Summary of the invention
The present invention seeks to solve distorted signal extracting loops carrier wave in feed-forward technique and, on the impact of enjoying frequency parameter change, ensure the stable of the linear and work of amplifier under very wide bandwidth.
Technical scheme of the present invention is a kind of feed forward power amplifier for adaptive frequency compensation, comprise the first power splitter, first phase vector adjuster, the digital device detecting frequency, main amplifier, the first coupler, filtering wave by prolonging time device, the first mixer, the first amplitude vector adjuster, the second power splitter, the second coupler, delayer, the second mixer, the second amplitude vector adjuster, second phase vector adjuster, error amplifier, wave detector and control module
First power splitter connects first phase vector adjuster and delayer respectively, first phase vector adjuster, the digital device detecting frequency, main amplifier, the first coupler, filtering wave by prolonging time device connect successively, and the coupled signal of the first coupler exports and inputs the second power splitter through the first amplitude vector adjuster; The output of the second power splitter connects a road input of digital device and the second mixer detecting frequency respectively, and delayer connects another road input of the second mixer; The output of the second mixer connects the second coupler, the second amplitude vector adjuster, second phase vector adjuster, error amplifier successively, and the coupled signal of the second coupler exports access wave detector; Filtering wave by prolonging time device is connected the first mixer with error amplifier; Control module with detect the digital device of frequency, first phase vector adjuster, second phase vector adjuster, the first amplitude vector adjuster, the second amplitude vector adjuster and wave detector and be connected respectively.
And, the first amplitude vector adjuster and the first amplitude vector adjuster is adopted to regulate the first order to offset loop, the second amplitude vector adjuster and the second amplitude vector adjuster is adopted to regulate the second level to offset loop, the described first order is offset loop and is comprised the first power splitter, main amplifier, the first coupler, the second power splitter, delayer and the second mixer, and the described second level is offset loop and comprised the second coupler, error amplifier and the first mixer formation second level counteracting loop;
After mobile communication signal enters, first by the first power splitter, the mobile communication signal of input is divided into two parts by the first power splitter, wherein a part of signal is designated as A1, signal A1 is through first phase vector adjuster, and input to the digital device detecting frequency and process, after process, signal is input to main amplifier, by the first coupler after main amplifier amplifies, the through connect signal of the first coupler enters the first mixer through filtering wave by prolonging time device; The coupled signal that first coupler produces is after the first amplitude vector adjuster, be divided into two parts through the second power splitter, a part of signal is designated as B1, and signal B1 feeds back to the digital device detecting frequency, another part signal is designated as B2, and signal B2 enters the second mixer;
Another road signal that first power splitter exports is designated as A2, and signal A2 enters the second mixer after delayer time delay, and two paths of signals A2 and B2 cancels each other at the second mixer place; Second mixer output signal enters the second coupler, the coupled signal input wave detector that the second coupler produces; Control module, according to wave detector gained detected value size adjustment first amplitude vector adjuster and first phase vector adjuster, makes the second mixer output signal gross power minimum, extracts distorted signal; The through connect signal that distorted signal exports through the second coupler adjusts through the second amplitude vector adjuster, second phase vector adjuster, is then amplified into the first mixer through error amplifier; The two paths of signals entering the first mixer completes counteracting at the first mixer place, and after obtaining closing road, signal is the very high radio frequency amplifying signal of the linearity.
And, in control module, preset second phase vector adjuster and the second amplitude vector adjuster respective frequencies arranges table, control module, according to the signal B1 feeding back to the digital device detecting frequency, regulates second phase vector adjuster and the second amplitude vector adjuster.
Compared to the prior art, tool of the present invention has the following advantages: first, and instant invention overcomes the shortcoming of traditional pilot input method circuit complexity, circuit simply, easily realizes, and cost is low.Secondly, solve minimum power and detect the drawback that self adaptation cannot be applied in the second ring.Again, can not introduce new distortion frequency, it is stronger that ability is offset in linearisation.Finally, the mapping relations of signal amplitude, phase place and incoming frequency are extracted according to distortion built-in in advance, after input signal being detected, amplitude and the error of distortion being extracted signal are set to optimum state, thus solve the error amplifier problem that the linearity of different frequency is inconsistent in device bandwidth, increase the bandwidth of Feed Forward Power Amplifier, and achieve the consistency in linear compensation full bandwidth.
Embodiment
The feed forward power amplifier that the present invention proposes can realize adaptive frequency compensation, the change that the frequency of input carrier signal followed by the error vector adjuster of feed forward power amplifier regulates distortion to extract amplitude and the phase place of signal automatically, thus make distortion extraction signal offset the counteracting state being in the best in loop all the time at distorted signal, thus the linearity of Feed Forward Power Amplifier is made to reach optimum.
Technical solution of the present invention is described in detail below in conjunction with drawings and Examples.
Refer to Fig. 2, the present invention specifically comprises: digital device, main amplifier, the first coupler, filtering wave by prolonging time device, the first mixer, the first amplitude vector adjuster, the second power splitter, the second coupler, delayer, the second mixer, the second amplitude vector adjuster, second phase vector adjuster, error amplifier, wave detector, the control module of the first power splitter, first phase vector adjuster, detection frequency.
First power splitter connects first phase vector adjuster and delayer respectively, first phase vector adjuster, the digital device detecting frequency, main amplifier, the first coupler, filtering wave by prolonging time device connect successively, and the coupled signal of the first coupler exports and inputs the second power splitter through the first amplitude vector adjuster; The output of the second power splitter connects a road input of digital device and the second mixer detecting frequency respectively, and delayer connects another road input of the second mixer; The output of the second mixer connects the second coupler, the second amplitude vector adjuster, second phase vector adjuster, error amplifier successively, and the coupled signal of the second coupler exports access wave detector; Filtering wave by prolonging time device is connected the first mixer with error amplifier.Control module with detect the digital device of frequency, first phase vector adjuster, second phase vector adjuster, the first amplitude vector adjuster, the second amplitude vector adjuster and wave detector and be connected respectively.Wherein, form the first order primarily of the first power splitter, main amplifier, the first coupler, the second power splitter, delayer and the second mixer and offset loop, form the second level primarily of filtering wave by prolonging time device, the second coupler, error amplifier and the first mixer and offset loop.
Operation principle: mobile communication signal (RFin) enters after embodiment provides power amplifier, first by the first power splitter, input signal is divided into two parts by the first power splitter, wherein a part of signal is designated as A1, and signal A1, through first phase vector adjuster, inputs to the digital device detecting frequency and processes, after process, signal is input to main amplifier, after main amplifier amplifies, by the first coupler, the through connect signal of the first coupler enters the first mixer through filtering wave by prolonging time device.The coupled signal that first coupler produces is through the first amplitude vector adjuster, be divided into two parts through the second power splitter after adjusting range, a part of signal is designated as B1, and signal B1 feeds back to the digital device detecting frequency, another part signal is designated as B2, and signal B2 enters the second mixer.Another road signal that first power splitter exports is designated as A2, and signal A2 enters the second mixer after delayer time delay, and two paths of signals A2 and B2 cancels each other at the second mixer place.Second mixer output signal enters the second coupler, and the coupled signal input wave detector that the second coupler produces is used for power detection.Control module, according to wave detector detected value size, regulates the first amplitude vector adjuster and first phase vector adjuster automatically, and make the second mixer output signal gross power minimum, namely keynote signal is cancelled, and extracts distorted signal.Through connect signal that signal exports through the second coupler carries out amplitude and phase place adjustment through the second amplitude vector adjuster, second phase vector adjuster is extracted in this distortion, then after error amplifier amplification, enter the first mixer.The two paths of signals entering the first mixer completes counteracting at the first mixer place, and after obtaining closing road, signal is the very high radio frequency amplifying signal (RFout) of the linearity.
For the sake of ease of implementation, the amplifier specific implementation of embodiment is provided to be described as follows:
Detect the digital device of frequency, this functions of modules to detect frequency and the watt level of input signal in real time, and these data are transferred to control module, and the phase and magnitude modulation of signal is extracted in the distortion that can be used for the second loop;
Main amplifier, comprises at least three grades of power tubes of cascade, amplifies the signal of input, and the power output of power amplifier is exactly amplified by main amplifier to export, and can produce nonlinear distortion component;
Error amplifier, comprises at least level Four power tube of cascade, amplifies the distorted signal extracted;
First coupler, exports radiofrequency signal from main amplifier the road radiofrequency signal that is coupled;
Second coupler, exports radiofrequency signal the road radiofrequency signal that is coupled after the second mixer;
First mixer, from error amplifier output signal, a coupling part and the synthesis of filtering wave by prolonging time device output signal power, balance out the distorted signal contained in main amplifier output signal;
Second mixer, the coupled signal that the coupled signal that the first coupler produces produces with the second coupler after delay circuit, at mixer place power combing, balances out carrier signal, extracts distorted signal;
First power splitter, is divided into two paths of signals by input signal, and a road is used for amplifying, and another road is used for carrier wave and offsets;
Second power splitter, is divided into two paths of signals by the coupled signal of the first coupler, and frequency detecting and power detection process are done for feeding back to the digital device detecting frequency in a road;
Delayer, the road signal produced for the first power splitter provides certain time delay;
Filtering wave by prolonging time device, the output for main amplifier provides certain time delay;
First phase vector adjuster, regulates the first order to offset the phase place exporting amplifying signal in loop; First amplitude vector adjuster, regulates the first order to offset the amplitude of coupled signal in loop;
Second phase vector adjuster, regulates the second level to offset the phase place exporting amplifying signal in loop;
Second amplitude vector adjuster, regulates the second level to offset the amplitude of coupled signal in loop;
Wave detector, the watt level after function signal pre-amplification;
Control module, the performance number of monitoring detecting circuit, and according to the frequency that the digital device detecting frequency reports, automatic control phase vector adjuster and amplitude vector adjuster.
Each parts can adopt prior art to have circuit devcie realization above, and the digital device and the control module that detect frequency can adopt software mode to pre-set working method by those skilled in the art voluntarily as required.
When specifically carrying out frequency compensation self adaptation, the adjustment of first order counteracting loop can according to existing techniques in realizing, the adjustment of second level counteracting loop can extract the mapping relations of signal amplitude, phase place and incoming frequency according to distortion, at control module internal initialization preset table, under this preset form is used for corresponding varying input signal frequency, the phase and magnitude that signal is extracted in distortion is set.This table is by advance through go-and-return test, under the input signal of different frequency, debugging second phase vector adjuster and the second amplitude vector adjuster, the linearity of statistics output signal, the record linearity preferably time second phase vector adjuster and the settings of the second amplitude vector adjuster, then to make form in the control module preset for corresponding signal frequency now.During normal work, the digital device detecting frequency reports frequency input signal data, can arrange second phase vector adjuster and the second amplitude vector adjuster by table look-at, the phase and magnitude of signal is extracted in initialization distortion, and the self adaptation completing the second loop is fast arranged.
For the sake of ease of implementation, below introduce the embodiment of the present invention detailed process steps when amplifier operation is provided, perform one time according to following steps order during power-up initializing, then enter the self adaptation circulation adjustment stage:
Step 1: radiofrequency signal enters after embodiment provides power amplifier, is introduced into the first power splitter.These signals can be the signals of the existing standard different frequency range of GSM, CDMA, WCDMA etc.;
Step 2: radiofrequency signal is after step 1 processes, and be divided into two paths of signals, a road is (signal A1) signal to be amplified, a road is for extracting signal (signal A2).Power splitter power division is determined on a case-by-case basis, and usually can be considered that constant power distributes.Now power is very little to extract signal, only containing input carrier signal, not containing nonlinear distortion signal.
Step 3: the A1 signal to be amplified in step 2, after first phase vector adjuster, the phase place of this signal adjustable., the initial value of first phase vector adjuster is in the control module preset, regulates during power-up initializing by initial value, follow-uply can automatically regulate.
Step 4: the extraction signal A2 in step 2, enter delayer, the time delay that delayer produces, should equal A1 signal to be amplified in theory after detecting the digital device of frequency, main amplifier, the first coupler, the first amplitude vector adjuster, the second amplifirer, enter the time delay that the second mixer produces.
Step 5: the signal of adjustable phase place in step 3, enter the digital device detecting frequency, carry out size and frequency information that input signal is extracted in digital processing, extract the data obtained and be transferred to control module for adapting data processing, concrete extracting mode is prior art, and it will not go into details in the present invention.
Step 6: the signal of process in step 5, exports after main amplifier amplifies, and creates distorted signal in its output signal.
Step 7: the output signal in step 6, by the first coupler coupling, produces two paths of signals, is respectively through connect signal and coupled signal.Through connect signal decay is very little, and the degree of coupling is greater than 30dB usually.
Step 8: the through connect signal in step 7, after the time delay of filtering wave by prolonging time device, gained time delayed signal enters the first mixer, the time delay of filtering wave by prolonging time device generation herein, equals the time delay that the coupled signal in step 7 produces after the first amplitude vector adjuster, the second power splitter, the second mixer, the second coupler, the second amplitude vector adjuster, second phase vector adjuster, error amplifier in theory.
Step 9: the coupled signal produced in step 7, through the first amplitude vector adjuster, carry out amplitude modulation process, the first amplitude vector adjuster is directly controlled by control module, regulates during power-up initializing by initial value, follow-uply can automatically regulate.
Step 10: through the signal of the first amplitude vector adjuster process in step 9, through the second power splitter, be divided into two paths of signals, a road signal (signal B1) is for feedback, and a road signal (signal B2) is for closing road.Be generally constant power herein to distribute.
Step 11: the signal B1 for feeding back in step 10, input detects the digital device of frequency, the digital device detecting frequency uses this signal B1 to compare with the input signal A1 in step 3, produces size and the frequency data of input signal A1, is transferred to control module.Specific implementation can adopt prior art, and the digital device such as detecting frequency adopts the SC1887 chip of Scintera company.Wherein, the transmission intercal of the digital device of predeterminable detection frequency, such as, complains to size and the frequency information of control module output signal when arranging the digital device interval 20MS detecting frequency.
Step 12: the signal B2 for closing road in step 10, enter the second mixer, the delay time signal produced with delayer in step 4 closes road, and two paths of signals cancels each other, and extracts distorted signal.
Step 13, the distorted signal exported after offsetting in step 12, by the second coupler, produces two paths of signals and is respectively through connect signal and coupled signal.The degree of coupling is designed to 10dB herein.
Step 14: the through connect signal in step 13, through the second amplitude vector adjuster, carries out amplitude modulation process, obtains the second amplitude vector adjuster and is directly controlled by control module, can automatically regulate.
Step 15: the amplitude-modulated signal in step 14, through second phase vector adjuster, carries out phase modulation process, and second phase vector adjuster is directly controlled by control module, can automatically regulate.During concrete enforcement, the signal magnitude that control module is complained to according to the digital device detecting frequency in step 11 and frequency data, look into the second built-in amplitude vector adjuster and the preset table of second phase vector adjuster, second amplitude vector adjuster and second phase vector adjuster are set to corresponding state
Step 16: the signal through amplitude modulation and phase modulation in step 15, amplify through error amplifier, signal power is less herein, error amplifier be linearly much better than main amplifier, the distorted signal of generation can be ignored and not remember.
Step 17: in step 16 through amplifying signal, enter the first mixer, close road with the time delayed signal produced in step 8, balance out the distortion component in time delayed signal, improve its linearity.After closing road, signal is the very high radio frequency amplifying signal of the linearity.
Self adaptation circulation regulates phase lasts to carry out, and concrete adjustment realizes as follows:
(1) coupled signal of the second coupler (see step 13), is detected to its size by wave detector, exports the magnitude of voltage corresponding with watt level to control module process.
(2) control module is according to detecting the current signal magnitude of complaining to of the digital device of frequency and frequency data (see detecting step 11), look into the second built-in amplitude vector adjuster and the preset table of second phase vector adjuster, the second amplitude vector adjuster and second phase vector adjuster are set to corresponding state.
(3) control module is for the purpose of wave detector detection voltage is minimum, and Lookup protocol first amplitude vector adjuster and first phase vector adjuster, with the counteracting situation that correspondence is different, specific implementation is prior art.Control module regulates the first amplitude vector adjuster and first phase vector adjuster can change the counteracting situation of the second mixer (see step 12), the changed power that Shi He road exports, thus cause Coupled Signal Power (see step 13) change, thus to cause wave detector to detect change in voltage.
(4) when frequency input signal changes, the digital device detecting frequency can detect and changes and pass to control module, and now control module returns (1), keeps wave detector to detect voltage be adjusted to minimum through circulation Automatic adjusument.
When wave detector power detection is adjusted to minimum, carrier signal can be cancelled minimum, and distorted signal extracts purer, and the neutralization effect of last first mixer is better.
Above-mentioned adaptive adjustment, is arranged for the purpose of power detection is minimum automatically, in real time, ensure that carrier wave offsets and remains and offset best, eliminate the impact of environment and temperature parameter change.And when frequency input signal changes, by the second preset amplitude vector adjuster and second phase vector adjuster, table is set, the distorted signal at the first mixer place is offseted and is adjusted to optimum state, and then automatically, in real time arrange to ensure that the second mixer place carrier signal offsets to optimum state.Therefore achieve the adaptive control that Liang Chuhe road is offseted, improve and offset precision, and increase and offset frequency bandwidth, ensure that the consistency of equipment full bandwidth linear compensation.
Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendment or supplement or adopt similar mode to substitute to described specific embodiment, but can't depart from spirit of the present invention or surmount the scope that appended claims defines.