KR100814322B1 - Active switching mixer having improved linearity - Google Patents

Abstract

An active switching frequency mixer having an improved linearity is provided to realize the high linearity by cancelling out a third order intermodulation current component generated in a switching stage and a third order intermodulation current component generated in a transconductance stage, mutually. An active switching frequency mixer having an improved linearity comprises a transconductance stage(110) and a switching stage(120). The transconductance stage has a plurality of active elements, and at least one main signal is inputted to the transconductance stage. The switching stage is coupled with the transconductance stage, and has a plurality of active elements. At least one LO(Local Oscillator) signal is inputted to the switching stage, and at least one IF(Intermediate Frequency) signal is outputted from the switching stage. A resonance inductor(111) is connected to a common source node of at least one active element pair or more among the plurality of active elements in the switching stage.

Description

ACTIVE SWITCHING MIXER HAVING IMPROVED LINEARITY

1 is a circuit diagram illustrating a prior art monolithic active switching frequency mixer.

2 is a view for explaining the generation path of the intermodulation current in the prior art mono-balanced active switching frequency mixer.

3 shows the periodicity primary and tertiary current transfer coefficients of the switching pair as a function of the magnitude of the drive power of the switching pair.

4 illustrates the phase difference between the third-order intermodulation current and the main signal current generated by the switching stage when the parasitic capacitance Cp is present in the switching stage of the active switching frequency mixer according to the change of the inductor value Lt. The graph shows that the phase difference between the intermodulation current and the main signal current is adjusted according to the inductor value.

FIG. 5 is a circuit diagram illustrating a monolithic active switching frequency mixer with improved linearity as a first embodiment of the present invention.

FIG. 6 is a diagram for describing a process of canceling intermodulation current in a monolithic active switching frequency mixer having improved linearity, which is a first embodiment of the present invention.

7 is a circuit diagram illustrating a dual balanced active switching frequency mixer with improved linearity as a second embodiment of the present invention.

FIG. 8 is a graph showing a difference between third-order intermodulation current characteristics with and without a resonant inductor in the dual balanced active switching frequency mixer according to the second embodiment of the present invention.

FIG. 9 is another circuit diagram illustrating a dual balanced active switching frequency mixer with improved linearity as a third embodiment of the present invention. In particular, the linearity of the third-order intermodulation current in the transconductance stage is finely adjusted for higher linearity. This is a circuit diagram of the configuration of the auxiliary circuit in order to secure.

The present invention relates to an active switching frequency mixer using a FET, and more particularly, to improving the linearity of an active switching frequency mixer.

Portable wireless transmitters and receivers require frequency mixers with high linearity to prevent degradation of receiver sensitivity due to intermodulation under limited power consumption conditions. A frequency mixer is a device for obtaining the difference between an input RF signal and a signal of a local oscillator (hereinafter referred to as "LO"), which is called an intermediate frequency (IF).

In order to achieve the linearization of the frequency mixer, in order to increase the linearity of the transconductance stage for amplifying the RF signal, the source stage of the RF amplification transistor is symmetrically with the degeneration or the input voltage. It is widely known to form a current mirror, and the most widely used frequency mixer is a Gilbert cell structured frequency mixer.

1 is a circuit diagram illustrating a prior art monolithic active switching frequency mixer. The prior art monolithic active switching frequency mixer shown consists of a transconductance stage 10 and a switching stage 20.

Here, the transconductance stage 10 amplifies the main signal by converting the input RF voltage into a current in response to the main signal RFIN + which is an RF signal. The switching stage 20 is switched in response to the LO signal and outputs a first IF (IF +) and a second IF (IF−).

Here, the capacitor 4 is connected to the gate terminal of the first transistor 6 constituting the transconductance terminal 10, and the main signal RFIN + is supplied thereto. The switching stage 20 is provided with resistors and capacitors 28, 32, 34, 36 constituting the load. LO signals LO + and LO- having a predetermined phase difference 180 (are differentially applied to the second transistor 14 and the third transistor 16 provided in the switching stage 20.

The active switching frequency mixer of the related art having the above-described circuit configuration has a differential pair of second transistor 14 and third transistor when a current is generated in the transconductance stage 10 by the input main signal RFIN +. By 16, the LO signal and the main signal are mixed to generate IF signals (RF-LO or LO-RF) which are the differences. At this time, the IF signal applied to the drain of each of the first transistor 14 and the second transistor 16 has a predetermined phase difference (180 ㅀ).

In the prior art active switching frequency mixer, intermodulation components are generated in a band of an RF signal by nonlinear components (eg, capacitance between gate and source terminals) in the first transistor 6 of the transconductance stage 10. This intermodulation component eventually affects the RF main signal to generate a third order intermodulation current component in the band of the RF main signal across the output stage (drain) of the switching stage 20.

Therefore, although circuit configurations for reducing such nonlinearity have been proposed in the related art, the present inventors further consider that the intermodulation current component caused by the nonlinearity of the transconductance stage 10 achieves excellent linearity. It is observed that there is a limit to. This is because the intermodulation current component and the phase occurring in the switching stage 20 are not considered as will be described in detail below.

The present invention is to overcome the above limitation, the current component delivered to the load by canceling the third intermodulation current generated in the transconductance stage and the third intermodulation current generated in the switching stage mutually in an active switching frequency mixer It is an object to improve the linearity of the frequency mixer by having only this main signal current component.

More specifically, the present invention adjusts the phase of the intermodulation current component generated in the circuit of the switching stage consisting of two active elements, and adjusts the sign and magnitude of the intermodulation current generated in the transconductance stage so that they cancel each other out. This is to improve linearity.

In addition, in the present invention, the phase of the third-order intermodulation current generated by the nonlinearity of the switching stage in the active switching frequency mixer maintains the inverse phase relationship (permissible error range: ± 30 °) with the main signal, and in the transconductance stage. The generated third-order intermodulation current aims to implement an auxiliary circuit to maintain the relationship between the main signal and the same phase (permissible error range: ± 30 °).

The active switching frequency mixer according to the first aspect of the present invention for achieving the above object, a transconductance stage having a plurality of active elements and one or more main signals are input, coupled to the transconductance stage and a plurality of active elements An active switching frequency mixer comprising: a switching stage having one or more LO signals input thereto and one or more IF signals outputted;

And a resonant inductor coupled to a common source node of at least one active element pair of the plurality of active elements of the switching stage.

Preferably, the resonant inductor is set such that the second intermodulation current generated in the switching stage has a reverse phase relationship (general tolerance range: ± 30 °) with the main signal current.

The transconductance stage may include an auxiliary circuit for generating a first intermodulation current having the same phase as the main signal current (permissible error range: ± 30 °) and outputting the first intermodulation current to the switching stage.

Furthermore, the transconductance stage includes an auxiliary circuit for generating a first intermodulation current having an in phase with the main signal current (permissible error range: ± 30 °) and outputting it to the switching stage. The second intermodulation current generated in the switching stage is set to have a reverse phase relationship (permissible error range: ± 30 °) with the main signal current, such that the first intermodulation current and the second intermodulation current cancel each other. It may be as possible.

According to a specific application, the active switching frequency mixer may be a single balanced mixer, and the transconductance stage may share a first intermodulation current in phase (tolerance range: ± 30 °) with the main signal current. And a first active element and a first 'active element for generating and outputting the switching stages, wherein independent bias voltages and main signal voltages are applied to gates of the first active element and the first' active element, respectively. Can be.

In addition, a bias voltage applied to the gates of the first active element and the first 'active element, respectively, may operate the first active element in a strong inversion region and operate the first' active element in a threshold voltage region. It may be set.

The switching stage may include a second active element and a third active element forming a common source terminal, and the resonant inductor may have one end connected to the common source terminal and the other connected to ground. have.

On the other hand, for other applications, the active switching frequency mixer may be a double balanced mixer, wherein the switching stage comprises: a third active element and a fourth active element, a second active element forming a first common source terminal; And a fifth active element and a sixth active element forming a common source terminal, wherein the resonant inductor may be coupled between the first common source terminal and the second common source terminal.

The transconductance stage may include a first active element and a first 'active element connected to the first common source terminal, a second active element and a second' active element connected to the second common source terminal, A bias voltage for operating the first active element and the second active element in the strong inversion region is input to the gates of the first active element and the second active element, and the first 'active element and the second active element are input. A bias voltage for operating the first active element and the second active element in a threshold voltage region may be input to a gate of an active element.

In another example, the transconductance stage may include a first active element and a second 'active element connected to the first common source terminal, a first' active element and a second active element connected to the second common source terminal. And a bias voltage for operating the first active element and the second active element in a strong inversion region, a first main signal, and a second main signal at gates of the first active element and the second active element. Respectively applied to the gates of the first active element and the second active element; a bias voltage and the first active element for operating the first active element and the second active element in a threshold voltage region; And an output voltage of the second active element may be applied respectively.

According to a second aspect of the present invention, an active switching frequency mixer is an active switching frequency mixer including a transconductance stage and a switching stage, and is provided in the transconductance stage, and has a main signal current and a phase (permissible error range: ± Circuit means for generating a first intermodulation current of 30 [deg.]); And circuit means provided in the switching stage, and configured to adjust the second intermodulation current generated in the switching stage to cancel the first intermodulation current.

Wherein the circuit means for adjusting to cancel the first intermodulation current comprises circuit means for causing the second intermodulation current to have a relationship between the main signal current and an inverse phase (permissible error range: ± 30 °). Can be.

Here, the circuit means for adjusting in the reverse phase relationship may be a resonant inductor connected to the common source terminal of the active element pair included in the switching stage.

In addition, the first intermodulation current generation circuit means may include a first active element for generating a first intermodulation current having the same phase as a main signal current and an allowable error range of ± 30 ° and outputting the first intermodulation current to the switching stage; And a first 'active element, wherein the first active element operates in a strong inversion region and the first' active element operates in a threshold voltage region. It may further comprise a circuit means.

According to a third aspect of the present invention, an active switching frequency mixer includes a transconductance stage having a plurality of active elements and to which one or more main signals are input, and a plurality of active elements coupled to the transconductance stage and having at least one LO signal. And a switching stage to which one or more IF signals are output, wherein the transconductance stage generates a first intermodulation current having an in phase (tolerance range: ± 30 °) with the main signal current. It characterized in that it comprises an auxiliary circuit for outputting.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. The accompanying drawings and the following embodiments are merely intended to describe examples of specific circuit configurations for easy understanding by those skilled in the art, and are not intended to limit the scope of the technical idea of the present invention.

As shown in FIG. 2, the intermodulation component may be generated not only by the transconductance stage 10 but also by the switching stage 20, and finally, the two components are delivered to the load together. The third intermodulation current generated in the transconductance stage 10 (the current at the bottom of FIG. 2, B) is generated by the third order nonlinear voltage-current characteristic of the first transistor 6, and the first transistor 6 The intermodulation current has a negative sign as shown because it operates mainly in the strong inversion region. Thus, the third intermodulation current has a reverse phase with respect to the main signal current.

The third intermodulation current generated in the switching stage 20 (the current at the bottom of FIG. 2, C) has a reverse phase relationship with the main signal current at low frequencies, but as the frequency increases, the source node of the transistors 14 and 16 of the switching stage is increased. The parasitic capacitance at deviates the phase from the relationship between the main signal current and the reverse phase and increases its magnitude.

Therefore, in the switching stage 20, there is a problem that the intermodulation current generated in the transconductance stage 10 and transmitted (middle of FIGS. 2 and C) and the intermodulation current generated in the switching stage 20 do not cancel each other. .

3 shows the value of the periodic third order nonlinear coefficients occurring in the switching pair as a function of the magnitude of the driving power of the switching pair. To obtain the result of FIG. 3, the inventor analyzed the active switching frequency mixer as follows.

Assuming no parasitic capacitance in the active switching frequency mixer, the intermodulation current delivered to the final load is the third intermodulation current term generated by the third order nonlinearity of the transconductance stage 10 and the switching stage 20. It is given by the sum of intermodulation current terms generated by the periodic third order nonlinearity of. Therefore, the amount of intermodulation distortion can be approximated by the following equation.

는 각각 트랜스컨덕턴스 단의 선형 이득(트랜스컨덕턴스:

)과

의 2계 도함수인 3차 비선형 특성

에 해당한다.

는 각각 스위칭 단 내의 능동 소자 쌍의 1차 선형 전류 전달 특성과 3차 비선형 전류 전달 특성이다. 이때 트랜스컨덕턴스 단에 보조 소자를 이용하여

의 값을 0으로 만드는 방법을 사용하더라도 전체 혼변조 전류를 어느 정도 줄일 수는 있을 것이나, 후단의 스위칭 쌍에서 발생하는 비선형 왜곡이 상존하기 때문에 주파수 혼합기의 선형성을 개선하는데 한계가 있다.From the stomach

Are the linear gains of the transconductance stage, respectively.

)and

Third-order Nonlinear Characteristics of Second-order Derivatives of

Corresponds to

Are the primary linear current transfer characteristics and the tertiary nonlinear current transfer characteristics of the active element pair in the switching stage, respectively. In this case, by using an auxiliary element in the transconductance stage

Even if the value of is set to 0, the overall intermodulation current can be reduced to some extent, but there is a limit to improving the linearity of the frequency mixer because nonlinear distortions occurring in the later switching pairs exist.

의 부호 및 크기가 변화함이 알려져 있는데, 도 3의 결과를 보면 통상의 구동 파라미터 영역에서

(45)의 부호는 음(-)이 됨을 확인할 수 있다. 그러므로 능동 스위칭 주파수 혼합기의 일반적인 설계에서, 능동소자의 기 생 커패시턴스를 무시할 경우, 스위칭 쌍에 의해 발생하는 3차 혼변조 전류성분은 음이 되어, 원래의 기본 주파수 전류성분과 역위상의 관계를 갖게 된다.Generally, the bias current applied to the MOS switching pair and the voltage magnitude of the switching pair driving signal

It is known that the sign and the size of are changed. Referring to the result of FIG.

It can be seen that the sign of (45) becomes negative (-). Therefore, in the general design of an active switching frequency mixer, when neglecting the parasitic capacitance of an active element, the third-order intermodulation current generated by the switching pair becomes negative, which has an inverse relationship with the original fundamental frequency current component. do.

Therefore, when the parasitic capacitance is ignored, it is possible to cancel the third-order intermodulation current component generated in the switching pair having such negative tertiary nonlinearity by the third-order intermodulation current component generated in the transconductance stage, and the load By setting the third-order intermodulation distortion current component to be zero, only the linear current component can be delivered to the final load.

의 값을 변화시킬 수 있는데, 특히 통상의 구동 영역에서는

는 음의 값을 갖는다. 또한,

은 양의 값을 갖기 때문에

의 크기를 조절하고,

가 양의 값을 갖도록 조절하면 위의 수학식에서 IM3의 값을 상쇄시킬 수 있는 것이다.

과

의 비는 소자의 크기가 결정되면 고정되기 때문에, 위 수학식 1의 값을 0으로 만들기 위해서는

의 값을 일정하게 한 상태에서

의 값을 독립적으로 부호와 크기를 조절하는 방법이 필요하다.In other words, basically adjusting the bias current of the switching pair and the output of the local oscillator

Can be changed, especially in the normal driving range.

Has a negative value. Also,

Has a positive value

To resize,

Is adjusted to have a positive value, it is possible to cancel the value of IM3 in the above equation.

and

Since the ratio of is fixed when the size of the device is determined, to make the value of Equation 1 above 0

With the value of constant

We need a way to control the sign and scale independently of the value of.

In addition, since the parasitic capacitance component is not zero in an actual MOS device, a phase difference occurs in the intermodulation current, and accordingly, a method to solve this problem is required to further improve the linearization performance. There is a further need for a method capable of maintaining the phase of the intermodulation current generated in the switching stage in the reverse phase even in the region.

FIG. 4 illustrates the phase difference between the intermodulation current and the main signal current when the parasitic capacitance Cp of the common source node of the switching pair is present, and when the inductor is connected to ground, for a change in inductance value. The infinitely large inductance is the same as the absence of the inductor, so it can be seen that the intermodulation current component no longer maintains a 180 degree phase relationship with the main signal current component without the inductor.

Accordingly, in addition to the above-described nonlinear coefficient adjustment of the transconductance stage and the switching stage, the degree of linearization of the active switching frequency mixer can be increased.

By observing the characteristics of the active switching frequency mixer as described above, the present inventor proposes the circuit configuration of the following embodiment.

FIG. 5 is a circuit diagram illustrating a monolithic active switching frequency mixer with improved linearity as a first embodiment of the present invention.

In contrast to the prior art monolithic active switching frequency mixer of FIG. 1, the difference is described. In the circuit configuration of the embodiment, the first 'transistor 105 is connected in parallel to the transconductance stage 110, and the original signal RFIN ) Is commonly input to the gates of the first transistor 6 and the first 'transistor 105. The bias of the first transistor 6 and the first 'transistor 105 is independently adjusted, and bias supplies 107 and 108 are provided for this purpose.

In the bias supply units 107 and 108, the first transistor 6 operates in the strong inversion region, and the first 'transistor 105 supplies a bias voltage for controlling to operate in the region near the threshold voltage. Here, the circuit arrangements 103, 105, and 108 added in comparison with the prior art of FIG. 1 constitute an 'auxiliary circuit' so that the intermodulation current of the transconductance stage 110 has a positive sign.

In addition, a resonant inductor 111 is added to the common source terminal of the second transistor 14 and the second transistor 16 in the switching stage 120 of the present embodiment. One end of the resonant inductor 111 is connected to an AC ground node. As described above, the resonant inductor 111 compensates for the phase difference of the intermodulation current generated in the switching stage 120 in consideration of the parasitic capacitance of the switching stage 120.

FIG. 6 is a diagram for describing a process of canceling intermodulation current in a linear active switching frequency mixer having improved linearity, which is a first embodiment of the present invention.

The input original signal A 'passes through the first transistor 6 and the first' transistor 105 of the transconductance stage 110, and the output current has positive intermodulation components and negative intermodulation components, respectively. (B ', C'). In this case, as shown in FIG. 6, when the positive intermodulation component prevails, the positive output of the transconductance stage 110 together with the main signal current component, and the positive intermodulation current component of the same phase appear. (D ').

These current components pass through the switching stage 120, the LO frequency is mixed, the intermodulation current component generated in the switching stage 120 is phase-corrected by the inductor to have a phase difference of 180 degrees with the main signal current component, Since the phase difference of the intermodulation current generated and transmitted from the transconductance stage 110 has a 180 degree, the two can be accurately canceled (F ').

This is possible because the active element constituting the circuit has a positive third order nonlinearity in the weak inversion region. Through this, the total third-order intermodulation current components generated in the transconductance stage 110 may be adjusted to have a positive sign.

As described above, when an inductor is attached to the switching stage 120, and an auxiliary circuit (FET, etc.) is added to the transconductance stage 110, the phase of the tertiary intermodulation current generated in the switching stage is inverse to that of the main signal current. As a result, the third intermodulation current generated in the transconductance stage can be adjusted in phase with the main signal current. In addition, by adjusting the size of the FET in the auxiliary circuit and the like so that the sizes of the two intermodulation components having the reverse phase relationship are the same, the third intermodulation current component is finally reduced from the current component delivered to the load of the frequency mixer. This can be achieved by achieving high linearity characteristics of the frequency mixer.

The technical idea of the present invention can be modified and applied according to various applications. 7 is a circuit diagram illustrating a dual balanced active switching frequency mixer with improved linearity as a second embodiment of the present invention.

In the dual balanced active switching frequency mixer of the embodiment, the main signals RFIN + and RFIN-, which are differentially input to the transconductance stage 210, are respectively passed through the capacitors 203, 204, 213, and 214, and thus the first transistor 206, It is input to the gate terminals of the first 'transistor 205, the second transistor 216, and the second' transistor 215.

The first transistor 206 and the second transistor 216 are biased by the bias supplies 207 and 218 so as to operate in the strong inversion region, respectively, and the first 'transistor 205 and the second' transistor 215 are applied. The bias is applied by the bias supplies 208 and 217 to operate in the region near the threshold voltage, respectively.

The basic operation principle of the auxiliary circuit provided in the transconductance stage 210 is the same as that of the first embodiment described above, and is intended to make the intermodulation signal output from the transconductance stage 210 have a positive sign.

On the other hand, unlike the first embodiment, the resonant inductor 221 has the common source terminal of the third transistor 226 and the fourth transistor 228, and the common of the fifth transistor 232 and the sixth transistor 234. It is connected between the source terminals. Also in this case, the resonant inductor 221 is for correcting the phase difference of the intermodulation current component due to the parasitic capacitance of the switching stage 220. As a result, the resonant inductor 221 and the intermodulation current component output from the transconductance stage 210 are used. The intermodulation component output from the switching stage 220 may be canceled out.

The operation of the other circuits is not significantly different from the operation of a general double balanced active switching frequency mixer, and thus the detailed description is omitted.

FIG. 8 is a graph showing a difference between third-order intermodulation current characteristics with and without a resonant inductor in the dual balanced active switching frequency mixer according to the second embodiment of the present invention. As shown, when the resonant inductor 221 is added or not, the output of the main signal does not show a big difference (a: the main signal output when the resonant inductor is added, and b: the resonant inductor is It is observed that the output of the intermodulation current component shows no significant difference (c: the output of the intermodulation component when a resonant inductor is added, and d: the intermodulation component without a resonant inductor). Output). In this way, by adding the resonant inductor, the intermodulation current component generated in the transconductance stage and the intermodulation current component generated in the switching stage are canceled to obtain higher linearity.

FIG. 9 is a third embodiment of the present invention. Even when the intermodulation current is in phase with the main signal current using the auxiliary transistor as described above, the intermodulation current and the main signal current generated in the transconductance stage are generally high frequency. Although the in-phase relationship is maintained, a phenomenon arises that the in-phase relationship is somewhat deviated by the feedback of the capacitance of the active element.

Ultimately, the final purpose is to maintain the reverse phase relationship between the intermodulation current generated in the transconductance stage and the intermodulation current generated in the switching stage. For this purpose, the phase of the intermodulation current of the transconductance stage is finely adjusted. Means can be taken to more accurately reverse the phase with the intermodulation currents that occur.

For this purpose, as shown in FIG. 9, an inductor Lg may be added to the gate input terminal, and a second inductor Ls may be added and used as necessary. Inductances of the inductors attached to the common source terminal of the input terminal and the transformer terminal may be used to maintain the small value but to adjust the value appropriately so as to finely adjust the phase difference (see, for example, FIG. 4).

In FIG. 9, except for the inductor Lg and the second inductor Ls, the remaining circuit configuration is not different from the circuit configuration of the second embodiment of FIG. 7, and thus detailed descriptions of other parts will be omitted.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described specific embodiments, and the present invention is not usually limited to the scope of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

According to the present invention, the linearity generated in the frequency mixer by canceling the intermodulation current component by adjusting the third order nonlinearity of the transconductance stage to a positive value in the active switching frequency mixer, and negatively adjusting the nonlinearity of the switching stage. The effect of improving can be obtained.

In addition, the present invention minimizes the phase shift of the intermodulation current generated by the parasitic capacitance by using an inductor at the common source node of the switching stage, so that the phase of the intermodulation current generated in the switching stage is high even at a high frequency. The effect is to maintain the reverse phase with. In particular, it was found that the linearity of the frequency mixer can be improved by more than 10dB.

Claims (16)

A transconductance stage having a plurality of active elements and having at least one main signal input thereto, and a switching stage coupled to the transconductance stage, having a plurality of active elements, having at least one LO signal input and at least one IF signal being outputted; Active switching frequency mixer, And a resonant inductor coupled to a common source node of at least one pair of active elements of said plurality of active elements of said switching stage. The method of claim 1, The resonant inductor, And the second intermodulation current generated in the switching stage is set to have a reverse phase relationship with the main signal current. The method of claim 1, The transconductance stage, And an auxiliary circuit for generating a first intermodulation current in phase with said main signal current and outputting it to said switching stage. The method of claim 1, The transconductance stage, An auxiliary circuit for generating a first intermodulation current co-phase with the main signal current and outputting the same to the switching stage; The resonant inductor, The second intermodulation current generated in the switching stage is set to have a reverse phase relationship with the main signal current, And the first intermodulation current and the second intermodulation current cancel each other. The method of claim 1, The active switching frequency mixer is a single balanced mixer, The transconductance stage includes a first active element and a first 'active element for generating a first intermodulation current in phase with the main signal current and outputting the same to the switching stage. An active switching frequency mixer, characterized in that the independent bias voltage and the main signal voltage is applied to the gate of the 1 'active element. The method of claim 5, A bias voltage applied to the gates of the first active element and the first 'active element, respectively, is set to operate the first active element in a strong inversion region and to operate the first' active element in a threshold voltage region. Active switching frequency mixer. The method of claim 5, The switching stage includes a second active element and a third active element forming a common source terminal, And wherein the resonant inductor has one end connected to the common source terminal and the other end connected to ground. The method of claim 1, The active switching frequency mixer is a double balanced mixer, The switching stage includes a third active element and a fourth active element forming a first common source terminal, a fifth active element and a sixth active element forming a second common source terminal, The resonant inductor is coupled between the first common source terminal and the second common source terminal. The method of claim 8, The transconductance stage includes a first active element and a first 'active element connected to the first common source terminal, a second active element and a second' active element connected to the second common source terminal, A bias voltage for operating the first active element and the second active element in the strong inversion region is input to the gates of the first active element and the second active element, An active switching frequency input to a gate of the first active element and the second active element, a bias voltage for operating the first active element and the second active element in a threshold voltage region; Mixer. The method of claim 8, The transconductance stage includes a first active element and a second 'active element connected to the first common source terminal, a first' active element and a second active element connected to the second common source terminal, To the gates of the first active element and the second active element, a bias voltage, a first main signal and a second main signal for operating the first active element and the second active element in the strong inversion region are applied, respectively. , A gate of the first active element and the second active element may include a bias voltage for operating the first active element and the second active element in a threshold voltage region, and the first active element and the second active element. Active switching frequency mixer, characterized in that the output voltage of the device is applied respectively. In an active switching frequency mixer comprising a transconductance stage and a switching stage, Circuit means provided at the transconductance stage, the circuit means for generating a first intermodulation current in phase with a main signal current; And And circuit means provided in said switching stage, said circuit means for adjusting a second intermodulation current generated in said switching stage to cancel said first intermodulation current. The method of claim 11, And circuit means for adjusting the first intermodulation current to cancel, comprising circuit means for causing the second intermodulation current to have a reverse phase relationship with the main signal current. The method of claim 12, And circuit means for adjusting in relation to the reverse phase is a resonant inductor connected to a common source terminal of an active element pair included in the switching stage. The method of claim 11, The circuit means for generating a first intermodulation current includes a first active element and a first 'active element for generating a first intermodulation current in phase with a main signal current and outputting the same to the switching stage. Active switching frequency mixer. The method of claim 14, Active circuitry further comprising circuit means for applying a bias to each gate such that the first active element operates in a strong inversion region and the first 'active element operates in a threshold voltage region. . A transconductance stage having a plurality of active elements and having at least one main signal input thereto, and a switching stage coupled to the transconductance stage, having a plurality of active elements, having at least one LO signal input and at least one IF signal being outputted; Active switching frequency mixer, The transconductance stage, And an auxiliary circuit for generating a first intermodulation current in phase with said main signal current and outputting it to said switching stage.

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