Guard against theft and alarm system
The present invention relates to a kind of guard against theft and alarm system, relate in particular to the impulse disturbances restraining device of system.
At present, utilize the guard against theft and alarm system of formations such as infrared sensor, ccd image sensor and sonac or install variedly, they all have certain effect in scope separately.But, in practicality, also exist some problems:
1. cost height, conventional unit and general resident are difficult to bear economically;
2. be subjected to the influence of various factors, often malfunction or tripping, reliability is not high;
3. need adopt dedicated line or wireless transmit mode transmission signals, this way one is to increase cost, the 2nd, and circuit suffers offender's destruction easily.Wireless transmission mode wherein, through-put power is restricted, and forms when reaching certain power when disturbing, and should handle the Shen to radio control department and criticize formality.
Because exist above problem, present guard against theft and alarm system has been subjected to certain limitation aspect applying.
Goal of the invention of the present invention is exactly the problem and shortage at above-mentioned existence, and a kind of ratio of performance to price height of developing, can effectively suppress to disturb and guard against theft and alarm system that reliability is high, it not only can be used for general private residence, and can be used for megastore, office building, warehouse and financial security department etc.
Goal of the invention of the present invention is achieved in that
1. system forms: mainly be made up of user's contact sensor (JDCG), alerting signal monitoring device, area monitoring device and main control microcomputer.Wherein the contact sensor places user's door lock, window or indoor guard key position; The alerting signal monitoring device also places user's indoor (because volume is small and exquisite, also can be used as a kind of ornament), and the area monitoring device is placed in Property Management of residence division office or duty room, and main control microcomputer is arranged on local local police station.
2. signal transmission form: the alerting signal monitoring device adopts low voltage electric power carrier communication with communicating by letter of area monitoring device; Decide on the distance of communication distance between area monitoring device and the main control microcomputer, can adopt low voltage electric power carrier communication or telephone line communication mode.
3. principle of work: when the offender illegally when door or window enter, the action of contact sensor, connect the alerting signal monitoring device, the coded signal that single-chip microcomputer in this device produces the user automatically and distributed, this coded signal is after modulation is amplified, send to low-tension network, transfer to the area monitoring device through power circuit; The area monitoring device carries out frequency-selecting amplification, demodulation, shaping amplification to the coded signal of being received, sends into single-chip microcomputer through interface circuit; After single-chip microcomputer is handled this coded signal, coded signal is translated into user's house number (or place), show, send sound and light alarm simultaneously, the prompting operator on duty, the operator on duty can arrive in the incident user rapidly according to the house number (or place) that shows.In addition, the area monitoring device main control microcomputer that also alerting signal sent to local local police station is reported to the police.
4. gordian technique: in this scheme of enforcement, wherein gordian technique is a low voltage electric power carrier communication line transmission signals and anti-interference.Communicating by letter between user and the cell management department need do not laid dedicated line, and adopts low voltage electric power carrier communication.We know that low-voltage power line is because its load character complexity has refrigerator, colour TV, various forms of daylight lamp, electricity-saving lamp and motor etc., and its interference is very serious.Currently used interference protection measure can not solve the problem that signal disturbs.For this reason, we have carried out a large amount of theoretical researches and test, comprise the analysis of the communication frequency and the interference waveform of low-voltage power line.Through studying repeatedly and testing, the carrier frequency of determining the low-voltage power carrier line is 85kHz~90kHz.Owing to disturb based on impulse disturbances, to this impulse disturbances mode, existing method is powerless, and according to research and test findings, we have designed a kind of " impulse disturbances restraining device ", thereby problem is readily solved.
This guard against theft and alarm system has the following advantages:
1. antijamming capability is strong, and is stable and reliable for performance, can not make a mistake and report to the police or do not report to the police.
2. alarm velocity is fast, in case take place unusually, the operator on duty just can obtain information in 1 second, take action rapidly.
3. easy to install, only need that the alerting signal monitoring device is inserted 220 volts of power supplys and can enter system.
4. cost is low, is easy to promote.
Describe in detail below in conjunction with accompanying drawing.
Fig. 1 is the native system composition frame chart, wherein: 1-JDCG (user's contact sensor), 2-alerting signal monitoring device, 3-area monitoring device, 4-master's control microcomputer, 5-power line carrier, PLC line, 6-telephone wire, the dried restraining device of scratching of 7-pulse.
Fig. 2 is this impulse disturbances restraining device composition frame chart.
Fig. 3 is this impulse disturbances restraining device wave form analysis figure.
Fig. 4 is this impulse disturbances restraining device circuit theory diagrams.
Wherein: 8-trap wave unit, 9-integral unit I, 10-and door, 11-integral unit II, 12-or door, 13-signal restoring unit, V
i-input signal, V
0-output signal, W
1.W
2-adjustable resistance, T
gThe width of-disturbing pulse, T
x-time constant.
As shown in Figure 1, native system is made up of user's contact sensor (JDCG) 1, alerting signal monitoring device 2 and area monitoring device 3 and main control microcomputer 4; User's contact sensor (JDCG) 1 and alerting signal monitoring device 2 are electrically connected mutually, alerting signal monitoring device 2 is connected by power line carrier, PLC line 5 with area monitoring device 3, and area monitoring device 3 is connected by telephone wire 6 or power line carrier, PLC line 5 with main control microcomputer 4.Serial connection impulse disturbances restraining device 7 on power line carrier, PLC line 5.
As shown in Figure 2, this impulse disturbances restraining device mainly is made up of the following units, its annexation is: the input end of trap wave unit 8 and integral unit I 9 interconnects a point, as the input end of this device 7, the output terminal of trap wave unit 8, integral unit I 9 connects input end b, the c with door 10 respectively; The input end of integral unit II 11 and signal restoring unit 13 is interconnected in the output terminal d point with door 10 again, its output terminal respectively with or the input end of door 12 be connected.
The effect of trap wave unit 8 is that input signal (no matter being useful signal or noise spike undesired signal) is suppressed a part (generally getting 1/2~2/3 pulse signal width).Integral unit I 9 has two effects, and one can be eliminated the narrower spike pulse of general width; Its two, prevent that the bursts of error that take a risk to produce because of sequential competition from disturbing.Signal restoring unit 13 is recovered the input signal that trap wave unit 8 curbs or is restored.The effect of integral unit II 11 is continuous ripples, and the signal waveform after guaranteeing to recover produces distortion continuously and not.
This impulse disturbances restraining device principle of work is analyzed in conjunction with the oscillogram of Fig. 3.The a point meets input waveform V
i, arrive input end b after a passing point unit 19 delayed slightly with door 10; Another road is through trap wave unit 8, as input waveform V
iWhen arrive in last jumping edge, producing a time width is T
xLow level, will block input signal V with door 10
iCan't be by entering next stage with door 10.Elapsed time T
xAfter, trap wave unit 8 recovers high level, input signal V
iBy entering next stage with door 10, the waveform that d is ordered is suppressed a time width T exactly
xAfter input signal V
i(d), signal V
i(d) also be divided into two-way, a passing point unit II 11 arrives or door 12 and exporting, and another road connects the input end of signal restoring unit.As signal V
iWhen arrive in following jumping edge (d), trigger pip restoration unit 13, producing a width by the former unit 13 of signal is T
xPulse, cooperate continuous ripple with integral unit II 11, the signal section that trap wave unit 11 is curbed recovers, thereby the input signal after must restoring.By oscillogram as seen, V
i(a) and V
0(f) waveform is in full accord, just in time the latter than the former stagnant a back time T enough
xOn oscillogram, also can find out, when accompanying impulse disturbances in the input signal, because its width T
gThan signal pulse width T
xFor a short time, (, make T by selecting the trap time constant of suitable trap wave unit 8
x>T
g), then the low level that is produced by trap wave unit 8 is blocked and door 10, makes it to reach next stage and produces output, thereby reach the purpose that suppressor pulse disturbs.
The characteristics of this pulse interference suppression device:
1. to the various impulse disturbances that seal in the signal, as long as disturbing pulse width TgBe lower than signal pulse width Tx, all can be fully suppressed, thus the reliability of signal transmission greatly improved;
2. effectively solved the key technology of low-voltage power network power carrier, i.e. various impulse disturbances Problem;
3. this device not only can be used for power line carrier, PLC, and can be used for other communication system;
4. circuit structure is simple, and debugging is convenient, the reliability height, and cost is low;
5. technique effect: the guard against theft and alarm system antijamming capability that the pulse interference suppression device is housed is strong, its Rate of false alarm drops to 0.1% by original 10%.