CN2289250Y

CN2289250Y - Underground detecting radar transmitter

Info

Publication number: CN2289250Y
Application number: CN 96239308
Authority: CN
Inventors: 张俊荣; 刘凤玉
Original assignee: Changchun Institute of Geography of CAS
Current assignee: Changchun Institute of Geography of CAS
Priority date: 1996-12-10
Filing date: 1996-12-10
Publication date: 1998-08-26
Anticipated expiration: 2006-12-10

Abstract

The utility model relates to an underground detecting radar transmitter, which is composed of a crystal oscillator (1), a trigger signal shaping matcher (2), a large-amplitude step voltage generator (3), a pulse former (4) and a knot-shaped transmitting antenna (5). The utility model can feed balanced discharge pulse of +/-150V with pulse width of 7 ns (at 0.1 height), and can be used for the transmitters of shock pulse radars for various required subsurface investigation.

Description

The underground detection radar transmitter

The invention belongs to the radar transmitter field, be specifically related to be used for the pulse radar transmistter of subsurface investigation.

People have carried out research to underground detection radar energetically from the sixties, wish to develop object and the configuration state thereof that can see underground existence as the air detection radar clearly, in real time.Underground detection radar survey to similarly being the part below the earth surface, basically being made of soil, rock and water body, is to belong to non-homogeneous lossy dielectric, and electromagnetic wave is propagated complexity therein, loss is big, and this development of giving underground detection radar brings very big difficulty to technical theoretically.Require to have enough investigation depths, (1 meter, several meters even hundreds of rice) to require that again enough resolution is arranged (meter level is to centimetre-sized) to subsurface investigation.Through theoretical analysis and actual tests, think effect when the ground penetrating radar of shock pulse system can both reach good than other systems on investigation depth and resolution, be current application and improve the main underground detection radar that improves.

The shock pulse underground detection radar is by time base control system, and emission coefficient, receiving system, Flame Image Process, reconstruction, storage, display system are formed.The gordian technique that exists is that (1) produces significantly, high power, high repetition frequency ns width-pulse, (2) sampling of big bandwidth reduction ratio shows receiver, (3) to the complete machine co-ordination, handle receiving underground signal, the tomographic reconstruction of image, storage shows, the balancedunbalanced switch technology between (4) solution antenna and underground coupling, antenna and transmitter, receiver.These four gordian technique restrictions land down and survey Radar Development and application, are the emphasis of researching and developing up to now.

The present invention utilizes that transistor produces when UHV (ultra-high voltage) is used gets over avalanche effect and obtains the transponder pulse of strong ns width-pulse as underground detection radar, take to export the snowslide pulse simultaneously from collector and emitter, ns high power pulse through differential acquisition ± symmetry, directly present be sent to antenna underground, employing has the bowtie-shaped antenna of broadband character, and antenna loads to improve bandwidth.Emissive source is with 50 Ω internal resistances, the 100KHz frequency, and to knot antenna feed ± 150V, pulsewidth 7ns (0.1 highly place) balance transponder pulse.

Fig. 1 is a underground detection radar transmitter principle block scheme.It is by crystal oscillator (1), trigger pip shaping adaptation (2), step voltage generator (3), pulse shaping adaptation (4), bowtie-shaped emitting antenna (5) are formed significantly.Fig. 2 is a circuit diagram.It is characterized in that producing degree of stability is 10 ^-5, frequency is that the crystal oscillator (1) of the square-wave signal of 100KHz is by quartz crystal JNB, coupling capacitance C ₁Gate circuit D with three series connection ₁, D ₂, D ₃And triode G ₁And resistance R ₃The emitter-base bandgap grading root that constitutes is formed with device, and the trigger pip shaping adaptation (2) that obtains 2us, 5V positive pulse is by capacitor C ₃And resistance R ₅The differentiating circuit that constitutes, the gate circuit D of series connection ₄, D ₅Reach the triode G that signal is divided into two-way ₂And R ₆The emitter follower that constitutes constitutes, the triode G of the input end of trigger pip shaping adaptation (2) and crystal oscillator (1) ₁Emitter be connected, produce at a high speed, the generator of step voltage significantly (3) of transition voltage is by pulse transformer T and avalanche transistor G significantly ₃Constitute, trigger pip shaping adaptation (2) and significantly between the step voltage generator (3) via capacitor C ₄And resistance R ₇The differentiating circuit that constitutes connects, C ₄Meet the triode G of (2) ₂Emitter, R ₇Connect the input end of pulse transformer T, generation ± 150V, the exomonental pulse shaping adaptation of 7ns pulsewidth (4) are by being connected on avalanche transistor G respectively ₃Collector and emitter on two fully symmetry by C ₅And R ₁₀, C ₆And R ₁₁The circuit that constitutes is formed, C ₅And C ₆Respectively with G ₃Collector and emitter link to each other, the sheet metal that the bowtie-shaped emitting antenna (5) of transponder pulse signal is arranged relatively by the collar point of two identical neck shape structures constitutes, between two sheet metals of the broadside of each knot and be connected with ten identical pull-up resistors of resistance, two input heads by respectively with the resistance R of pulse shaping adaptation (4) ₁₀And R ₁₁The noninductive plug feedback that is connected connects.

Crystal oscillator (1) is to be made of series connection quartz crystal and gate circuit, produces the square-wave signal of 100KHz, degree of stability 10 ^-5, through 3DK ₄Emitter follower is delivered to trigger pip shaping adaptation (2).In (2) behind the electric capacity of 100Pf and the differential of 3K Ω resistance (2K Ω potentiometer is finely tuned differential), two doors by series connection obtain wide 2 μ s5V positive pulses, through emitter resistance is to be divided into two-way behind the emitter follower of 430 Ω, one the tunnel goes receiver to produce the stepping sampled signal, one the tunnel behind 6.3pf electric capacity and 680 Ω resistance differential, trigger step voltage generator (3) significantly by the pulse transformer coupling.(3) be the transistor that is used under the UHV (ultra-high voltage) state, when trigger pip triggers, produce and get over snowslide phenomenon, obtain at a high speed, transition voltage significantly.The snowslide transistor is connected into the working forms of collector and emitter series connection equal and opposite in direction resistance, under triggering in trigger pip, can obtain equal and opposite in direction, the step voltage that direction is opposite respectively on collector and emitter.Pulse shaping adaptation (4) is to be made of two 35pf50 Ω circuit that are connected on respectively on the collector and emitter.At a high speed transition voltage obtains after through (4) on 50 Ω resistance ± 150V significantly, the transponder pulse of 7ns pulsewidth (0.1 highly locates).This transponder pulse with " " be reference point balance output.Two input head feedbacks by noninductive plug and bowtie-shaped emitting antenna (5) connect.(5) shape and size are shown in figure (3).The pulse of emission is that repetition frequency is 100KHz, pulsewidth 7ns.Require emitting antenna that the bandwidth of 100KHz-143MHz is arranged.All oscillator form antennas all belong to the arrowband resonant antenna, are difficult to accomplish broadband performance like this.The bowtie-shaped antenna has bandwidth performance preferably, but also not enough, and loading is in order to improve bandwidth performance.

Not that any transistor all has the snowslide of getting over performance, but select BV _CEOHigher, BV _CBHigher, the β value is big as far as possible, f _TThe transistor as quickly as possible of height, or switching time as far as possible.Be exactly that same model triode neither all have the snowslide performance, so the triode that will select the snowslide performance to meet the requirements with experimental method.

Transmitter of the present invention uses on the underground detection radar of oneself developing, obtains to survey dark pipeline and the 8m bathile profile image of underground 2-5 rice.

Fig. 1 underground detection radar transmitter principle block scheme;

Fig. 2 circuit diagram;

Fig. 3 bowtie-shaped sending antenna structure figure;

Embodiment, crystal oscillator select the JN3 quartz crystal for use, 5 gate circuit D ₁-D ₅Select a slice CO36B for use, G ₁And G ₂Select 3DK for use ₄, G ₃Select 3DA87E for use and add the heat radiator of 15 * 15 * 10mm.Transformer T selects Φ 10 toroidal cores for use, each seven circle of primary and secondary.The shape and size of knot antenna (5) as shown in the figure, adopt the thick copper coin of 1mm, long is 500mm, the width of knot broadside and between the upper and lower apart from being respectively 100mm, load on the both ends of the surface is the resistance of 820 Ω of 10 parallel connections, two knot spacings are 25mm, and the resistance that top adds 75 Ω shields.Capacitor C ₁Be 36pf, C ₂Be 22 μ f, C ₃Be 100pf, C ₄Be 6.3 μ f, C ₅, C ₆Be 30pf, resistance R ₁Be 58K, R ₂Be 82 Ω, R ₃Be 1.1K, R ₄Be 2K, R ₅Be 3K, R ₆Be 430 Ω, R ₇Be 680 Ω, R ₈Be 45K, be 1/4W, wherein R ₁, R ₄Be adjustable resistance, R ₉Be 4.5K2W, R ₁₀, R ₁₁Be 50 Ω 1W.B is+high-voltage DC power supply of 400V, and adjustable extent is ± 100V, decides with the pipe of selecting for use.

Claims

1, a kind of underground detection radar transmitter by crystal oscillator (1), trigger pip shaping adaptation (2), step voltage generator (3), pulse shaper (4) and bowtie-shaped emitting antenna (5) are formed significantly, is characterized in that: producing degree of stability is 10 ^-6, frequency is that the crystal oscillator (1) of the square-wave signal of 100KHz is by quartz crystal JNB coupling capacitance C ₁With three gate circuit D ₁, D ₂, D ₃And triode G ₁And resistance R ₃The emitter follower that constitutes is formed, and the trigger pip shaping adaptation (2) that obtains 2 μ s 5VE pulses is by capacitor C ₃And resistance R ₅The differentiating circuit that constitutes, two gate circuit D of series connection ₄, D ₅Reach the triode G that signal is divided into two-way ₂And R ₆The emitter follower that constitutes constitutes, the triode G of the input end of trigger pip shaping adaptation (2) and crystal oscillator (1) ₁Emitter be connected, produce at a high speed, the generator of step voltage significantly (3) of transition voltage is by pulse transformer T and avalanche transistor G significantly ₃Constitute, trigger pip shaping adaptation (2) and significantly between the step voltage generator (3) via capacitor C ₄And resistance R ₇The differentiating circuit that constitutes connects, C ₄Meet the triode G of (2) ₂Emitter, R ₇Connect the input end of pulse transformer T, generation ± 150V, the exomonental pulse shaping adaptation of 7ns pulsewidth (4) are by being connected on avalanche transistor G respectively ₃Collector and emitter on two fully symmetry by C ₅And R ₁₀, C ₆And R ₁₁The circuit that constitutes is formed, C ₅And C ₆Respectively with G ₃Collector link to each other with transmitter, the sheet metal that the bowtie-shaped emitting antenna (5) of transponder pulse signal is arranged relatively by the collar point of two identical neck shape structures constitutes, between two sheet metals of the broadside of each knot and be connected with ten identical pull-up resistors of resistance, two input heads by respectively with the resistance R of pulse shaping adaptation (4) ₁₀And R ₁₁The noninductive plug feedback that is connected connects.