CN102222246B - Carrier inhibiting method for radio frequency identification reader-writer and radio frequency device - Google Patents
Carrier inhibiting method for radio frequency identification reader-writer and radio frequency device Download PDFInfo
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- CN102222246B CN102222246B CN201110174689.6A CN201110174689A CN102222246B CN 102222246 B CN102222246 B CN 102222246B CN 201110174689 A CN201110174689 A CN 201110174689A CN 102222246 B CN102222246 B CN 102222246B
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Abstract
The invention relates to a carrier inhibiting method for a radio frequency identification reader-writer, which comprises the following steps of: processing a received signal to obtain two paths of orthogonal baseband signals, obtaining an initial phase valve and an amplitude valve of a cancelling signal by use of two paths of orthogonal baseband signals; carrying out iterative operation on the initial phase value of the cancelling signal to obtain a target phase valve of the cancelling signal; and generating the cancelling signal, and overlapping the cancelling signal to the received signal after modulation. The invention also relates to a radio frequency device of the radio frequency identification reader-writer. By implementing the carrier inhibiting method for the radio frequency identification reader-writer and the radio frequency device in the invention, the beneficial effect that the carrier of the reader-writer per se in a receiving channel can be effectively cancelled is achieved.
Description
Technical field
The present invention relates to field of radio frequency identification, more particularly, relate to a kind of carrier wave inhibition method and radio-frequency unit of radio-frequency identification reader/writer.
Background technology
Radio-frequency (RF) identification is a kind of recognition technology of utilizing spatial electromagnetic wave to carry out exchanges data.Radio-frequency recognition system is mainly comprised of reader and label.Reader carrys out obtaining information by identification label.According to the difference of tag class, decipherment distance is also different.Existing label is divided into two kinds of active label and passive labels.Wherein passive label is used widely because cost is low and volume is little.But because passive label is that carrier wave by reflection modulation read write line communicates, thereby be easily subject to many interference, these interference comprise: the transmitted signal of read write line, it is phase noise for reception carrier, easily and echo obscure; The non-tag reflection carrier wave that read write line receives; The leakage carrier wave of read write line inside.These interference are all to have the same audio-frequency noise of out of phase with read write line self carrier wave for read write line.If these noises directly amplify after entering receiving cable, will surpass the dynamic range of receiver, receiving cable is got clogged, cannot correctly solve echo information.Therefore, elimination as much as possible or counteracting read write line self carrier signal are the comparatively key measures that reaches peak response; But, in prior art, when receiving, comparatively effectively do not eliminate or offset the method for read write line self carrier wave.
Summary of the invention
The technical problem to be solved in the present invention is, the above-mentioned method defect of comparatively effectively not eliminating or offset read write line self carrier wave when receiving for prior art, provides a kind of method and the radio-frequency unit that can offset largely read write line self carrier wave.
The technical solution adopted for the present invention to solve the technical problems is: construct a kind of carrier wave inhibition method of radio-frequency identification reader/writer, comprise the steps:
A) process to the received signal, obtain the baseband signal of two-way quadrature;
B) utilize the baseband signal of described two-way quadrature to obtain prima facies place value and the range value of offseting signal;
C) the prima facies place value of described offseting signal is carried out to interative computation, obtain the target phase value of described offseting signal;
D) generate offseting signal, and on the signal receiving described in it is added to after ovennodulation.
In the carrier wave inhibition method of a kind of radio-frequency identification reader/writer of the present invention, described steps A) further comprise the steps:
A1) the described signal receiving is carried out to pre-amplification, and carry out quadrature demodulation, obtain two-way quadrature intermediate-freuqncy signal;
A2) two-way quadrature intermediate-freuqncy signal is carried out respectively to low-pass filtering and analog to digital conversion, obtain the baseband signal of two-way quadrature.
In the carrier wave inhibition method of a kind of radio-frequency identification reader/writer of the present invention, described step B) further comprise the steps:
B1) according to formula
obtain the initial amplitude of offseting signal;
B2) according to formula
obtain the initial phase of offseting signal;
Wherein, A is the initial amplitude value of described offseting signal,
the prima facies place value of described offseting signal, S
qthe range value of in the baseband signal of described two quadratures, S
iit is another range value in the baseband signal of described two quadratures.
In the carrier wave inhibition method of a kind of radio-frequency identification reader/writer of the present invention, described step C) further comprise the steps:
C1) on the basis of the prima facies place value of the offseting signal obtaining respectively to its increase with reduce a skew phase value θ who sets, the phase value that is increased and reduce;
C2) utilize the phase value of the phase value of described initial amplitude and increase, described initial amplitude and minimizing to obtain respectively the first iteration offseting signal and secondary iteration offseting signal;
C3) the described input signal of respectively described the first iteration offseting signal and secondary iteration offseting signal being modulated and be added to, and while recording respectively described the first iteration offseting signal of stack and secondary iteration offseting signal near power local frequency and;
C4) more described power and size, and according to the direction of phase adjustment of power and less iteration offseting signal by described initial phase
with the pi/2 that adds deduct
istep-length regulate; Wherein, i is iterations;
C5) complete iteration? in this way, exit interative computation, the phase value after regulating is as the target phase value of described offseting signal
otherwise, by the phase value after described adjusting
or
as initial phase, return to step C1).
In the carrier wave inhibition method of a kind of radio-frequency identification reader/writer of the present invention, described step C5), in, complete the condition interative computation number of times that be prior setting or that stipulated by host computer of iteration.
In the carrier wave inhibition method of a kind of radio-frequency identification reader/writer of the present invention, described step D) further comprise the steps:
D1) according to the initial amplitude value obtaining and prima facies place value, generate offseting signal, described offseting signal is the baseband signal of two quadratures, is respectively
and
D2) baseband signal of described two quadratures that obtain is carried out to orthogonal modulation, obtain offseting signal
The present invention has also disclosed a kind of radio-frequency unit of realizing the carrier wave inhibition method of above-mentioned radio-frequency (RF) Reader, comprise the sendaisle and the receiving cable that by loop coupling device, link together, described receiving cable comprises for the signal receiving being converted to the digital orthogonal baseband signal formation module of two base band orthogonal signal, the data decode module of label transmission data will be obtained in described digital orthogonal baseband signal output signal, in described digital orthogonal baseband signal output signal, obtain the initial amplitude value of offseting signal and the initial parameter of prima facies place value obtains module, described initial parameter is obtained to prima facies place value in module output is carried out iteration and the target phase value that obtains target phase value obtains module, utilize described initial amplitude value and target phase value generating orthogonal base band offseting signal offseting signal generation module and the base band offseting signal of described quadrature is modulated to offseting signal and outputs to the offseting signal modulation module of merging into the signal receiving in combiner with described receiving cable input signal.
In radio-frequency unit of the present invention, described initial parameter obtains two base band orthogonal signal that module further comprises that the signal that receives described in acceptance converts to, and according to
the initial amplitude that obtains offseting signal initial amplitude obtain unit and according to
the initial phase that obtains offseting signal initial phase is obtained unit; Wherein A is the initial amplitude value of described offseting signal,
the prima facies place value of described offseting signal, S
qthe range value of in the baseband signal of described two quadratures, S
iit is another range value in the baseband signal of described two quadratures.
In radio-frequency unit of the present invention, described target phase value obtains module and comprises for increase or deduct the skew phase unit of the skew phase value θ of setting in described prima facies place value, is that its phase place of initial amplitude is respectively respectively to its amplitude
with
the first iteration offseting signal and secondary iteration offseting signal modulation after mix with receiving cable input signal after near the power local frequency of described radio-frequency unit and power and the comparing unit comparing, according to pi/2
istep-length regulate the initial phase fine-adjusting unit of described initial phase and calculate iterations and judge the iteration judging unit whether iteration completes, wherein i is iterations.
In radio-frequency unit of the present invention, described digital orthogonal baseband signal formation module and described offseting signal modulation module comprise respectively the first quadrature local oscillations source and the second quadrature local oscillations source of the local oscillated signal of output orthogonal, and the oscillator signal in described first, second quadrature local oscillations source is coupled and is obtained by the local oscillation signal of described sendaisle.
Implement carrier wave inhibition method and the radio-frequency unit of radio-frequency identification reader/writer of the present invention, there is following beneficial effect: due to the baseband signal that is quadrature by the signal decomposition receiving, and from wherein obtaining initial amplitude and the prima facies place value of offseting signal, again prima facies place value is adjusted, obtained target phase value; According to initial amplitude and target phase value, form offseting signal again, offset the carrier signal in receiving cable.Therefore, can more efficiently offset read write line self carrier wave in receiving cable.
Accompanying drawing explanation
Fig. 1 is the process flow diagram of method in the carrier wave inhibition method of radio-frequency identification reader/writer of the present invention and radio-frequency unit embodiment;
Fig. 2 is the process flow diagram of described embodiment initial phase interative computation;
Fig. 3 is the structural representation of radio-frequency unit in described embodiment.
Embodiment
Below in conjunction with accompanying drawing, embodiments of the present invention is further illustrated.
As shown in Figure 1, in the carrier wave inhibition method and radio-frequency unit embodiment of radio-frequency identification reader/writer of the present invention, its carrier wave inhibition scheme comprises the steps:
Step S11 carries out pre-amplification, rectification to the received signal, obtain two-way quadrature intermediate-freuqncy signal: in this step, the signal that enters receiving cable by antenna, circulator passes through combiner, and after pre-amplification, be divided into two-way, adopt respectively the local oscillation signal rectification of its phase phasic difference 90 degree, obtain the intermediate-freuqncy signal of two-way quadrature.During beginning, on another input end of combiner, also there is no offseting signal output.If another input end has offseting signal input in combiner, so, in this step, processing be exactly by combiner superpose mixed input signal and offseting signal, the signal receiving.In the present embodiment, above-mentioned local oscillation signal is by it being entered to the local oscillation signal of the quadrature obtaining after horizontal phasing control after the local oscillator coupling to sending.
Step S12 to the filtering of two-way quadrature intermediate-freuqncy signal, analog to digital conversion, obtains digital orthogonal baseband signal respectively: in this step, respectively the two-way intermediate-freuqncy signal obtaining in step is above carried out to low pass filtered and involve analog to digital conversion, obtain the baseband signal of two-way quadrature.Described baseband signal is digital signal.
Step S13 obtains initial amplitude value: in this step, and according to formula
obtain the initial amplitude of offseting signal;
Step S14 obtains prima facies place value: in this step, and according to formula
obtain the initial phase of offseting signal; In this step and step S13, A is the initial amplitude value of described offseting signal,
the prima facies place value of described offseting signal, S
qthe range value of in the baseband signal of described two quadratures, S
iit is another range value in the baseband signal of described two quadratures.
Step S15, to prima facies place value iteration, obtains target phase value: in this step, the prima facies place value obtaining in step S14 is carried out to iteration, obtain target phase value
its detailed process describes in detail after a while.
Step S16 obtains two-way base band offseting signal according to initial amplitude value and target phase value: in this step, according to the initial amplitude value obtaining in above-mentioned steps and target phase value, generate two-way base band offseting signal, be respectively
and
Step S17 orthogonal modulation two-way base band offseting signal, obtain offseting signal and mix the rear signal as receiving with reception signal: in this step, respectively the baseband signal of obtain two quadratures is carried out to digital-to-analog conversion, and by the local oscillation signal of phase phasic difference 90 degree, it is carried out to orthogonal modulation respectively, obtain offseting signal
this signal with mix the anti-phase same width of reception signal approximation of revealing carrier wave, it is fed back to receiving cable by combiner, can reach and eliminate the effect that carrier wave leakage is disturbed.In the present embodiment, above-mentioned local oscillation signal is by it being entered to the local oscillation signal of the quadrature obtaining after horizontal phasing control after the local oscillator coupling to sending.
In above-mentioned steps, step S11, S12, for processing to the received signal, obtain the baseband signal of two-way quadrature; Step S13, S14 utilize the baseband signal of described two-way quadrature to obtain prima facies place value and the range value of offseting signal; Step S15, for the prima facies place value of described offseting signal is carried out to interative computation, obtains the target phase value of described offseting signal; Step S16, S17 are for generating offseting signal, and the signal to obtain receiving on reception signal that it is added to after ovennodulation.
In the present embodiment, above-describedly by iteration, initial phase is adjusted into target phase value
step as shown in Figure 2, its step is as follows:
Step S301 determines iteration initial phase, and this phase place is step S14 gained initial phase
Step S302 and step S304 add and subtract respectively skew phase place, for generating two comparative quantities, in phase place
upper plus-minus θ obtains two paths of signals.That is to say, on the basis of the prima facies place value of the offseting signal obtaining in step S302, step S304 respectively to its increase with reduce a skew phase value θ who sets, the phase value that is increased and reduce; Utilize the phase value of phase value, initial amplitude and the minimizing of initial amplitude and increase to obtain respectively the first iteration offseting signal and secondary iteration offseting signal; It is worth mentioning that, two comparative quantities in step S302 and step S304, are not produced simultaneously, but successively produce, for example, the phase value that can first produce an increase is measured as a comparison, exported, and by step S303 obtain the power corresponding with this comparative quantity and; Produce again one and reduce phase value as another one comparative quantity, by step S305 obtain power that another one comparative quantity is corresponding and; Perform step again afterwards S306.Although the setting of this comparative quantity and power and acquisition mode are sacrificed to some extent in timeliness,, the structure of its power and Acquisition Circuit is relative simple, and cost is lower.That is to say step S302 and step S303 Wei Yi road; Step S304 and step S305 are an other road, and this two-way is not to carry out simultaneously, but successively carry out.
Step S303 and step S305 bring into respectively offset and calculate corresponding power and, two paths of signals is fed back to and is received in signal, gather near power local frequency and.In this step, the described input signal of respectively the first iteration offseting signal and secondary iteration offseting signal being modulated and be added to, and while recording respectively stack the first iteration offseting signal and secondary iteration offseting signal near power local frequency and.
Step S306 relatively two power and, and according to the direction of phase adjustment of power and less iteration offseting signal by described initial phase
with the pi/2 that adds deduct
istep-length regulate; Wherein, i is iterations;
Step S307 and step S308 produce respectively iterative phase, according to comparative result, select iteration direction to carry out next iteration.In step S307 and step S308, in an iterative process, only can carry out in these two steps, the step being performed determines according to above-mentioned power and comparative result; If power and 1 is less than power and 2 (referring to Fig. 2), perform step S307; Otherwise execution step S308.In these two steps, also need respectively to have judged whether iteration? in this way, exit interative computation, the phase value after regulating is as the target phase value of described offseting signal
otherwise, by the phase value after described adjusting
or
as initial phase, start iteration again.
The result that above-mentioned steps S301-S308 carries out, is to obtain a target phase comparatively accurately, eliminates better the carrier wave receiving in signal.
In addition, in the present embodiment, also relate to a kind of radio-frequency unit of realizing above-mentioned carrier wave inhibition method, the structure of this radio-frequency unit as shown in Figure 3, comprise: antenna 101, circulator 102, combiner 103, power amplifier 104, low noise amplifier 105, variable gain amplifier 106, multiplier 107, directional coupler 108, phase-splitter 109, digital to analog converter 110, local oscillator 111, low-pass filter 112, analog to digital converter 113, transmitted signal module 114, data decode module 115, initial parameter obtains module 116, target phase obtains module 117, offseting signal forms module 118 and received power detection module 119.Wherein, power amplifier 104, multiplier 107, digital to analog converter 110, transmitted signal module 114 and local oscillator 111 form sendaisle; Miscellaneous part except antenna 101 and circulator 102 is receiving cable, and referring to Fig. 3, being wherein connected to the part that data decode module 115, initial parameter obtain between module 116 and low noise amplifier 105 is that digital orthogonal baseband signal forms module; The part being connected between offseting signal formation module 118 and variable gain amplifier 106 is offseting signal modulation module; Digital orthogonal baseband signal forms module the signal receiving (comprising independent reception signal and the reception signal that has mixed offseting signal) is converted to two base band orthogonal signal; Data decode module 115 is formed and in module output signal, is obtained label transmission data by described digital orthogonal baseband signal; Initial parameter obtains module 116 and forms by described digital orthogonal baseband signal initial amplitude value and the prima facies place value that obtains offseting signal in module output signal; Target phase value obtains the prima facies place value that 117 pairs of initial parameters of module obtain in module 116 output and carries out iteration and obtain target phase value; Offseting signal generation module 118 utilizes the base band offseting signal of initial amplitude value and target phase value (being the prima facies place value after adjusting in above-mentioned iterative process) generating orthogonal; Offseting signal modulation module is modulated to offseting signal by the base band offseting signal of quadrature and outputs in combiner 103 merges into above-mentioned receiving cable input signal the signal receiving; Near the power of received power detection module 119 having mixed the reception signal intermediate frequency of offseting signal and information output to target phase value and obtain module 117 as the foundation of judgement iteration travel direction.
In the present embodiment, initial parameter obtains module 116 and further comprises that initial amplitude value obtains unit and prima facies place value obtains unit (not shown); Wherein, initial amplitude obtains unit described digital orthogonal baseband signal is formed to two base band orthogonal signal that module converts becomes, according to
obtain offseting signal initial amplitude; Initial phase obtain unit according to
obtain offseting signal initial phase; Wherein A is the initial amplitude value of offseting signal,
the prima facies place value of offseting signal, S
qthe range value of in the baseband signal of two quadratures, S
iit is another range value in the baseband signal of two quadratures.And target phase value obtain module 117 comprise skew phase unit, power and comparing unit, initial phase fine-adjusting unit and iteration judging unit (not shown); Wherein, skew phase unit for increasing or deduct the skew phase value θ of setting in described prima facies place value; Power and comparing unit are that its phase place of initial amplitude is respectively in its amplitude
with
the first iteration offseting signal and after secondary iteration offseting signal mixes with receiving cable input signal after modulation, respectively through received power detection module 119 obtain near the power local frequency of described radio-frequency unit with, and both are compared; Initial phase fine-adjusting unit is according to pi/2
istep-length regulate initial phase, wherein i is iterations; Iteration judging unit calculates iterations and judges whether iteration completes; In the present embodiment, iterations i inputs by the host computer of artificial or this reader in advance.
Wherein, transmitted signal module 114, data decode module 115, initial parameter obtains module 116, and target phase obtains module 117 and offseting signal formation module 118 belongs to digital signal processing parts, and remaining part is analog signal processing component.
In the present embodiment, signal flow is as follows: first, transmitted signal module 114 is sent baseband signal into digital to analog converter 110, digital signal is converted to simulating signal, send into multiplier 107, after the carrier signal modulation of sending through local oscillator 111, send into power amplifier 104, after amplification, send into circulator 102 and antenna 101 transmittings.
Receive signal and enter receiving cable by antenna 101 and circulator 102, first pass through combiner 103, then after amplifying, low noise amplifier 105 sends into quadrature demodulation passage I, in Q (being that above-mentioned digital orthogonal baseband signal forms in module), wherein 0 ° of phase-shift signal of I road signal and local oscillator 111 multiplies each other, demodulation after low-pass filter 112, sends into and in analog to digital converter 113, converts digital signal to and enter data decode module 115; 90 ° of phase-shift signals of Q road signal and local oscillator 111 multiply each other, and remainder is with I road.
Owing to receiving signal and transmitted signal, share an antenna, and separated through circulator, the isolation of circulator has determined to be mixed with in reception signal leakage carrier wave, thereby this device has designed carrier cancellation loop, described carrier cancellation loop comprises: the signal after digitizing is obtained module 116 through initial parameter and calculated after counteracting phase place and amplitude, sending into target phase value obtains module 117 and carries out phase place and further approach, then send into offseting signal modulation module, after digital-to-analog conversion and orthogonal modulation, send into variable gain amplifier 106 and carry out amplitude correction, finally generate carrier cancelled signal and send into combiner 103.
The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (6)
1. the carrier wave inhibition method of a radio-frequency identification reader/writer, is characterized in that, comprises the steps:
A) process to the received signal, obtain the baseband signal of two-way quadrature;
B) utilize the baseband signal of described two-way quadrature to obtain prima facies place value and the range value of offseting signal;
C) the prima facies place value of described offseting signal is carried out to interative computation, obtain the target phase value of described offseting signal;
D) generate offseting signal, and on the signal receiving described in it is added to after ovennodulation; Described step B) further comprise the steps:
B1) according to formula
obtain the initial amplitude of offseting signal;
B2) according to formula
obtain the initial phase of offseting signal;
Wherein, A is the initial amplitude value of described offseting signal,
the prima facies place value of described offseting signal, S
qthe range value on baseband signal Zhong mono-tunnel of described two-way quadrature, S
iit is the range value on another road in the baseband signal of described two-way quadrature;
Described step C) further comprise the steps:
C1) on the basis of the prima facies place value of the offseting signal obtaining respectively to its increase with reduce a skew phase value θ who sets, the phase value that is increased and reduce;
C2) utilize the phase value of the phase value of described initial amplitude and increase, described initial amplitude and minimizing to obtain respectively the first iteration offseting signal and secondary iteration offseting signal;
C3) input signal of respectively described the first iteration offseting signal and secondary iteration offseting signal being modulated and be added to, and while recording respectively described the first iteration offseting signal of stack and secondary iteration offseting signal near power local frequency and;
C4) more described power and size, and according to power and the direction that reduces by described initial phase
with the pi/2 that adds deduct
istep-length regulate; Wherein, i is iterations;
C5) complete iteration? in this way, exit interative computation, the phase value after regulating is as the target phase value of described offseting signal
otherwise, by the phase value after described adjusting
or
as initial phase, return to step C1).
2. the carrier wave inhibition method of radio-frequency identification reader/writer according to claim 1, is characterized in that, described steps A) further comprise the steps:
A1) the described signal receiving is carried out to pre-amplification, and carry out quadrature demodulation, obtain two-way quadrature intermediate-freuqncy signal;
A2) two-way quadrature intermediate-freuqncy signal is carried out respectively to low-pass filtering and analog to digital conversion, obtain the baseband signal of two-way quadrature.
3. the carrier wave inhibition method of radio-frequency identification reader/writer according to claim 1, is characterized in that, described step C5) in, the condition interative computation number of times that be prior setting or that stipulated by host computer of iteration completed.
4. according to the carrier wave inhibition method of the radio-frequency identification reader/writer described in any one in claim 1-3, it is characterized in that described step D) further comprise the steps:
D1) according to the initial amplitude value obtaining and prima facies place value, generate offseting signal, described offseting signal is the baseband signal of two quadratures, is respectively
and
D2) baseband signal of described two quadratures that obtain is carried out to orthogonal modulation, obtain offseting signal
5. the radio-frequency unit of a radio-frequency identification reader/writer, comprise the sendaisle and the receiving cable that by loop coupling device, link together, it is characterized in that, described receiving cable comprises for the signal receiving being converted to the digital orthogonal baseband signal formation module of two base band orthogonal signal, the data decode module of label transmission data will be obtained in described digital orthogonal baseband signal output signal, in described digital orthogonal baseband signal output signal, obtain the initial amplitude value of offseting signal and the initial parameter of prima facies place value obtains module, described initial parameter is obtained to prima facies place value in module output is carried out iteration and the target phase value that obtains target phase value obtains module, utilize described initial amplitude value and target phase value generating orthogonal base band offseting signal offseting signal generation module and the base band offseting signal of described quadrature is modulated to offseting signal and outputs to the offseting signal modulation module of merging into the signal receiving in combiner with described receiving cable input signal,
Described initial parameter obtains two base band orthogonal signal that module further comprises that the signal that receives described in acceptance converts to, and according to
the initial amplitude that obtains offseting signal initial amplitude obtain unit and according to
the initial phase that obtains offseting signal initial phase is obtained unit; Wherein A is the initial amplitude value of described offseting signal,
the prima facies place value of described offseting signal, S
qthe range value on baseband signal Zhong mono-tunnel of described two-way quadrature, S
iit is the range value on another road in the baseband signal of described two-way quadrature;
Described target phase value obtains module and comprises for increase or deduct the skew phase unit of the skew phase value θ of setting in described prima facies place value, is that its phase place of initial amplitude is respectively respectively to its amplitude
with
the first iteration offseting signal and secondary iteration offseting signal modulation after mix with receiving cable input signal after near the power local frequency of described radio-frequency unit and power and the comparing unit comparing, according to pi/2
istep-length regulate the initial phase fine-adjusting unit of described initial phase and calculate iterations and judge the iteration judging unit whether iteration completes; Wherein i is iterations.
6. the radio-frequency unit of radio-frequency identification reader/writer according to claim 5, it is characterized in that, described digital orthogonal baseband signal formation module and described offseting signal modulation module comprise respectively the first quadrature local oscillations source and the second quadrature local oscillations source of the local oscillated signal of output orthogonal, and the oscillator signal in described first, second quadrature local oscillations source is coupled and is obtained by the local oscillation signal of described sendaisle.
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| JP3548148B2 (en) * | 2001-09-27 | 2004-07-28 | 松下電器産業株式会社 | OFDM transmission apparatus and OFDM transmission method |
| JP4341418B2 (en) * | 2004-01-30 | 2009-10-07 | 日本電気株式会社 | Quadrature modulator adjustment apparatus and adjustment method, communication apparatus and program |
| CN101483632B (en) * | 2009-01-22 | 2011-03-30 | 清华大学 | Phase noise correcting method using out-of-band pilot in OFDM system |
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2011
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