CN108983297B - A kind of surface em signal deteching circuit - Google Patents
A kind of surface em signal deteching circuit Download PDFInfo
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- CN108983297B CN108983297B CN201810621668.6A CN201810621668A CN108983297B CN 108983297 B CN108983297 B CN 108983297B CN 201810621668 A CN201810621668 A CN 201810621668A CN 108983297 B CN108983297 B CN 108983297B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
Abstract
The invention discloses a kind of surface em signal deteching circuits, comprising: two impedance matching circuits are connected, for input signal to be coupled into Infirmness signal detecting circuit with input interface；Two low-pass filter circuits, each low-pass filter are connected with an impedance matching circuit, for filtering to input signal；Multiple active filter circuits, multiple active filter circuits are equally divided into two groups, each group includes multiple active filter circuits, each group of active filter circuit is connected with a low-pass filter circuit, active filter circuit in each group is in parallel, and the signal that multiple active filter circuits are used to export low-pass filter filters；Two optional attenuator circuits, for adjusting the ground resistance of Infirmness signal detecting circuit；Differential amplifier circuit is connected with optional attenuator circuit；Two optional gain circuitries, are connected with differential amplifier circuit；A/D converter circuit is connected with optional gain circuitry.The embodiment of the present invention can more accurately detect weak signal.
Description
Technical field
The present invention relates to electrical prospecting field, in particular to a kind of surface em signal deteching circuit.
Background technique
Electrical prospecting is one of effective means of mineral resources, many kinds of, adaptable, is widely used in
The fields such as Sounding Research On Deep, mineral resources exploration and the hydrology and engineering investigation.
For the frequency range of electrical prospecting usually in DC-10kHz, dynamic range is wider, but the electromagnetic field signal of its detection
It is very faint, usually in several microvolts or so.And the transmission range of electrical prospecting is farther out, and measuring signal will be by several meters even
Tens meters of cable is transferred to receiver, it is easy to by the interference of various noises, useful signal be caused to be submerged.
Therefore how development for frequency domain electromagnetic methods multichannel receiver designs a kind of high-precision, low noise, wideband
The Infirmness signal detecting circuit of band is main problem.
Summary of the invention
In view of this, the embodiment of the present application provides a kind of surface em signal deteching circuit characterized by comprising
Two impedance matching circuits, are connected with the input interface, for input signal to be coupled into the weak signal
Detection circuit；Two low-pass filter circuits, each low-pass filter circuit are connected with an impedance matching circuit, for institute
State input signal filtering；Multiple active filter circuits, the multiple active filter circuit are equally divided into two groups, each group of packet
Multiple active filter circuits are included, each group of active filter circuit is connected with a low-pass filter circuit, in each group
Active filter circuit is in parallel, and the signal that the multiple active filter circuit is used to export the low-pass filter filters；
Two optional attenuator circuits, each optional attenuator circuit is connected with one group of active filter circuit, described weak for adjusting
The ground resistance of signal deteching circuit；Differential amplifier circuit is connected with the optional attenuator circuit, for amplifying the active filter
The signal of wave device circuit output；Two optional gain circuitries, are connected with the differential amplifier circuit, put for amplifying the difference
The output signal of big circuit；A/D converter circuit is connected with the optional gain circuitry, for exporting the optional gain circuitry
Analog signal be converted into digital signal.
Preferably, the low-pass filter circuit includes: adjustable input resistance Rg, and the first of the adjustable input resistance Rg
End be connected with the impedance matching circuit, the second end of Rg is connected with the first end of inductance L, the second end of the Rg also with capacitor
The first end of C0 is connected；The capacitor C0, second end ground connection；The second end of the inductance L, the inductance L pass through switching capacity
Group C1 ground connection；Amplifier U1, the reverse input end of the amplifier U1 are connected with the output end of the amplifier U1, the amplification
The positive input of device U1 is connected with the second end of the inductance L, active filter described in the output end of the amplifier U1 and one group
Wave device circuit is connected；The positive input of amplifier U2, the amplifier U2 are connected with the first end of selection sub-circuit, described to put
The reverse input end of big device U2 is connected with the output end of the amplifier U2, the output end of the amplifier U2 also with the switch
Capacitance group C1 is connected with the connected node of capacitor C0；The selection sub-circuit, including first choice branch R0, the second selection branch
The second end of sub-circuit is selected to be connected with the output end of the amplifier U1 described in R0' and switch S8, the first of the switch S8
End is connected with the positive input of the amplifier U2, and the second end ground connection of the switch S8, the selection sub-circuit is for giving
The amplifier U2 provides different ground resistances.
Preferably, the switching capacity group C1 includes: switch S1 and capacitor C2, the first end of the switch S1 and described is put
The positive input of big device U1 is connected, and the second end of the switch S1 is connected with the first end of the capacitor C2, and the of the C3
Two ends are connected with the output end of the amplifier U2；Switch S2 and capacitor C3, the first end of the switch S2 and the amplifier
The positive input of U1 is connected, and the second end of the switch S2 is connected with the first end of the capacitor C3, the second end of the C4
It is connected with the output end of the amplifier U2；Switch S3 and capacitor C4, the first end of the switch S3 and the amplifier U1's
Positive input is connected, and the second end of the switch S3 is connected with the first end of the capacitor C4, the second end of the C5 and institute
The output end for stating amplifier U2 is connected；Switch S4 and capacitor C5, the forward direction of the first end of the switch S4 and the amplifier U1
Input terminal is connected, and the second end of the switch S4 is connected with the first end of the capacitor C5, and the second end of the C6 is put with described
The output end of big device U2 is connected；The positive input of switch S5 and capacitor C6, the first end of the switch S5 and the amplifier U1
End is connected, and the second end of the switch S5 is connected with the first end of the capacitor C6, the second end of the C7 and the amplifier
The output end of U2 is connected.
Preferably, the first choice branch R0 includes: switch S6, the first end of the switch S6 and the amplifier U2
Positive input be connected, the second end of the switch S6 is connected with the first end of capacitor C8；The capacitor C8, the second termination
Ground；Resistance R3, the first end of the resistance R3 are connected with the first end of the capacitor C8, the second end and resistance of the resistance R3
The first end of R2 is connected；The second end of resistance R2, the resistance R2 are grounded；Capacitor C7, the first end of the capacitor C7 with it is described
The second end of resistance R3 is connected, and the second end of the capacitor C7 is connected with the output end of the amplifier U1；Second selection
Branch R0 includes: switch S7, and the first end of the switch S7 is connected with the positive input of the amplifier U2, the switch S7
Second end be connected with the first end of capacitor C10；The capacitor C10, second end ground connection；Resistance R5, the first of the resistance R5
End is connected with the first end of the capacitor C10, and the second end of the resistance R5 is connected with the first end of resistance R4；Resistance R4, institute
State the second end ground connection of resistance R4；Capacitor C9, the first end of the capacitor C9 are connected with the second end of the resistance R5, the electricity
The second end for holding C9 is connected with the output end of the amplifier U1.
Preferably, each active filter circuit is connected by first switch S0 with the low-pass filter circuit.
Preferably, the active filter circuit includes: adjustable input resistance RX, and the first of the adjustable input resistance RX
End is connected with the first switch S0, and the second end of the adjustable input resistance RX is connected with resistance R11；The resistance R11, institute
It states the second end of resistance R11 while being connected with the first end of the capacitor C11, the first end of inductance L1；The capacitor C11, the
Two ends ground connection；The second end of the inductance L1, the inductance L1 are connected with the input terminal of capacitance switch sub-circuit；The capacitor is opened
Climax circuit, output end are connected with the optional attenuator circuit.
Preferably, the capacitance switch sub-circuit includes:
Switch S11 and capacitor C12, the first end of the switch S11 with it is described can attenuator circuit be connected, the switch S11
Second end be connected with the first end of capacitor C12, the second end of capacitor C12 ground connection；Switch S12 and capacitor C13, it is described to open
Close S12 first end with it is described can attenuator circuit be connected, the second end of the switch S12 is connected with the first end of capacitor C13, institute
State the second end ground connection of capacitor C13；Switch S13 and capacitor C14, the first end of the switch S13 with it is described can attenuator circuit phase
Even, the second end of the switch S13 is connected with the first end of capacitor C14, the second end ground connection of the capacitor C14；Switch S14 and
Capacitor C15, the first end of the switch S14 with it is described can attenuator circuit be connected, the second end of the switch S14 and capacitor C15
First end be connected, the second end of capacitor C15 ground connection；Switch S15 and capacitor C16, the first end of the switch S15 and institute
State can attenuator circuit be connected, the second end of the switch S15 is connected with the first end of capacitor C16, the second end of the capacitor C16
Ground connection.
Preferably, the detection circuit further includes two feed circuits, each feed circuit and one group of active power filtering
Device circuit in parallel.
Preferably, the feed circuit includes amplifier U3, the output end of the amplifier U3 by with one it is described low
Bandpass filter circuit is connected.
Preferably, the optional gain circuitry includes: switch XX, the first end of the switch XX and differential amplification electricity
Road is connected, and the second end of the switch XX is connected with AC coupling circuit；AC coupling circuit, the second end of the AC coupling circuit with
The optional gain is connected；Switch XY, the first end of the switch XY are connected with the differential amplifier circuit, the switch XY's
Second end is connected with DC coupling circuit；DC coupling circuit, the second end of the DC coupling circuit are connected with the optional gain；It can
Gain is selected, is connected with the A/D converter circuit.
In surface em signal deteching circuit provided by the embodiments of the present application, two stage filter is provided, it can be relatively narrow
It is filtered in frequency range to noisy weak signal, it can also be by being arranged the free transmission range of filter to lucky energy
All covering useful signals, when passing through narrow band filter with noisy signal, bandwidth becomes smaller, so that the noise except passband
Power is significantly decayed, to reduce the interference of noise and useful signal will not decay, further, additionally it is possible to according to
Actual ground resistance rate adjusts compensating electric capacity, can be realized optimal filtering characteristic always, so energy of the embodiment of the present invention
More accurately detect weak signal.
Detailed description of the invention
In order to more clearly explain the technical solutions in the embodiments of the present application, make required in being described below to embodiment
Attached drawing is briefly described, it should be apparent that, drawings in the following description are some embodiments of the invention, for this
For the those of ordinary skill of field, without creative efforts, it can also be obtained according to these attached drawings others
Attached drawing.
Fig. 1 is a kind of structural schematic diagram of surface em signal deteching circuit provided in an embodiment of the present invention；
Fig. 2 is a kind of schematic illustration of low-pass filter circuit provided in an embodiment of the present invention；
Fig. 3 is a kind of structural schematic diagram of low-pass filter circuit provided in an embodiment of the present invention；
Fig. 4 is a kind of structural schematic diagram of active filter circuit provided in an embodiment of the present invention.
Specific embodiment
To keep the purposes, technical schemes and advantages of the embodiment of the present application clearer, below in conjunction with the embodiment of the present invention
In attached drawing, the technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is only
It is only a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill
Personnel's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
In the description of the present invention, it is also necessary to which explanation is unless specifically defined or limited otherwise, term " setting ",
" coupling ", " connection " shall be understood in a broad sense, for example, " connection " can be and be directly connected to, can also by between intermediary in succession
It connects, can be the connection inside two elements.For the ordinary skill in the art, can understand as the case may be
The concrete meaning of above-mentioned term in the present invention.
Herein, relational terms such as first and second and the like be used merely to by an entity or operation with it is another
One entity or operation distinguish, and without necessarily requiring or implying between these entities or operation, there are any this reality
Relationship or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to the packet of nonexcludability
Contain, so that the process, method, article or equipment for including a series of elements not only includes those elements, but also including
Other elements that are not explicitly listed, or further include for elements inherent to such a process, method, article, or device.
In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that including the element
Process, method, article or equipment in there is also other identical elements.
The embodiment of the invention discloses a kind of surface em signal deteching circuits, can more accurately detect light current magnetic field
Signal is as shown in Figure 1 the structural schematic diagram of the surface em signal deteching circuit of the embodiment of the present invention, comprising:
Two impedance matching circuits 101, are connected with input interface, examine for input signal to be coupled into the weak signal
Slowdown monitoring circuit, the input interface is for receiving field source signal to be measured.
Two low-pass filter circuits 102, each low-pass filter circuit 102 are connected with an impedance matching circuit 101,
For being filtered to the input signal.
Multiple active filter circuits 103, the multiple active filter circuit 103 are equally divided into two groups, each group of packet
Multiple active filter circuits 103 are included, each group of active filter circuit 103 is connected with a low-pass filter circuit 102, often
Each active filter circuit 103 in one group is in parallel, and the multiple active filter circuit 103 is used for the low-pass filtering electricity
The signal filtering of road output.
Two optional attenuator circuits 104, each optional attenuator circuit are connected with one group of active filter circuit 103,
For adjusting the ground resistance of the light current magnetic field signal detection circuit.
Differential amplifier circuit 105 is connected, for amplifying the optional attenuator circuit 104 with the optional attenuator circuit 104
The signal of output.
Two optional gain circuitries 106, are connected with the differential amplifier circuit 105, for amplifying the differential amplification electricity
The differential signal that road 105 exports.Previous stage signal is amplified again by the gain circuitry 106, this multistage amplification
The stability and common-mode signal rejection ability of gain can be improved.
A/D converter circuit 107 is connected with the optional gain circuitry 106, for exporting the optional gain circuitry 106
Analog signal be converted into digital signal.
In electrical prospecting field, useful signal frequency is generally within the scope of DC-10kHz, and various noises are then dispersed in very
On wide frequency band.In order to inhibit noise jamming and ground resistance to change the influence to fixed filters cut-off frequency point, it is preferred that
In one embodiment of the invention, the low-pass filter circuit 102 is a kind of 2 ranks with bandpass filter compensation
Sallen-Key low-pass filter, this structure can be used to the amplitude-frequency characteristic of stable filter.Specifically, as shown in Fig. 2, described
Low-pass filter circuit 102 includes:
The first end of adjustable input resistance Rg, the adjustable input resistance Rg are connected with the impedance matching circuit 101, Rg
Second end be connected with the first end of inductance L, the second end of the Rg is also connected with the first end of capacitor C0；The capacitor C0's
Second end ground connection；The second end of the inductance L is grounded by switching capacity group C1.
Amplifier U1, the reverse input end of the amplifier U1 are connected with the output end of the amplifier U1, the amplification
The positive input of device U1 is connected with the second end of the inductance L, active filter described in the output end of the amplifier U1 and one group
Wave device circuit 103 is connected.
The positive input of amplifier U2, the amplifier U2 are connected with the first end of selection sub-circuit, the amplifier
The reverse input end of U2 is connected with the output end of the amplifier U2, the output end of the amplifier U2 also with the switching capacity
Group C1 is connected with the connected node of capacitor C0.
The selection sub-circuit, including selection son electricity described in first choice branch R0, the second selection branch R0' and switch S8
The second end on road is connected with the output end of the amplifier U1, and the first end of the switch S8 and the forward direction of the amplifier U2 are defeated
Enter end to be connected, the second end ground connection of the switch S8, the selection sub-circuit is used to provide different connect to the amplifier U2
Ground resistance.
The output characteristics of filter described in Fig. 2 by ground resistance variation influenced it is smaller, according to introduce feedback principle, be intended to
Some amount in stabilizing circuit then uses the negative-feedback of the amount.The negative-feedback that low-pass filter introduces is bandpass filter, band logical filter
The centre frequency of wave device is to be configured according to measuring signal frequency band, in one embodiment of the invention, the centre frequency
For 10kHz, the cutoff frequency of low-pass filter can thus be stablized in 10kHz.Preferably, one embodiment of the present of invention is also
Alternative feedback network bandpass filter is provided, to adapt to different measurement demands.
In electrical prospecting method, the bandwidth used is DC-10kHz, so having to guarantee system when designing circuit
Bandwidth be higher than 10kHz.Due to the presence of ground resistance, the cutoff frequency of low-pass filter can be made to change, ground connection electricity
Resistance is bigger, and the cutoff frequency of low-pass filter is lower.In the embodiment of the present invention, ground resistance is no more than the Europe 2K when general measure
Nurse, when the especially weak more difficult measurement of signal, ground resistance is no more than 5K ohm.
The bandpass filter feed circuit of design of the embodiment of the present invention, can effectively inhibit to lead to low pass due to ground resistance
The rapid decrease of filter cutoff frequency, when not feeding back, several hundred ohm of ground resistance can make the cutoff frequency of filter
Rate is lower than 10kHz.And when there is feedback, ground resistance can suitably increase.High center frequency is selected when ground resistance is bigger
Bandpass filter.
Fig. 3 show the structural schematic diagram of the low-pass filter circuit 102 of the embodiment of the present invention, with reference to shown in Fig. 2, Fig. 3,
The switching capacity group C1 includes:
Switch S1 and capacitor C2, the first end of the switch S1 is connected with the positive input of the amplifier U1, described
The second end of switch S1 is connected with the first end of the capacitor C2, the output end phase of the second end of the C2 and the amplifier U2
Even；
Switch S2 and capacitor C3, the first end of the switch S2 is connected with the positive input of the amplifier U1, described
The second end of switch S2 is connected with the first end of the capacitor C3, the output end phase of the second end of the C3 and the amplifier U2
Even；
Switch S3 and capacitor C4, the first end of the switch S3 is connected with the positive input of the amplifier U1, described
The second end of switch S3 is connected with the first end of the capacitor C4, the output end phase of the second end of the C4 and the amplifier U2
Even；
Switch S4 and capacitor C5, the first end of the switch S4 is connected with the positive input of the amplifier U1, described
The second end of switch S4 is connected with the first end of the capacitor C5, the output end phase of the second end of the C5 and the amplifier U2
Even；
Switch S5 and capacitor C6, the first end of the switch S5 is connected with the positive input of the amplifier U1, described
The second end of switch S5 is connected with the first end of the capacitor C6, the output end phase of the second end of the C6 and the amplifier U2
Even.
As shown in figure 3, the first choice branch R0 includes:
Switch S6, the first end of the switch S6 are connected with the positive input of the amplifier U2, the switch S6's
Second end is connected with the first end of capacitor C8；
The capacitor C8, second end ground connection；
Resistance R3, the first end of the resistance R3 are connected with the first end of the capacitor C8, the second end of the resistance R3
It is connected with the first end of resistance R2；
The second end of resistance R2, the resistance R2 are grounded；
Capacitor C7, the first end of the capacitor C7 are connected with the second end of the resistance R3, the second end of the capacitor C7
It is connected with the output end of the amplifier U1；
It is described second selection branch R0 include:
Switch S7, the first end of the switch S7 are connected with the positive input of the amplifier U2, the switch S7's
Second end is connected with the first end of capacitor C10；
The capacitor C10, second end ground connection；
Resistance R5, the first end of the resistance R5 are connected with the first end of the capacitor C10, the second end of the resistance R5
It is connected with the first end of resistance R4；
The second end of resistance R4, the resistance R4 are grounded；
Capacitor C9, the first end of the capacitor C9 are connected with the second end of the resistance R5, the second end of the capacitor C9
It is connected with the output end of the amplifier U1.
In the embodiment of the present invention, each active filter circuit 103 passes through first switch S0 and the low-pass filtering
Device is connected.
In one embodiment of the invention, the structural schematic diagram of active filter circuit 103 described in Fig. 1 such as Fig. 4
Shown, the active filter circuit 103 includes:
The first end of adjustable input resistance RX, the adjustable input resistance RX are connected with the first switch S0, it is described can
The second end of input resistance RX is adjusted to be connected with resistance R1；
The second end of the resistance R11, the resistance R11 simultaneously with the first end of the capacitor C11, inductance L1 first
End is connected；
The capacitor C11, second end ground connection；
The second end of the inductance L1, the inductance L1 are connected with the input terminal of capacitance switch sub-circuit；
The capacitance switch sub-circuit, output end are connected with the optional attenuator circuit.
As shown in figure 4, the capacitance switch sub-circuit includes:
Switch S11 and capacitor C12, the first end of the switch S11 with it is described can attenuator circuit be connected, the switch S11
Second end be connected with the first end of capacitor C12, the second end of capacitor C12 ground connection；
Switch S12 and capacitor C13, the first end of the switch S12 with it is described can attenuator circuit be connected, the switch S12
Second end be connected with the first end of capacitor C13, the second end of capacitor C13 ground connection；
Switch S13 and capacitor C14, the first end of the switch S13 with it is described can attenuator circuit be connected, the switch S13
Second end be connected with the first end of capacitor C14, the second end of capacitor C14 ground connection；
Switch S14 and capacitor C15, the first end of the switch S14 with it is described can attenuator circuit be connected, the switch S14
Second end be connected with the first end of capacitor C15, the second end of capacitor C15 ground connection；
Switch S15 and capacitor C16, the first end of the switch S15 with it is described can attenuator circuit be connected, the switch S15
Second end be connected with the first end of capacitor C16, the second end of capacitor C16 ground connection.
In one embodiment of the invention, it is contemplated that in actual detection, the size of ground resistance rate is uncertain, and
Mobility scale is very big, therefore in order to realize optimal filtering characteristic, the equivalent electricity of the filter circuit 103 always
Hold it is adjustable, specifically, equivalent needed for being calculated first according to the ground resistance rate of actual measurement and target filter cutoff frequency
Then the size of capacitor gates corresponding capacitive path by switching group, reach required equivalent capacity.
As shown in Figure 1, the detection circuit further includes two feed circuits 108, each feed circuit 108 and one group
Active filter circuit 103 is in parallel.
The feed circuit includes amplifier U3, the output end of the amplifier U3 by with a low-pass filter
Circuit 102 is connected, and constitutes closed loop switch capacitor narrow band filter.
As shown in Figure 1, the optional gain circuitry 106 includes:
Switch XX, the first end of the switch XX are connected with the differential amplifier circuit 105, the second end of the switch XX
It is connected with AC coupling circuit 1061；
AC coupling circuit 1061, the second end of the AC coupling circuit 1061 are connected with the optional gain 1062；
Switch XY, the first end of the switch XY are connected with the differential amplifier circuit 105, the second end of the switch XY
It is connected with DC coupling circuit 1063；
DC coupling circuit 1063, the second end of the DC coupling circuit 1063 are connected with the optional gain 1062；
Optional gain 1062 is connected with the A/D converter circuit 107.
In surface em signal deteching circuit provided in an embodiment of the present invention, two stage filter is provided, it can be relatively narrow
It is filtered device to noisy weak signal in frequency range, by the way that the free transmission range setting of filter is whole to lucky energy
Useful signal is covered, when passing through narrow band filter with noisy signal, bandwidth becomes smaller, so that the noise power except passband
Significantly decayed, so that the interference of noise is reduced and useful signal will not decay, so the embodiment of the present invention can be more
Accurately detect weak signal.
Although preferred embodiments of the present invention have been described, it is created once a person skilled in the art knows basic
Property concept, then additional changes and modifications may be made to these embodiments.So it includes excellent that the following claims are intended to be interpreted as
It selects embodiment and falls into all change and modification of the scope of the invention.
Obviously, various changes and modifications can be made to the invention without departing from essence of the invention by those skilled in the art
Mind and range.In this way, if these modifications and changes of the present invention belongs to the range of the claims in the present invention and its equivalent technologies
Within, then the present invention is also intended to include these modifications and variations.
Claims (10)
1. a kind of surface em signal deteching circuit characterized by comprising
Two impedance matching circuits, are connected with input interface, for input signal to be coupled into Infirmness signal detecting circuit；
Two low-pass filter circuits, each low-pass filter circuit are connected with an impedance matching circuit, for described defeated
Enter signal filtering；
Multiple active filter circuits, the multiple active filter circuit are equally divided into two groups, and each group includes multiple active
Filter circuit, each group of active filter circuit are connected with a low-pass filter circuit, each active power filtering in each group
Device circuit in parallel, the signal that the multiple active filter circuit is used to export the low-pass filter filter；
Two optional attenuator circuits, each optional attenuator circuit is connected with one group of active filter circuit, described weak for adjusting
The ground resistance of signal deteching circuit；
Differential amplifier circuit is connected with the optional attenuator circuit, for amplifying the signal of the active filter circuit output；
Two optional gain circuitries, are connected with the differential amplifier circuit, and the output for amplifying the differential amplifier circuit is believed
Number；
A/D converter circuit is connected with the optional gain circuitry, for turning the analog signal of the optional gain circuitry output
Turn to digital signal.
2. detection circuit as described in claim 1, which is characterized in that the low-pass filter circuit includes:
The first end of adjustable input resistance Rg, the adjustable input resistance Rg are connected with the impedance matching circuit, and the second of Rg
End is connected with the first end of inductance L, and the second end of the Rg is also connected with the first end of capacitor C0；
The capacitor C0, second end ground connection；
The second end of the inductance L, the inductance L are grounded by switching capacity group C1；
Amplifier U1, the reverse input end of the amplifier U1 are connected with the output end of the amplifier U1, the amplifier U1
Positive input be connected with the second end of the inductance L, active filter described in the output end of the amplifier U1 and one group
Circuit is connected；
The positive input of amplifier U2, the amplifier U2 are connected with the first end of selection sub-circuit, the amplifier U2's
Reverse input end is connected with the output end of the amplifier U2, the output end of the amplifier U2 also with the switching capacity group C1
It is connected with the connected node of capacitor C0；
The selection sub-circuit, including first choice branch R0, the second selection branch R0' and switch S8, the selection sub-circuit
Second end be connected with the output end of the amplifier U1, the positive of the first end of the switch S8 and the amplifier U2 inputs
End is connected, and the second end ground connection of the switch S8, the selection sub-circuit is used to provide different ground connection to the amplifier U2
Resistance.
3. detection circuit as claimed in claim 2, which is characterized in that the switching capacity group C1 includes:
Switch S1 and capacitor C2, the first end of the switch S1 are connected with the positive input of the amplifier U1, the switch
The second end of S1 is connected with the first end of the capacitor C2, the output end phase of the second end of the capacitor C2 and the amplifier U2
Even；
Switch S2 and capacitor C3, the first end of the switch S2 are connected with the positive input of the amplifier U1, the switch
The second end of S2 is connected with the first end of the capacitor C3, the output end phase of the second end of the capacitor C3 and the amplifier U2
Even；
Switch S3 and capacitor C4, the first end of the switch S3 are connected with the positive input of the amplifier U1, the switch
The second end of S3 is connected with the first end of the capacitor C4, the output end phase of the second end of the capacitor C4 and the amplifier U2
Even；
Switch S4 and capacitor C5, the first end of the switch S4 are connected with the positive input of the amplifier U1, the switch
The second end of S4 is connected with the first end of the capacitor C5, the output end phase of the second end of the capacitor C5 and the amplifier U2
Even；
Switch S5 and capacitor C6, the first end of the switch S5 are connected with the positive input of the amplifier U1, the switch
The second end of S5 is connected with the first end of the capacitor C6, the output end phase of the second end of the capacitor C6 and the amplifier U2
Even.
4. detection circuit as claimed in claim 2, which is characterized in that the first choice branch R0 includes:
Switch S6, the first end of the switch S6 are connected with the positive input of the amplifier U2, and the second of the switch S6
End is connected with the first end of capacitor C8；
The capacitor C8, second end ground connection；
Resistance R3, the first end of the resistance R3 are connected with the first end of the capacitor C8, the second end and electricity of the resistance R3
The first end for hindering R2 is connected；
The second end of resistance R2, the resistance R2 are grounded；
Capacitor C7, the first end of the capacitor C7 are connected with the second end of the resistance R3, the second end of the capacitor C7 and institute
The output end for stating amplifier U1 is connected；
It is described second selection branch R0' include:
Switch S7, the first end of the switch S7 are connected with the positive input of the amplifier U2, and the second of the switch S7
End is connected with the first end of capacitor C10；
The capacitor C10, second end ground connection；
Resistance R5, the first end of the resistance R5 are connected with the first end of the capacitor C10, the second end and electricity of the resistance R5
The first end for hindering R4 is connected；
The second end of resistance R4, the resistance R4 are grounded；
Capacitor C9, the first end of the capacitor C9 are connected with the second end of the resistance R5, the second end of the capacitor C9 and institute
The output end for stating amplifier U1 is connected.
5. detection circuit as claimed in claim 4, which is characterized in that each active power filtering in the multiple active filter
Device circuit is connected by first switch S0 with the low-pass filter circuit.
6. detection circuit as claimed in claim 5, which is characterized in that the active filter circuit includes:
The first end of adjustable input resistance RX, the adjustable input resistance RX are connected with the first switch S0, described adjustable defeated
The second end for entering resistance RX is connected with resistance R11；
The second end of the resistance R11, the resistance R11 are connected with the first end of the first end of capacitor C11, inductance L1 simultaneously；
The capacitor C11, second end ground connection；
The second end of the inductance L1, the inductance L1 are connected with the input terminal of capacitance switch sub-circuit；
The capacitance switch sub-circuit, output end are connected with the optional attenuator circuit.
7. detection circuit as claimed in claim 6, which is characterized in that the capacitance switch sub-circuit includes:
Switch S11 and capacitor C12, the first end of the switch S11 are connected with the optional attenuator circuit, the switch S11's
Second end is connected with the first end of capacitor C12, the second end ground connection of the capacitor C12；
Switch S12 and capacitor C13, the first end of the switch S12 are connected with the optional attenuator circuit, the switch S12's
Second end is connected with the first end of capacitor C13, the second end ground connection of the capacitor C13；
Switch S13 and capacitor C14, the first end of the switch S13 are connected with the optional attenuator circuit, the switch S13's
Second end is connected with the first end of capacitor C14, the second end ground connection of the capacitor C14；
Switch S14 and capacitor C15, the first end of the switch S14 are connected with the optional attenuator circuit, the switch S14's
Second end is connected with the first end of capacitor C15, the second end ground connection of the capacitor C15；
Switch S15 and capacitor C16, the first end of the switch S15 are connected with the optional attenuator circuit, the switch S15's
Second end is connected with the first end of capacitor C16, the second end ground connection of the capacitor C16.
8. detection circuit as described in claim 1, which is characterized in that the detection circuit further includes two feed circuits, often
A feed circuit is in parallel with one group of active filter circuit.
9. detection circuit as claimed in claim 8, which is characterized in that the feed circuit includes amplifier U3, the amplification
The output end of device U3 with a low-pass filter circuit by being connected.
10. detection circuit as described in claim 1, which is characterized in that the optional gain circuitry includes:
Switch XX, the first end of the switch XX are connected with the differential amplifier circuit, the second end and AC coupling of the switch XX
Circuit is closed to be connected；
The second end of AC coupling circuit, the AC coupling circuit is connected with optional gain；
Switch XY, the first end of the switch XY are connected with the differential amplifier circuit, the second end and DC coupling of the switch XY
Circuit is closed to be connected；
The second end of DC coupling circuit, the DC coupling circuit is connected with optional gain；
Optional gain is connected with the A/D converter circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810621668.6A CN108983297B (en) | 2018-06-15 | 2018-06-15 | A kind of surface em signal deteching circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810621668.6A CN108983297B (en) | 2018-06-15 | 2018-06-15 | A kind of surface em signal deteching circuit |
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| CN108983297B true CN108983297B (en) | 2019-07-16 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006250752A (en) * | 2005-03-11 | 2006-09-21 | Fuji Heavy Ind Ltd | Radar-type probing device |
| CN202230210U (en) * | 2011-04-29 | 2012-05-23 | 中国科学院地质与地球物理研究所 | Intelligent very low frequency electromagnetic instrument with orthogonal antenna |
| CN206193262U (en) * | 2016-11-23 | 2017-05-24 | 吉林大学 | Portable nuclear magnetic resonance noise collection system |
| CN107085241A (en) * | 2017-05-04 | 2017-08-22 | 湖南科技大学 | Underground water source detection detection means |
| CN107817531A (en) * | 2017-09-25 | 2018-03-20 | 西安电子科技大学 | Pipeline instrument receiver loop construction and signal processing method, pipeline instrument receiver |
-
2018
- 2018-06-15 CN CN201810621668.6A patent/CN108983297B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006250752A (en) * | 2005-03-11 | 2006-09-21 | Fuji Heavy Ind Ltd | Radar-type probing device |
| CN202230210U (en) * | 2011-04-29 | 2012-05-23 | 中国科学院地质与地球物理研究所 | Intelligent very low frequency electromagnetic instrument with orthogonal antenna |
| CN206193262U (en) * | 2016-11-23 | 2017-05-24 | 吉林大学 | Portable nuclear magnetic resonance noise collection system |
| CN107085241A (en) * | 2017-05-04 | 2017-08-22 | 湖南科技大学 | Underground water source detection detection means |
| CN107817531A (en) * | 2017-09-25 | 2018-03-20 | 西安电子科技大学 | Pipeline instrument receiver loop construction and signal processing method, pipeline instrument receiver |
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| CN108983297A (en) | 2018-12-11 |
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