JP2001313530A - Mixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixer where power of an LO signal required to turn on/off a nonlinear element can be reduced. SOLUTION: A transformer 2 boosting an LO signal is provided to a pre-stage of an anti-parallel diode pair 3 to boost the voltage of the LO signal applied to the anti-parallel diode pair 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in a transmission / reception apparatus of a wireless communication system. In particular, the present invention not only converts the frequency of a high-frequency signal but also frequently uses a GMSK (Gaussian Minimizer) often used in recent digital wireless communication systems.
um Frequency Shift Keying), QPSK (Quadrature P
hase Shift Keying), QAM (Quadrature Amplitude M
The present invention relates to a mixer used for a quadrature modulator or a quadrature demodulator using a modulation method such as odulation.

[0002]

2. Description of the Related Art For example, "Harmonic Mixing with an Antiparallel"
Diode Pair ”(COHN et al., IEEE Trans. On Microwav
e theory and techniques, Vol. MTT-23, N
o. 8, page 667 to page 673, August 1975) using an even harmonic mixer using an anti-parallel diode pair (APDP).

FIG. 10 is a circuit diagram showing a configuration of an even harmonic mixer which is a conventional mixer. In the figure, 1 is RF
(Radio Frequency) A high-pass filter (HPF) 11 connected to an RF terminal transmitting a signal, LO (Local Osci
llation) A band-pass filter (BPF) 12 and an IF connected to a LO terminal that transmits a signal (local oscillation signal)
(Intermediate Frequency) having a low-pass filter (LPF) 13 connected to an IF terminal that transmits a signal;
A demultiplexing circuit multiplexes the F signal, the LO signal, and the IF signal into a multiplexed signal or separates the multiplexed signal from the multiplexed signal. Reference numeral 3 denotes an APDP in which mixer diodes 21 and 22 are connected in opposite directions.

Next, the operation will be described. Such a conventional mixer is used as a reception mixer or a transmission mixer.

[0005] In the receiving mixer, A
The RF signal and the LO signal are applied to the PDP 3, and an IF signal that is a part of the mixed wave is extracted. In this case, the RF signal is an input signal, and the IF signal is an output signal.

When an RF signal is applied to the RF terminal, HP
Applied to APDP3 via F11. At this time, R
Leakage of the F signal to the LO terminal is prevented by the BPF 12, and leakage of the RF signal to the IF terminal is prevented by the LPF 13.

When the LO signal is applied to the LO terminal, it is applied to the APDP 3 via the BPF 12. At this time, the leakage of the LO signal to the RF terminal is prevented by the HPF 11, and the leakage of the LO signal to the IF terminal is prevented by the LPF 13.

Then, the applied R is applied by APDP3.
The F signal and the LO signal are mixed to generate a mixed wave including the IF signal, of which the IF signal is output to the IF terminal via the LPF 13 as an output signal.

On the other hand, in the transmission mixer, the IF signal and the LO signal are applied to the APDP 3 via the branching circuit 1, and the RF signal which is a part of the mixed wave is extracted. in this case,
The IF signal is an input signal, and the RF signal is an output signal.

When an IF signal is applied to the IF terminal, LP
Applied to APDP3 via F13. At this time, I
Leakage of the F signal to the LO terminal is prevented by the BPF 12, and leakage of the IF signal to the RF terminal is prevented by the HPF 11.

When the LO signal is applied to the LO terminal, it is applied to the APDP 3 via the BPF 12. At this time, the leakage of the LO signal to the RF terminal is prevented by the HPF 11, and the leakage of the LO signal to the IF terminal is prevented by the LPF 13.

The IDP applied by APDP3 is
The F signal and the LO signal are mixed to generate a mixed wave including an RF signal, and the RF signal is output to the RF terminal via the HPF 11 as an output signal.

FIG. 11 shows an AP constituting an even harmonic mixer.
FIG. 6 is a diagram illustrating an example of a relationship between a voltage and a current of DP3. Since the mixer diodes 21 and 22 are connected in parallel with opposite polarities, a current flows through the mixer diode 21 when the applied voltage is negative, and a current flows through the mixer diode 22 when the applied voltage is positive. . Mixer diode 2
The forward current I flowing in the first and second 22 is generally expressed by the following equation.

(Equation 1) Here, Is is a saturation current, q is a charge, V is an applied voltage, k is a Boltzmann constant, and T is an absolute temperature.

In the voltage-current characteristic represented by the equation (1),
When the absolute value of the applied voltage is equal to or less than the predetermined value Vt, almost no current flows, and when the absolute value of the applied voltage exceeds the predetermined value Vt, the current increases. As shown in FIG.
It can be approximated that a current flows only in a region where the applied voltage V exceeds a predetermined value Vt, or in a region where the applied voltage V is lower than a predetermined value -Vt.

FIG. 12 is a diagram showing an example of a waveform of a voltage applied to the APDP 3 and a waveform of a conducting current. As shown in FIG. 12, when the LO signal having the amplitude Vp is applied to the APDP 3, a current flows only when the voltage of the LO signal exceeds a predetermined value ± Vt.

That is, when the LO signal is applied to the even harmonic mixer, the mixer diodes 21 and 22 are provided every half cycle.
Turn on alternately, and current flows. FIG. 13 is a diagram illustrating an example of a current that conducts through the APDP 3 when the LO signal is applied.

Therefore, the conductance g of the APDP3 expressed by the following equation increases every half cycle. g = | dI / dV | (2) FIG. 14 is a diagram showing a change in the conductance of the APDP3 in the case of FIG.

Therefore, when the frequency of the RF signal is frf, the frequency of the IF signal is fif, and the frequency of the LO signal is fp, the increase in conductance occurs at a half of the cycle of the LO signal. As a result, the level of a mixed wave of a signal having a frequency twice as high as the frequency of the LO signal and the input signal increases as shown in the following equation. frf = fif ± 2fp (3)

FIG. 15 is a diagram showing an example of the frequency spectrum of each signal in an even harmonic mixer serving as a transmission mixer that inputs an LO signal and an IF signal and outputs an RF signal. As shown in FIG. 15, a mixed wave of a signal having twice the frequency of the LO signal, an RF signal and an IF signal is output. Of these, the frequency is close to the RF signal,
A signal having twice the frequency of the LO signal that becomes a spurious is suppressed. The amount of suppression at this time depends on the identity of the characteristics of the two mixer diodes 21 and 22 and does not depend on an external circuit such as the branching circuit 1. Therefore, even-order harmonics of the LO signal are largely suppressed by monolithically integrating the two mixer diodes 21 and 22 and forming them uniformly. As a result, in the even harmonic mixer, unnecessary waves can be largely suppressed as compared with a normal balanced mixer in which unnecessary waves are suppressed by the balance of an external circuit. For example, in the case of a microwave, the amount of suppression in the case of a balanced mixer is about 25 dB in a mixer that operates with a normal fundamental wave, but it is possible to suppress 50 dB to 60 dB in an even harmonic mixer.

Further, as shown in the equation (3), the even harmonic mixer can be operated with a LO signal having a frequency approximately half of that of the RF signal. Therefore, even in the above-mentioned documents and many other documents, the even harmonic mixer is applied to a microwave or millimeter wave transceiver.

[0021]

Since the conventional mixer is configured as described above, a non-linear element such as a mixer diode is turned on / off based on the LO signal.
There were problems such as an increase in the power required for the O signal.

That is, the required power of the LO signal is a predetermined value Vt of the voltage-current characteristic of the mixer diodes 21 and 22.
Is determined by For example, the predetermined value Vt is about 0.7 V for a gallium-arsenic Schottky barrier diode often used in microwaves, and the predetermined value Vt is 0.3 V to 0.6 V for a silicon Schottky barrier diode.
It is about. The effective voltage Vrms [V] of the LO signal is L
If the O signal is a sine wave, it is obtained by the following equation. Vrms = Vp / √2 (4) This effective voltage Vrms [V] is converted into the impedance Zo.
The power P [W] required to realize the [Ω] system is obtained by the following equation. P = Vrms ² / Zo (5)

Therefore, the mixer diodes 21 and 22
Assuming that the impedance Zo of the system at the time of applying the signal wave to the normal microwave circuit is 50Ω, in order to set the amplitude Vp of the LO signal to 0.7 V, 4.9 mW ≒ 7d
When the power P of Bm is required for the LO signal and the amplitude Vp of the LO signal is set to 0.3 V, 0.9 mW ≒ 0 dBm
Is required for the LO signal. For this reason, the required power of the mixer using the diode is larger than the general required power of the mixer using the transistor or the FET (Field Effect Transistor) of about −10 dBm.

For this reason, in the conventional mixer, it is necessary to provide an amplifier for the LO signal before the LO terminal, and the power consumption is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. A transformer for boosting an LO signal or a circuit for converting the impedance of the LO signal is provided in a stage preceding the nonlinear element. It is an object of the present invention to obtain a mixer capable of reducing signal power.

[0026]

A mixer according to the present invention is applied with a transformer for boosting a local oscillation signal, a local oscillation signal boosted by the transformer and an input signal, and generates a mixed wave thereof. And a non-linear element.

The mixer according to the present invention is provided with a demultiplexer circuit connected to the transformer and for demultiplexing the input signal, the local oscillation signal, and the output signal from the mixed wave.

In the mixer according to the present invention, the nonlinear element is an anti-parallel diode pair.

A mixer according to the present invention includes a negative-phase distribution circuit that distributes a local oscillation signal in a reverse phase and applies the same to a transformer, applies an input signal to a nonlinear element, and outputs an output signal in a phase opposite to the input signal. And a reverse-phase synthesizer.

The mixer according to the present invention includes a nonlinear element,
This is four mixer diodes connected in a ring.

In the mixer according to the present invention, the nonlinear element is a transistor or an FET.

A mixer according to the present invention is provided with an impedance conversion circuit which receives a local oscillation signal and makes the output terminal impedance higher than the input terminal impedance, and a local oscillation signal and an input signal which are output by the impedance conversion circuit. And a non-linear element that generates a mixed wave thereof.

In the mixer according to the present invention, the impedance conversion circuit is a low-pass filter or a high-pass filter.

The mixer according to the present invention includes a nonlinear element for generating a mixed wave of an input signal and a local oscillation signal, and a terminal impedance on the nonlinear element side relative to the input terminal impedance of the local oscillation signal. And a demultiplexing circuit for demultiplexing the input signal, the local oscillation signal, and the output signal from the mixed wave.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a circuit diagram showing a configuration of a mixer according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing a transformer 2 in FIG. 1 and 2, reference numeral 1 denotes a high-pass filter (HPF) 11 connected to an RF terminal transmitting an RF signal, a band-pass filter (BPF) 12 connected to an LO terminal transmitting an LO signal, and an IF signal. A low-pass filter (LPF) 13 connected to an IF terminal that transmits the RF signal, the LO signal, and the IF signal.
A demultiplexing circuit for multiplexing a signal into a multiplexed signal or demultiplexing the multiplexed signal from the multiplexed signal;
The transformation ratio between the branching circuit 1 side and the APDP3 side is 1: N (N>
A transformer 1), and an anti-parallel diode pair (APDP) 3 in which mixer diodes 21 and 22 are connected in opposite directions.

Next, the operation will be described. The mixer according to the first embodiment is used as a reception mixer or a transmission mixer.

In the receiving mixer, the RF signal and the LO signal are applied to the APDP 3 via the branching circuit 1 and the transformer 2, and the IF signal which is a part of the mixed wave is extracted. In this case, the RF signal is an input signal, and the IF signal is an output signal.

When an RF signal is applied to the RF terminal, HP
Applied to the transformer 2 via F11. At this time, RF
Leakage of the signal to the LO terminal is prevented by the BPF 12,
Leakage of the RF signal to the IF terminal is prevented by the LPF 13.

When the LO signal is applied to the LO terminal, it is applied to the transformer 2 via the BPF 12. At this time, the leakage of the LO signal to the RF terminal is prevented by the HPF 11, and the leakage of the LO signal to the IF terminal is prevented by the LPF 13.

The voltage of these signals is boosted N times by the transformer 2, and the boosted signal is applied to the APDP 3. At this time, the output impedance of the branching circuit 1 is Zo, the power of the LO signal input to the transformer 2 is Plo_in, as shown in FIG.
The voltage of the signal is Vlo_in, and L
Assuming that the voltage of the O signal is Vlo_out, the voltage Vlo_out of the LO signal on the output side is N times the voltage Vlo_in of the LO signal on the input side, as shown in the following equation. Vlo_out = N · Vlo_in = N · (Plo_in · Zo) ^1/2 (6)

For example, if the output impedance Zo of the branching circuit 1 is 50Ω and the transformation ratio N in the transformer 2 is 2, if the power Plo_in of the LO signal to the transformer 2 is 1 dBm, for example, LO signal voltage Vl
o_in is about 0.35V, and the voltage Vlo_out of the LO signal on the output side is about 0.71V. Therefore,
When the output impedance Zo of the demultiplexing circuit 1 is 50Ω, power of about 1 dBm is sufficient to make the amplitude Vp of the LO signal applied to the mixer diodes 21 and 22 to 0.7V. That is, the power is reduced to １ ／ of the power (= 7 dBm) required in the similar case in the above-described conventional mixer.

When the LO signal and the RF signal boosted by the transformer 2 are applied to the APDP 3, the AP
DP3 mixes the LO signal and the RF signal to form I
A mixed wave including the F signal is generated, and the mixed wave is
Is reduced to 1 / N by IF, and IF of the mixed wave after the
The signal is output to the IF terminal via the LPF 13 as an output signal.

On the other hand, in the transmission mixer, the IF signal and the LO signal are applied to the APDP 3 via the branching circuit 1 and the transformer 2, and the RF signal which is a part of the mixed wave is extracted. In this case, the IF signal is an input signal and the RF signal is an output signal.

When an IF signal is applied to the IF terminal, LP
It is applied to the transformer 2 via F13. At this time,
Leakage of the signal to the LO terminal is prevented by the BPF 12,
Leakage of the IF signal to the RF terminal is prevented by the HPF 11.

When the LO signal is applied to the LO terminal, it is applied to the transformer 2 via the BPF 12. At this time, the leakage of the LO signal to the RF terminal is prevented by the HPF 11, and the leakage of the LO signal to the IF terminal is prevented by the LPF 13.

The voltage of these signals is boosted N times by the transformer 2 and the boosted signal is applied to the APDP 3. When the LO signal and the IF signal boosted by the transformer 2 are applied to the APDP 3, the LO signal and the IF signal are mixed by the APDP 3 to generate a mixed wave including an RF signal. , The RF signal of the mixed wave after the voltage drop is output to the RF terminal as an output signal via the HPF 11.

As described above, according to the first embodiment, the LO signal is boosted by the transformer 2 and the boosted LO signal is applied to the non-linear elements such as the mixer diodes 21 and 22 together with the input signal. Therefore, the effect that the power of the LO signal applied to the mixer can be reduced can be obtained. Therefore, it is not necessary to provide an amplifier for amplifying the LO signal before the mixer.

FIG. 3 is a circuit diagram showing another configuration of the mixer according to the first embodiment of the present invention. In FIG. 1, HPF 11, BPF 12, and LP
The multiplexed signal to be split / combined using F13 is
And BPF, as shown in FIG.
A similar effect can be obtained even if only the LO signal from 12 passes through the transformer 2.

As another configuration of the mixer according to the first embodiment of the present invention, a fundamental wave mixer using a diode may be used. FIG. 4 is a circuit diagram showing a configuration of a fundamental wave mixer as another configuration of the mixer according to the first embodiment of the present invention. In the figure, 31 is connected to the LO terminal,
A reverse-phase distribution circuit that distributes the O signal in reverse phase, and 32 is an RF
Ring-shaped mixer diodes 41 to 4 connected to terminals
RF generated by mixing LO signal and IF signal
A negative-phase combiner for combining / separating the signal and the IF signal in opposite phases; 41 to 44 are four mixer diodes as non-linear elements connected in a ring shape in the same circling direction; It is a transformer provided between the mixer diodes 41 to 44 and the negative-phase distribution circuit 31.

With this configuration, similarly,
The amplitude of the LO signal applied to the mixer diodes 41 to 44 is increased, and an effect is obtained that the fundamental wave mixer can be operated with low power.

Further, as another configuration of the mixer according to the first embodiment of the present invention, a transistor or FET may be used as a non-linear element instead of the above-described mixer diode. FIG. 5 is a circuit diagram showing a configuration of a mixer using FETs as another configuration of the mixer according to the first embodiment of the present invention. In the figure, reference numeral 51 denotes a dual gate FET as a non-linear element, 52 denotes one gate terminal of the dual gate FET 51 connected to the transformer 2, and 53 denotes the other gate of the dual gate FET 51 connected to the IF terminal. 54 is an RF terminal
A drain terminal of the dual gate FET 51 connected to the terminal, 55 is a grounded dual gate FET 5
1 is a source terminal. 2 is a LO terminal and a gate terminal 52
And a transformer provided between them.

In the mixer having this configuration, when the IF signal is applied to the gate terminal 53 and the boosted LO signal is applied to the gate terminal 52, the L signal is applied from the drain terminal 54 to the RF terminal.
An RF signal that is a mixed wave of the O signal and the IF signal is output.

With this configuration, similarly,
Since the LO signal applied to the dual-gate FET 51 is boosted, the effect of reducing the power of the LO signal applied to the LO terminal can be obtained even in a mixer using a transistor or FET as a non-linear element.

Although the single mixer has been described in the first embodiment, the present invention can be applied to two mixers and a quadrature mixer having a LO wave distributor and an RF signal combiner. The power of the LO signal to be applied can be reduced.

Although a single mixer has been described in the first embodiment, the present invention relates to an image rejection mixer having two mixers and a LO wave distributor, an RF signal combiner, and an IF signal distributor. And the power of the LO signal applied to the image rejection mixer can be reduced.

Embodiment 2 FIG. 6 is a circuit diagram showing a configuration of a mixer according to Embodiment 2 of the present invention. In the figure, 61 is provided between the demultiplexing circuit 1 and the APDP 3,
This is an LPF (impedance conversion circuit) in which the terminal impedance on the APDP3 side is higher than the terminal impedance on the branching circuit 1 side. The other components in FIG. 6 are the same as those according to the first embodiment, and a description thereof will not be repeated.

Next, the operation will be described. FIG. 7 is a diagram showing an example of the pass characteristic of the LPF 61 in FIG. In the mixer according to the second embodiment, the LO signal is applied to the APDP 3 via the LPF 61 having the terminal impedance on the APDP 3 side higher than the terminal impedance on the branching circuit 1 side. At this time, the terminal impedance as viewed from the APDP3 is increased by the LPF 61, and based on the equation (5), a LO signal having a larger amplitude Vp is applied to the APDP3 with the same LO signal power Plo_in.

Further, in the mixer diodes 21 and 22, not only the second harmonic of the LO signal but also higher-order spurs such as the third harmonic and the fourth harmonic are generated, but as shown in FIG. If the cutoff frequency is set slightly higher than the frequency of the RF signal, the LPF 61 attenuates higher-order spurious.

As described above, according to the second embodiment, the impedance conversion is performed by the LPF 61,
Since the LO signal that has passed through the LPF 61 is applied to the non-linear elements such as the mixer diodes 21 and 22 together with the input signal, the power of the LO signal applied to the mixer can be reduced.

According to the second embodiment, the LPF
Since the cutoff frequency of the RF signal 61 is set to be slightly higher than the frequency of the RF signal, high-order spurious generated in the mixer diodes 21 and 22 is attenuated, and the RF terminal and the LO
The effect that unnecessary waves leaking to the terminal and the IF terminal can be suppressed can be obtained.

In FIG. 6, H is used as the branching circuit 1.
A multiplexed signal that is split / combined using the PF11, the BPF12, and the LPF13 is transmitted to and received from the LPF61. For example, assuming that the transformer 2 in FIG. Only signal is L
Similar effects can be obtained by passing through the PF 61.

As another configuration of the mixer according to the second embodiment of the present invention, for example, the transformer 2 in FIG.
A fundamental wave mixer using a diode instead of the PF61 may be used. With such a configuration, similarly, the amplitude of the LO signal applied to the mixer diodes 41 to 44 is increased, and an effect is obtained that the fundamental wave mixer can be operated with low power.

Further, as another configuration of the mixer according to the second embodiment of the present invention, for example, the transformer 2 in FIG. 5 is changed to an LPF 61. Instead of the above-described mixer diode, a transistor or FET is used as a non-linear element. It may be. With such a configuration, similarly, even in a mixer using a transistor or FET as a non-linear element, the effect of reducing the power of the LO signal applied to the LO terminal can be obtained.

Although the single mixer has been described in the second embodiment, the present invention can be applied to two mixers and a quadrature mixer having a LO wave distributor and an RF signal combiner. The power of the LO signal to be applied can be reduced.

Although a single mixer has been described in the second embodiment, the present invention relates to an image rejection mixer having two mixers and a LO wave distributor, an RF signal combiner, and an IF signal distributor. And the power of the LO signal applied to the image rejection mixer can be reduced.

Embodiment 3 FIG. 8 is a circuit diagram showing a configuration of a mixer according to Embodiment 3 of the present invention. In the figure, 71 is provided between the demultiplexing circuit 1 and the APDP 3,
This is an HPF (impedance conversion circuit) in which the terminal impedance on the APDP3 side is higher than the terminal impedance on the branching circuit 1 side. Note that the other components in FIG. 8 are the same as those in the first embodiment, and a description thereof will not be repeated.

Next, the operation will be described. In the mixer according to the third embodiment, the terminal impedance on the APDP3 side is higher than the terminal impedance on the
The LO signal is applied to APDP3 via F71. At this time, the terminal impedance as viewed from the APDP3 is converted by the HPF 71, and based on the equation (5), the LO signal having the same LO signal power Plo_in and the larger amplitude Vp is applied to the APDP3.

Further, by setting the cutoff frequency of the HPF 71 to be slightly lower than the frequency of the IF signal, a spurious component having a low frequency is attenuated.

As described above, according to the third embodiment, the impedance conversion is executed by the HPF 71,
Since the LO signal that has passed through the HPF 71 is applied to the non-linear elements such as the mixer diodes 21 and 22 together with the input signal, the effect of reducing the power of the LO signal applied to the mixer can be obtained.

According to the third embodiment, the HPF
Since the cut-off frequency of the IF signal 71 is set slightly lower than the frequency of the IF signal, spurious low frequencies generated in the mixer diodes 21 and 22 are attenuated, and unnecessary waves leaking to the RF terminal, LO terminal and IF terminal are reduced. The effect of being able to suppress is obtained.

In FIG. 8, H is used as the branching circuit 1.
A multiplexed signal to be demultiplexed / combined using the PF11, the BPF12 and the LPF13 is exchanged with the HPF 71. For example, assuming that the transformer 2 in FIG. Only signal is H
Similar effects can be obtained by passing through the PF 71.

As another configuration of the mixer according to the third embodiment of the present invention, for example, the transformer 2 in FIG.
A fundamental wave mixer using a diode instead of the PF 71 may be used. With such a configuration, similarly, the amplitude of the LO signal applied to the mixer diodes 41 to 44 is increased, and an effect is obtained that the fundamental wave mixer can be operated with low power.

Further, as another configuration of the mixer according to the third embodiment of the present invention, for example, the transformer 2 in FIG. 5 is changed to an HPF 71, and a transistor or FET is used as a non-linear element instead of the above-described mixer diode. It may be. With such a configuration, similarly, even in a mixer using a transistor or FET as a non-linear element, the effect of reducing the power of the LO signal applied to the LO terminal can be obtained.

Although the single mixer has been described in the third embodiment, the present invention can be applied to two mixers and a quadrature mixer having a LO wave distributor and an RF signal combiner. The power of the LO signal to be applied can be reduced.

Although a single mixer has been described in the third embodiment, the present invention relates to an image rejection mixer having two mixers and a LO wave distributor, an RF signal combiner, and an IF signal distributor. And the power of the LO signal applied to the image rejection mixer can be reduced.

Embodiment 4 FIG. 9 is a circuit diagram showing a configuration of a mixer according to Embodiment 4 of the present invention. In the figure, reference numeral 12A denotes a BPF (impedance conversion circuit) that transmits a LO signal connected to the LO terminal and has a terminal impedance on the APDP3 side higher than that on the LO terminal side. The other components in FIG. 9 are the same as those in the first embodiment,
The description is omitted.

Next, the operation will be described. The LO signal passing through the BPF 12A of the demultiplexer 1 is applied to the APDP3. At this time, the terminal impedance as viewed from the APDP 3 is increased by the BPF 12A, and based on Equation (5), a LO signal having a larger amplitude Vp is applied to the APDP 3 with the same LO signal power Plo_in.

In the case of a reception mixer, an RF signal passing through the HPF 11 is applied to the APDP 3, and an IF signal which is a part of a mixed wave passes through the LPF 13 and is output. In the case of a transmission mixer, the RF signal passes through the LPF 13. IF signal is AP
The RF signal applied to DP3 and being part of the mixed wave is HP
It is output after passing through F11.

The HPF 1 for demultiplexing the RF signal
APDP3 of LPF13 for demultiplexing 1 and IF signals
If the terminal impedance on the side is set to 50Ω in a normal microwave circuit in each pass band, the branching circuit 3 operates with no particular problem with respect to the microwave.

As described above, according to the fourth embodiment, the BPF 1 that transmits the LO signal connected to the LO terminal
2A, the terminal impedance on the APDP 3 side is higher than the terminal impedance on the LO terminal side, so that the effect of reducing the power of the LO signal applied to the mixer can be obtained.

As another configuration of the mixer according to the fourth embodiment of the present invention, a fundamental wave mixer using a diode may be used. In that case, the same effect can be obtained.

Further, as another configuration of the mixer according to the fourth embodiment of the present invention, a transistor or FET may be used as a nonlinear element instead of the above-described mixer diode. In that case, the same effect can be obtained.

Although a single mixer has been described in the fourth embodiment, the present invention can be applied to two mixers and a quadrature mixer having a LO wave distributor and an RF signal combiner. The power of the LO signal to be applied can be reduced.

Although the single mixer has been described in the fourth embodiment, the present invention relates to an image rejection mixer having two mixers and a LO wave distributor, an RF signal combiner and an IF signal distributor. And the power of the LO signal applied to the image rejection mixer can be reduced.

[0085]

As described above, according to the present invention, the transformer for boosting the local oscillation signal, the local oscillation signal boosted by the transformer and the input signal are applied to generate a mixed wave thereof. And a non-linear element
There is an effect that the power of the LO signal applied to the mixer can be reduced.

According to the present invention, the demultiplexing circuit connected to the transformer for demultiplexing the input signal, the local oscillation signal, and the output signal from the mixed wave is provided, and the non-linear element is an anti-parallel diode pair. There is an effect that an even harmonic mixer operating with a power LO signal can be realized.

According to the present invention, a negative-phase distribution circuit for distributing a local oscillation signal in a reverse phase and applying the same to a transformer, applying an input signal to a nonlinear element, and outputting an output signal in a phase opposite to the input signal. Since there is provided an anti-phase combiner and the nonlinear elements are four mixer diodes connected in a ring, there is an effect that a fundamental wave mixer operating with a low-power LO signal can be realized.

According to the present invention, since the non-linear element is a transistor or an FET, there is an effect that a transistor mixer or an FET mixer operating with a low-power LO signal can be realized.

According to this invention, the local oscillation signal is input, and the impedance conversion circuit for making the output terminal impedance higher than the input terminal impedance, and the local oscillation signal and the input signal output by the impedance conversion circuit are separated. And a non-linear element that generates a mixed wave of these signals.
There is an effect that the power of the signal can be reduced.

According to the present invention, since the impedance conversion circuit is a low-pass filter or a high-pass filter, the spurious generated by the nonlinear element is attenuated,
There is an effect that unnecessary waves leaking to the terminal, the LO terminal, and the IF terminal can be suppressed.

The mixer according to the present invention is connected to a nonlinear element for generating a mixed wave of an input signal and a local oscillation signal, and to a terminal impedance on the nonlinear element side of the local oscillation signal with respect to the terminal impedance on the input side for the local oscillation signal. And a demultiplexing circuit for demultiplexing the input signal, the local oscillation signal, and the output signal from the mixed wave.
There is an effect that the power of the LO signal applied to the mixer can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a mixer according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a transformer in FIG. 1;

FIG. 3 is a circuit diagram showing another configuration of the mixer according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a fundamental wave mixer as another configuration of the mixer according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a configuration of a mixer using an FET as another configuration of the mixer according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing a configuration of a mixer according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a pass characteristic of the LPF in FIG. 6;

FIG. 8 is a circuit diagram showing a configuration of a mixer according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a mixer according to a fourth embodiment of the present invention.

FIG. 10 is a circuit diagram showing a configuration of an even harmonic mixer which is a conventional mixer.

FIG. 11 is a diagram illustrating an example of a relationship between a voltage and a current of an APDP forming an even harmonic mixer.

FIG. 12 is a diagram showing an example of a waveform of a voltage applied to an APDP and a waveform of a conducting current.

FIG. 13 is a diagram illustrating an example of a current that conducts through the APDP when an LO signal is applied.

FIG. 14 is a diagram showing a change in the conductance of APDP in the case of FIG.

FIG. 15 is a diagram illustrating an example of a frequency spectrum of each signal in an even harmonic mixer serving as a transmission mixer that inputs a LO signal and an IF signal and outputs an RF signal.

[Explanation of symbols]

1 branching circuit, 2 transformers, 12A BPF (impedance conversion circuit), 21, 22, 41 to 44 mixer diode (non-linear element), 31 reverse phase distribution circuit, 32
Negative phase synthesizer, 51 Dual gate FET (non-linear element), 61 LPF (impedance conversion circuit), 71
HPF (impedance conversion circuit).

Claims (9)

[Claims] 1. A mixer for mixing an input signal and a local oscillation signal and outputting a predetermined frequency component of a mixed wave as an output signal, wherein: a transformer for boosting the local oscillation signal; And a non-linear element to which the local oscillation signal and the input signal are applied and generate a mixed wave thereof. 2. The mixer according to claim 1, further comprising a branching circuit connected to the transformer and branching an input signal, a local oscillation signal, and an output signal from the mixed wave. 3. The mixer according to claim 2, wherein the non-linear element is an anti-parallel diode pair. 4. A negative-phase distribution circuit for distributing a local oscillation signal in a reverse phase and applying the same to a transformer, and a reverse-phase combining circuit for applying an input signal to a non-linear element and outputting an output signal in a phase opposite to the input signal. The mixer according to claim 1, further comprising a container. 5. The non-linear element includes four ring-shaped elements.
5. The number of mixer diodes.
The mixer described. 6. The non-linear element is a transistor or an FE.
The mixer according to claim 1, wherein T is T. 7. A mixer that mixes an input signal and a local oscillation signal and outputs a predetermined frequency component of a mixed wave as an output signal, wherein the local oscillation signal is input, and an output terminal is connected to a terminal impedance on an input side. And a non-linear element to which a local oscillation signal output from the impedance conversion circuit and the input signal are applied to generate a mixed wave thereof. 8. The mixer according to claim 7, wherein the impedance conversion circuit is a low-pass filter or a high-pass filter. 9. A mixer that mixes an input signal and a local oscillation signal and outputs a predetermined frequency component of the mixed wave as an output signal, wherein the mixer includes a nonlinear element that generates a mixed wave of the input signal and the local oscillation signal. , Connected to the nonlinear element, the terminal impedance on the nonlinear element side is higher than the terminal impedance on the input side for the local oscillation signal, and the input signal, the local oscillation signal and the output signal from the mixed wave A mixer, comprising: a demultiplexing circuit for demultiplexing.