CN101373950B - Frequency-mixing apparatus and correlation method - Google Patents

Abstract

The invention relates to a frequency mixing device, which can design harmonic item times to be filtered according to the needs so as to promote the representation of the circuit characteristics. In addition, the harmonic interference phenomenon can be improved greatly through the frequency mixing device no matter which type of frequency mixing circuits is adopted by the frequency mixing device.

Description

Mixer device and correlation technique

Technical field

The present invention relates to a kind of frequency mixer, particularly relate to the frequency mixer that is used for the harmonic wave rejection.

Background technology

In many data communication circuit, frequency mixer is an important member.Frequency mixer carries out mixing in order to a received signal and a clock signal LO.Above-mentioned processing mode except meeting produces desirable mixed frequency signal, also can produce the harmonic term of not expecting, and then interferes with the data that will transmit, and reduces signal to noise ratio (Signal-to-Noise Ratio/SNR) greatly, causes the usefulness of receiver to reduce.

Fig. 1 shows the functional block diagram in order to the known technology that overcomes harmonic problem.The functional block diagram 100 of this known technology, comprise an antenna (Antenna) 102, a low noise amplifier (Low NoiseAmplifier/LNA) 104, one frequency mixer (Mixer) 105, a filter 106, a filter 107 and a frequency synthesizer (Frequency Synthesizer) 108, wherein frequency synthesizer 108 can provide a clock signal LO.The signal processing mode of above-mentioned Fig. 1 is the harmonic wave that utilizes filter 107 not want with filtering; At last, produce the intermediate-freuqncy signal I (Intermediate Frequency/IF) or the fundamental frequency signal B (Baseband Frequency) of a no harmonic wave.

Traditionally, filter 107 mostly be adopt as: LC filter (LC Filter), transduction filter (Gm-C Filter) and OP-RC filter (OP-RC Filter) ... wait filter to realize.If adopt the LC filter; Because the numerical value of L is very big,, will certainly makes chip area strengthen and make chip cost increase as filter 107 is made in chip internal; As L is made in chip exterior, also be to increase extra cost.If be to adopt Gm-C filter or OP-RC filter to realize, can make then noise factor (Noise Figure) increase, and cause the linearity (Linearity) to descend that the performance of integrated circuit characteristic i.e. variation significantly.But, no matter adopt how good again filter, all still be to increase area of chip, and will increase cost.

Can be learnt obviously that by above-mentioned explanation known technology is except cost comparatively the costliness, its circuit characteristic also can't reach the standard of the Harmonic Interference that those skilled in the art will solve.Therefore, need a kind of invention of novelty to solve the long-term problem that is run in above-mentioned this field.

Summary of the invention

One of purpose of the present invention is to provide a kind of mixer device that is used for the harmonic wave rejection, to solve the above problems.

One of purpose of the present invention is to provide a kind of mixer device that is used for the harmonic wave rejection, can solve the interference of various different frequency harmonic waves according to need.

The invention provides in the equivalent function square framework of a wave-mixing device, can also want the harmonic term of filtering inferior, and then promote the performance of circuit characteristic at self-demand design.And no matter wave-mixing device is the mixting circuit that adopts which kind of kind, pattern, and the phenomenon of Harmonic Interference all can be improved significantly by the present invention.In addition, the chip designer also can come design circuit according to the harmonic term of wanting filtering of self, to this, then has more elasticity on circuit design.

Description of drawings

Fig. 1 is the functional block diagram in order to the known technology that overcomes Harmonic Interference.

Fig. 2 is the functional block diagram according to an embodiment of mixer device of the present invention.

Fig. 3 (a) is the functional block diagram according to an embodiment of mixer device of the present invention.

Fig. 3 (b) is the functional block diagram according to an embodiment of mixer device of the present invention.

Fig. 3 (c) is the functional block diagram according to an embodiment of mixer device of the present invention.

Fig. 3 (d) is the functional block diagram according to an embodiment of mixer device of the present invention.

Fig. 4 is that the circuit of the embodiment of Fig. 2, Fig. 3 (a) and Fig. 3 (b) is realized figure.

Fig. 5 is that the circuit of another embodiment of Fig. 2, Fig. 3 (a) and Fig. 3 (b) is realized figure.

Fig. 6 is that the circuit of the embodiment of Fig. 2, Fig. 3 (c) and Fig. 3 (d) is realized figure.

The reference numeral explanation

100 functional block diagram in order to the known technology that overcomes Harmonic Interference

102 antennas, 104 low noise amplifiers

105 frequency mixers, 106 filters

107 filters, 108 frequency synthesizers

200 mixer devices

201 mixting circuits, 202 first circuit

203 second circuits, 204 tertiary circuits

205 add up the unit

2021,2031,2041 gain units

2012,2022,2032,2042 mixing unit

300 mixer devices

301 first gain units, 302 second gain units

303 the 3rd gain units 304 the 4th gain unit

306 second mixing unit, 305 first mixing unit

The 4th mixing unit, 307 the 3rd mixing unit 408

309 add up the unit

310 mixer devices

312 second mixing unit, 311 first mixing unit

The 4th mixing unit, 313 the 3rd mixing unit 314

315 first gain units, 316 second gain units

317 the 3rd gain units 318 the 4th gain unit

319 add up the unit

320 mixer devices

321 first gain units, 322 second gain units

323 the 3rd gain units 324 the 4th gain unit

326 second mixing unit, 325 first mixing unit

The 4th mixing unit, 327 the 3rd mixing unit 328

329 add up the unit

The functional block diagram of one embodiment of 330 a kind of frequency mixers of the present invention

332 second mixing unit, 331 first mixing unit

The 4th mixing unit, 333 the 3rd mixing unit 334

335 first gain units, 336 second gain units

337 the 3rd gain units 338 the 4th gain unit

339 add up the unit

The circuit of the embodiment of 400 Fig. 2, Fig. 3 (a) and Fig. 3 (b) is realized figure

The circuit of another embodiment of 500 Fig. 2, Fig. 3 (a) and Fig. 3 (b) is realized figure

The circuit of another embodiment of 600 Fig. 2, Fig. 3 (c) and Fig. 3 (d) is realized figure

v _In(+), v _In(-) input signal

V _O(+), V _O(-) output signal

LO1(+)、LO2(+)、LO3(+)、LO4(+)、

LO1 (-), LO2 (-), LO3 (-), LO4 (-) local oscillator signals

Embodiment

In specification and claim, used some vocabulary to censure specific assembly.Those skilled in the art should understand, and this specification and claims are not used as distinguishing the mode of assembly with the difference of title, but the criterion that is used as distinguishing with the difference of assembly on function.Be an open term mentioned " comprising " in specification and claim, so should be construed to " comprise but be not limited to ".In addition, " couple " speech and comprise any indirect means that are electrically connected that directly reach at this.

Past all is will cause the harmonic wave of interference to give filtering by a filter; And the invention provides a mixer device, at least one harmonic term of the mixer output signal of its output has been eliminated in mixer device, utilizes at least one filter to do the operation of harmonic filtration so can omit.So, not only dwindle area of chip more, also reduced cost relatively, promoted the competitiveness of price.In addition, also can be according to purpose of design required, decide want filtering which time harmonic term, so ten minutes has elasticity in design.Compared to known technology, not only at chip area, still on price and design flexibility, all be a very big improvement.

Principle of the present invention can illustrate by fourier series (Fourier Series), with convenient understanding the present invention.Can be known by inference by fourier series, signal LO (t) is by once in fact, three times, and five times, seven times ... the string ripple that waits is formed, the following equation that shows:

$\mathrm{LO}\left(t\right)=\sin \left(w_{0}t\right)+\frac{\sin \left(3w_{0}t\right)}{3}+\frac{\sin \left(5w_{0}t\right)}{5}+\frac{\sin \left(7w_{0}t\right)}{7}+\frac{\sin \left(9w_{0}t\right)}{9}+\frac{\sin \left(11w_{0}t\right)}{11}+.....$

Wherein,

Deng, belong to the harmonic term part that can cause interference to signal.Therefore, as long as can cause the harmonic term of interference to be rejected these, just can promote SNR numerical value and obtain a good circuit characteristic performance.So the present invention promptly utilizes this principle, reaches the purpose of harmonic wave rejection; Described harmonic term is given cancellation from equation, can utilize following equation to realize:

$V_{\mathrm{out}}\left(t\right)$

$=R\left(t\right)\×(\sin \left(w_{0}t\right)+\frac{\sin \left(3w_{0}t\right)}{3}+\frac{\sin \left(5w_{0}t\right)}{5}+...)-\frac{1}{3}R\left(t\right)\×(\sin \left(3w_{0}t\right)+\frac{\sin \left(9w_{0}t\right)}{3}+\frac{\sin \left(15w_{0}t\right)}{5}+...)$

$=R\left(t\right)\×(\sin \left(w_{0}t\right)+\frac{\sin \left(5w_{0}t\right)}{5}+...)$

Aforesaid equation promptly fully gives filtering with the triple-frequency harmonics item.In like manner, also can adopt identical gimmick, with triple-frequency harmonics item, quintuple harmonics item, the seventh harmonic item ... wait the processing of doing filtering.

Please refer to Fig. 2, it is the functional block diagram according to an embodiment of a kind of mixer device that is used for the harmonic wave rejection of the present invention.

As shown in Figure 2, this mixer device 200 that is used for the harmonic wave rejection comprises a mixting circuit 201, one first circuit 202, a second circuit 203, a tertiary circuit 204 and a totalling unit 205.This mixting circuit 201 also comprises a mixing unit 2012, and it is in order to receive a signal s and a f _o, and by this mixing unit 2012 to this signal s and f _oCarry out mixing to produce a signal s ₁This first circuit 202 also comprises a gain unit 2021 and a mixing unit 2022, and it is in order to receive this signal s and 3f _o, and by this gain 2021 and this mixing unit 2022 to this signal s and 3f _oCarry out mixing to produce a signal s ₂This second circuit 203 also comprises a gain unit 2031 and a mixing unit 2032, and it is in order to receive this signal s and 5f _o, and by this gain 2031 and this mixing unit 2032 to this signal s and 5f _oCarry out mixing to produce a signal s ₃This tertiary circuit 204 also comprises a gain unit 2041 and a mixing unit 2042, and it is in order to receive a signal s and a 7f _o, and by this gain unit 2041 and this mixing unit 2042 to this signal s and 7f _oCarry out mixing to produce a signal s ₄The signal of wherein said gain unit 2021,2031 and 2041 in order to this conversion of signals is become to have its gain values, the harmonic signal of described mixing unit 2022,2032 and 2042 in order to eliminate with the generation desire as the processing of two signals being done mixing.At last, add up unit 205 with this signal s by this again ₁, s ₂, s ₃And s ₄Added the output s ' of the General Logistics Department.

Wherein, this first circuit (that is, gain unit 2021 and mixing unit 2022) can be considered triple-frequency harmonics elimination circuit; This second circuit (that is, gain unit 2031 and mixing unit 2032) can be considered quintuple harmonics and eliminates circuit; This tertiary circuit (that is, gain unit 2041 and mixing unit 2042) can be considered the seventh harmonic and eliminates circuit.In addition, comprised triple-frequency harmonics item, nine subharmonic items, ten quintuple harmonics items because triple-frequency harmonics is eliminated in the signal that circuit produced ... etc. harmonic term, so in the present embodiment, nine subharmonic are eliminated circuit can.In addition, as shown in Figure 2, the embodiment that this harmonic wave is eliminated circuit also is a frequency mixer, its difference be this clock signal frequency for the N of the clock signal of this mixting circuit 201 doubly, its yield value is 1/N a times of this mixting circuit 201.In addition, f _o, 3f _o, 5f _o, 7f _oProduced by a clock signal generator, embodiment can be: frequency synthesizer, phase-locked loop (PLL) ... etc.

Please refer to Fig. 3 (a), Fig. 3 (b), Fig. 3 (c) and Fig. 3 (d).Fig. 3 (a), Fig. 3 (b), Fig. 3 (c) and Fig. 3 (d) also are the functional block diagram of the various embodiment of the mixer device that is used for the harmonic wave rejection according to Fig. 2 of the present invention a kind of.The operation principle of similar Fig. 2 of operation principle of Fig. 3 (a), Fig. 3 (b), Fig. 3 (c) and Fig. 3 (d) is so omit its detailed description at this.

Please refer to Fig. 4.Fig. 4 is that the circuit of one embodiment of the invention is realized figure.In this embodiment, adopt Gilbert frequency mixer (Gilbert Mixer) to realize that the frequency mixer of other pattern is also applicable to the present invention certainly.Wherein, can be by setting LO1 (+)=f _o, LO1 (-)=-f _o, LO2 (+)=3f _o, LO2 (-)=-3f _o, LO3 (+)=5f _o, LO3 (-)=-5f _o, LO4 (+)=7f _oAnd LO4 (-)=-7f _oRealize Fig. 2, Fig. 3 (a) and the represented function of Fig. 3 (b).Because the Gilbert frequency mixer is a technology well known to those skilled in the art, its description of Therefore, omited.

Please refer to Fig. 5 again.Fig. 5 is that the circuit of another embodiment of Fig. 2, Fig. 3 (a) and Fig. 3 (b) is realized figure, and it adopts single-ended mixer (Single-ended Mixer) to realize; Wherein, can be by setting LO1 (+)=f _o, LO1 (-)=-f _o, LO2 (+)=3f _o, LO2 (-)=-3f _o, LO3 (+)=5f _o, LO3 (-)=-5f _o, LO4 (+)=7f _oAnd LO4 (-)=-7f _oRealize the function that Fig. 2, Fig. 3 (a) and Fig. 3 (b) will represent.Since the technology that single-ended mixer is well known to those skilled in the art, its description of Therefore, omited.

Please refer to Fig. 6 again.Fig. 6 is that the circuit of the embodiment of Fig. 2, Fig. 3 (c) and Fig. 3 (d) is realized figure, and it also adopts the Gilbert frequency mixer to realize; Wherein, can be by setting LO1 (+)=f _o, LO1 (-)=-f _o, LO2 (+)=3f _o, LO2 (-)=-3f _o, LO3 (+)=5f _o, LO3 (-)=-5f _o, LO4 (+)=7f _oAnd LO4 (-)=-7f _oRealize the function that Fig. 2, Fig. 3 (c) and Fig. 3 (d) will represent.

In addition, by Fig. 4, Fig. 5, Fig. 6 as can be known, an embodiment of the totalling unit of Fig. 2 and Fig. 3 (a)-3 (d) can be a node.

In the application of reality, if when the signal strength signal intensity of harmonic term is very little, then corresponding harmonic wave is eliminated circuit (gain unit and mixing unit) and can be omitted; For example: since very little than the signal strength signal intensity of the harmonic term of high order, so eliminating circuit, can omit the harmonic wave of quintuple harmonics item and the harmonic term more than five times, and in other words, the harmonic wave that only keeps the triple-frequency harmonics item is eliminated circuit; Certainly, if more accurate signal is handled for late-class circuit, the harmonic wave that then can keep triple-frequency harmonics item and quintuple harmonics item is eliminated circuit.

The above is preferred embodiment of the present invention only, is not to be used for limiting scope of the invention process, and all equalizations of being done according to the described shape of claim of the present invention, structure, feature and spirit change and modify, and all should be included within the claim of the present invention.

Claims (8)

1. mixer device, in order to carry out mixing, this mixer device comprises:

One first mixting circuit, it is in order to receiving an input signal and one first clock signal, and in order to export a mixed frequency signal, wherein this mixed frequency signal includes the N rd harmonic signal, and N is a positive integer;

One harmonic wave is eliminated circuit, and it is in order to receiving a second clock signal, and in order to export a harmonic wave erasure signal, wherein, and one of at least corresponding in this harmonic wave erasure signal and the described N rd harmonic signal; And

One adds way circuit, in order to receiving this mixed frequency signal and this harmonic wave erasure signal, and this mixed frequency signal and this harmonic wave erasure signal are added up, and in order to producing an output signal,

Wherein, when this harmonic wave erasure signal was corresponding with this N rd harmonic signal, then to eliminate a yield value of circuit be the 1/N of a yield value of this first mixting circuit for this harmonic wave, and this second clock signal N frequency multiplication that is this first clock signal.

2. mixer device as claimed in claim 1, wherein this harmonic wave elimination circuit comprises:

One gain unit is in order to change the gain of this input signal according to a yield value, to export a gain signal; And

One mixing unit is in order to carry out mixing with this gain signal and this second clock signal, to export this harmonic wave erasure signal.

3. mixer device as claimed in claim 1, wherein this harmonic wave elimination circuit comprises:

One mixing unit is in order to carry out mixing with this input signal and this second clock signal, to export one second mixed frequency signal; And

One gain unit is in order to change the gain of this second mixed frequency signal according to a yield value, to export this harmonic wave erasure signal.

4. as claim 2 or 3 described mixer devices, wherein this to add way circuit be a node.

5. frequency mixing method comprises:

Receive an input signal and one first clock signal;

Carry out mixing according to this input signal and this first clock signal, to export a mixed frequency signal, wherein this mixed frequency signal includes the N rd harmonic signal, and N is a positive integer;

Produce a harmonic wave erasure signal, wherein one of at least corresponding in this harmonic wave erasure signal and the described N rd harmonic signal; And

This mixed frequency signal and this harmonic wave erasure signal are added up, and in order to producing an output signal,

When wherein this harmonic wave erasure signal is corresponding with this N rd harmonic signal, be 1/N then corresponding to a yield value of this N rd harmonic signal corresponding to a yield value of this harmonic wave erasure signal, and this second clock signal N frequency multiplication that is this first clock signal.

6. method as claimed in claim 5, wherein the step of this generation harmonic wave erasure signal also comprises:

Carry out mixing according to this input signal and a second clock signal, to export this harmonic wave erasure signal.

7. method as claimed in claim 5, wherein the step of this generation harmonic wave erasure signal also comprises:

Foundation one yield value is changed the gain of this input signal, to export a gain signal; And

This gain signal and a second clock signal are carried out mixing, to export this harmonic wave erasure signal.

8. method as claimed in claim 5, wherein the step of this generation harmonic wave erasure signal also comprises:

This input signal and a second clock signal are carried out mixing, to export one second mixed frequency signal; And

Foundation one yield value is changed the gain of this second mixed frequency signal, to export this harmonic wave erasure signal.

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