CN101977083A - Ultra wideband stratum communication system - Google Patents
Ultra wideband stratum communication system Download PDFInfo
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- CN101977083A CN101977083A CN2010105248344A CN201010524834A CN101977083A CN 101977083 A CN101977083 A CN 101977083A CN 2010105248344 A CN2010105248344 A CN 2010105248344A CN 201010524834 A CN201010524834 A CN 201010524834A CN 101977083 A CN101977083 A CN 101977083A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B13/00—Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
- H04B13/02—Transmission systems in which the medium consists of the earth or a large mass of water thereon, e.g. earth telegraphy
Abstract
The invention discloses an ultra wideband stratum communication system which is mainly used for solving the problem that no reliable communication means can be taken when a serious accident occurs in a mine well. The ultra wideband stratum communication system comprises two transceivers, a pair of transmitting and receiving common electrodes and a transmitting and receiving changeover switch, a wireless channel is formed through the electrodes by using a stratum as a transmission medium so as to further form a time division duplex communication system. Each transceiver comprises transmitting equipment and receiving equipment, wherein the transmitting equipment comprise a channel coding unit, an M-element spectrum spreading unit and an E-class power amplifier; the receiving equipment comprise a low noise amplifier, a level-isolating straight-coupling capacitor, an AGC (Automatic Gain Control) amplifier, an A/D (Analog to Digital) converter and a dispreading, demodulating and channel decoding unit. A ternary pseudo random code with chip value of -1 or 0 or 1 is taken as an M-element spectrum spreading code, and a push-pull power amplifier with an output transformer is used as the E-class power amplifier. The invention has the advantages of small signal duty ratio, high peak-to-average power ratio, good error code characteristics and long transmission distance, and can provide a reliable communication means for mine well disaster relief.
Description
Technical field
The present invention relates to communication system, a kind of specifically ultra broadband rock stratum communication system can be used for the down-hole emergency communication.
Background technology
Because in a single day serious accident takes place in the coal mine, may cause that the tunnel that leaks, has a power failure, caves in stops up, phenomenons such as telecommunication cable destruction, existing various means of communication all possibly can't be used, aboveground in confused situation for the down-hole, have a strong impact on speedily carry out rescue work, normally the carrying out and actual implementation result of disaster relief work.Adopting the rock stratum communication system in this case, is that transmission medium formation wireless channel communicates with the current field of dipole electrode formation, with the rock stratum, will be a kind of emergency communication means of uniqueness.
200820030023.7) and the system introduced of data such as " based on the digital speech terrane communication machine of software radio " stepped on of 2004 the 1st periodicals of Xian Electronics Science and Technology University's Master's thesis " development of underground very low frequency wireless communication machine " (author Guo Baojuan, tutor Yi Kechu) in 2004, wireless communication technology (author: field red heart, Guo Baojuan, to new, Yi Kechu) existing rock stratum communication system mainly contains utility model patent " the portable terrane communication machine " (application number: of Xi'an coal research institute application.This rock stratum communication system can be carried out numeral or vocoder Speech Communication by the electrode of nail on the rock stratum, but because of it adopts conventional digital modulation mode, produce the continuous wave signal of approximately constant amplitude, and by linear power amplifier amplification back transmission, its power efficiency is lower, thereby its communications distance all is difficult to reach practical requirement with the reliability of communicating by letter, thereby do not drop into practical application as yet so far.Its basic reason is that this terrane communication machine distance that can communicate reliably is too little, signal of communication is decayed very big in the rock stratum, along with the increase signal of distance becomes very faint very soon, and the restriction that required by the underground equipment essential safety, the maximum transmitting power that allows can not be too big, thereby communication distance generally can only reach hundreds of rice.
Summary of the invention
The objective of the invention is to the deficiency at above-mentioned prior art, propose a kind of ultra broadband rock stratum communication system, communication system equipment can met under the condition of essential safety design, the distance that can communicate reliably increases to more than 1500 meters.
The know-why that realizes the object of the invention is: adopt the impulse type ultra broadband spread spectrum communication system of carrierfree modulation, constitute a kind of rock stratum wireless communication system; Its signal of communication is that the smaller and flat power ratio in peak of duty ratio is than higher pulse feature signal, it combines M unit's spread spectrum and the high efficiency E class power amplifier technology based on the ternary pseudo noise code in addition, thereby can be under the condition of the less average transmitting power that meets essential safety, send the pulse signal that driving force is very strong, short-time rating is very big, thereby the distance of reliable communication is enlarged markedly.
According to above-mentioned principle rock stratum provided by the invention communication system, being made of two electrode and transceiver toggle switch that are connected with the transceiver of user terminal, a pair of transmit-receive sharing, is that transmission medium formation current field radio communication channel communicates with the rock stratum by electrode; Each transceiver comprises a transmitting apparatus and a receiving equipment, and this transmitting apparatus comprises chnnel coding unit, spectrum-spreading unit, waveform shaping unit and power amplifier; This receiving equipment comprises low noise amplifier, low pass filter, the at interval straight coupling capacitor of level, AGC amplifier, A/D converter, matched filter, despread unit, demodulation and channel decoding unit, it is characterized in that:
Above-mentioned spectrum-spreading unit adopts chip value to get-1 or 0 or 1 ternary pseudo noise code as spreading code, carries out direct sequence spread spectrum for the digital information of input, is output as the chip sequence behind the spread spectrum; Chip value is that zero number of chips accounts for 75%～94% of total number of chips in each spreading code.
Above-mentioned waveform shaping unit adopts the chip waveform of the two-way rectangular pulse of Digital Logical Circuits generation as spread-spectrum signal, and the chip sequence that spectrum-spreading unit is sent here carries out waveform shaping in chip ground one by one, and this chip sequence is changed into the impulse type waveform signal; Equal 1 chip for chip value, its chip waveform is negative rectangular pulse of a positive rectangular pulse heel, equal-1 chip for chip value, its chip waveform is positive rectangular pulse of a negative rectangular pulse heel, for the chip that chip value equals 0, corresponding output waveform is a zero level; The impulse type waveform signal that so obtains is a kind of carrier free impulse type ultra-broadband digital modulation signal; This signal is divided into positive and anti-phase two paths of signals, and sends power amplifier again to after the negative pulse in the two paths of signals is changed to zero level.
Above-mentioned power amplifier adopts the push-pull power amplifier that output transformer is arranged, and two power tube adopts switching transistor, is operated on off state; The elementary two ends of output transformer are parallel with a capacitor, and this capacitor constitutes the shunt-resonant circuit with the primary inductance of output transformer; Output transformer secondary except two tip nodes, the centre also is provided with a plurality of tapping points, from these contacts, select two according to the formation resistivity situation between two electrodes during application, one of them is linked to each other and ground connection with an electrode, and another is connected to another electrode by transceiver toggle switch.
Above-mentioned spectrum-spreading unit adopts M unit spread spectrum system to carry out direct sequence spread spectrum, wherein M=2
k, the span of this k is 2 to 6 integer; Be input to the digital information of spectrum-spreading unit, its bit rate R by the chnnel coding unit
bSpan be 1～1280 bps, the chip sequence of spectrum-spreading unit output, its spreading rate R
cSpan is 5120～10240 chips/sec.
The two-way rectangular pulse that above-mentioned waveform shaping unit is adopted, its rectangular pulse width T
pSpan be chip duration T
c10%～50%, two rectangular pulses between be provided with gap T
g, the span in this gap is 0%～80% of a chip duration, and satisfies 2T
p+ T
g≤ 1/R
c=T
c, R wherein
cAnd T
cBe respectively the spreading rate and the chip duration of spread-spectrum signal.
The above-mentioned push-pull power amplifier that output transformer is arranged, wherein two power tubes all adopt multiple tube; The emitter-base bandgap grading of a middle power transistor is linked to each other with the base stage of a high power transistor, and the collector electrode of power transistor and the collector electrode of this high power transistor are connected to form a multiple tube in will being somebody's turn to do; So two multiple tubes forming constitute push-pull power amplifier with output transformer, are operated on off state.
The collector electrode of above-mentioned two multiple tubes is connected respectively to the elementary two ends of output transformer, and the emitter-base bandgap grading of these two multiple tubes links to each other and ground connection.The elementary centre cap of output transformer is connected to the anode of dc power supply by one 0.5 ohm current-limiting resistance, and the current-limiting resistance two ends are parallel with one 20 micro farad capacitor.
The capacitor of above-mentioned output transformer elementary two ends parallel connection, span are 0.1～0.3 microfarad; The inductance of this capacitor and output transformer primary coil constitutes the shunt-resonant circuit, and the resonance frequency of this resonant tank is designed between 5000Hz～10000kHz.
Above-mentioned low pass filter adopts active low-pass filter or switching mode low pass filter, and its amplitude-frequency response is reduced to-bandwidth during 3dB, is designed to equal the waveform signal spectrum amplitude that the waveform shaping unit produced be reduced to-bandwidth during 10dB.
The sample frequency of above-mentioned A/D converter is taken as more than 2 times of described low pass filter bandwidth.
Matched filter in the above-mentioned receiving equipment adopts digital transversal filter, and its unit impulse response responds mutually by the discrete form of chip waveform and total channel unit impulse that convolution obtains.
Above-mentioned transceiver toggle switch, adopt the electromagnetic relay or the electronic switch of single-pole double throw or dpdt double-pole double-throw (DPDT), be used to realize the time division duplex communication mode, promptly control electrode links to each other with the low noise amplifier of transceiver when receiving, and links to each other with the secondary of output transformer of transceiver when sending.
The present invention has following advantage:
1) spectrum-spreading unit of the present invention, carry out direct sequence spread spectrum as spreading code for the digital information of input owing to adopt chip value to get-1 or 0 or 1 ternary pseudo noise code, chip value is that zero number of chips accounts for 75%～94% of total number of chips in each spreading code; This chip sequence of spectrum-spreading unit output is converted into the impulse type waveform signal in the waveform shaping unit, it is a kind of carrier free impulse type ultra-broadband digital modulation signal.The duty ratio of this signal is very little, the flat power ratio in peak is very high, and this just makes system meet under the maximum average power restriction of essential safety designing requirement at equipment, sends very big peak power, so that reach farther communication distance.
2) spectrum-spreading unit of the present invention owing to adopt M unit spread spectrum to have the advantage of approaching to shannon limit, makes that the Normalized Signal/Noise Ratio that requires obviously reduces when reaching no error code and transmitting, and helps increasing the ultimate range that communicates reliably.
3) power amplifier in the transmitting apparatus of the present invention, owing to adopt a kind of push-pull power amplifier that output transformer is arranged that is operated on off state, its power efficiency is significantly higher than conventional linear power amplifier, particularly when it is used to amplify the very little pulse signal of duty ratio, still has very high efficient; And the output impedance of this power amplifier is very low, is similar to constant pressure source, thereby when the electrode load resistance sizes changed in very on a large scale, it can both keep very high power feed efficient; In addition, because chip waveform shaping unit output is that the sparse positive rectangular pulse of two-way removes driving switch type push-pull power amplifier, thereby not only drive circuit is simple, and drives efficiently very high.
Comprehensive above-mentioned three advantages as can be known, rock stratum communication system equipment designed according to this invention can increase the ultimate range that can communicate reliably significantly meeting under the prerequisite that down-hole electric equipment essential safety requires.
In addition, the present invention is because the mode that adopts clock periodically to control transceiver toggle switch automatically realizes time division duplex communication mode completely, for bi-directional speech communication provides assurance, having overcome existed system can only switch the defective that realizes the half-duplex operation mode by artificial transmitting-receiving.
Description of drawings
Fig. 1 is the structured flowchart of ultra broadband of the present invention rock stratum communication system;
Fig. 2 is the structured flowchart of transceiver of the present invention;
Fig. 3 is the waveform shaping unit produced in the system of the present invention transmitting apparatus the chip value oscillogram for+1 o'clock;
Fig. 4 is the waveform shaping unit produced in the system of the present invention transmitting apparatus the chip value oscillogram for-1 o'clock;
Fig. 5 is the power amplifier schematic diagram in the transmitting apparatus of the present invention.
Embodiment
Embodiment 1
With reference to Fig. 1, ultra broadband provided by the invention rock stratum communication system is made of two electrode and transceiver toggle switch that are connected with the transceiver of user terminal, a pair of transmit-receive sharing.Link to each other as a side with first transceiver with first user terminal, link to each other as the opposing party with second transceiver with second user terminal, respectively having the electrode of a pair of nail on the rock stratum to send received signal by two sides, is that transmission medium formation current field radio communication channel communicates with the rock stratum.
With reference to Fig. 2, each transceiver comprises a transmitting apparatus and a receiving equipment.This transmitting apparatus includes chnnel coding unit, spectrum-spreading unit, waveform shaping unit and power amplifier; This receiving equipment includes low noise amplifier, low pass filter, the at interval straight coupling capacitor C of level, AGC amplifier, A/D converter, matched filter, despread unit, demodulation and channel decoding unit.Wherein:
The chnnel coding unit, the digital information that is used for to user terminal to be produced is carried out chnnel coding, and this chnnel coding adopts in conjunction with the RS sign indicating number that interweaves, the bit rate R of the digital information that obtains behind the coding
b=1.25,10,80,640,1280 bps, when using, choose wherein a kind of bit rate by the user at every turn communicate.
Spectrum-spreading unit is used for the digital information of chnnel coding unit input is carried out spread spectrum, and the bit rate of its input information is R
bBps, input information carries out becoming the output of spread-spectrum code chip sequence behind the spread spectrum in spectrum-spreading unit, and its spreading rate is R
c=5120 chips/sec.Used spread spectrum system adopts M unit spread spectrum, gets M=16, the bit number k=4 of each information symbol correspondence, and promptly per 4 bits are regarded a symbol as, carry out spread spectrum with 16 mutually orthogonal ternary pseudo noise codes, so bit rate is R
bInput digit information to become character rate be R
s=R
bThe symbol sebolic addressing of/4 symbol/seconds, the above-mentioned 5 kinds of different bit rates corresponding to input digit information have 5 kinds of different character rates, i.e. R
s=0.3125,2.5,20,160,320 baud/seconds.。Employing length is N=R
c/ R
sThe ternary pseudo noise code as spreading code, this symbol sebolic addressing is carried out M unit spread spectrum.At every kind of character rate, respectively design the ternary pseudo noise code of 16 mutual nearly orthogonals in advance, a spreading code set of formation is stored in the spectrum-spreading unit standby.The length of spreading code is respectively N=R among these 5 spreading code set
c/ R
s=16384,2048,256,32,16.Required spreading code adopts the computer search method to produce in the design phase, and the value of each chip has-1,0,1 three kinds of selections, and each spreading code value is that zero number of chips accounts for 3/4 of the total number of chips of whole spreading code, i.e. r
0=3/4.
The chip forming unit, the spread-spectrum signal chip sequence that is used to spectrum-spreading unit is sent here is realized waveform shaping.Adopt the chip waveform of the two-way rectangular pulse of Digital Logical Circuits generation as spread-spectrum signal, the chip sequence that spectrum-spreading unit is sent here carries out waveform shaping in chip ground one by one, and this chip sequence is changed into the impulse type waveform signal.For the chip that chip value equals 1, its waveform is that a width is T
pWidth of positive rectangular pulse heel of=65 microseconds is T
pThe negative rectangular pulse of=65 microseconds, the zero level gap between the two is T
g=22 microseconds, as shown in Figure 3; For the chip that chip value equals-1, its waveform is a T
pT of negative rectangular pulse heel
pPositive rectangular pulse, the zero level gap between the two is T
g, as shown in Figure 4; 2T herein
p+ T
g=152 microseconds satisfy 2T
p+ T
g≤ 1/R
c=T
c=195.3125 microseconds, wherein T
cChip duration for spread-spectrum signal.So the impulse type waveform signal that forms is a kind of carrier free impulse type ultra-broadband digital modulation signal; This unit further is divided into this signal positive and anti-phase two paths of signals, and sends power amplifier again to after the negative pulse in the two paths of signals is changed to zero level.
Power amplifier adopts the push-pull power amplifier that output transformer is arranged, and as shown in Figure 5, it is by two multiple tubes, transformer and peripheral components R
1～R
5Form.T wherein
1And T
2Be not less than 500 milliamperes middle power switch transistor for maximum collector current; T
3And T
4Be not less than 10 amperes middle power switch transistor for maximum collector current.T
1Emitter-base bandgap grading and T
3Base stage link to each other T
1Collector electrode and T
3Collector electrode link to each other T
1With T
3Constitute a multiple tube together; T
2Emitter-base bandgap grading and T
4Base stage link to each other T
2Collector electrode and T
4Collector electrode link to each other T
2With T
4Constitute another multiple tube together.These two multiple tubes constitute push-pull power amplifier with output transformer, are operated on off state.The collector electrode of these two multiple tubes is connected respectively to the elementary L of output transformer
1Two ends, the elementary centre cap of output transformer is by a current-limiting resistance R
5Be connected to+anode of 5 volts of DC power supply, get R
5=0.5 ohm; R
5Two ends are parallel with one 20 micro farad capacitor C
pThe emitter-base bandgap grading of these two multiple tubes links to each other and ground connection; Introduce by the base stage of two multiple tubes respectively by the two-way waveform signal that the waveform shaping unit sends; Be connected on two resistance R between input and the base stage
1And R
2For the base stage current-limiting resistance, be respectively applied for restricted T
1And T
2Base current, in order to avoid its collector current surpasses maximum permissible value, R
1And R
2Span is 250～2500 ohm, passes through test T in the debug phase
1And T
2Collector saturation voltage and the state set electrode current size size of determining these two resistance.Be connected in parallel on two resistance R between base stage and the ground
3And R
4Be respectively T
1And T
2The base stage below-center offset, value is R
1=R
2=2000 ohm.The elementary two ends of described output transformer capacitor in parallel, its value C
0=0.2 μ f, the elementary inductor design of output transformer is 5 milihenries, parallel resonance frequency is 5kHz.The output transformer secondary coil is 6: 1 with the ratio of the total number of turns of primary coil; Secondary coil is except two end points, and middle two taps in addition lay respectively at 1/3 place and 5/9 place.According to the situation of formation resistivity between two electrodes, select two from 4 connector lugs of transformer secondary output during application, one of them joint links to each other with electrode 1, and ground connection, and another joint is connected to electrode 2 by transceiver toggle switch.
Transceiver toggle switch, adopt micro electromagnetic relay, be used to control the transmitting-receiving switching of an electrode, " cutter " node of relay links to each other with this electrode, and two " throws " node A and B, connects the input and a secondary tap of power amplifier output transformer of described low noise amplifier respectively; Another electrode continuous earth; In the time will sending, " cutter " node that links to each other with electrode is communicated with " throwing " node B, and disconnects with A; And in the time will receiving, " cutter " node is communicated with " throwing " node A, and disconnects with B; So realize time division duplex, available minute frame timing automatic of the driving of this relay carried out, and the time division duplex frame length is taken as T
D=0.2 second.When needs carried out half-duplex mode communication, transceiver toggle switch became artificially manually control.
Low noise amplifier adopts the alap special chip of noise level to realize that its gain is designed to 20dB.
Low pass filter adopts 4 rank switching capacity type active filter chips to realize.Because it is T that aforementioned chip waveform adopts width
pThe two-way rectangular pulse of=65 microseconds, its spectrum amplitude drop to-and bandwidth during 10dB is about f
B=1.8/T
p=27700Hz, thus the amplitude of low pass filter drop to-bandwidth during 3dB is taken as 27700Hz.
The at interval straight coupling capacitor of level, in order to the DC component in the erasure signal, its value is taken as the C=0.05 microfarad.
The AGC amplifier, be automatic gain control amplifier, adopt two high gain operational amplifier chips and digital regulation resistance to realize that the closed loop gain of two operational amplifiers all is designed to 45dB, adopt digital regulation resistance control overall gain to change dynamic range 40dB adaptively.The automatic control of its gain is: by the short-time average magnitude that detects received signal after the A/D conversion automatically and quasi real time, and calculate the signal amplitude of expectation and the ratio of detected actual signal short-time average magnitude, this ratio is used for the control figure potentiometer, make the short-time average magnitude approximate constant of actual signal, the short-time average magnitude of the desired signal here is taken as 1/32 of A/D converter output maximum signal amplitudes.
The A/D converter, sample frequency is taken as f
s=56320Hz, this frequency drops to-2 times of 3dB Time Bandwidth greater than the low pass filter amplitude response.The A/D converter selects for use quantified precision to realize more than or equal to the chip of 12 bits.
Matched filter adopts digital transversal filter, and its unit impulse response is the convolution of the discrete form of chip waveform with total channel unit impulse response, and total channel unit impulse responds to test by field experiment and obtains.
Despread unit is used for the signal of sending here from matched filter is carried out the sync correlation despreading, and the local spreading code that is adopted is identical with the spreading code in the transmitting apparatus.
Demodulation and channel decoding unit adopt the RS code decoder in conjunction with deinterleaving, and the demodulation coding algorithm is corresponding with modulation and coding unit in the transmitting apparatus.
The communication process of whole system is as follows:
From the transmitting apparatus of a transceiver be: the digital information that user terminal produces to the process of the receiving equipment transmission digital information of another transceiver, after delivering to the chnnel coding unit and encoding, be transported to and carry out spread spectrum in the spectrum-spreading unit, after becoming the spread-spectrum code chip sequence, be transported to the waveform shaping that realizes chip in the waveform shaping unit and change the impulse type waveform signal into, amplify through push-pull power amplifier then, by transceiver toggle switch signal is outputed to the electrode of nail on the rock stratum again and send.
Receiving equipment receives the process by the digital information that transmitting apparatus sent in another transceiver and is in transceiver: by nail after the electrode on the rock stratum receives signal, delivering to low noise amplifier through transceiver toggle switch amplifies, signal after the amplification is delivered to low pass filter filtering again, filtered signal is delivered to the AGC amplifier through the at interval straight coupling capacitor of level again and is amplified, signal after the amplification becomes digital signal through the A/D converter again, this digital signal is after matched filter filtering, in despread unit, realize despreading again, after demodulation and channel decoding unit recover the digital information that the other side sends.
Embodiment 2
System configuration and communication process and embodiment 1 are identical, but the technical parameter of each unit will be done following modification, and unlisted content and embodiment 1 are identical.
The chnnel coding unit, identical with embodiment 1, the bit rate of coding back digital information still is R
b=1.25,10,80,640,1280 bps.
Spectrum-spreading unit adopts M unit spread spectrum, M=16, k=4; Character rate corresponding to above-mentioned 5 kinds of information rates still is R
s=0.3125,2.5,20,160,320 baud/seconds; But the spread-spectrum code chip modifying rates is R
c=10240 chips/sec, corresponding spreading code code length N=R
c/ R
s=32768,4096,512,64,32; 0 value chip proportion is revised as r in the ternary spread spectrum sign indicating number
0=15/16, all the other are identical with embodiment 1.The waveform shaping unit, rectangular pulse width T
p=42 microseconds, the gap T between the positive negative pulse stuffing
g=13 microseconds; 2T
p+ T
g=97 microseconds satisfy 2T
p+ T
g≤ 1/R
c=T
c=97.65625 microseconds, all the other are identical with embodiment 1.
Power amplifier, parallel resonance capacitor C
0=0.1 μ f, output transformer primary inductance L
0=2.5 milihenries, parallel resonance frequency 10kHz, all the other are identical with embodiment 1.
Transceiver toggle switch is identical with embodiment 1.
Low pass filter adopts 4 rank switching capacity type active filters, and amplitude response is reduced to-and bandwidth during 3dB is taken as f
B=1.8/T
p=42857Hz.
The A/D converter, sample frequency f
s=92160Hz, sample quantization precision 12 bits.
Embodiment 3
System configuration and communication process and embodiment 1 are identical, but the technical parameter of each unit will be done following modification, and unlisted content and embodiment 1 are identical.
The chnnel coding unit, identical with embodiment 1, the bit rate of coding back digital information still is R
b=1.25,10,80,640,1280 bps.
Spectrum-spreading unit adopts M unit spread spectrum, M=4, k=2; Character rate corresponding to above-mentioned 5 kinds of information rates is R
s=0.625,5,40,320,640 baud/seconds; But spread-spectrum code chip speed is R
c=7680 chips/sec, corresponding spreading code code length N=R
c/ R
s=12288,1536,192,24,12; 0 value chip proportion is r in the ternary spread spectrum sign indicating number
0=11/12.
The waveform shaping unit, rectangular pulse width T
p=54 microseconds, the gap T between the positive negative pulse stuffing
g=16 microseconds; 2T
p+ T
g=124 microseconds satisfy 2T
p+ T
g≤ 1/R
c=T
c=130.2 microseconds.
Power amplifier, parallel resonance capacitor C
0=0.2 μ f, output transformer primary inductance L
0=1 milihenry, parallel resonance frequency 7700kHz.
Transceiver toggle switch is identical with embodiment 1.
Low pass filter adopts 4 rank switching capacity type active filters, and amplitude response is reduced to-and bandwidth during 3dB is taken as f
B=1.8/T
p≈ 33400Hz.
A/D converter, sample frequency are f
s=69120Hz, sample quantization precision 12 bits.
Embodiment 4
System configuration and communication process and embodiment 1 are identical, but the technical parameter of each unit will be done following modification, and unlisted content and embodiment 1 are identical.
The chnnel coding unit, identical with embodiment 1, the bit rate of coding back digital information still is R
b=1.25,10,80,640,1280 bps.
Spectrum-spreading unit adopts M unit spread spectrum, M=64, k=6; Character rate corresponding to above-mentioned 5 kinds of information rates is R
s=0.2083,1.6667,13.3333,106.6667,213.3333 baud/seconds; But spread-spectrum code chip speed is R
c=7680 chips/sec, corresponding spreading code code length N=R
c/ R
s=36864,4608,576,72,36; 0 value chip proportion is r in the ternary spread spectrum sign indicating number
0=7/8.
The waveform shaping unit, rectangular pulse width T
p=54 microseconds, the gap T between the positive negative pulse stuffing
g=16 microseconds; 2T
p+ T
g=124 microseconds satisfy 2T
p+ T
g≤ 1/R
c=T
c=130.2 microseconds.
Power amplifier, parallel resonance capacitor C
0=0.2 μ f, output transformer primary inductance L
0=1 milihenry, parallel resonance frequency 7700kHz.
Transceiver toggle switch adopts two electronic switches, a break-make that is used between control electrode 2 and the transformer, and another is used for the break-make between control electrode 2 and the low noise amplifier.
Low pass filter adopts 4 rank switching capacity type active filters, and amplitude response is reduced to-and bandwidth during 3dB is taken as f
B=1.8/T
p=33400Hz.
A/D converter, sample frequency are f
s=69120Hz, sample quantization precision 12 bits.
Above example is several preferred embodiment of the present invention; do not constitute any limitation of the invention; obviously anyone can carry out suitable modification under thought of the present invention, but any to parameter modification and other examples of obtaining all belong to the row of protection scope of the present invention.
Claims (10)
1. a ultra broadband rock stratum communication system is made of two electrode and transceiver toggle switch that are connected with the transceiver of user terminal, a pair of transmit-receive sharing, is that transmission medium formation current field radio communication channel communicates with the rock stratum by electrode; Each transceiver comprises a transmitting apparatus and a receiving equipment, and this transmitting apparatus comprises chnnel coding unit, spectrum-spreading unit, waveform shaping unit and power amplifier; This receiving equipment comprises low noise amplifier, low pass filter, the at interval straight coupling capacitor of level, AGC amplifier, A/D converter, matched filter, despread unit, demodulation and channel decoding unit, it is characterized in that:
Described spectrum-spreading unit adopts chip value to get-1 or 0 or 1 ternary pseudo noise code as spreading code, carries out direct sequence spread spectrum for the digital information of input, is output as the chip sequence behind the spread spectrum; Chip value is that zero number of chips accounts for 75%～94% of total number of chips in each spreading code;
Described waveform shaping unit adopts the chip waveform of the two-way rectangular pulse of Digital Logical Circuits generation as spread-spectrum signal, and the chip sequence that spectrum-spreading unit is sent here carries out waveform shaping in chip ground one by one, and this chip sequence is changed into the impulse type waveform signal; Equal 1 chip for chip value, its chip waveform is negative rectangular pulse of a positive rectangular pulse heel, equal-1 chip for chip value, its chip waveform is positive rectangular pulse of a negative rectangular pulse heel, for the chip that chip value equals 0, corresponding output waveform is a zero level; So the impulse type waveform signal that forms is a kind of carrier free impulse type ultra-broadband digital modulation signal; This signal is divided into positive and anti-phase two paths of signals, and sends power amplifier again to after the negative pulse in the two paths of signals is changed to zero level;
Described power amplifier adopts the push-pull power amplifier that output transformer is arranged, and two power tube adopts switching transistor, is operated on off state; The elementary two ends of output transformer are parallel with a capacitor, and this capacitor constitutes the shunt-resonant circuit with the primary inductance of output transformer; Output transformer secondary except two tip nodes, the centre also is provided with a plurality of tapping points, from these contacts, select two according to the formation resistivity situation between two electrodes during application, one of them is linked to each other and ground connection with an electrode, and another is connected to another electrode by transceiver toggle switch.
2. rock stratum according to claim 1 communication system is characterized in that: spectrum-spreading unit adopts M unit spread spectrum system to carry out direct sequence spread spectrum, wherein M=2
k, the value of this k is 2 to 6 integer; Be input to the digital information of spectrum-spreading unit, its bit rate R by the chnnel coding unit
bSpan be 1.25～1280 bps, the chip sequence of spectrum-spreading unit output, its spreading rate R
cSpan is 5120～10240 chips/sec.
3. rock stratum according to claim 1 communication system is characterized in that: the two-way rectangular pulse that described waveform shaping unit is adopted, its rectangular pulse width T
pSpan be chip duration T
c10%～50%, two rectangular pulses between be provided with gap T
g, the span in this gap is 0%～80% of a chip duration, and satisfies 2T
p+ T
g≤ 1/R
c=T
c, R wherein
cAnd T
cBe respectively the spreading rate and the chip duration of spread-spectrum signal.
4. rock stratum according to claim 1 communication system is characterized in that: the described push-pull power amplifier that output transformer is arranged, and wherein two power tubes all adopt multiple tube; The emitter-base bandgap grading of a middle power transistor is linked to each other with the base stage of a high power transistor, and the collector electrode of power transistor and the collector electrode of this high power transistor are connected to form a multiple tube in will being somebody's turn to do; So two multiple tubes forming constitute push-pull power amplifier with output transformer, are operated on off state.
5. rock stratum according to claim 4 communication system is characterized in that: the collector electrode of two multiple tubes is connected respectively to the elementary two ends of output transformer, and the emitter-base bandgap grading of these two multiple tubes links to each other and ground connection; The elementary centre cap of output transformer is connected to the anode of dc power supply by one 0.5 ohm current-limiting resistance, and the current-limiting resistance two ends are parallel with one 20 micro farad capacitor.
6. rock stratum according to claim 1 communication system is characterized in that: the capacitor of output transformer elementary two ends parallel connection, span are 0.1～0.3 microfarad; The inductance of this capacitor and output transformer primary coil constitutes the shunt-resonant circuit, and the resonance frequency of this resonant tank is designed between 5000Hz～10000Hz.
7. rock stratum according to claim 1 communication system, it is characterized in that: described low pass filter adopts active low-pass filter or switching mode low pass filter, its amplitude-frequency response is reduced to-bandwidth during 3dB, be designed to equal the waveform signal amplitude spectrum that the waveform shaping unit produced be reduced to-bandwidth during 10dB.
8. rock stratum according to claim 1 communication system is characterized in that: the sample frequency of described A/D converter is taken as more than 2 times of described low pass filter bandwidth.
9. according to the described rock stratum of claim 1 communication system, it is characterized in that: the matched filter in the described receiving equipment, adopt digital transversal filter, its unit impulse response responds mutually by the discrete form of chip waveform and total channel unit impulse that convolution obtains.
10. rock stratum according to claim 1 communication system, it is characterized in that: described transceiver toggle switch, adopt the electromagnetic relay or the electronic switch of single-pole double throw or dpdt double-pole double-throw (DPDT), be used to realize the time division duplex communication mode, be that control electrode links to each other with the low noise amplifier of transceiver when receiving, and when sending, link to each other with the secondary of output transformer of transceiver.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010524834 CN101977083B (en) | 2010-10-29 | 2010-10-29 | Ultra wideband stratum communication system |
| PCT/CN2011/076903 WO2012055265A1 (en) | 2010-10-29 | 2011-07-06 | Transmitting device, receiving device, transceiver and ultra wideband rock layer communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010524834 CN101977083B (en) | 2010-10-29 | 2010-10-29 | Ultra wideband stratum communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101977083A true CN101977083A (en) | 2011-02-16 |
| CN101977083B CN101977083B (en) | 2013-06-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201010524834 Expired - Fee Related CN101977083B (en) | 2010-10-29 | 2010-10-29 | Ultra wideband stratum communication system |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN101977083B (en) |
| WO (1) | WO2012055265A1 (en) |
Cited By (5)
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| WO2012055265A1 (en) * | 2010-10-29 | 2012-05-03 | 西安电子科技大学 | Transmitting device, receiving device, transceiver and ultra wideband rock layer communication system |
| CN102721982A (en) * | 2012-06-26 | 2012-10-10 | 中国科学院电工研究所 | Ground electromagnetic prospecting method based on SPSP (Spread Spectrum) coding technology and detection system thereof |
| CN103023581A (en) * | 2012-12-14 | 2013-04-03 | 陈曦鸣 | Grounding two-way digital information communication device utilizing ground electric field detection technology |
| CN105871408A (en) * | 2016-03-31 | 2016-08-17 | 青岛海信电器股份有限公司 | Front-end circuit of radio-frequency chip and signal transmission method |
| CN115529058A (en) * | 2022-06-16 | 2022-12-27 | 中煤科工集团西安研究院有限公司 | Mining emergency wireless communication device and communication method |
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| CN201256389Y (en) * | 2008-08-21 | 2009-06-10 | 煤炭科学研究总院西安研究院 | Portable strata communication machine |
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| CN101977083B (en) * | 2010-10-29 | 2013-06-12 | 西安电子科技大学 | Ultra wideband stratum communication system |
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| CN201256389Y (en) * | 2008-08-21 | 2009-06-10 | 煤炭科学研究总院西安研究院 | Portable strata communication machine |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012055265A1 (en) * | 2010-10-29 | 2012-05-03 | 西安电子科技大学 | Transmitting device, receiving device, transceiver and ultra wideband rock layer communication system |
| CN102721982A (en) * | 2012-06-26 | 2012-10-10 | 中国科学院电工研究所 | Ground electromagnetic prospecting method based on SPSP (Spread Spectrum) coding technology and detection system thereof |
| CN102721982B (en) * | 2012-06-26 | 2014-08-13 | 中国科学院电工研究所 | Ground electromagnetic prospecting method based on SPSP (Spread Spectrum) coding technology and detection system thereof |
| CN103023581A (en) * | 2012-12-14 | 2013-04-03 | 陈曦鸣 | Grounding two-way digital information communication device utilizing ground electric field detection technology |
| CN105871408A (en) * | 2016-03-31 | 2016-08-17 | 青岛海信电器股份有限公司 | Front-end circuit of radio-frequency chip and signal transmission method |
| CN105871408B (en) * | 2016-03-31 | 2019-02-26 | 青岛海信电器股份有限公司 | A kind of method of front-end circuit and the signal transmission of radio frequency chip |
| CN115529058A (en) * | 2022-06-16 | 2022-12-27 | 中煤科工集团西安研究院有限公司 | Mining emergency wireless communication device and communication method |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2012055265A1 (en) | 2012-05-03 |
| CN101977083B (en) | 2013-06-12 |
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