JP2003198329A - Active poly-phase filter amplifier, mixer circuit, and image rejection mixer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image rejection mixer with excellent performance being more stable compared with that of the conventional one, to provide an active poly-phase filter amplifier which is used for a circuit such as the image rejection mixer to improve the performance of the circuit, and also to provide mixer circuits. <P>SOLUTION: The first and the second mixer circuits 13 and 14 are constituted of a Gilbert mixer with base-grounded differential amplifier inserted therein. Then a distortion characteristic is improved and OIP 3 is enhanced. First and second kinds of phase equipment 11 and 12 are constituted by using different types of poly-phase filters. When nonuniformity occurs in a constant number, a deviation in a phase rotation angle in each poly-phase filter is generated in a reverse direction. Thus, an excellent image rejection characteristic is kept concerning nonuniformity in the constant number of circuit elements. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an RF (Radio Freq
uency: a wireless communication system using the radio frequency band,
For example, the present invention relates to an active polyphase filter amplifier and mixer circuit suitable for use in a receiving circuit portion or a transmitting circuit portion in a wireless communication system based on the Bluetooth standard, and an image rejection mixer.

[0002]

2. Description of the Related Art In a receiver in a wireless communication system,
A received signal (desired received signal) in a desired frequency band (for example, RF band) is transmitted locally as a local signal (local (LO) signal) S
_{A process} of mixing with _LO and performing frequency conversion to an IF (Intermediate Frequency) signal S _IF is performed. On the contrary, in the transmitter, the IF signal S _IF is mixed with the local signal S _LO and converted into a transmission signal (desired transmission signal) in a desired frequency band (for example, RF band). A circuit that mixes two or more input signals and obtains a frequency-converted output signal is called a mixer circuit. In recent years, the configuration of the entire receiving or transmitting circuit including a mixer circuit has been
With the development of grated circuit (integrated circuit) technology, development is proceeding in the direction of high integration and one chip.

In the mixer circuit of the receiving system, the local signal S
_{When the LO} frequency is f _LO, no matter whether the frequency is higher than the intermediate frequency f _IF (f _LO + f _IF ) or low (f _LO −f _IF ), it responds to the input signal. , To the intermediate frequency f _IF .

Therefore, as shown in FIG.
For example, the local oscillation frequency f_LOFrequencies in the upper sideband with respect to
Number f_RF(= F_LO+ F_IF) RF signal S which is desired signal
_RFFrequency f in the lower sideband when received as
_IM(= F_LO-F_IF) Other signal S_IMIs entered, the
The mixer circuit sets the desired RF signal S_RFNot only other
Signal S_IMResponding to the IF signal S_IFWill be converted to.
That is, the IF signal S _IFThe signal component you want to convert to
Number f_RFRF signal S_RFFrequency f_IMOther
Signal S_IMFunction as an interfering wave and cause reception failure.
Let This interference wave has a frequency f_IMIs the local oscillation frequency
f_LODesired reception frequency f_RFAnd just a mirror image
Because of the positional relationship, it is called “Image signal”.
It is exposed. Also, the image signal S_IMFrequency f_IMIs
Image signal S, which is called "image frequency"_IMby
The reception failure is called "image jamming".

This image signal _SIM is also generated in the mixer circuit of the transmission system. That is, as shown in FIG. 16 (B), when mixing the local signal S _LO frequency f _IF of the IF signal S _IF frequency f _LO, for sending signals to desired only RF signal S _RF Another signal is also generated in the sideband opposite to the RF signal S _RF with respect to the local oscillation frequency f _LO . The signal generated in the opposite sideband is the image signal _SIM . In the circuit of the transmission system, this image signal S
_IM needs to be removed before the final antenna output.

In order to remove this image signal _SIM ,
Conventionally, a signal removal method using an external BPF (bandpass filter) circuit, particularly a filter circuit called a SAW (Surface Acoustic Waves) filter, is generally adopted.

FIG. 13 shows a configuration example of a transmission circuit using an external filter circuit. In this circuit example, built-in low-pass filters (LPF) 301 and 302, modulator 3
03, a local oscillator (OSC) 304, and a mixer circuit 304 are provided in one IC chip 300. Image rejection filter 310 for removing an image signal S _IM is external to the IC chip 300. A power amplifier (PA) 320 is provided on the output side of the image removal filter 310.

In this circuit, the I-channel baseband (BB) signal S _I is balanced-input to the built-in LPF 301. In addition, the Q channel baseband signal S _Q has a built-in L
Balanced input to the PF 302. Built-in LPF 301, 30
2 outputs a predetermined frequency component of the input signals S _I and S _Q to the modulator 303. The modulator 303 has a built-in LPF
Modulates the signal input via 301 and 302, and
Balanced output of signal S _IF . The mixer circuit 304 mixes the IF signal S _IF from the modulator 303 and the local signal S _LO from the local oscillator 304, and outputs the RF signal S _RF converted into the frequency f _RF in a balanced manner. At this time, the mixer circuit 304 also outputs the image signal _SIM . Image rejection filter 310 of the signal from the mixer circuit 304, to remove an image signal S _IM, and passes only the RF signal S _RF. The power amplifier 320 amplifies and outputs the RF signal S _RF from the image removal filter 310.

By using the external filter circuit as described above, the image signal _SIM can be removed. However, the use of an external filter circuit has problems that the number of circuit elements increases, the size of the entire circuit increases, and the cost increases. Therefore, in recent years, a mixer circuit called an “image rejection mixer” that does not require an external filter has been developed. The image rejection mixer is a standalone image signal _SIM.
Is configured to be removable. By using this image rejection mixer, for example, in the case of a circuit of the transmission system, it becomes possible to remove the image signal _SIM at a stage before the external filter circuit. As a result, as compared with the case where an external filter circuit is used, the configuration is superior in terms of the number of circuit elements, system cost, circuit distortion, and the like.

The image rejection mixer is shown in FIG.
, The first and second 90 ° phaser 41
1, 412 and the first and second mixer circuits 413, 4
14 and an adder 415. First
The second mixer circuits 413 and 414 are generally composed of Gilbert mixers. First and second 90 °
RC filters are generally used for the phase shifters 411 and 412. The overall configuration of the transmission circuit using the image rejection mixer 401 is similar to that of the mixer circuit 304 in the circuit of FIG.
And the image removal filter 310 is omitted from the circuit configuration.

In the image rejection mixer 401 shown in FIG. 14, the first 90 ° phase shifter 411 has a
The IF signal S _IF from the modulator 303 is input. At this time, signal input to the first 90 ° phase shifter 411 is performed in a balanced manner. That is, a pair of balance signals having 180 ° different phases are input as the IF signal S _IF . First 90 °
The phase shifter 411 divides the input IF signal S _IF into two types of balanced signals that are phase-shifted by 90 ° and outputs the two types of balanced signals. One of the divided IF signals S _IF (phase 0 °,
180 °) is input to the first mixer circuit 413.
The other (phase 90 °, 270 °) is connected to the second mixer circuit 4
14 is input.

On the other hand, the local signal S _LO from the local oscillator 304 is input to the second 90 ° phase shifter 412.
At this time, the signal input to the second 90 ° phase shifter 412 is performed in a balanced manner. That is, a pair of balance signals having 180 ° different phases are input as the local signal S _LO . The second 90 ° phaser 412 receives the input local signal S
_{The LO} is split into two types of balanced signals with a 90 ° phase shift and output. One of the divided local signals S _LO (phase 0 °, 180 °) is supplied to the second mixer circuit 41.
4 is input. The other (phase 90 °, 270 °) is input to the first mixer circuit 413.

The first mixer circuit 413 has a first 90 °
The IF signal S _IF input through the phase shifter 411 and the second signal
The local signal S _LO input through the 90 ° phase shifter 412 is mixed to generate two kinds of signals (having different frequencies) in the upper sideband and the lower sideband with respect to the local oscillation frequency f _LO . To do. Similarly, the second mixer circuit 414 also mixes the IF signal S _IF and the local signal S _LO to generate the local oscillation frequency f.
_It produces two types of signals in the upper and lower sidebands for _LO . First and second mixer circuits 413, 414
The two types of signals generated in 1 are output to the adder 415.
At this time, if the phase relationship between the two types of signals output from the first mixer circuit 413 and the two types of signals output from the second mixer circuit 414 is appropriately adjusted, the upper and lower sidebands Only the desired signal component can be output from the adder 415 as the desired RF signal S _RF .
That is, the desired signal component is passed through the adder 415 in phase agreement. On the other hand, other undesired signal components, that is, the image signal S _IM , are canceled and eliminated by reversing the phase relationship.

[0014]

However, as shown in FIG.
When the function of the image rejection mixer 401 shown in FIG. 2 is configured by the conventional circuit technology, the image signal removal characteristic called image rejection characteristic is weak against the variation in the constants of the circuit elements generated in the IC manufacturing process. There is a problem. As an example, when the image rejection mixer 401 is configured by a commonly used circuit called RC-RC configuration, the resistance value of the resistance element R and the capacitance value of the capacitor C are in the same direction with respect to the design value. When 20% variation occurs, the image rejection of Typ.> 40 dB is reduced to around 20 dB.

The RC-RC configuration means two 90 ° phase shifters 4 in the image rejection mixer 401.
The reference numerals 11 and 412 are composed of an RC low-pass filter and an RC high-pass filter. In order to properly remove the image signal by the image rejection mixer 401, the final stage of the circuit (adder 41
Regarding the image signals from the mixer circuits 413 and 414 input to 5), it is necessary that the amplitude and the phase satisfy predetermined conditions. That is, if the respective image signals have a relationship in which the amplitudes are equal and the phases are inverted, the image signals cancel each other and can be satisfactorily removed. In the circuit having the RC-RC configuration, the relationship of the amplitude tends to be broken from the ideal state with respect to the variation of the constants of the circuit elements, and there is a problem that the image rejection characteristic is deteriorated.

Therefore, each 90 ° phaser 411, 412
May be configured with another filter, for example, a poly-phase filter, instead of the RC filter. It is considered that the polyphase filter generally has less deterioration of the image signal removal characteristic with respect to the variation of the constant, as compared with the RC-RC configuration. The applicant of the present application also applied for a patent 20
No. 01-85065 proposes a novel circuit for the image rejection mixer of the receiving system, in which the image rejection characteristic is improved by using a polyphase filter.

FIG. 15 shows an example of the configuration of a conventional image rejection mixer of a transmission system using a polyphase filter. Note that, in FIG. 15, portions corresponding to the respective circuit blocks shown in FIG. 14 are designated by the same reference numerals.

In this circuit example, resistors R79 and R80 are used.
Constitute an adder 415. Resistor R77 and transistors Q63 and Q64, and transistor Q7
1 to Q74 form a first mixer circuit 413. The resistor R78, the transistors Q65 and Q66, and the transistors Q75 to Q78 form a second mixer circuit 414.

In this circuit example, each of the first and second mixer circuits 413 and 414 has a Gilbert mixer configuration. That is, the first mixer circuit 413
, The resistor R77 and the transistors Q63, Q
Reference numeral 64 forms a grounded differential amplifier section of the Gilbert mixer, and transistors Q71 to Q74 form a mixer cell of the Gilbert mixer. Constant current sources I61 and I62 are connected to the differential amplifier section.

In the second mixer circuit 414, the resistor R78 and the transistors Q65 and Q66 are
Forming a grounded-emitter differential amplifier in the Gilbert mixer, the transistors Q75 to Q78 are Gilbert
It forms the mixer cell in the mixer. Constant current sources I63 and I64 are connected to the differential amplifier section.

In this circuit example, the first and second 90 °
Each of the phase shifters 411 and 412 is formed of the same type of two-stage polyphase filter. That is, for the first 90 ° phaser 411, the resistance R5
1 composed of 1 to R54 and capacitors C51 to C54
A two-stage polyphase filter is formed by the second-stage polyphase filter including the resistors R55 to R58 and the capacitors C55 to C58. In addition, the second 90 ° phase shifter 41
For 2, the resistors R41 to R44 and the capacitor C
41-C44 first-stage polyphase filter, resistors R45-R48 and capacitors C45-C4
2 with the second stage polyphase filter consisting of 8
A polyphase filter having a step structure is formed.

At the input stage of the first 90 ° phaser 411,
A preamplifier 511 is connected via capacitors C73 and C74. The preamplifier 511 is a transistor Q
51 to Q54 and resistors R60 and R61. The transistors Q51 and Q52 have a constant current source I71.
Are connected.

At the input stage of the second 90 ° phaser 412,
Buffer amplifier 51 via capacitors C71 and C72
2 is connected. The buffer amplifier 512 includes transistors Q57 to Q60 and resistors R73 and R74. A constant current source I72 is connected to the transistors Q57 and Q58.

As described above, the first and second 90 ° phase shifters 41 are used as the conventional image rejection mixer.
1, 412 include those using the same type of polyphase filter. As a result, in general, good image rejection characteristics can be maintained as compared with the RC-RC configuration.

However, the image rejection mixer using this polyphase filter is still underdeveloped, and there is room for improvement. For example, using a polyphase filter, the first and second 90
The signal loss in the phase shifters 411 and 412 is large, and a separate amplifier is required to compensate for this loss, which causes a problem of increased power consumption. Also, RC-R
As a problem common to the C configuration, since the phase shifter is used especially at the input stage of the IF signal, the NF (No
ise Figure) Characteristics tend to deteriorate. To cope with this, an NF characteristic can be maintained by using an amplifier in the IF input section, but in this case, the current of the entire circuit tends to increase.

Further, by using the polyphase filter, generally, a better image rejection characteristic can be maintained as compared with the RC-RC configuration. However, in the configuration in which the same type of polyphase filter is used, a circuit is simply used. It is considered that the image rejection characteristic may be deteriorated depending on the condition of the variation of the element constant.

The first and second 90 ° phase shifters 41
A method of configuring 1, 412 with an RC filter and a polyphase filter is also conceivable. That is, a method of configuring either one of the first and second 90 ° phase shifters 411 and 412 with a polyphase filter and the other with an RC filter is also conceivable. However, even in this case,
There is a problem that the image rejection characteristic is weak against the variation in the constant of the circuit element.

In addition, although the problem regarding the phase shifter has been mentioned above, there is room for further improvement in other circuit parts (particularly, the mixer circuit) in order to improve the characteristics of the image rejection mixer. Conceivable.

The present invention has been made in view of the above problems, and the first object thereof is that the performance is stable as compared with the conventional one.
Another object is to provide an image rejection mixer with excellent performance. A second object of the present invention is to provide an active polyphase filter amplifier and mixer circuit which can be used in a circuit such as an image rejection mixer to improve the performance of the circuit. .

[0030]

An active polyphase filter / amplifier according to the present invention comprises a polyphase filter having a two-stage structure and a differential amplifier provided at a signal input stage and integrated with the polyphase filter. It is equipped with.

In the active polyphase filter / amplifier according to the present invention, the deterioration of the NF characteristic due to the polyphase filter is prevented as compared with the case where the polyphase filter is constituted alone, without additionally adding an amplifier of another constitution. The power consumption is reduced. As a result, for example, it can be used in a phase shifter part of an image rejection mixer or a phase shifter part of a QPSK quadrature modulator, and their performance is expected to be improved.

Here, the active polyphase filter / amplifier according to the present invention is further inserted between the circuit part of the first stage and the circuit part of the second stage of the polyphase filter, and integrated with the polyphase filter. A grounded base amplifier may be provided. This is expected to further improve the NF characteristics. Further, the signal loss is prevented from being reduced by the polyphase filter, and the distortion characteristic is improved.

The mixer circuit according to the present invention comprises a mixer cell forming a Gilbert mixer together with a grounded differential amplifier, and a base grounded differential amplifier inserted between the grounded emitter differential amplifier and the mixer cell. It is equipped with an amplifier.

In the mixer circuit according to the present invention, the grounded differential amplifier is inserted, so that the distortion component in the grounded emitter differential amplifier is reduced and the gain is reduced as compared with a normal Gilbert mixer. Secured.
As a result, improvement in OIP3 is expected when used in a transmission system image rejection mixer, for example.

The image rejection mixer according to the first aspect of the present invention has a first polyphase filter having a two-stage structure and divides an input signal into first and second input signals having mutually different phases. A first phase shifter for outputting
A second phase shifter which has a second polyphase filter having a two-stage configuration, and which divides the input local oscillation signal into first and second local oscillation signals having mutually different phases, and outputs the divided signals.
First mixing of a first local oscillator signal and a first input signal
And a second mixer circuit for mixing the second local oscillation signal and the second input signal, and the respective output signals from the first and second mixer circuits are added to obtain a desired frequency. And an adder for outputting a signal. Further, the connection state of each circuit element forming the first-stage circuit of the first polyphase filter and the connection state of each circuit element forming the first-stage circuit of the second polyphase filter are The connection state of each circuit element forming the second-stage circuit of the first polyphase filter and the connection state of each circuit element forming the second-stage circuit of the second polyphase filter which are in a mirror image relationship with each other. The state and the state are mirror images of each other.

An image rejection mixer according to a second aspect of the present invention is provided with a first phase shifter which divides an input signal into first and second input signals having mutually different phases and outputs the first phase shifter. A second output that divides the local oscillation signal into first and second local oscillation signals that are out of phase with each other
Phaser, a first mixer circuit for mixing the first local oscillator signal and the first input signal, and a second mixer circuit for mixing the second local oscillator signal and the second input signal. , An adder that adds the respective output signals from the first and second mixer circuits and outputs a signal of a desired frequency. Further, each of the first and second mixer circuits includes a grounded-emitter differential amplifier, a mixer cell that forms a Gilbert mixer together with a grounded-emitter differential amplifier, a grounded-emitter differential amplifier, and a mixer cell. And a base-grounded differential amplifier inserted between and.

An image rejection mixer according to a third aspect of the present invention has a first polyphase filter having a two-stage structure and divides an input signal into first and second input signals having mutually different phases. A first phase shifter for outputting
A second phase shifter which has a second polyphase filter having a two-stage configuration, and which divides the input local oscillation signal into first and second local oscillation signals having mutually different phases, and outputs the divided signals.
First mixing of a first local oscillator signal and a first input signal
And a second mixer circuit for mixing the second local oscillation signal and the second input signal, and the respective output signals from the first and second mixer circuits are added to obtain a desired frequency. And an adder for outputting a signal.

In the image rejection mixer according to the third aspect of the present invention, the circuits of the first and second stages of the first and second polyphase filters respectively have a signal input terminal and a signal output terminal at both ends. A plurality of input / output lines provided, a plurality of resistance elements arranged on the plurality of input / output lines, and arranged between adjacent input / output lines,
A plurality of capacitive elements each having one end connected to the input end of one input / output line and the other end connected to the output end of the other input / output line, and both ends of each capacitive element in the first polyphase filter And the corresponding connection state of both ends of each capacitive element in the second polyphase filter are arranged so that the input and output are opposite to each other on the input and output lines.

In the image rejection mixer according to the first, second and third aspects of the present invention, due to the function of the first phase shifter, the input signals become the first and second input signals having mutually different phases. It is divided and output. As an input signal to the first phase shifter, for example, an RF signal is input in the case of a receiving system circuit, and an IF signal is input in the case of a transmitting system circuit. Also, the function of the second phase shifter divides the local oscillation signal into first and second local oscillation signals having different phases and outputs the divided signals. Then, the first local oscillation signal and the first input signal are mixed by the first mixer circuit, and the second local oscillation signal and the second input signal are mixed by the second mixer circuit. The respective output signals from the first and second mixer circuits are added by the function of the adder, so that undesired unnecessary signal components are removed and only signals of desired frequencies are output. From the adder, for example, an IF signal in the case of a receiving system circuit,
In the case of a transmission system circuit, an RF signal is output.

Particularly, in the image rejection mixer according to the first aspect of the present invention, in the first and second phase shifters, the connection state of each circuit element of each polyphase filter has a mirror image relationship with each other. By doing so, for example, even if the constants of the circuit elements vary in the manufacturing process of the IC, the phase relationship of the signals output from the first and second phase shifters is compensated. This prevents deterioration of the image rejection characteristic.

Here, in the image rejection mixer according to the first aspect of the present invention, the first phase shifter further includes a differential amplifier integrated with the first polyphase filter at the signal input stage. Have and also second
May further include a differential amplifier integrated with the second polyphase filter at the signal input stage. Further, a grounded base amplifier may be inserted between the first-stage circuit portion and the second-stage circuit portion of the first polyphase filter so as to be integrated with the first polyphase filter. . Further, a grounded base amplifier may be inserted between the first-stage circuit portion and the second-stage circuit portion of the second polyphase filter so as to be integrated with the second polyphase filter. .

Since the first and second polyphase filters are respectively integrated with the amplifier, deterioration of the NF characteristic due to each polyphase filter is prevented,
Power consumption can be reduced.

Particularly, in the image rejection mixer according to the second aspect of the present invention, the first and second mixer circuits each have a configuration in which a grounded differential amplifier is inserted in the Gilbert mixer. As compared with the case of using a normal Gilbert mixer, the distortion component in the grounded-emitter differential amplifier is reduced and the gain is secured. As a result, for example, in the image rejection mixer of the transmission system, improvement of OIP3 is expected.
Further, especially in the image rejection mixer of the receiving system, improvement of IIP3 is expected.

Here, in the image rejection mixer according to the second aspect of the present invention, the first phase shifter has a first polyphase filter having a two-stage configuration, and the second phase shifter is 2 stages. You may have the 2nd polyphase filter of a stage structure. The connection state of each circuit element forming the first-stage circuit of the first polyphase filter and the connection state of each circuit element forming the first-stage circuit of the second polyphase filter are mutually different. The connection state of each circuit element forming the second-stage circuit of the first polyphase filter and the connection state of each circuit element forming the second-stage circuit of the second polyphase filter that are in a mirror image relationship The state and the state may be configured to have a mirror image relationship with each other. As a result, for example, even if the constants of the circuit elements vary in the manufacturing process of the IC, the first and second
The phase relationship of the signal output from the phase shifter is compensated.
This prevents deterioration of the image rejection characteristic.

Further, particularly, in the image rejection mixer according to the third aspect of the present invention, the connection state of both ends of each capacitive element in the first polyphase filter and the corresponding capacitance in the second polyphase filter. Since the connection states of the both ends of the element are configured so that the input and output are opposite to each other on the input and output lines, for example, even if the constant of the circuit element varies in the manufacturing process of the IC, The phase relationship of the signals output from the first and second phase shifters is compensated. This prevents deterioration of the image rejection characteristic.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of a transmission circuit to which an image rejection mixer according to an embodiment of the present invention is applied. The transmission circuit shown in FIG. 1 is applied to, for example, a wireless communication system based on the Bluetooth standard. This transmission circuit includes an image rejection mixer 1, built-in low pass filters (LPF) 2 and 3,
It has a modulator 4 and a local oscillator (OSC) 5.
Each of these circuit elements is provided in one IC chip 10. This transmission circuit also includes a power amplifier (P
A) 6 is provided.

The built-in LPF 2 has a function of filtering a signal of a predetermined frequency component contained in the input I-channel baseband (BB) signal S _I and outputting it to the modulator 4. The built-in LPF 3 has a function of filtering a signal of a predetermined frequency component contained in the input Q-channel baseband signal S _Q and outputting it to the modulator 4. The modulator 4 has a function of modulating a signal input via the built-in LPFs 2 and 3 and outputting it as an IF signal S _IF . The local oscillator 5 has a function of supplying a local (LO) signal S _LO necessary for frequency conversion to the image rejection mixer 1. The power amplifier 6 has a function of amplifying the RF signal S _RF output from the image rejection mixer 1.

The image rejection mixer 1 mixes the IF signal S _IF from the modulator 4 with the local signal S _LO from the local oscillator 5 and converts the frequency to the frequency f _RF.
It has a function of outputting the F signal S _RF . The image rejection mixer 1 also has a function of removing the image signal _SIM generated during frequency conversion.

This image rejection mixer 1 is
The first and second 90 ° phase shifters 11 and 12, the first and second mixer circuits 13 and 14, and the adder 15 are included.

The first 90 ° phase shifter 11 has a function of dividing the IF signal S _IF balanced input from the modulator 4 into two types of balanced signals having different 90 ° phases and outputting the balanced signals. There is. One of the IF signals S _IF divided by the first 90 ° phase shifter 11 (phase 0 °, 180 °)
Is input to the first mixer circuit 13, and the other (phase 90
, 270 °) are input to the second mixer circuit 14. The second 90 ° phase shifter 12 has a function of dividing the local signal S _LO, which has been balanced-input from the local oscillator 5, into two types of balanced signals having mutually different 90 ° phases and outputting the balanced signals. One (phase 0 °, 180 °) of the local signal S _LO divided by the second 90 ° phase shifter 12 is input to the second mixer circuit 14, and the other (phase 90 °, 270 °) is input. , And is input to the first mixer circuit 13. The first and second 90 ° phase shifters 11 and 12 are, as described later,
It is configured by using different types of polyphase filters.

Each of the first and second mixer circuits 13 and 14 receives the IF signal S _IF input via the first 90 ° phase shifter 11 and the second 90 ° phase shifter 12 respectively. mixing the local signal S _LO with a local oscillation frequency f
_It has a function of generating two kinds of signals (having different frequencies) in the upper sideband and the lower sideband with respect to _LO .

The adder 15 adds the respective output signals from the first and second mixer circuits 13 and 14 and removes the image signal S _IM from the RF signal S _RF having a desired frequency.
Is output.

[Specific Example of Circuit Configuration] Next, with reference to FIG. 2, a specific circuit configuration of the image rejection mixer 1 which is a characteristic part of the present embodiment will be described. In this circuit example, the 1 GHz IF signal S _IF is set to 5.25 to 5.3.
It is a circuit that performs upmixing while image rejection to an RF frequency of 5 GHz. In this circuit example, the desired sideband is the upper sideband and the image signal _SIM is the lower sideband.

In this circuit example, the resistors R29 and R30 are used.
Constitute an adder 15. Resistor R27 and transistors Q13, Q14, transistors Q17, Q1
8 and the transistors Q21 to Q24 form a first mixer circuit 13. Resistor R28 and transistors Q15, Q16, transistors Q19, Q20,
Also, the transistors Q25 to Q28 form the second mixer circuit 14.

<Structure of Each Mixer Circuit> In this circuit example, each of the first and second mixer circuits 13 and 14 has a structure in which a base-grounded differential amplifier is added to an ordinary Gilbert mixer. . The Gilbert mixer is roughly divided into a mixer section (mixer cell) and an amplifier section, and the amplifier section usually has a one-stage configuration of a grounded emitter differential amplifier. On the other hand, in the present circuit example, the first and second mixer circuits 13 and 14 are respectively a differential amplifier with a grounded emitter in the lower stage, and a mixer / mixer in the upper stage.
It has cells and has a configuration in which a base-grounded differential amplifier is inserted between the cells. That is, the amplifier section in the Gilbert mixer has a two-stage differential amplifier configuration.

More specifically, in the first mixer circuit 13, the resistor R27 and the transistors Q13 and Q1 are used.
4 forms a grounded emitter differential amplifier section in the Gilbert mixer, and transistors Q21 to Q24 form a mixer cell in the Gilbert mixer.
The transistors Q17 and Q18 form a base-grounded differential amplifier. Constant current sources I5 and I6 are connected to the grounded differential amplifier section of the emitter.

The base terminals of the transistors Q13 and Q14 are connected to the first 90 ° phase shifter 11, and one of the IF signals S _IF divided by the first 90 ° phase shifter 11 (phase 0 °, 180 °). °) is input. The emitter terminals of the transistors Q17 and Q18 are connected to the collector terminals of the transistors Q13 and Q14, respectively. The base terminals of the transistors Q17 and Q18 are connected to each other. Transistors Q21, Q2
The two emitter terminals are mutually connected to the collector terminal of the transistor Q17. Transistors Q23 and Q2
The emitter terminals of 4 are mutually connected to the collector terminal of the transistor Q18.

The base terminals of the transistors Q21 and Q24 are connected to the second 90 ° phase shifter 12 via the capacitor C23.
And one of the local signals S _LO divided by the second 90 ° phase shifter 12 (phase 270 °) is commonly input. On the other hand, transistor Q
The base terminals of 22 and Q23 are connected to the second 90 ° phaser 12 via the capacitor C22, and the second 9 ° phaser 12 is connected.
One of the local signals S _LO divided by the 0 ° phase shifter 12 (phase 90 °) is commonly input.

The collector terminals of the transistors Q21 and Q23 are connected to the transistor Q2 of the second mixer circuit 14.
5, the collector terminal of Q27 and the resistor R of the adder 15
It is connected to one end of 29. Transistors Q21, Q
The output line 51 of the RF signal S _RF is connected to the signal line between the collector terminals of 23, Q25, Q27 and the resistor R29, and one of the balance signals forming the RF signal S _RF is taken out from this connection end. It is like this. On the other hand, the collector terminals of the transistors Q22 and Q24 are connected to one end of the resistor R30 of the adder 15 together with the collector terminals of the transistors Q26 and Q28 in the second mixer circuit 14. Transistors Q22, Q24, Q26, Q
In the signal line between the collector terminal of 28 and the resistor R30,
The output terminal 52 of the RF signal S _RF is connected, and another balance signal constituting the RF signal S _RF is taken out from this connection end.

Further, in the second mixer circuit 14,
The resistor R28 and the transistors Q15 and Q16 form a common-emitter differential amplifier section in the Gilbert mixer, and the transistors Q25 to Q28 form a mixer cell in the Gilbert mixer. The transistors Q19 and Q20 form a base-grounded differential amplifier. The constant current sources I7 and I8 are connected to the lower-emitter grounded differential amplifier section.

The base terminals of the transistors Q15 and Q16 are connected to the first 90 ° phaser 11, and the other (phase 90 °, 270) of the IF signal S _IF divided by the first 90 ° phaser 11 is connected. °) is input. The emitter terminals of the transistors Q19 and Q20 are connected to the collector terminals of the transistors Q15 and Q16, respectively. The base terminals of the transistors Q19 and Q20 are connected to each other. Transistors Q25, Q
The emitter terminals of 26 are mutually connected to the collector terminal of the transistor Q19. Transistors Q27, Q
The emitter terminals of 28 are mutually connected to the collector terminal of the transistor Q20.

The base terminals of the transistors Q25 and Q28 are connected to the second 90 ° phase shifter 12 via the capacitor C24.
, And one of the local signals S _LO (phase 180 °) divided by the second 90 ° phase shifter 12 is commonly input. On the other hand, transistor Q
The base terminals of 26 and Q27 are connected to the second 90 ° phaser 12 via the capacitor C21, and the second 9 ° phaser 12 is connected.
One of the local signals S _LO divided by the 0 ° phase shifter 12 (phase 0 °) is commonly input.

<Structure of Each 90 ° Phaser> The first 90 ° phaser 11 has two stages of polyphase filters 21 and 22, as shown in detail in FIG. . On the other hand, the second 90 ° phase shifter 12 has a two-stage polyphase filter 31 of a kind different from the polyphase filters 21 and 22 in the first 90 ° phase shifter 11 as shown in detail in FIG. , 32. In the first and second 90 ° phase shifters 11 and 12, the polyphase filter has a two-stage configuration. The configuration having only one stage cannot obtain a sufficient image rejection characteristic, and has three stages. This is because in the above configuration, signal loss increases excessively, and it becomes difficult to secure various characteristics other than the image rejection characteristics to the same level as in the conventional case. The configuration and function of the polyphase filters in the first and second 90 ° phase shifters 11 and 12 will be described in detail later.

The first 90 ° phaser 11 further includes a differential amplifier 2 integrated with the polyphase filters 21 and 22.
3 and a grounded base amplifier 24 (FIG. 7).
The first 90 ° phaser 11 further includes a resistor R10 for feeding power.
To R13. A signal output terminal of the first 90 ° phaser 11 is connected to a DC cut capacitor C9.
To C12 (FIG. 2), they are connected to the differential amplifier section in the first and second mixer circuits 13 and 14.

On the other hand, the second 90 ° phaser 12 further includes
It has a differential amplifier 33 and a grounded base amplifier 34 (FIG. 8) integrated with the polyphase filters 31 and 32. The second 90 ° phaser 12 further includes resistors R23 to R26 for power supply. The output terminal of the signal in the second 90 ° phase shifter 12 is connected to the mixer cells in the first and second mixer circuits 13 and 14 via the DC cut capacitors C21 to C24 (FIG. 2). ing.

As described above, the first and second 90 ° phase shifters 11 and 12 each have an active polyphase filter / amplifier configuration in which the amplifier and the two-stage polyphase filter are integrated. . First and second 90 °
The reason why the phase shifters 11 and 12 are integrally configured with the polyphase filter and the amplifier is that the loss of the signal is hard to ignore in the configuration of the polyphase filter alone and it is improved. Compared to the case where the polyphase filter is used alone,
The polyphase filter prevents deterioration of NF characteristics, improves distortion characteristics, and reduces current consumption.

There is a precedent example of a circuit in which a polyphase filter is connected in multiple stages and an NF characteristic is maintained by inserting an independent amplifier that operates independently in the intermediate stage.

FIG. 17 shows a conventional circuit example in which an amplifier is inserted in the intermediate stage of a two-stage polyphase filter. In this circuit, the first-stage polyphase filter 50
1 (resistors R111 to R114 and capacitor C111
To C114), the preamplifier 503 (resistor R21
1 to R213 and transistors Q211 to Q214)
Is provided. In addition, the first-stage polyphase filter 501 and the second-stage polyphase filter 502 (resistors R121 to R124 and capacitors C121 to C12).
4) (intermediate stage), an amplifier 504 (resistor R411
To R413 and transistors Q411 to Q414)
And an amplifier 505 (resistors R311 to R313 and transistors Q311 to Q314).

As described above, in the conventional circuit, the two types of balance signals (phase 0 °, 180 ° and phase 90 °, 270) output from the first-stage polyphase filter 501 are used.
2), two independent cascode amplifiers 504 and 505 for balanced input / output are inserted.

On the other hand, the structure of this circuit (FIGS. 7 and 8) is characterized in that the amplifier is integrated with the two-stage polyphase filter. This circuit has a configuration of "differential amplifier → poly phase filter → grounded base amplifier → poly phase filter" from the signal input side. The phase filter also serves as a load.

As a result, the individual amplifiers 5 are compared with the normal circuit in which the polyphase filters 501 and 502 and the cascode amplifiers 504 and 505 of FIG. 17 are combined.
The load resistors 04 and 505 (the resistors R412 and R413 and the resistors R312 and R313) can be removed from the constituent elements, and the transmission efficiency of the signal amplified by the transistor is increased. Even in the polyphase filter / amplifier of this circuit, the four power feeding resistors R10 to R1 are provided in the uppermost stage.
3 (FIG. 7) and resistors R23 to R26 (FIG. 8) are used. The resistance of these power supply resistors is set higher than that of a normal intermediate stage amplifier, thereby reducing the signal loss due to the power supply resistors.

Further, in the conventional circuit, the current source is independently required for the amplifier in the intermediate stage, whereas in this circuit, the amplifier is shared, so that the required current is reduced. There is. However, the overall gain is higher when an independent cascode amplifier is used in the intermediate stage. However,
From the viewpoint of maintaining the NF characteristic, a sufficient gain can be obtained with the configuration of this circuit.

Next, the first and second 90 ° phase shifters 1
The circuit configuration of each of the parts 1 and 12 will be specifically described. First, the differential amplifier 23 in the first 90 ° phaser 11 is provided in the input stage of the IF signal S _IF . The differential amplifier 23 includes a resistor R1 and a transistor Q1,
It is configured to have Q2. The constant current sources I1 and I2 are connected to the differential amplifier 23. Transistor Q
The IF signals S _IF are balancedly input to the base terminals of 1 and Q2. The collector terminals of the transistors Q1 and Q2 are respectively the first-stage polyphase filter 2
1 is connected to the input terminal.

The grounded base amplifier 24 (FIG. 7) in the first 90 ° phaser 11 is provided between the first-stage polyphase filter 21 and the second-stage polyphase filter 22. The grounded base amplifier 24 is configured to have transistors Q3 and Q4 and transistors Q5 and Q6.

The base terminals of the transistors Q3 and Q4 are connected to each other. The emitter terminals of the transistors Q3 and Q4 are the first-stage polyphase filter 21 respectively.
Are connected to one ends (output ends of the polyphase filter 21) of the resistors R2 and R4 which are the constituent elements of the above. The collector terminals of the transistors Q3 and Q4 are resistors R6 and R8, which are constituent elements of the second-stage polyphase filter 22, respectively.
Is connected to one end (the input end of the polyphase filter 22).

On the other hand, the base terminals of the transistors Q5 and Q6 are connected to each other. The emitter terminals of the transistors Q5 and Q6 are respectively connected to one ends (output ends of the polyphase filter 21) of resistors R3 and R5 which are constituent elements of the polyphase filter 21 of the first stage. The collector terminals of the transistors Q5 and Q6 are resistors R, which are the constituent elements of the second-stage polyphase filter 22, respectively.
7, one end of R9 (input end of polyphase filter 22)
It is connected to the.

The differential amplifier in the second 90 ° phase shifter 12
33 (FIG. 8) is the local signal S _LOProvided at the input stage of
Has been. The differential amplifier 33 includes a resistor R14 and a transistor
It is configured to have transistors Q7 and Q8. Differential
The constant current sources I3 and I4 are connected to the pump 33.
Local signals are connected to the base terminals of the transistors Q7 and Q8.
Issue S_LOAre balanced input. Transis
The collector terminals of Q7 and Q8 are
It is connected to the input terminal of the phase filter 31.

The grounded base amplifier 34 in the second 90 ° phaser 12 is provided between the first-stage polyphase filter 31 and the second-stage polyphase filter 32. The grounded base amplifier 34 includes a transistor Q1.
1, Q12 and transistors Q9, Q10.

The base terminals of the transistors Q11 and Q12 are connected to each other. Transistors Q11, Q12
The respective emitter terminals of are connected to one ends (output ends of the polyphase filter 31) of the resistors R15 and R18 which are the constituent elements of the polyphase filter 31 of the first stage. The collector terminals of the transistors Q11 and Q12 are respectively connected to one ends (input ends of the polyphase filter 32) of resistors R19 and R18 which are constituent elements of the second-stage polyphase filter 32.

On the other hand, the base terminals of the transistors Q9 and Q10 are connected to each other. Transistors Q9 and Q1
The emitter terminals of 0 are respectively connected to one ends (output ends of the polyphase filter 31) of the resistors R16 and R17 which are components of the polyphase filter 31 of the first stage. The collector terminals of the transistors Q9 and Q10 are respectively connected to one end (polyphase filter 3) of resistors R20 and R21 which are constituent elements of the second-stage polyphase filter 32.
2 input terminal).

<Structure and Function of Polyphase Filter> Next, the structure and function of the polyphase filter in the first and second 90 ° phase shifters 11 and 12 will be described.

FIG. 3 shows only the polyphase filters 21 and 22 extracted from the circuit elements of the first 90 ° phaser 11. In addition, FIG. 4 shows the second 90 °
From the circuit element of the phase shifter 12 to the polyphase filter 31,
Only the 32 part is extracted and shown.

The first polyphase filter 21 in the first 90 ° phaser 11 (FIG. 3) has four resistors R2.
To R5 and four capacitors C1 to C4. Similarly, the second-stage polyphase filter 22 also has four resistors R6 to R9 and four capacitors C5 to C8.

The first-stage polyphase filter 21 also has two input terminals 61 and 62 and four output terminals. The second-stage polyphase filter 22 has four
It has one input terminal and four output terminals 63 to 66. Although illustration of the terminals is omitted in FIG. 3, the four output terminals of the first-stage polyphase filter 21 and the four input terminals of the second-stage polyphase filter 22 are connected to each other.

In the polyphase filter 22 of the second stage, the resistors R6 to R9 are four input / output lines 67 to 7 connecting the input terminals and the output terminals 63 to 66, respectively.
It is located on 0. Four capacitors C5-C8
Are arranged between the adjacent lines of the four input / output lines 67-70, and the input / output lines 67-7 are different at both ends.
0 is connected to the input terminal or the output terminal.

That is, one end of the resistor R6 and one end of the capacitor C5 are connected to the input end of the first input / output line 67, and the other end of the resistor R6 and the capacitor C8 are connected to the output end.
Is connected to the other end of. Also, one end of the resistor R7 and one end of the capacitor C6 are connected to the input end of the second input / output line 68, and the other end of the resistor R7 and the other end of the capacitor C5 are connected to the output end. There is. Further, one end of the resistor R8 and one end of the capacitor C7 are connected to the input end of the third input / output line 69, and the other end of the resistor R8 and the other end of the capacitor C6 are connected to the output end. There is. Further, one end of the resistor R9 and one end of the capacitor C8 are connected to the input end of the fourth input / output line 70, and the other end of the resistor R9 and the other end of the capacitor C7 are connected to the output end. There is. In this way, one input terminal is cyclically coupled to two output terminals via one resistor and one capacitor. For example, the input terminal of the first input / output line 67 is
Of the output terminal 63 and the second output terminal 64 via the capacitor C5.

The first-stage polyphase filter 21 has basically the same structure as the second-stage polyphase filter 22, and the four resistors R2 to R5 are respectively
It is arranged on the four input / output lines 67 to 70, and
The four capacitors C1 to C4 are the four input / output lines 67.
˜70 between adjacent lines. The structure is different from the second-stage polyphase filter 22 in that the input ends of the first and second input / output lines 67 and 68 are combined as one input terminal 61, and the third and fourth input / output lines are connected. The input ends of the lines 69 and 70 are connected as one input terminal 62.

The first-stage polyphase filter 31 in the second 90 ° phaser 12 (FIG. 4) is also the first-stage polyphase filter 21 in the first 90 ° phaser 11.
Similar to (FIG. 3), it has four resistors R15 to R18 and four capacitors C13 to C16. Similarly, the second-stage polyphase filter 32 has four resistors R19-
It has R22 and four capacitors C17 to C20.

The first-stage polyphase filter 31 has two input terminals 7 similarly to the first-stage polyphase filter 21 (FIG. 3) in the first 90 ° phaser 11.
1, 72 and four output terminals. The second-stage polyphase filter 32 is also the first 90 ° phaser 11
4 as with the second-stage polyphase filter 22 in
It has one input terminal and four output terminals 73 to 76. Although the terminals are not shown in FIG. 4, the four output terminals of the first-stage polyphase filter 31 and the four input terminals of the second-stage polyphase filter 32 are connected to each other.

In the second-stage polyphase filter 32, the resistors R19 to R22 have respective input terminals and output terminals as in the first-stage polyphase filter 21 (FIG. 3) in the first 90 ° phaser 11. It is arranged on four input / output lines 77 to 80 which connect 73 to 76. Similarly to the first 90 ° phaser 11, the four capacitors C17 to C20 are also arranged between adjacent lines of the four input / output lines 77 to 80, and the input and output lines 77 to 77 having different ends are formed.
It is connected to the input terminal or the output terminal of 80.

First and second 90 ° phase shifters 11, 12
The second-stage polyphase filters 22 and 32 in
The connection state of each circuit element has a mirror image relationship with each other. Then, the connection state of both ends of each capacitor is in the input / output reverse state on the input / output line. For example, the first
Focusing on the connection state of the capacitors arranged between the first and second input / output lines, in the first 90 ° phaser 11, one terminal of the capacitor C5 is provided at the “input end of the first input / output line 67”. And the other terminal of the capacitor C5 is connected to the "output terminal of the second input / output line 68". On the other hand, in the second 90 ° phaser 12,
One terminal of the capacitor C17 corresponding to the capacitor C5 is connected to the “output terminal of the first input / output line 77”,
The other terminal is connected to the "input terminal of the second input / output line 78". The same applies to the capacitors arranged between the other input / output lines as well as the polyphase filters 22, 32.
In, the connection states of both ends of the corresponding capacitors are input and output opposite to each other.

The first-stage polyphase filter 31 basically has the same structure as the second-stage polyphase filter 32, and the four resistors R15 to R18 are connected to the four input / output lines 77 to 80. The four capacitors C13 to C16 arranged above are connected to the four input / output lines 77 to
Located between adjacent lines at 80. The structure is different from the second-stage polyphase filter 32 in that
The input ends of the first and second input / output lines 77 and 78 are
The input ends of the third and fourth input / output lines 79 and 80 are combined as one input terminal 71 and one input terminal 7 is connected.
It is a point that is connected as 2.

First and second 90 ° phase shifters 11, 12
Similarly to the second-stage polyphase filters 31 and 32 in the first-stage polyphase filters 21 and 31, the connection state of each circuit element is in a mirror image relationship with each other. Then, the connection states of both ends of the corresponding capacitors are opposite to each other on the input / output line.

Thus, in this circuit, the first and second
Two types of polyphase filters (FIGS. 3 and 4) are used for the 90 ° phase shifters 11 and 12. Comparing these two types of polyphase filters, the input states of the balance signals are opposite because the connection states of the respective circuit elements are in a mirror image relationship with each other. This is a polyphase filter of the same kind in topology,
It can be said that the input direction of the balance signal is simply reversed.

In this circuit, by properly combining the above two types of polyphase filters, the image rejection characteristic can be maintained well. The principle by which the image rejection characteristic can be maintained will be described below. Below, for convenience,
The first polyphase filter shown in FIG. 3 is called A type, and the second polyphase filter shown in FIG. 4 is called B type as appropriate.

In the first polyphase filter shown in FIG. 3, when a balanced signal of a desired frequency is input to the two input terminals 61 and 62, its four output terminals 63 to 66 are provided.
, Four signals having the same amplitude and a phase difference of 90 ° are output. At this time, the output phase rotation direction is counterclockwise as shown in FIG. 5 (A). On the other hand, also in the second polyphase filter shown in FIG. 4, when the balance signal of the desired frequency is input to the two input terminals 71 and 72, the amplitudes are equal and the phases are equal from the four output terminals 73 to 76. Four signals shifted by 90 ° are output. At this time, when the output phase rotation direction is illustrated, as shown in FIG. 5B, it is a clockwise direction, which is the opposite direction to the A type.

In this way, the output phase rotation directions of the A type and the B type are just opposite. In this case, as long as the resistance value R and the capacitance value C of each polyphase filter do not vary with respect to the design value, the characteristics of both types are 90 ° although the phase rotation direction of each terminal is opposite. There is no difference in terms of outputting signals that are out of phase. Therefore, under the condition that there is no variation in the constant, the first and second 90 ° phase shifters 11 and 12 are
The image rejection characteristics are the same whether the type A or the type B is used.

On the other hand, when the constants vary,
A shift in the phase rotation angle occurs in each polyphase filter. However, the types A and B are different in the direction of the phase rotation angle shift (see FIGS. 5B and 6B). Inside the IC, resistance value R and capacitance value C
The relative error is very small, and all the elements often scatter to almost the same size at the same time.
Under such a condition, the phase rotation angle deviations of the A type and B type have the same absolute value of deviation and opposite directions.

Therefore, in the case of the up-mixer of "RF output frequency> local frequency> IF input frequency", as in this circuit, the A type is provided on the input side (first 90 ° phaser 11) of the IF signal S _IF. By using the B type polyphase filter on the input side (the second 90 ° phaser 12) of the local signal S _LO , it is possible to maintain the image rejection characteristic with respect to the variation in the constants of the circuit elements. Specifically, for example, the resistance value R and the capacitance value C are set to 2 in the same direction.
Image rejection characteristics when 0% variation is 3
It becomes possible to secure 0 dB or more. Further, in the case of the down mixer of “RF input frequency> local frequency> IF output frequency”, by using the A type for both phase shifters, the image rejection characteristic can be maintained similarly. As described above, in order to maintain the image rejection characteristic by combining the phase shifter with a two-stage poly-phase filter, two types of A-type or B-type polys are used for the combination of the input signal and the local signal. Properly select the phase filter combination pattern. As a result, it is possible to maintain the image rejection capability when the constants vary, without distinguishing between the up mixer and the down mixer.

It should be noted that a configuration in which an RC filter and a polyphase filter are combined, that is, the first 90 ° phase shifter 11 is used as an RC filter (or polyphase filter)
In the case where the second 90 ° phase shifter 12 is configured by a polyphase filter (or RC filter), an excellent image rejection function such as the image rejection mixer 1 according to the present invention is applied to the variation in the constants of the circuit elements. Function characteristics cannot be obtained. Also, the first and second 90
° When the phase shifters 11 and 12 are configured with three or more stages of polyphase, the signal loss in the phase shifter increases excessively,
It becomes difficult to secure various characteristics other than the image rejection characteristics to the same level as conventional ones.

Next, the operation of the transmission circuit according to this embodiment will be described.

In the transmission circuit shown in FIG. 1, the I-channel baseband (BB) signal S _I is balanced-input to the built-in LPF 2. Further, the Q-channel baseband signal S _Q is balanced-input to the built-in LPF 3. The built-in LPFs 2 and 3 are
A predetermined frequency component of the input signals S _I and S _Q is output to the modulator 4. The modulator 4 modulates the signal input via the built-in LPFs 2 and 3 and outputs the IF signal S _IF in a balanced manner. The image rejection mixer 1 includes an IF signal S _IF from the modulator 4 and a local signal S _LO from the local oscillator 5.
RF signal S that is mixed with and converted to frequency f _RF
Balanced output of _RF . The image signal _SIM generated during frequency conversion is removed by the function of the image rejection mixer 1. The power amplifier 6 amplifies and outputs the RF signal S _RF output from the image rejection mixer 1.

In the image rejection mixer 1, the first 90 ° phase shifter 11 has an IF from the modulator 4.
The signal S _IF is input. At this time, the first 90 ° phaser 1
The signal input to 1 is balanced. That is, 180
A pair of balance signals having different phases are input as the IF signal S _IF . The first 90 ° phase shifter 11 divides the input IF signal S _IF into two types of balanced signals that are 90 ° phase-shifted and outputs them. One of the divided IF signals S _IF (phase 0 °, 180 °) is input to the first mixer circuit 13. Other (phase 90 °, 270 °)
Is input to the second mixer circuit 14.

On the other hand, the local signal S _LO from the local oscillator 54 is input to the second 90 ° phaser 12. At this time, the signal input to the second 90 ° phase shifter 12 is performed in a balanced manner. That is, a pair of balance signals having 180 ° different phases are input as the local signal S _LO . Second 9
The 0 ° phase shifter 12 _{controls the} input local signal S _LO by 90 degrees.
° Divided into two types of phase-shifted balanced signals and output. One of the divided local signals S _LO (phase 0 °, 180 °) is input to the second mixer circuit 14. The other (phase 90 °, 270 °) is input to the first mixer circuit 13.

The first mixer circuit 13 receives the IF signal S _IF input via the first 90 ° phase shifter 11 and the second 9
The local signal S _LO input through the 0 ° phase shifter 12 is mixed to generate two kinds of signals (having different frequencies) in the upper sideband and the lower sideband with respect to the local oscillation frequency f _LO . . The second mixer circuit 14 similarly mixes the IF signal S _IF and the local signal S _LO to generate two kinds of signals in the upper sideband and the lower sideband with respect to the local oscillation frequency f _LO . The two types of signals generated by the first and second mixer circuits 13 and 14 are output to the adder 15. At this time, if the phase relationship between the two types of signals output from the first mixer circuit 13 and the two types of signals output from the second mixer circuit 14 is appropriately adjusted, the upper and lower sidebands Of these, only the desired signal component can be output from the adder 15 as the desired RF signal S _RF . That is, the desired signal component is passed through the adder 15 in phase. On the other hand, other undesired signal components, that is, the image signal S _IM , are canceled and eliminated by reversing the phase relationship.

Next, the operation of the image rejection mixer 1 in the specific circuit configuration shown in FIG. 2 will be described.

In the circuit example of FIG. 2, the first 90 ° phase
IF signal S balanced input to the device 11 _IFIs shown in FIG.
Like this, first amplified in the differential amplifier 23, then
90 ° phase in the first-stage polyphase filter 21
To be distributed. This distributed IF signal S_IFIs
It is amplified by the grounded ground amplifier 24 and is
It is input to the waze filter 22. Second stage polyphase
In the filter 22, the input signal is read by about 90 °.
Distribute the phases. IF signal S distributed_IFFor DC cut
Via capacitors C9-C12 (FIG. 2) of
It is output to the amplifier section of the second mixer circuits 13 and 14.

As described above, in the first 90 ° phaser 11,
By performing the operation "differential amplifier → polyphase filter → grounded base amplifier → polyphase filter → signal output", IIP3 and NF are secured at the same time. More specifically, the first 90 ° phase shifter 11 has a polyphase filter inserted therein, which is different from the configuration of a normal cascode amplifier that operates VI conversion at the stage of a differential amplifier. It operates as a normal differential amplifier and secures its IIP3. Further, by inserting a grounded base amplifier between the first-stage polyphase filter 21 and the second-stage polyphase filter 22, it is possible to prevent the signal level from being lowered due to the polyphase filters 21 and 22. Is maintained. At this time, since the grounded base amplifier is used in the intermediate stage, the voltage gain corresponding to the input / output impedance ratio of the grounded base portion is gained while the current does not change. We compensate for the drop.

Here, the performance of the active type polyphase filter amplifier (FIG. 7) that constitutes the first 90 ° phase shifter 11 alone is Zs = 600Ω, Z1 = 600Ω × 2 (phase 0 °, 90 ° Under each condition, the simulation results are as follows. Zs is the signal source impedance. Z1 is a load impedance, and each balance signal (phase 0 °, 180 ° and phase 9
0 °, 270 °) is 600Ω. The IF frequency is 1 GHz. NF is a noise figure, PG
Indicates the power gain. IIP3 indicates an input intercept point.

Vcc = 2.8V Icc = 1.5mA Zs = 600Ω Zl = 600Ω (0 °, 90 ° individual) IIP3 = -7.5 dBm NF = 4.5 dB PG = 1.6dB (0 °, 90 ° individual)

I output from the first 90 ° phase shifter 11
As shown in FIG. 2, the F signal S _IF is input to the first and second mixer circuits 13 and 14, and is amplified by a two-stage differential amplifier of grounded emitter and grounded base. In a normal Gilbert mixer, the input amplifier section is composed of only one stage of a differential amplifier with a grounded emitter. In contrast,
In this circuit, a base-grounded differential amplifier (transistor Q1
7, Q18 and transistors Q19, Q20) are added to form an input amplifier section. In this grounded-base differential amplifier, by selecting an appropriate cell size, bias potential, etc., distortion components in the grounded-emitter differential amplifier can be reduced and gain can be secured as compared to a normal Gilbert mixer. Done. This is expected to improve OIP3 when used in the image rejection mixer of the transmission system.

In this circuit example, a large-sized transistor is inserted as a base-grounded differential amplifier.
As a result, the input / output signal levels of the base-grounded differential amplifier are made different from each other, and the differential amplifier section is made to have a power gain due to the signal level difference. As a result, the lower grounded-emitter differential amplifier section operates like a VI conversion amplifier like a normal Gilbert mixer differential amplifier, while the intermediate base-grounded amplifier provides a power gain. CG (conversion gain) of the entire mixer circuit is increased without deteriorating the characteristics of the lower differential amplifier. OIP3
Can be increased. In this circuit, the insertion of the grounded differential amplifier results in a simulation result that the OIP3 is improved by 3 dB or more as compared with the case where the grounded differential amplifier is not provided.

On the other hand, the second 90 ° phase shifter 12 performs the same operation on the balanced input local signal S _LO as the IF signal S _IF balanced input to the first 90 ° phase shifter 11. . That is, the input local signal S _LO is first amplified by the differential amplifier 33 as shown in FIG.
Next, in the first-stage polyphase filter 31, 90
° Phase distributed. This distributed local signal S
_LO is further amplified by the grounded base amplifier 34,
It is input to the second-stage polyphase filter 32. The polyphase filter 32 of the second stage again divides the input signal by 90 °. Distributed local signal S
_LO is output to the mixer cells (transistors Q21 to Q28) of the first and second mixer circuits 13 and 14 via the DC cut capacitors C21 to C24 (FIG. 2).

Also in the second 90 ° phase shifter 12, the first
Like the 90 ° phase shifter 11 of FIG. 1, the cascode amplifier and the two-stage polyphase filter are combined by the configuration of the active polyphase filter / amplifier in which the amplifier and the two-stage polyphase filter are integrated. It is superior in terms of output power, etc., compared to the combined normal configuration.

The local signal S _LO and the IF signal S _IF input to the first and second mixer circuits 13 and 14 are mixed in the transistors Q21 to Q28 as shown in FIG. Then, the desired wave is output as the RF signal S _RF through the adder 15 with the in-phase component. The image signals _SIM are opposite phase components and are canceled and eliminated.

<Simulation Data> Next, specific performance data of the image rejection mixer 1 (FIG. 2) will be simulated and shown. In addition, Type. The constant-time in-band characteristic refers to the characteristic when the constant of each circuit element is a value as designed. CG represents conversion gain, and NF represents noise figure. I
IP3 represents an input intercept point. Constant 2
Image rejection at 0% fluctuation means that the resistance value and the capacitance value of each polyphase filter in the first and second 90 ° phase shifters 11 and 12 are in the same direction (plus or minus) with respect to the design value. Represents the value of the image rejection characteristic when a 20% variation occurs.

RF signal output: 5.15 G to 5.35 GH
z LO signal input ... 4.25 GHz to 4.35 GHz IF signal input ... 1 GHz <Typ. In-band characteristic at constant time> LO signal input: -16 dBm CG ... 12 dB NF ... 6 dB IIP3 ...- 10 dBm Image rejection ... 42 dB Image rejection when constant 20% changes:> 34 d
B Vcc = 2.8V Icc = 10.5mA

As can be seen from the results of the above simulation data, the image rejection mixer 1 of the present invention can obtain good image rejection characteristics with respect to variations in the constants of the circuit elements, and other signal characteristics (particularly , Gain, NF and IIP3) were also good values.

<Effects of the Present Embodiment> As described above, according to the present image rejection mixer 1, it is possible to provide an image rejection mixer having stable performance and superior performance as compared with the conventional one. You can In particular, since the first and second mixer circuits 13 and 14 each have a Gilbert mixer configuration in which a grounded base differential amplifier is inserted, the amplifier section is usually a grounded emitter differential amplifier. In particular, the distortion characteristics can be improved and OIP3 can be improved as compared with the Gilbert mixer.

Further, in particular, the first and second phase shifters 11,
12 with different types of polyphase filters (Fig. 3,
(See FIG. 4), the deviation of the phase rotation angle in each polyphase filter is generated in the opposite direction when the constants vary, and the first and second phase shifters 11,
Since the phase relationship of the signal output from 12 is compensated, good image rejection characteristics can be maintained against variations in the constants of the circuit elements.

In addition, the first and second phase shifters 11 and 12
Since the amplifier is configured as an active polyphase filter / amplifier in which an amplifier and a two-stage polyphase filter are integrated, a polyphase filter alone can be used without adding an amplifier having a different configuration from the polyphase filter. Compared with the case of being configured, it is possible to prevent the deterioration of the NF characteristic due to the polyphase filter, and to reduce the power consumption. In particular, in each phaser, the grounded base amplifier 2 integrated with the polyphase filter is provided between the first-stage circuit portion and the second-stage circuit portion of the polyphase filter.
4, 34 (Figs. 7 and 8) were inserted, so N
The F characteristic can be further improved. Then, it is possible to prevent the signal loss from being reduced by the polyphase filter and improve the distortion characteristic.

As described above, according to the image rejection mixer 1, good image rejection characteristics can be maintained against variations in the constants of the circuit elements, and other signal characteristics are similar to those of the conventional one. Or it can maintain higher performance. Specifically, even if the resistance value and the capacitance value of each polyphase filter vary by 20% in the same direction with respect to the design value, the performance of the conventional level with respect to the gain, NF, and IIP3 is maintained, and , The image rejection characteristics exceeding 34 dB can be maintained. Further, in the case where the image-rejection mixer 1 is used to configure a transmitter made into an IC, an external filter can be removed from the configuration of the transmitter, and the circuit can be downsized. Further, since good image rejection characteristics can be maintained against variations in the constants of circuit elements, the yield of ICs can be improved.

[Modification] Next, a modification of the circuit configuration of the image rejection mixer 1 shown in FIG. 2 will be described. The modified example described below is different only in the configuration from the circuit example shown in FIG. 2, and the operation and operation of the entire circuit is basically the same as that of the circuit example shown in FIG. Is the same.

FIG. 11 shows a first modification of the image rejection mixer 1. In this modified example, FIG.
The first and second mixer circuits 13 and 14 and the first 90 ° phase shifter 11 are partially different in configuration from the circuit shown in FIG. In this modification, a circuit portion 1 corresponding to the first and second mixer circuits 13 and 14 in FIG.
3A and 14A are mixers at Gilbert mixer.
Only the core portion (transistors Q21 to Q28) is provided. In addition, the first 90 ° phase shifter 11 in the present modification example
A is compared with the first 90 ° phaser 11 in FIG.
Capacitors C9 to C12 for DC cut and power supply resistor R
10 to R13 (FIG. 7) are omitted. That is, in the present modification, the Gilbert mixer amplifier unit is replaced by the active polyphase filter shown in FIG.
It has a configuration in which an amplifier is substituted.

The image rejection mixer according to the present modification has a higher Vcc than that of the configuration shown in FIG. 2 and is a circuit suitable for a configuration in which there is a margin in the collector voltage Vce of each transistor. It should be noted that, with respect to the circuit configuration of FIG. 2, the constants of individual circuit elements, the cell size, and the like need to be readjusted.

FIG. 12 shows a second modification of the image rejection mixer 1. In this modified example, FIG.
The first and second mixer circuits 13 and 14 and the first 90 ° phase shifter 11 are partially different in configuration from the circuit shown in FIG. The circuit portion 13B in this modification,
14B is the first and second mixer circuits 1 in FIG.
3 and 14, the lower emitter-grounded differential amplifier (resistor R27 and transistors Q13 and Q14, and resistor R28 and transistors Q15 and Q16) is omitted. In addition, the first 9 in this modification
The 0 ° phase shifter 11A is different from the first 90 ° phase shifter 11 in FIG. 2 in that DC cut capacitors C9 to C12 are provided.
The power supply resistors R10 to R13 (FIG. 7) are omitted. That is, in this modification, the active polyphase filter / amplifier shown in FIG. 7 is used in place of the lower emitter-grounded differential amplifier in FIG.

The image rejection mixer of this modification has a higher Vcc than the structure of the first modification of FIG. 11, and has a circuit suitable for a structure having a margin in the collector voltage Vce of each transistor. Become. In addition, with respect to the circuit configuration of FIG. 2, constants of individual circuit elements,
Of course, the cell size etc. need to be readjusted.

Which of the modified examples shown in FIGS. 11 and 12 is to be adopted is appropriately selected according to the power supply voltage condition of the circuit.

FIGS. 9 and 10 are modifications of the active polyphase filter amplifiers (first and second 90 ° phase shifters 11 and 12) shown in FIGS. 7 and 8, respectively.

The active polyphase filter amplifier shown in FIG. 9 differs from the circuit shown in FIG. 7 in the parts of the differential amplifier 23 and the grounded base amplifier 24. In the circuit shown in FIG. 7, transistors are used in these parts, but in the circuit shown in FIG. 9, a MOS (Metal Oxide) is used.
Semiconductor) -FET (Field Effect Transistor)
Is used. That is, in this modification, the transistors Q1 and Q2 (differential amplifier 23) in the circuit shown in FIG.
And the transistors Q3 to Q6 (base grounded amplifier 24) are respectively connected to the MOS elements T1 and T2 (differential amplifier 23).
A) and MOS elements T3 to T6 (grounded base amplifier 24)
The configuration is replaced with A).

Similarly, in the active polyphase filter / amplifier shown in FIG. 10, MOS-F is used instead of the transistor.
ET is used. That is, this modification is similar to the transistor Q7, Q8 (differential amplifier 3 in the circuit shown in FIG.
3) and transistors Q9 to Q12 (grounded base amplifier 3
4) is replaced with MOS elements T7 and T8 (differential amplifier 33A) and MOS elements T9 to T12 (base ground amplifier 34A), respectively.

By using the MOS-FET as in the modification shown in FIGS. 9 and 10, the cost can be reduced when the circuit is formed into an IC chip.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, the active polyphase filter amplifier and mixer circuit of the present invention,
In addition, the image rejection mixer is not limited to the transmission circuit having the configuration shown in FIG. 1 and can be widely applied to the transmission system circuit portion in various radio communication systems using the RF band. Further, the present invention is applicable not only to the circuit of the transmission system but also to the receiving circuit. When applied to the receiving circuit, the IIP3 can be particularly improved. When applied to the receiving circuit, the received RF signal is input to the first 90 ° phaser 11, and the IF signal is output from the adder 15.

The active polyphase filter / amplifier of the present invention is not limited to the phase shifter of the image rejection mixer, but can be used in other circuits. For example, QPSK (Quadriphase Phase Shift Keyi
It is also applicable to ng) type modulators and the like.

[0136]

As described above, according to claims 1 to 3,
The active polyphase filter according to any one of 1.
According to the amplifier, since the differential amplifier is provided in the signal input stage so as to be integrated with the polyphase filter having the two-stage configuration, it is possible to add an amplifier having a configuration different from that of the polyphase filter, In particular, it is possible to prevent the deterioration of the NF characteristic due to the polyphase filter and reduce the power consumption. As a result, for example, it can be used in the phase shifter part of the image rejection mixer or the phase shifter part of the QPSK quadrature modulator, and the performance thereof can be improved.

Particularly, according to the mixer circuit of the second aspect, in the mixer circuit of the first aspect, a polyphase filter is provided between the first-stage circuit portion and the second-stage circuit portion of the polyphase filter. Since the integrated grounded base amplifier is inserted, the NF characteristic can be further improved. Further, it is possible to prevent the signal loss from being reduced by the polyphase filter and improve the distortion characteristic.

According to the mixer circuit of the fourth aspect, the grounded-base differential amplifier is inserted between the grounded-emitter differential amplifier and the mixer cell that form the Gilbert mixer. In particular, the distortion characteristics can be improved. Further, especially when used in a transmission system image rejection mixer, OIP3 can be improved. In particular, when used in the mixer circuit part of the image rejection mixer of the receiving system, the IIP
3 can be improved.

Further, according to the image rejection mixer of any one of claims 5 to 7, the first and second phase shifters have first and second polyphase filters each having a two-stage configuration. And the connection state of each circuit element forming the first-stage circuit of the first polyphase filter and the connection state of each circuit element forming the first-stage circuit of the second polyphase filter are , Which are in a mirror image relationship with each other, of the connection state of each circuit element forming the second-stage circuit of the first polyphase filter and the connection state of each circuit element forming the second-stage circuit of the second polyphase filter. Since the connection state and the connection state are mirror images of each other, it is possible to realize an image rejection mixer with stable performance and excellent performance as compared with the conventional case. Especially the first
Since the second phase shifter uses different types of polyphase filters that compensate the phase relationship of the signals output from the first and second phase shifters, it is possible to reduce the variation in the constants of the circuit elements. It is possible to maintain good image rejection characteristics.

Particularly, according to the image rejection mixer of the sixth or seventh aspect, since the first and second polyphase filters are integrated with the amplifier, respectively, the NF characteristic of each polyphase filter is particularly high. Can be prevented and power consumption can be reduced.

According to the image rejection mixer of the eighth or ninth aspect, the first and second mixer circuits respectively include a grounded emitter differential amplifier and a grounded emitter differential amplifier together with a Gilbert mixer. It has a mixer cell that composes, and a grounded differential amplifier that is inserted between the grounded emitter differential amplifier and the mixer cell, so the performance is more stable than before. In addition, it is possible to realize an image rejection mixer with excellent performance. In particular, the insertion of the base-grounded differential amplifier can particularly improve the distortion characteristic. Further, especially in the case of a transmission system, OIP3 can be improved. In the case of a receiving system, I
IP3 can be improved.

Particularly, according to the image rejection mixer of the ninth aspect, in the image rejection mixer of the eighth aspect, the first and second phase shifters output the first and second phase shifters. Since different types of polyphase filters are used so that the phase relationship of the signals
It is possible to maintain a good image rejection characteristic, and it is possible to maintain the performance equivalent to or higher than that of the related art with respect to other signal characteristics.

According to the image rejection mixer of the tenth aspect, the first and second phase shifters have the first and second poly-phase filters each having a two-stage configuration, and the first poly-phase filter has the first poly-phase filter. The connection state of both ends of each capacitance element in the phase filter and the corresponding connection state of both ends of each capacitance element in the second poly-phase filter are arranged so that they are in an input / output opposite state on the input / output line. By doing so, it is possible to realize an image rejection mixer having stable performance and excellent performance as compared with the conventional one. In particular, since the first and second phase shifters use different types of polyphase filters that compensate the phase relationship of the signals output from the first and second phase shifters, the constants of the circuit elements are constant. It is possible to maintain a good image rejection characteristic with respect to the variation of.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a transmission circuit to which an image rejection mixer according to an embodiment of the present invention is applied.

FIG. 2 is a circuit diagram showing a specific configuration of an image rejection mixer according to an embodiment of the present invention.

FIG. 3 is a circuit diagram for explaining a function of a polyphase filter which constitutes a first 90 ° phaser in the image rejection mixer shown in FIG.

FIG. 4 is a circuit diagram for explaining a function of a polyphase filter which constitutes a second 90 ° phaser in the image rejection mixer shown in FIG.

FIG. 5 is an explanatory diagram showing a phase rotation angle of a signal output from a polyphase filter which constitutes a first 90 ° phaser.

FIG. 6 is an explanatory diagram showing a phase rotation angle of a signal output from a polyphase filter which constitutes a second 90 ° phaser.

7 is a circuit diagram showing a configuration of a first 90 ° phaser in the image rejection mixer shown in FIG.

8 is a circuit diagram showing a configuration of a second 90 ° phaser in the image rejection mixer shown in FIG.

FIG. 9 is a circuit diagram showing a modification example of the first 90 ° phaser shown in FIG. 7.

10 is a circuit diagram showing a modified example of the second 90 ° phaser shown in FIG.

11 is a circuit diagram showing a first modification of the image rejection mixer shown in FIG.

FIG. 12 is a circuit diagram showing a second modification of the image rejection mixer shown in FIG.

FIG. 13 is a block diagram showing a configuration of a conventional transmission circuit.

FIG. 14 is a block diagram showing a configuration of an image rejection mixer.

FIG. 15 is a circuit diagram showing a specific configuration of a conventional image rejection mixer using a polyphase filter.

FIG. 16 is an explanatory diagram showing an image signal generated in the mixer circuit.

FIG. 17 is a circuit diagram showing a conventional circuit example in which an amplifier is inserted in an intermediate stage of a polyphase filter having a two-stage configuration.

[Explanation of symbols]

S _IF ... IF (intermediate frequency) signal, _SIM ... Image signal,
S _LO ... local transmission signal (local (LO) signal), S _RF ...
RF (radio frequency) signal, 1 ... Image rejection mixer, 2, 3 ... Built-in LPF (low-pass filter),
4 ... Modulator, 5 ... Local oscillator, 6 ... PA (power amplifier), 11 ... First 90 ° phaser, 12 ... Second 90 °
Phaser, 13 ... 1st mixer circuit, 14 ... 2nd mixer circuit, 15 ... Adder, 21, 22, 31, 32 ... Polyphase filter, 15 ... Adder.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hidetoshi Tsubota             3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture               RF Chips Technology Co., Ltd.             Inside the company F term (reference) 5J098 AA02 AA11 AA14 AB03 AD29                       DA04 DA08

Claims (10)

[Claims] 1. An active polyphase filter / amplifier comprising a two-stage polyphase filter and a differential amplifier provided at a signal input stage and integrated with the polyphase filter. . 2. Further, one of the polyphase filters
Inserted between the circuit part of the second stage and the circuit part of the second stage,
The active polyphase filter amplifier according to claim 1, further comprising a grounded base amplifier integrated with the polyphase filter. 3. The active polyphase filter amplifier according to claim 1, further comprising a power feeding resistor connected to the output terminal side of the polyphase filter. 4. A mixer circuit applied to an image rejection mixer, wherein a common-emitter differential amplifier connected to a phase shifter in the image-rejection mixer and a common-emitter differential amplifier constitute a Gilbert mixer. A mixer circuit comprising: a mixer cell; and a grounded differential amplifier and a base grounded differential amplifier inserted between the mixer cell and the mixer cell. 5. A first phaser having a two-stage first polyphase filter for dividing an input signal into first and second input signals having mutually different phases, and outputting the first phaser and two stages A second phase shifter which has a second polyphase filter having a configuration and which divides an input local oscillation signal into first and second local oscillation signals having mutually different phases, and outputs the first local oscillation signal; A first mixer circuit that mixes a local oscillator signal and the first input signal; a second mixer circuit that mixes the second local oscillator signal and the second input signal; A connection of each circuit element that forms the first stage circuit of the first polyphase filter, and an adder that adds the respective output signals from the second mixer circuit and outputs a signal of a desired frequency State and one of the second polyphase filters The connection state of each circuit element forming the second circuit has a mirror image relationship with each other, and the connection state of each circuit element forming the second-stage circuit of the first polyphase filter and the second The image rejection mixer, wherein the connection state of each circuit element forming the second-stage circuit of the polyphase filter is in a mirror image relationship with each other. 6. The first phaser further comprises a differential amplifier integrated with the first polyphase filter at a signal input stage, and the second phaser further comprises a signal 6. The image rejection mixer according to claim 5, further comprising a differential amplifier integrated with the second polyphase filter in the input stage of the. 7. The first phaser further comprises:
A common ground amplifier integrated between the first polyphase filter and the first polyphase filter, the second phaser being provided between the first polyphase filter and the second polyphase filter. Further has a common-base amplifier that is inserted between the first-stage circuit portion and the second-stage circuit portion of the second polyphase filter and is integrated with the second polyphase filter. An image rejection mixer according to claim 6. 8. A first phaser for dividing an input signal into first and second input signals having mutually different phases and outputting the first and second input signals, and first and second local oscillator signals having mutually different phases. A second phase shifter for dividing and outputting the two local oscillation signals; a first mixer circuit for mixing the first local oscillation signal and the first input signal; and a second local oscillation signal And a second mixer circuit for mixing the second input signal with each other, and an adder for adding output signals from the first and second mixer circuits and outputting a signal of a desired frequency. The first and second mixer circuits respectively include a grounded-emitter differential amplifier, a mixer cell that forms a Gilbert mixer together with the grounded-emitter differential amplifier, the grounded-emitter differential amplifier, and the mixer.・ With cells Image rejection mixer, characterized in that it comprises a differential amplifier of the inserted base grounded. 9. The first phaser has a two-stage first polyphase filter, and the second phaser has a two-stage second polyphase filter, The connection state of each circuit element forming the first-stage circuit of the first polyphase filter and the connection state of each circuit element forming the first-stage circuit of the second polyphase filter are mirror images of each other. And the connection state of each circuit element forming the second-stage circuit of the first polyphase filter and the connection state of each circuit element forming the second-stage circuit of the second polyphase filter. 9. The image rejection mixer according to claim 8, wherein the connection state and the connection state are mirror images of each other. 10. A first phaser having a two-stage first polyphase filter, which divides an input signal into first and second input signals having mutually different phases and outputs the first phaser, and two stages. A second phase shifter which has a second polyphase filter having a configuration and which divides an input local oscillation signal into first and second local oscillation signals having mutually different phases, and outputs the first local oscillation signal; A first mixer circuit that mixes a local oscillator signal and the first input signal; a second mixer circuit that mixes the second local oscillator signal and the second input signal; An adder for adding respective output signals from the second mixer circuit and outputting a signal of a desired frequency, the first stage of the first and second polyphase filters,
The second-stage circuit includes a plurality of input / output lines each having a signal input terminal and a signal output terminal at both ends, a plurality of resistance elements arranged on the plurality of input / output lines, and the adjacent input / output terminals. A plurality of capacitive elements that are arranged between the lines and have one end connected to the input end of one input / output line and the other end connected to the output end of the other input / output line; The connection state of both ends of each capacitance element in the polyphase filter and the corresponding connection state of both ends of each capacitance element in the second polyphase filter are opposite to each other on the input / output line. An image rejection mixer, characterized in that it is configured as in.