阅读说明：本技术 一种数字正交混频器混频方法、混频器电路和混频器 (Frequency mixing method of digital quadrature frequency mixer, frequency mixer circuit and frequency mixer ) 是由 刘明雄 姚亚峰 付东兵 于 2021-05-13 设计创作，主要内容包括：本发明提供了一种数字正交混频器混频方法、混频器电路和混频器,相位累加器通过输入的FTW(频率控制字)、POW(相位控制字)来得到当前相位,相位选择器根据实混频复混频得到两个不同的相位值,相幅转换器采用三段式cordic算法得到混频所需要的cos,sin本振信号,最终在优化后的混频器中进行乘加运算,完成混频。由于电路设计中乘法器会占用很大的面积,通过优化后会减少乘法器个数,资源消耗减少很多。(The invention provides a frequency mixing method of a digital orthogonal frequency mixer, a frequency mixer circuit and a frequency mixer.A phase accumulator obtains a current phase through an input FTW (frequency control word) and an input POW (phase control word), a phase selector obtains two different phase values according to real frequency mixing complex frequency mixing, a phase-amplitude converter obtains cos and sin local oscillation signals required by frequency mixing by adopting a three-section cordic algorithm, and finally multiplication and addition operation is carried out in the optimized frequency mixer to finish frequency mixing. As the multiplier occupies a large area in the circuit design, the number of the multipliers can be reduced after optimization, and the resource consumption is greatly reduced.)

1. A digital quadrature mixer mixing method, comprising:

the digital quadrature mixer sequentially comprises a phase accumulator, a phase selector, a phase-amplitude converter and a mixer;

the phase accumulator accumulates phases in time by using input frequency control words and phase control words;

the phase selector generates a phase value corresponding to a real mixing mode or a complex mixing mode through accumulation of the phases;

the phase-amplitude converter outputs cosine local oscillation signals and sine local oscillation signals by utilizing a three-section cordic algorithm according to the phase value;

the mixer performs digital operation on the cosine local oscillator signal, the sine local oscillator signal, the I path input signal and the Q path input signal to perform frequency mixing, performs three times of multiplication and four times of addition operation to perform frequency mixing through a multiplier and an adder during frequency mixing in a complex frequency mixing mode, and performs two times of multiplication operation to perform frequency mixing in a real frequency mixing mode.

2. The digital quadrature mixer mixing method of claim 1, wherein said phase selector generating phase values corresponding to a real mixing mode or a complex mixing mode by accumulation of said phases further comprises:

the accumulation of the phase in time is realized through an adder and a trigger, and when the mixing mode is real mixing, the amplitude of phase selection does not need to be increased;

when the mixing mode is complex mixing, the amplitude of the phase selector is increased by pi/4.

3. The digital quadrature mixer mixing method of claim 1, wherein said mixer is configured to perform digital operations on said cosine local oscillator signal, said sine local oscillator signal, and said I and Q input signals to perform mixing, comprising:

adding the sine local oscillation signal and the cosine local oscillation signal to obtain an Ac1 signal;

adding the I path input signal and the Q path input signal to obtain an Ac2 signal;

multiplying Ac1 and Ac2 to obtain a first signal pro 1;

performing multiplication operation on the cosine local oscillator signal and the Q-path input signal to obtain a second signal pro 2;

and multiplying the sinusoidal local oscillation signal and the I-path input signal to obtain a third signal pro 3.

4. The digital quadrature mixer mixing method of claim 3, further comprising:

and performing sum-angle formula transformation on the cosine local oscillation signals and the sine local oscillation signals in the first signal pro1, the second signal pro2 and the third signal pro3 to obtain cosine local oscillation signals and sine local oscillation signals with new frequencies.

5. The digital quadrature mixer mixing method of claim 4, further comprising:

and substituting the cosine local oscillation signal with the new frequency and the sine local oscillation signal with the new frequency into a first signal pro1, a second signal pro2 and a third signal pro3, and performing amplitude attenuation to obtain a new pro1 signal, a new pro2 signal and a new pro3 signal.

6. The digital quadrature mixer mixing method of claim 5, further comprising:

and adding the new pro1 signal and the new pro2 signal by an adder to obtain an output signal of the I-path of the mixer.

7. The digital quadrature mixer mixing method of claim 6, further comprising:

and subtracting the new pro1 signal and the new pro3 signal to obtain an output signal of the Q-path of the mixer.

8. A digital quadrature mixer circuit for implementing a digital quadrature mixer mixing method according to any of claims 1-7, the mixer circuit comprising:

a first adder, a second adder, a third adder, a fourth adder, a first multiplier, a second multiplier and a third multiplier;

the signal output ends of the first adder and the second adder are respectively connected with the signal input end of the first multiplier;

the signal output end of the first multiplier is connected with the signal input end of the fourth adder;

the signal output end of the first multiplier is also connected with the signal output end of the third adder;

the signal output end of the second multiplier is connected with the signal input end of the third adder, and the signal output end of the third adder is used for outputting an I-path mixing signal;

and the signal output end of the third multiplier is connected with the signal input end of the fourth adder, and the fourth signal output end is used for outputting a Q-path mixing signal.

9. A digital quadrature mixer having a digital quadrature mixer mixing circuit according to claim 8 carried thereon, said quadrature mixer being adapted to implement a digital quadrature mixer mixing method according to any of claims 1 to 7.

Technical Field

The invention relates to the technical field of digital integrated circuit design, in particular to a frequency mixing method of a digital quadrature frequency mixer, a frequency mixer circuit and a frequency mixer.

Background

In current digital mixer designs, the circuit is usually formed directly, in contrast to schematic diagrams. The real mixing structure is simple, only two multiplications are needed to realize, but the complex mixing is relatively complex, four multiplications and two additions are needed to realize, and the maximum value of the signal frequency is enlarged to the previous value due to the characteristic of the complex mixingAnd (4) doubling. Two multipliers are also needed for amplitude attenuation, so that six multipliers and two adders are needed in total, and the multipliers occupy large area in circuit design because of the fact thatFor this circuit, a multiplier operation is required when the amplitude is attenuated, and the resource consumption is large.

Disclosure of Invention

The invention solves a main problem of providing a novel digital quadrature mixer, which reduces the use of multipliers and reduces resource consumption.

According to an aspect of the present invention, there is provided a digital quadrature mixer mixing method, including:

the digital quadrature mixer sequentially comprises a phase accumulator, a phase selector, a phase-amplitude converter and a mixer;

the phase accumulator accumulates phases in time by using input frequency control words and phase control words;

the phase selector generates a phase value corresponding to a real mixing mode or a complex mixing mode through accumulation of the phases;

the phase-amplitude converter outputs cosine local oscillation signals and sine local oscillation signals by utilizing a three-section cordic algorithm according to the phase value;

the mixer performs digital operation on the cosine local oscillator signal, the sine local oscillator signal, the I path input signal and the Q path input signal to perform frequency mixing, performs three times of multiplication and four times of addition operation to perform frequency mixing through a multiplier and an adder during frequency mixing in a complex frequency mixing mode, and performs two times of multiplication operation to perform frequency mixing in a real frequency mixing mode.

Furthermore, the accumulation of the phase in time is realized through an adder and a trigger, and when the mixing mode is real mixing, the amplitude of the phase selector does not need to be increased;

when the mixing mode is complex mixing, the amplitude of the phase selector is increased by pi/4.

Further, performing addition operation on the sine local oscillation signal and the cosine local oscillation signal to obtain an Ac1 signal;

adding the I path input signal and the Q path input signal to obtain an Ac2 signal;

multiplying Ac1 and Ac2 to obtain a first signal pro 1;

performing multiplication operation on the cosine local oscillator signal and the Q-path input signal to obtain a second signal pro 2;

and multiplying the sinusoidal local oscillation signal and the I-path input signal to obtain a third signal pro 3.

Further, cosine local oscillation signals and sine local oscillation signals in the first signal pro1, the second signal pro2 and the third signal pro3 are subjected to sum and angle formula conversion to obtain cosine local oscillation signals and sine local oscillation signals of new frequencies.

Further, the cosine local oscillator signal with the new frequency and the sine local oscillator signal with the new frequency are substituted into the first signal pro1, the second signal pro2 and the third signal pro3, and amplitude attenuation is performed to obtain a new pro1 signal, a new pro2 signal and a new pro3 signal.

Further, the new pro1 signal and the new pro2 signal are added by an adder to obtain the output signal of the mixer I-path.

Further, the new pro1 signal and the new pro3 signal are subtracted to obtain the output signal of the Q-path of the mixer.

According to another aspect of the present invention, there is also disclosed a digital quadrature mixer circuit for implementing a digital quadrature mixer mixing method as described in any of the preceding, the mixer circuit comprising:

a first adder, a second adder, a third adder, a fourth adder, a first multiplier, a second multiplier and a third multiplier;

the signal output ends of the first adder and the second adder are respectively connected with the signal input end of the first multiplier;

the signal output end of the first multiplier is connected with the signal input end of the fourth adder;

the signal output end of the first multiplier is also connected with the signal output end of the third adder;

the signal output end of the second multiplier is connected with the signal input end of the third adder, and the signal output end of the third adder is used for outputting an I-path mixing signal;

and the signal output end of the third multiplier is connected with the signal input end of the fourth adder, and the fourth signal output end is used for outputting a Q-path mixing signal.

According to a further aspect of the present invention, there is also disclosed a digital quadrature mixer on which a digital quadrature mixer circuit as described above is carried, the quadrature mixer being adapted to implement a digital quadrature mixer mixing method as described in any of the preceding.

In the frequency mixing method of the digital orthogonal frequency mixer, a phase selector module is added in a frequency mixer device, and a frequency mixer circuit module is optimized to enable two paths of signals I and Q input from the outside and local oscillator signals cos and sin generated by phase selection to perform multiplication and addition operation.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is an overall structural diagram of a digital quadrature mixer according to an embodiment of the present invention.

Fig. 2 is a circuit diagram of a phase accumulator according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an optimized structure of a mixer circuit according to an embodiment of the invention.

Wherein, 1-first adder, 2-second adder, 3-third adder, 4-fourth adder, 5-first multiplier, 6-second multiplier and 7-third multiplier

Detailed Description

Various exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

As shown in fig. 1, the overall structure of the digital quadrature mixer of the present invention includes a phase accumulator, a phase selector, a phase-amplitude converter and a mixer; the phase accumulator obtains the current phase through the input FTW (frequency control word) and POW (phase control word); the phase selector obtains two different phase values according to real mixing complex mixing; the phase-amplitude converter adopts a three-section cordic algorithm to obtain cos and sin local oscillator signals required by frequency mixing, and finally multiplication and addition operation is carried out in a frequency mixer to complete frequency mixing;

the three-section cordic algorithm is specifically implemented by the following steps:

the method comprises the steps of firstly searching a rom, then performing approximate iterative operation, and finally performing iterative operation of the last steps, thereby reducing circuit delay.

As shown in fig. 2, which is a schematic circuit diagram of a phase accumulator module, the phase accumulator module implements phase accumulation over time through an adder and a trigger, that is, the phase accumulator module is used to calculate the phase of a current sine local oscillator signal, if an input frequency control word FTW is 16 bits, the phase accumulator needs to implement a 16-bit adder, the current phase is determined by the value of the adder at each time, and specific values of the current cos and sin local oscillator signals are determined by the phase.

The conventional principle of quadrature mixer mixing is: mixing is generally divided into two categories, real mixing, where the input is seen as a real signal cos (ω)₀nT), respectively connecting one path of signal with a local oscillator signal cos (omega)₁nT)+j*sin(ω₁nT), the input IQ signals are set to be the same, namely, (1) and (2):

real mixing can be viewed as shifting the signal spectrum to both sides, producing a baseband component ω₀-ω₁And a high frequency component omega₀+ω₁High frequency components are usually eliminated after filtering by a filter, so that signals are attenuated after filtering by real mixing; the complex mixed frequency input is regarded as a complex signal and divided into two paths of I and Q, namely a real part and an imaginary part cos (omega) respectively₀nT)+jsin(ω₀nT), and the two parts are compared with a local oscillator signal cos (ω)₁nT)+j*sin(ω₁nT), obtaining a final result, wherein the input IQ signals are:

wherein, ω is₀、ω₁The different local oscillator angular frequencies are respectively, n is (123 … … n), T is the sampling interval time, the complex mixing frequency is to shift the input signal to the baseband on the frequency spectrum in one way, no extra component is generated, no attenuation is caused by passing through the filter, but the attenuation is caused by passing through the filterAfter complex mixing, full amplitude of IQ two-path signals can be enlargedIn order to optimize the multiplication used by the amplitude attenuation of IQ two-path output, the embodiment of the invention reduces two multiplication operations in the mixer circuit, thereby greatly reducing the resource consumption.

Fig. 3 shows a specific structure of the optimized mixer circuit:

the mixer comprises a first adder 1, a second adder 2, a third adder 3, a fourth adder 4, a first multiplier 5, a second multiplier 6 and a third multiplier 7;

the signal output ends of the first adder 1 and the second adder 2 are respectively connected with the signal input end of the first multiplier 5;

the signal output end of the first multiplier 5 is connected with the signal input end of the fourth adder 4;

the signal output end of the first multiplier 5 is also connected with the signal output end of the third adder 3;

the signal output of the second multiplier 6 is connected to the signal input of the third adder 3,

the signal output end of the third adder 3 is used for outputting an I-channel mixing signal;

and a signal output end of the third multiplier 7 is connected with a signal input end of the fourth adder 4, and the fourth signal output end is used for outputting a Q-path mixing signal.

The mixing principle in the mixer carrier complex mixing mode is as follows: firstly, selecting cos local oscillation signals, sin local oscillation signals, I paths of input signals and Q paths of input signals according to a frequency mixing mode (real frequency mixing or complex frequency mixing);

the mixing method of the present embodiment is applied to the digital down-conversion module, so the result of complex mixing can be regarded as (5) and (6), where I, Q is the input signal:

firstly, we can combine the input signal and the local oscillator signal two by two to obtain three new signals:

pro1＝(I+Q)*cos(ω₁nT) (7)

pro2＝(sin(ω₁nT)-cos(ω₁nT))*Q (8)

pro3＝(sin(ω₁nT)+cos(ω₁nT))*I (9)

then, local oscillation signals in the signals (7) - (9) are subjected to the conversion of the angle formula, and new signals (10) - (12) are obtained:

next, ω in the formulas (10), (11) and (12) is expressed₁Replacement of nT + π/4 by ω₂nt, obtaining a local oscillation signal form of a new frequency, replacing the local oscillation signal of the new frequency into signals (7) - (9), and performing amplitude attenuation to obtain a new pro1 output signal, a new pro2 output signal and a new pro3 output signal:

pro1＝1/2(I+Q)*(sin(ω₂nT)+cos(ω₂nT)) (13)

pro2＝-(cos(ω₂nT))*Q (14)

pro3＝(sin(ω₂nT))*I (15)

finally, the I-path output signal is obtained by adding the new pro1 output signal and the new pro2 output signal, and the Q-path output signal is obtained by subtracting the new pro1 output signal and the new pro3 output signal:

l road-pro 1+ pro2 (16)

Q way pro1-pro3 (17)

Wherein, ω is₂When real mixing is used for replacing a mixer mixing method after local oscillator signal angular frequency optimization, the phase does not need to be added with pi/4, extra addition multiplication does not need to be used in the mixer, the mixer mixing method is realized through a selector, complex mixing is carried out above the selector, real mixing is carried out below the selector, the selector which is selected by 0 and 0 can ensure that the signal value is not changed when the real mixing is carried out, and the circuit does not turn over 01 and has no dynamic power consumption; timing problems and phase problems of signals in the circuit need to be considered when the method is specifically realized, and a good pipeline structure is used.

The multiplier occupies the largest resource consumption in the digital circuit, the optimized mixing method of the mixer circuit and the orthogonal mixer can reduce the chip area and the power consumption, reduce the resource consumption and achieve the same effect as the traditional mixing device, and compared with the prior art, the method reduces three multipliers in total.

The above description is only exemplary of the present invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and scope of the present invention should be included in the present invention.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.