CN102025413A - Infrared receiving circuit - Google Patents
Infrared receiving circuit Download PDFInfo
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- CN102025413A CN102025413A CN2009101904411A CN200910190441A CN102025413A CN 102025413 A CN102025413 A CN 102025413A CN 2009101904411 A CN2009101904411 A CN 2009101904411A CN 200910190441 A CN200910190441 A CN 200910190441A CN 102025413 A CN102025413 A CN 102025413A
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- remote receiver
- high level
- receiving circuit
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Abstract
The invention relates to an infrared receiving circuit comprising an infrared receiver, a singlechip and an integrating circuit connected between the infrared receiver and the singlechip, wherein the integrating circuit comprises a resistor and a capacitor; the resistance of the resistor is R; the capacitance of the capacitor is C; the resistor is connected between a signal output end of the infrared receiver and the input end of the singlechip; the capacitor is connected between the input end of the singlechip and the ground; and the time constant R*C of the integrating circuit is greater than the time of high-level interference pulse. By implementing the technical scheme of the invention, the capacitor of the integrating circuit slowly discharges when the infrared receiver receives a signal; and the discharge of the capacitor can be maintained to the arrival of high level, so that the interference pulse of the high level can be filtered and the singlechip is free from responding to the interference pulse, thereby playing a role of resisting interference.
Description
Technical field
The present invention relates to a kind of infrared receiving circuit, more particularly, relate to a kind of jamproof infrared receiving circuit.
Background technology
Infrared communication is to utilize the medium of the infrared ray of 950nm near infrared band as the information of transmission, transmitting terminal adopts pulse-time modulation (PPM) mode, binary digital signal is modulated into the pulse train of a certain frequency, and drive infrared transmitting tube and send with the form of light pulse, receiving terminal converts the light pulse that receives to the signal of telecommunication, carry out demodulation through giving demodulator circuit after the processing such as amplification, filtering again, be reduced to binary digital signal output.In brief, the essence of infrared communication is carried out modulation to binary digital signal exactly, so that utilize infrared channel to transmit, the infrared communication interface is exactly the modulator-demodulator to infrared channel.
Infrared transtation mission circuit has two and selects modulation synchronously and asynchronous signal automatically according to coded format, will form a synchronous/asynchronous modulation after pulse signal/modulation signal mutual superposition; Infrared receiving circuit comprises preposition amplification, amplitude limit amplification, bandpass filtering, separated in synchronization, peak detection, enable detection and waveform shaping, thereby demodulates and import the remote control pulse and the enable signal of remote signal homophase.
Fig. 1 is the circuit theory diagrams of infrared receiving circuit in the prior art, this infrared receiving circuit comprises infrared remote receiver H1, single-chip microcomputer U1, wherein, the pin 1 (Vcc) of infrared remote receiver H1 connects high level by resistance R 2, its pin 2 (GND) ground connection, its pin 3 (signal output part) connects the pin 14 of single-chip microcomputer.When infrared remote receiver H1 when not receiving the infrared signal that the infrared transmitter (not shown) launched, its pin 3 output high level, the pin 14 of single-chip microcomputer U1 receives high level; When infrared remote receiver H1 when receiving infrared signal, the high level of its pin 3 outputs is dragged down, the pin 14 of single-chip microcomputer U1 receives low level.
For the infrared emission receiving circuit, electromagnetic interference is inevitable thing, under disturbing misoperation usually takes place.Shown in Fig. 2 A, 2B, the waveform schematic diagram that transmits when Fig. 2 A is subjected to electromagnetic interference, Fig. 2 B is the waveform schematic diagram of corresponding with Fig. 2 A received signal when being subjected to electromagnetic interference, dash area 1 is an interference, the corresponding high level of interference that constantly just produces of Fig. 2 B, the pin 3 of infrared remote receiver will correspondingly be exported a high level, and this high level of interference is transferred into the pin 14 of single-chip microcomputer U1, thereby makes single-chip microcomputer produce misoperation.
Summary of the invention
The technical problem to be solved in the present invention is, at the not anti-interference defective of the above-mentioned infrared receiving circuit of prior art, provides a kind of jamproof infrared receiving circuit.
The technical solution adopted for the present invention to solve the technical problems is: construct a kind of infrared receiving circuit, comprise infrared remote receiver and single-chip microcomputer, also comprise the integrating circuit that is connected between infrared remote receiver and the single-chip microcomputer, described integrating circuit comprises resistance and electric capacity, the resistance of described resistance is R, and the capacitance of described electric capacity is C;
Described resistance is connected between the input of the signal output part of infrared remote receiver and single-chip microcomputer, and described electric capacity is connected between the input and ground of single-chip microcomputer;
Described integration circuit time constant R * C is greater than the time of high level of interference pulse.
In infrared receiving circuit of the present invention, the capacitance C of the frequency F of high level of interference pulse and electric capacity and the resistance value R of resistance satisfy following relationship:
C＝1/2RFπ
Wherein, π is a circumference ratio.
In infrared receiving circuit of the present invention, the resistance R of described resistance is 10k Ω.
In infrared receiving circuit of the present invention, also comprise current-limiting resistance, the power end of described infrared remote receiver connects high level by described current-limiting resistance.
In infrared receiving circuit of the present invention, also comprise isolation capacitance, the earth terminal ground connection of described infrared remote receiver, described isolation capacitance is connected between the power end and earth terminal of described infrared remote receiver.
Implement infrared receiving circuit of the present invention, has following beneficial effect: when the infrared remote receiver received signal, the electric capacity of integrating circuit slowly discharges, because capacitance discharges can be maintained to the arrival of next high level, therefore the disturbing pulse of high level can be filtered, make single-chip microcomputer not respond disturbing pulse, thereby play jamproof effect.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples, in the accompanying drawing:
Fig. 1 is the circuit theory diagrams of infrared receiving circuit in the prior art;
Fig. 2 A is the waveform schematic diagram that transmits when being subjected to electromagnetic interference;
Fig. 2 B is the waveform schematic diagram of corresponding with Fig. 2 A received signal when being subjected to electromagnetic interference;
Fig. 3 is the circuit theory diagrams of infrared receiving circuit embodiment one of the present invention;
Fig. 4 A is when interference signal occurring, integrating circuit input voltage waveform schematic diagram;
Fig. 4 B is when interference signal appears in Fig. 4 A, integrating circuit output voltage waveforms schematic diagram.
Embodiment
As shown in Figure 1, in the circuit diagram of infrared receiving circuit embodiment one of the present invention, in this circuit diagram, comprise infrared remote receiver H1, single-chip microcomputer U1, resistance R 2, capacitor C 2 and be connected single-chip microcomputer and infrared remote receiver between integrating circuit, wherein, described integrating circuit comprises resistance R 1 and capacitor C 1, the resistance of resistance R 1 is R, the capacitance of capacitor C 1 is C, resistance R 1 is connected between the pin 14 (input) of the pin 3 (signal output part) of infrared remote receiver H1 and single-chip microcomputer U1, capacitor C 1 is connected between the pin 14 and ground of single-chip microcomputer U1, the pin 1 (Vcc) of infrared remote receiver H1 connects high level by resistance R 2, its pin 2 (GND) ground connection, capacitor C 2 are connected between the pin 1 and pin 2 of infrared remote receiver H1, play buffer action.The pin 20 (Vcc) of single-chip microcomputer U1 connects high level, its pin 10 (GND) ground connection, and its pin 15 (output) can connect the control appliance (not shown), as light fixture etc.
Infrared remote receiver H1 is not when receiving infrared signal, its pin 3 output high level, signal is sent to the pin 14 of single-chip microcomputer U1 by resistance R 1, capacitor C 1, and the pin 14 of single-chip microcomputer U1 is judged and do not received infrared signal according to receiving high level, thereby do not do corresponding action; When infrared remote receiver H1 when receiving infrared signal, its pin 3 output low levels, signal is sent to the pin 14 of single-chip microcomputer U1 by resistance R 1, capacitor C 1, the pin 14 of single-chip microcomputer is judged and is received infrared signal according to receiving low level, thereby makes corresponding action.
The operation principle of the infrared receiving circuit of following mask body introduction band integrating circuit, shown in Fig. 4 A, 4B, Fig. 4 A is when interference signal occurring, integrating circuit input voltage waveform schematic diagram, Fig. 4 B is when interference signal appears in Fig. 4 A, and integrating circuit output voltage waveforms schematic diagram at first need to prove, the input voltage of integrating circuit is the output voltage of infrared remote receiver H1 pin 3, and the output voltage of integrating circuit is the input voltage of the pin 14 of single-chip microcomputer U1.At t=0 to t1 constantly, infrared remote receiver H1 does not receive infrared signal, its pin 3 output high level, i.e. input voltage U of integrating circuit
iBe high level, because of the charging of the capacitor C 1 of integrating circuit is finished, so the output voltage U of integrating circuit
oBe high level.When t1 arrived constantly, infrared remote receiver H1 began to receive infrared signal, its pin 3 beginning output low level, i.e. input voltage U of integrating circuit
iBe low level, because of the voltage of the capacitor C 1 of integrating circuit can not suddenly change, therefore, and at t1 constantly, the voltage at electric capacity two ends, the i.e. output voltage U of integrating circuit
oIt still is high level.During t1 to t2, capacitor C 1 becomes inverse electromotive force, and beginning is to resistance R 1 discharge, the voltage at capacitor C 1 two ends, the i.e. output voltage U of integrating circuit
oBegin to be exponential decrease, be low level.In the time of during high level of interference pulse 1 appears at t2 to t3, capacitor C 1 begins charging, the voltage at its two ends, the i.e. output voltage U of integrating circuit again
oBe exponential increasing, because integration circuit time constant R * C is greater than the duration of high level of interference pulse 1, therefore, moment t3 in high level of interference pulse 1 end, the charging of capacitor C 1 still can not be finished, the magnitude of voltage that is capacitor C 1 two ends still is lower than high level, i.e. the output voltage U of integrating circuit
oBe low level, therefore having added the infrared receiving circuit behind the integrating circuit can filter the High-frequency Interference pulse.
Subsequently, during t3 to t4, high level of interference pulse 1 disappears, infrared remote receiver H1 continues to receive infrared signal, its pin 3 output low levels, promptly the input voltage Ui of integrating circuit is a low level, the capacitor C 1 in the integrating circuit is restarted discharge on the basis of the moment t3 that charging finishes, at this moment, the output voltage U of integrating circuit
oBe lower than high level, promptly the voltage that receives of single-chip microcomputer U1 is low level always, and single-chip microcomputer U1 can judge according to the input voltage signal of its pin 14 receive infrared signal, thereby makes corresponding action.After the moment, infrared remote receiver H1 stops to receive infrared signal at t4, its pin 3 output high level, i.e. input voltage U of integrating circuit
iBe high level, the capacitor C 1 in the integrating circuit begins charging on the basis of the moment t4 that discharge finishes, at this moment, and the output voltage U of integrating circuit
oBe exponential increasing, up to arriving high level, single-chip microcomputer U1 can not receive infrared signal according to the input voltage signal judgement of its pin 14, thereby makes corresponding action.
Preferably, the frequency F of the resistance R of the resistance R 1 of integrating circuit and the capacitance C of capacitor C 1 and High-frequency Interference pulse satisfies: C=1/2RF π, wherein, π is a circumference ratio.
The preferred 10k Ω of the resistance of resistance R 1.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within the claim scope of the present invention.
Claims (5)
1. an infrared receiving circuit comprises infrared remote receiver and single-chip microcomputer, it is characterized in that, also comprise the integrating circuit that is connected between infrared remote receiver and the single-chip microcomputer, described integrating circuit comprises resistance and electric capacity, and the resistance of described resistance is R, and the capacitance of described electric capacity is C;
Described resistance is connected between the input of the signal output part of infrared remote receiver and single-chip microcomputer, and described electric capacity is connected between the input and ground of single-chip microcomputer;
Described integration circuit time constant R * C is greater than the time of high level of interference pulse.
2. infrared receiving circuit according to claim 1 is characterized in that, the capacitance C of the frequency F of high level of interference pulse and electric capacity and the resistance value R of resistance satisfy following relationship:
C＝1/2RFπ
Wherein, π is a circumference ratio.
3. infrared receiving circuit according to claim 2 is characterized in that, the resistance R of described resistance is 10k Ω.
4. infrared receiving circuit according to claim 1 is characterized in that, also comprises current-limiting resistance, and the power end of described infrared remote receiver connects high level by described current-limiting resistance.
5. infrared receiving circuit according to claim 4 is characterized in that, also comprises isolation capacitance, the earth terminal ground connection of described infrared remote receiver, and described isolation capacitance is connected between the power end and earth terminal of described infrared remote receiver.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101904411A CN102025413A (en) | 2009-09-16 | 2009-09-16 | Infrared receiving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101904411A CN102025413A (en) | 2009-09-16 | 2009-09-16 | Infrared receiving circuit |
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| Publication Number | Publication Date |
|---|---|
| CN102025413A true CN102025413A (en) | 2011-04-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009101904411A Pending CN102025413A (en) | 2009-09-16 | 2009-09-16 | Infrared receiving circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108982137A (en) * | 2018-05-28 | 2018-12-11 | 北京安控科技股份有限公司 | A kind of RTU starting fatigue experimental device and method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2058026U (en) * | 1988-07-20 | 1990-06-06 | 武汉美 | Active infrared alarm for anti-theft |
| CN200976186Y (en) * | 2006-09-15 | 2007-11-14 | 傅耀星 | Infrared data recognition wireless digital transmission alarm |
-
2009
- 2009-09-16 CN CN2009101904411A patent/CN102025413A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2058026U (en) * | 1988-07-20 | 1990-06-06 | 武汉美 | Active infrared alarm for anti-theft |
| CN200976186Y (en) * | 2006-09-15 | 2007-11-14 | 傅耀星 | Infrared data recognition wireless digital transmission alarm |
Non-Patent Citations (2)
| Title |
|---|
| 郑国川: "积分电路与RC滤波电路", 《家庭电子》 * |
| 韩良: "红外遥控接收器中带通滤波器的设计", 《中国集成电路》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108982137A (en) * | 2018-05-28 | 2018-12-11 | 北京安控科技股份有限公司 | A kind of RTU starting fatigue experimental device and method |
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Application publication date: 20110420 |