ANT2, and in step S74. Data integration by the data integration unit 29 is performed, and input data D _in to the system SYS is output.

FIG. 12 is a flowchart showing a process of obtaining the transmission signals RS _snd 1 and RS _snd 2 by dividing and modulating the output data D _out by the radio transmission / reception circuit according to the present embodiment. First, in step S81, the data dividing unit 210 outputs the output data _Dout from the first transmission / reception system to the output data _Dout1 and the output data _Dout2 to output from the second transmission / reception system. And split.

In step S82, the first transmission / reception system modulates the output data D _out 1 into the transmission signal RS _snd 1 by the antenna ANT1. In this case, the same processing as that described with reference to FIG. 10 in the second embodiment is performed using the modulation unit 221, the multiplier 271, the DAC 161, and the multiplier 141.

In the modulation processing here, as described with reference to FIG. 10, after the modulation of the output data D _out 2 by the modulation unit 222, multiplication by the error correction signal LS _err is performed. it includes components for pre SAW oscillator output signal _{LS raw} frequency _{f raw} and error between the target frequency _{f tgt} corrected baseband output signals _{BS out.} This cancels the error when multiplying the baseband output signal BS _out and the SAW oscillator output signal LS _raw as the output of the local oscillator.

In step S83, for the second transmission / reception system, the modulation processing of the output data D _out 2 to the transmission signal RS _out 2 from the antenna ANT2 is similarly performed using the modulation means 222, the multiplier 272, the DAC 162, and the multiplier 142. Do it.

  The reception process as shown in FIG. 11 and the transmission process as shown in FIG. 12 can be performed by switching the transmission / reception selector switch SW.

  As described above, by using the radio transmission / reception circuit according to the present embodiment, the communication capacity can be increased by using a plurality of transmission / reception systems in addition to the increase in communication capacity by using the high spectral purity of the SAW oscillator. Can be planned.

  In the present embodiment, a configuration having two transmission / reception systems has been exemplified, but a configuration including more transmission / reception systems can be used to increase the communication capacity.

  Also in this embodiment, the system SYS may be an arbitrary system that requests transmission / reception of data by wireless communication, and the wireless transmission / reception circuit according to this embodiment is a terminal device such as a mobile phone or a smartphone terminal. To equipment such as a mobile phone or other base station, can be used for various wireless communication devices.

  Alternatively, the modulation means 221 and 222 may control the phase and control the direction, distance, and the like of transmitting radio waves from the antennas ANT1 and ANT2. With such a configuration, even when the radio transmission / reception circuit according to the present embodiment is applied to a base station facility such as a mobile phone, radio waves can be more effectively conveyed.

1 RF Front End Circuit 11 SAW Oscillator 12 Phase Synchronization Circuit 121 ADC
122 DSP
122a Error frequency detection means 122b Correction signal generation means 123 Reference frequency output means 124 DAC
125 Multipliers 13, 131, 132, 14, 141, 142 Multipliers 15, 151, 152 ADC
16, 161, 162 DAC
17, 171, 172 Band pass filter 18 ADC
2 Baseband processing section 21 Demodulating means 22 Modulating means 23 Error frequency detecting means 24 Reference frequency signal output means 25 Correction signal generating means 26, 261, 262, 27, 271, 272 Multiplier 28 Interference data separating means 29 Data integrating means 210 Data division means ANT, ANT1, ANT2 Antenna SW, SW1, SW2 Transmission / reception changeover switch SYS System LS _raw SAW oscillator output signal S _ref Reference frequency signal LS _err Error correction signal LS _out Local oscillator output signal RS _rcv , RS _rcv 1, RS _rcv 2 received signal RS _snd , RS _snd 1, RS _snd 2 transmitted signal BS _in , BS _in 1, BS _in 2 Baseband input signal BS _out , BS _out 1, BS _out 2 Baseband output signal D _in , D _{i n 1, D in} 2 input data _{D out, D out 1, D} out 2 output data

Claims (14)

A phase synchronization circuit that corrects an error between the frequency of the output signal of the oscillator and a predetermined target frequency,
An ADC for analog-to-digital conversion of the output signal;
A reference frequency output means for outputting a reference frequency signal;
Error frequency detection means for receiving an input of the analog-digital converted output signal and the reference frequency signal and calculating an error between the frequency of the output signal and the target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
DAC that performs digital-analog conversion of the error correction signal;
A phase synchronization circuit comprising: a multiplier that multiplies the output signal and the error correction signal that has been digital-analog converted.   The phase locked loop circuit according to claim 1, wherein an output signal of a SAW oscillator is used as the output signal. An RF front-end circuit that converts a received signal received by an antenna into a baseband input signal and converts a baseband output signal into a transmission signal transmitted by the antenna,
A local oscillator,
A phase synchronization circuit that performs phase synchronization of the output signal of the local oscillator;
A first multiplier for multiplying the received signal by the output signal of the phase locked loop and outputting the baseband input signal;
A second multiplier that multiplies the baseband output signal and the output signal of the phase synchronization circuit and outputs the transmission signal;
The phase synchronization circuit is
An ADC for analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
Error frequency detection means for receiving an output of the analog-digital converted output signal of the local oscillator and the reference frequency signal and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generating means for generating a frequency correction signal based on the error;
A DAC for digital-analog conversion of the frequency correction signal;
An RF front-end circuit, comprising: a multiplier that multiplies the output signal of the local oscillator by the frequency correction signal that has been digital-analog converted.   The RF front end circuit according to claim 3, wherein the local oscillator is a SAW oscillator.   A portable wireless communication terminal device comprising the RF front-end circuit according to claim 3. A radio transmission / reception circuit that performs conversion of input signals received by an antenna into input data and conversion of output data into transmission signals transmitted from the antenna,
A local oscillator,
A first ADC that performs analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
An error frequency detection means for receiving an input of the output signal of the local oscillator and the reference frequency signal which have been analog-digital converted, and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
A first multiplier that multiplies the output signal of the local oscillator and the received signal to generate a baseband input signal;
A second ADC that performs analog-to-digital conversion of the baseband input signal;
A second multiplier that multiplies the analog-to-digital converted baseband input signal and the error correction signal;
Demodulation means for demodulating the output signal of the second multiplier and outputting the output data;
Modulation means for modulating the output data;
A third multiplier for multiplying the output signal of the modulation means by the error correction signal and outputting a baseband output signal;
A DAC for digital-analog conversion of the baseband output signal;
A wireless transmission / reception circuit comprising: a fourth multiplier that multiplies the digital-analog converted baseband output signal and the output signal of the local oscillator to generate a transmission signal.   The wireless transmission / reception circuit according to claim 6, wherein the local oscillator is a SAW oscillator.   A portable wireless communication terminal apparatus comprising the wireless transmission / reception circuit according to claim 6. A first received signal received by the first antenna and a second received signal received by the second antenna are converted into input data, and output data is transmitted from the first antenna; A wireless transmission / reception circuit that performs conversion to a second transmission signal transmitted from the second antenna,
A local oscillator,
A first ADC that performs analog-to-digital conversion of the output signal of the local oscillator;
A reference frequency output means for outputting a reference frequency signal;
An error frequency detection means for receiving an input of the output signal of the local oscillator and the reference frequency signal which have been analog-digital converted, and calculating an error between the frequency of the output signal of the local oscillator and a predetermined target frequency;
Correction signal generation means for generating an error correction signal based on the error; and
A first multiplier that multiplies the output signal of the local oscillator and the first received signal to generate a first baseband input signal;
A second multiplier that multiplies the output signal of the local oscillator and the second received signal to generate a second baseband input signal;
A second ADC that performs analog-to-digital conversion of the first baseband input signal;
A third ADC that performs analog-to-digital conversion of the second baseband input signal;
A third multiplier for multiplying the first baseband input signal that has been analog-to-digital converted by the error correction signal;
A fourth multiplier that multiplies the second baseband input signal that has been analog-to-digital converted by the error correction signal;
First demodulation means for demodulating the output signal of the third multiplier and outputting first demodulated data;
Second demodulating means for demodulating the output signal of the fourth multiplier and outputting second demodulated data;
Data integration means for integrating the first demodulated data and the second demodulated data to generate the output data;
Data dividing means for dividing the output data into first modulation target data and second modulation target data;
First modulation means for modulating the first modulation target data;
Second modulation means for modulating the second data to be modulated;
A fifth multiplier for multiplying the output signal of the first modulation means by the error correction signal and outputting a first baseband output signal;
A sixth multiplier for multiplying the output signal of the second modulation means by the error correction signal and outputting a second baseband output signal;
A first DAC that performs digital-to-analog conversion of the first baseband output signal;
A second DAC that performs digital-to-analog conversion of the second baseband output signal;
A seventh multiplier that multiplies the first baseband output signal that has been digital-to-analog converted by the output signal of the local oscillator to generate the first transmission signal;
And an eighth multiplier that multiplies the second baseband output signal that has been digital-analog converted by the output signal of the local oscillator and generates the second transmission signal. , Wireless transceiver circuit.   The wireless transmission / reception circuit according to claim 9, wherein the local oscillator is a SAW oscillator.   A portable wireless communication terminal apparatus comprising the wireless transmission / reception circuit according to claim 9. A frequency stabilization method for correcting an error between a frequency of an output signal of an oscillator and a predetermined target frequency,
Performing analog-to-digital conversion of the output signal;
Comparing the analog-digital converted frequency of the output signal with a reference frequency and calculating the error;
Generating an error correction signal for correcting the error;
Performing digital-analog conversion of the error correction signal;
Multiplying the output signal by the digital-analog converted error correction signal, and a method for stabilizing the frequency. A method of demodulating a radio reception signal that converts reception signal received by an antenna into input data,
Multiplying the received signal and the output signal of the local oscillator to generate a baseband input signal;
Performing analog-to-digital conversion of the baseband input signal;
Performing analog-to-digital conversion of the output signal of the local oscillator;
Calculating an error between the frequency of the local oscillator output signal and a predetermined target frequency from the analog-digital converted output signal of the local oscillator;
Generating an error correction signal based on the error; multiplying the analog-to-digital converted baseband input signal by the error correction signal;
Demodulating a signal obtained by multiplication of the baseband input signal and the error correction signal, and outputting the input data. A radio transmission signal modulation method for converting output data into a transmission signal to be transmitted from an antenna,
Performing analog-to-digital conversion of the output signal of the local oscillator;
Calculating an error between the frequency of the local oscillator output signal and a predetermined target frequency from the analog-digital converted output signal of the local oscillator;
Generating an error correction signal based on the error; modulating the output data;
Multiplying the signal obtained by modulating the output data and the error correction signal, and outputting a baseband output signal;
Performing digital-analog conversion of the baseband output signal;
And a step of multiplying the digital-analog converted baseband output signal by the output signal of the local oscillator to generate the transmission signal.