CN1258007A - Radiation and conduction measuring system - Google Patents
Radiation and conduction measuring system Download PDFInfo
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- CN1258007A CN1258007A CN 00113713 CN00113713A CN1258007A CN 1258007 A CN1258007 A CN 1258007A CN 00113713 CN00113713 CN 00113713 CN 00113713 A CN00113713 A CN 00113713A CN 1258007 A CN1258007 A CN 1258007A
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Abstract
A system for measuring the electromagnetic radiation amount and the leakage of transmission line is composed of active magnetic field sensor, signal processing circuit, software and computer. Its advantages are high gain of sensor and system reliability, wide dynamic range, high P/C ratio, and low cost.
Description
The present invention relates to fields of measurement, a kind of specifically system that amount of electromagnetic radiation and conduction are measured.
As everyone knows, the electromagnetic radiation of electronic product is the key factor that produces environmental pollution and be detrimental to health, and the transmission line of electronic system when transmitting data owing to the leakage that radiation caused, also can have influence on the performance of product and the reliability of system.Traditional static magnetic field measurement is to utilize Hall unit as magnetic field sensor, utilizes Hall effect that magnetic field intensity is converted to voltage signal, and its defective is that it can not be measured the magnetic field of transient changing.Tradition is to use the mutual inductance principle to adopt current clamp that the exchange current in the lead is measured to the kinetic measurement of transmission line, this survey instrument is owing to adopt movable hatch frame, and magnetic core is made up of asymmetrical two parts, a needs riveted joint, the other end opening embeds measurand.Thereby, have the deficiency of three aspects, the one, purposes is single, the transient response ability, the 2nd, the slit magnetic resistance change rate is big, and gain is restricted, and the 3rd, can not measure weak current and faint radiation field.Though existing electromagnetic field measurements instrument has a variety of, be used for the NEAR FIELD SCATTERING of measurement target as scatterometer, radiometer is used for measuring the radiation field intensity and the angle distribution of antenna, also be useful on the network analyzer of microwave measurement etc., but, can only be used for dedicated frequency band and special-purpose purpose because they all are instrumentations.Along with the paces of the modernization of industry are accelerated, electronic equipment increases suddenly, has caused the deterioration of electromagnetic environment, has caused some electronic equipment cisco unity malfunction at present.Therefore pressing for a kind of convenient, flexible test macro monitors electromagnetic environment on every side, so that find equipment or part of appliance that those should not work the mischief to environment, thereby take innovative approach, make their electromagnetic exposure be reduced to the scope that environment allows, perhaps make the affected equipment adjustment of operate as normal frequency of operation around it, to guarantee operate as normal.
Purpose of the present invention is exactly that traditional measuring technology is combined with computer technology, provide a kind of can be to the transient state low-intensity magnetic field signal test system that near the faint radiation field the electronic equipment is measured and the leakage when transmitting data is measured to transmission line, finding out the strongest frequency content of radiation, thereby innovative approach is proposed.
The object of the present invention is achieved like this:
The present invention mainly includes the source magnetic field sensor, signal processing circuit and measuring system software three parts, this three part cooperates with a computing machine, constitute a transient magnetic field measuring system, it is signal of sensor entering signal treatment circuit, circuit is controlled and the signal from sensor is handled by the Survey Software that is installed in the computing machine, as shown in Figure 1.Wherein each modular construction and function are respectively:
Sensor is one " an active magnetic field sensor ", mainly forms by surveying body and amplifying circuit two parts, as shown in Figure 2.Surveying body is the sensitive element of sensor, is based on the principle of current transformer and magnetic dipole antenna and designs.Magnetic core adopts one-piece construction, socket becket in the magnetic core, becket is provided with opening part, and tested current carrying conductor passes from becket, the signal extension line that connects on the magnetic core is provided with three contacts, is connected with the low noise amplifier circuit input adapter G of three wave bands respectively; Amplifier is made as 1K-2MHz, 1.8M-12MHz, the low noise amplifier circuit of three groups of same structures of three audio range frequencies of 10M-100MHz, each group amplifying circuit comprises balancing circuitry, differential input circuit, amplifying circuit and impedance matching circuit, wherein two-way balancing circuitry A
1, A
2Input end respectively by electronic switch U
1, U
2G is connected output terminal and difference channel A with the input contact
3Input end be connected, to form single-ended output signal over the ground, this differential output signal is again by amplifier A
4With impedance inverter circuit A
5Be connected.This sensor can use separately, forms a test macro with other surveying instrument.When the measuring radiation field, the becket that can select different size for use is as receiving antenna, and the output signal that received signal is delivered to after amplifying circuit amplifies then is the output signal of whole sensor.
Signal processing circuit mainly by band selection, timing circuit, direct data channel control (DMA) circuit, gain select, A-D analog-digital conversion (ADC) circuit, memory circuit, decoding scheme, data line buffering, address wire drives and the photoelectricity coupled circuit is connected forms.
Wherein, beam selector circuit is an infrared emission circuit, be mainly used in when sensor and signal processing circuit and software unite when using to the conducting of sensor electronics switch with cut off control.Beam selector circuit adopts the coding radiation pattern, is respectively 001,010,011 with the corresponding sign indicating number of the electronic switch of three wave band amplifying circuits on the sensor, wherein most significant digit " 0 " expression low level conducting, and back two is the numbering of switch.When sensor receives one of them sign indicating number, with it Dui Ying amplifying circuit just with the connection of popping one's head in.And the emission of controlling these three sign indicating numbers is cooperated by decoding scheme, system's control bus and software three and realizes.
Timing circuit is formed connected mode such as Fig. 7 by quartz oscillator (crystal oscillator) and programmable Timer counter (counter).Crystal oscillating circuit provides 4MHz clock signal for counter circuit, and its output terminal is connected with the input end of clock of counter, and the output terminal of counter is connected with the interrupt control end INT0 of direct data channel (the following abbreviation DMA) control circuit of back.
The startup of timing circuit and stopping by software control, when first wave band (1K-2MHz) amplifying circuit of sensor is connected and during the system testing low-frequency periodic signal, by software timer conter is programmed for counting mode, dma control circuit is set to interrupt the permission mode simultaneously.
The input end of gain selection circuit is connected with the output terminal of sensor, the output terminal of gain selection circuit is connected with the input end of A-D analog-digital change-over circuit, mainly finishing to provide 64 ranges program control enlarging function, amplifies comprising 20 tunnel decay and 43 tunnel.
The A-D analog-digital change-over circuit abbreviates adc circuit as, select high-speed chip for use, inside has sampling to keep function and accurate reference voltage, the output of 8 bit digital quantity, its bandwidth of operation is consistent with sensor, the standard peripheral circuit connected mode that adopts chip manufacturing enterprise to provide.Its effect is to be the unipolarity analog signal conversion of gain selection circuit output that the memory circuit of delivering to the back behind the digital quantity is temporarily preserved, and its working control signal is provided by the control bus of address decoding circuitry and computer system.
Memory circuit is mainly in order to improve the dynamic response capability of whole test system, the least possiblely takies the hardware resource of computer system and designs.It has two directly effects: (1) gives full play to the high speed performance of previous stage ADC, and the data after ADC changes are in time preserved.(2) make system have on-line testing and two kinds of functions of off-line test.The on-line testing function embodiment after the data rapid saving, complete showing test results on computer screen.The off-line test function embodiment is after end of test (EOT), and data still are retained in the storer, as long as system does not cut off the power supply, can at any time these data be shown on screen as required or dump in the hard disk of computing machine.Circuit provides the storage unit of 8M byte (byte), and when writing data, its address is by the dma control circuit management that is connected with it.When data were sent to computing machine, its address was by the address bus management of computer system.
Direct data channel control (DMA) circuit is by programmable interrupt controller U
3With programmable counter U
4Form, finish that mainly memory circuit is managed.
Address decoding circuitry is the necessary circuit of computer system management external circuit, its input end is connected with the address bus of computer system, to be exactly " address code " of distributing to top each circuit be connected with top related circuit control end output terminal, is convenient to by software these circuit be controlled.
The data bus buffer circuit uses the bidirectional bus transceiver, and an end is connected with the memory data line, and the other end is connected with the data bus of computer system by the photoelectricity coupled circuit.Its effect is that the data line to foregoing circuit drives, and guarantees the reliable of data transmission.
The address bus driving circuit adopts the unidirectional logic gates of high speed, and its input end is connected with the address bus of computer system by the photoelectricity coupled circuit, and output terminal is connected with MUX in memory circuit, decoding scheme and the gain selection circuit.
For the minimum that influences each other between the circuit that makes foregoing circuit and computer system, the circuit that they are connected with computer system all adopts the photoelectricity coupled circuit to carry out isolation processing.
Survey Software of the present invention is made up of control program and routine analyzer two parts.The effect of control program is that the course of work of whole signal processing circuit is controlled.Comprise band selection, start timing circuit, start mould/number conversion circuit, to timing circuit and dma circuit initialization, show that time domain and frequency-domain waveform, preservation data file and control prints etc.The effect of routine analyzer is that the data of gathering are analyzed, as at first the background test result being analyzed, and the display analysis result.If surpass certain limit, then show the amount that surpasses, prompting operation person places rational environment with measurand, as by National Standard GB3907-83 " regulation carry out.Next is that the time-domain signal of measuring is carried out Fourier transform (FFT), converts frequency-region signal to and shows.The whole operation process is finished under the Windows interface by operational computations switch dish.
Whole Survey Software can also be set to " backstage executive mode " under Windows 95 operating systems, carry out " day radiation average monitoring ".The operator carries out other work on the foreground.
The present invention compares with same category of device, has following characteristics and effect:
1. gain height, the good reliability of sensor are good at design frequency band internal linear response performance, are fit to measure weak field signal such as the radiation of electronic equipment and the leakage of data line.Test result as shown in figure 14.
2. system is easy to use, flexible.Native system is adapted at the occasion use that electronic equipment is concentrated, and this occasion generally has computing machine certainly.The signal processing circuit of test macro is pressed the standard computer interface circuit design, as long as it is inserted on the expansion slot of any microcomputer, software is installed under the Windows operating system, just can monitor environment.Can also test Electromagnetic Compatibility of Power Electronics (EMC).
3. simple in structure, be convenient to make.From the composition of system, structure is very simple.The sensor probe of native system is a whole magnetic core structure, is convenient to processing, and amplifying circuit and signal processing circuit adopt the nondedicated part design, is convenient to produce.Be used with computing machine, just form an intelligent test system.The test result of sensor detection body as shown in figure 13.
4. wide dynamic range, ratio of performance to price height.Compare with similar computer product, finished product data collecting card general work speed on the market is medium, and the signal frequency range of adaptation is below 2MHz, and the signal frequency that native system is handled reaches 100MHz, because of adopting the mainstream chip design on the market, the price of the two is suitable.From the computing machine angle, this test macro is equivalent to an expansion external unit, has promptly increased the function in a test magnetic field to computing machine.Therefore, it is a high-performance, low-cost device.Its ratio of performance to price is tens of times of specialized equipment.
5. after stopping to measure, the original function of computing machine is not affected, and other instrumentation has only the function that has the deviser in use and given, and after stopping to measure, only is an instrument.
Below be drawings and Examples of the present invention.
Fig. 1 is the block diagram of system of the present invention
Fig. 2 is that sensor of the present invention is formed block scheme
Fig. 3 is the detection body structure figure in the sensor of the present invention
Fig. 4 is the amplifying circuit schematic diagram in the sensor of the present invention
Fig. 5 is that signal processing circuit of the present invention constitutes block scheme
Fig. 6 is that signal processing circuit medium wave band of the present invention is selected circuit power valve installation site figure
Fig. 7 is that the timing circuit in the signal processing circuit is formed block scheme
Fig. 8 is the data acquisition principle schematic of timing circuit low-frequency periodic signal of the present invention
Fig. 9 is that the direct data channel control circuit in the signal processing circuit of the present invention is formed block scheme
Figure 10 is a Survey Software process flow diagram of the present invention
Figure 11 is a Survey Software surface chart of the present invention
Figure 12 is a detection body examination examination equivalent circuit diagram of the present invention
Figure 13 is to surveying the amplitude versus frequency characte figure of body examination examination
Figure 14, the 15th, the amplitude versus frequency characte figure of sensor of the present invention
Figure 16 is example test result figure of the present invention
Among Fig. 1, computing machine is a micro-personal computer system, requires the CPU frequency should be greater than 200MHz, otherwise can not realize the repertoire of this test macro, and Windows 95 or windows NT operating system also will be housed.Signal processing circuit and Survey Software close fit, they form the field signal measuring system jointly.
Among Fig. 2, survey the sensitive element of body as sensor, the principle design that it is based on current transformer and magnetic dipole antenna forms.When transmission line is measured, use the mutual inductance principle, the little ring of metal of process opening places current carrying conductor in the becket grade coupled with magnetic ring coil two, and when the measuring radiation field, the becket that can select different size for use is as receiving antenna.Amplifying circuit is made as 1K-2MHz, 1.8M-2MHz, three wave bands of 10M-100MHz.The signal of detection body output is delivered to amplifying circuit and is amplified, and the output signal of amplifying circuit is exactly the output signal of whole sensor.
The structure of detection body shown in Figure 3, comprise integral ring-shaped magnetic core coil 1 and with becket 2 two parts of coil socket.When transmission line is measured, an opening 3 is arranged on the becket, tested lead 4 is embedded little ring by opening.A signal extension line 5 is arranged on the magnetic core coil.The job operation of magnet ring and magnetic core coil is identical with the job operation of toroidal transformer and technology, and becket adopts bare copper wire or silver-coated copper wire to process.The becket that is used for conduction measurement needs the opening overlap joint, and opening part is carried out Alloying Treatment and Quenching Treatment, makes it enough elasticity be arranged with after guaranteeing to embed tested insulated conductor, and two joints can contact closely, make contact resistance enough little.Be used for radiometric becket and be welded into integral body.
Sensor amplifying circuit shown in Figure 4, its principle is that an amplitude of the voltage signal that coupling is come through magnetic ring coil is amplified to enough greatly, make subsequent conditioning circuit under normal condition, just can handle, perhaps just be connected and measure with the conventionally test instrument.It is made up of the amplifying circuit of three frequencies (ripple) sections, and the amplification circuit structure of three wave bands is identical, and the operational amplifier of selecting for use is also identical, only is different with the value of the resistance of operational amplifier connection and electric capacity, and Fig. 4 is the schematic diagram of a wave band.G is the input end of probe signal among the figure, and A1, A2 and the resistance capacitance Compositional balance circuit around them, A3 adopt the differential type input, can suppress the common mode interference of circuit itself effectively, exports a unipolar signal over the ground.A4 further amplifies the signal of A3 output, and A5 is an impedance inverter circuit, and it transforms to the output resistance of amplifying circuit and 50 ohm load matched.The electronic switch of input amplifier is a Photoelectric infrared switch.When sensor independently used, the electronic switch controling end above it made its conducting by manual wire jumper ground connection, perhaps with the conducting respectively of three electronic switches of Infrared remote controller control.When sensor and signal processing circuit were used, it was controlled jointly by beam selector circuit above the signal processing circuit and software.In order to overcome the noise of amplifier circuit itself, except selecting the low noise element for use, shorten interelement line as far as possible.When making, 1K-2MHz, 1.8M-12MHz the circuit component of two wave bands is placed in the one side of printed circuit board (PCB), and the circuit component of 10M-100MHz wave band is placed in the another side of printed circuit board (PCB), for preventing other circuit of secondary radiation interference, whole elements of high frequency band are shielded with metal shell.
Signal processing circuit shown in Figure 5, comprise that band selection, timing circuit, direct data channel control (DMA), gain selection, A-D analog-digital are changed (ADC), memory circuit, decoding scheme, data line buffering, address wire drives and photoelectricity coupling 10 big parts, pass through multiply or single cord connection between each parts.The input and output direction of arrow points representation signal among the figure, two-wire is represented the multiply line, and single line is represented the sub-thread line.DB, AB and CB represent data bus, address bus and the control bus of computer system respectively.IN is and the tie point of sensor output terminal that Em represents the control signal that the infraluminescence pipe sends in the beam selector circuit.The convenience of operation when consider measuring is installed in the back of computer host box with the infrared transmitting tube of beam selector circuit, is positioned at the top of sensor incoming line jack.Position as 6 indications among Fig. 6.7 is sensor incoming line jack among Fig. 6, and 8 is computer main frame panel, and 9 is signal processing circuit, and 10 is the computer host box shell.
Timing circuit shown in Figure 7 comprises crystal oscillating circuit and timer conter, and the clock signal of exporting from crystal oscillating circuit enters timer conter, and the output terminal of counter is connected with the interrupt control end of dma control circuit.In order to prevent that system takies storage space with regard to collecting too much data in less than a signal period, use the time interval proper extension of timing circuit with image data, its principle is as shown in Figure 8.Transverse axis among Fig. 8 is represented the time, the amplitude of vertical axis represent signal.Clock signal is provided by crystal oscillating circuit, every n
1The individual clock period, counter sends a look-at-me, and dma controller is accepted look-at-me, makes storer deposit data in.If in a signal period, preserved n altogether
2Individual data, then the frequency of signal is f=l/ (n
1n
2Δ t), wherein Δ t is a clock period.As can be seen from Figure 8, n
1=4, n
2=4.A triangle equals 16 clock period wave period among the figure, obtains 4 sampled values in each signal period, has both satisfied the requirement of sampling thheorem, makes sampled data be unlikely to too much again.Adopt this method can make this signal processing circuit operating frequency range wideer, even do not use the magnetic field sensor of introducing previously, this circuit can also be used to handle low frequency and high-frequency signal as a general data acquisition circuit.Timing circuit is opened as required or is stopped, and when measuring random signal, does not need timing circuit work, and available software is selected timer conter clear 0, and it is quit work.And the INT0 that is provided with in the dma control circuit is the interrupt inhibit mode.
The dma circuit that shown in Figure 9 is in the signal processing circuit, it is by programmable interrupt controller U
2With programmable counter U
4Form, be responsible for memory circuit is managed.DB and AB represent the data bus and the address bus of computer system respectively.When starting this test macro, to interrupting controller programming, and the counter initial value is changed to the address of first unit of storer by software.A among the figure is connected with the output terminal of timing circuit, the interrupt request that timing circuit sends is accepted in its interruption 0 (INT0), B among the figure is connected with the EOC signal output part of analog/digital conversion (ADC) circuit, interrupts the EOC signal that 1 (INT1) accepts adc circuit.When response interrupts 0, will interrupt 1 and open, counter adds 1, after memory circuit reads data, will interrupt 1 and close.Promptly have only when interruption 0 meets with a response, could respond and once interrupt 1, interruption 1 after this all can not be responded.This point and Fig. 8 are closely related, and sampled signal although the work of adc circuit does not pause, is not that each data is all deposited in the storer by output (INT0) control of timing circuit.When timing circuit quits work, interrupt 1 and open forever, can both meet with a response, i.e. at every turn each data of adc circuit collection can both be stored circuit and preserve.C among the figure comes from the logical combination that the computer system control bus " is read " control signal and address decoding circuitry output, interrupts 2 (INT2) and accepts the control signal that computer system is sent.When response interrupts 2, make counter get back to initial value.Have only when computer system and during reading of data, just send interrupt request to dma circuit from top memory circuit, after meeting with a response, the address of memory circuit is by computer system management.The dma circuit and the interrupt management of this point and computer system are different.
Survey Software flow process shown in Figure 10 is carried out as follows:
1. beginning
After carrying out Survey Software, start whole signal processing circuit.At first, be set at counting mode, the corresponding sampling interval n of counting initial value to the timing circuit programming
1, alternative data of prompting and corresponding sampling interval (time) are selected input as required on screen, if do not import, then point out timer to quit work.Secondly to the dma circuit programming, write control word to interruptable controller, write the counting initial value to address counter, this initial value is corresponding with the address of first storage unit of memory circuit.To gain at last and elect " 1 " as.
2. background verification
Probe power is opened in prompting, and after obtaining answering " Y ", software is connected three amplifying circuits on the sensor automatically in turn, successively test data is preserved.
3. demonstration check results
Screen is divided into three zones, upper, middle and lower, the signal of three wave bands of sensor is shown on screen simultaneously.In program internal condition Design of Sensor parameter measured signal is converted to corresponding magnetic field intensity, therefore, what provide on the screen is the function corresponding relation of magnetic field intensity and time.Prompting simultaneously wants to show frequency spectrum, if need then show frequency spectrum.No matter whether show frequency spectrum, next will point out test whether to continue, as answering " N ", end of test then, software returns to operating system.As answering " Y ", then above-mentioned test result is deposited with document form, and carry out next step.
4. Frequency Band Selection
Measurand is ready to,, selects the frequency range that needs according to software prompt.If select first frequency range, also fixed time interval is selected in prompting.When measurand is not a periodic signal, can not select fixed time interval.
5. image data
The software startup adc circuit, each wave band gathers 2
20Stop after the individual data of=1048576 (being 1Mbyte).These data are temporarily stored in the memory circuit of signal processing circuit.
6. demonstration time domain waveform
After the data of gathering above being converted to the magnetic field value of correspondence, on screen, show, make us can observe the size of signal amplitude.Generally speaking, waveform is a continually varying, if amplitude is too big, will straight line occur in the lower edge on screen, and should gain this moment according to the prompting adjustment on the screen.Notice that the figure on the screen indicates decay and amplifies both direction, if straight line appears in last lower edge, should be to the adjustment of decay direction.If signal amplitude is too little, concentrate near screen center's horizontal line, then should be to amplifying the direction adjustment.This process generally need repeat several times, as using General Instrument.Only here, being operation keyboard and Genius mouse, is manual knob and use General Instrument.The action that adjustment gains on screen and the action of gain selection circuit are closely related, to which direction adjust on the screen, under the control of software, just have corresponding " switch " to be switched in the gain selection circuit.This technology is the key point of software and combination of hardware.The amplitude of signal is carried out next step after adjusting to " satisfaction ".
7. Fourier transform
The fast algorithm of software application Fourier transform (FFT) is handled above-mentioned data, obtains the relation of amplitude and frequency.This is the most frequently used means of spectrum analysis.
8. demonstration frequency-domain waveform
Whether needs show frequency-domain waveform according to screen prompt, as answering " Y ", then show, answer " N ", then do not show.
In sum, 2 and 3 are actually and have automatically performed 4,5,6,7 and 8 five steps, do not have manual intervention substantially.And, operate this test macro as the operation General Instrument since the 4th step.
The interface of this software as shown in figure 11.5/6ths zones, screen left side are used for display waveform.Right side sixth zone design becomes a panel board, has timing circuit, DMA counter, band selection, gain to select, show icons such as time domain waveform, demonstration frequency-domain waveform from top to bottom successively.In the below of this " panel board ", also leave a wicket, operate accordingly with Chinese prompt.Delegation's prompting is arranged in the bottom of screen, illustrate that what content the curve that shows on the current screen is.Be meant the amplitude versus frequency characte of sensor as " sensor response ".If point out " time domain response " or " frequency domain response ", then give the wave band of sensor on the left side of this delegation.
Figure 12 and Figure 13 are fail-safe analysis of the present invention and test.Figure 12 surveys the body equivalent electrical circuit, wherein L1, L2 and L3 are respectively the equivalent inductance of becket, magnetic core coil, R1, R2 and R3 are respectively the equivalent resistance of becket, magnetic core coil, and R4 is output impedance, and C1 and C2 are the coupling capacitance of becket and magnetic core coil.The signal that V=F (H) receives for becket by the signal generator emission.The circuit parameter of Figure 12 is input in the PSPICE circuit analysis software, this circuit is simulated, the gained result is shown in the dotted line among Figure 13 (I).The probe that obtains with the test of BT-3B sweep generator gains---and frequency response curve (amplitude versus frequency characte) is shown in the solid line among Figure 13 (II).The longitudinal axis among Figure 13 is the gain (enlargement factor) of probe, and unit is a decibel, by expression formula Ah (dB)=20log (H/H
0) definition, the enlargement factor of representing to pop one's head in of the Ah in the formula to magnetic field strength component in the measuring-signal, log is a denary logarithm, H and H
0It is respectively the value of magnetic field intensity in output and the input signal.Transverse axis is represented frequency, and unit is Hz.The power of numeral 10 below the transverse axis represents 10 as " 2 "
2=100Hz, " 3 " represent 10
3=1000Hz=1KHz ... " 8 " then represent 10
8=100MHz.Sweep generator finishes to 100MHz from 100Hz, marks with English under figure.Result from Figure 13 as can be seen, the gain of probe is 25dB, and the frequency response in magnetic field is had good linear relationship, low-frequency cut-off frequency is less than 1KHz.When frequency during greater than 1KHz, the variation of gain is very little, less than 0.2dB.Between 1KHz and 100MHz, computer simulation and measured result coincide.
Figure 14 combines Figure 12 and Fig. 4, and the input of the parameter among two figure PSPICE circuit analysis software, the frequency response results of simulation is shown in the dotted line among Figure 14 (III), and the frequency response results that records with HP8028A signal source and HP3577A analyser is shown in the solid line among Figure 14 (IV).The longitudinal axis among Figure 14 is the gain (enlargement factor) of sensor, and unit is a decibel, by expression formula Ah (dB)=20log (H/H
0) definition, the Ah in the formula represents the enlargement factor of sensor to magnetic field strength component in the measuring-signal, log is a denary logarithm, H and H
0It is respectively the value of magnetic field intensity in output and the input signal.Transverse axis is represented frequency, and unit is Hz.Here it should be noted that the power of numeral 10 below the transverse axis, represent 10 as " 2 "
2=100Hz, " 3 " represent 10
3=1000Hz=1KHz ... " 8 " then represent 10
8=100MHz.Sweep generator finishes to 100MHz from 100Hz, marks with English under figure.Result from Figure 14 as can be seen, the gain of sensor is 65dB, and the frequency response in magnetic field is had good linear relationship, low-frequency cut-off frequency is 1KHz.When frequency during greater than 1KHz, the variation of gain is less than 3dB.Between 1KHz and 100MHz, computer simulation and measured result are identical substantially.
Need to prove for computer simulation results contrast, the amplitude-frequency response of three wave bands of sensor is divided according to the frequency range of amplifying circuit and is connected.The amplitude versus frequency characte of three wave bands such as Figure 15.Coordinate among Figure 15 and the represented implication of numeral are identical with Figure 13, Figure 14, solid line (C), dotted line (D) and dotted line (E) respectively with wave band 1K-2MHz, wave band 1.8M-12MHz, the measurement result correspondence of wave band 10M-100MHz.
Embodiment
Certain equipment is measured according to the connected mode of Fig. 1 with this measuring system, under the same conditions, with HP3577A same equipment is also measured, Figure 16 provides the contrast of measurement result.Give among the figure with above-mentioned two cover measuring systems the measurement of this radiation of equipment electric field, confirmed that sensor compares the response weak effect in magnetic field really to the response of electric field.Horizontal ordinate among Figure 16 is represented frequency, and is identical with the implication of Figure 15.Ordinate is represented electric field and magnetic field amplitude simultaneously, and maximal value is-50, and minimum value is-130.When representing magnetic field, with formula 20log (H/H
0) definition, H here
0Get 1 amperes per meter (A/m), H represents measured value.When ordinate is represented electric field, with formula 20log (E/E
0) definition, E here
0Get 1 volts/meter (V/m), E represents measured value.Solid line among Figure 16 is the result who measures with the present invention's (being system shown in Figure 1), dotted line is the result who measures with HP3577A, (f) solid line of indication and dotted line are the field strength values that records, (g) solid line of indication and dotted line are the electric field intensity values that records, that (h) provide is the maximal value-55dB (A/m) of magnetic field intensity, i.e. 1.8 milliamperes/meter (mA/m).That (i) provide is the maximal value-80dB (V/m) of electric field intensity, i.e. 0.1 millivolt/meter (mV/m).The relative value of the magnetic field intensity that systematic survey obtains is than the big 20dB of relative value of resulting electric field intensity, and when frequency during greater than 100KHz, it is big that this difference is also wanted.Therefore as can be seen, core of the present invention---sensor is really to many to the response sensitivity of electric field of the response ratio in magnetic field.
Employed integrated package model is as follows respectively in the circuit theory diagrams of the present invention:
A1：MAX4162 U3：Intel8259A
A2：MAX4162 U4：Intel8253A
A3：MAX4199
A4：MAX4329
A2：MAX4329
Claims (7)
1. radiation and conduction measuring system, comprise sensor, signal processing circuit and Survey Software, signal of sensor entering signal treatment circuit, and under the control of Survey Software, the radiation of electronic equipment and the leakage of transmission line are measured, it is characterized in that:
A. sensor is an active magnetic field sensor that is made of detection body and amplifying circuit, magnetic core (1) adopts one-piece construction, the interior socket becket of magnetic core (1) (2), becket (2) is provided with opening part (3), tested current carrying conductor (4) passes from becket (2), magnetic core (1) is gone up the signal extension line that connects and is provided with three contacts, be connected with the low noise amplifier circuit input adapter G of three wave bands respectively, amplifier is made as 1K-2MHz, 1.8M-12MHz, the low noise amplifier circuit of three groups of same structures of three audio range frequencies of 10M-100MHz, each group amplifying circuit comprises balancing circuitry, differential input circuit, amplifying circuit and impedance matching circuit, wherein two-way balancing circuitry A
1, A
2Input end respectively by electronic switch U
1, U
2G is connected output terminal and difference channel A with the input contact
3Input end be connected, to form single-ended output signal over the ground, this differential output signal is again by amplifier A
4With impedance inverter circuit A
5Be connected;
B. signal processing circuit mainly is connected with the photoelectricity coupled circuit and is formed by band selection, timing circuit, direct data channel control, gain selection, A-D analog-digital conversion, memory circuit, decoding scheme, data line buffering, address driving, wherein:
Beam selector circuit is an infrared emission circuit, adopts the coding radiation pattern, with three ripples on the sensor
The electronic switch of the amplifying circuit of section is corresponding, is respectively 001,010,011;
Timing circuit is made of quartz oscillator and programmable Timer counter, the output terminal of crystal oscillating circuit with
The input end of clock of counter connects, and for counter provides clock signal, the output terminal of counter is with direct
The interrupt control end INT0 of data channel control circuit connects, and counter is programmed for counting by Survey Software
Mode, and when starting timing circuit, the direct data channel control circuit is set at the permission mode of interrupting;
The input end of gain selection circuit is connected with the output terminal of sensor, output terminal and A-D analog-digital conversion
The input end on road connects, and mainly finishes 64 distance controls and amplifies and decay;
The A-D analog-digital change-over circuit is selected the bandwidth of operation identical with sensor for use, mainly finishes gain is selected
The unipolarity analog signal conversion of road output is that digital quantity outputs to memory circuit, and by address decoding circuitry and
Computer-control bus provides working control signal;
C. Survey Software comprises control program and routine analyzer two parts, control program is mainly finished the course of work of entire circuit is controlled, comprise to timing circuit and the initialization of direct data channel control circuit, band selection, startup timing circuit, start the A-D analog-digital change-over circuit, show that time domain and frequency-domain waveform, preservation data file and control prints that routine analyzer is mainly finished the data of gathering are analyzed, the time-domain signal of measuring is carried out Fourier transform converted frequency-region signal to and show.
2. measuring system according to claim 1, it is characterized in that when transmission line is measured, the becket (2) of surveying body adopts the opening bridging arrangement, and insert in the becket current carrying conductor (4) grade coupled with magnetic core coil two through this opening part (3), when the detection body is used for the measuring radiation field, becket (2) adopts and to be welded into whole structure, and the becket that can select different size for use is as receiving antenna.
3. measuring system according to claim 1 is characterized in that the electronic switch U that the input amplifier of sensor connects
1And U
2Adopt Photoelectric infrared switch, when sensor independently used, electronic switch controling end made its conducting by manual wire jumper ground connection, or controlled the conducting respectively of triband electronic switch with Infrared remote controller; When sensor and signal processing circuit are used, control jointly by beam selector circuit and Survey Software.
4. measuring system according to claim 1 is characterized in that the infrared transmitting tube of beam selector circuit is installed in the back of computer host box, is positioned at the top of sensor incoming line jack.
5. measuring system according to claim 1 is characterized in that providing clock signal by crystal oscillating circuit in the timing circuit, and counter is every n
1The individual clock period, send a look-at-me, the direct data channel circuit is accepted look-at-me, makes storer deposit data in.
6. measuring system according to claim 1 is characterized in that the direct data channel control circuit is by programmable interrupt controller U
3With programmable counter U
4Form U
3A end be connected U with the output terminal of timing circuit
3Interrupt INT 0 accept the interrupt request that timing circuit sends, U
3B end be connected with the EOC signal output part of A-D analog-digital change-over circuit, interrupt INT 1 is accepted the EOC signal of A-D analog-digital change-over circuit.
7. measuring system according to claim 1 is characterized in that Survey Software undertaken by following flow process:
1. begin
After carrying out Survey Software, start whole signal processing circuit, at first, be set at counting mode, the corresponding sampling interval n of counting initial value the timing circuit programming
1Alternative data of prompting and corresponding sampling interval (time) are selected input as required on screen, if do not import, then point out timer to quit work, secondly to the dma circuit programming, write control word, write the counting initial value to address counter to interruptable controller, this initial value is corresponding with the address of first storage unit of memory circuit, will gain at last and select to be made as " 1 ";
2. background verification
Probe power is opened in prompting, and after obtaining answering " Y ", software is connected three amplifying circuits on the sensor automatically in turn, successively test data is preserved;
3. show check results
Screen is divided into three zones, upper, middle and lower, the signal of three wave bands of sensor is shown on screen simultaneously, in program internal condition Design of Sensor parameter measured signal is converted to corresponding magnetic field intensity, what provide on the screen is the function corresponding relation of magnetic field intensity and time, prompting simultaneously wants to show frequency spectrum, if need then show frequency spectrum;
4. Frequency Band Selection
Measurand is ready to, and according to software prompt, the frequency range that selection needs if select first frequency range, is also pointed out the selection fixed time interval;
5. image data
The software startup adc circuit, each wave band gathers 2
20Stop after the individual data of=1048576 (being 1Mbyte), these data are temporarily stored in the memory circuit of signal processing circuit;
6. show time domain waveform
After the data of gathering above being converted to the magnetic field value of correspondence, on screen, show, adjust gain selection circuit according to the signal amplitude size;
7. Fourier transform
The fast algorithm of software application Fourier transform (FFT) is handled above-mentioned data, obtains the relation of amplitude and frequency;
8. show frequency-domain waveform
According to screen prompt, show frequency-domain waveform on demand.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001137131A CN1142441C (en) | 2000-01-19 | 2000-01-19 | Radiation and conduction measuring system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001137131A CN1142441C (en) | 2000-01-19 | 2000-01-19 | Radiation and conduction measuring system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1258007A true CN1258007A (en) | 2000-06-28 |
| CN1142441C CN1142441C (en) | 2004-03-17 |
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ID=4583473
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001137131A Expired - Fee Related CN1142441C (en) | 2000-01-19 | 2000-01-19 | Radiation and conduction measuring system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1142441C (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100360946C (en) * | 2002-05-17 | 2008-01-09 | 松下电器产业株式会社 | Apparatus for and method of measuring local specific absorption range SAR |
| CN101126615B (en) * | 2007-09-04 | 2010-06-02 | 中国人民解放军理工大学工程兵工程学院 | Bullet shooting counter |
| CN101813756A (en) * | 2010-04-23 | 2010-08-25 | 华北电力大学 | Method for manufacturing transient high-frequency magnetic field of power system |
| CN101859119A (en) * | 2010-07-02 | 2010-10-13 | 北京联合大学生物化学工程学院 | Display instrument with controllable amplifier gain |
| CN102103014A (en) * | 2010-12-13 | 2011-06-22 | 苏州大学 | Detecting method for periodic transient component in signal |
| CN108267647A (en) * | 2017-12-19 | 2018-07-10 | 中国电子科技网络信息安全有限公司 | A kind of detection method and device of power supply conduction electromagnetic leakage protection |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100360946C (en) * | 2002-05-17 | 2008-01-09 | 松下电器产业株式会社 | Apparatus for and method of measuring local specific absorption range SAR |
| CN101126615B (en) * | 2007-09-04 | 2010-06-02 | 中国人民解放军理工大学工程兵工程学院 | Bullet shooting counter |
| CN101813756A (en) * | 2010-04-23 | 2010-08-25 | 华北电力大学 | Method for manufacturing transient high-frequency magnetic field of power system |
| CN101859119A (en) * | 2010-07-02 | 2010-10-13 | 北京联合大学生物化学工程学院 | Display instrument with controllable amplifier gain |
| CN101859119B (en) * | 2010-07-02 | 2012-03-21 | 北京联合大学生物化学工程学院 | Display instrument with controllable amplifier gain |
| CN102103014A (en) * | 2010-12-13 | 2011-06-22 | 苏州大学 | Detecting method for periodic transient component in signal |
| CN102103014B (en) * | 2010-12-13 | 2012-09-05 | 苏州大学 | Detecting method for periodic transient component in signal |
| CN108267647A (en) * | 2017-12-19 | 2018-07-10 | 中国电子科技网络信息安全有限公司 | A kind of detection method and device of power supply conduction electromagnetic leakage protection |
| CN108572034A (en) * | 2018-04-24 | 2018-09-25 | 电子科技大学 | A kind of temperature sensor circuit of embedded clock |
| CN110688652A (en) * | 2019-08-30 | 2020-01-14 | 中国电子科技网络信息安全有限公司 | USB micro electromagnetic leakage signal source |
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