CN102291154B - Polar coordinate transmitter - Google Patents
Polar coordinate transmitter Download PDFInfo
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- CN102291154B CN102291154B CN201110285043.5A CN201110285043A CN102291154B CN 102291154 B CN102291154 B CN 102291154B CN 201110285043 A CN201110285043 A CN 201110285043A CN 102291154 B CN102291154 B CN 102291154B
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Abstract
The invention provides a polar coordinate transmitter, which can meet the requirement of high speed rate at a low-speed clock frequency, i.e., compensate for integer time delay and fraction time delay under the condition of not increasing the sampling rate. The polar coordinate transmitter comprises a polar coordinate generating unit, an amplitude modulating unit, a phase modulating unit, a switch power amplifying unit, a time delay estimating unit and a variable fraction time delay filter, wherein the time delay estimating unit is used for estimating integer time delays of a phase channel and an amplitude channel on a time domain respectively, compensating for the integer time delays, estimating fraction time delays of the phase channel and the amplitude channel on a frequency domain respectively, adding an integer time delay error and a fraction time delay error between the phase channel and the amplitude channel to obtain a time delay error, and setting the variable fraction time delay filter according to the obtained time delay error; and the variable fraction time delay filter is used for performing time delay on a signal input into the phase channel and compensating for the time delay error between the phase channel and the amplitude channel.
Description
Technical field
The present invention relates to wireless communication technology, particularly the delay compensation technology of transmitter.
Background technology
Polar coordinate transmitter combines power supply modulation technique and Switch power amplifier technology.Polar coordinate transmitter comprises polar coordinates generation unit, amplitude modulation unit, phase modulation unit, switch power amplifying unit, polar coordinates generation unit, for the digital amplitude information of generation is sent to amplitude modulation unit, the digital phase information of generation is sent to phase modulation unit; Phase modulation unit, for digital phase information is converted to analog signal, generates the phase modulated signal of radio frequency constant envelope and exports the input of switch power amplifying unit to through phase-modulation; Amplitude modulation unit, for digital amplitude information is converted to analog signal, the power supply modulation signal after power supply modulation exports the control end of switch power amplifying unit to; Switch power amplifying unit, for carrying out being emitted to spatial domain after power amplification to input signal.Polar coordinate transmitter separates the signal into range signal and phase signal, and amplitude channels adopts power supply modulation technique to carry out envelope-tracking, and phase path adopts Switch power amplifier to amplify after being modulated to radio frequency.After width is separated, because phase path adopts constant envelope signal, thereby the efficiency of complete machine obtains significantly lifting.Amplitude channels adopts signal envelope, with respect to phase path, has compared with long time delay.In polar coordinate transmitter, phase path is not mated and will be caused nonlinear distortion with the time delay between amplitude channels, and the performance of final transmitter is exerted an influence.
The time delay of two passages is not mated can decay ACLR (Adjacent Channel Leakage Ratio, adjacent channel leakage ratio) and EVM (Error Vector Magnitude, Error Vector Magnitude).For LTE (Long Term Evolution, Long Term Evolution) signal is example, according to current standard, should be less than-45dBc of side channel ACLR, 16QAM (Quadrature Amplitude Modulation, quadrature amplitude modulation) modulation EVM_rms (Error Vector Magnitude Root Mean Square, the root mean square of Error Vector Magnitude) should be less than 12.5%, 64QAM modulation EVM_rms should be less than 8%, QPSK (Quadrature Phase Shift Keying, Quadrature Phase Shift Keying) modulation EVM_rms should be less than 17.5%.When two interchannel time delays, do not mate and reach 10%Ts when (sampling period), ACLR is discontented with sufficient index request, as shown in Figure 1.Be that polar coordinate transmitter time delay error not only comprises integer time delay error, also comprise fractional delay, two interchannel time delay errors should be less than 10%Ts.Delay time error, requiring fractional delay is the hundredths in sampling period.If adopt different test signals, require standard to have difference, desired fractional delay least unit has tiny difference, but two interchannel time delay errors all can include fractional delay error.Integer time delay error refers to that the time of delay error equals the integral multiple in sampling period, and integer time delay is easy to realize, and only needs a time delay integer sampling period.But fractional delay, need to carry out interpolation processing or improve sample rate, processes complexity high, has greatly increased the complexity of correcting time delay error.
Summary of the invention
The present invention wants technical solution problem to be, a kind of two-forty requirement that realizes under low-speed clock frequency is provided, and, in the situation that not improving sample rate, compensates the polar coordinate transmitter of integer time delay and fractional delay.
The present invention solves the problems of the technologies described above adopted technical scheme to be, polar coordinate transmitter comprises polar coordinates generation unit, amplitude modulation unit, phase modulation unit, switch power amplifying unit, it is characterized in that, also comprise time delay estimation unit, variable fractional time delay filter, an output of described polar coordinates generation unit connects the input of amplitude modulation unit, another output of polar coordinates generation unit connects the input of phase modulation unit through variable fractional time delay filter, the control end of the output connecting valve power amplification unit of amplitude modulation unit, the input of the output connecting valve power amplification unit of phase modulation unit, amplitude modulation unit, phase modulation unit connect respectively the input of time delay estimation unit, and the output of time delay estimation unit is connected with the control end of variable fractional time delay filter,
Described time delay estimation unit, for estimate respectively the integer time delay of phase path and amplitude channels in time domain, carries out, after integer delay compensation, estimating respectively the fractional delay of phase path and amplitude channels on frequency domain; Finally the integer time delay error between phase path and amplitude channels and the addition of fractional delay error are obtained to time delay error, and according to the time delay error obtaining, variable fractional time delay filter is set;
Described variable fractional time delay filter, for the signal of input phase passage is carried out to time delay, carries out the time delay error compensation between phase path and amplitude channels.
The invention has the beneficial effects as follows, by amplitude channels and phase path time delay are estimated, in phase path, add variable fractional time delay filter to carry out delay compensation error, not in the situation that changing low-speed clock frequency, realize two-forty delay compensation, solution, because time delay is not mated the deterioration problem of brought polar coordinates performance, really realizes the high efficiency of signal and amplifies.
Accompanying drawing explanation
Fig. 1 be take LTE as example, and amplitude and phase path time delay are not mated the impact on ACLR;
Fig. 2 polar coordinate transmitter structural representation of the present invention;
Fig. 3 is embodiment schematic diagram;
Fig. 4 is the schematic diagram that different filter coefficients can be realized different fractional delays.
Embodiment
Polar coordinate transmitter comprises polar coordinates generation unit 10 as shown in Figure 2, amplitude modulation unit 20, phase modulation unit 30, time delay estimation unit 40, switch power amplifying unit 50, variable fractional time delay filter 60, an output of polar coordinates generation unit 10 connects the input of amplitude modulation unit 20, another output of polar coordinates generation unit 10 connects the input of phase modulation unit 30 through variable fractional time delay filter 60, the control end of the output connecting valve power amplification unit 50 of amplitude modulation unit 20, the input of the output connecting valve power amplification unit 50 of phase modulation unit 30, amplitude modulation unit 20, phase modulation unit 30 connect respectively the input of time delay estimation unit 40, and the output of time delay estimation unit 40 is connected with the control end of variable fractional time delay filter 60.
Polar coordinates generation unit 10, generating digital amplitude information is sent to amplitude modulation unit 20, and the digital phase information of generation is sent to phase modulation unit 30;
Time delay estimation unit 40, in time domain, estimate respectively the integer time delay of phase path and amplitude channels, carry out after integer delay compensation, on frequency domain, estimate respectively the fractional delay of phase path and amplitude channels, integer time delay error between phase path and amplitude channels and fractional delay error are added and obtain time delay error, and according to the time delay error obtaining, fractional time delay filter 60 are set;
Fractional time delay filter 60, carries out the time delay error compensation between phase path and amplitude channels to the signal of input phase passage, exports the digital phase information after time delay error compensation to phase modulation unit 30;
Switch power amplifying unit 50, carries out being emitted to spatial domain after power amplification to input signal.
Embodiment
As shown in Figure 3, polar coordinates generation unit 10 comprises baseband signal generation unit 11, utmost point seat converting unit 12.The I of the generation of baseband signal generation unit 11, Q signal are sat converting unit 12 through the utmost point and are processed, and sit converting unit 12 I, Q signal are transformed into polar coordinates (ρ, θ signal) from cartesian coordinate through the utmost point, and ρ is digital amplitude information, and θ is digital phase information:
Switch power amplifying unit 50 comprises switch power amplifier 51, radio-frequency antenna 52.
Cartesian coordinate is carried out completely to polar conversion under numeric field, and amplitude channels and the time delay error between phase path that utmost point seat converting unit 12 produces can be ignored.In the situation that not considering variable fractional time delay filter 60, the digital signal of the two passages respectively digital to analog converter 21,31 by is separately converted to analog signal, and the time delay error that digital to analog converter 21,31 produces also can be ignored. Analog reconstruction filter 22,32, should there is identical physics realization, but in fact due to reasons such as power consumptions, make the time delay coupling inaccuracy of reconfigurable filter, the time delay error that reconfigurable filter 22,32 causes is generally less than 0.1%Ts (sampling period).Time delay error between amplitude channels and phase path is mainly to be caused by power supply modulator 23 and phase-modulator 33.The frequency of phase path is generally GHz, and with respect to the frequency MHz of amplitude channels, the time delay of phase-modulator 33 is less than power supply modulator 23, and the time delay of phase path is less than the time delay of amplitude channels.Therefore, need to add delay compensation error in phase path.Time delay error not only comprises integer time delay error, also comprises fractional delay error.The time delay estimation unit 40 of the present embodiment is estimated the time delay that time delay that in amplitude channels signal produces through reconfigurable filter 22 and power supply modulator 23 and signal in phase path produce through reconfigurable filter 32 and phase-modulator 33.Optionally, if do not considered the time delay of reconfigurable filter 22,32, time delay estimation unit 40 can only be estimated the time delay that signal produces through power supply modulator 23 in amplitude channels and the time delay that signal produces through phase-modulator 33 in phase path.
Integer time delay refers to that the time of delay equals the situation of the integral multiple in sampling period.Integer time delay is estimated to adopt related operation, in time domain, estimates.The signal of supposing to input reconfigurable filter 22 in amplitude channels is x
aM(n), the signal of power supply modulator 23 outputs is y
aM(n-d
aM).Time delay estimation unit 40 is by the data x collecting
aMand y (n)
aM(n-d
aM) carry out related operation and try to achieve maximum:
wherein " * " for asking conjugation, N is the number of signal sampling point, n is temporary variable.Corresponding d when the maximum of related operation
aMbe the integer time delay of amplitude channels.It should be noted that, the data starting point collecting here should be corresponding, and not so time delay calibration will comprise the error of instrument.In like manner, use related operation to try to achieve the integer time delay d of phase path
pM.
Obtaining integer time delay d
aMand d
pMafterwards, after time delay estimation unit 40 carries out the calibration of integer time delay by data, then the data of phase path and amplitude channels after the calibration of integer time delay are transformed into frequency domain.For two relevant broadband signals, the phase place of the Fourier transform of cross-correlation function is linear in band.
On frequency domain, try to achieve after prolonging calibration data x ' in amplitude channels
aMand y ' (n)
aM(n-d
aM) to be converted to be again and again X
aM(e
j ω) and
the maximum of the cross-correlation function on frequency domain:
wherein " * " for asking conjugation, corresponding d ' when maximum
aMbe the fractional delay of amplitude channels.In like manner, try to achieve the fractional delay d ' of phase path
pM;
The time delay error that time delay estimation unit 40 obtains between phase path and amplitude channels is integer time delay error (d
aM-d
pM) and fractional delay error (d '
aM-d '
pM) sum.
Time delay estimation unit 40 obtains after time delay error, carrys out the parameter of selective filter according to time delay error, as filter type and exponent number, coefficient.As shown in Figure 4, different filter coefficients can be realized different fractional delays.Realize variable fractional delay, only need to select different filter coefficients.Different coefficient sets (from system S0 to S10), can realize any fractional delay from 0 to 1.At same type filter, same integer time delay part, just fractional delay from 0 to 1 optional situation, the exponent number of filter is also fixed, and by selecting different coefficients, can realize the arbitrary value of fractional delay from 0 to 1.
Variable fractional time delay filter 60 can carry out integer time delay and fractional delay is processed, variable fractional time delay filter 60 comprises FIR (Finite Impulse Response, finite impulse response) filter and IIR (Infinite Impulse Response, wireless pulses response) filter.FIR fractional time delay filter can pass through the designs such as sinc (Singh) window function, Lagrangian interpolation, maximally-flat degree FIR filter, WLS (Weighted Least Squares, weighted least-squares) method, Oetken method.IIR fractional time delay filter can pass through the methods such as LS (least square) phase estimation, LS phase delay are estimated, group delay estimations of maximally-flat, the design of iteration WLS phase error, iteration WLS phase delay tolerance design and design.
Phase and magnitude passage time postpone a meeting or conference with changes in environmental conditions.The bandwidth of power supply modulator 23 can change with load current; When the power output of power amplifier 51 changes, the time delay of power supply modulator 23 also can change; Power supply modulator 23 time postpone a meeting or conference and vary with temperature.But the change procedure of two passages is slowly, after setting-up time section, polar coordinate transmitter re-starts the time delay of amplitude channels and phase path and estimates, to realize self adaptation, or, whether polar coordinate transmitter, after setting-up time arrives, is met the demands and is determined whether revising the parameter of variable time delay filter by test macro index, simplified self-adaptive process.
With reference to embodiment, show particularly and described the present invention above, for one of ordinary skill in the art, the thought according to the embodiment of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.
Claims (4)
1. polar coordinate transmitter, comprise polar coordinates generation unit, amplitude modulation unit, phase modulation unit, switch power amplifying unit, it is characterized in that, also comprise time delay estimation unit, variable fractional time delay filter, an output of described polar coordinates generation unit connects the input of amplitude modulation unit, another output of polar coordinates generation unit connects the input of phase modulation unit through variable fractional time delay filter, the control end of the output connecting valve power amplification unit of amplitude modulation unit, the input of the output connecting valve power amplification unit of phase modulation unit, amplitude modulation unit, phase modulation unit connect respectively the input of time delay estimation unit, and the output of time delay estimation unit is connected with the control end of variable fractional time delay filter,
Described time delay estimation unit, for estimate respectively the integer time delay of phase path and amplitude channels in time domain, carries out, after integer delay compensation, estimating respectively the fractional delay of phase path and amplitude channels on frequency domain to phase path and amplitude channels; Finally the integer time delay error between phase path and amplitude channels and the addition of fractional delay error are obtained to time delay error, and according to the time delay error obtaining, variable fractional time delay filter is set;
Described variable fractional time delay filter, for the signal of input phase passage is carried out to time delay, carries out the time delay error compensation between phase path and amplitude channels.
2. polar coordinate transmitter as claimed in claim 1, it is characterized in that, described phase modulation unit comprises digital to analog converter, reconfigurable filter, phase-modulator, the output of the digital to analog converter in phase modulation unit is connected with the input of reconfigurable filter, and the output of reconfigurable filter is connected with the input of phase-modulator; Described amplitude modulation unit comprises digital to analog converter, reconfigurable filter, power supply modulator, and the output of the digital to analog converter in amplitude modulation unit is connected with the input of reconfigurable filter, and the output of reconfigurable filter is connected with the input of power supply modulator;
Described time delay estimation unit, for by integer time delay and fractional delay that the integer time delay producing through reconfigurable filter and power supply modulator in amplitude channels and fractional delay are estimated to obtain amplitude channels, integer time delay and the fractional delay of to passing through integer time delay that reconfigurable filter and phase-modulator produce and fractional delay in phase path, estimating to obtain phase path.
3. polar coordinate transmitter as claimed in claim 1, it is characterized in that, described phase modulation unit comprises digital to analog converter, reconfigurable filter, phase-modulator, the output of the digital to analog converter in phase modulation unit is connected with the input of reconfigurable filter, and the output of reconfigurable filter is connected with the input of phase-modulator; Described amplitude modulation unit comprises digital to analog converter, reconfigurable filter, power supply modulator, and the output of the digital to analog converter in amplitude modulation unit is connected with the input of reconfigurable filter, and the output of reconfigurable filter is connected with the input of power supply modulator;
Described time delay estimation unit, for by integer time delay and fractional delay that the integer time delay producing through power supply modulator in amplitude channels and fractional delay are estimated to obtain amplitude channels, integer time delay and the fractional delay of to passing through integer time delay that phase-modulator produces and fractional delay in phase path, estimating to obtain phase path.
4. polar coordinate transmitter as described in claim 2 or 3, is characterized in that, described time delay estimation unit, for estimating the integer time delay of amplitude channels in time domain: order by related operation
corresponding d when related operation maximum
aMfor the integer time delay of amplitude channels, wherein, the number that N is sampled point, n is temporary variable, * is for asking conjugation, x
aM(n) be time domain input signal corresponding to amplitude channels up-sampling point n, y
aM(n-d
aM) be time domain output signal corresponding to amplitude channels up-sampling point n;
By related operation, estimate the integer time delay of phase path in time domain: order
corresponding d
pMfor the integer time delay of phase path, wherein, the number that N is sampled point, n is temporary variable, * is for asking conjugation, x
pM(n) be time domain input signal corresponding to phase path up-sampling point n, y
pM(n-d
pM) be time domain output signal corresponding to phase path up-sampling point n;
By related operation, estimate the fractional delay of amplitude channels on frequency domain: order
corresponding d '
aMfor the fractional delay of amplitude channels, wherein, X
aM(e
j ω) be frequency domain input signal corresponding to amplitude channels upper frequency ω after integer delay compensation,
for frequency domain output signal corresponding to amplitude channels upper frequency ω after integer delay compensation;
By related operation, estimate the fractional delay of phase path on frequency domain: order
the fractional delay that corresponding d ' PM is phase path, wherein, X
pM(e
j ω) be frequency domain input signal corresponding to phase path upper frequency ω after integer delay compensation,
for frequency domain output signal corresponding to phase path upper frequency ω after integer delay compensation.
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Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103516644B (en) * | 2012-06-21 | 2018-07-24 | 南京中兴新软件有限责任公司 | Transmitting terminal inphase quadrature calibrates the output method and device of distortion parameter |
| CN103457602B (en) * | 2013-09-12 | 2016-08-31 | 电子科技大学 | A kind of broadband signal phase modulator and modulator approach thereof |
| CN103455069B (en) * | 2013-09-12 | 2015-04-29 | 电子科技大学 | Broadband amplitude signal power supply modulator and modulation method thereof |
| CN103560758B (en) * | 2013-11-15 | 2016-09-07 | 上海无线电设备研究所 | A kind of power amplifier for polar coordinate transmitter |
| CN103969626A (en) * | 2014-05-20 | 2014-08-06 | 西安电子科技大学 | Wideband digital wave beam forming method based on all-pass type variable fractional delay filter |
| CN104808738B (en) * | 2015-04-24 | 2017-03-22 | 昆腾微电子股份有限公司 | Amplitude modulation circuit, signal emission circuit and card reader |
| CN107171644B (en) * | 2016-03-08 | 2020-08-28 | 南方科技大学 | Modulation signal generating circuit based on phase adjuster |
| CN106849880A (en) * | 2016-12-29 | 2017-06-13 | 中国电子科技集团公司第五十研究所 | Efficient linear digital radio frequency power signal generating method based on polar coordinates treatment |
| CN107332539B (en) * | 2017-06-30 | 2020-09-15 | 电子科技大学 | High-speed parallel multi-path fractional delay filter implementation method |
| CN108777569A (en) * | 2018-05-23 | 2018-11-09 | 成都玖锦科技有限公司 | Arbitrary time-delay method based on multiphase filter |
| CN109274631B (en) * | 2018-12-11 | 2021-04-23 | 北京无线电测量研究所 | Data symbol synchronization method based on all-pass fractional delay filter |
| CN111030611A (en) * | 2019-11-15 | 2020-04-17 | 安凯(广州)微电子技术有限公司 | Polar coordinate modulation circuit and modulation method thereof |
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| CN102143097A (en) * | 2010-11-04 | 2011-08-03 | 华为技术有限公司 | Method and device for correcting delay difference of polar coordinate transmitter, and communication system |
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| CN101416406A (en) * | 2003-09-26 | 2009-04-22 | 诺基亚公司 | Method and apparatus to compensate AM-PM delay mismatch in envelope restoration transmitter |
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| CN102143097A (en) * | 2010-11-04 | 2011-08-03 | 华为技术有限公司 | Method and device for correcting delay difference of polar coordinate transmitter, and communication system |
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