CN101369171A - Method and apparatus for acquiring searched word - Google Patents
Method and apparatus for acquiring searched word Download PDFInfo
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- CN101369171A CN101369171A CNA2008100438415A CN200810043841A CN101369171A CN 101369171 A CN101369171 A CN 101369171A CN A2008100438415 A CNA2008100438415 A CN A2008100438415A CN 200810043841 A CN200810043841 A CN 200810043841A CN 101369171 A CN101369171 A CN 101369171A
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Abstract
The invention discloses a lookup word acquisition device, comprising a data storage unit and a lookup word lock unit. The data storage unit is used to store initial data obtained through sampling analysis to an ideal lookup curve at a predetermined lookup interval, and the initial data include lookup words corresponding to initial lookup points. The lookup word lock unit is used for acquiring lookup words corresponding to computation lookup points according to the initial data, and the computation lookup points are lookup points that successively approach to the current lookup points until entering the predetermined locking range of the current lookup points from the initial lookup points by taking the predetermined lookup interval as a step length, and the lookup words corresponding to computation lookup points are output when the computation lookup points enter the predetermined locking range of the current lookup points. So the data memory capacity can be maximally reduced, and the precision of temperature frequency compensation can also be improved.
Description
Technical field
The present invention relates to the COMPUTER CALCULATION field, particularly successive approximation is searched word acquisition methods and device.
Background technology
Can both be normally or synchronous working in order to ensure all electron devices, it is very important that accurate clock signal is provided in design of electronic circuits.Usually, described clock signal is generally can be produced by crystal oscillator (crystal oscillator), and wherein said crystal oscillator is to utilize the mechanical resonant of the oscillating crystal of piezoelectric to produce the electronic circuit of certain frequency electric signal.A reason that causes clock signal to be different from design is temperature, and it may influence the running of piezoelectric and crystal oscillator.Along with variation of temperature, the frequency of crystal oscillator output can also can change thereupon.In fact, electronic equipment may be used to such as portable computer, mobile phone and electronic instrument therefore guarantee that these electronic equipments can both normally errorless work be very important under all temps environment in the environment of all temps variation.
Many modern communications equipments need the frequency of high precision, high stable to increase the sensitivity of radio transceiver in it such as GPS and gsm system and reduce collection/tracking time.Yet the output of crystal oscillator again and again can be drifted about along with life-span and variation of temperature, and common crystal oscillator can not provide yet and suppresses the mechanism that crystal frequency changes with environment temperature.Because harsh demand, it is impossible using low-cost independent crystal oscillator in the cellular system from the frequency tuning support of base station not.
The frequency source of wireless telecommunications system or mobile phone includes digitally controlled crystal oscillator (digitallycontrolled crystal oscillator).Yet the digitally controlled crystal oscillator circuit need be introduced capacitor array and carry out frequency correction in crystal oscillator.Like this, use digitally controlled crystal oscillator just to become very expensive, especially for the digitally controlled crystal oscillator of deep-submicron COMS technology.In addition, cause frequency hopping effect (frequency beating effects) possibly, thereby be difficult to satisfy the requirement of output frequency stability by the output frequency of the switching of a large amount of electric capacity in the digitally controlled crystal oscillator being adjusted crystal oscillator.
In addition, described digitally controlled crystal oscillator circuit also needs the numerical control input signal to compensate the frequency drift that is changed and caused by temperature.Generally all adopt the frequency compensation of some discrete temperature spot correspondences of storage to be worth method, i.e. look-up table (Look-up table) method in the prior art.When needs carry out temperature frequency compensation, only the frequency compensation value of Current Temperatures correspondence directly need be taken out use just passable.Yet,, may have influence on the compensation effect of total system if obvious saltus step takes place frequency between some temperature spots.For the problems referred to above, a kind of solution is can utilize to adopt the mode of interpolation to overcome between the temperature interval, but this more complicated and compensation precision that hardware design is become may be poor.Another kind of solution is to reduce the frequency compensation value of temperature interval with the more temperature spot correspondences of acquisition, but this will increase the capacity of the storer that is used for the storing frequencies offset, also can increase the test point quantity of temperature frequency simultaneously.
In other physical application field, also use the look-up table method to obtain an a certain value of searching of correspondence of searching through regular meeting, also can run into same problem this moment, i.e. the memory space of look-up table and search contradictory problems between the precision.Therefore, demand urgently proposing a kind of memory capacity low, search accurately high successive approximation and search word and obtain technology.
Summary of the invention
In view of this, one of technical matters that the present invention solves is to provide a kind of word deriving means of searching, and it can utilize minimum memory capacity to find and search word accurately.
Two of the technical matters that the present invention solves is to provide a kind of word acquisition methods of searching, and it can utilize minimum memory capacity to find and search word accurately.
In order to address the above problem, according to an aspect of the present invention, the invention provides a kind of word deriving means of searching, be used to find the current word of searching of searching a correspondence, it comprises: data storage cell, be used to store ideal is searched curve with the predetermined primary data of carrying out sampling analysis at interval and obtaining of searching, described primary data comprises initially searches searching word, fixed step size and storing the fixed step size symbol table of some sign bits of fixed step size of a correspondence; Search letter lock order unit, be used for according to described primary data and before interim result data obtain to calculate and search the word of searching of a correspondence, to such an extent as to described calculating is searched a little with corresponding and is searched the formed matched curve of word and can search curve along described ideal and approach described current searching a little one by one from initially searching to light, it a little is to be spaced apart step-length and constantly a little to approach until entering current the searching a little of a little predetermined lock-in range of searching to current searching one by one from initially searching to light with described predetermined searching that described calculating is searched, interim result data is searched the calculating of having obtained before when a little not entering current predetermined lock-in range of searching a little and is searched the word of searching of a correspondence for calculating before described, and searches in described calculating and to export the word of searching that a correspondence is searched in described calculating when a little entering described current predetermined lock-in range of searching a little.
Further, search searching before the word of a correspondence, also need it is carried out interpolation processing to obtain the accurate current word of searching of searching a correspondence in the described calculating of output.
Further, described according to described primary data and before interim result data obtain and calculate the word of searching of searching a correspondence and comprise: from the fixed step size symbol table, obtain current calculating and search and a little approach next calculating and search the some sign bit of needed fixed step size, it a little is to search a little towards described current searching from current calculating a little to step nearly one and predeterminedly search calculating at interval and search a little that described next calculating is searched, and described current calculating is searched a little initial value for initially searching a little; Giving fixed step size with the sign bit that obtains searches and a little approaches described next calculating and search a little needed actual step size to obtain current calculating; Utilize current calculating search a correspondence search word and actual step size obtains the word of searching that a correspondence is searched in described next calculating; Described next calculating searched a little search a little and repeat aforesaid operations as the new current calculating of lower whorl.
Further, the ideal temperature frequency characteristic is carried out sampling analysis at interval and comprises with predetermined searching: a selected sampling is searched a little to initially searching a little, and the sampled value of searching a correspondence according to this sampling of selecting calculates the word of searching of initially searching a correspondence; Search the value that a little sampled value calculates each sign bit in described fixed step size, the fixed step size symbol table according to each sampling.
According to an aspect of the present invention, the invention provides a kind of word acquisition methods of searching, be used to find the current word of searching of searching a correspondence, it comprises: at interval ideal is searched curve and carry out sampling analysis and obtain primary data with predetermined searching, described primary data comprise initially search a correspondence search word, fixed step size and fixed step size symbol table, described fixed step size symbol table records the sign bit that the fixed step size of a correspondence is searched in each sampling; According to described primary data and before interim result data calculate from initially search light with predetermined search be spaced apart step-length constantly to current search a little to approach until being locked in current calculating of searching preset range a little search the word of searching of a correspondence, to such an extent as to described calculating is searched a little with corresponding and is searched the formed matched curve of word and can search curve along described ideal and approach described current searching a little one by one from initially searching to light, described before interim result data search the calculating that a non-locking obtained when the current preset range of searching a little and search the word of searching of a correspondence for calculating; Search when a little being locked in the described current preset range of searching some the word interpolation of searching of searching a correspondence in described calculating and obtain the described current word of searching of searching a correspondence according to described calculating.
Further, the described predetermined size at interval of searching is different with the difference of seek scope.
Further, be different seek scope settings on the same group primary data not, every group of primary data is corresponding to the seek scope of each self application.
Further, described according to described primary data and before interim result data calculate from initially search light with predetermined search be spaced apart step-length constantly to current search a little to approach until being locked in current calculating of searching preset range a little search the word of searching of a correspondence and comprise: from the fixed step size symbol table, obtain current calculating and search and a little approach next calculating and search the some sign bit of needed fixed step size, it a little is to search a little towards described current searching from current calculating a little to step nearly one and predeterminedly search calculating at interval and search a little that described next calculating is searched, and the initial value that described current calculating is searched a little is an initial temperature; Giving fixed step size with the sign bit that obtains searches and a little approaches described next calculating and search a little needed actual step size to obtain current calculating; Utilize current calculating search a correspondence search word and actual step size obtains the word of searching that a correspondence is searched in described next calculating; Described next calculating searched a little search a little and repeat aforesaid operations and search until current calculating and a little be locked in the current preset range of searching a little as the new current calculating of lower whorl.
Further, describedly ideal is searched curve carry out sampling analysis at interval and comprise with predetermined searching: the theory of utilizing each sampling of the sampling value of searching calculating to search is a little searched word; A selected sampling is searched a little to initially searching a little, and to search word be exactly the word of searching of initially searching a correspondence to this sampling theory of searching a correspondence so; The theory of searching a correspondence according to each sampling is searched first order difference, second order difference or the third order difference of word and is determined described fixed step size; According to the fixed step size of determining, initially search word and each sampling of searching a little searched the theory of a correspondence and searched word determine respectively the to sample sign bit of the fixed step size of searching a correspondence.
Further, the theory of each sampling being searched a correspondence searches that maximal value is defined as described fixed step size in the absolute value of first order difference, second order difference or third order difference of word.
So compared with prior art, in the technical scheme that the present invention proposes, by adopting a kind of digital successive approximation approach to automatically lock the different words of searching a little of searching, thereby reduce the word of searching of required storage to greatest extent, also improved simultaneously and searched precision.
Description of drawings
Fig. 1 is the functional-block diagram of the temperature frequency compensation/means for correcting among the present invention;
Fig. 2 is the functional-block diagram of an embodiment of the temperature and frequency correcting letter lock order unit among the present invention;
Fig. 3 is the process flow diagram of an embodiment of the temperature and frequency correcting word acquisition methods among the present invention;
Fig. 4 is reference frequency f
RThe temperature frequency performance diagram, wherein show the temperature frequency family curve after uncompensated temperature frequency family curve, temperature frequency compensated curve and the compensation;
Fig. 5 is the schematic flow sheet of another embodiment of the temperature and frequency correcting word acquisition methods among the present invention;
Fig. 6 is reference frequency f
RThe temperature frequency temperature frequency performance diagram of undergoing mutation;
Fig. 7 is the mensuration process flow diagram of an embodiment of the difference of the initial temperature frequency correction word among the present invention, initial temperature frequency correction word, fixed step size;
Fig. 8 is the calculation flow chart of an embodiment of the fixed step size symbol table among the present invention;
Fig. 9 is the block scheme of the embodiment who searches the word deriving means among the present invention.
Embodiment
Below in conjunction with Figure of description the specific embodiment of the present invention is described.Need to prove that at first the present invention is described in detail with the example that is applied as in temperature frequency compensation field for this paper, but the present invention is not limited to this kind physical application obviously.
An embodiment of the temperature frequency correcting apparatus that provides 100 among the present invention is provided Fig. 1.Described temperature frequency correcting apparatus 100 comprises frequency locking synthesis unit 110, frequency correction unit 130 and temperature and frequency correcting word generation unit 150.Described temperature and frequency correcting word generation unit 150 is used to generate corresponding temperature and frequency correcting word (the tempereturefrequency correction word of Current Temperatures T (also can be described as assigned temperature or target temperature) of input, be called for short TCW), this temperature and frequency correcting word TCW can be to the reference frequency f under the Current Temperatures T
RTemperature frequency drift compensate/proofread and correct.Described frequency correction unit 130 is used to utilize the temperature and frequency correcting word TCW of acquisition to frequency control word (frequency controlword, be called for short FCW) proofread and correct/compensate to obtain emending frequency control word (corrected frequencycontrol word is called for short FCW_new).Described frequency locking synthesis unit 110 is used for reference frequency f
RFor the basis generates the desired output frequency f according to emending frequency control word FCW_new
OUT
Wherein, the frequency control word FCW that imports among Fig. 1 can be the frequency control signal from the outside, described reference frequency f
RCan be the simulated clock simulation clock signal, it can the occurrence frequency drift with variation of temperature.Described Current Temperatures T can be a digital temperature value that is obtained by digital temperature sensor (not shown) induction Current Temperatures, the Current Temperatures T that certain digital temperature sensor provides can not need strictness to equal actual current temperature value, described Current Temperatures T also can be by a temperature of digital temperature sensor or miscellaneous equipment appointment or a target temperature of setting, therefore also can be referred to as relative temperature, target temperature or assigned temperature.It should be noted that in addition, described Current Temperatures T, temperature and frequency correcting word TCW, frequency control word FCW and emending frequency control word FCW_new are digital signals, (such as 32,16 or 8 the binary sequence) that they are normally represented by binary sequence.
In one embodiment, described frequency locking synthesis unit 110 generates the desired output frequency f according to following formula
OUT:
f
OUT＝K*FCW_new*f
R
Wherein K represents scale-up factor, the output frequency signal f that can obtain expecting according to scale-up factor K and emending frequency control signal FCW_new
OUT
In one embodiment, described frequency correction unit 130 generates emending frequency control word FCW_new according to following formula:
FCW_new＝FCW+TCW。
In one embodiment, such as the frequency signal of needs generation 890MHz, described frequency control word FCW can be the binary sequence of the described frequency values of expression, and described temperature and frequency correcting word TCW can be the described reference frequency f of expression
RThe binary sequence of the frequency drift corrected value under Current Temperatures, the frequency signal of the 890MHz that obtains by emending frequency control word FCW_new just can not produce bigger frequency drift with variation of temperature like this, that is to say that the output frequency of 890MHz has obtained temperature compensation.In another embodiment, described frequency control word FCW can change within the specific limits, and frequency control word FCW also can be used as frequency modulated signal to generate modulation output frequency f like this
OUTSuch as, needs generate frequency modulation (PFM) (Frequency Modulated) signal of 890MHz～910MHz frequency range, and described frequency control word FCW can be the binary sequence of the described frequency range of expression.
Fig. 4 shows reference frequency f
RUncompensated temperature frequency family curve, temperature frequency compensated curve and the temperature frequency family curve after the compensation, wherein said uncompensated reference frequency has in-50 ℃ to 125 ℃ temperature ranges approximately ± frequency drift of 10ppm, and the frequency drift that the frequency drift of the output after the compensation does not more compensate output reduces greatly.As shown in Figure 4, drift compensates to temperature frequency if arbitrary temperature value (or temperature spot), just can utilize this frequency correction value all to the correspondent frequency corrected value should be arranged.Here the frequency correction value of mentioning is exactly described temperature and frequency correcting word TCW.
Please consult shown in Figure 1ly once more, described temperature and frequency correcting word generation unit 150 (also can be referred to as temperature and frequency correcting word deriving means) also includes temperature comparing unit 152, temperature approaches unit 158, temperature and frequency correcting letter lock order unit 154 and primary data storage unit 156.
Described data storage cell 156 stores the initial temperature frequency correction word TCW (T0) of initial temperature point T0 correspondence, described temperature comparing unit 152 comparison object temperature T and current accounting temperature point Tx; At comparative result is that current accounting temperature point Tx is not when being in the lock-in range of target temperature T, described temperature and frequency correcting letter lock order unit 154 utilize the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence calculate convergence target temperature T next accounting temperature point (such as: if T Tx, then next accounting temperature point is Tx+S; If T＜Tx, then next accounting temperature point is Tx-S, described S is the predetermined temperature interval) corresponding temperature and frequency correcting word, described temperature approaches unit 158 is exported to temperature comparing unit 152 with next accounting temperature point of convergence target temperature as current accounting temperature point Tx and is proceeded comparison; At comparative result is current accounting temperature point Tx when being in the lock-in range of target temperature T, and described temperature and frequency correcting letter lock order unit 154 obtains the temperature and frequency correcting word TCW (T) of target temperature T correspondence according to the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence.The initial value of described current accounting temperature point Tx is initial temperature T0, and the first duration of the temperature and frequency correcting word of current accounting temperature point Tx correspondence is initial temperature frequency correction word TCW (T0).
Like this, do not need in the present invention all to store corresponding temperature and frequency correcting word for each temperature spot, the temperature and frequency correcting word that only needs storing initial adopts the successive approximation computing just can calculate the temperature and frequency correcting word TCW (T) of target temperature T correspondence afterwards.
In a concrete example, the lock-in range of described target temperature T can be in the predetermined temperature range that comprises Current Temperatures T.In addition, the lock-in range that described accounting temperature Tx is not in Current Temperatures T also bag can comprise two kinds of situations, and promptly described accounting temperature Tx is not in the lock-in range of Current Temperatures T and T and is not in the lock-in range of Current Temperatures T and T less than Tx greater than Tx and described accounting temperature Tx.For instance, T〉Tx+S can represent that described accounting temperature Tx is not in lock-in range and T greater than Tx, T＜Tx can represent that described accounting temperature Tx is not in lock-in range and T less than Tx, and Tx ≦ T＜Tx+S can represent that described accounting temperature Tx is in lock-in range.Again for instance, T〉Tx+S can represent that described accounting temperature Tx is not in lock-in range and T greater than Tx, T＜Tx-S can represent that described accounting temperature Tx is not in lock-in range and T less than Tx, and Tx-S＜T＜Tx+S can represent that described accounting temperature Tx is in lock-in range.
In a concrete enforcement, described primary data storage unit 156 also stores fixed step size and fixed step size symbol table, described fixed step size and described fixed step size symbol table can be the digital signals of being represented by binary sequence, store sign bit (the sign bit of the fixed step size of each discrete temperature spot correspondence in the described fixed step size symbol table, be called for short SB), just can represent that such as 10 can represent to bear.Described discrete temperature spot is meant to have the predetermined temperature temperature spot of S at interval, the described predetermined temperature size of S at interval can be chosen as required and can different values be set at different Applicable temperature scopes, such as S can be 0.2 ℃ a temperature range, is 0.1 ℃ in another temperature range.This predetermined temperature interval S has reflected the temperature covering precision of fixed step size symbol table, has just reflected the temperature covering precision in the temperature frequency compensation among the present invention.Give fixed step size with the symbol of each sign bit in the described fixed step size symbol table and just can obtain actual step size: SB (Tx)
*Fixed step size, wherein SB (Tx) can represent the sign bit of the fixed step size symbol table of temperature spot Tx correspondence.Wherein initial temperature frequency correction word TCW (T0), fixed step size and fixed step size symbol table can be interior by the primary data storage unit 156 of data signal line DATA input.
In a concrete example, at comparative result is current accounting temperature point Tx when not being in lock-in range and T greater than Tx, and described temperature and frequency correcting letter lock order unit 154 obtains the sign bit that current accounting temperature point Tx approaches the needed fixed step size of next accounting temperature point Tx+S (such as being sign bit in the fixed step size symbol table of current accounting temperature point Tx correspondence) from the fixed step size symbol table, give fixed step size with the sign bit that obtains and approach the needed actual step size of next accounting temperature point Tx+S to obtain current accounting temperature point Tx, utilize the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence and the temperature and frequency correcting word TCW (Tx+S) that actual step size obtains next accounting temperature point Tx+S correspondence.At comparative result is that accounting temperature Tx is not when being in lock-in range and T less than Tx, described temperature and frequency correcting letter lock order unit 154 obtains the sign bit that current accounting temperature point Tx approaches the needed fixed step size of next accounting temperature point Tx-S (because Tx-S＜Tx can claim that also Tx-S is last accounting temperature point) (such as being sign bit in the fixed step size symbol table of next accounting temperature point Tx-S correspondence) from the fixed step size symbol table, give fixed step size with the sign bit that obtains and approach the needed actual step size of next accounting temperature point Tx-S to obtain current accounting temperature point Tx, utilize the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence and the temperature and frequency correcting word TCW (Tx-S) that actual step size obtains next accounting temperature point Tx-S correspondence.
As can be seen in an example of the present invention, for a discrete temperature spot, described fixed step size symbol table only need be stored the sign bit of 1 bit binary data as the fixed step size of this temperature spot correspondence, thereby makes the data volume of described fixed step size symbol table become very little.Simultaneously, also can in the fixed step size symbol table, store the sign bit of more temperature spots, promptly can decrement keep predetermined temperature interval S smaller, can improve the precision of temperature frequency compensation like this.In the present invention by adopting a kind of digital desired temperature and frequency correcting value of frequency drift that interpolation method automatically locks different temperature spots of approaching one by one, thereby reduce the temperature and frequency correcting value of required storage to greatest extent, also improved simultaneously the precision of temperature frequency compensation, and determine that by digitized control able to programme reference clock source (as quartz crystal or other oscillator) at different performance or electronic system require the minimal hardware compensation scheme of required employing to frequency stability, have also reduced the cost and the performance requirement in system reference clock source in addition to greatest extent.
Fig. 2 is the functional-block diagram of an embodiment of the temperature and frequency correcting letter lock order unit 154 among Fig. 1.Described temperature and frequency correcting letter lock order unit 154 comprises that forward direction approaches computing unit 202, back to approaching computing unit 204, temperature and frequency correcting element word storage 206 and interpolation calculation unit 208.At comparative result is that accounting temperature Tx is not when being in lock-in range and T greater than Tx, described forward direction approaches computing unit 202 and obtain the sign bit that current accounting temperature point Tx approaches the needed fixed step size of next accounting temperature point Tx+S (such as being sign bit in the fixed step size symbol table of current accounting temperature point Tx correspondence) from the fixed step size symbol table, give fixed step size with the sign bit that obtains and approach the needed actual step size of next accounting temperature point Tx+S to obtain current accounting temperature point Tx, utilize the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence and the temperature and frequency correcting word TCW (Tx+S) that actual step size obtains next accounting temperature point Tx+S correspondence, and described temperature and frequency correcting word TCW (Tx+S) is stored into the temperature and frequency correcting word TCW (Tx) of accounting temperature frequency correction element word storage 206 to calculate as next time.At comparative result is that accounting temperature Tx is not when being in lock-in range and T less than Tx, described back obtains the sign bit that current accounting temperature point Tx approaches the needed fixed step size of a last accounting temperature point Tx-S (such as being sign bit in the fixed step size symbol table of next accounting temperature point Tx-S correspondence) to approaching computing unit 204 from the fixed step size symbol table, give fixed step size with the sign bit that obtains and approach the needed actual step size of next accounting temperature point Tx-S to obtain current accounting temperature point Tx, utilize the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx correspondence and the temperature and frequency correcting word TCW (Tx-S) that actual step size obtains next accounting temperature point Tx-S correspondence, and described temperature and frequency correcting word TCW (Tx-S) is stored into the temperature and frequency correcting word TCW (Tx) of accounting temperature frequency correction element word storage 206 to calculate as next time.When comparative result is in lock-in range for accounting temperature Tx, described interpolation calculation unit 208 utilizes temperature and frequency correcting word TCW (Tx) interpolation of storage to go out the pairing temperature and frequency correcting word of Current Temperatures T TCW (T), and exports it to frequency correction unit 130.
Fig. 3 shows the process flow diagram of an embodiment of the temperature and frequency correcting word acquisition methods among the present invention, and it has also reflected the course of work of described temperature and frequency correcting word generation unit 150.
Tx represents current accounting temperature point, and its initial value is initial temperature T0; The temperature and frequency correcting word of the current accounting temperature point Tx correspondence of TCW (Tx) expression, its initial value is initial temperature frequency correction word TCW (T0).
The value of described sign bit or be 1, or be 0, represent positive and negative respectively.
Step 315 utilizes the temperature and frequency correcting word TCW (Tx) of current accounting temperature point Tx and the actual step size of a last temperature spot Tx-S correspondence to ask for the corresponding temperature and frequency correcting word TCW (Tx-S) of an accounting temperature point.
Need explain, if the temperature sense precision of described digital temperature sensor (precision of Current Temperatures T) is than the temperature covering precision of described fixed step size symbol table, temperature sense precision such as described digital temperature sensor is 0.1 ℃, and the covering temperature accuracy of described fixed step size symbol table is 0.2 ℃ (being that S equals 0.2 ℃), will occur that accounting temperature Tx is in the lock-in range of Current Temperatures T and the situation that is not equal to Current Temperatures T needs just can obtain TCW (T) through interpolation.Yet, if the temperature sense precision of described digital temperature sensor is smaller or equal to the temperature covering precision of described fixed step size symbol table, accounting temperature Tx is in lock-in range and just is meant Tx=T so, like this after accounting temperature Tx is in lock-in range, described temperature and frequency correcting word TCW (Tx) is exactly the temperature and frequency correcting word TCW of Current Temperatures T correspondence, has therefore carried out interpolation arithmetic with regard to not needing.In addition, when the needs interpolation just can be obtained TCW (T), can adopt various interpolation methods, such as linear interpolation, non-linear interpolation, parabola interpolation etc., interpolation also may need near temperature and frequency correcting word such as TCW (Tx-S), TCW (Tx+S) in general except needs temperature and frequency correcting word TCW (Tx).
Calculate the temperature and frequency correcting word TCW of gained in output after,, enter step 321 afterwards with Tlock=T.
Step 321 reads digital temperature value T.
Step 323 judges whether described digital temperature value T equals described Tlock, if, then return step 321 and continue to read digital temperature value, otherwise return step 305, continue to repeat above-mentioned locking process.
By carrying out above-mentioned steps, the temperature and frequency correcting word that calculates Current Temperatures T correspondence that described temperature and frequency correcting word generation unit 150 utilizes TCW (T0), fixed step size and fixed step size symbol table to approach one by one quickly and accurately.Temperature and frequency correcting word for each temperature spot calculates, and only needs storage 1 bit sign data among the present invention, and this has significantly reduced memory data output.In addition, owing to only need store 1 bit data for each temperature spot, so the data that can store more temperature spots, the precision of frequency-temperature compensation has also increased greatly like this.
In a specific embodiment, in the described primary data storage unit 156 among Fig. 1 except storing initial temperature frequency correction word TCW (T0), fixed step size and fixed step size symbol table, also store the difference TCWd (T0) of initial temperature frequency correction word TCW (T0), the difference TCWd of wherein said temperature and frequency correcting word is meant the difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, fixed step size is then represented the absolute difference of difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, this moment, it can be represented with TCWds, also can be referred to as the difference fixed step size this moment in addition.Described initial temperature point T0 can for the minimum of temperature coverage (such as-30 ℃ to 50 ℃) such as-30 ℃.Store the sign bit SB of the fixed step size of each discrete temperature spot correspondence in the described fixed step size symbol table, the figure place of the binary sequence of described fixed step size symbol table depends on its temperature coverage and predetermined temperature S at interval, such as the temperature coverage is from-30 to 50 ℃, S is 0.2 ℃, the binary sequence that then needs (50-(30))/0.2-1=400-1 position is not (because maximum temperature point has next temperature spot for 50 ℃, therefore do not need to store the symbol of the corresponding fixed step size of this maximum temperature point, therefore can lack 1 bit data).It should be noted that TCW (T0), TCWd (T0), TCWds and fixed step size symbol table are interior by the data-carrier store 156 of data line importing, as for how determining these data will be described in more detail below.
Fig. 5 is the schematic flow sheet according to the temperature and frequency correcting word acquisition methods of above-mentioned specific embodiment.
See also shown in Figure 5ly, the computing method of temperature and frequency correcting word TCW comprise the steps.
Step 501, initialization Tx, TCW (Tx), TCWd (Tx).
Tx represents current accounting temperature point, the temperature and frequency correcting word of TCW (Tx) expression accounting temperature point Tx correspondence, the difference of the temperature and frequency correcting word of TCWd (Tx) expression accounting temperature point Tx correspondence.Described initialization can be in addition:
Tx＝T0；TCW(Tx)＝TCW(T0)；TCWd(Tx)＝TCWd(T0)。
Step 503 reads digital temperature value T, is exactly that preamble is mentioned Current Temperatures or target temperature.
Step 505 judges that whether described digital temperature T value is more than or equal to Tx+S, if change step 507 over to; Otherwise change step 513 over to.
Step 507 reads the sign bit SB (Tx) in the fixed step size symbol table of current accounting temperature point Tx correspondence, gives the actual step size that TCWds forms Current Temperatures point Tx correspondence with this symbol: SB (Tx) * TCWds.This sign bit or be 1, or be 0, wherein 1 expression just, 0 expression is negative.
Step 509 is asked for the difference TCWd (Tx+S) of the temperature and frequency correcting word of the temperature and frequency correcting word TCW (Tx+S) of next accounting temperature point Tx+S correspondence and next accounting temperature point Tx+S correspondence.
TCW (Tx+S)=TCW (Tx)+TCWd (Tx) wherein;
TCWd(Tx+S)＝TCWd(Tx)+SB(Tx)＊TCWds；
This process of asking for the correlation of next accounting temperature point can be called as forward direction and proofread and correct.
Step 511, Tx=Tx+S in addition, and return step 503.Here why will turn back to 503, and not turn back to 505, be because described digital temperature T may change in computation process.
Step 513 continues to judge that whether described digital temperature T is less than Tx.If then change step 515 over to; Otherwise, change step 521 over to.
Step 515 reads the sign bit SB (Tx-S) in the fixed step size symbol table of an accounting temperature point Tx-S correspondence, gives the actual step size that TCWds forms a last accounting temperature point Tx-S correspondence: SB (Tx-S) * TCWds with this symbol.
Step 517, the difference TCWd (Tx-S) that asks for the temperature and frequency correcting word of an accounting temperature point Tx-S correspondence reaches the temperature and frequency correcting word TCW (Tx-S) of a last accounting temperature point Tx-S correspondence.
TCWd (Tx-S)=TCWd (Tx)-SB (Tx-S) * TCWds wherein
TCW(Tx-S)＝TCW(Tx)-TCWd(Tx-S)，
Proofread and correct with respect to foregoing forward direction, the correlation of asking for an accounting temperature point here gets process and can be called as the back to correction.
Step 519, Tx=Tx-S in addition, and return step 503.Equally, why will turn back to 503 here, and not turn back to 505, be because described digital temperature T may change in computation process.
Step 521, if this moment, current accounting temperature point Tx equaled described digital temperature T, the TCW (Tx) that then will calculate gained is as the temperature and frequency correcting word TCW output of calculating gained; If Tx+S〉T〉Tx, then utilize TCW (Tx) and TCW (Tx+S) interpolation to obtain TCW (T) and its temperature and frequency correcting word TCW output as the calculating gained.
Calculate the temperature and frequency correcting word TCW of gained in output after,, enter step 523 afterwards with Tlock=T.
Step 523 reads digital temperature value T.
Step 525 judges whether described digital temperature value T equals described Tlock, if, then return step 523 and continue to read digital temperature value, otherwise return step 505, continue to repeat above-mentioned locking process.
For instance, when described initial temperature T0 is temperature coverage minimum-30 ℃, when each temperature frequency compensation system 100 shown in Figure 1 comes into operation, described digital temperature sensor can provide Current Temperatures T, such as T is 20 ℃, so flow process can continuous repeating step 503-511 to allow the Tx value approach 20 ℃ from-30 ℃ fast, enter step 513 afterwards until last locking temperature T.During the unexpected change of temperature in use, such as unexpected decline, flow process can reenter the tracking locking process, and promptly repeating step 503,505,513-519 step enter step 521 with locking temperature T afterwards to allow Tx approach new T value fast at once.
As seen characteristics of the acquisition methods of the temperature and frequency correcting word among the present invention, advantage is: utilize initial temperature frequency correction word, the difference of initial temperature frequency correction word starts trace flow, constantly utilize the corresponding temperature and frequency correcting word of current accounting temperature point, the difference of temperature and frequency correcting word, sign bit in the fixed step size symbol table and fixed step size calculate the temperature and frequency correcting word of correspondence of next accounting temperature point of convergence target temperature, be locked to Current Temperatures point T until the accounting temperature point, carry out trying to achieve the temperature and frequency correcting word of Current Temperatures point T correspondence according to interpolation.
As shown in Figure 6, the temperature frequency characteristic curve of reference frequency can be undergone mutation under a certain section temperature, and this is a kind of very common phenomena.If it is bigger that the interval of Tc point is provided with, the frequency compensation of the temperature province of undergoing mutation for frequency will out of true, and this also is a very big defective in the existing temperature frequency compensation technique.Utilize the technical scheme of obtaining of aforesaid temperature and frequency correcting word among the present invention, can effectively store abundant temperature spot data (a bit sign bit data), thereby the situation of this frequency discontinuity shown in Figure 6 be realized the temperature frequency compensation of very good effect.
Below, introduce the mensuration process of TCW (T0), TCWd (T0), TCWds and fixed step size symbol table in detail once.Wherein, Fig. 7 shows the TCW (T0) among the present invention, the mensuration process of TCWd (T0), TCWds, and Fig. 8 shows the acquisition process of the fixed step size symbol table among the present invention.
As shown in Figure 7, the assay method of described TCW (T0), TCWd (T0), TCWds comprises the steps.
Step 701 obtains reference frequency f
RThe temperature frequency curve.
The whole bag of tricks acquisition of the prior art can be passed through, but the temperature frequency curve and the actual reference frequency f of its generation must be will guaranteed
RThe temperature frequency curve consistent as far as possible, and keep the level and smooth of curve.In one embodiment, when the temperature frequency sudden change that does not have as shown in Figure 6, can adopt Beckman curve maker (Bechamann curve generator), by using a few temperature frequency test point just can generate more accurate temperature frequency family curve, repeat no more here.
Step 703 is that temperature sampling is sampled to obtain each discrete Tc point frequency value corresponding to described temperature frequency curve at interval with S, and the value of described S will determine the temperature covering precision of described fixed step size symbol table.In an example, described S value can be set different values at different temperature applicable ranges, uses 0.1 ℃ as temperature sampling S at interval such as 0 ℃ in Fig. 6-20 ℃, and other temperature ranges in Fig. 6 are used 0.2 ℃ as temperature sampling S at interval.
Step 705 according to the frequency values of each Tc point and the funtcional relationship between the temperature and frequency correcting word, utilizes each Tc point frequency value corresponding to ask for the theoretical temperatures frequency correction word TCW of each Tc point Tx correspondence
Ideal(Tx), wherein Tx represents to be spaced apart the discrete Tc point from min (Tx) to max (Tx) of S, and min (Tx) is the minimum value of Tx, and max (Tx) is the maximal value of Tx.
The theoretical temperatures frequency correction word TCW of each Tc point Tx correspondence
Ideal(Tx) will go on record and be used for determining the value of described each sign bit of fixed step size symbol table.
Step 707 is calculated the theoretical temperatures frequency correction word TCW of each Tc point Tx correspondence
Ideal(Tx) difference TCWd
Ideal(Tx), wherein
TCWd
ideal(Tx)＝TCWd
ideal(Tx+S)-TCWd
ideal(Tx)，
Tx belongs to [min (Tx), max (Tx-S)] herein.
Step 711 is calculated the theoretical temperatures frequency correction word TCW of each Tc point Tx correspondence
Ideal(Tx) difference TCWd
Ideal(Tx) difference TCWdd
Ideal(Tx), i.e. theoretical temperatures frequency correction word TCW
Ideal(Tx) second order difference, wherein
TCWdd
ideal(Tx)＝TCWd
ideal(Tx+S)-TCWd
ideal(Tx)，
Tx belongs to [min (Tx), max (Tx-2S)] herein.
Step 713 is with the theoretical temperatures frequency correction word TCW of each Tc point Tx correspondence
Ideal(Tx) second order difference TCWdd
Ideal(Tx) the absolute value maximum is recorded as previously described difference fixed step size TCWds in.Why choosing maximal value is in order to guarantee that matched curve (curve that promptly utilizes each accounting temperature frequency correction word that the difference fixed step size calculates to form) can catch up with the variation of ideal curve (being the temperature frequency curve that obtains in the step 701) for difference step size TCWds.Certainly in other embodiments, also can choose slightly little second order difference value is the difference fixed step size.
Hence one can see that, needing in the described primary data storage unit just can obtain the initial temperature frequency correction word TCW (T0) that preserves, the difference TCWd (T0) and the difference step size TCWds of initial temperature frequency correction word through execution in step 701-713.
Subsequently, can utilize the initial temperature frequency correction word TCW (T0) that has obtained, difference TCWd (T0), difference step size TCWds and the corresponding theoretical temperatures frequency correction word TCW of described each Tc point of initial temperature frequency correction word
Ideal(Tx) value of bits per inch certificate in the described fixed step size symbol table of acquisition.Please referring to shown in Figure 8, the acquisition process of the value of each bit data is as follows in the described fixed step size symbol table.
Tx represents current Tc point, the temperature and frequency correcting word of NTCW (Tx-S) expression Tx-S temperature spot correspondence, the difference of the temperature and frequency correcting word of the temperature and frequency correcting word correspondence of NTCWd (Tx-S) expression Tx-S temperature spot correspondence.It should be noted that, the temperature and frequency correcting word NTCW (Tx-S) of Tx-S temperature spot correspondence is not described theoretical temperatures frequency correction word, but the temperature and frequency correcting word that comes out according to the Difference Calculation of initial temperature frequency correction word and initial temperature frequency correction word.
Suppose that at previously described initial temperature T0 be the minimum that practical application covers temperature range, so described initialization is exactly:
Tx＝T0+S；NTCW(Tx-S)＝TCW(T0)；NTCWd(Tx-S)＝TCWd(T0)。
Here because initial temperature T0 is the minimum temperature value, the temperature spot Tx that therefore need ask for only need equal the value of the corresponding positions in the fixed step size symbol table that T0+S just can realize asking for each temperature spot correspondence.If initial temperature T0 is a mxm., then need other Tx=T0-S, other parameter also needs according to the same rule corresponding modify.
NTCW(Tx)＝NTCW(Tx-S)+NTCWd(Tx-S)。
Step 805 supposes that the value of sign bit SB (Tx-S) in the fixed step size symbol table of Tx-S temperature spot correspondence is 0, asks for the first accounting temperature frequency correction word NTCW0 (Tx+S) of Tx+S temperature spot correspondence, is specially:
NTCW0(Tx+S)＝NTCW(Tx)+NTCWd(Tx)
＝NTCW(Tx-S)+NTCWd(Tx-S)+NTCWd(Tx-S)+SB(Tx)＊TCWds
＝NTCW(Tx-S)+2＊NTCWd(Tx-S)-TCWds。
DNTCW0(Tx+S)＝Abs(TCW
ideal(Tx+S)-NTCW0(Tx+S))。
Step 809 supposes that the value of sign bit SB (Tx-S) in the fixed step size symbol table of Tx-S temperature spot correspondence is 1, asks for the second accounting temperature frequency correction word NTCW1 (Tx+S) of Tx+S temperature spot correspondence, is specially:
NTCW1(Tx+S)＝NTCW(Tx-S)+2＊NTCWd(Tx-S)+SB(Tx-S)＊TCWds
＝NTCW(Tx-S)+2＊NTCWd(Tx-S)+TCWds。
DNTCW1(Tx+S)＝Abs(TCW
ideal(Tx+S)-NTCW0(Tx+S))。
DNTCW0 (Tx+S)＜DNTCW1 (Tx+S) if then enter step 815, otherwise enters step 817.
NTCWd(Tx)＝NTCWd(Tx-S)-TCWds。
NTCWd(Tx)＝NTCWd(Tx-S)+TCWds。
Step 825 judges that Tx whether smaller or equal to MAX (Tx)-S, if not, then finishes calculation process, otherwise returns step 803, repeats above-mentioned steps.
Carry out above-mentioned steps 801-825, just can calculate the value of each data in the described fixed step size symbol table.
Difference TCWd (T0), difference step size TCWds and the fixed step size symbol table of the last initial temperature frequency correction word TCW (T0) that just mensuration can be come out, initial temperature frequency correction word import data storage cell 156 by data line.
In another specific embodiment, in the described data storage cell 156 except storing initial temperature frequency correction word TCW (T0), fixed step size and fixed step size symbol table, also store the difference TCWd (T0) of initial temperature frequency correction word TCW (T0), the second order difference TCWdd (T0) of initial temperature frequency correction word TCW (T0), the difference TCWd of wherein said temperature and frequency correcting word is meant the difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, the second order difference TCWdd of described temperature and frequency correcting word is meant the difference of difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, fixed step size is then represented the difference of second order difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, this moment, it can be represented with TCWdds, and also can be referred to as the second order difference fixed step size this moment.In this embodiment, the computation process of obtaining of temperature and frequency correcting word TCW can mainly be that step 509 and 517 is understood some variation with reference to computation process shown in Figure 5, and wherein step 509 becomes:
TCW(Tx+S)＝TCW(Tx)+TCWd(Tx)
TCWd(Tx+S)＝TCWd(Tx)+TCWdd(Tx)
TCWdd(Tx+S)＝TCWdd(Tx)+SB(Tx)＊TCWdds，
Wherein step 517 becomes:
TCWdd(Tx-S)＝TCWdd(Tx)-SB(Tx-S)＊TCWdds
TCWd(Tx-S)＝TCWd(Tx)-TCWdd(Tx-S)
TCW(Tx-S)＝TCW(Tx)-TCWd(Tx-S)
Similarly, some variations also can take place in the difference TCWd (T0) of initial temperature frequency correction word TCW (T0), initial temperature frequency correction word TCW (T0), second order difference TCWdd (T0), the second order difference fixed step size TCWdds of initial temperature frequency correction word TCW (T0) and the mensuration process of fixed step size symbol table, but principle is identical with previous examples, just repeats no more here.Certainly, other are executed and also may use the above difference in three rank or three rank in the example, and principle is all similar, holds and does not give unnecessary details.
In another specific embodiment, only store initial temperature frequency correction word TCW (T0), fixed step size and fixed step size symbol table in the described data storage cell 152, described fixed step size table is then represented the difference of the temperature and frequency correcting word of adjacent temperature spot correspondence, and this moment, it can be represented with TCWs.In this embodiment, the computation process of temperature and frequency correcting word TCW can mainly be that step 509 and 517 is understood some variation with reference to computation process shown in Figure 5, and wherein step 509 becomes:
TCW(Tx+S)＝TCW(Tx)+SB(Tx)＊TCWs
Wherein step 517 becomes:
TCW(Tx-S)＝TCW(Tx)-SB(Tx-S)＊TCWs。
Similarly, some variations also can take place in the mensuration process of initial temperature frequency correction word TCW (T0), fixed step size TCWs and fixed step size symbol table, but principle is identical with previous examples, just repeats no more here.
As shown in Figure 6, the temperature frequency family curve of reference frequency can be undergone mutation in a certain specified temp zone frequency, in order to take into account this situation of frequency discontinuity, the present invention need consider this special circumstances in selected fixed step size, this just may cause when the accounting temperature frequency correction word of normal temperature zone, is not very accurate.In order to address the above problem, in a preferred embodiment, can not only store one group of primary data in the described data storage cell 156, can also store two groups or three groups of primary datas.Every group of primary data can comprise the difference of initial temperature correct word, initial temperature correct word and the value of three parameters of difference fixed step size, the value that also can comprise initial temperature correct word and two parameters of fixed step size can also comprise the difference of initial temperature correct word, initial temperature correct word, the second order difference of initial temperature correct word and the value of four parameters of second order difference fixed step size.Every group of primary data all has corresponding temperature range separately, and only is suitable in the temperature range of being responsible for separately.For instance, can store three groups of initial temperature frequency correction words, the difference of initial temperature frequency correction word, difference fixed step size for the temperature frequency characteristic curve among Fig. 6, first group initial temperature point is-30 ℃, second group initial temperature point is 0 ℃, the 3rd group initial temperature point is 20 ℃, first group of primary data is used for the temperature and frequency correcting between-30 ℃-0 ℃, second group of primary data is used for the temperature and frequency correcting between 0 ℃-20 ℃, and the 3rd group of primary data is used for the temperature and frequency correcting between 20 ℃-100 ℃.Certainly, the value of each bit data in the fixed step size symbol table also is to rely on the primary data in the temperature range separately to try to achieve, and therefore also can only be used in the temperature range separately.Like this, can set up the primary data of oneself, make the tracking correction effect among the present invention better accurately at temperature frequency sudden change zone.
In sum, characteristics of the scheme of obtaining of temperature and frequency correcting word of the present invention, advantage or progressive being: be not the temperature and frequency correcting word (such as 32 bit data) of as of the prior art, storing each temperature spot correspondence, but only store symbol (1 bit data) and one or a few fixed step size and the initial temperature frequency correction word of the fixed step size of each temperature spot correspondence, when needs obtain the temperature and frequency correcting word of Current Temperatures correspondence, sign bit according to the fixed step size of each temperature spot correspondence, the temperature and frequency correcting word of fixed step size and last computation (initial value is an initial temperature frequency correction word) calculates one by one and levels off to the temperature and frequency correcting word of Current Temperatures, is locked in the temperature and frequency correcting word of Current Temperatures until result of calculation.
In principle, correct word of the present invention is obtained scheme and is not limited to obtaining of temperature and frequency correcting word, and its look-up table (look-up table) that utilizes that can be used to replace in existing any technical field obtains the scheme of the target value of searching.Specifically, the present invention also proposes a kind of value of searching (also can be referred to as to search word) deriving means and method, and it is used to obtain the current value of the searching V that searches a P correspondence.As shown in Figure 9, the described value of searching deriving means 950 is with respect to described temperature and frequency correcting word generation unit 150, and it also includes and search a comparing unit, searches an approximation unit, the value of searching lock cell and primary data storage unit.Wherein, a current P that searches calculates and searches Px correspondence accounting temperature point Tx above, the value of searching V correspondence temperature and frequency correcting word TCW above corresponding to above Current Temperatures point T.
The described value of searching obtain scheme and above temperature and frequency correcting word to obtain scheme the same, only need will temperature spot T above replace with and search a P, accounting temperature point Tx and replace with calculating and search a Px, temperature and frequency correcting word TCW and replace with the value of searching V, just the value of searching that can obtain among the present invention is obtained scheme.Illustrate substitute mode below, can replace with reference to substitute mode hereinafter as for unaccounted part.
In one embodiment, described primary data storage unit can be searched the initially value of searching V (P0) of a P0 correspondence, difference Vd (P0), fixed step size and the fixed step size symbol table of the described initially value of searching V (P0) by storing initial, the difference Vd of the described value of searching is meant adjacent difference of searching value of searching of correspondence, fixed step size then represent adjacent search a correspondence the difference of difference, this moment, it can be represented with Vds, and also can be referred to as the difference fixed step size this moment.Store each discrete sign bit SB that searches the fixed step size of a correspondence in the described fixed step size symbol table.
In this embodiment, step 507 as shown in Figure 5 reads the sign bit SB (Px) in the fixed step size symbol table that current calculating searches a Px correspondence, gives Vds with this symbol and forms the current actual step size of Px correspondence: SB (Px) * Vds that searches.
Step 509 as shown in Figure 5, ask for next calculating and search the value of the searching V (Px+S) of a Px+S correspondence and next calculating and search a difference Vd of the value of searching of Px+S correspondence (Px+S) and be:
V(Px+S)＝V(Px)+Vd(Px)；
Vd(Px+S)＝Vd(Tx)+SB(Px)＊Vds；
Wherein Px represents that current calculating searches a little, Px+S represents that next calculating that the convergence target is searched a little searches a little, value of searching of Px correspondence is searched in the current calculating of V (Px) expression, V (Px+S) represents that next calculating searches value of searching of correspondence, wherein S represents the adjacent predetermined space of searching a little, a difference of the value of searching of Px correspondence is searched in the current calculating of Vd (Px) expression, Vd (Px+S) represents that next calculating searches a difference of the value of searching of Px+S correspondence, Vds represents fixed step size, and SB (Px) searches sign bit in the fixed step size symbol table of a Px correspondence for current calculating.
In addition in this embodiment, step 515 as shown in Figure 5, read the sign bit SB (Px-S) in the fixed step size symbol table that a calculating searches a Px-S correspondence, give Vds with this symbol and form a last calculating and search the actual step size of Px-S correspondence: SB (Px-S) * Vds.
Step 517 as shown in Figure 5, ask for one and calculate the value of the searching V (Px-S) search a Px-S correspondence and a last calculating and search a difference Vd of the value of searching of Px-S correspondence (Px-S) and be:
Vd(Px-S)＝Vd(Tx)-SB(Px-S)＊Vds；
V(Px-S)＝V(Px)+Vd(Px)。
Those of ordinary skill is after having checked above-mentioned replacement, and nature can expect that remainder may replace according to similar principle, has therefore just repeated no more here.The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement etc., all should be included within protection scope of the present invention.
Claims (10)
1. search the word deriving means for one kind, be used to find the current word of searching of searching a correspondence, it is characterized in that it comprises:
Data storage cell, be used to store ideal is searched curve with the predetermined primary data of carrying out sampling analysis at interval and obtaining of searching, described primary data comprises initially searches searching word, fixed step size and storing the fixed step size symbol table of some sign bits of fixed step size of a correspondence;
Search letter lock order unit, be used for according to described primary data and before interim result data obtain to calculate and search the word of searching of a correspondence, to such an extent as to described calculating is searched a little with corresponding and is searched the formed matched curve of word and can search curve along described ideal and approach described current searching a little one by one from initially searching to light, it a little is to be spaced apart step-length and constantly a little to approach until entering current the searching a little of a little predetermined lock-in range of searching to current searching one by one from initially searching to light with described predetermined searching that described calculating is searched, interim result data is searched the calculating of having obtained before when a little not entering current predetermined lock-in range of searching a little and is searched the word of searching of a correspondence for calculating before described, and searches in described calculating and to export the word of searching that a correspondence is searched in described calculating when a little entering described current predetermined lock-in range of searching a little.
2. the word deriving means of searching as claimed in claim 1 is characterized in that: search searching before the word of a correspondence in the described calculating of output, also need it is carried out interpolation processing to obtain the accurate current word of searching of searching a correspondence.
3. as the arbitrary described word deriving means of searching of claim 1-2, it is characterized in that: described according to described primary data and before interim result data obtain and calculate the word of searching of searching a correspondence and comprise:
Obtaining current calculating from the fixed step size symbol table searches and a little approaches next calculating and search the some sign bit of needed fixed step size, it a little is to search a little towards described current searching from current calculating a little to step nearly one and predeterminedly search calculating at interval and search a little that described next calculating is searched, and described current calculating is searched a little initial value for initially searching a little;
Giving fixed step size with the sign bit that obtains searches and a little approaches described next calculating and search a little needed actual step size to obtain current calculating;
Utilize current calculating search a correspondence search word and actual step size obtains the word of searching that a correspondence is searched in described next calculating;
Described next calculating searched a little search a little and repeat aforesaid operations as the new current calculating of lower whorl.
4. as the arbitrary described word deriving means of searching of claim 1-2, it is characterized in that:
The ideal temperature frequency characteristic is carried out sampling analysis at interval and comprises with predetermined searching:
A selected sampling is searched a little to initially searching a little, and the sampled value of searching a correspondence according to this sampling of selecting calculates the word of searching of initially searching a correspondence;
Search the value that a little sampled value calculates each sign bit in described fixed step size, the fixed step size symbol table according to each sampling.
5. search the word acquisition methods for one kind, be used to find the current word of searching of searching a correspondence, it is characterized in that it comprises:
At interval ideal is searched curve and carry out sampling analysis and obtain primary data with predetermined searching, described primary data comprise initially search a correspondence search word, fixed step size and fixed step size symbol table, described fixed step size symbol table records the sign bit that the fixed step size of a correspondence is searched in each sampling;
According to described primary data and before interim result data calculate from initially search light with predetermined search be spaced apart step-length constantly to current search a little to approach until being locked in current calculating of searching preset range a little search the word of searching of a correspondence, to such an extent as to described calculating is searched a little with corresponding and is searched the formed matched curve of word and can search curve along described ideal and approach described current searching a little one by one from initially searching to light, described before interim result data search the calculating that a non-locking obtained when the current preset range of searching a little and search the word of searching of a correspondence for calculating;
Search when a little being locked in the described current preset range of searching some the word interpolation of searching of searching a correspondence in described calculating and obtain the described current word of searching of searching a correspondence according to described calculating.
6. the word acquisition methods of searching as claimed in claim 5 is characterized in that: the described predetermined size at interval of searching is different with the difference of seek scope.
7. the word acquisition methods of searching as claimed in claim 5 is characterized in that: be different seek scope settings on the same group primary data not, every group of primary data is corresponding to the seek scope of each self application.
8. as the arbitrary described word acquisition methods of searching of claim 5-7, it is characterized in that:
Described according to described primary data and before interim result data calculate from initially search light with predetermined search be spaced apart step-length constantly to current search a little to approach until being locked in current calculating of searching preset range a little search the word of searching of a correspondence and comprise:
Obtaining current calculating from the fixed step size symbol table searches and a little approaches next calculating and search the some sign bit of needed fixed step size, it a little is to search a little towards described current searching from current calculating a little to step nearly one and predeterminedly search calculating at interval and search a little that described next calculating is searched, and the initial value that described current calculating is searched a little is an initial temperature;
Giving fixed step size with the sign bit that obtains searches and a little approaches described next calculating and search a little needed actual step size to obtain current calculating;
Utilize current calculating search a correspondence search word and actual step size obtains the word of searching that a correspondence is searched in described next calculating;
Described next calculating searched a little search a little and repeat aforesaid operations and search until current calculating and a little be locked in the current preset range of searching a little as the new current calculating of lower whorl.
9. as the arbitrary described word acquisition methods of searching of claim 5-7, it is characterized in that:
Describedly ideal is searched curve carry out sampling analysis at interval and comprise with predetermined searching:
The theory of utilizing each sampling of the sampling value of searching calculating to search is a little searched word;
A selected sampling is searched a little to initially searching a little, and to search word be exactly the word of searching of initially searching a correspondence to this sampling theory of searching a correspondence so;
The theory of searching a correspondence according to each sampling is searched first order difference, second order difference or the third order difference of word and is determined described fixed step size;
According to the fixed step size of determining, initially search word and each sampling of searching a little searched the theory of a correspondence and searched word determine respectively the to sample sign bit of the fixed step size of searching a correspondence.
10. the word acquisition methods of searching as claimed in claim 9,, it is characterized in that: the theory that a correspondence is searched in each sampling searches that maximal value is defined as described fixed step size in the absolute value of first order difference, second order difference or third order difference of word.
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