Transmitter, mobile communication terminal, method of transmission by transmitter, and program

Abstract

To provide a transmitter, a mobile communication terminal, a transmission method by the transmitter, and a program that can suppress an increase in a circuit scale.SOLUTION: A transmitter according to an embodiment includes a phase modulator that modulates the phase of each of two series of digital signals, a selector that selects and outputs one of the two series of signals that have been phase modulated while periodically switching, and an amplifier that amplifies and outputs the output signal of the selector.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a transmitter, a mobile communication terminal, a transmission method by the transmitter, and a program.

Background Art

[0002] In recent years, the development of miniaturization of mobile communication devices has been progressing. Technologies related to mobile communication devices are disclosed in, for example, Patent Document 1. The transmitter of the mobile satellite communication terminal disclosed in Patent Document 1 includes a Nyquist filter that removes high-frequency components of two series of orthogonal data, an envelope equalizer that makes the distance from the origin of the envelope when each of the two series of outputs of the Nyquist filter is displayed on an orthogonal axis constant, a phase modulator that performs phase modulation on the two series of output signals of the envelope equalizer, and a high-power amplifier that converts the output signal of the phase modulator into a high-frequency signal and amplifies it with high power.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the transmitter disclosed in Patent Document 1, the high-power amplifier amplifies the output signal of the phase modulator without removing the signal components of unnecessary wavelengths included in the output signal of the phase modulator. Therefore, in this transmitter, a separate circuit configuration for processing the signal components of unnecessary wavelengths is required, and the circuit configuration becomes complicated, resulting in an increase in the circuit scale.

[0005] One object of the present disclosure is to provide a transmitter, a mobile communication terminal, a transmission method by the transmitter, and a program that solve the above-described problems.

Means for Solving the Problems

[0006] A transmitter according to a first aspect of this disclosure includes a phase modulator that performs phase modulation on each of two digital signals, a selector that periodically switches between and outputs one of the two phase-modulated signals, and an amplifier that amplifies and outputs the output signal of the selector.

[0007] A transmission method by a transmitter according to a second aspect of this disclosure involves phase modulation of each of two digital signals, periodically switching between and selecting one of the two phase-modulated signals to output, and amplifying and outputting the selected signal.

[0008] A program according to a third aspect of this disclosure causes a computer to perform the following processes: a process of performing phase modulation on each of two digital signals; a process of periodically switching between and selecting one of the two phase-modulated signals and outputting it; and a process of amplifying the selected and outputted signal and outputting it. [Effects of the Invention]

[0009] This disclosure provides a transmitter, a mobile communication terminal, a transmission method using the transmitter, and a program that can suppress an increase in circuit size. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram illustrating the overview of the transmitter according to Embodiment 1. [Figure 2] This is a block diagram showing a specific configuration example of the transmitter according to Embodiment 1. [Figure 3] This is a block diagram showing an example configuration of an AD converter provided in the transmitter according to Embodiment 1. [Figure 4] This is a block diagram showing an example configuration of a phase modulator provided in the transmitter according to Embodiment 1. [Figure 5] This is a waveform diagram of the signal relating to the in-phase channel of the phase modulator provided in the transmitter according to Embodiment 1. [Figure 6] This is a waveform diagram of the signal relating to the orthogonal channel of the phase modulator provided in the transmitter according to Embodiment 1. [Figure 7] This is a waveform diagram of the input and output signals of a selector provided in the transmitter according to Embodiment 1. [Figure 8] This is a flowchart showing the operation of the transmitter according to Embodiment 1. [Modes for carrying out the invention]

[0011] The embodiments will be described below with reference to the drawings. Note that the drawings are simplified, and the technical scope of the embodiments should not be narrowly interpreted based on their depiction. Furthermore, the same elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0012] In the following embodiments, when necessary for convenience, the description will be divided into multiple sections or embodiments. However, unless otherwise specified, they are not unrelated, and one may be a modification, application, detailed explanation, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including number, numerical value, quantity, range, etc.), unless otherwise specified or clearly limited to a specific number in principle, it is not limited to that specific number, and may be greater than or less than that specific number.

[0013] Furthermore, in the following embodiments, the components (including operation steps, etc.) are not necessarily essential unless specifically stated or considered to be clearly essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of the components, etc., it shall include those that substantially approximate or resemble the shape, etc., unless specifically stated or considered to be not in principle. The same applies to the numbers, etc. (including the number of items, numerical values, quantities, ranges, etc.) mentioned above.

[0014] <Embodiment 1> FIG. 1 is a block diagram showing an overview of the transmitter 100 according to Embodiment 1. The transmitter 100 according to the present embodiment is mounted on, for example, a mobile communication terminal and transmits a signal to an external device such as a base station device. Here, the mobile communication terminal is a movable communication terminal, such as a portable terminal such as a smartphone or a tablet terminal, or a wearable terminal. Here, the transmitter 100 removes signal components of unnecessary wavelengths included in the output signal of the phase modulator using a selector, and then amplifies the output signal of the phase modulator from which the signal components of unnecessary wavelengths have been removed using a power amplifier. Thereby, in the transmitter 100 according to the present embodiment, the circuit configuration for processing the signal components of unnecessary wavelengths generated in the phase modulator is simplified, so an increase in the circuit scale is suppressed. Also, thereby, an increase in cost is suppressed. This will be specifically described below.

[0015] As shown in FIG. 1, the transmitter 100 includes at least a phase modulator 150, a selector 160, and a power amplifier 170.

[0016] The phase modulator 150 performs phase modulation on each of the two series of digital signals Di3 and Dq3 and outputs two series of high-frequency signals Di4 and Dq4. In other words, the phase modulator 150 up-converts the frequencies of each of the two series of digital signals Di3 and Dq3 to an arbitrary frequency and outputs two series of high-frequency signals Di4 and Dq4.

[0017] The selector 160 selects one of the two series of high-frequency signals Di4 and Dq4 while periodically switching and outputs it as the high-frequency signal D5. Specifically, the selector 160 selects one of the two series of high-frequency signals Di4 and Dq4 while switching at a period Tc corresponding to the oscillation frequency fc of the local oscillation signal used for phase modulation by the phase modulator 150 and outputs it as the high-frequency signal D5. Thereby, signal components (spurious harmonics) of unnecessary wavelengths included in each of the high-frequency signals Di4 and Dq4 are removed.

[0018] The power amplifier 170 amplifies the high-frequency signal D5 output from the selector 160 and outputs it as a high-frequency signal D6. The high-frequency signal D6 is radiated to the outside via an antenna, for example, after noise components are removed.

[0019] As described above, the transmitter 100 according to the present embodiment removes signal components of unnecessary wavelengths included in the output signals Di4 and Dq4 of the phase modulator 150 using the selector 160, and then amplifies the output signal D5 of the selector 160 from which the signal components of unnecessary wavelengths have been removed using the power amplifier 170. Thereby, in the transmitter 100 according to the present embodiment, the circuit configuration for processing signal components of unnecessary wavelengths generated in the phase modulator 150 is simplified, so an increase in the circuit scale is suppressed. Also, thereby, an increase in cost is suppressed.

[0020] Subsequently, a more specific configuration of the transmitter 100 will be described using FIG. 2. FIG. 2 is a block diagram showing a specific configuration example of the transmitter 100 as a transmitter 101. [[ID=ll]]

[0021] As shown in FIG. 2, the transmitter 101 further includes a data generation unit 110, a baseband signal modulator 120, a Nyquist filter 130, an analog-to-digital converter (AD converter) 140, and a filter 180, as compared with the transmitter 100. That is, the transmitter 101 includes a data generation unit 110, a baseband signal modulator 120, a Nyquist filter 130, an AD converter 140, a phase modulator 150, a selector 160, a power amplifier 170, and a filter 180.

[0022] The data generation unit 110 generates two series of random data Di0 and Dq0 for the in-phase channel and the quadrature channel. The baseband signal modulator (BB signal modulator) 120 modulates each of the two series of random data Di0 and Dq0 into baseband signals Di1 and Dq1. The Nyquist filter 130 samples each of the two series of baseband signals (BB signals) Di1 and Dq1 and outputs two series of signals Di2 and Dq2.

[0023] The AD converter 140 digitally converts each of the two sampled signal sequences, Di2 and Dq2, to output two digital signals, Di3 and Dq3.

[0024] (Specific configuration example of AD converter 140) Figure 3 is a block diagram showing a specific configuration example of the AD converter 140. Referring to Figure 3, the AD converter 140 is a so-called ΔΣ AD converter and comprises subtractors 141, 145, integrators 142, 146, quantizers 143, 147, and 1-bit digital-to-analog converters (1-bit DA converters or 1-bit DA converters (1-bit DACs)) 144, 148.

[0025] The subtractor 141 outputs a difference signal representing the difference between the in-phase channel analog signal Di2 and the analog feedback signal output from the 1-bit DA converter 144. The integrator 142 integrates the output signal of the subtractor 141 and outputs it. The quantizer 143 quantizes the output signal of the integrator 142 and outputs it as a digital signal Di3. The 1-bit DA converter 144 converts the digital signal Di3 to analog and outputs it as the aforementioned feedback signal. The subtractor 145 outputs a difference signal representing the difference between the orthogonal channel analog signal Dq2 and the analog feedback signal output from the 1-bit DA converter 148. The integrator 146 integrates the output signal of the subtractor 145 and outputs it. The quantizer 147 quantizes the output signal of the integrator 146 and outputs it as a digital signal Dq3. The 1-bit DA converter 148 converts the digital signal Dq3 to analog and outputs it as the aforementioned feedback signal.

[0026] Note that the AD converter 140 is not limited to the ΔΣ AD converter configuration shown in Figure 3, and can be appropriately changed to any AD converter configuration. However, it is preferable that the AD converter 140 is a pulse width modulation type AD converter, such as the ΔΣ AD converter shown in Figure 3 or a Δ modulation type AD converter.

[0027] The phase modulator 150 modulates the phase of each of the two digital signals Di3 and Dq3, and outputs two high-frequency signals Di4 and Dq4. In other words, the phase modulator 150 upconverts the frequencies of each of the two digital signals Di3 and Dq3 to an arbitrary frequency and outputs two high-frequency signals Di4 and Dq4.

[0028] (Specific example configuration of phase modulator 150) Figure 4 is a block diagram showing a specific configuration example of the phase modulator 150. Referring to Figure 4, the phase modulator 150 is a so-called 1-bit phase modulator and comprises a local oscillator 151, a mixer 152, and a mixer 153.

[0029] The local oscillator 151 generates a local oscillation signal LOi, which is a square wave with a predetermined frequency fc, and a local oscillation signal LOq that is orthogonal to the local oscillation signal LOi (i.e., a local oscillation signal LOq that is 90 degrees out of phase with the local oscillation signal LOi).

[0030] Mixer 152 uses the local oscillator signal LOi to phase-modulate the common-mode channel digital signal Di3 and outputs it as a high-frequency signal Di4. In other words, mixer 152 mixes the common-mode channel digital signal Di3 with the local oscillator signal LOi to upconvert the frequency of the digital signal Di3 to an arbitrary frequency and outputs it as a high-frequency signal Di4. Mixer 153 uses the local oscillator signal LOq to phase-modulate the quadrature channel digital signal Dq3 and outputs it as a high-frequency signal Dq4. In other words, mixer 153 mixes the quadrature channel digital signal Dq3 with the local oscillator signal LOq to upconvert the frequency of the digital signal Dq3 to an arbitrary frequency and outputs it as a high-frequency signal Dq4.

[0031] Note that the phase modulator 150 is not limited to the configuration of a 1-bit phase modulator as shown in Figure 4, and can be appropriately changed to any phase modulator configuration. For example, the phase modulator 150 may be a PLL modulator. Alternatively, in the configuration in which the AD converter 140 is omitted from the transmitters 100 and 101, the phase modulator 150 may be configured to perform phase modulation of the analog signal of the in-phase channel and the analog signal of the quadrature channel, respectively, instead of the in-phase channel digital signal Di3 and the quadrature channel digital signal Dq3. However, the efficiency of the subsequent power amplifier 170 is better when the phase modulator 150 is configured to perform phase modulation of the digital signal than when it is configured to perform phase modulation of the analog signal. Therefore, it is preferable that the phase modulator 150 is configured as a 1-bit phase modulator as shown in Figure 4.

[0032] Selector 160 periodically switches between two high-frequency signals, Di4 and Dq4, and outputs them as high-frequency signal D5. Specifically, selector 160 switches between two high-frequency signals, Di4 and Dq4, at a period Tc corresponding to the oscillation frequencies fc of the local oscillator signals LOi and LOq, and outputs them as high-frequency signal D5.

[0033] Here, the period Tc is preferably n / fc, where n is an even number greater than or equal to 2. This removes at least a portion of the unwanted wavelength signal components contained in each of the high-frequency signals Di4 and Dq4, thereby simplifying the circuit configuration for processing these unwanted wavelength signal components. In particular, the period Tc is preferably 2 / fc. This removes the unwanted wavelength signal components contained in each of the high-frequency signals Di4 and Dq4, thereby further simplifying the circuit configuration for processing these unwanted wavelength signal components.

[0034] The mechanism for removing unwanted wavelength signal components from the high-frequency signals Di4 and Dq4 will be explained below using Figures 5 to 7. Figure 5 is a waveform diagram of the signal for the common-mode channel of the phase modulator 150. Figure 6 is a waveform diagram of the signal for the quadrature channel of the phase modulator 150. Figure 7 is a waveform diagram of the input and output signals of the selector 160. In the examples of Figures 5 to 7, the period Tc = 2 / fc.

[0035] First, referring to Figure 5, in the phase modulator 150, the mixer 152 mixes the in-phase channel digital signal Di3 with the local oscillator signal LOi, which is a square wave with a predetermined frequency fc, thereby upconverting the frequency of the digital signal Di3 to an arbitrary frequency and outputting it as a high-frequency signal Di4.

[0036] Next, referring to Figure 6, in the phase modulator 150, the mixer 153 mixes the orthogonal channel digital signal Dq3 with the local oscillator signal LOi and the local oscillator signal LOq which is orthogonal to the local oscillator signal LOi, thereby upconverting the frequency of the digital signal Dq3 to an arbitrary frequency and outputting it as a high-frequency signal Dq4.

[0037] Next, referring to Figure 7, the selector 160 selects one of the two high-frequency signals Di4 and Dq4 output from the phase modulator 150 based on the switching signal SEL and outputs it as high-frequency signal D5. Specifically, the selector 160 selects the in-phase channel high-frequency signal Di4 when the signal level of the switching signal SEL is at a high level (H level), and selects the quadrature channel high-frequency signal Dq4 when the signal level of the switching signal SEL is at a low level (L level), and outputs it as high-frequency signal D5. The signal level of the switching signal SEL changes with a period Tc of 2 / fc. As a result, in the example in Figure 7, the signal components represented by the dashed lines in each of the high-frequency signals Di4 and Dq4 are removed as unwanted wavelength signal components and output as high-frequency signal D5. Note that the waveform diagrams shown in Figures 5 to 7 are merely examples and may change depending on the content and settings of the transmitted signal.

[0038] The power amplifier 170 amplifies the high-frequency signal D5 output from the selector 160 and outputs it as high-frequency signal D6. The filter 180 removes the noise component from the high-frequency signal D6 and outputs it as high-frequency signal D7. In other words, the filter 180 band-limits the high-frequency signal D6 and outputs it as high-frequency signal D7. The high-frequency signal D7 is emitted to the outside via the antenna.

[0039] (Operation of Transmitter 101) Next, we will explain the operation of the transmitter 101 using Figure 8. Figure 8 is a flowchart illustrating the operation of the transmitter 101.

[0040] First, the transmitter 101 is activated by starting the mobile communication terminal (step S101).

[0041] Subsequently, the transmitter 101 uses the data generation unit 110 to generate two sequences of random data Di0 and Dq0, one for the in-phase channel and the other for the orthogonal channel (step S102).

[0042] Subsequently, the transmitter 101 modulates the two sequences of random data, Di0 and Dq0, into baseband signals Di1 and Dq1 using the baseband signal modulator 120 (step S103).

[0043] Subsequently, the transmitter 101 uses the Nyquist filter 130 to sample each of the two baseband signals Di1 and Dq1, and outputs two signals Di2 and Dq2 (step S104).

[0044] Subsequently, the transmitter 101 uses the AD converter 140 to digitally convert each of the two sampled signal sequences Di2 and Dq2 to output two digital signals Di3 and Dq3 (step S105).

[0045] Subsequently, the transmitter 101 uses the phase modulator 150 to perform phase modulation on each of the two digital signals Di3 and Dq3, and outputs two high-frequency signals Di4 and Dq4. In other words, the transmitter 101 uses the phase modulator 150 to upconvert the frequencies of each of the two digital signals Di3 and Dq3 to any frequency suitable for transmission, and outputs two high-frequency signals Di4 and Dq4 (step S106).

[0046] Subsequently, the transmitter 101 uses the selector 160 to periodically select one of the two high-frequency signals Di4 and Dq4 and outputs it as the high-frequency signal D5 (step S107).

[0047] Subsequently, the transmitter 101 uses the power amplifier 170 to amplify the power of the high-frequency signal D5 until it reaches a transmittable power, and outputs it as the high-frequency signal D6 (step S108).

[0048] Subsequently, the transmitter 101 uses the filter 180 to remove noise components contained in the high-frequency signal D6 and outputs it as the high-frequency signal D7 (step S109).

[0049] Subsequently, the transmitter 101 transmits the high-frequency signal D7 to the outside via the antenna (step S110).

[0050] As described above, the transmitter according to this embodiment removes unwanted wavelength signal components from the output signal of the phase modulator using a selector, and then amplifies the output signal of the phase modulator from which the unwanted wavelength signal components have been removed using a power amplifier. As a result, the circuit configuration for processing unwanted wavelength signal components generated in the phase modulator is simplified in the transmitter according to this embodiment, thereby suppressing an increase in circuit size. Furthermore, this also suppresses an increase in cost.

[0051] In this embodiment, the case in which the transmitter 100 or transmitter 101 is mounted on a mobile communication terminal was described as an example, but it is not limited to this, and can be mounted on any communication device where miniaturization is required, such as base station equipment.

[0052] Furthermore, this disclosure can be implemented by having a CPU (Central Processing Unit) execute a computer program to perform some or all of the transmission processing in the transmitter.

[0053] Specifically, the program described above includes a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments when loaded into the computer. The program may be stored in a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include RAM (Random-Access Memory), ROM (Read-Only Memory), flash memory, SSD (Solid-State Drive), or other memory technologies, CD-ROM, DVD (Digital Versatile Disc), Blu-ray® disc, or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrically, optically, acoustically, or otherwise propagating signals.

[0054] Although the embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to those described above, and various design changes are possible without departing from the gist of this disclosure.

[0055] Furthermore, some or all of the above embodiments may also be described as follows, but are not limited to the following.

[0056] (Note 1) A phase modulator that modulates the phase of each of two digital signals, A selector that periodically switches between and outputs one of two phase-modulated signal sequences, An amplifier that amplifies and outputs the output signal of the selector, A transmitter equipped with [a specific feature / equipment].

[0057] (Note 2) The aforementioned phase modulator is An oscillator that generates a first oscillation signal which is a square wave of a first frequency and a second oscillation signal which is orthogonal to the first oscillation signal, A first mixer that uses the first oscillation signal to perform phase modulation on one of the two digital signals, A second mixer that uses the second oscillation signal to perform phase modulation on the other of the two signal sequences, It has, The selector selects and outputs one of the two phase-modulated signals, switching between them at a period corresponding to the first frequency. The transmitter described in Appendix 1.

[0058] (Note 3) The selector, when fc is the first frequency and n is an even number greater than or equal to 2, selects and outputs one of the two phase-modulated signals, switching between them at a period of n / fc. The transmitter described in Appendix 2.

[0059] (Note 4) The selector selects and outputs one of the two phase-modulated signals, switching between them at a period of 2 / fc. The transmitter described in Appendix 3.

[0060] (Note 5) One of the two digital signals is an in-phase channel signal, and the other of the two digital signals is an orthogonal channel signal. A transmitter as described in any one of the appendices 1 to 4.

[0061] (Note 6) The amplifier further includes a filter that removes noise components contained in the output signal of the amplifier, A transmitter as described in any one of the appendices 1 to 5.

[0062] (Note 7) A Nyquist filter that samples each of the two baseband signals, An AD converter that digitally converts each of the two sampled signals, Furthermore, The phase modulator performs phase modulation on each of the two digital signals that are the output of the AD converter. A transmitter as described in any one of the appendices 1 to 6.

[0063] (Note 8) The aforementioned AD converter is a ΔΣ AD converter. The transmitter described in Appendix 7.

[0064] (Note 9) A mobile communication terminal equipped with the transmitter described in any one of the appendices 1 to 8.

[0065] (Note 10) A base station device equipped with the transmitter described in any one of the appendices 1 to 8.

[0066] (Note 11) Performing phase modulation on each of the two digital signals, It periodically switches between and selects one of two phase-modulated signal sequences to output. The selected signal is amplified and output. A method of transmission using a transmitter.

[0067] (Note 12) The process involves performing phase modulation on each of the two digital signals, A process that periodically switches between and selects one of two phase-modulated signal sequences to output, The process involves amplifying the selected and outputted signal and then outputting it again. A program that causes a computer to execute something. [Explanation of Symbols]

[0068] 100 Transmitters 101 Transmitter 110 Data Generation Unit 120 Baseband Signal Modulator 130 Nyquist Filter 140 AD converters 141 Subtractor 142 Integrator 143 Quantizer 144 1-bit DA converter 145 Subtractor 146 Integrator 147 Quantizer 148 1-bit DA converter 150 Phase Modulator 151 Local Oscillator 152 Mixer 153 Mixer 160 Selector 170 Power Amplifier 180 filters

Claims

1. A phase modulator that modulates the phase of each of the two digital signals, A selector that periodically switches between and outputs one of two phase-modulated signal sequences, An amplifier that amplifies and outputs the output signal of the selector, Equipped with, The aforementioned phase modulator is An oscillator that generates a first oscillation signal which is a square wave of a first frequency and a second oscillation signal which is orthogonal to the first oscillation signal, A first mixer that uses the first oscillation signal to perform phase modulation on one of the two digital signals, A second mixer that uses the second oscillation signal to perform phase modulation on the other of the two digital signals, It has, The selector, with fc as the first frequency, selects and outputs one of the two phase-modulated signals by switching between them at a period of 2 / fc. Transmitter.

2. One of the two digital signals is an in-phase channel signal, and the other of the two digital signals is an orthogonal channel signal. The transmitter according to claim 1.

3. A mobile communication terminal comprising the transmitter according to claim 1 or 2.

4. The phase modulation of each of the two digital signals is performed. It periodically switches between and selects one of two phase-modulated signal sequences to output. The selected signal is amplified and output. A method of transmission using a transmitter, In the aforementioned phase modulation, Using an oscillator, a first oscillation signal, which is a rectangular wave of a first frequency, and a second oscillation signal, which is orthogonal to the first oscillation signal, are generated. In the first mixer, the phase modulation of one of the two digital signals is performed using the first oscillation signal. In the second mixer, the second oscillation signal is used to perform phase modulation on the other of the two digital signals. In the selected output of the two phase-modulated signals, If fc is the first frequency, then one of the two phase-modulated signals is selected and output while switching between them with a period of 2 / fc. A method of transmission using a transmitter.

5. The process involves performing phase modulation on each of the two digital signals, A process that periodically switches between and selects one of two phase-modulated signal sequences to output, The process involves amplifying the selected and outputted signal and then outputting it again. A program that causes a computer to execute, The process for performing the aforementioned phase modulation is: A process that uses an oscillator to generate a first oscillation signal, which is a square wave of a first frequency, and a second oscillation signal that is orthogonal to the first oscillation signal. In the first mixer, the process involves using the first oscillation signal to perform phase modulation on one of the two digital signals, In the second mixer, the second oscillation signal is used to perform phase modulation on the other of the two digital signals, It has, The process of selecting and outputting the two phase-modulated signals is as follows: If fc is the first frequency, the process includes selecting and outputting one of the two phase-modulated signals while switching between them at a period of 2 / fc. program.

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