CN103995298B - Method for optimization selection of proton magnetometer matching capacitor - Google Patents
Method for optimization selection of proton magnetometer matching capacitor Download PDFInfo
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- CN103995298B CN103995298B CN201410250716.7A CN201410250716A CN103995298B CN 103995298 B CN103995298 B CN 103995298B CN 201410250716 A CN201410250716 A CN 201410250716A CN 103995298 B CN103995298 B CN 103995298B
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Abstract
The invention discloses a method for optimization selection of a proton magnetometer matching capacitor, and belongs to the technical field of magnetic field intensity detection. The method for optimization selection of the matching capacitor comprises the processes of determining matching circuit system parameters, determining the fixed minimum capacitance Cmin and gradually determining the matching capacitor. The method for optimization selection of the matching capacitor according to the matching circuit bandwidth is provided under the condition that certain frequency points are not located within the bandwidth of a matching circuit due to limited capacitor combination and matching, and the whole matching circuit bandwidth can cover the whole system bandwidth. Meanwhile, the matching method for the circuit with capacitance errors is obtained through analysis under the condition that the errors exist between actual capacitance and ideal capacitance, and the problem that due to matching frequency emission offset caused by the capacitor capacitance value errors, certain frequency points are not within the circuit bandwidth range is solved. According to the method, the matching capacitor can be selected according to different measuring ranges, and the precision of later measuring signals is improved.
Description
Technical field
The invention belongs to the technical field of magnetic field intensity detection is and in particular to a kind of rotary proton for weak magnetic measurement
The method that the optimum choice of magnetometer joins humorous electric capacity, it is possible to resolve some frequencies do not cause its signal quality joining in humorous circuit bandwidth
The problem being deteriorated.
Technical background
Proton-precession magnetometer does the principle of precessional motion in magnetic field using Hydrogen Proton and makes, for measuring earth's magnetic field
Overall strength (referring to bibliography J.A.Koehler, " Proton Precession Magnetometer ", Rev 2 Comox,
BC,Canada,November 2004.).It is a kind of higher magnetometer of precision, can perceive the faint change in earth's magnetic field.
Since the fifties in last century, proton-precession magnetometer has obtained fast development, is widely used in geologic prospect, earthquake prediction,
Day become monitoring etc. (build this referring to bibliography Liu. Proton Precession Magnetometer is in the development of China and application (summary) [J]. state
Border Behaviour of seismicity .1982 (3) .).
Proton-precession magnetometer is mainly made up of probe and main frame two parts.Probe segment has coil and solution (kerosene, first
Alcohol, water etc.), it is mainly used in the polarization of proton and the extraction of rotary proton signal；Host machine part is divided into polar system and reception
The excitation of system, predominantly rotary proton provides energy, and is nursed one's health (referring to bibliography to receiving the precession signal obtaining
W.D.S Ruhunusiri and M.K.Jayananda,“Construction of a Proton Magnetometer”,
Proceedings of the Technical Sessions,2008,24:78-85.).Involved joining in present patent application
Humorous circuit is in the reception system first order, and it mainly carries out frequency-selecting and amplification using LC parallel resonance characteristic to signal.LC is in parallel
The feature of frequency selection circuit is：On resonance center frequeH, signal can obtain higher gain, and outside resonance circuit bandwidth
Signal gain declines rapidly, if joined within humorous circuit bandwidth so signal can not be made just to fall, signal quality cannot
Ensure.
The earth's magnetic field scope that actual proton-precession magnetometer can measure typically can reach 20000～90000nT, root
Obtain according to lamer precession rule, the frequency range of proton free damping signal is 0.85～3.83kHz, so rotary proton magnetic
Power instrument all using multiple join humorous capacitor combination in the form of realize wideband join humorous.Chinese patent CN 1041222A is using joining humorous electric capacity
Many combining forms, a kind of accurate measurement joined humorous method from motion tracking, meet different needs is provided.However, despite multiple
Join the combination of humorous electric capacity, but these the limited capacitor's capacity joining humorous capacitor combination is simultaneously discontinuous, therefore occurs some
Frequency is not joining the situation within humorous circuit bandwidth.In this case, signal quality is deteriorated, and affects certainty of measurement；In addition, joining humorous
The capacitance error of electric capacity also can make to join humorous circuit bandwidth, centre frequency changes, thus leading to join humorous failure.But above-mentioned patent
Do not analyze and solve how all frequencies are joined humorous circuit bandwidth all standing and capacitance error leads to join the not true of humorous circuit
Determine problem, and the how specifically chosen capacitance joining humorous electric capacity.Therefore, propose a kind of optimization for this two problem present invention to select
Select the method joining humorous electric capacity, under conditions of considering to join humorous capacitor's capacity error, realization is joined humorous circuit bandwidth and can be covered entirely
Measurement frequency band, thus ensure the signal quality of measured signal.
Content of the invention
It is an object of the invention to provide a kind of method that optimum choice joins humorous electric capacity, can be with effectively solving due to capacitor's capacity
Error and cause some frequencies not joining in humorous circuit bandwidth, thus leading to the problem of degradation it is ensured that any measured signal
Quality, thus improving the certainty of measurement of proton magnetometer.
When joining humorous circuit using LC parallel connection, by a series of join humorous capacitor combination by way of obtain multiple capacitances, realize not
Joining of same frequency signal is humorous.Measurement range is divided into several frequency ranges by the corresponding resonant frequency of these capacitances, each frequency range
Size determined by its adjacent resonant frequencies.If corresponding to adjacent resonant frequencies bandwidth by the institute in its corresponding frequency band region
There is frequency all to cover, then will not reduce below -3dB from the minimum amplitude joining humorous circuit output signal.
First, all frequencies are converted into adjacent resonant frequencies and band by the problem joining humorous circuit bandwidth all standing by the present invention
Relation between width, according to the relation joining humorous circuit bandwidth and resonant frequency, and then is converted into the pass between adjacent resonant frequencies
System.Secondly, the present invention leads to the problem of resonance frequency shift for the actual capacitance error joining humorous electric capacity, by theoretical calculation and
Analysis, under the conditions of being given at certain error, restriction relation between two adjacent resonant frequencies, such that it is able to according to one of
Resonant frequency obtains another resonant frequency, and the value of humorous electric capacity is joined in final acquisition.
For solving the technical problem of the present invention, provide following technical scheme, the application conditions of the method are as shown in Figure 1
Join humorous circuit：
A kind of method that humorous electric capacity joined by optimum choice proton magnetometer, specifically joins humorous process as follows：1) determine and join humorous electricity
The systematic parameter on road, 2) determine fixing minimum capacity, 3) determine the frequency band all standing condition joining humorous circuit, 4) according to actual capacitance
Error, calculates the final resonant frequency mated and joins humorous electric capacity.
1) humorous Circuits System parameter is joined in the determination described in, refers to determine probe inductance L inductance value, internal resistance r resistance of popping one's head in, coupling
Resistance R resistance, capacitor's capacity error delta C/C, scope f of systematic survey frequencymin～fmax.
2) minimum capacity is fixed in the determination described in, is according to proton magnetometer range of dynamic measurement, by maximum measurement frequency
fmaxCorresponding capacitance is as fixing minimum capacity Cmin.This fixation minimum capacity is not required to switch control rule, be directly connected in join humorous
Circuit.Therefore fixing minimum capacity participates in capacitance combination all the time.For as shown in Figure 1 humorous circuit of joining, fixing minimum joins humorous electricity
Hold CminWith maximum resonance frequency fmaxRelation is as follows：
Cmin=1/ ((2 π fmax)2*L) (1)
3) humorous circuit frequency band all standing condition is joined in the determination described in, refers to the problem selecting to join humorous electric capacity is converted into complete
Restricted problem between adjacent resonant frequencies under coverage condition.The i.e. corresponding relation according to resonant frequency and bandwidth, from high resonance
Progressively recursion obtains adjacent low resonant frequency to frequency, and the relation joining humorous circuit bandwidth BW with resonant frequency f is：
BW=r/2 π L+2 π Lf2/R (2)
It is analyzed as follows further：
Initially set up model as shown in Figure 2, joining humorous circuit resonant frequencies under ideal conditions is f1, f2(f1＜ f2), respectively
It is C that correspondence joins humorous electric capacity1And C2(C1＞ C2), BW1, BW2For corresponding bandwidth.In frequency range (f1, f2) in, join humorous bandwidth for two and deposit
In three kinds of states：1. bandwidth has common factor state, 2. bandwidth critical condition, and 3. bandwidth is no occured simultaneously state.And 2. 1., in state, own
f1With f2Between frequency be all in and join within humorous circuit bandwidth, and 3. in state, some frequencies omit join humorous circuit bandwidth it
Outward, it therefore meets the condition that frequency between its resonant frequency point all covers is by the humorous circuit bandwidth of joining of adjacent resonant frequencies：
f2-f1≤(BW1+BW2)/2 (3)
4) error according to actual capacitance and ideal capacitance described in, determines that the method joining humorous capacitance selection refers to for reality
Border capacitor's capacity error causes the problem joining humorous frequency shift (FS), by obtaining the restriction relation between adjacent resonance frequency, finally
Obtain the relation between adjacent capacitor.It is analyzed as follows further：
Under physical condition, capacitor's capacity error delta C/C causes resonance frequency shift, thus impact join humorous.Capacitance error is got over
Greatly, resonance frequency shift degree is more serious.Fig. 3 be physical condition under capacitor's capacity error delta C/C cause resonance frequency shift with
Join humorous bandwidth change schematic diagram.Resonance frequency shift degree Δ f with the relation of capacitor's capacity error delta C/C is：
Or
As shown in figure 4, arbitrary neighborhood electric capacity C1And C2(C1＞ C2) actual resonance frequency and theoretical resonance frequency f1, f2's
Four kinds of shift state.Wherein, under A condition, actual resonance frequency side-play amount is respectively+Δ f1With-Δ f2；Under B state, actual humorous
Vibration frequency side-play amount is respectively+Δ f1With+Δ f2；Under C-state, actual resonance frequency side-play amount is respectively-Δ f1,-Δ f2；D shape
Under state, actual resonance frequency side-play amount is respectively-Δ f1,+Δ f2.
Under A condition, make f1With f2In the range of all frequencies all joined the condition that humorous circuit bandwidth covers and be
Δf2＜ 1/2BW2′ (5)
Δf1＜ 1/2BW1′ (6)
f2-f1-Δf1-Δf2≤1/2(BW1′+BW2′) (7)
Wherein BW1', BW2' accordingly join humorous circuit bandwidth under A condition for it.
Under B state, make f1With f2In the range of all frequencies all joined the condition that humorous circuit bandwidth covers and be：
Δf1＜ 1/2BW1′ (8)
f2-f1-Δf1≤1/2(BW1′+BW2′) (9)
Wherein BW1', BW2' accordingly join humorous circuit bandwidth under B state for it.
Under C-state, make f1With f2In the range of all frequencies all joined the condition that humorous circuit bandwidth covers and be：
Δf2＜ 1/2BW1′ (10)
Wherein BW1', BW2' accordingly join humorous circuit bandwidth under C-state for it.
Under D-state, make f1With f2In the range of all frequencies all joined the condition that humorous circuit bandwidth covers and be：
f2-f1≤1/2(BW1′+BW2′) (12)
Wherein BW1', BW2' accordingly join humorous circuit bandwidth under D-state for it.
If therefore making frequency be must simultaneously meet the condition under tetra- kinds of virtual conditions of A, B, C, D by joining humorous bandwidth all standing.
And capacitor's capacity error delta C/C scope is 3%～10%.Condition (5), (6), (8) and (10) is permanent to be set up.Therefore condition only need to be discussed
(7)、(9)、(11)、(12).And formula (2) is brought into condition (7), (9), (11), (12) middle acquisition：
Under A condition, the condition of frequency all standing is：
Under B state, the condition of frequency all standing is：
Under C-state, the condition of frequency all standing is：
Under D-state, the condition of frequency all standing is：
f1 2πL/(R(1+ΔC/C))+f1+f2 2πL/(R(1-ΔC/C))-f2+r/2πL≥0 (16)
If assuming f in (13), (14), (15) and (16) formula2(larger resonant frequency in adjacent resonant frequencies) it is known that
Try to achieve f1The span of (less resonant frequency in adjacent resonant frequencies), and minimum of a value fminCan be tried to achieve by above-mentioned equation.
fmin＜ f1＜ f2(17)
Under A condition, resonant frequency f1Minimum of a value f1 minFormula is
Under B state, resonant frequency f2Minimum of a value f1 minFormula is
Under C-state, resonant frequency f2Minimum of a value f1 minFormula is
Under D-state, resonant frequency f2Minimum of a value f1 minFormula is
Therefore, actual join humorous in, if larger resonant frequency f in known adjacent resonant frequencies point2, you can to less resonance
Frequency f1Span be defined.Less resonant frequency f1It is all higher than above-mentioned minimum of a value, meet four kinds of virtual conditions simultaneously
Lower frequency is all joined humorous bandwidth and is covered.
Further (18) (21) formula analysis is found, f1As long as minimum of a value meet (21) formula, then necessarily satisfying for (18),
(19), (20) three formula, that is, in all conditions, (21) formula condition is the harshest, so in following analysis, only analysis meets
(21) result of formula.
As shown in figure 5, joining humorous circuit diagram for actual.Its breaker in middle, by Digital Signals, joins humorous electricity for decision
Hold whether with join humorous circuit and be connected.If the smaller capacitive in known adjacent capacitor, the resonant frequency of this smaller capacitive is as adjacent
Larger resonant frequency f in resonant frequency2, less resonant frequency f is obtained by (21) formula1Minimum of a value f1 min, itsCorresponding
Capacitance is the maximum of larger capacitance in adjacent capacitor.Therefore compared with low-capacitance in known adjacent capacitor, you can to larger in adjacent
The span of electric capacity is judged.Therefore pass through the relation between adjacent resonant frequencies, between final acquisition adjacent capacitor
Relation.It should be noted that originally join humorous method need to determine successively according to joining humorous capacitor's capacity size.
The present invention to join humorous method as follows：
1st, determine and join humorous Circuits System parameter：Probe inductance L inductance value, internal resistance r resistance of popping one's head in, build-out resistor R resistance, electric capacity
Capacitance error delta C/C, scope f of systematic survey frequencymin, fmax.
2nd, determine fixing minimum capacity Cmin, fixing minimum according to the maximum value calculation of proton-precession magnetometer measurement range
Electric capacity.
3rd, determine join be switched on and off control in humorous circuit join humorous electric capacity.
A humorous electric capacity C is joined in () determination1.With join humorous electric capacity C1Two relevant adjacent capacitor are respectively fixing minimum capacity Cmin
With Cmin+C1.CminFor fixing minimum capacity, and known to capacitance.By CminCorresponding resonant frequency is as larger resonant frequency f2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 min, and obtain larger capacitance Cmin+C1Maximum C1 max.I.e. C1
Span be：C1≤C1 max-Cmin.Select to join humorous electric capacity C in the range of this1Frequency all standing all can be met.
B humorous electric capacity C is joined in () determination2.With join humorous electric capacity C2Two related adjacent capacitor are Cmin+C1With Cmin+C2.Cmin+C1
For smaller capacitive in adjacent capacitor, and known to capacitance.By Cmin+C1Corresponding resonant frequency is as larger resonant frequency f2.Pass through
(21) formula, using said method, obtains larger capacitance C in adjacent capacitormin+C2Maximum C2 max.I.e. C2Span：C2
≤C2 max-Cmin.Select to join humorous electric capacity C in the range of this2Frequency all standing all can be met.
C humorous electric capacity C is joined in () determination3.With join humorous electric capacity C3Two related adjacent capacitor are respectively Cmin+C2With Cmin+C3.
Cmin+C2For the smaller capacitive of adjacent capacitor, and known to capacitance.By Cmin+C2Corresponding resonant frequency is as larger resonant frequency
f2.By (21) formula, using said method, obtain larger capacitance C in adjacent capacitormin+C3Maximum C3 max.I.e. C3Value
Scope is：C3≤C3 max-Cmin.Select to join humorous electric capacity C in the range of this3Frequency all standing all can be met.By that analogy, obtain
Remainder joins humorous electric capacity, until meeting minimum measurement range.
(d) choose all after joining humorous electric capacity, need to check all adjacent join whether all meet between humorous electric capacity actual complete
Cover.Assist software using MATLAB or EXCEL etc., the speed calculating capacitance scope will be greatly improved, make selection join humorous electric capacity
More convenient and quicker.
Analyzed by above, the specific technical scheme obtaining the present invention is as follows.
A kind of method that humorous electric capacity joined by optimum choice proton magnetometer, has determination to join humorous Circuits System parameter, determine and fix
Minimum capacity Cmin, gradually determine and join the process of humorous electric capacity；
Humorous Circuits System parameter is joined in described determination, is by LC parallel connection frequency selection circuit (joining humorous circuit) in reception system
The probe inductance L inductance value that determines, probe internal resistance r resistance, build-out resistor R resistance, capacitor's capacity error delta C/C and according to institute's geodetic
Magnetic field range determines scope f of systematic survey frequencymin～fmax；
Minimum capacity C is fixed in described determinationmin, it is corresponding according to the maximum of proton-precession magnetometer measurement range
Maximum measurement frequency fmaxCalculate fixing minimum capacity Cmin；
Humorous electric capacity is joined in described gradually determination, is to fix minimum capacity CminBased on determine and adjacent join humorous electric capacity C1,
Again with Cmin+C1Based on determine and C1Adjacent joins humorous electric capacity C2, with Cmin+C2Based on determine and C2Adjacent joins humorous electric capacity
C3... with Cmin+Ci-1Based on determine and Ci-1Adjacent joins humorous electric capacity Ci..., until determining and minimum measurement frequency fminRight
The maximum answered joins humorous electric capacity Cmax；Respectively join humorous electric capacity C in joining humorous circuit2～CmaxIt is switched on and off control；Specific determination
Join humorous electric capacity CiMethod be：
According to larger resonant frequency fi-1Calculating is adjacent resonant frequency fiMinimum of a value fimin, computing formula is as follows：
According to fiminIt is calculated corresponding maximum and join humorous electric capacity Cimax, then need to join humorous electric capacity C by what switch introducedi
Meet Ci≤Ci max-Cmin.
Join in the method for humorous electric capacity in optimum choice proton magnetometer, humorous Circuits System parameter is joined in described determination, permissible
Be probe inductance L inductance value be 17.4mH～35mH, probe internal resistance r resistance be 5.9 Ω～20 Ω, build-out resistor R resistance be 1K Ω
～10K Ω, capacitor's capacity error delta C/C≤5%, the scope 0.85kHz～3.83kHz of systematic survey frequency；For about
The geomagnetic field measuring scope of 20000nT～90000nT.
The present invention be directed to limited capacitance combination join humorous occur that some frequencies are not joining the situation within humorous circuit bandwidth, carry
Go out according to joining the method that humorous circuit bandwidth optimum choice joins humorous electric capacity, making entirely to join humorous circuit bandwidth can be with all standing system band
Wide；It is simultaneous for the situation that there is error between actual capacitance and ideal capacitance, the circuit that analysis obtains comprising capacitance error is joined
Humorous method, solves and joins the transmitting skew of harmonics rate due to what capacitor's capacity error led to, thus some Frequency points not in electricity
Problem in the bandwidth range of road.This method can achieve that different measuring scope, to the selection joining humorous electric capacity, improves later stage measurement signal
Precision.
Brief description
Fig. 1：Join humorous circuit theory diagrams；
Fig. 2：Under ideal conditions, arbitrary neighborhood electric capacity joins three kinds of states in its ghz area for the humorous bandwidth；
Fig. 3：The resonance frequency shift that under physical condition, capacitor's capacity error leads to；
Fig. 4：Four kinds of shift state of the actual resonance frequency of arbitrary neighborhood electric capacity and theoretical resonance frequency under physical condition；
Fig. 5：Actual join humorous circuit diagram.
Specific embodiment
Embodiment 1：Low reactance-resistance ratio joins humorous Circuits System
Proton-precession magnetometer magnetic-field measurement scope be 20000nT～90000nT, frequency measurement scope be 850～
3830Hz.Probe inductance L is 17.4mH, and probe internal resistance r is 5.9 Ω, and build-out resistor R is 1K Ω, joins humorous electric capacity poly- using correction
Propylene electric capacity, error is ± 5%.
1st, determine fixing minimum capacity Cmin.According to magnetic field maximum measurement range 90000nT, obtain fixing minimum capacity Cmin
For 100nF, it all the time with join humorous circuit and be connected.
2nd, determine join be switched on and off control in humorous circuit join humorous electric capacity.
A humorous electric capacity C is joined in () determination1：With join humorous electric capacity C1Related two adjacent, and to join humorous electric capacity be CminWith Cmin+C1.Cmin
For in adjacent capacitor compared with low-capacitance, and Cmin=100nF, respective resonant frequencies are 3830Hz, as larger in adjacent resonant frequencies
Resonant frequency f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 2623Hz, that is, obtain corresponding adjacent electricity
In appearance, the maximum of larger capacitance value is 211.6nF.Join humorous electric capacity C1Span be C1＜ 111.6nF, may be selected to join humorous electricity
Hold for 100nF.
B humorous electric capacity C is joined in () determination2：With join humorous electric capacity C2Two related adjacent capacitor are Cmin+C1With Cmin+C2.Cmin+C1
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2698Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 2042Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is 349nF.Join humorous electric capacity C2Span be C2≤ 249nF, may be selected to join humorous electric capacity is 249nF.
C humorous electric capacity C is joined in () determination3：With join humorous electric capacity C3Two related adjacent capacitor Cmin+C2With Cmin+C3.Cmin+C2For
Compared with low-capacitance in adjacent capacitor, its resonant frequency is 2042Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 1635Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is 544nF.Join humorous electric capacity C3Span be C3≤444nF.May be selected to join humorous electric capacity C3For 440nF.
D humorous electric capacity C is joined in () determination4：With join humorous electric capacity C4Two related adjacent capacitor are Cmin+C3With Cmin+C4.Cmin+C3
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1642Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 1358Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is respectively 789nF.Join humorous electric capacity C4Span be C4≤689nF.May be selected to join humorous electric capacity C4For 685nF.
E humorous electric capacity C is joined in () determination5：With join humorous electric capacity C5Two related adjacent capacitor are Cmin+C4With Cmin+C5.Cmin+C4
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1362Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 1150Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is respectively 1100.5nF.Join humorous electric capacity C5Span be C5≤1000.5nF.May be selected to join humorous electric capacity and be
1000nF.
F humorous electric capacity C is joined in () determination6：With join humorous electric capacity C6Two related adjacent capacitor are Cmin+C5With Cmin+C6.Cmin+C5
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1150Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 984Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is respectively 1502nF.Join humorous electric capacity C6Span be C5≤1402nF.May be selected to join humorous electric capacity is 1400nF.
G humorous electric capacity C is joined in () determination7：With join humorous electric capacity C7Two related adjacent capacitor are Cmin+C6With Cmin+C7.Cmin+C6
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 984Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 849Hz, that is, obtain larger capacitance value in corresponding adjacent capacitor
Maximum is respectively 2017nF.Join humorous electric capacity C7Span be C7≤1917nF.May be selected to join humorous electric capacity is 1900nF.This
When system resonance frequencies be 853Hz, fully met requirement
3rd, determine and join humorous electric capacity using following 7：
| Join humorous electric capacity | Cmin | C1 | C2 | C3 | C4 | C5 | C6 | C7 |
| Capacitance (nF) | 100 | 100 | 249 | 440 | 685 | 1000 | 1400 | 1900 |
| Resonant frequency (Hz) | 3830 | 2698 | 2042 | 1642 | 1362 | 1150 | 984 | 853 |
Embodiment 2：Humorous Circuits System is joined in high q-factor, high inductance, low-power consumption
Proton-precession magnetometer magnetic-field measurement scope be 20000nT～90000nT, frequency measurement scope be 850～
3830Hz.Probe inductance L is 35mH, and probe internal resistance r is 20 Ω, and build-out resistor R is 10K Ω, joins humorous electric capacity using correction poly- third
Alkene electric capacity, error is ± 3%.
1st, determine fixing minimum capacity Cmin.According to magnetic field maximum measurement range 90000nT, obtain fixing minimum capacity Cmin
For 49.3nF, it all the time with join humorous circuit and be connected.
2nd, determine join be switched on and off control in humorous circuit join humorous electric capacity.
A humorous electric capacity C is joined in () determination1：With join humorous electric capacity C1Related two adjacent, and to join humorous electric capacity be CminWith Cmin+C1.Cmin
For in adjacent capacitor, compared with low-capacitance, respective resonant frequencies are 3830Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 3493.7Hz, obtaining corresponding electric capacity is 59.3nF.Join humorous
Electric capacity C1Span be C1≤10.0nF.May be selected to join humorous electric capacity is 10.0nF.
B humorous electric capacity C is joined in () determination2：With join humorous electric capacity C2Two related adjacent capacitor are Cmin+C1With Cmin+C2.Cmin+C1
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 3493.7Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
Cross ((21) formula less resonant frequency f of acquisition1Minimum of a value f1 minFor 3201.9Hz, obtaining corresponding electric capacity is 70.6nF, joins humorous
Electric capacity C2Span be C2＜ 21.3nF.May be selected to join humorous electric capacity is 20nF.
C humorous electric capacity C is joined in () determination3：With join humorous electric capacity C3Two related adjacent capacitor Cmin+C2With Cmin+C3.Cmin+C2For
Compared with low-capacitance in adjacent capacitor, its resonant frequency is 3231.6Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f respectively1Minimum of a value f1 minFor 2970Hz, obtaining corresponding electric capacity is 82.0nF, joins humorous electricity
Hold C3Span be C3≤32.7nF.May be selected to join humorous electric capacity is 30nF.
D humorous electric capacity C is joined in () determination4：With join humorous electric capacity C4Two related adjacent capacitor are Cmin+C3With Cmin+C4.Cmin+C3
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 3021Hz, as resonant frequency f larger in adjacent resonant frequencies2.Pass through
(21) formula obtains less resonant frequency f1Minimum of a value f1 minFor 2784.7Hz, that is, obtaining corresponding electric capacity is 93.3nF, joins humorous electricity
Hold C4Span be C4≤44nF.May be selected to join humorous electric capacity is 44nF.
E humorous electric capacity C is joined in () determination5：With join humorous electric capacity C5Two related adjacent capacitor are Cmin+C4With Cmin+C5.Cmin+C4
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2784.7Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 2572.9Hz, that is, obtaining corresponding electric capacity is 109.3nF, joins humorous
Electric capacity C5Span be C5＜ 60nF.May be selected to join humorous electric capacity is 60nF.
F humorous electric capacity C is joined in () determination6：With join humorous electric capacity C6Two related adjacent capacitor are Cmin+C5With Cmin+C6.Cmin+C5
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2572.9Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 2381.3Hz, that is, obtaining corresponding electric capacity is 127.6nF, joins humorous
Electric capacity C6Span be C6≤ 78.3nF, may be selected to join humorous electric capacity is 78nF.
G humorous electric capacity C is joined in () determination7：With join humorous electric capacity C7Two related adjacent capacitor are Cmin+C6With Cmin+C7.Cmin+C6
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2384.4Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 2209.3Hz, that is, obtaining corresponding electric capacity is 148.3nF, joins humorous
Electric capacity C7Span be C7＜ 99nF.May be selected to join humorous electric capacity is 99nF.
H humorous electric capacity C is joined in () determination8：With join humorous electric capacity C8Two related adjacent capacitor are Cmin+C7With Cmin+C8.Cmin+C7
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2209.3Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 2048.3Hz, obtaining corresponding electric capacity is 172.5nF.Join humorous electricity
Hold C8Span be C8≤123.2nF.May be selected to join humorous electric capacity is 122nF.
I humorous electric capacity C is joined in () determination9：With join humorous electric capacity C9Two related adjacent capacitor are Cmin+C8With Cmin+C9.Cmin+C8
For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 2043.6Hz, as resonant frequency f larger in adjacent resonant frequencies2.Logical
(21) formula of crossing obtains less resonant frequency f1Minimum of a value f1 minFor 1894.8Hz, obtaining corresponding electric capacity is 201.6nF, joins humorous electricity
Hold C9Span be C9＜ 152.3nF, may be selected to join humorous electric capacity is 152nF.
J humorous electric capacity C is joined in () determination10：With join humorous electric capacity C10Two related adjacent capacitor are Cmin+C9With Cmin+C10.Cmin
+C9For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1896.1Hz, as resonant frequency f larger in adjacent resonant frequencies2.
Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1753Hz, obtaining electric capacity is 235.5nF, joins humorous electric capacity C10
Span be C10＜ 186.2nF, may be selected to join humorous electric capacity is 186nF.
K humorous electric capacity C is joined in () determination11：With join humorous electric capacity C11Two related adjacent capacitor are Cmin+C10With Cmin+C11.Cmin
+C10For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1753.8Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1623.2Hz, obtaining corresponding electric capacity is 274.7nF,
Join humorous electric capacity C11Span be C11＜ 225.4nF, may be selected to join humorous electric capacity is 225nF.
L humorous electric capacity C is joined in () determination12：With join humorous electric capacity C12Two related adjacent capacitor are Cmin+C11With Cmin+C12.Cmin
+C11For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1624.3Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1501.4Hz, obtaining corresponding electric capacity is 321nF, joins
Humorous electric capacity C12Span be C12＜ 271.7nF, may be selected to join humorous electric capacity is 270nF.
M humorous electric capacity C is joined in () determination13：With join humorous electric capacity C13Two related adjacent capacitor are Cmin+C12With Cmin+C13.Cmin
+C12For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1505.5Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1388.6Hz, obtaining corresponding electric capacity is 375.3nF,
Join humorous electric capacity C13Span be C13＜ 326nF, may be selected to join humorous electric capacity is 326nF.
N humorous electric capacity C is joined in () determination14：With join humorous electric capacity C14Two related adjacent capacitor are Cmin+C14With Cmin+C14.Cmin
+C13For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1388.6Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1277.1Hz, obtaining corresponding electric capacity is 443.7nF,
Join humorous electric capacity C14Span be C14＜ 394.4nF, may be selected to join humorous electric capacity is 394nF.
O humorous electric capacity C is joined in () determination15：With join humorous electric capacity C15Two related adjacent capacitor are Cmin+C14With Cmin+C15.Cmin
+C14For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1277.7Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1170.8Hz, obtaining corresponding electric capacity is 528.0nF,
Join humorous electric capacity C15Span be C15＜ 478.6nF, may be selected to join humorous electric capacity is 478nF.
P humorous electric capacity C is joined in () determination16：With join humorous electric capacity C16Two related adjacent capacitor are Cmin+C15With Cmin+C16.Cmin
+C15For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1171.5Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 1068.5Hz, obtaining corresponding electric capacity is 633.9nF,
Join humorous electric capacity C16Span be C16＜ 584.6nF, may be selected to join humorous electric capacity is 584nF.
Q humorous electric capacity C is joined in () determination17：With join humorous electric capacity C17Two related adjacent capacitor are Cmin+C16With Cmin+C17.Cmin
+C16For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 1068.5Hz, as resonant frequency larger in adjacent resonant frequencies
f2.Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 968.8Hz, obtaining corresponding electric capacity is 771.1nF, joins
Humorous electric capacity C17Span be C17＜ 721.8nF, may be selected to join humorous electric capacity is 721nF.
R humorous electric capacity C is joined in () determination18：With join humorous electric capacity C18Two related adjacent capacitor are Cmin+C17With Cmin+C18.Cmin
+C17For in adjacent capacitor, compared with low-capacitance, its resonant frequency is 969.3Hz, as resonant frequency f larger in adjacent resonant frequencies2.
Less resonant frequency f is obtained by (21) formula1Minimum of a value f1 minFor 872.3Hz, obtaining corresponding electric capacity is 951.0nF, joins humorous
Electric capacity C18Span be C18＜ 902nF, may be selected to join humorous electric capacity C18For 902nF.This Time Bandwidth is 107Hz, low cutoff
Frequency reaches 818.3 and has been far below 850Hz, completes to join in full bandwidth humorous.
3 it is thus determined that join humorous electric capacity using following 18：
| Join humorous electric capacity | Cmin | C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 |
| Capacitance (nF) | 49.3 | 10 | 20 | 30 | 44 | 60 | 78 | 99 | 122 | 152 |
| Resonant frequency (Hz) | 3830 | 3494 | 3232 | 3202 | 2784 | 2572 | 2384 | 2209 | 2043 | 1896 |
| Join humorous electric capacity | C10 | C11 | C12 | C13 | C14 | C15 | C16 | C17 | C18 |
| Capacitance (nF) | 186 | 225 | 270 | 326 | 394 | 478 | 584 | 721 | 902 |
| Resonant frequency (Hz) | 1753 | 1624 | 1505 | 1388 | 1277 | 1171 | 1068 | 963 | 872 |
In the above embodiments, in the circuit determining proton-precession magnetometer magnetic-field measurement scope, the fixation of probe
It is possible to preferably join humorous electric capacity on the basis of the parameter of element, Q value size.
Claims (2)
1. a kind of method that humorous electric capacity joined by optimum choice proton magnetometer, has determination to join humorous Circuits System parameter, determine and fix
Small capacitances Cmin, gradually determine and join the process of humorous electric capacity；
Humorous Circuits System parameter is joined in described determination, is the probe inductance L being determined by the LC parallel connection frequency selection circuit in reception system
Inductance value, probe internal resistance r resistance, build-out resistor R resistance, capacitor's capacity error delta C/C and system is determined according to institute geodetic magnetic field range
Scope f of system measurement frequencymin～fmax；
Minimum capacity C is fixed in described determinationmin, it is corresponding according to the maximum of proton-precession magnetometer measurement range
Big measurement frequency fmaxCalculate fixing minimum capacity Cmin；
Humorous electric capacity is joined in described gradually determination, is to fix minimum capacity CminBased on determine and adjacent join humorous electric capacity C1, then with
Cmin+C1Based on determine and C1Adjacent joins humorous electric capacity C2, with Cmin+C2Based on determine and C2Adjacent joins humorous electric capacity C3...
With Cmin+Ci-1Based on determine and Ci-1Adjacent joins humorous electric capacity Ci..., until determining and minimum measurement frequency fminCorresponding
Maximum joins humorous electric capacity Cmax；Respectively join humorous electric capacity C in joining humorous circuit2～CmaxIt is switched on and off control；Specific determination is joined humorous
Electric capacity CiMethod be：
According to resonant frequency fi-1Calculate resonant frequency f being adjacentiMinimum of a value fimin, computing formula is as follows：
According to fiminIt is calculated corresponding maximum and join humorous electric capacity Cimax, then need to join humorous electric capacity C by what switch introducediMeet Ci
≤Cimax-Cmin.
2. optimum choice proton magnetometer according to claim 1 join humorous electric capacity method it is characterised in that described really
Surely join humorous Circuits System parameter, probe inductance L inductance value be 17.4mH～35mH, probe internal resistance r resistance be 5.9 Ω～20 Ω,
Distribution hinder R resistance be 1K Ω～10K Ω, capacitor's capacity error delta C/C≤5%, systematic survey frequency scope 0.85kHz～
3.83kHz；Geomagnetic field measuring scope for 20000nT～90000nT.
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| KR101014370B1 (en) * | 2008-12-22 | 2011-02-15 | 한국지질자원연구원 | Proton precession magnetometer sensor measurable in all direction |
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