KR20090100734A - Single side band frequency mixer and single side band signal extracting method - Google Patents

Abstract

PURPOSE: A single side band frequency mixer and a method for extracting a single side band signal are provided to remove a loss of an output signal by simplifying a circuit structure in a single side band frequency mixer of a transmitting end. CONSTITUTION: A single side band frequency mixer includes an IF(Intermediate Frequency) balun, a first phase shifter, an LO(Local Oscillation) balun, a second phase shifter, an input pass control switch, and a mixer core. The IF balun outputs an input intermediate frequency signal as two intermediate frequency signals having phase difference of 180 degree. The first phase shifter outputs the two intermediate frequency signals as four intermediate frequency signals having phase difference of 90 degree. The LO balun outputs a local oscillation signal as two local oscillation signals having phase difference of 180 degree. The second phase shifter outputs the two local oscillation signals as four local oscillation signals having phase difference of 90 degree. The input pass control switch(401) controls an output frequency from the intermediate frequency signal inputted from the first phase shifter. The mixer core mixes the intermediate frequency signal controlled by the input pass control switch to the local oscillation signal outputted from the second phase shifter.

Description

Single side band frequency mixer and single side band signal extracting method

The present invention relates to a single sideband frequency mixer in a UWB frequency generator using a wideband frequency, and more particularly, to a single sideband frequency mixer with a simplified circuit structure.

Wireless communication systems use frequencies of a certain band to transmit data. Meanwhile, as the amount of data to be transmitted using a wireless communication system increases, the frequency band also increases. This wide frequency band is called an ultra wide band (UWB), and the present invention relates to a single sideband frequency mixer in such a UWB frequency generator.

In general, in a wireless communication system, a transmitting side modulates one or more keyband information signals using one or more carrier signals, converts the information into RF signals, and a receiving side removes a carrier component and receives an intermediate frequency (IF) for the received RF signal. It converts the signal to demodulate the IF signal, or directly demodulates the RF signal without intermediate frequencies.

In amplitude modulation in which an information signal modulates the amplitude of a carrier wave, Fourier transforming the modulated signal causes frequency analysis to shift up and down by a carrier frequency to generate an upper band and a lower band having the same amount of information. The transmission of both sidebands is called double side band (DSB) modulation, and the transmission of only one sideband by removing unnecessary one sideband with a filter is called single sideband (SSB) modulation. In the case of voice or music sound, since there are few signal components in the low frequency band, communication is possible only by SSB modulation.

The carrier suppression modulator for single sideband modulation is usually a ring modulator or a balanced modulator. Since the frequency spectrum of the amplitude modulated wave is related to the signal wave, only one of the upper and lower bands needs to be sent when transmitting a signal to the counterpart. In addition, since the carrier is suppressed at the transmission output, the capacity of the transmitter may be small and power consumption may be saved. To obtain this SSB signal, the carrier is removed using a balance modulator, and then one of the upper and lower bands is selected using a band pass filter.

Conventional single sideband frequency mixers combine ω _LO + ω _IF with one mixer (Sum frequency) or ω _LO - ω _IF Only one (difference frequency) could be output.

1 is a block diagram showing a method of obtaining a desired output frequency through two conventional single sideband frequency mixers and a frequency selector. Referring to Figure 1, ω _LO generated through the local oscillator The signal is fed to the baseband by the intermediate frequency ω _IF and two different single sideband frequency mixers, ω _LO + ω _IF (Sum frequency) or ω _LO - ω _IF These frequencies are selected by means of a frequency selector that acts as a filter to filter out only the desired frequency band, whereby the signal passes through the filter to obtain only the desired frequency signal, but there is a gain attenuation of the output power. It is a disadvantage.

In addition, in the case of using a mode regulator (or phase adjuster) at a conventional frequency mixer input stage different from the above, the sum frequency and the difference frequency can be selected using the mode adjuster (or phase adjuster). The disadvantage is that it becomes large and very complex.

There are many more ways, but most of these cases have other drawbacks, such as complex circuitry or gain reduction in output power.

An object of the present invention is to solve the above problems, simplifies the circuit structure in the single-sideband frequency mixer of the transmitter stage ω _LO + ω _IF (Sum frequency) and ω _LO - ω _IF It is to provide a single sideband frequency mixer and a single sideband signal extraction method which are easy to control the output of (difference frequency) and have no loss of output signal.

To achieve the above object, the single sideband frequency mixer according to the first aspect of the present invention comprises: an IF (intermediate frequency) balun which outputs an input intermediate frequency signal as two intermediate frequency signals having a 180 ° phase difference; A first phase shifter for outputting the two intermediate frequency signals as four intermediate frequency signals having a phase difference of 90 ° each; LO (local oscillation) for outputting a local oscillation signal as two local oscillation signals having a 180 ° phase difference Balloon; A second phase shifter for outputting the two local oscillation signals as four local oscillation signals each having a phase difference of 90 °; An input path control switch capable of controlling an output frequency from an intermediate frequency signal inputted from the first phase shifter; And a mixer core for mixing the intermediate frequency signal controlled by the input path control switch and the local oscillation signal output from the second phase shifter.

Preferably, the input path control switch includes four transistors and an inverter using two transistors as one unit.

More preferably, the transistor of the input path control switch is a MOSFET. In addition, it is preferable to selectively control the frequency of the output signal by using an inverter in a path in which an intermediate frequency signal is input to the source of the MOSFET and a control signal is respectively input to the gate.

The transistor of the input path control switch is preferably a BJT or similar semiconductor.

In addition, it is preferable that the input path control switch uses a mechanical switch that controls ON / OFF through mechanical contact.

In order to achieve the above object, a single sideband signal extraction method according to the second aspect of the present invention includes a first step of outputting an input intermediate frequency signal and a local oscillation signal as two signals each having a 180 ° phase difference; A second step of outputting the two intermediate frequency signals and the two local oscillation signals of the first step as four signals having a phase difference of 90 ° each; A third step of controlling output frequencies of the four intermediate frequency signals of the second step through an input path control switch; And a fourth step of mixing the controlled signal of the third step and the local oscillation signal of the second step.

As described above, the present invention facilitates the control of the sum frequency and the difference frequency by simplifying the circuit structure by replacing a simple switch with the need to select an output frequency through a complicated circuit for the single sideband output in the UWB frequency generator. Not only this, but also low cost production is possible without loss of output signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are provided to aid the understanding of the present invention and the present invention is not limited to the following examples.

FIG. 2 is a block diagram illustrating a method of controlling an output frequency of a single sideband frequency mixer through a mode adjuster according to a conventional embodiment, wherein the mode adjuster is March 2006 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 41, NO. The circuit diagram is shown in "3 to 8 GHz Fast Hopping Frequency Synthesizer in 0.18um CMOS Technology" as listed in 3.

As shown, a mode controller 301, Gilbert cell mixers 1 and 2 302, and a local oscillator and adder 303 are provided. Input the intermediate frequency signal of the frequency mixer at the IF input terminal, select the sum frequency or the difference frequency using the mode controller, and then the Gilbert cell mixer 1 and the Gilbert cell mixer 2 receive the selected input signal and mix it with the local oscillator LO signal. In 303, the signals of the two blocks are combined to output a single sideband signal (RF signal). As shown, the mode regulator circuit diagram shows that the circuit is bulky and very complex.

3 is a diagram showing frequency bands 528 MHz apart in the frequency domain of ultra wide-band (UWB), which is an application service of the present invention. The present invention is designed to facilitate the wideband frequency output of a circuit such as a UWB frequency generator, and has a center frequency (ω ₀ ) of 3432 MHz, 3960 MHz, 4488 MHz in the frequency range of the UWB. … ± 528 MHz ( ω _IF You can selectively output both left difference frequency and right sum frequency.

4 is a block diagram of a single sideband frequency mixer according to the present invention for controlling an input signal through an input path control switch.

As shown, it includes an input path control switch 401, Gilbert cell mixers 1 and 2 402, and an adder 403. The IF input terminal inputs an intermediate frequency signal ( ω _IF ) of the frequency mixer, and the Control terminal controls so as to select two output signals of the switch 401, a "sum" signal and a "difference" signal. Gilbert cell mixer 1 402 and Gilbert cell mixer 2 402 receive the input signal controlled by the input path control switch 401 and mix it with the local oscillator LO signal, and then adds the signals of the two blocks in the adder 403. It will output a single sideband signal. When the "sum" signal is input to the Gilbert cell mixer block 402 by the control of the control terminal, ω _LO + ω _IF (sum frequency) is output; when the "difference" signal is input, ω _LO - ω _IF Outputs (difference frequency).

FIG. 5 is a detailed circuit diagram illustrating the input path control switch 401 of FIG. 4. Referring to FIG. 5, M1 and M2 transistors are input to two sources having different phases of the intermediate frequency signal IF from a source. At this time, as the switch control signal (DC voltage) supplied from the control unit of the frequency mixer is input to the gate, two IF signals are turned on and off, respectively. First, when the switch control signal " 1 " (e.g., a dc voltage of 3 V) is input to the two switch transistors M1 and M2, respectively, M2 is ON since 3 V is input to the gate, and the signal is gated through the inverter. When the input M1 is turned off, the frequency mixer inputs the IF signal passing through the M2 and outputs the difference frequency (−SSB output) of ω _LO −ω _IF . Conversely, when a signal of "0" (for example 0 V) is input as the switch control signal, M1 is turned ON and M2 is turned OFF so that the frequency mixer has a sum frequency (+ SSB of ω _LO + ω _IF) . output).

Here, the M1 and M2 transistors can be realized using not only MOSFETs, but also similar semiconductors, and other semiconductor devices capable of controlling ON / OFF, such as BJT and similar semiconductors. In addition, although the input path control switch 401 is illustrated to control ON / OFF by using a transistor in the present embodiment, any of those that can control the flow of signals ON / OFF as described above, such as a mechanical ON / OFF switch. The use of devices and instruments is possible.

6 is a block diagram showing the configuration of a single sideband frequency mixer according to an embodiment of the present invention.

As shown, the single sideband frequency mixer has an IF balun 601 and a first phase shifter 602, an input path control switch 603, a mixer core 604, an LO balun 605 and a second. Phase shifter 606.

Four IF quadrature signals must be input to the IF input terminal to remove the image frequency, so that a single sideband output is possible.In general, since the input IF signal has only one phase, the IF balun ( 601 and a first phase shifter 602 are required. Since the LO signal input at this time also requires four quadrature signals, the LO balun 605 and the second phase shifter 606 are required at the same time.

Four quadrature signals generated while passing through the IF balun 601 and the first phase shifter 602 as described above with reference to FIG. 5 while passing through the input path control switch 603 as described above. A mixer consisting of Gilbert cell mixers 1 and 2, which is input to the switch transistors M1 and M2, respectively, and outputs a difference frequency (−SSB output) with ω _LO -ω _IF and a sum frequency (+ SSB output) with ω _LO + ω _IF . The core 604 receives the input signal controlled by the switch 603 and mixes it with the local oscillator LO signal, and then combines the signals of the two blocks to output the single sideband signal.

7 is a circuit diagram showing an embodiment according to the present invention. As shown, the IF balun circuit 701, the first phase shifter circuit 702, the input path control switch circuit 703, the frequency mixer core circuit 704, the LO balun circuit 705, the second phase shift It consists of a self circuit 706 and an inverter circuit 707.

를 이용하여 각각 4개 출력신호가 전력은 같고 90˚ 위상차이가 되도록 구성하였다.In FIG. 7, the IF balun circuit 701 outputs an IF input signal as two signals having phases of 0 ° and 180 °. The IF balun circuit 701 is a circuit for outputting the two output signals using a resistor / capacitor feedback. The power is the same and the phases are designed to be 180 degrees apart. The first phase shifter circuit 702 is a circuit for outputting an input signal having a phase difference of 0 ° and 180 ° as four signals having phases of 0 °, 90 °, 180 °, and 270 °. That is, it is a circuit that causes quadrature phase shift by using a parallel connection of a resistor and a capacitor.

Each of the four output signals has the same power and 90˚ phase difference.

The LO balun circuit 705 also generates an input LO signal as two LO output signals having phases of 0 ° and 180 °, and the second phase shifter circuit 706 has four signals having a phase difference of 90 °. It is a circuit that produces. The two IF quadrature signals and the LO quadrature signals are input to the frequency mixer core circuit 704 to remove the image frequency.

The frequency mixer core circuit 704 consists of two Gilbert cell mixers. In the frequency mixer core 704, M1, M2, M3, and M4 receive and amplify four IF quadrature signals through their respective gates, while amplifying the amplified IF signals through their respective drains, M5, M6, and M7. And M8, M9 and M10, M11 and M12 as the source. The input IF quadrature signals are combined with the LO quadrature signals input to the gates of M5 and M6, M7 and M8, M9 and M10, and M11 and M12, respectively. The combined signal is output to the drains of M5 and M6, M7 and M8, M9 and M10, M11 and M12, and the outputs from the two Gilbert cell mixers are combined to produce a single sideband output signal with the final image frequency removed. .

FIG. 8 is a diagram illustrating an output of an RF signal when the frequency mixer core 704 is input as quadrature signals of different SW1 and SW2, respectively.

As shown, MOSFETs M1, M2, M3, M4 801 that amplify IF signals, MOSFETs M5, M6, M7, M8, M9, M10 that mix IF frequency ( ω _IF ) and LO frequency ( ω _LO ). , M11, M12 (802) and RF output terminal (803). Signals 1 through 4 are IF quadrature signals, and signals 5 through 8 are LO quadrature signals. Switching is shown through two different inputs, SW1 and SW2 in FIG.

Referring to the configuration diagram of FIG. 8 with reference to FIG. 7, when the SW input signal of FIG. 7 is applied at " 1 " (dc voltage: 3 V) like the control signal of FIG. 5, SW2 of FIG. OFF. At this time, the transistors M20, M22, M24, and M26 of FIG. 7 are turned on, and the IF quadrature signals are inputted through the M20, M22, M24, and M26. On the contrary, when the SW input signal of FIG. 7 is applied at "0" (dc voltage: 0 V), SW1 of FIG. 8 is ON and SW2 is OFF. At this time, the transistors M19, M21, M23, and M25 in FIG. 7 are turned on, and the IF quadrature signals are input through M19, M21, M23, and M25. Referring to FIG. 8 together with the above description, the IF quadrature signals are input to M19, M21, M23, and M25 by SW1. At this time, the transistors turned on by the LO switching signal are M5, M8, M10, and M11.

FIG. 9 is a graph illustrating an interval in which each quadrature LO signal is turned on when the LO signal is input from the local oscillator on a time axis. In FIG. 8, the IF signal input is continuously input through the gates of M1 to M4 during the periodic sinusoidal signal due to the small power of the signal. On the other hand, the LO signal input increases the power of the signal. As the power is large, the LO signal has a large difference between the maximum and minimum points of the sine wave period. Since the sinusoidal LO signal having a large power change is input to the gate of the transistor, a section in which the transistor is turned ON / OFF is formed by the LO periodic signal. Here, since the LO signals are input as four signals having a phase difference of 90 ° each, four ON sections are generated as shown in FIG. 9.

Referring to FIG. 9, the "ON interval 1" where the signals cos ω ₂ t and cos ( ω ₂ t + 90 °) is turned on, cos ( ω ₂ t + 90 °) and cos ( ω ₂ t + 180 °) "ON interval 2" turned on, cos ( ω ₂ t + 180˚) and cos ( ω ₂ t + 270˚) turned on "ON interval 3" and cos ( ω ₂ t + 270˚) and cos ω ₂ t There is an "ON segment 4" in which is turned on. The transistors M5, M8, M10, and M11 are transistors turned on by " ON interval 1 " in which the sinusoidal cos ω ₂ t and cos ( ω ₂ t + 90 °) of the LO switching signal simultaneously exhibit high positive values.

Therefore, referring to FIG. 8 and FIG. 9 together, only the "ON section 1" will be described.

M5 and M11 of the transistors M5, M8, M10, and M11 turned on in the "ON section 1" fall to ground, and the transistors connected to the RF output terminals are M8 and M10. At this time, IF signal frequencies of M2 and M3 by SW1 ON are mixed with LO frequency through M8 and M10. The IF signal and the LO signal mixed by the M8 and M10 transistors are calculated by Equation 1 below.

In Equation 1, IF signal frequencies cos ( ω ₁ t + 180 °) and cos ( ω ₁ t + 90 °) of M2 and M3 by SW1 ON are respectively represented by signals 8 and 5 of " ON interval 1 " Multiply. Therefore, the output signal has a sum frequency of ω ₂ + ω ₁ as shown in Equation 1 above.

In FIG. 8, the IF quadrature signals are input to M20, M22, M24, and M26 by SW2, and the transistors turned on by the LO switching signal are M5, M8, M10, and M11 by " ON interval 1 ". The transistors connected to the RF output terminals are M8 and M10. At this time, IF signals of M2 and M3 by SW2 ON are mixed with LO signals through M8 and M10. The IF signal and the LO signal mixed by the M8 and M10 transistors are calculated as in Equation 2 below.

As shown in Equation 2, the output frequency has a difference frequency of ω _2- ω ₁ . It can be seen that the sum frequency output by SW1 and the difference frequency output by SW2 can be selectively controlled by controlling the voltage input to the input path control switch circuit 703 to ON / OFF.

FIG. 10 is a graph showing that when the SW1 signal is input to the IF terminal in the switch circuit of FIG. 7, ω _LO + ω _IF frequencies are output. FIG. 11 is a ω _LO- ω _IF frequency output when the SW2 signal is input. Is a graph showing

Referring to Figure 10, the LO frequency is set to 8.5 GHz and the simulation results, the desired frequency signal ω _LO + ω _IF 9028 MHz (8500 + 528 MHz) signals are video frequency signals ω _LO - ω _IF It outputs approximately 34 dB more power than the 7972 MHz (8500-528 MHz) signal. Similarly in Fig. 11, the LO frequency is set to 8.5 GHz, and the simulation results show that the desired frequency signal ω _LO - ω _IF sign 7972 MHz (8500-528 MHz) signal is video frequency signal ω _LO + ω _IF It can be seen that the output is approximately 33 dB more than the 9028 MHz (8500 + 528 MHz) signal. As a result of FIG. 10 and FIG. 11, it can be seen that the image frequency is almost 99.9% removed.

FIG. 12 illustrates an RF output signal ( ω _LO + ω _IF ) and an image frequency signal ( ω _LO − ω ) when the SW1 signal is input from the IF stage in the switch circuit of FIG. 7 to change the frequency of the LO signal from 3 to 10 GHz. FIG. 13 is a graph showing _IF ), and FIG. 13 shows the RF output signal ( ω _LO - ω _IF ) and the image frequency signal ( ω _LO + ω _IF ) when the SW2 signal is input from the IF stage in the same manner as in FIG. 12. The graph shown.

Referring to FIGS. 12 and 13, the broadband performance can be examined by simulating whether the present invention is applicable in the UWB frequency band, and the image frequency rejection ratio (RF signal power / video frequency signal power) in the entire frequency band of 3 to 10 GHz. It is shown that the value of 30 dB or more, through which the image frequency is almost eliminated.

FIG. 14 is a diagram illustrating RF signal power ( ω _LO + ω _IF ) − image frequency signal power ( ω ) when the SW1 signal is input at the IF stage and the frequency of the LO signal changes from 3 to 10 GHz in the embodiment according to the present invention. _LO - ω _IF ) "is a graph showing the image-rejection ratio of the value," Fig. 15 is the same as in Fig. 14, when the SW2 signal is input from the IF stage, "RF signal power ( ω _LO - ω _IF )-is a graph showing the image-rejection ratio which is the value of the image frequency signal power ( ω _LO + ω _IF ) ".

Referring to FIGS. 14 and 15, similar to the results of FIGS. 12 and 13, it is confirmed that the power of the image frequency is greatly reduced over the entire UWB frequency band of 3 to 10 GHz, so that the image frequency removal ratio is close to 99.9% or more. This confirms the broadband performance in the UWB frequency band.

When the single sideband frequency mixer circuit according to the present invention is laid out in actual production, the inverter 707 and the switch 703 are more effective in reducing the area of the circuit.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

1 is a block diagram illustrating a method of obtaining a desired output frequency through two single sideband frequency mixers and a frequency selector according to an exemplary embodiment.

FIG. 2 is a block diagram illustrating a method of controlling an output frequency of a single sideband frequency mixer through a mode controller according to another exemplary embodiment.

3 is a diagram showing frequency bands 528 MHz apart in the frequency domain of UWB, which is an application service of the present invention.

4 is a block diagram of a single sideband frequency mixer for controlling an input signal through an input path control switch as an embodiment of the present invention.

FIG. 5 is a circuit diagram illustrating the input path control switch of FIG. 4.

6 is a block diagram showing the configuration of a single sideband frequency mixer according to an embodiment of the present invention.

FIG. 7 is a circuit diagram of FIG. 6.

FIG. 8 is a block diagram showing that an RF signal is output when the frequency mixer core 704 of FIG. 7 is input as signals of different SW1 and SW2, respectively.

9 is a graph illustrating a section in which the quadrature local oscillation signals are turned on when the local oscillation signal is input, on a time axis.

10 is a graph showing that when the SW1 signal is input to the IF terminal, ω _LO + ω _IF frequencies are output.

11 is a graph showing that when the SW2 signal is input to the IF terminal, ω _{LO −} ω _IF frequencies are output.

12 is a graph illustrating an RF output signal ( ω _LO + ω _IF ) and an image frequency signal ( ω _LO - ω _IF ) when the SW1 signal is input to the IF stage and the frequency of the local oscillation signal is changed in the UWB frequency band. .

FIG. 13 is a graph illustrating an RF output signal ( ω _LO − ω _IF ) and an image frequency signal ( ω _LO + ω _IF ) when the SW2 signal is input to the IF terminal and the frequency of the local oscillation signal is changed in the UWB frequency band. .

14 is a graph illustrating an image frequency removal ratio when a SW1 signal is input to an IF terminal and a frequency of a local oscillation signal changes in a UWB frequency band.

FIG. 15 is a graph illustrating an image frequency removal ratio when a SW2 signal is input to an IF terminal and a frequency of a local oscillation signal changes in a UWB frequency band.

<Explanation of symbols for the main parts of the drawings>

301: mode controller

401,603: input path control switch

302,402: Gilbert Cell Mixer

303,403: Adder

601: IF balun

602: winning the first phase

604: Frequency Mixer Core

605: LO balun

606: second phase transition

701: IF balun circuit

702: first phase shifter circuit

703: input path control switch circuit

704: frequency mixer core circuit

705: LO balun circuit

706: second phase shifter circuit

707: inverter circuit

801: MOSFETs M1, M2, M3, and M4 Amplify IF Signals

802: MOSFET mixing IF frequency ( ω _IF ) and LO frequency ( ω _LO )

     M5, M6, M7, M8, M9, M10, M11, M12

803: RF output stage

Claims (12)

An IF (intermediate frequency) balun that outputs an input intermediate frequency signal as two intermediate frequency signals having a 180 ° phase difference; A first phase shifter for outputting the two intermediate frequency signals into four intermediate frequency signals each having a phase difference of 90 °;  LO (local oscillation) balun which outputs the local oscillation signal as two local oscillation signals having a 180 ° phase difference;  A second phase shifter for outputting the two local oscillation signals as four local oscillation signals each having a phase difference of 90 °;  An input path control switch capable of controlling an output frequency from an intermediate frequency signal input from the first phase shifter; And And a mixer core for mixing the intermediate frequency signal controlled by the input path control switch and the local oscillation signal output from the second phase shifter. The single sideband frequency mixer according to claim 1, wherein the input path control switch comprises four units and an inverter using two transistors as one unit. 3. The single sideband frequency mixer as claimed in claim 2, wherein the transistor of the input path control switch is a MOSFET. The single sideband frequency mixer according to claim 3, wherein an intermediate frequency signal is input to the source of the MOSFET and a frequency of the output signal is selectively controlled by using an inverter in a path in which a control signal is respectively input to a gate. . 3. The single sideband frequency mixer as claimed in claim 2, wherein the transistor of the input path control switch is a BJT or a similar semiconductor. The single sideband frequency mixer as claimed in claim 1, wherein the input path control switch uses a mechanical switch to control ON / OFF through mechanical contact. A first step of outputting the input intermediate frequency signal and the local oscillation signal as two signals each having a 180 ° phase difference; A second step of outputting the two intermediate frequency signals and the two local oscillation signals of the first step as four signals having a phase difference of 90 ° each;  A third step of controlling output frequencies of the four intermediate frequency signals of the second step through an input path control switch; And And a fourth step of mixing the controlled signal of the third step and the local oscillation signal of the second step. 8. The method of claim 7, wherein the input path control switch comprises four transistors and an inverter using two transistors as one unit. The method of claim 8, wherein the transistor of the input path control switch is a MOSFET. 10. The single sideband signal extraction according to claim 9, wherein an intermediate frequency signal is input to the source of the MOSFET, and an inverter is selectively used to control the frequency of the output signal by using an inverter in a path for respectively inputting a control signal to a gate. Way. 9. The method of claim 8, wherein the transistor of the input path control switch is a BJT or a similar semiconductor thereof. 8. The method of claim 7, wherein the input path control switch uses a mechanical switch to control ON / OFF through mechanical contact.

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