Abstract: Introduced one kind based on the telephone network video frequency alarm system’s design proposal, this plan traditional alarm system and video frequency supervisory system organic synthesis, not only has realized the warning basic function, moreover may transmit the scene information through the video frequency system, with the aim of keeping abreast of the scene situation rapidly, judges accurately whether to have the police sentiment occurrence.
Key word: 80C196NP video frequency alarm system
At present the domestic and foreign alarm system, selects the telephone call method. After warning triggering, according to warning type dial predetermined telephone number, but because cannot prompt accurate obtain the warning scene the real information, easy to create the false warning the occurrence, thus has hindered this kind of systematic promoted application.
In order to solve based on the telephone network video frequency alarm system which tradition alarm system these flaws develop, it organically unifies the traditional alarm system and the video frequency supervisory system, not only has the tradition alarm system’s basic function, moreover may gather the scene information through the video frequency system, and transmits through the telephone network to the monitoring center, thus may judge accurately whether to have the police sentiment occurrence.
1 System principle of work and performance index
The system takes the data transmission network by the public telephone network, the warning monitoring point through the wireless alarm device gathering alarm message, after entering the defended condition, any detector is triggered, examines the signal and after the decoding through the wireless launch receive module, controls the warning process by the monolithic integrated circuit. First dials by the automatic dialing electric circuit answers alarm the number and starts the supervisory system, after treating answers alarm, the system automatically the scene video data passes on to the monitoring center, with the aim of keeping abreast of the scene situation rapidly, reduces, because each kind of reason creates harms the triggering warning.
This system uses the multi-channel sensing connections, integrated the community alarm system’s major function, the use tetherless access wired telephone network warning way, realizes the auto-alarm, uses the advanced video frequency transmission technology, has realized the scene monitoring. Overall performance index:
(1) Saves 16 groups of telephones, the handset or the pager numbers, when the warning automatic circulates according to sequence dials calls.
(2) Has the wireless gate magnetism, the wireless infrared acquisition aid, the wired intrusion detector standard interface.
(3) Has the first warning, the telephone outwire against to cut functions and so on warning, remote control triggering urgent warning, colony networking warning.
(4) Connection characteristic: Observed as.
(5) Maximum transmission speed: 33.6kbps.
(6) Maximum phantom transmission speed: 15fps.
(7) Mode of transmission: Synchronous mode.
(8) Video frequency connection time: 15-20s.
2 The system hardware design with realizes
2.1 system hardware architecture
The system hardware takes the control center by the 80C196NP monolithic integrated circuit, mainly by the master control module, the video frequency gathering compression transmission module, the signal detection module, the wireless launch receive module and so on is composed. System structure as shown in Figure 1.
2.2 master control modules
The system master control part uses high performance l6 which Intel Corporation produces position monolithic integrated circuit 80Cl96NP, this chip has the 1M addressing ability, and works under the 25MHz crystal oscillator, has the quick working speed. The watch-dog electric circuit uses American Xicor Corporation’s X25045, it the voltage monitoring, the watch-dog timer and the EEPROM combination in the single chip, its volume is young, and takes the I/O mouth to be few. X25045 including 512*8 position serial EEPROM, may with the micro controller’s I/O mouth serial docking, use in saving the telephone number and the system establishment data directly and so on, among them has a units place instruction register, this register may visit through S1. If does not have main line’s activity in the watch-dog timer pre-placed overtime time, then X25O45 will output the reset signal. P1 mouth achievement wireless infrared and alarm and so on wireless gate magnetism input ports.
2.3 video frequency gathering compression transmission module
Because can only realize the data transmission through the modem, the image data must pass through the great proportion the compression, uses the highly effective graph packed format. This system chooses the JPEG form. The camera output simulation composite video signal, arranges/decoder SAA7111 by the video frequency to carry on the chroma separation and A/D to it transforms, the output digit video signal and the clock signal, the good field synchronizing signal and the odd and even field pilot signal, enters JPEG to arrange decoding chip ZR36060. Arranges the decoding chip the synchronized signal sampling which and with it synchronization outputs to the video frequency decoder, the simultaneous reception digital video signal and carries on the compression to it, will compress after again the JPEG form’s image data reads in SRAM, controls these data by the monolithic integrated circuit, after general asynchronous transmission receiver 16C550 serial, transmits through the modem to the monitoring center.
2.4 signal detection module
Regarding calling, in dials telephones in the number process, possibly meets the telecommunication signal includes: Dial tone, busy signal and ring-back tone. These signal’s characteristic is:
(1) dial tone: 450Hz monofrequent continuously.
(2) busy signal: 450Hz monofrequent, 0.35s equal-space off and on.
(3) ring-back tone: 450Hz monofrequent, 1s continues 4s to break.
May see from 3 signal’s characteristics, their frequency is the same, the make-and-break time is different. According to monolithic integrated circuit’s need, by the outwire the modulation signal which comes after the capacitive coupling must after detection processing. The electric circuit completes the demodulation process by the NE567 audio frequency phase-locked loop. NE567 internal quadrature phasing detector comparison input signal and current control oscillator signal frequency and phase, when the input signal falls when the allocated frequency band, the signal is locked, 8 feet output the low level. Internal neterodyne frequency f may through the RC hypothesis. Namely f= 1/1.1RC. The telephone carrier frequency is 450Hz, R usually in 2KΩ~20KΩ in the value, if R takes 20KΩ, calculates C=0.1pF. After center frequency determination, the electric circuit key-in obtains by the equation below:
Vi for the input signal effective value, requests not to be bigger than when 200mV, C takes 0.1pF, may satisfy the telephone signal carrier frequency the request.
Will possess the signal in the system to draw out from telephone interface circuit identical spot, uses for after the NE567 phase-locked loop electric circuit to determine that in the line whether there is the 450Hz tonic train signaling, and does output the height level duration different signal impulse, then does not come together by the monolithic integrated circuit using the height level duration distinguishes these telecommunication signal.
2.5 wireless launch receive module
Are bad as a result of the general LC oscillator frequency stability and the uniformity, even if uses the high quality the trimming electric capacity, the temperature difference change and the vibration are also very difficult to guarantee that already adjusted good frequency not to have the displacement, therefore has used the launch module in this design (F05) and the receive module (J01E), the F05 series uses the sound surface resonator steady frequency. The SMT resin package, the frequency uniformity is good, exempts the debugging. F05 has the wide working voltage scope and the low power loss characteristic. When the launch voltage is 3V, the emission current 2mA, the emissive power is approximately small. 12V is the best working voltage, has the good launch effect, the emission current is 5~8mA. The F05 series will use the AM way modulation by to lower the power loss, the data signal stops, the emission current will reduce to zero.
J01E uses the unique super regenerative circuit structure, the SMT craft resin package, the content enlargement reshaping, the output data directly to the decoder, the use great convenience, is one kind of performance-to-price ratio good ultra regeneration module. J01E does not have when the signal outputs the zero level condition (non-noise jamming) to be possible to suit in the monolithic integrated circuit input end connection. J01E has the wide receive band width, has the low power loss, when 3V only consumes 0.2mA the electric current, may be at for a long time defends machine the condition.
In order to enhance system’s reliability and the secrecy, has used PT2262, PT2272. PT2262 is codes the module, PT2272 decodes the module. Code chip PT2262 sends out the coded signal by the address, the data code, the synchronous code is composed, after decoding chip PT2272 receives the signal, must carry on two checkups to the address, if with own address match, the VT pin outputs the high level, simultaneously the corresponding data foot also outputs the high level. PT2272 through D0~D3 four data pin connection master control module P1.4~P1.7 pin to main engine transmission data, when alarm free these four P1 pin’s input is 0. After the main engine starts, will monitor these four P1 pin throughout, discovered the input will not be when 0 will explain the warning occurrence, and according to them the current value to determine the warning source.
3 The system software design with realizes
3.1 master routine parts
Master routine flow as shown in Figure 3, the system may accept from the main engine or the remote control pressed key order enters separately withdraws from a defended position and garrisons the condition, withdraws from a defended position under the condition function operation is mainly the telephone number input, and may accept the main engine or the remote control pressed key signal enters the defended condition. In deploys troops for defense under the condition, 80C196NP scans the P1 mouth to judge unceasingly whether to have the police sentiment occurrence, if has the police sentiment to start the warning subroutine as well as the video frequency monitoring subroutine.
The system initialization including the interrupt establishment, the X25045 memory block bestows on the starting value, the data acquisition module initialization and so on, will adopt the inquiry way to the main engine keyboard’s response and carries on time delay processing, the system will carry on the interrupt response warning by INT1.
3.2 video data processing submodule
Video data processing flow as shown in Figure 4, the initialization mainly completes receives and transmits channel’s initialization, the memory region division, fixed time the clock and the counter reset either the starting value establishment, the interrupt closure or the opening, the specified data in the transmission time block form, the image data reference and the size and so on. After the system completes the initialization, the start graphic data gathering module, starts to gather an image, through writes the address and writes a letter the number the data storage to SRAM. When gathering ended, gathering symbolized the signal rescission, 80C196NP starts to read in SRAM the image data, the data outputs the serial data after SC16C550, and through the Modem transmission to receiving end. After data end of transmission, start next data acquisition.
3.3 alert control submodule
This system’s warning scanning selects the port scanning method, carries on to the P1 mouth scans unceasingly, when presents the police sentiment, after passing through certain time delay, then carries on the scanning, if still had the alarm to enter picks on-hook processing segment.
For the convenience programming, the telephone number which saves in X25045 takes group of numbers by F0H the start to symbolize, FFH artificially for complete number end mark. The alarm system by stores the number the flag bit to decide that picks machine, the digit dialing and the start video frequency monitoring, after picking machine, the time delay 2 seconds start the digit dialing, each digit dialing 0.1s, after dialing, time delay 0.1s. After dialing a group of telephone number waits for 2 s, starts to start the video frequency monitoring subroutine. Alert control subroutine flow as shown in Figure 5.
4 Conclusion
Through the above software and hardware design proposal and the user service condition investigation, this system has the following superiority:
(1) the system takes the transmission medium by the public telephone network, conforms to the national public telephone network signaling standard, does not need the independent wiring;
(2) the economy is durable, selects the method which the software and hardware unifies, is advantageous for the expansion promotion;
(3) as a result of the integration telephone call and the video frequency transmission, has solved the system misinformation problem well;
Because this system is designs the research and development in the mechanics of communication and in the multimedia technologies union foundation, will also receive the communication network condition in systems operation’s process the influence, because the band width will be narrow, the video frequency transmission will receive certain limit, the speed is slow, but regarding will keep abreast of the scene situation, the discrimination warning type basic has been able to satisfy the request.
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He Limin. The monolithic integrated circuit application system designs the [M]. Beijing: Beijing University of Aeronautics and Astronautics Publishing house .1994
