Background technology
Active infrared intrsion detector is a kind of detector that is widely used in the circumference safety and protection system, and it normally is made up of an infrared transmitter and an infrared receiving set.Its basic functional principle is: transmitter sends the infrared signal of a branch of or a few bundle through modulating, receiver is received and is made after this signal demodulation constant or other signals that can represent its current state of one of its output give system host, in case the light beam that transmitter sends is interdicted, receiver loses input signal, the signal that its output expression different with original state reported to the police is given system host, main frame is made corresponding processing, realizes warning function.
According to above-mentioned principle, existing active infrared intrsion detector adopts the transmitter 10 that can produce the infrared modulated signal, its structure as shown in Figure 1, the digital coding circuit 11, pulse-code modulation circuit 12, carrier circuit 13 and the infrared emission drive circuit 14 that comprise preface connection successively, infrared emission drive circuit 14 outputs are provided with infrared tube 15, and infrared tube 15 the place aheads are provided with optical focusing system 16.On the carrier wave of certain frequency (the national standard modulating frequency is not less than 400HZ), outwards emission comprises the infrared beam of this modulation signal to this transmitter 10 with the coded modulation of certain sequence.
Receiver and transmitter are oppositely arranged, existing receiver can be divided into two kinds of mode of operations, wherein a kind of is the receiver 20 of employing analog signal work as shown in Figure 2, it comprises the one-level amplifying circuit 21 of preface connection successively, bandwidth-limited circuit 22, second amplifying circuit 23, AC/DC transform integrals circuit 24, threshold circuit 25, and relay drive circuit 26 and alarm signal output circuit 27, wherein 21 liang of inputs of one-level amplifying circuit are provided with back-biased infrared receiving tube 28, one optical focusing system 29 is used for infrared light is focused on infrared receiving tube 28 over against infrared receiving tube 28.The centre frequency of bandwidth-limited circuit 22 is 38KHz.This receiver 20 amplifies modulation signal in one-level amplifying circuit 21, utilize bandwidth-limited circuit 22 to weaken interference, amplify through second amplifying circuit 23 again, through AC/DC transform integrals circuit 24 AC signal is transformed to direct current signal then, this direct current signal compares at a threshold circuit 25 and a comparative voltage, if the voltage of this direct current signal is greater than comparative voltage, then threshold circuit 25 output high level show not invasion.If be blocked because the infrared beam that causes transmitter to send takes place to invade, receiver loses input signal, then threshold circuit 25 output low levels drive the relay contact disconnection in the relay drive circuit 26, make alarm signal output circuit 27 output alarm signals.
Another is a receiver 30 as shown in Figure 3, it comprises preamplifying circuit 31, digital coding demodulator circuit 32, decoding decoding circuit 33 and the relay drive circuit 34 and the alarm signal output circuit 35 of preface connection successively, at 31 liang of inputs of preamplifying circuit back-biased infrared receiving tube 36 is set, and optical focusing system 37 is set in infrared receiving tube 36 the place aheads.This receiver 30 is deciphered carrier (boc) modulated signals through separating to be in harmonious proportion, whether the coded sequence of checking gained is correct, sends intrusion alarm when this encoding stream mistake.
Owing to adopt infrared communication between transmitter and the receiver, so require receiver to take precautions against to make its ineffective technological means (for example with another bundle infrared light irradiation receiver), can resist the interference of strong interferers (for example radar, electric locomotive, transformer, ultra-high-tension power transmission line, microwave station etc.) again and do not produce wrong report.In these areas, the receiver 30 of the receiver 20 of above-mentioned analog operation pattern and digital operation mode respectively has shortcoming.
The receiver 20 of above-mentioned analog operation pattern is owing to be the intensity of judging received signal, therefore the instantaneous interference to strong interferers possesses stronger resistivity, but under the long-time interference of strong interferers, still may produce wrong report, if and with infrared light irradiation receiver 20 of another bundle close frequencies, to make it export high level always and do not send intrusion alarm information, so it almost can't be resisted technological means and cracks system.
The receiver 30 of above-mentioned digital operation mode is owing to be the accuracy of checking coded sequence, and the infrared light of another bundle close frequencies of irradiation receiver is not owing to contain coding, therefore it can be resisted technological means and crack system, but, for the instantaneous interference signal resistivity of strong interferers (as radar, electric locomotive, transformer, ultra-high-tension power transmission line, microwave station etc.) a little less than, the system that makes (was generally 0~2s) and produces wrong report in the moment of disturbing.And when interference source continued, the digital coding demodulator circuit 32 of receiver 30 had from the error correction function, can get rid of interference, no longer wrong report.
The problem that does not possess resistivity at the instantaneous interference signal of 30 pairs of strong interferers of receiver, many people had a go at a lot of the improvement, for example increase the length of coded sequence, perhaps relax the condition of coded sequence accuracy, as long as it is correct that a certain proportion of coded sequence is promptly arranged, promptly think and do not take place to invade, but these improvement all can not satisfactorily resolve this problem.
Summary of the invention
Problem to be solved in the utility model provides a kind ofly can resist instantaneous and long high reject signal, the transmitter and receiver of infrared beam interruption detector that again can the invasion of precautionary technology means.
The utility model is to solve the problems of the technologies described above the technical scheme that adopts to be:
A kind of transmitter of infrared beam interruption detector, comprise the digital coding circuit, pulse-code modulation circuit, carrier circuit and the infrared emission drive circuit that connect in regular turn, this infrared emission drive circuit output is provided with infrared transmitting tube, this infrared transmitting tube the place ahead is provided with optical focusing system, be characterized in, described digital coding circuit produces one first coded sequence and one second coded sequence, and exports two coded sequences to described pulse-code modulation circuit successively.
Described digital coding circuit comprises first group of connecting pin and the second group of connecting pin that connects with predefined connection status, this digital coding circuit produces described first coded sequence according to the connection status of first group of connecting pin, produces described second coded sequence according to the connection status of second group of connecting pin.
Described digital coding circuit also comprises a string line output mouth, in order to export described coded sequence serial to described pulse-code modulation circuit.
The transmitter of described infrared beam interruption detector comprises that also one also comprises a modulating wave output control circuit and a narrow pulse generating circuit, this modulating wave output control circuit is connected between described carrier circuit and the infrared emission drive circuit, with the modulation wave signal of reception carrier circuit and export described infrared emission drive circuit to, this narrow pulse generating circuit is connected this modulating wave output control circuit one input, be used for providing a narrow pulse signal, control the break-make of this modulating wave output control circuit by this narrow pulse signal it.
A kind of receiver of infrared beam interruption detector, comprise a preamplifying circuit, be connected at least one infrared receiving tube of these preamplifying circuit two inputs and infrared light is focused on a optical focusing system on the described infrared receiving tube, also comprise the signal processing channel and drive circuit and the alarm signal output circuit that are connected to the preamplifying circuit output in turn; Be characterized in that described signal processing channel comprises analog signal channel, digital signal passage and output control circuit;
Described analog signal channel comprises one-level amplifying circuit, bandwidth-limited circuit, second amplifying circuit, AC/DC transform integrals circuit and the threshold circuit that is connected to described preamplifying circuit output in turn;
Described digital signal passage comprises:
The digital coding demodulator circuit is connected described preamplifying circuit output, is used for carrier (boc) modulated signals is demodulated to first coded sequence and second coded sequence and the output that is arranged in order;
The decoding decoding circuit, one input end is connected the output of digital coding demodulator circuit, when described first coded sequence and second coded sequence are identical with predefined coded sequence, it exports high level from one first output and one second output simultaneously, otherwise from described first, second output output low level;
Described output control circuit comprises saltus step delay circuit, first AND circuit and OR circuit down; Described down saltus step delay circuit is connected with second output of described decoding decoding circuit, is used for output at described second output by high level during to low transition, makes this saltus step setting-up time of delaying time; Described first AND circuit, one input is connected with following saltus step delay circuit output, another input is connected with the threshold circuit output of described analog signal channel, the output of first AND circuit and OR circuit wherein an input are connected, another input of OR circuit is connected with first output of described decoding decoding circuit, and the output of OR circuit is connected with above-mentioned drive circuit.
In described saltus step delay circuit down, the setting-up time of described time-delay is 1.5~2.5 seconds.
The receiver of described infrared beam interruption detector, wherein, the input of described decoding decoding circuit is a serial input terminal.
Described decoding decoding circuit also comprises first group of connecting pin, and described first group of connecting pin connects with one group of predefined connection status, to produce one group of checking coded sequence of verifying described first coded sequence.
The receiver of described infrared beam interruption detector also comprises one second AND circuit, these second AND circuit, two inputs are connected with described saltus step delay circuit output down with first output of described decoding decoding circuit respectively, and this second AND circuit output is connected with described another input of described OR circuit.
Following brief description detector operation principle:
When receiver receives the infrared modulated signal, its output control circuit output high level;
When the infrared light of above-mentioned transmitter emission was interdicted, the analog signal channel of receiver and digital signal passage be output low level simultaneously, causes the output control circuit output low level, drove the alarm signal output circuit by drive circuit and reported to the police;
When instantaneous interference signal occurring, the anti-instantaneous interference performance of the analog signal channel of receiver makes it still export high level, and above-mentioned following saltus step delay circuit makes second output of digital signal passage keep 1.5~2.5 seconds high level, the two makes first AND circuit keep high level jointly, therefore output control circuit (generally is no more than 1.5 seconds) and keeps high level during disturbing, and prevents wrong report;
When occur such as the infrared light irradiation receiver that utilizes identical wavelength crack means the time, if the infrared light of transmitter emission is blocked, digital signal passage first output output low level immediately then, another output time-delay also output low level after 1.5~2.5 seconds, therefore as long as the infrared light of the transmitter emission time that is blocked surpasses 1.5~2.5 seconds, just occur reporting to the police.
The utility model is by adopting such scheme, combines the two advantage of analog operation pattern and digital operation mode, avoided their shortcomings separately again, improved antijamming capability, effectively prevents to fail to report, report by mistake.
Embodiment
See also Fig. 4, an embodiment of the transmitter 40 of the utility model infrared beam interruption detector comprises digital coding circuit 41, pulse-code modulation circuit 42, carrier circuit 43, modulating wave output control circuit 44, infrared emission drive circuit 45, narrow pulse generating circuit 46, infrared transmitting tube 47, optical focusing system 48.Wherein digital coding circuit 41, pulse-code modulation circuit 42, carrier circuit 43, modulating wave output control circuit 44, infrared emission drive circuit 45 connect successively, narrow pulse generating circuit 46 is connected with modulating wave output control circuit 44, infrared transmitting tube 47 is connected 45 liang of outputs of infrared emission drive circuit, and optical focusing system 48 is arranged on infrared transmitting tube 47 the place aheads.
Digital coding circuit 41 is finished the address to output signal, the coding task of dateout.This digital coding circuit 41 comprises 8 address connecting pin A0~A7,4 data connecting pin D0~D3, and a string line output mouth OUT, every bit address connecting pin and data connecting pin have three states, promptly connect positive source (high level), connect power cathode (low level), vacant state, in the digital coding circuit, represent with 10,00,01 respectively, on behalf of high level, 0,1 represent low level, in detector, these connecting pins can be connected with toggle switch usually, change its connection status by stirring toggle switch.Utilize different addresses, state can be combined into several address codes and numeric data code, digital coding circuit 41 merges address code and numeric data code sequentially, export from serial delivery outlet OUT with serial mode, for example in the present embodiment, address connecting pin A0 connects high level, remaining address connecting pin A1~A7 connects low level, and address code is: 1000000000000000, as first coded sequence of the present utility model; Data connecting pin D0 connects high level, and remainder data connecting pin D1~D3 connects low level, and numeric data code is: 10000000, and as second coded sequence of the present utility model, final serial output 100000000000000010000000.
Pulse-code modulation circuit 42 utilizes the code signal of coding circuit 41 outputs that the carrier signal of carrier circuit 43 is modulated, what adopt in this example is the 38KHZ carrier signal, this signal is produced by carrier circuit 43, modulated carrier signal is loaded into modulating wave output control circuit 44, the burst pulse control modulated carrier signal very little by the duty ratio of narrow pulse generator 46 outputs to infrared emission drive circuit 45, drives infrared transmitting tube 47 by infrared emission drive circuit 45 and sends the modulated infrared light pulse signal of being controlled by burst pulse.The infrared signal that transmitter sends in each burst pulse control cycle is that the carrier frequency that some strings have comprised above-mentioned coded sequence is the infrared modulated ripple of 38KHZ, i.e. some groups 100000000000000010000000 digital infrared signals.
The effect of above-mentioned burst pulse is to make the immediate current of infrared emission drive circuit output very big, be the 70-80% of infrared tube rated current approximately, but its average current is still very little, because infrared tube sends the size that the transmission range of light beam depends on the immediate current of the infrared tube of flowing through, therefore, narrow pulse generator makes the infrared light intensity of the emission of transmitter, operating distance increase greatly, and the also more existing active infrared intrsion detector of antijamming capability is greatly improved.Still in scope of the present utility model, in this another embodiment, but carrier circuit 43 is connected with infrared emission drive circuit 45 another embodiment that does not comprise burst pulse modulation, directly exports through the 38KHz of ovennodulation modulating wave.
In the present embodiment, adopt digital coding circuit 41, pulse-code modulation circuit 42, carrier circuit 43, modulating wave output control circuit 44 incorporate large scale integrated circuits.
See also Fig. 5, output control circuit 56 and relay drive circuit 57 and alarm signal output circuit 58 that an embodiment of the receiver 50 of the utility model infrared beam interruption detector comprises optical focusing system 51, infrared receiving tube 52, preamplifying circuit 53, the digital signal passage 54 that is connected preamplifying circuit 53 outputs, analog signal channel 55, is connected with analog signal channel 55 outputs with digital signal passage 54.
Wherein analog signal channel 55 further comprises one-level amplifying circuit 551, bandwidth-limited circuit 552, second amplifying circuit 553, ac/dc conversion integrating circuit 554, threshold circuit 555, when receiver is received input signal, analog signal channel 55 is by threshold circuit 555 output high level, otherwise, output low level.
Digital signal passage 54 further comprises digital coding demodulator circuit 541 and decoding decoding circuit 542.Digital coding demodulator circuit 541 is connected the output of preamplifying circuit 53, is used for carrier (boc) modulated signals is reduced into geocoding and the encoded data sequence that is arranged in order 100000000000000010000000 for example above-mentioned sequences.Decoding decoding circuit 542 is connected digital coding demodulator circuit 541 outputs, and it comprises a plurality of address connecting pin A0~A7, a plurality of data connecting pin DT0~DT3 and one first output VT.Consistent in the connection status of address connecting pin A0~A7 and the transmitter digital coding circuit, promptly connecting pin A0 connects high level, and other connecting pins A1~A7 connects low level, and to produce one-address code checking sequence, data connecting pin DT0 is as second output.
Output control circuit 56 comprises saltus step delay circuit 561, first AND circuit 562, second AND circuit 563, OR circuit 564 down.The connecting pin DT0 of the decoding decoding circuit 542 in following saltus step delay circuit 561 inputs and the above-mentioned digital signal passage 54 is connected, and output DO is connected with second AND circuit 563 with first AND circuit 562 respectively.First AND circuit, 562 another inputs are connected with the output of the threshold circuit 555 of above-mentioned analog signal channel 55, and the first output VT of the decoding decoding circuit 542 in another input of second AND circuit 563 and the above-mentioned digital signal passage 54 is connected.Output a, the b of two AND circuit is connected with two inputs of OR circuit 564, and the output terminals A LT of OR circuit 564 is connected to alarm signal output circuit 58 as the invasion signal output part through relay drive circuit 57.
Describe the operation principle and the characteristics of receiver in detail below in conjunction with Fig. 5:
The infrared signal that optical focusing system 51 is sent transmitter focuses on the infrared receiving tube 52, and infrared receiving tube 52 converts the infrared signal that receives to faint current signal, and preamplifying circuit 53 is amplified to the needed numerical value of subsequent conditioning circuit with it.After this signal that is exaggerated is divided into two-way, and one the tunnel enters digital signal processing channel 54; Other one the tunnel enters analog passage 55.
At first, enter the modulation signal demodulation that the signal of digital signal processing channel 54 sends transmitter through digital coding demodulator circuit 541 and be reduced into the address code of serial output and the pulse signal of numeric data code combination, export to and decipher decoding circuit 542.The function of decoding decoding circuit 542 is, when the geocoding sequence signal (promptly 1000000000000000) of input and encoded data sequence (promptly 10000000) with its predefined address code, when numeric data code is identical, its first output VT exports high level, the second output DT0 exports the same level of data connecting pin D0 with transmitter, i.e. high level.Following saltus step delay circuit 561 in the output control circuit 56, be used for output at connecting pin DT0 by high level during to low transition, make this saltus step setting-up time of delaying time, specifically, when DT0 is high level, following saltus step delay circuit 561 output DO become high level immediately, and when DT0 was low level, its output DO was a low level; When DT0 became low level by high level, output DO kept high level in a setting-up time, this setting-up time be 1.5~2.5 seconds adjustable, to adapt to different interference environments.This shows that when correct input signal, the output a of second AND circuit 563 is output as high level.
Meanwhile, the signal that enters analog passage 55 is after one-level amplifying circuit 551 amplifies, input to bandwidth-limited circuit 552, bandwidth-limited circuit 552 can be 38KHZ by signal frequency in the present embodiment, the AC signal that is below or above this frequency will be prevented from by, promptly filtered other signals, guaranteed that the signal that transmitter sends enters analog passage 55 reliably.Exporting to second amplifying circuit 553 through the signal of bandwidth-limited circuit filtering 552 amplifies once more to reach the required numerical value of subsequent conditioning circuit, AC signal after will being amplified by ac/dc conversion integrating circuit 554 then is converted to direct voltage, and the power of the signal that this direct voltage and receiver receive is similar in direct ratio.In the present embodiment example, when ac/dc conversion integrating circuit 554 was output as 2.5~4.0V, receiver can be stablized, work reliably.Threshold circuit 555 is voltage comparator circuits, and its operation principle is, when its input voltage was higher than comparative voltage (being threshold voltage), the output MT of threshold circuit 555 was a high level, on the contrary output low level.In the present embodiment, the comparative voltage of threshold circuit is set in 1.8V.Change this comparative voltage, the time that can make blocking produce warning changes.
When receiver stably receives signal, and the direct voltage of ac/dc conversion integrating circuit 555 outputs is during greater than 1.8V, and the output b of first AND circuit 562 also is the output high level.This shows, as long as receiver normally receives signal, the output a of two AND circuit, b two ends all are high level, through OR circuit 564, because the effect of OR circuit 564, as long as any end of a, b is a high level, the output terminals A LT of OR circuit is a high level, make the normally-closed contact adhesive of relay through relay drive circuit 61, i.e. detector be on the alert (promptly not invading state).
When the signal of transmitter 40 is interdicted, digital signal processing channel 54 has lost input signal, decoding decoding circuit 542 can't translate signal, thereby, first, second output VT, DT0 are low level simultaneously, although following saltus step delay circuit 561 output DO will keep the high level of certain hour this moment, the output a end of second AND circuit 563 will become low level; Meanwhile, analog passage 55 does not have the signal input yet, the direct voltage of ac/dc conversion integrating circuit 554 outputs becomes 0V rapidly and is lower than 1.8V, the output MT output low level of threshold circuit 555, thereby, the output b end output low level of first AND circuit 562, at this moment, the output terminals A LT of OR circuit 564 becomes low level, thereby relay drive circuit 61 no driving voltages are exported, the normally-closed contact of relay discharges, and exports switching value (broken string) alarm signal, finishes the warning function of detector.
As high reject signal (as the instantaneous interference of radar, electric locomotive, transformer, ultra-high-tension power transmission line, microwave station etc.) when sealing in preamplifying circuit 53, the interference signal that seal in this moment might cause digital coding demodulator circuit 541 can't demodulate the modulation signal that transmitter sends moment, thereby decoding decoding circuit 542 first output VT, the second output DT0 become low level, at this moment, the output a of second AND circuit is a low level; For high reject signal, because the effect of the bandwidth-limited circuit 552 in the analog signal channel 55, have only frequency to enter analog passage 55 near the interference signal of 38KHZ, this interference signal can be superimposed upon on the signal that transmitter that receiver receives sends, therefore, the direct voltage of ac/dc conversion integrating circuit 554 outputs will rise, and be higher than the comparative voltage (being threshold voltage) of threshold circuit 555 far away, and the output MT of threshold circuit will keep the output high level.Although this moment, the DT0 end was low level, owing to the effect of saltus step delay circuit 561 down, its output DO will keep the high level of certain hour (1.5~2.5 seconds), two input MT, the DO of first AND circuit 562 end is high level simultaneously in this setting-up time so, therefore, the output b of first AND circuit 562 is output as high level, the output ALT of OR circuit 564 is a high level, thereby relay drive circuit 61 is kept normally closed some adhesive of relay, detector maintains the state of alert, and promptly high reject signal can not make detector produce alarm signal.Generally, it is very little to continue the above strongly disturbing situation of 1.5s, simultaneously, because digital coding demodulator circuit 541 has autonomous error correction, therefore, high reject signal can only produce the interference of moment to it, and the effect of analog passage 55 and following saltus step delay circuit 561 has remedied this defective of digital coding demodulator circuit 541, makes the antijamming capability of detector improve greatly.
For existing digital coding active infrared intrsion detector, more insoluble problem is the interference that the homogenous frequency signal from other transmitters causes, and the utility model adopts the receiver of analog signal channel 55 and digital signal passage 54 just can address this problem well simultaneously.If the homogenous frequency signal from other transmitters is regarded as interference signal, its anti-interference principle is just basic identical with foregoing, and promptly analog signal channel 55 can be resisted this interference.
In addition, receiver 50 of the present utility model has the technological means of resisting and cracks system capability.When being radiated on the receiver of the utility model active infrared intrsion detector with the infrared lamp of wavelength at 800-940nm, attempt blocking infrared light and when passing warning region, if the signal time that the blocking transmitter sends is greater than the setting delay time (1.5~2.5 seconds) of following saltus step delay circuit 561, the output DO of following saltus step delay circuit 561 becomes low level, output a, the b of two AND circuit become low level simultaneously, the normally closed point of relay discharges, and detector will send the alarm signal of switching value (broken string).Suitably regulate the delay time of saltus step delay circuit 561 down, both can make detector have stronger antijamming capability, reduce rate of false alarm, can prevent to fail to report the possibility of the system that cracks with the application technology means again.
In the present embodiment, second AND circuit 563 can be omitted need not, the first output VT end of decoding decoding circuit 542 directly links to each other with the input a end of OR circuit and gets final product, function is basic identical, but, the effect of second AND circuit 563 is to make the synchronism of analog signal and digital signal output better, relatively near consistent.Yet no matter whether receiver comprises second AND circuit, all in the utility model scope.
Therefore, the utility model active infrared intrsion detector had both had existing digital active infrared intrsion detector, the whole advantages of simulation active infrared intrsion detector, having overcome their shortcoming again respectively, is a kind of excellent performance, the extremely strong active infrared intrsion detector of anti-interference.