JP2000223956A - Image cancel mixer circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with plural frequency bands by making an image cancel mixer circuit usable even when a difference is generated between conversion gains of a frequency converting circuit due to variations of elements, etc. SOLUTION: The image cancel mixer circuit is constituted by providing a 90 degree phase shift circuit 6 to output a first local oscillation signal el1 and a second local oscillation signal with a phase different from the signal by el1 by n×π×2, a frequency converting circuit 1 to convert frequency of an input signal Si by the signal el1, a frequency converting circuit 22 to similarly convert the frequency of the input signal Si by the signal el2, and a phase shift synthetic circuit 5 to adjust phases of output S1 of the frequency converting circuit 1 and output S2 of the frequency converting circuit 2 and to sum the output together. In this case, the image cancel mixer circuit is provided with an adder part 3 to add the output S1 of the frequency converting circuit 1 to the output S2 of the frequency converting circuit 2, a subtracting part 4 to subtract the output S2 from the output S1. Phases of output S3 of the adder part and output S4 of the subtracting part are adjusted and summed together by the phase shift synthetic circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image cancellation mixer circuit, and more particularly to a GSM (Global System Foam).
r Mobile Communication), EGSM (Extra System f)
or Mobile Communication), DCS (Digital Communi)
cation System) 1800, PCS (Personal Communic)
The present invention relates to an image canceling mixer circuit used for a digital communication portable communication terminal such as 1900 and a plurality of digital communication portable communication terminals such as a dual band device.

[0002]

2. Description of the Related Art In a communication circuit technology, a frequency conversion circuit is an important circuit block for improving the performance of a communication system, and is frequently used. Since the image signal becomes an image disturbance at the input stage of the frequency conversion circuit,
An interstage filter for removing an image signal is used. Image disturbance is disturbance that occurs in principle during frequency conversion. In order to reduce the inter-stage filter for removing the image, a frequency conversion circuit unit having an image signal suppression characteristic has been proposed, and this is an image cancel mixer circuit. A conventional example is disclosed in JP-A-52-132710.
There is one shown in FIG.

The operation principle of the conventional image cancel mixer circuit will be described with reference to FIGS. A conventional image canceling mixer circuit has a first frequency conversion circuit 1 as shown in FIG.
A second frequency conversion circuit 2, a 90-degree phase shift circuit 6,
The phase shift synthesizing circuit 5 is provided. The first frequency conversion circuit 1 outputs the frequency-converted signal S input from the terminal T1.
The frequency conversion is performed by multiplying i by the first local oscillation signal el1, and the signal is output as a signal S1. The second frequency conversion circuit 2 frequency-converts the frequency-converted signal Si input from the terminal T1 by multiplying the frequency-converted signal Si by the second local transmission signal el2 and outputs the signal as a signal S2.

The 90-degree phase shift circuit 6 comprises a doubler circuit 62 for doubling the frequency and a 1/2 frequency divider 61 for halving the frequency, and a basic local oscillation signal inputted from a terminal T2. Based on ωl, the first local oscillation signal el1 and the second
Is output. The first local oscillation signal el1 and the second local oscillation signal el2 have a phase of n × π
/ 2 (n = 1, 3, 5, 7,..., Π = 180 degrees).

The phase shift synthesizing circuit 5 includes a phase shifter 51 and an adder 5
Consists of two. An output S1 of the first frequency conversion circuit 1 and an output S2 of the second frequency conversion circuit 2 are input to a phase shift synthesizing circuit 5, and an output S1 of the first frequency conversion circuit 1 and a second frequency conversion circuit 2 Are adjusted by the phase shifter 51, then combined by the adder 52 and output from the terminal T3.

The principle of operation of the image cancel mixer circuit will be described with reference to the vector diagram of FIG. FIG. 7 (a)
, Ωs is a vector diagram showing a desired signal component of the signal Si in the first frequency band, ωi is a vector diagram showing an unnecessary image component mixed in the signal Si in the first frequency band, and ω1 is a vector diagram of the local oscillation signal ω1. The components are shown.

The output S1 of the first frequency conversion circuit 1 is composed of the signal ωs in the specific frequency band and the first local oscillation signal el.
The result of multiplication with the output component ωl of 1 is output. The output S1 is specifically shown below by mathematical expressions. Frequency conversion signal S
Assuming that the desired wave component es of i is es = Es × sinωs · t, the image component ei of the frequency-converted signal Si is ei = Ei × sinωi · t, and the first local oscillation signal el1 is el1 = El × sinωl · t. The frequency conversion signal Si is frequency-converted by the first local oscillation signal el1, and (es + ei) × el1 = (Es × sinωs · t + Ei × sinωi · t) × (El × sinωl · t) = (Es · El) / 2 × {cos (ω1−ωs) ・ t−cos (ω1 + ωs) ・ t} + (Ei ・ El) / 2 × {cos (ω1−ωi) ・ t−cos (ω1 + ωi) ・ t} (1) Becomes When the difference component of the multiplication is used as the intermediate frequency signal, the frequencies (ωl + ωs) and (ωl + ωi) can be excluded, and therefore, (es + ei) × el1 = ((Es · El) / 2) × cos (ωl− ωs) · t + ((Ei · El) / 2) × cos (ω1−ωi) · t = ((Es · El) / 2) × cosωifs1 · t + ((Ei · El) / 2) × cosωifi1 · t (2) ((ωl−ωs) = ωifs1, (ω1−ωi)
= Ωifi1. 7), the first desired intermediate frequency ωifs1 obtained by frequency-converting the desired signal and the first image intermediate frequency ωifi1 obtained by frequency-converting the image signal are output in phase.

On the other hand, the output S2 of the second frequency conversion circuit 2
Is the frequency conversion signal Si and the second local oscillation signal el2
(Ω1 + π / 2, when n = 1), and the frequency conversion is performed. As a result of the multiplication, if the second local oscillation signal el2 is given by el2 = El × sin (ωl · t + π / 2), (Es + ei) × el2 = (Es × sinωs · t + Ei × sinωi · t) × (El × sin (ωl · t + π / 2)) = (Es · El) / 2 × ｛sin (ω1−ωs) · t + sin (ω1 + ωs) ) · T｝ − (Ei · El) / 2 × ｛sin (ωl−ωi) · t + sin (ωl + ωi) · t)

Here, since the difference component of the multiplication is used as the intermediate frequency signal, the frequencies (ω1 + ωs) and (ω1 +
Since (ωi) can be considered excluding, (es + ei) × el2 = (Es · El) / 2 × (sin (ω1−ωs) · t) − ((Ei · El) / 2) × (sin ( ωl−ωi) · t) = ((Es · El) / 2) × cosωifs2 · t + ((Ei · El) / 2) × cosωifi2 · t (where (ω1−ωs) + π / 2 = ωifs2, ωl
−ωi) −π / 2 = ωifi2. )

Then, ωifs2 = ωifs1 + π / 2 ωifi2 = ωifi1-π / 2, and as shown in FIG. 7C, the second desired intermediate frequency signal ωifs2 obtained by frequency-converting the desired signal and the image signal undergo frequency conversion The obtained second image intermediate frequency signal ωifi2 has an opposite phase, and the first desired intermediate frequency signal ωifs1 and the image intermediate number signal ωifi1 are 9
Outputs that are 0 degrees out of phase. Here, each signal ωifs
2, ωifi2, ωifs1, ωifi1 are:
All equal.

A first desired intermediate frequency signal ωifs1 and a first image intermediate number signal ωifi1 shown in FIG.
As shown in FIG. 7D, the phase of the signal is
After π / 2, as shown in FIG. 7C, when the second desired intermediate frequency signal ωifs2 and the second image intermediate frequency signal ωifi2 are added, the first and second image signal components have opposite phases. Since the magnitudes are equal, they can cancel each other. Since the first and second desired intermediate frequency signals are in phase, only the frequency component of the desired frequency can be output as the intermediate frequency output 17.

However, in the conventional image cancellation mixer circuit shown in FIG. 6, the first frequency conversion circuit 1 and the second frequency conversion circuit 2 are usually designed so that conversion gains and the like have the same characteristics. Have been. Therefore, when there is a difference between the conversion gains of the two frequency conversion circuits due to variations in the elements constituting the circuit or the like, the operation of the image cancellation mixer circuit, as shown in FIG. There is a problem that the signal cannot be canceled and is output to the intermediate frequency output 17 including the image signal component.

At present, portable telephones are used in various systems depending on the country of use and the difference in frequency allocation. In the world, portable telephones that use a frequency band near 900 Mhz such as GSM are mainstream. Due to problems such as an increase in the number of users, systems in higher frequency bands such as 1.5 Ghz band and 1.9 Ghz band have appeared, and various communication systems have been operated. For this reason, portable telephones capable of transmitting and receiving a single signal in such a plurality of systems have appeared, and in designing a signal processing LSI corresponding to this, a plurality of frequency conversion circuits have been incorporated.

As an example, FIG. 9 shows a block diagram of an image cancellation mixer circuit (dual band image cancellation mixer) corresponding to two frequency bands. This dual-band image canceling mixer circuit has two
A first frequency conversion circuit 1-1, a second frequency conversion circuit 2-1, a third frequency conversion circuit 1-2, and a fourth frequency conversion circuit 2; -2, 90-degree phase shift circuit 6 and phase shift synthesizing circuit 5 are provided.

The first frequency conversion circuit 1 performs frequency conversion by multiplying the first frequency-converted signal Si1 input from the terminal T1 by the first local oscillation signal el1, and outputs a signal S1-1. . The second frequency conversion circuit 2 converts the first frequency-converted signal Si1 into a second local oscillation signal el.
The frequency is converted by multiplying by 2 and output as a signal S2-1.

The third frequency conversion circuit 1-2 has a terminal T4
The frequency conversion is carried out by multiplying the second frequency-converted signal Si2 inputted from the first input terminal by the first local transmission signal el1, and the resultant signal is output as a signal S1-2. The fourth frequency conversion circuit 2-2 performs frequency conversion by multiplying the second frequency-converted signal S2 by the second local transmission signal el2 and outputs the signal as a signal S2-2.

The 90-degree phase shift circuit 6 comprises a doubler circuit 62 for doubling the frequency and a 1/2 frequency divider 61 for halving the frequency, and is based on the input basic local oscillation signal ωl. Then, the first local transmission signal el1 and the second local transmission signal el2 are output. First local oscillation signal and el1 second
The phase of the local oscillation signal el2 is n × π / 2 (n =
1, 3, 5, 7,..., Π = 180 degrees).

The phase shift synthesizing circuit 5 adjusts the phase of the output of the first frequency conversion circuit 1-1 and the output of the second frequency conversion circuit 2-1 and adds them. 4, and adjusts the phase of the output of the frequency conversion circuit 2-2.

When the frequency of the input signal Si1 of the first frequency band is converted, the first frequency conversion circuit 1 and the second
Is operated, but the third frequency conversion circuit 1-2 and the fourth frequency conversion circuit 2-2 are turned off. On the other hand, when performing frequency conversion on the input Si2 of the signal in the second frequency band, the third frequency conversion circuit 1-2 and the fourth frequency conversion circuit 2-2 are operated, but the first frequency conversion circuit is operated. The first and second frequency conversion circuits 2 are turned off. Focusing on the block configuration excluding the frequency conversion circuit that is turned off, the configuration is the same as that of FIGS. 6 and 7, and the operation principle is the same as that of FIG.

As described above, the conventional dual-band image cancellation mixer circuit requires two frequency conversion circuits in one frequency band, and therefore requires a circuit size twice as large as the number of corresponding frequency bands. There was a problem that it was not suitable for conversion.

[0021]

SUMMARY OF THE INVENTION The present invention solves the problems encountered in the prior art, and can be used even if a difference occurs in the conversion gain of the frequency conversion circuit due to variations in elements or the like. An object of the present invention is to provide an image cancel mixer circuit capable of reducing an increase in circuit scale when dealing with a plurality of frequency bands.

[0022]

According to the present invention, there is provided a first local oscillation signal and a phase having a phase of n × π / 2 from the first local oscillation signal.
(N = 1, 3, 5, 7,..., Π = 180 degrees) a 90-degree phase shift circuit for outputting a second local oscillation signal shifted;
A first frequency conversion circuit that frequency-converts the frequency-converted signal with the first local oscillation signal, a second frequency conversion circuit that frequency-converts the frequency-converted signal with the second local oscillation signal, A phase-shift synthesizing circuit that adjusts the phase of the output of the first frequency conversion circuit and the output of the second frequency conversion circuit and adds the two, and the output of the first frequency conversion circuit An adder for adding the output of the second frequency converter; and a subtractor for subtracting the output of the second frequency converter from the output of the first frequency converter. The circuit is an image cancel mixer circuit that adjusts the phase of the output of the adder and the output of the subtractor and adds the images.

Further, according to the present invention, when the frequency allocation between the signal in the frequency band and the first local oscillation signal is inverted, the input signal of the subtraction unit from the output of the first frequency conversion circuit is equal to the first signal. 1 is an output signal on the opposite phase side of the differential output of the first frequency conversion circuit, and the adder input signal from the second frequency conversion circuit is the opposite phase side of the differential output of the second frequency conversion circuit. Is an image cancel mixer circuit which is an output signal of the image cancel mixer.

Further, the present invention is an image cancel mixer circuit having a phase adjustment circuit for changing or switching the phase shift adjustment amount of the phase shift synthesis circuit.

Further, according to the present invention, in the phase adjustment circuit, the phase shift adjustment amount is changed or adjusted according to a difference between a frequency conversion gain of the first frequency conversion circuit and a frequency conversion gain of the second frequency conversion circuit. This is an image cancel mixer circuit for switching.

The present invention also provides a 90 ° phase shift circuit for outputting a first local oscillation signal and a second local oscillation signal having a phase shifted by n × π / 2 from the first local oscillation signal, First
A first frequency conversion circuit for frequency-converting the frequency-converted signal according to the first local oscillation signal, and a second frequency conversion circuit for frequency-converting a second frequency-converted signal according to the first local oscillation signal A common frequency conversion circuit for frequency-converting the first frequency-converted signal and the second frequency-converted signal by the second local oscillation signal; an output of the first frequency conversion circuit and the common frequency; A first adder for adding the output of the conversion circuit; a second adder for adding the output of the second frequency conversion circuit and the output of the common frequency conversion circuit; A subtractor for subtracting the output of the common frequency converter from the output, and subtracting the output of the common frequency converter from the output of the second frequency converter; an output of the first adder and an output of the subtractor; Phase adjustment A phase-shift synthesizing circuit that adds and adjusts and adds the phase of the output of the second adding unit and the output of the subtracting unit, and a phase adjusting circuit that changes or switches the amount of phase shift adjustment of the phase-shift synthesizing circuit. And an image cancel mixer circuit comprising:

According to the present invention, the subtraction unit input signal from the first or second frequency conversion circuit output is an output signal on the opposite phase side of the differential output of the first or second frequency conversion circuit. An image cancel mixer circuit characterized in that the second adder input signal from the common frequency conversion circuit is an output signal on the opposite phase side of the differential output of the common frequency conversion circuit.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. The configuration of the image cancel mixer circuit according to the first embodiment of the present invention will be described with reference to FIG.

The image cancel mixer circuit according to the first embodiment includes a first frequency conversion circuit 1, a second frequency conversion circuit 2, an adder 3, a subtractor 4, a phase synthesizer 5, , 90 ° phase shift circuit 6. The first frequency conversion circuit 1 performs frequency conversion by multiplying the frequency conversion signal Si input from the terminal T1 by the first local oscillation signal el1, and outputs a signal S1. Second
Frequency conversion circuit 2 multiplies the frequency-converted signal Si by the second local transmission signal el2 to convert the frequency and outputs a signal S2.

The 90-degree phase shift circuit 6 comprises a doubler circuit 62 for doubling the frequency and a 1/2 frequency divider 61 for halving the frequency, and a basic local oscillation signal inputted from a terminal T2. Based on ωl, the first local oscillation signal el1 and the second
Is output. The first local oscillation signal el1 and the second local oscillation signal el2 have a phase of n × π
/ 2 (n = 1, 3, 5, 7,..., Π = 180 degrees).

The adder 3 adds the output S1 of the first frequency conversion circuit 1 and the output S2 of the second frequency conversion circuit 2 and outputs the result as an output S3. The subtraction unit 4 subtracts the other of the output S1 of the first frequency conversion circuit 1 and the output S2 of the second frequency conversion circuit 2 and outputs the result as an output S3.

The phase synthesizing circuit 5 includes a phase shifter 51 and an adder 5
2, the output S3 of the adder 3 and the output S4 of the subtractor 4 are phase-adjusted and added.

The operation of the image cancel mixer circuit according to this embodiment will be described with reference to FIG.
The frequency conversion signal Si input from the terminal T1 is the first
Are input to two frequency conversion circuits, namely, a frequency conversion circuit 1 and a second frequency conversion circuit 2. First frequency conversion circuit 1
Is converted to an intermediate frequency by multiplication with the first local oscillation signal el1, and the signal Si input to the second frequency conversion circuit 2 is converted to the second local oscillation signal el2. Is converted to an intermediate frequency.

The output S1 of the first frequency conversion circuit 1 is shown in FIG.
In the vector diagram of FIG. 2B, the output S2 of the frequency conversion circuit 2 has the phase relationship shown in the vector diagram of FIG. Here, ω1 is a frequency component of the local oscillation signal el1, and
s is a desired signal frequency component included in the frequency-converted signal Si, and ωi indicates an image interference signal frequency component included in the frequency-converted signal Si. Also, ωifs
1 and ωifs2 are desired intermediate frequency components of the output of the first frequency conversion circuit or the second frequency conversion circuit,
ωifi1 and ωifi2 indicate image intermediate frequency components in the output of the first frequency conversion circuit or the second frequency conversion circuit. The principle of the conversion operation to the intermediate frequency up to this point is the same as that described in the conventional example.

The outputs S1 and S2 of the two frequency conversion circuits 1 and 2
The addition unit 3 and the subtraction unit 4 add and subtract the signal of S2 (FIGS. 2B and 2C) to obtain an addition unit output signal S3 and a subtraction unit output signal S4. At this time, the vector diagram of the desired intermediate frequency component and the image intermediate frequency component of the adder output signal S3 is as shown in FIG. Further, the vector diagram of the desired intermediate number component and the image intermediate frequency component of the subtraction unit output signal S4 is as shown in FIG. 2 (d2), and FIG. 2 (b) ′ and FIG.
The phase difference between the two desired intermediate frequency components in (c) ′ is (π
−θ), and the phase difference between the intermediate frequency components of the two images in FIGS. 2B ′ and 2C ′ is (π + θ).

Therefore, the phase shifter 51 shown in FIG.
The phase of the desired intermediate frequency component and the image intermediate frequency component signal of the addition unit output signal S3 in (b) ′ is shifted by θ, and the desired intermediate number component and image intermediate frequency component of the subtraction unit output signal S4 in FIG. 2 (d3), only the image signal intermediate frequency component is removed as shown in FIG. 2 (e), and only the desired intermediate frequency component ωifs can be obtained.

In FIG. 2, the first frequency conversion circuit 1 and the second
Although the case where the conversion gain of the frequency conversion circuit 2 is different is shown, the output signal So from which the image signal component has been removed can be obtained even when the conversion gain is the same.

In FIGS. 1 and 2, the case where the frequency of the first local oscillation signal ω1 is higher than the frequency of the frequency-converted signal Si has been described, but the frequency of the first local oscillation signal ω1 is higher. If the frequency of the frequency-converted signal Si is lower than the frequency, the phase relationship after the frequency conversion is reversed between the desired frequency and the image signal component. Inputs an output signal on the opposite phase side of the differential output of the first frequency conversion circuit 1,
The input to the adder 3 from the second frequency conversion circuit 2 includes:
What is necessary is just to input the output signal on the opposite phase side of the differential output of the second frequency conversion circuit 2.

The configuration of the image cancel mixer circuit according to the second embodiment of the present invention will be described with reference to FIG. This embodiment is characterized in that a phase adjustment unit 7 is provided in the image cancellation mixer circuit according to the first embodiment.

The phase adjuster 7 includes a first frequency converter 1
And the conversion gain of the second frequency conversion circuit 2
In accordance with the difference, the phase shift amount of one or both of the outputs of the first frequency conversion circuit 1 and the second frequency conversion circuit 2 is changed so that the image signal component can be removed from the output of the phase synthesis circuit 5. adjust. As an adjustment method, the conversion gain at the output S1 of the first frequency conversion circuit 1 and the output S2 of the second frequency conversion circuit 2 is measured, and the amount of phase shift is determined based on the measurement result. Then, the phase shift amount is added to the output S3 of the adder 3. In this way, by adjusting the amount of phase shift, the output of the phase synthesis circuit 5
Adjustments can be made to completely remove the image signal component at any amplitude error.

In the description of this embodiment, the phase of the output signal S3 of the adder 3 is adjusted. However, the phase shifter 51 changes the phase only with the output signal S3 of the adder 3. The adjustment need not be performed, and the adjustment may be performed by one or both of the adding unit 3 and the subtracting unit 4.

A third embodiment of the present invention will be described with reference to FIG. This embodiment relates to a dual-band image cancel mixer circuit having an image cancel function of two kinds of frequency bands as shown in the block diagram of FIG. The dual band image canceling circuit includes a first frequency conversion circuit 1, a shared frequency conversion circuit 2, a first addition unit 3, a subtraction unit 4, a phase synthesis circuit 5, a 90-degree phase shift circuit 6, 2 frequency conversion circuit 8,
The second adder 9 is provided.

The first frequency conversion circuit 1 multiplies the first frequency-converted signal Si1 input from the terminal T1 by the first local oscillation signal el1 to convert the frequency and outputs it as an output S1. The second frequency conversion circuit 8 performs frequency conversion by multiplying the second frequency-converted signal Si2 input from the terminal T4 by the first local transmission signal el1, and outputs the result as an output S1 '. The shared frequency conversion circuit 2 performs frequency conversion by multiplying the first frequency-converted signal Si1 or the second frequency-converted signal Si2 by the second local transmission signal el2, and outputs the result as an output S2.

The 90-degree phase shift circuit 6 is composed of a doubling circuit 62 for doubling the frequency and a 1/2 frequency divider 61 for halving the frequency, and a basic local oscillation signal inputted from a terminal T2. Based on ωl, the first local oscillation signal el1 and the second
Is output. The first local oscillation signal el1 and the second local oscillation signal el2 have a phase of n × π
/ 2 (n = 1, 3, 5, 7,..., Π = 180 degrees).

The first adder 3 adds the output S1 of the first frequency conversion circuit 1 and the output S2 of the shared frequency conversion circuit 2, and outputs an output S3. The second adder 9 outputs the second
Of the frequency conversion circuit 8 and the output S2 of the shared frequency conversion circuit 2 to output an output S3 '.

The subtractor 4 subtracts the output S2 of the shared frequency conversion circuit 2 from the output S1 of the first frequency conversion circuit 1 or the output S1 'of the second frequency conversion circuit 8, and outputs an output S4.

The phase synthesizing circuit 5 adjusts the phase of the output S3 of the first adding section 3 or the output S3 'of the second adding section 9 and the output S4 of the subtracting section 4, adds and outputs the output So. .

When the input of the signal Si1 in the first frequency band is frequency-converted, the first frequency conversion circuit 1 and the shared frequency conversion circuit 2 are operated, but the second frequency conversion circuit 8 is turned off. When performing frequency conversion on the input of the signal Si2 in the second frequency band, the second frequency conversion circuit 8
And the shared frequency conversion circuit 2 is operated, but the first frequency conversion circuit 1 is turned off. Focusing on the block configuration excluding the frequency conversion circuit that is turned off, the configuration is the same as that shown in FIGS. 1 and 2, and the operation principle is the same as that of FIG. 2.

Since the two frequency conversion circuits, the first frequency conversion circuit 1 and the second frequency conversion circuit 8, are optimized in their respective frequency bands, the frequency conversion gains may be different. In this case, one frequency conversion circuit is required for each frequency band, and as shown in FIG. 9, two frequency conversion circuits are provided for one frequency band. However, in this embodiment, since the shared frequency conversion circuit 2 is shared, one less frequency conversion circuit can be configured. Further, in this embodiment, even in the image cancellation mixer circuit configured by the frequency conversion circuits having different conversion gains, since the image cancellation mixer circuit includes the phase adjustment unit 7, it is possible to switch to the phase amount corresponding to the two frequency bands. It is possible to completely remove the image signal component in any frequency band, and a dual band image cancel mixer circuit can be realized.

Referring to FIG. 5, the configuration of the triple band image cancel mixer circuit according to the fourth embodiment of the present invention will be described. This embodiment relates to a triple band image cancel mixer circuit having an image cancel function of three kinds of frequency bands. As shown in FIG. 5, the triple band image cancel mixer circuit includes a first frequency conversion circuit 1 and a shared frequency conversion circuit 2.
, A first adding unit 3, a subtracting unit 4, and a phase synthesizing circuit 5.
A 90-degree phase shifter 6, a phase adjuster 7, a second frequency converter 8-1, a third frequency converter 8-2,
A second adder 9-1 and a third adder 9-2 are provided. Compared with the third embodiment, the frequency band is 2
Since the number of types is increased by three, the frequency conversion circuit and the adding unit are increased by one.

As described above, in the image cancel mixer circuit having the image cancel function of two or more kinds of frequency bands, similarly to the dual band cancel mixer circuit of the third embodiment, the shared frequency conversion circuit 2 is used. Therefore, it is possible to reduce the increase in the number of frequency conversion circuits, and it is possible to configure the number of (frequency bands to be handled + 1) frequency conversion circuits.

As described in connection with the embodiment of FIG. 1, the input signal of the adder / subtractor depends on the desired frequency to be inputted and the frequency arrangement of the local oscillation signal. , The frequency conversion circuit 2 can be shared even when the operation of a plurality of frequency bands is provided.

[0053]

As described above, according to the present invention, even if there is an amplitude error in the frequency conversion circuit, the image signal component can be completely removed, and the image canceling mixer for a plurality of frequency bands is built in. In this case, it is possible to obtain an image cancellation mixer circuit capable of reducing the number of elements.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image cancellation mixer circuit according to a first embodiment of the present invention.

FIG. 2 is a vector diagram illustrating an operation of the image cancellation mixer circuit according to the first embodiment.

FIG. 3 is a block diagram of an image cancel mixer circuit according to a second embodiment of the present invention.

FIG. 4 is a block diagram of an image cancellation mixer circuit according to a third embodiment of the present invention.

FIG. 5 is a block diagram of an image cancellation mixer circuit according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional image cancel mixer circuit.

FIG. 7 is a first vector diagram illustrating an operation of a conventional image cancel mixer circuit.

FIG. 8 is a second vector diagram for explaining the operation of the conventional image cancellation mixer circuit.

FIG. 9 is a block diagram showing a configuration of a conventional dual band image cancel mixer circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st frequency conversion circuit 2 2nd frequency conversion circuit (shared frequency conversion circuit) 3 addition part 4 subtraction part 5 phase synthesizer 51 phase shifter 52 addition part 6 90 degree phase shift circuit 61 1/2 half cycle 62 Doubler 7 Phase adjuster 8 Second frequency converter 9 Second adder S1 Output of first frequency converter S2 Output of second frequency converter S3 Output of adder S4 Output of subtractor Si1 First Frequency band signal Si2 Second frequency band signal el1 First local oscillation signal el2 Second local oscillation signal

Claims (6)

[Claims] 1. A first local oscillation signal and a phase of n × π / 2 (n = 1, 3, 5, 7,...) From the first local oscillation signal.
.., Π = 180 degrees) A 90-degree phase shift circuit that outputs a second local oscillation signal that is shifted, and a first frequency conversion circuit that frequency-converts a frequency-converted signal using the first local oscillation signal. A second frequency conversion circuit for frequency-converting the frequency-converted signal by the second local oscillation signal, and a phase adjustment between an output of the first frequency conversion circuit and an output of the second frequency conversion circuit. An image cancel mixer circuit comprising: a phase shift synthesizing circuit for adding; an adder for adding an output of the first frequency conversion circuit and an output of the second frequency conversion circuit; and the first frequency conversion circuit. And a subtraction unit for subtracting the output of the second frequency conversion circuit from the output of the phase shifter, wherein the phase-shift synthesizing circuit adjusts the phase of the output of the addition unit and the output of the subtraction unit and adds them. Cap Serumikusa circuit. 2. The image cancel mixer circuit according to claim 1, wherein when the frequency arrangement of the signal in the frequency band and the first local oscillation signal is inverted, the output from the first frequency conversion circuit output is changed. The subtraction unit input signal is an output signal on the opposite phase side of the differential output of the first frequency conversion circuit, and the addition unit input signal from the second frequency conversion circuit is output from the second frequency conversion circuit. An image cancellation mixer circuit, which is an output signal on the opposite phase side of the differential output. 3. The image cancellation mixer circuit according to claim 1, further comprising: a phase adjustment circuit that changes or switches a phase shift adjustment amount of the phase shift synthesis circuit. . 4. The image cancellation mixer circuit according to claim 3, wherein said phase adjustment circuit is responsive to a difference between a frequency conversion gain of said first frequency conversion circuit and a frequency conversion gain of said second frequency conversion circuit. An image cancellation mixer circuit characterized by varying or switching a phase shift adjustment amount. 5. A 90-degree phase shifter for outputting a first local oscillation signal and a second local oscillation signal having a phase shifted by n × π / 2 from the first local oscillation signal, A first frequency conversion circuit that converts the frequency of the frequency-converted signal using the first local oscillation signal, a second frequency conversion circuit that converts a second frequency-converted signal using the first local oscillation signal, The first frequency-converted signal and the second
A common frequency conversion circuit that frequency-converts the frequency-converted signal according to the second local oscillation signal, and a first addition unit that adds the output of the first frequency conversion circuit and the output of the common frequency conversion circuit. A second adder for adding the output of the second frequency conversion circuit and the output of the common frequency conversion circuit, and subtracting the output of the common frequency conversion circuit from the output of the first frequency conversion circuit; and A subtraction unit for subtracting the output of the common frequency conversion circuit from the output of the second frequency conversion circuit; and adjusting and adding the phases of the output of the first addition unit and the output of the subtraction unit; An image canceller comprising: a phase-shift synthesizing circuit that adjusts and adds the phase of the output of the subtraction unit and the output of the subtraction unit; Mixer circuit. 6. The image cancellation mixer circuit according to claim 5, wherein a subtraction unit input signal from the first frequency conversion circuit output or the second frequency conversion circuit output is supplied to the first frequency conversion circuit or the second frequency conversion circuit. And the second adder input signal from the common frequency conversion circuit is a signal on the opposite phase side of the differential output of the common frequency conversion circuit. An image cancellation mixer circuit, which is an output signal.