CN101106413A - A generation method and device of highly stable local reference signal for TDD shift frequency repeater - Google Patents

Abstract

The invention provides a method and a means for generating a highly stable local reference signal of the TDD frequency shift repeater. The method includes the step: by using the clock calibration pulse generated after GPS synchronization, digital frequency discrimination is performed on the local reference signal, and the frequency estimation sample output by frequency discrimination is digital-averagingly filtered to generate the frequency estimation parameter; the error correction control parameter is combined with the present test quantity of environmental temperature, and then transformed to an analog signal output; after the process of analog low-pass filtering, the analog signal is used to control the work frequency of the voltage-adjusting crystal oscillator to finally realize the closed-loop control adjustment of the local reference signal frequency. The means comprises a voltage-adjusting crystal oscillator, a digital frequency discriminator, a temperature sensor, a nonvolatile temperature parameter storage panel, a digital averaging filter and controller, a digital quantity-to-analog signal converter, an analog low-pass filter, a local reference signal frequency divider, a local reference signal output driver, and frequency divider sequential counting means.

Description

A kind of highly stable local reference signal production method and device that is used for the TDD frequency-shift repeater

Technical field

The present invention relates to the production method and the device of the local reference clock of a kind of high stability; particularly a kind of TDD (Time-Duplex Division) frequency-shift repeater field that is used for; calibration pulse on the GPS star is combined with the digital-to-analogue mixed signal treatment technology, to produce the method and apparatus of high accuracy, high long-term stability and low local reference signal (the Local Oscillator) that make an uproar mutually.

Background technology

The TDD mobile communication system does not need paired frequency planning, promptly can provide high spectrum utilization and SM, and at present domestic have mainly comprising of sizable application following three kinds of standard: PHS, SCDMA and TD-SCDMA.Consider the characteristics of tdd mode time-division work, whole mobile communications network must guarantee that strict timing is synchronous, to reduce internal interference; Above-mentioned three kinds of systems all adopt mode such as GPS regularly unified to the equipment of the whole network.

Mobile network's base station signal in above-mentioned three kinds of systems is subjected to barrier zones, and operator generally adopts various forms of network optimization equipment to replenish covering.Adopt down-conversion and up-conversion mode to carry out the network optimization equipment of signal relay for needs, must adopt high steady accuracy (being better than 0.1ppm), low local reference source of making an uproar mutually to use for Radio Frequency Subsystem.Scheme commonly used at present is to adopt expensive OCXO device, so that the pure sine wave signal of high steady accuracy to be provided.

The TDD mode of operation also proposes new requirement to the Radio Frequency Subsystem control of network optimization equipment, and the transmitting-receiving bidirectional amplifier unit of network optimization equipment must satisfy strict sequential relationship, just can avoid occurring self-excitation, degradation and the damage of equipment.Adopt GPS as the reference benchmark, can reliably produce Radio Frequency Subsystem sending and receiving control timing signal, and make things convenient for timing and phase configuration between each control timing.

Calibration pulse on the star of GPS back output synchronously, general frequency is lower, and the cycle is 1 second or hundreds of millisecond, and has still comprised the randomized jitter of introducing owing to synchronous error in this calibration pulse.The method of the local reference source of traditional generation is to utilize phase-locked loop (PLL), but carries out frequency multiplication and produce the control timing signal and the common local reference source signal of 12.8MHz is difficult to realize for several hertz to tens hertz signal.The calibration pulse of certain model GPS output higher frequency comprises all kinds of common digital noises and crosstalks, and also is difficult to use as other any type of analog references source signals.

The crystal oscillator of commercial cheapness has extraordinaryly makes an uproar mutually, but frequency accuracy is generally 10～100ppm scope.The TCXO device that is very easy to obtain can reach the 1ppm rank in very narrow temperature range, but, still can not satisfy above-mentioned TDD frequency-shift repeater application requirements for-40 ℃～+ 60 ℃ working ranges of outdoor version equipment and the cycle of operation life of product condition in 3 ~ 5 years.Can in the cycle of operation life of product more than 3 years, satisfy the optional scope of OCXO device that steady accuracy requires and remain limited.

The invention overview

The present invention seeks to develop a kind of solving the problems of the technologies described above, the existing demand of comprehensive TDD frequency-shift repeater provides a kind of highly stable local reference signal production method and device of the TDD of being used for frequency-shift repeater.

The technology used in the present invention method comprises following steps:

(1) digital frequency discriminator is sent in the output of GPS calibration pulse and this ground voltage adjustment crystal oscillator, obtains the Frequency Estimation sampled point of local reference source signal.

(2) the Frequency Estimation sampled point of digital frequency discriminator output by digital filtering after, obtain corresponding frequency error and estimate parameter.

(3) numerical control device is determined step-length, side-play amount and the scale factor of corresponding control output according to above-mentioned estimation parameter.

(4) this numeric field control output is converted into analog control signal by the DAC interface, delivers to the frequency adjustment end that this ground voltage is adjusted crystal oscillator after the low-pass filtering.

(5) above-mentioned 1～4 process repeats, and the output frequency of adjusting crystal oscillator until this ground voltage satisfies required precision.

(6) control parameter and the current environmental temperature after the current control loop convergence is updated into local nonvolatile storage clock open loop control parameter list.

(7) lose under the synchronous condition as GPS, digitial controller can utilize and obtain this ground voltage after the open loop control parameter list content interpolation of local nonvolatile storage and adjust crystal oscillator frequency and adjust control signal.

(8) after the control loop convergence, this ground voltage adjustment crystal oscillator output signal utilization transmitting-receiving control timing counting device produces the receipts that are used for Radio Frequency Subsystem and enables, sends out enable signal.

(9) after the control loop convergence, this ground voltage is delivered to Radio Frequency Subsystem as local reference source signal after adjusting the output signal process frequency divider and 50 ohmic drive devices of crystal oscillator.

Wherein, the external GPS calibration pulse is adjusted crystal oscillator output clock with this ground voltage and is sent into digital frequency discriminator simultaneously, and phase demodulation output is converted to the simulation Control Parameter through behind the digital filtering, realizes the closed loop frequency adjustment of this ground voltage adjustment crystal oscillator.

After the control loop convergence, adjusting the crystal oscillator clock with this ground voltage is the control counter of input, the output high-accuracy pulse dashes as Radio Frequency Subsystem sending and receiving control timing signal, this ground voltage is adjusted the output of crystal oscillator clock through after isolation, frequency division and the driving simultaneously, delivers to Radio Frequency Subsystem as the low radio frequency reference source signal of making an uproar mutually.

A kind of highly stable local reference signal generation device of the TDD of being used for frequency-shift repeater comprises: voltage is adjusted crystal oscillator (being called for short VCXO), digital frequency discriminator, temperature sensor, non-volatile temperature parameter storage list, digital mean filter and controller, digital quantity to analog signal converter (being called for short DAC), simulation low-pass filter (being called for short LPF), local reference signal frequency divider, local reference signal output driver and transmitting-receiving control timing counting device.

Wherein, it can be any support electrical quantity frequency trim crystal oscillator type that voltage is adjusted crystal oscillator, and frequency adjustment range should cover the intrinsic skew of possible crystal oscillator.

Digital frequency discriminator is the timing error that is used to take out between this ground voltage adjustment crystal oscillator output clock and the GPS calibration pulse, and with the random frequency drift error sampling that is converted in this timing error.

Temperature sensor can be any temperature parameter to be converted to the sensor type of voltage, electric current or resistance parameter, and working range should cover possible voltage and adjusts crystal oscillator temperature drift scope.

Non-volatile temperature parameter storage list can be anyly to satisfy the type of memory repeatedly wipe with rewriting operation, and its capacity should cover this possible ground voltage and adjusts the crystal oscillator operating temperature range.

Numeral mean filter and controller can be the adaptive algorithm implementation structures that any following type is used to reduce error signal: lowest mean square (LMS), recurrence lowest mean square (RLS) and Kalman filtering (Kalman).

Digital quantity to analog signal converter can be any form is converted to digital parameters aanalogvoltage, electric current and resistance parameter according to certain functional relation a way of realization.

Simulation low-pass filter should not produce appreciable impact to the time constant of mixing control loop when being used to produce level and smooth control signal.

The local reference signal frequency divider is used for the reduction input reference signal frequency of integral multiple, and keeps phase noise not produce deterioration.

The local reference signal output driver is used to satisfy the 50 ohms impedance match requirements of common radio frequency.

Transmitting-receiving control timing counting device produces accurate, configurable and repeatably radio-frequency receiving-transmitting control timing pulse by this ground voltage being adjusted crystal oscillator output frequency counting and being compared.

Enforcement via technical scheme of the present invention, can realize providing cheaply low and make an uproar mutually, the local reference source signal of high stability, duration of work in the gps signal existence, this this locality reference source signal can be kept good long-term stability and the precision in 3～5 years, under the synchronous exceptional condition of GPS short-term, this this locality reference source still can utilize the mode of open loop to keep the precision of short-term.

Via the enforcement of technical scheme of the present invention, can realize mixed and closed-loop control method cheaply, integrated sending and receiving control timing signal producing method is fit to multiple frequency needs.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 is a theory diagram of the present invention.

Fig. 2 is the theory diagram of digital frequency discriminator of the present invention.

Fig. 3 is the embodiment one of digital frequency discriminator of the present invention.

Fig. 4 is the embodiment two of digital frequency discriminator of the present invention.

Fig. 5 is digital filtering of the present invention and control device workflow diagram.

Fig. 6 is the specific embodiment one of TDD radio communication transmitting-receiving control timing waveform.

Fig. 7 is the specific embodiment two of TDD radio communication transmitting-receiving control timing waveform.

Embodiment

As shown in Figure 1, external GPS calibration pulse and voltage are adjusted crystal oscillator

The output clock is sent into simultaneously as Fig. 2, Fig. 3, digital frequency discriminator shown in Figure 4

, so that obtain the coarse frequency estimate of error that voltage is adjusted crystal oscillator.The enchancement factors such as order of accuarcy of the disturbance of the atmosphere that exists in the GPS implementation, the perturbation of satellite orbit and ephemeris cause desirable calibration pulse n * T time of advent of GPS _PpsOn be superimposed with at random shake t _Jitter ⁿ:

$t_{\mathrm{pps}}^n=n\×T_{\mathrm{pps}}+t_{\mathrm{jitter}}^n$

(1)

R wherein _Jitter ⁿShake for superposeing in current n the PPS calibration pulse shows as stochastic variable.Voltage is adjusted crystal oscillator Can be any support electrical quantity frequency trim crystal oscillator type, frequency adjustment range should cover the intrinsic skew of possible crystal oscillator.

Digital frequency discriminator

Purpose be to take out voltage to adjust crystal oscillator

Timing error between output clock and the GPS calibration pulse, and will be converted to voltage adjustment crystal oscillator in this timing error

Random frequency drift error sampling.This frequency error can separate to be based on adjusts crystal oscillator to voltage

The following consideration of frequency departure characteristic:

A) after reaching heat balance, voltage is adjusted crystal oscillator

The operating ambient temperature variation is drawn

The frequency drift of sending out is minute being unit;

B) after reaching stable state, voltage is adjusted crystal oscillator

Supply power voltage and inner direct current

The frequency drift that offset parameter causes is hour being unit;

C) under the continuous operation condition, voltage is adjusted crystal oscillator

Intrinsic aging phenomenon is drawn

The frequency drift of sending out is unit with the sky;

Fig. 2 provides desirable digital frequency discriminator model, and Fig. 3 and Fig. 4 provide two examples of specific implementation.

Utilize the delayer among Fig. 2

With current calibration pulse t _Pps ⁿTime-delay T _PpsBe t _Pps ^N-1, send into the E counter respectively

With the L counter The E counter

Become leading counter again, the L counter

Become hysteresis counter again.VCXO

The frequency of output is f _Lo ⁿSinusoidal signal through after the level conversion as the E counter

With the L counter

Clock use, thereby determined counter

With

Minimum resolution.Voltage is adjusted crystal oscillator

The output frequency parameter f _Lo ⁿBe stochastic variable, corresponding E counter Count value N _EWith the L counter

Count value N _LComputing formula is:

$N_E=t_{\mathrm{pps}}^n\×f_{\mathrm{lo}}^n=(n\×T_{\mathrm{pps}}+t_{\mathrm{fitter}}^n)\×f_{\mathrm{lo}}^n---\left(2\right)$

$N_L=t_{\mathrm{pps}}^{n-1}\×f_{\mathrm{lo}}^n=((n-1)\×T_{\mathrm{pps}}+t_{\mathrm{jitter}}^{n-1})\×f_{\mathrm{lo}}^n---\left(3\right)$

The E counter With the L counter

Realization can adopt arbitrarily synchronously or the asynchronous counter form, be example with common binary counter, key design parameter is counting bit wide and maximum clock frequency.Adopt common digital logic device, above-mentioned counter works clock frequency can reach 100MHz easily; Adopt universal counter parts and support software, above-mentioned counter works frequency can be easy to reach 20MHz.

The distance calculation parts of Fig. 2 Be used for calculating

With

The difference of count results, thus each of average GPS estimates that pulse period can calculate a sampled value of Frequency Estimation.The distance calculation parts

It should be the difference computing under the integer delivery condition.The distance calculation parts

Operational precision depend primarily on voltage and adjust crystal oscillator The operating frequency and the ratio in GPS calibration pulse cycle.Utilize the distance calculation parts Can obtain voltage and adjust crystal oscillator Current output frequency f when n GPS estimates that pulse arrives _Lo ⁿEstimation sampling

F _Sample ⁿ:

$F_{\mathrm{sample}}^n=N_E^n-N_L^n$

$=t_{\mathrm{pps}}^n\×f_{\mathrm{lo}}^n-t_{\mathrm{pps}}^{n-1}\×f_{\mathrm{lo}}^n---\left(4\right)$

But the desirable delayer T among Fig. 2 _PpsCan't realize, can only adjust crystal oscillator by adopting voltage in the specific implementation Output frequency to T _PpsEstimate.

Fig. 3 scheme is the work-around solution under Fig. 2 principle, output be that n GPS frequency error when estimating that pulse arrives is estimated sampling F _Ernor ⁿTime-delay trigger wherein

Utilize local reference clock to produce prediction pulse with GPS calibration pulse width, logic ' with ' computing

Be used to calculate the phase difference between gps time calibration pulse and the local prediction pulse, this phase difference performance is the time width of output pulse.Utilize local reference clock through frequency multiplication

Output is as clock, the E counter

GPS calibration pulse phase difference can be converted to the count value of corresponding temporal resolution, this count value can be thought the frequency error sampling

F _Ernor ⁿ

Fig. 4 scheme is that the directly approximate of Fig. 2 scheme realized, can adjust crystal oscillator by output voltage

Frequency Estimation sampling

Coincidence counter Local reference clock is counted N synchronously ⁿ, shift register L

On the function with Fig. 2 scheme in the L counter

Quite, shift register E

On the function with Fig. 2 scheme in the E counter

Quite, distance calculation

With Fig. 2 scheme middle distance calculating unit Function identical.The Frequency Estimation sampling f of Fig. 4 scheme output _Sample ⁿBe the F of Fig. 2 scheme _Sample ⁿA kind of approximate:

$f_{\mathrm{sample}}^n=N^n-N^{n-1}$

$=t_{\mathrm{pps}}^n\×f_{\mathrm{lo}}^n-t_{\mathrm{pps}}^{n-1}\×f_{\mathrm{lo}}^{n-1}---\left(5\right)$

Below we still with digital frequency discriminator

Fig. 2 ideal model describe.Can calculate digital frequency discriminator easily

The Frequency Estimation sampling F of output _Sample ⁿDesired value be:

$E\left\{F_{\mathrm{sample}}^n\right\}=E\{(n\×T_{\mathrm{pps}}+t_{\mathrm{jitter}}^n)\×f_{\mathrm{lo}}^n-((n-1)\×T_{\mathrm{pps}}+t_{\mathrm{jitter}}^{n-1})\×f_{\mathrm{lo}}^n\}$

$=T_{\mathrm{pps}}\×E\left\{f_{\mathrm{lo}}^n\right\}+E\{t_{\mathrm{jitter}}^n\×f_{\mathrm{lo}}^n\}-E\{t_{\mathrm{jitter}}^{n-1}\×f_{\mathrm{lo}}^n\}---\left(6\right)$

Consider stochastic variable t _Jitter ⁿAnd f _Lo ⁿStatistics is independent, and t _Jitter ⁿThe irrelevant characteristic of time of average:

$E\left\{F_{\mathrm{sample}}^n\right\}=T_{\mathrm{pps}}\×E\left\{f_{\mathrm{lo}}^n\right\}$

(7)

From formula (7) Frequency Estimation sampling F as can be seen _Sample ⁿ

Be frequency parameter f _Lo ⁿNothing estimate partially.This does not have the calculating of estimating partially can pass through digital mean filter and control device

Digital mean filter function realize digital mean filter and control device

Digital mean filter function can by the structure following frequency estimator F _Fine ^MComputational methods realize:

$F_{\mathrm{fine}}^M=\frac{1}{M}\underset{n=0}{\overset{M-1}{\mathrm{\Σ}}}{F}_{\mathrm{sample}}^n$

$=\frac{1}{M}\underset{n=0}{\overset{M-1}{\mathrm{\Σ}}}(N_E^n-N_L^n)---\left(8\right)$

$=\frac{1}{M}\underset{n=0}{\overset{M-1}{\mathrm{\Σ}}}\{T_{\mathrm{pps}}\×f_{\mathrm{lo}}^n+t_{\mathrm{jitter}}^n\×f_{\mathrm{lo}}^n-t_{\mathrm{jitter}}^{n-1}\×f_{\mathrm{lo}}^n\}$

F _Fine ^MCalculating relate to the selection of algorithm filter parameter, the selection of M is based on stochastic variable f _Lo ⁿFurther decompose: slow drift component and the high dither component that changes.In the Measuring Time of M correspondence, stochastic variable f _Lo ⁿSlowly variation should not surpass the convergence error of final closed-loop control; And high dither component and voltage are adjusted crystal oscillator

Make an uproar mutually relevant, the resolving range that can detect well below this programme, thereby can not consider.Numeral mean filter and control device

Digital mean filter method purpose be to separate the intrinsic randomized jitter of GPS calibration pulse and voltage and adjust crystal oscillator

Output frequency is at digital frequency discriminator

Slowly drift at random under the apparent resolution.

F _Fine ^MEstimation precision depend on the selection of M, and bigger M can cause slow closed-loop control response time and better estimated accuracy.Do not wish that better estimated accuracy is arranged if do not wish to select bigger M value, can improve digital frequency discriminator

Operating frequency to K doubly, and make frequency divider

Output frequency identical with expected frequency.Under identical estimated accuracy condition, the equivalent theory conversion relation between K and the M is as follows:

$K=\sqrt{M}$

(9)

Adjust crystal oscillator according to the current voltage that calculates

Output frequency estimated value F _Fine ^MAnd the error between the desirable output frequency is poor, digital mean filter and control device among Fig. 1

Control device can adopt known any feedback control algorithm determine to reduce the required control output of this error.Utilize digital quantity to analog signal converter

Digital quantity to the analog signal conversion function, can be with digital mean filter and control device

The controlled quentity controlled variable finally determined of control device be output as analog signal.This analog signal is through simulation low-pass filter Low-pass filtering after, be used for level and smooth control voltage and adjust crystal oscillator

Frequency adjustment end.

Adjust crystal oscillator according to current voltage Closed loop frequency adjust result, digital mean filter and control device

The step-length and the scale factor of control device output controlled quentity controlled variable be variable so that satisfy convergence and low-residual error fast simultaneously.

Digital quantity is to analog signal converter Output should satisfy voltage and adjust crystal oscillator Direct current biasing point, dynamic range, resolution and response speed that frequency adjustment control is required.Digital quantity is to analog signal converter

The direct current biasing point of output should be positioned at voltage and adjust crystal oscillator

The central point V of frequency adjustment control _Middle, dynamic range should satisfy the actual frequency deviation range, and voltage resolution should satisfy frequency and adjust required precision.For guaranteeing effective convergence of frequency correction loop, digital quantity is to analog signal converter in addition Curve of output also must be dull and can not lose sign indicating number; Voltage is adjusted crystal oscillator

Frequency to adjust curve also must be dull.

Digital quantity is to analog signal converter

Dynamic range V _Fullscale, bit wide N and minimum explanation voltage Δ should satisfy following relation: V _Fullscale=V _Middle± 2 ^N-1* Δ (10)

Numeral mean filter and control device Control device adjust crystal oscillator detecting voltage

After output frequency is in the 0.1ppm convergence range and keeps a period of time, reading temperature sensor

The current environmental temperature parameter, and will be with it corresponding current Control Parameter and be updated into local nonvolatile parameters storage list

In.The device of Fig. 2 does not have calibration pulse when output, digital mean filter and control device when the GPS step-out occurring in normal course of operation

Control device can utilize the nonvolatile parameters storage list

In the voltage that causes of the following short-term factor of sample point open-loop compensation adjust crystal oscillator

Output frequency changes:

A) voltage is adjusted crystal oscillator

Power supply varies with temperature and the frequency error that causes;

B) voltage is adjusted crystal oscillator Variation of ambient temperature and the frequency error that causes;

Open-loop compensation characteristic of the present invention makes final products possess a kind of short duration failure robust property, local nonvolatile parameters storage list under long-term continuous operation condition

The learning data of middle accumulation is many more, can tolerate the GPS fault of longer time more.But adjust crystal oscillator for voltage

The long-term frequency shift (FS) phenomenon that wears out and cause of using, this open-loop method is restricted, and the use that must combine with the closed loop mode of operation of routine.

Frequency divider among Fig. 1 Be optional function, higher digital frequency discriminator work clock can support further to improve the precision of closed loop frequency calibration.But comprise the spuious and low order harmonics composition of more near-end in the output spectrum of digital frequency division, need careful design to use as the local reference source of some TDD type Radio Frequency Subsystem.

Driver among Fig. 1 Should possess high input resistance and low output impedance characteristic, consider and the impedance matching requirement of Radio Frequency Subsystem that output impedance should be 50 ohm.

Transmitting-receiving control timing counting device among Fig. 1

Characteristics be to utilize the voltage among the present invention to adjust crystal oscillator

Output clock and general binary counter able to programme produce the control impuls width and the phase place that become the integral multiple relation with TDD mobile communication bottom character rate.Transmitting-receiving control timing counting device

Can produce the sending and receiving passage that is used for the TDD Radio Frequency Subsystem and enable control signal, also can produce the Transmitter Turn-Off signal that satisfies the spuious requirement of frequency spectrum.The distinctive time domain transmitting power template control of corresponding TDD mobile communication system physical layer standard, transmitting-receiving control timing counting device

Can be used for corresponding gain control loop startup, reset and sequencing control.

Fig. 6 provides the transmitting-receiving control timing counting device output waveform example of a kind of typical TDD radio communication standard SCDMA.The physical layer symbol rate of SCDMA is 409.6Kbps, and the voltage of employing is adjusted crystal oscillator

The nominal output frequency is 12.8MHz, and base station sending and receiving frame width is 5 milliseconds, the protection time slot

Width is 390.625 microseconds.

Receiving frame count value=5ms * 12.8MHz=64000 (11)

Protection time slot count value=390.625us * 12.8MHz=5000 (12)

The sending and receiving enable signal pulse duration counting that formula (9) is corresponding

With receipts enable signal pulse duration counting

Can very easily adopt the combination of 16 binary counters and digital comparator to realize.The protection time slot that formula (10) is corresponding

Count value can adopt 13 binary counters and digital comparator combination to realize.The control timing signal timing precision that adopts the method to obtain is better than

Spreading rate.

Fig. 7 provides the transmitting-receiving control timing counting device output waveform example of a kind of typical TDD radio communication standard TD-SCDMA.The physical layer symbol rate of TD-SCDMA is 1.28Mbps, selects voltage to adjust crystal oscillator The nominal output frequency is 12.8MHz.As can be seen, because voltage is adjusted crystal oscillator

The nominal output frequency becomes the integral multiple relation with the TD-SCDMA physical layer symbol rate, simplified the realization of sending and receiving enable signal counter, and control timing signal timing precision is

Spreading rate.

Local reference frequency with 12.8MHz is an example, design of the present invention frequency stability when-40 ' C ~+80 ' C working range operation with closed ring is better than 0.01ppm/24 hour, the life cycle of operation of entire product can realize with the GPS star on the long-term stability that is complementary of clock.Voltage is adjusted crystal oscillator

The local reference source signal that exports Radio Frequency Subsystem after output drives to is made an uproar mutually and is better than-130dBc/Hz@1KHz offset.

The product of realizing based on the present invention is by configuration software, hardware operational factor with select different nominal frequency voltages to adjust crystal oscillators

Device, can satisfy the TDD microwave repeater application demand between 1MHz ~ 100MHz easily.

Technical scheme of the present invention is stable and reliable for performance, long service life, and cost is low, and market prospects are good.

Claims (9)

1. a highly stable local reference signal production method that is used for the TDD frequency-shift repeater may further comprise the steps:

(1) digital frequency discriminator is sent in the output of GPS calibration pulse and this ground voltage adjustment crystal oscillator, obtains the Frequency Estimation sampled point of local reference source signal.

(2) the Frequency Estimation sampled point of digital frequency discriminator output by digital filtering after, obtain corresponding frequency error and estimate parameter.

(3) numerical control device is determined step-length, side-play amount and the scale factor of corresponding control output according to above-mentioned estimation parameter.

(4) this numeric field control output is converted into analog control signal by the DAC interface, delivers to the frequency adjustment end that this ground voltage is adjusted crystal oscillator after the low-pass filtering.

(5) above-mentioned 1～4 process repeats, and the output frequency of adjusting crystal oscillator until this ground voltage satisfies required precision.

(6) control parameter and the current environmental temperature after the current control loop convergence is updated into local nonvolatile storage clock open loop control parameter list.

(7) lose under the synchronous condition as GPS, digitial controller can utilize and obtain this ground voltage after the open loop control parameter list content interpolation of local nonvolatile storage and adjust crystal oscillator frequency and adjust control signal.

(8) after the control loop convergence, this ground voltage adjustment crystal oscillator output signal utilization transmitting-receiving control timing counting device produces the receipts that are used for Radio Frequency Subsystem and enables, sends out enable signal.

(9) after the control loop convergence, this ground voltage is delivered to Radio Frequency Subsystem as local reference source signal after adjusting the output signal process frequency divider and 50 ohmic drive devices of crystal oscillator.

2. a kind of highly stable local reference signal production method that is used for the TDD frequency-shift repeater according to claim 1, it is characterized in that described GPS calibration pulse and this ground voltage adjust crystal oscillator output clock and send into digital frequency discriminator simultaneously, phase demodulation output is converted to the simulation Control Parameter through behind the digital filtering, realizes the closed loop frequency adjustment of this ground voltage adjustment crystal oscillator.

3. a kind of highly stable local reference signal production method that is used for the TDD frequency-shift repeater according to claim 1, after it is characterized in that described control loop convergence, adjusting the crystal oscillator clock with this ground voltage is the control counter of input, the output high-accuracy pulse dashes as Radio Frequency Subsystem sending and receiving control timing signal, this ground voltage is adjusted the output of crystal oscillator clock through after isolation, frequency division and the driving simultaneously, delivers to Radio Frequency Subsystem as the low radio frequency reference source signal of making an uproar mutually.

4. a highly stable local reference signal generation device that is used for the TDD frequency-shift repeater comprises: voltage is adjusted crystal oscillator, digital frequency discriminator, temperature sensor, non-volatile temperature parameter storage list, digital mean filter and controller, digital quantity to analog signal converter, simulation low-pass filter, local reference signal frequency divider, local reference signal output driver and transmitting-receiving control timing counting device.

Wherein, it can be any support electrical quantity frequency trim crystal oscillator type that voltage is adjusted crystal oscillator, and frequency adjustment range should cover the intrinsic skew of possible crystal oscillator.

Temperature sensor can be any temperature parameter to be converted to the sensor type of voltage, electric current or resistance parameter, and working range should cover possible voltage and adjusts crystal oscillator temperature drift scope.

Non-volatile temperature parameter storage list can be anyly to satisfy the type of memory repeatedly wipe with rewriting operation, and its capacity should cover this possible ground voltage and adjusts the crystal oscillator operating temperature range.

Numeral mean filter and controller can be the adaptive algorithm implementation structures that any following type is used to reduce error signal: lowest mean square (LMS), recurrence lowest mean square (RLS) and Kalman filtering (Kalman).

Digital quantity to analog signal converter can be any form is converted to digital parameters aanalogvoltage, electric current and resistance parameter according to certain functional relation a way of realization.

5. a kind of highly stable local reference signal generation device that is used for the TDD frequency-shift repeater according to claim 4, it is characterized in that described digital frequency discriminator is the timing error that is used to take out between this ground voltage adjustment crystal oscillator output clock and the GPS calibration pulse, and with the random frequency drift error sampling that is converted in this timing error.

6. a kind of highly stable local reference signal generation device that is used for the TDD frequency-shift repeater according to claim 4, it is characterized in that described simulation low-pass filter when being used to produce level and smooth control signal, should not produce appreciable impact the time constant of mixing control loop.

7. a kind of highly stable local reference signal generation device that is used for the TDD frequency-shift repeater according to claim 4, it is characterized in that described local reference signal frequency divider is used for the reduction input reference signal frequency of integral multiple, and keep phase noise not produce deterioration.

8. a kind of highly stable local reference signal generation device that is used for the TDD frequency-shift repeater according to claim 4 is characterized in that described local reference signal output driver is used to satisfy the 50 ohms impedance match requirements of common radio frequency.

9. a kind of highly stable local reference signal generation device that is used for the TDD frequency-shift repeater according to claim 4, it is characterized in that described transmitting-receiving control timing counting device by this ground voltage being adjusted crystal oscillator output frequency counting and being compared, produces accurate, configurable and repeatably radio-frequency receiving-transmitting control timing pulse.

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