CN101251606A - Interference suppression circuit for industrial frequency harmonic of desired signal in frequency band of weak signal detection apparatus - Google Patents
Interference suppression circuit for industrial frequency harmonic of desired signal in frequency band of weak signal detection apparatus Download PDFInfo
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- CN101251606A CN101251606A CNA200810050580XA CN200810050580A CN101251606A CN 101251606 A CN101251606 A CN 101251606A CN A200810050580X A CNA200810050580X A CN A200810050580XA CN 200810050580 A CN200810050580 A CN 200810050580A CN 101251606 A CN101251606 A CN 101251606A
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Abstract
The invention discloses a circuit of suppressing power frequency harmonic interference in a useful signal band in a weak signal detection apparatus which is a compensation circuit by completely tracking the interference caused by the frequency harmonic in the useful signal band through frequency, phase and amplitude. The circuit is connected and disconnected between a main microprocessor signal controlling sensor and an impedance matching network, wherein the impedance matching network is connected with a program-controlled amplifier via a preamplifier and a broad band filter, an output signal envelope detector is connected with a slave microprocessor through a control line and a data bus, the program-control amplifier is connected with a DDS signal generator via a phase lock loop. The circuit of suppressing frequency harmonic interference in a useful signal band in a weak signal detection apparatus can suppress the interference of frequency harmonic in a useful signal band in a weak signal detection apparatus effectively, track the frequency, phase and amplitude in a real-time of the interference and filter the interference from the received signals without any influence on the other useful signals and useful frequency elements overlapping with the interference signals.
Description
Technical field
The present invention relates to the reception amplification filtering part of detecting instrument, is to utilize frequency, phase place, the comprehensive tracking technique of amplitude, and industrial frequency harmonic causes the circuit of interference in the compensation useful signal frequency band.
Background technology
In the Testing of Feeble Signals instrument, need to improve signal to noise ratio (S/N ratio).The effective means that improves signal to noise ratio (S/N ratio) is with noise and interference beyond the narrow as far as possible bandpass filter filtering useful signal frequency band.But just in time just in the useful signal frequency band, the amplitude of this undesired signal, frequency and phase place change not quite at short notice in the interference that has.Because trapper has certain resistance band, if, can lose a part of useful signal frequency content with common trapper or this interference of tracking trapper filtering.So just need a kind of circuit of invention, this interference under the prerequisite of losing the useful signal frequency content hardly in the filtering useful signal frequency band.For example in the nuclear magnetic resonance water witch, a kind of interference that comes to this of industrial frequency harmonic, especially odd harmonic.
Utilizing nuclear magnetic resonance principle to seek underground water is a kind of new technology that development in recent years is got up.It has unique solution, speed is fast and cost is low characteristics, lies prostrate hundreds of volt magnitudes of receiving but its signal has only number to receive, and very easily is subjected to the surrounding environment disturbing effect and makes the result fuzzy even can't work.The signal frequency of nuclear magnetic resonance water witch is the Larmor frequency that is directly proportional with the terrestrial magnetic field, and it is 1.278KHz～2.556KHz in the world.Interference beyond this frequency range can add the broadband filter filtering of big steepness with tight shielding measure.For filtering interfering more up hill and dale, nuclear magnetic resonance water witch amplifier centre frequency is the measured point Larmor frequency, and bandwidth is 100Hz, the further filtering of the program-controlled wave filter of centre frequency.But always having at least one power frequency odd harmonic frequencies interference drops in this frequency band.Sometimes this industrial frequency harmonic interference magnitude is more much bigger than useful signal amplitude.Because the work frequency maximum possible has 1% frequency drift, so this disturbs the frequency drift that 26Hz may maximum be arranged, it is uncertain with the phase differential of useful signal, and its amplitude also is uncertain, so can not use the trapper filtering of fixed frequency.Because of trapper certain resistance band is arranged again, thus the program-controlled trapper filtering of centre frequency can not be used, otherwise can cause very big distorted signals.
The invention provides a kind of new circuit, can follow the tracks of frequency, phase place and the amplitude of this interference in real time,, and do not influence other useful signal, not even influence and the overlapping useful signal frequency content of this interfering frequency its filtering from received signal.
Other are every to have the detecting instrument that this useful signal frequency band contains the interference that industrial frequency harmonic causes, and all available sort circuit suppresses this interference.Be not only the interference that industrial frequency harmonic causes in fact, the electric signal that every frequency, phase place, amplitude only changed in a very little scope in the short time disturbs also all available sort circuit to suppress.
Summary of the invention
Purpose of the present invention just is at above-mentioned the deficiencies in the prior art, provide a kind of and suppress the interference of the industrial frequency harmonic in the useful signal frequency band in the detecting instrument effectively, and avoid this inhibition interfering process as much as possible industrial frequency harmonic codan in the useful signal frequency band in the Testing of Feeble Signals instrument of useful signal weakening.
The objective of the invention is to realize in the following manner:
Beneficial effect: the present invention has suppressed the interference of the industrial frequency harmonic in the useful signal frequency band in the detecting instrument effectively, can follow the tracks of frequency, phase place and the amplitude of this interference in real time, with its filtering from received signal, and do not influence other useful signal, even do not influence and the overlapping useful signal frequency content of this interfering frequency.
Description of drawings
Accompanying drawing is: industrial frequency harmonic codan block diagram in the useful signal frequency band in the Testing of Feeble Signals instrument.
1 master microprocessor, 2,4,6,14,16,17,20 control lines, 3 from microprocessor, 5 program control narrow band filters, 7DDS signal generator, 8 subtracters, 9 signal transducers, 10 prime amplifiers, 11 programmable amplifiers, 12 phaselocked loops, 13 output signal envelope detecting devices, 15,23 data buss, 18 impedance matching networks, 19 broadband filters, 21 power capacitor charging control circuits, 22 transmitters
Embodiment
Be described in further detail below in conjunction with drawings and Examples:
Detecting instrument master microprocessor 1 is given from microprocessor 3 by control line 2 and is sent the order of following the tracks of industrial frequency harmonic interference in the useful signal frequency band, calculate the useful signal frequency from microprocessor 3, set the centre frequency of program control narrow band filter 5 by control line 4, to set DDS signal generators 7 initial output amplitudes be zero and it is added to the cut signal input end of subtracter 8 by control line 6.Industrial frequency harmonic undesired signal in the useful signal frequency band that signal transducer 9 receives is through impedance matching network 18 prime amplifiers 10, broadband filter 19, program control narrow band filter 5, add to subtracter 8 by the cut signal input end, add phaselocked loop 12 through subtracter 8 and programmable amplifier 11 again, through of short duration frequency-tracking locking process, provide lock flag behind phaselocked loop 12 tracking locks, detecting the output signal frequency of setting DDS signal generator 7 behind the phaselocked loop 12 tracking lock signals from microprocessor 3 is the interfering frequency of phaselocked loop 12 tracking locks, initial phase is zero, initial amplitude is that 1 millivolt sine wave signal exports subtracter 8 to through programmable amplifier 11 adding output signal envelope detecting devices 13, send conversion command for output signal envelope detecting device 13 from microprocessor 3 by control line 14, by output signal envelope detecting device 13 output signal envelope is converted to digital signal, give from microprocessor 3 by data bus 15, adjust the output industrial frequency harmonic signal initial phase of DDS signal generator 7 from microprocessor 3, delay industrial frequency harmonic signal initial phase 1 degree earlier, whether the output signal envelope that judgement is sent here by output signal envelope detecting device 13 reduces, if reduced would continue to delay 7 output industrial frequency harmonic signal initial phases, if output signal envelope increases on the contrary, the industrial frequency harmonic signal initial phases of 7 outputs in advance then are till the difference of twice judged result in front and back is in the scope that error allows.Increase 1 millivolt of 7 output industrial frequency harmonic signal amplitude again, whether the output signal envelope that judgement is sent here by output signal envelope detecting device 13 reduces, if reduced would continue to increase 7 output the industrial frequency harmonic signal amplitudes, if increasing on the contrary, output signal envelope reduces the industrial frequency harmonic signal amplitudes of 7 outputs, till the difference of twice judged result in front and back is in the scope that error allows.From the instruction that microprocessor 3 sends locking output industrial frequency harmonic signal frequency, initial phase and amplitude for DDS signal generator 7 by control line 6, send the industrial frequency harmonic interference for master microprocessor 1 from microprocessor 3 by control bus 16 and follow the tracks of END instruction.Wait for the Next Command of master microprocessor 1.Wherein DDS signal generator 7 output industrial frequency harmonic signal initial amplitude are 1 millivolt and adjust 1 millivolt of industrial frequency harmonic signal amplitude, can determine by the detected useful signal size order of magnitude, if detected useful signal is very weak, these two " 1 millivolts " can change 1 microvolt even littler into so.But the too little meeting of this value makes the tracking lock time elongated.
With the ground nuclear magnetic resonance water witch is example, before each excite magnetic resonance signals, need to charge to power capacitor, this charging process needs several minutes clock times, signal amplifies with collecting part in this time does not have task, just in time can utilize this time to carry out search, tracking and locking work that the industrial frequency harmonic in the useful signal frequency band disturbs, the industrial frequency harmonic during for the detection NMR signal in the filtering useful signal frequency band disturbs ready.Master microprocessor 1 was provided with K switch 1 conducting by control line 2 to the order of sending industrial frequency harmonic interference in the tracking useful signal frequency band from microprocessor 3 and by control line 20 earlier before sending charge command to power capacitor charging control circuit 21, signal transducer 9 is connected to amplifier impedance matching network 18, and then sends charge command for power capacitor 21 and wait for that also beaming back industrial frequency harmonic from microprocessor 3 disturbs the tracking END instruction.From microprocessor 3 according to the Larmor frequency of artificial input or the Larmor frequency that calculates by the measured point latitude or the geomagnetic field intensity of artificial input, centre frequency for program control narrow band filter 5, setting DDS signal generator 7 initial output amplitudes from microprocessor 3 by control line 6 is zero, adds to the cut signal input end of subtracter 8.Near the Larmor frequency that signal transducer 9 receives industrial frequency harmonic undesired signal through impedance matching network 18, prime amplifier 10, broadband filter 19, program control narrow band filter 5 add to subtracter 8 by the cut signal input end, add phaselocked loop 12 through subtracter 8 and programmable amplifier 11 again, frequency-tracking locking process through of short duration provides lock flag behind phaselocked loop 12 tracking locks.After detecting phaselocked loop 12 tracking locks from microprocessor 3 by data line 23, the output signal frequency of setting DDS signal generator 7 by control line 6 from microprocessor 3 is the Larmor frequency of phaselocked loop 12 tracking locks, initial phase is zero, initial amplitude is 1 millivolt, export subtracter 8 to, add output signal envelope detecting device 13 through programmable amplifier 11, by control line 14 control output signal envelope detecting device 13 output signal envelope is converted to digital signal from microprocessor 3, give from microprocessor 3 by data bus 15, adjust the output industrial frequency harmonic signal phase of DDS signal generator 7 from microprocessor 3, delay industrial frequency harmonic signal phase 1 degree earlier, whether the output signal envelope that judgement is sent here by output signal envelope detecting device 13 reduces, if reduced would continue to delay 7 output the industrial frequency harmonic signal phases, if output signal envelope increases on the contrary, the industrial frequency harmonic signal phase of DDS signal generator 7 outputs in advance then is till the difference of twice judged result in front and back is in the scope that error allows.Increase 1 millivolt of the output industrial frequency harmonic signal amplitude of DDS signal generator 7 again, whether the output signal envelope that judgement is sent here by output signal envelope detecting device 13 reduces, if reduced would continue to increase 7 output the industrial frequency harmonic signal amplitudes, if output signal envelope increases on the contrary, then reduce the industrial frequency harmonic signal amplitude of DDS signal generator 7 output, till the difference of twice judged result in front and back is in the scope that error allows.Send the instruction of locking output industrial frequency harmonic signal frequency, phase place and amplitude for DDS signal generator 7 from microprocessor 3 by control line 6, the industrial frequency harmonic interference component that deducts from received signal in the useful signal frequency band during for the reception NMR signal is got ready.Sending industrial frequency harmonic for master microprocessor 1 from microprocessor 3 by control line 16 disturbs the tracking END instruction, waits for the Next Command of master microprocessor 1.Master microprocessor 1 is provided with K switch 1 by control line 20 and turn-offs, for emission nuclear magnetic resonance excitation signal is got ready.
Claims (1)
1, industrial frequency harmonic codan in the useful signal frequency band in a kind of Testing of Feeble Signals instrument, it is characterized in that, master microprocessor (1) is connected with (16) from microprocessor (3) by control line (2), master microprocessor (1) is connected with transmitter (22) through power capacitor charging control circuit (21), master microprocessor (1) is connected with K1 by control line (20), the connecting and disconnecting of control signal sensor (9) and impedance matching network (18), impedance matching network (18) is through prime amplifier (10), broadband filter (19), program control narrow band filter (5) is connected with programmable amplifier (11) with subtracter (8), programmable amplifier (11) is connected with output signal envelope detecting device (13), output signal envelope detecting device (13) by control line (14) and data bus (15) be connected from microprocessor (3), programmable amplifier (11) through control line (17) be connected from microprocessor (3), programmable amplifier (11) is connected with DDS signal generator (7) through phaselocked loop (12), DDS signal generator (7) is connected with subtracter (8), be connected with DDS signal generator (7) by control line (6) from microprocessor (3), be connected with program control narrow band filter (5) by control line (4) from microprocessor (3), be connected with phaselocked loop (12) lock flag end by data line (23) from microprocessor (3).
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| Application Number | Priority Date | Filing Date | Title |
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| CNB200810050580XA CN100562765C (en) | 2008-04-09 | 2008-04-09 | Industrial frequency harmonic codan in the useful signal frequency band in the Testing of Feeble Signals instrument |
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| CNB200810050580XA CN100562765C (en) | 2008-04-09 | 2008-04-09 | Industrial frequency harmonic codan in the useful signal frequency band in the Testing of Feeble Signals instrument |
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| CN101251606A true CN101251606A (en) | 2008-08-27 |
| CN100562765C CN100562765C (en) | 2009-11-25 |
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Cited By (11)
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| CN102053280A (en) * | 2010-11-10 | 2011-05-11 | 吉林大学 | Nuclear magnetic resonance ground water detection system with reference coils and detection method |
| CN101666834B (en) * | 2009-09-15 | 2011-09-21 | 深圳市汇顶科技有限公司 | Industrial frequency-harmonic interference resistant signal sampling method and system |
| CN104502984A (en) * | 2014-12-15 | 2015-04-08 | 吉林大学 | Specific frequency noise canceling underground nuclear magnetic resonance detection device and detection method |
| CN104599183A (en) * | 2014-11-28 | 2015-05-06 | 西安交通大学 | Communication device for program trading |
| CN104898172A (en) * | 2015-05-19 | 2015-09-09 | 吉林大学 | Cross-correlation-based nuclear magnetic resonance full wave signal noise filtering method |
| CN105549097A (en) * | 2015-12-22 | 2016-05-04 | 吉林大学 | Transient electromagnetic signal power frequency and harmonic interference elimination method and apparatus thereof |
| CN107329183A (en) * | 2017-07-14 | 2017-11-07 | 中国地质科学院地球物理地球化学勘查研究所 | A kind of controlled-source audiomagnetotellurics sounding collecting method and device |
| CN109391243A (en) * | 2017-08-08 | 2019-02-26 | 罗德施瓦兹两合股份有限公司 | Amplifier circuit and method |
| CN109633759A (en) * | 2018-12-12 | 2019-04-16 | 吉林大学 | Ground magnetic resonance signal rapidly extracting device and method based on phase lock amplifying technology |
| CN110703343A (en) * | 2019-10-28 | 2020-01-17 | 吉林大学 | Wide-matching-resonance magnetic resonance detection device and detection method based on PWM (pulse-Width modulation) regulation and control technology |
| CN110794463A (en) * | 2019-10-10 | 2020-02-14 | 吉林大学 | Short dead zone magnetic resonance emission device based on wide harmonic matching and control method |
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2008
- 2008-04-09 CN CNB200810050580XA patent/CN100562765C/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101666834B (en) * | 2009-09-15 | 2011-09-21 | 深圳市汇顶科技有限公司 | Industrial frequency-harmonic interference resistant signal sampling method and system |
| CN102053280A (en) * | 2010-11-10 | 2011-05-11 | 吉林大学 | Nuclear magnetic resonance ground water detection system with reference coils and detection method |
| CN102053280B (en) * | 2010-11-10 | 2013-05-01 | 吉林大学 | Nuclear magnetic resonance ground water detection system with reference coils and detection method |
| CN104599183B (en) * | 2014-11-28 | 2018-06-26 | 西安交通大学 | A kind of communication device for sequencing transaction |
| CN104599183A (en) * | 2014-11-28 | 2015-05-06 | 西安交通大学 | Communication device for program trading |
| CN104502984A (en) * | 2014-12-15 | 2015-04-08 | 吉林大学 | Specific frequency noise canceling underground nuclear magnetic resonance detection device and detection method |
| CN104898172A (en) * | 2015-05-19 | 2015-09-09 | 吉林大学 | Cross-correlation-based nuclear magnetic resonance full wave signal noise filtering method |
| CN105549097A (en) * | 2015-12-22 | 2016-05-04 | 吉林大学 | Transient electromagnetic signal power frequency and harmonic interference elimination method and apparatus thereof |
| CN107329183A (en) * | 2017-07-14 | 2017-11-07 | 中国地质科学院地球物理地球化学勘查研究所 | A kind of controlled-source audiomagnetotellurics sounding collecting method and device |
| CN107329183B (en) * | 2017-07-14 | 2019-03-22 | 中国地质科学院地球物理地球化学勘查研究所 | A kind of controlled-source audiomagnetotellurics sounding collecting method and device |
| CN109391243A (en) * | 2017-08-08 | 2019-02-26 | 罗德施瓦兹两合股份有限公司 | Amplifier circuit and method |
| CN109391243B (en) * | 2017-08-08 | 2023-12-22 | 罗德施瓦兹两合股份有限公司 | Amplifier circuit and method |
| CN109633759A (en) * | 2018-12-12 | 2019-04-16 | 吉林大学 | Ground magnetic resonance signal rapidly extracting device and method based on phase lock amplifying technology |
| CN110794463A (en) * | 2019-10-10 | 2020-02-14 | 吉林大学 | Short dead zone magnetic resonance emission device based on wide harmonic matching and control method |
| CN110703343A (en) * | 2019-10-28 | 2020-01-17 | 吉林大学 | Wide-matching-resonance magnetic resonance detection device and detection method based on PWM (pulse-Width modulation) regulation and control technology |
| CN110703343B (en) * | 2019-10-28 | 2021-08-17 | 吉林大学 | Wide-matching-resonance magnetic resonance detection device and detection method based on PWM (pulse-Width modulation) regulation and control technology |
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| CN100562765C (en) | 2009-11-25 |
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