CN101115037B - Digital receiver and local oscillating frequency inceptive error calibrating method - Google Patents

Abstract

The invention discloses a calibration method for a digital receiver and the initial error of the vibration frequency of the digital receiver. The invention comprises the following steps that : A. a signal generator is used for generating a reference monosyllabic signal and the signal is sent to the digital receiver; B. the digital receiver mixes a vibration signal and the reference syllabic signal, after a lo-pass filter sampling of the mixed signals, performs Fourier transformation on a sampling signal to get a digital baseband signal frequency; C. the vibration signal frequency is calculated and obtained according to the digital baseband signal frequency and the reference monosyllabic frequency; D. the initial error calibration of the vibration frequency is performed according to the vibration signal frequency and a nominal vibration signal frequency. The calibration method for the digital receiver and the initial error of the vibration frequency of the digital receiver can effectively increase the calibration speed and lower the calibration cost.

Description

The method of a kind of digital receiver and local oscillating frequency inceptive error calibrating thereof

Technical field

The invention belongs to wireless communication field, particularly relate to the method for a kind of digital receiver and local oscillating frequency inceptive error calibrating thereof.

Background technology

In wireless communication system, digital receiver is in order to guarantee the demodulation quality of received signal, and the frequency error that needs to guarantee receiver local frequency and signal carrier is less than certain limit, and this scope has different requirements in different systems.When being in correct accepting state, receiver can calculate the frequency departure of local oscillation signal and received signal by the method for channel estimating and in time adjust, and makes the deviation of local frequency and received signal carrier frequency satisfy requirement of system design.

For the receiver that just begins to set up accepting state, the frequency departure of local frequency and received signal carrier frequency also must just can make the correct estimating received signal frequency deviation of receiver and enter correct accepting state less than certain designing requirement.Because the influence of device technology water product and device inconsistency, the original frequency of receiver oscillator output signal and its nominal value have certain deviation.For the initial frequency deviation that makes local oscillation signal frequency and its nominal frequency satisfies requirement of system design, receiver need be calibrated before dispatching from the factory usually, makes its error range compliance with system designing requirement.

The method of existing receiver local oscillating frequency inceptive error calibrating, typically use spectrum analyzer and directly or indirectly measure the frequency of local oscillation signal, calibrate according to measuring frequency and its nominal frequency then, calculate the frequency control word of nominal frequency correspondence, and the frequency control word that obtains is written in the receiver.Like this, when receiver starts, frequency control word is carried out producing after the digital-to-analogue conversion control voltage of oscillator, the control generator output signal frequency is its nominal frequency, thereby makes adjusted local frequency satisfy requirement of system design.The shortcoming of this method is to use the frequency spectrograph of price comparison costliness, and calibration speed is slower, and calibration data also needs to be written in the receiver by additive method, the system construction more complicated.

Summary of the invention

Technical problem to be solved by this invention provides the method for a kind of digital receiver and local oscillating frequency inceptive error calibrating thereof, to improve calibration speed, reduces the calibration cost.

For solving the problems of the technologies described above, it is as follows to the invention provides technical scheme:

A kind of method of digital receiver local oscillating frequency inceptive error calibrating comprises the steps:

A, utilize signal generator to produce, and output to described digital receiver with reference to tone signal;

B, described digital receiver are with local oscillation signal and describedly carry out mixing with reference to tone signal, mixed frequency signal is carried out the low-pass filtering post-sampling, and sampled signal is carried out Fourier transform, obtain the digital baseband signal frequency;

C, according to described digital baseband signal frequency with reference to the tone signal frequency, calculate the local oscillation signal frequency;

D, carry out local oscillating frequency inceptive error calibrating according to described local oscillation signal frequency and local oscillation signal nominal frequency.

Preferably, among the described step C, in reference tone signal frequency during greater than the local oscillation signal frequency, according to $f_o=\frac{f_{\mathrm{ref}}\·\stackrel{\‾}{f_o}}{\stackrel{\‾}{f_o}+\hat{f}}$ Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to $f_o=\frac{f_{\mathrm{ref}}\·\stackrel{\‾}{f_o}}{\stackrel{\‾}{f_o}-\hat{f}}$ Calculate the local oscillation signal frequency, wherein, f _oBe local oscillation signal frequency, f _RefBe reference tone signal frequency, f _oBe the local oscillation signal nominal frequency, Be the digital baseband signal frequency.

Preferably, among the described step C, in reference tone signal frequency during greater than the local oscillation signal frequency, according to $f_o=f_{\mathrm{ref}}-\hat{f}$ Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to $f_o=f_{\mathrm{ref}}+\hat{f}$ Calculate the local oscillation signal frequency, wherein, f _oBe local oscillation signal frequency, f _RefBe reference tone signal frequency,

Be the digital baseband signal frequency.

Preferably, described step D specifically comprises:

According to $k=\frac{f_{o,c_2}-f_{o,c_1}}{c_2-c_1}$ Calculate the FREQUENCY CONTROL coefficient, wherein, k is the FREQUENCY CONTROL coefficient, f _{O, c1}Be frequency control word c ₁Corresponding local oscillation signal frequency, f _{O, c2}Be frequency control word c ₂Corresponding local oscillation signal frequency;

According to $\stackrel{\‾}{c}=\left[\frac{{\stackrel{\‾}{f}}_o-f_{o,c_1}}{k}\right]+c_1$ Calculate the frequency control word of local oscillation signal nominal frequency correspondence, wherein, c is the frequency control word of local oscillation signal nominal frequency correspondence, f _oBe the local oscillation signal nominal frequency, [] is rounding operation.

Preferably, in the described steps A, describedly further output to a plurality of digital receivers by power divider with reference to tone signal.

A kind of digital receiver comprises voltage controlled oscillator, frequency mixer, low pass filter, analog to digital converter, Fourier transformer, local oscillation signal frequency calculator, error corrector device, digital to analog converter, wherein:

Voltage controlled oscillator is used to produce local oscillation signal;

Frequency mixer is used to receive the reference tone signal of local oscillation signal and signal generator output, and carries out mixing with local oscillation signal with reference to tone signal;

Low pass filter is used for mixed frequency signal is carried out low-pass filtering;

Analog to digital converter is used for filtered signal is sampled;

Fourier transformer is used for sampled signal is carried out Fourier transform, obtains the digital baseband signal frequency;

The local oscillation signal frequency calculator is used for calculating the local oscillation signal frequency according to the digital baseband signal frequency with reference to the tone signal frequency;

Error corrector device is used for carrying out local oscillating frequency inceptive error calibrating according to local oscillation signal frequency and local oscillation signal nominal frequency;

Digital to analog converter, the frequency control word that is used for that calibration is obtained carries out producing control voltage of voltage-controlled oscillator after the digital-to-analogue conversion.

Compared with prior art, the invention has the beneficial effects as follows:

Equipment investment is few: compare with existing method, the present invention has saved expensive spectrum analyzer, only just can realize the local oscillating frequency inceptive error calibrating of multi-receiver with the tone signal generator of a relative low price;

Calibration speed is fast: in the present invention, receiver utilizes simple formula just can calculate the actual frequency of local oscillation signal after baseband signal is done the FFT conversion, for most digital receivers, this process can be finished in several milliseconds, and existing calibration system is when utilizing frequency spectrograph to do calibration, usually need the several seconds just can finish the calibration of a receiver, the present invention can significantly improve the speed of calibration by contrast;

The calibration of support multiple terminals: the present invention can support the multi-section receiver to calibrate simultaneously, and theoretically, the receiver quantity that the present invention supported only is subjected to the restriction of signal generator power output;

The calibration cost is low: because equipment investment minimizing and calibration efficiency improve, the time and the instrument and equipment cost of the calibration of receiver are significantly reduced.

Description of drawings

Fig. 1 is the method flow diagram of the digital receiver local oscillating frequency inceptive error calibrating of preferred embodiment of the present invention;

Fig. 2 is a digital receiver prevention at radio-frequency port input signal schematic diagram;

Fig. 3 is the analog baseband signal schematic diagram after the frequency conversion;

Fig. 4 is the digital receiver structural representation of preferred embodiment of the present invention;

Fig. 5 is an application example that utilizes method of the present invention that a plurality of digital receivers are calibrated simultaneously.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, describe the present invention below in conjunction with the accompanying drawings and the specific embodiments.

The present invention utilizes signal generator to produce with reference to tone signal, digital receiver receive this with reference to tone signal after after digital baseband is measured frequency conversion the frequency of signal, according to the digital baseband signal frequency that measures with reference to tone signal frequency computation part receiver local oscillation signal frequency, calibrate according to described local oscillation signal frequency and local oscillation signal nominal frequency, make the initial error of local frequency reach the requirement of system design.

Please refer to Fig. 1, the method for the digital receiver local oscillating frequency inceptive error calibrating of preferred embodiment of the present invention comprises the steps:

Step 101, utilize signal generator to produce, and output to digital receiver with reference to tone signal;

If S _RefBe the sine wave signal that is produced by signal generator, its frequency is f _RefThe local oscillation signal of receiver is S _o, its frequency is f _o, and the satisfied f that concerns _o＜f _RefThe channel width of receiver is BW, and satisfies relation:

$f_{\mathrm{ref}}-f_o<\frac{1}{2}\mathrm{BW}---\left(1\right)$

Step 102, digital receiver carry out mixing with local oscillation signal with reference to tone signal, mixed frequency signal is carried out the low-pass filtering post-sampling, and sampled signal is carried out Fourier transform, obtain the digital baseband signal frequency;

At digital receiver frequency mixer input, as shown in Figure 2 with reference to the relation of tone signal and local oscillation signal.In frequency mixer inside, the two-way input signal is done multiply operation, realizes frequency spectrum shift.In the receiver Analog Baseband, the frequency spectrum of signal as shown in Figure 3.At digital baseband, do Fourier transform to received signal, can obtain the digital baseband signal frequency

Here need to prove f _o＜f _RefThe hypothesis just done of qualification for the convenience of subsequent formulae derivation, in fact this method also is applicable to f fully _o＞f _RefSituation, just derivation of equation process and result understand slightly different.

Step 103, according to the digital baseband signal frequency with reference to the tone signal frequency, calculate the local oscillation signal frequency;

Be input to the reference tone signal S of digital receiver _RefCan be expressed as:

The receiver local oscillation signal can be expressed as:

S _o＝Bcos(2πf _ot+θ) (3)

In frequency mixer, multiply each other with reference to tone signal and local oscillation signal, produce new spectrum component S _Abb:

$S_{\mathrm{abb}}=S_{\mathrm{ref}}\&CenterDot;S_o$

For analog baseband signal, because the effect of low pass filter, the high frequency item is by filtering, so following formula can further be simplified shown as:

(5)

$=\frac{1}{2}\mathrm{AB}\cos [2\mathrm{\&pi;f}\&CenterDot;t+\mathrm{\&phi;}]$

Wherein, f=f _Ref-f _o F is the analog baseband signal frequency.

So far, the frequency of receiver local oscillation signal can be expressed as:

f _o＝f _ref-f (6)

If local oscillator output signal nominal frequency is f _o, local oscillator output signal frequency error coefficient k then _ErrCan be expressed as:

$k_{\mathrm{err}}=\frac{f_o-{\stackrel{\&OverBar;}{f}}_o}{{\stackrel{\&OverBar;}{f}}_o}---\left(7\right)$

That is f, _o=(1+k _Err) f _o

For analog baseband signal, its actual frequency is f, has according to formula (6):

f＝f _ref-f _o (8)

In digital receiver system, the work clock of radio frequency and baseband circuit is all produced by phase-locked loop circuit by same oscillator output signal usually, therefore before the accurate calibration of system clock quilt, the sampling clock frequency in the system has the error coefficient identical with the voltage controlled oscillator output signal frequency.Because there is error in sampling clock, the therefore digital baseband signal frequency that obtains by Fourier transform

Also exist the error coefficient identical with the sampling clock frequency, but opposite in sign.If be sample frequency because error rising α doubly, then the digital baseband signal frequency that obtains through Fourier transform can reduce α doubly.

Thus, the frequency values of digital baseband signal can be expressed as (ignoring the frequency computation part error that the limited sampling point brings herein):

$\hat{f}=\frac{f}{1+k_{\mathrm{err}}}---\left(9\right)$

That is:

$f=(1+k_{\mathrm{err}})\hat{f}---\left(10\right)$

Have according to formula (8) and formula (10):

$(1+k_{\mathrm{err}})\hat{f}=f_{\mathrm{ref}}-f_o---\left(11\right)$

Can get the following formula conversion:

$k_{\mathrm{err}}=\frac{f_{\mathrm{ref}}-{\stackrel{\&OverBar;}{f}}_o-\hat{f}}{{\stackrel{\&OverBar;}{f}}_o+\hat{f}}---\left(12\right)$

So far, local oscillation signal frequency f _oCan be expressed as:

$f_o=\frac{f_{\mathrm{ref}}\&CenterDot;\stackrel{\&OverBar;}{f_o}}{\stackrel{\&OverBar;}{f_o}+\hat{f}}---\left(13\right)$

According to formula (11), the local oscillation signal frequency can be expressed as again:

$f_o=f_{\mathrm{ref}}-(1+k_{\mathrm{err}})\hat{f}---\left(14\right)$

Work as k _Err＜＜1 o'clock, digital receiver local oscillation signal frequency f _oBut approximate representation is:

$f_o=f_{\mathrm{ref}}-\hat{f}---\left(15\right)$

When the frequency error coefficient was far smaller than 1, its local frequency error can be expressed as formula (15) approx.Compare with formula (13), the computational methods of formula (15) are because no division arithmetic can effectively reduce operand, and the approximate error that it brings can be ignored.For instance, if f _o=900.000000MHz, f _Ref=900.050000MHz, $\hat{f}=0.040000\mathrm{MHz},$ Calculate f according to formula (13) _o=900.0099996MHz, and calculate f according to formula (15) _o=900.010000MHz, both compare as can be seen, and the error of calculation of two formulas is less than 0.5Hz.

Similarly, for f _o＞f _RefSituation, formula (13) and (15) are changed to respectively:

$f_o=\frac{f_{\mathrm{ref}}\&CenterDot;\stackrel{\&OverBar;}{f_o}}{\stackrel{\&OverBar;}{f_o}-\hat{f}}---\left(13^{,}\right)$

$f_o=f_{\mathrm{ref}}+\hat{f}---\left({15}^{,}\right)$

Step 104, carry out local oscillating frequency inceptive error calibrating according to local oscillation signal frequency and local oscillation signal nominal frequency.

After calculating the local oscillation signal frequency, just can calibrate according to local oscillation signal frequency and its nominal frequency, calculate the frequency control word of nominal frequency correspondence, and the frequency control word that obtains is preserved.Like this, when receiver starts, frequency control word is carried out producing after the digital-to-analogue conversion control voltage of oscillator, the control generator output signal frequency is its nominal frequency, thereby makes adjusted local frequency satisfy requirement of system design.

In digital receiver, use voltage controlled oscillator to produce system's fundamental clock usually, use phase-locked loop circuit to produce the required clock signal of each subsystem work (local oscillation signal that comprises receiver) then.Because phase-locked loop circuit frequency of its output frequency of clock and input clock when lock-out state keeps constant proportionate relationship, so we can ignore the existence of phase-locked loop circuit, directly set up the relation between control signal and the local oscillation signal frequency.According to described local oscillation signal frequency and local oscillation signal nominal frequency, the control word of adjusting frequency c, frequency control word c produce the control voltage of oscillator, the output signal frequency of control generator after by digital-to-analogue conversion.

Concerning voltage controlled oscillator, there are relation one to one in its output signal frequency and input voltage, and this pass ties up in its control voltage allowed band and can use the first-order equation approximate representation usually, that is:

$f_{o,c}=k\&CenterDot;\left({c-c}_{\min }\right)+f_{o,c_{\min }}(c_{\min }\&le;c{\&le;c}_{\max })---\left(16\right)$

Wherein k represents FREQUENCY CONTROL coefficient, f _{O, c}The receiver local frequency of expression frequency control word c correspondence.c _MaxAnd c _MinBe the minimum and maximum value of frequency control word, its transformational relation by voltage controlled oscillator type and digital to analog converter is determined.

In the actual alignment process, can obtain the FREQUENCY CONTROL coefficient k by twice Calibration Method.It is c that frequency control word promptly is set earlier ₁, obtain its corresponding local oscillation signal frequency by above-mentioned steps 101～103

It is c that frequency control word is set then ₂, obtain its corresponding local oscillation signal frequency by above-mentioned steps 101～103 equally

Then the FREQUENCY CONTROL coefficient can be expressed as:

$k=\frac{f_{o,c_2}-f_{o,c_1}}{c_2-c_1}---\left(17\right)$

After calculating the FREQUENCY CONTROL coefficient, the pairing control word c of the nominal frequency of voltage controlled oscillator can be expressed as:

$\stackrel{\&OverBar;}{c}=\left[\frac{{\stackrel{\&OverBar;}{f}}_o-f_{o,c_1}}{k}\right]+c_1---\left(18\right)$

Wherein [] expression rounds.

Please refer to Fig. 4, be the structural representation of a kind of digital receiver of realizing said method.Described digital receiver comprises voltage controlled oscillator 10, frequency mixer 20, low pass filter 30, analog to digital converter 40, Fourier transformer 50, local oscillation signal frequency calculator 60, error corrector device 70 and digital to analog converter 80.Wherein:

Voltage controlled oscillator 10 is used to produce local oscillation signal.

Frequency mixer 20 is used to receive the reference tone signal of local oscillation signal and signal generator 90 outputs, and carries out mixing with local oscillation signal with reference to tone signal.

Low pass filter 30 is used for mixed frequency signal is carried out low-pass filtering, and for analog baseband signal, because the effect of low pass filter 30, the high frequency item is by filtering.

Analog to digital converter 40 is used for filtered signal is sampled.

Fourier transformer 50 is used for sampled signal is carried out Fourier transform, obtains the digital baseband signal frequency.

Local oscillation signal frequency calculator 60 is used for calculating the local oscillation signal frequency according to the digital baseband signal frequency with reference to the tone signal frequency.

During greater than the local oscillation signal frequency, calculate the local oscillation signal frequency in reference tone signal frequency, during less than the local oscillation signal frequency, calculate the local oscillation signal frequency according to formula (13 ') in reference tone signal frequency according to formula (13).

As previously mentioned, in order to reduce operand, when the frequency error coefficient is far smaller than 1, also can obtain the local oscillation signal frequency by approximate calculation.That is: during greater than the local oscillation signal frequency, calculate the local oscillation signal frequency in reference tone signal frequency, during less than the local oscillation signal frequency, calculate the local oscillation signal frequency according to formula (15 ') in reference tone signal frequency according to formula (15).

Error corrector device 70 is used for carrying out local oscillating frequency inceptive error calibrating according to local oscillation signal frequency and local oscillation signal nominal frequency.

After calculating the local oscillation signal frequency, just can calibrate according to local oscillation signal frequency and its nominal frequency, calculate the frequency control word of nominal frequency correspondence, and the frequency control word that obtains is preserved.Error corrector device 70 at first calculates the FREQUENCY CONTROL coefficient according to formula (17), calculates the pairing control word of nominal frequency of voltage controlled oscillator again according to formula (18).

Digital to analog converter 80 is used for frequency control word is carried out producing after the digital-to-analogue conversion control voltage of voltage controlled oscillator 10, and control generator 10 output signal frequency are its nominal frequency, thereby make adjusted local frequency satisfy requirement of system design.

From the process of above-mentioned digital receiver local oscillating frequency inceptive error calibrating as can be known, in whole calibration process, the reference tone signal that signal generator produces remains unchanged always, and all calibration computings all are to finish in digital receiver inside.Utilize this characteristics, can realize utilizing same signal generator to calibrate simultaneously a plurality of digital receivers.

Below introduce an application example that utilizes method of the present invention that a plurality of digital receivers are calibrated simultaneously.

Please refer to Fig. 5, the system that a plurality of receivers is carried out simultaneously local oscillating frequency inceptive error calibrating mainly is made up of main control system, signal generator, power divider, calibration frock and digital receiver to be calibrated.Signal generator is used for producing calibration reference signal S _Ref, S _RefEnter into digital receiver through behind the power divider.Main control system is mainly used to the operating state of control-signals generator, and the control figure receiver starts and stop work such as calibration process and calibration data storage.

The calibration process of multi-receiver can be divided into station detection, enabling signal generator, calibration process, four steps of storage substantially.

Station detects: the station testing process mainly is to judge whether each station has digital receiver to be calibrated to exist, and the information such as frequency information of reference signal are sent to digital receiver, so that digital receiver is realized the calculating of local oscillation signal frequency.

The enabling signal generator: the enabling signal generator mainly is a main control system configuration signal generator, makes it produce the required reference signal S of calibration _Ref

Calibration process: after signal generator entered normal operating conditions, main control system can notify digital receiver to begin the frequency calibration process.After calibration process finished, receiver just can send to main control system to the data of calibration acquisition, wait for then main control system instruction.Main control system can be judged the validity of this calibration data according to historical data, thereby determines next step action.

Storage:, just can notify receiver to store the data of this calibration if main control system thinks that this calibration data is effective after checking.

Should be noted that at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spiritual scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (7)

1. the method for a digital receiver local oscillating frequency inceptive error calibrating is characterized in that, comprises the steps:

A, utilize signal generator to produce, and output to described digital receiver with reference to tone signal;

B, described digital receiver are with local oscillation signal and describedly carry out mixing with reference to tone signal, mixed frequency signal is carried out the low-pass filtering post-sampling, and sampled signal is carried out Fourier transform, obtain the digital baseband signal frequency;

C, according to described digital baseband signal frequency with reference to the tone signal frequency, calculate the local oscillation signal frequency;

D, carry out local oscillating frequency inceptive error calibrating according to described local oscillation signal frequency and local oscillation signal nominal frequency;

Among the described step C, in reference tone signal frequency during greater than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, wherein, f _oBe local oscillation signal frequency, f _RefBe reference tone signal frequency,

Be the local oscillation signal nominal frequency,

Be the digital baseband signal frequency.

2. the method for claim 1 is characterized in that:

When the frequency error coefficient k _ErrBe far smaller than at 1 o'clock, among the then described step C, in reference tone signal frequency during greater than the local oscillation signal frequency, according to Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to Calculate the local oscillation signal frequency, wherein, $k_{\mathrm{err}}=\frac{f_o-{\stackrel{\&OverBar;}{f}}_o}{{\stackrel{\&OverBar;}{f}}_o}.$

3. the method for claim 1 is characterized in that, described step D specifically comprises:

According to

Calculate the FREQUENCY CONTROL coefficient, wherein, k is the FREQUENCY CONTROL coefficient, f _{O, c1}Be frequency control word c ₁Corresponding local oscillation signal frequency, f _{O, c2}Be frequency control word c ₂Corresponding local oscillation signal frequency, c ₁, c ₂Be two frequency control words that are provided with in the calibration process;

According to Calculate the frequency control word of local oscillation signal nominal frequency correspondence, wherein,

Be the frequency control word of local oscillation signal nominal frequency correspondence,

Be the local oscillation signal nominal frequency, [] is rounding operation;

The frequency control word of described local oscillation signal nominal frequency correspondence is preserved, when starting, the frequency control word of described local oscillation signal nominal frequency correspondence is carried out producing after the digital-to-analogue conversion control voltage of oscillator for described digital receiver.

4. the method for claim 1 is characterized in that:

In the described steps A, describedly further output to a plurality of digital receivers by power divider with reference to tone signal.

5. a digital receiver comprises voltage controlled oscillator, frequency mixer, low pass filter, analog to digital converter, Fourier transformer, digital to analog converter, it is characterized in that, also comprises local oscillation signal frequency calculator, error corrector device, wherein:

Voltage controlled oscillator is used to produce local oscillation signal;

Frequency mixer is used to receive the reference tone signal of local oscillation signal and signal generator output, and carries out mixing with local oscillation signal with reference to tone signal;

Low pass filter is used for mixed frequency signal is carried out low-pass filtering;

Analog to digital converter is used for filtered signal is sampled;

Fourier transformer is used for sampled signal is carried out Fourier transform, obtains the digital baseband signal frequency;

The local oscillation signal frequency calculator is used for calculating the local oscillation signal frequency according to the digital baseband signal frequency with reference to the tone signal frequency;

Error corrector device is used for carrying out local oscillating frequency inceptive error calibrating according to local oscillation signal frequency and local oscillation signal nominal frequency;

Digital to analog converter, the frequency control word that is used for that calibration is obtained carries out producing control voltage of voltage-controlled oscillator after the digital-to-analogue conversion;

Described local oscillation signal frequency calculator is further used for:

In reference tone signal frequency during greater than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, wherein, f _oBe local oscillation signal frequency, f _RefBe reference tone signal frequency,

Be the local oscillation signal nominal frequency,

Be the digital baseband signal frequency.

6. digital receiver as claimed in claim 5 is characterized in that, when the frequency error coefficient k _ErrBe far smaller than at 1 o'clock, then described local oscillation signal frequency calculator is further used for:

In reference tone signal frequency during greater than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, in reference tone signal frequency during less than the local oscillation signal frequency, according to

Calculate the local oscillation signal frequency, wherein,

7. digital receiver as claimed in claim 5 is characterized in that, described error corrector device is further used for:

According to Calculate the FREQUENCY CONTROL coefficient, wherein, k is the FREQUENCY CONTROL coefficient, f _{O, c1}Be frequency control word c ₁Corresponding local oscillation signal frequency, f _{O, c2}Be frequency control word c ₂Corresponding local oscillation signal frequency, c ₁, c ₂Be two frequency control words that are provided with in the calibration process;

According to Calculate the frequency control word of local oscillation signal nominal frequency correspondence, wherein,

Be the frequency control word of local oscillation signal nominal frequency correspondence,

Be the local oscillation signal nominal frequency, [] is rounding operation.

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