CN201839338U - Telephone signal tone detection device for public switched telephone network - Google Patents
Telephone signal tone detection device for public switched telephone network Download PDFInfo
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- CN201839338U CN201839338U CN 201020551640 CN201020551640U CN201839338U CN 201839338 U CN201839338 U CN 201839338U CN 201020551640 CN201020551640 CN 201020551640 CN 201020551640 U CN201020551640 U CN 201020551640U CN 201839338 U CN201839338 U CN 201839338U
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Abstract
A telephone signal tone detection device for a public switched telephone network (PSTN) comprises an amplifying circuit for amplifying an input telephone signal tone, an amplitude envelope detection circuit and an isolating and shaping circuit, wherein the input terminal of the amplitude envelope detection circuit is connected with the output terminal of the amplifying circuit, and the input terminal of the isolating and shaping circuit is connected with the output terminal of the amplitude envelope detection circuit. In the utility model, a high-resistance operation amplifier circuit is adopted to amplify telephone signal tones, and a wave detector composed of a diode, a resistor and a capacitor is used for demodulating amplitude modulation wave envelope of signals; and the amplitude envelope detection circuit is isolated through the high input impedance property of the operation amplifier, and the amplitude modulation wave envelope is shaped and output through the high-gain amplifying property of the operation amplifier. Therefore, the telephone signal tone detection device provided by the utility model has the advantages of simple structure, reliability of working, and the like.
Description
Technical field
The utility model belongs to the public switched telephone network (PSTN) communication technical field, is specifically related to public switched telephone network (PSTN) subscriber terminal equipment signal tone checkout gear.
Background technology
Public switched telephone network (PSTN) (PSTN:Public Switched Telephone Network) telephone signal tone is the audio prompt signal that is sent to user terminal by stored-program control exchange, comprises dialing tone, busy tone and ring-back tone.GB GB3380-82 " automatic telephone switching network ringing-current and signal tone " regulation program controlled telephone signal tone frequency is 450 ± 25Hz.Wherein: dialing tone is a continuous signal; Busy tone is 0.35s ± 0.05s, uniformly-spaced disconnected, continuous signal; Ring-back tone is that 1s is continuous, disconnected disconnected, the continuous signal that does not wait at interval of 4s.The automation electronic system equipment of various access public switched telephone network (PSTN), all need detect, differentiate the stored-program control exchange present located operating state that telephone signal tone is pointed out as tele-control system, automatic alarm system, automatic response data transmission system etc., just can carry out corresponding operational processes.
Existing telephone signal tone testing circuit uses LM567 ATD/phase-locked loop (Tone decoder/phase-locked loop) integrated circuit, to frequency is that 450 ± 25Hz signal amplitude modulating wave locks detection, and the centre frequency that detection is obtained is that the interrupted envelope of 450Hz signal is sent to monolithic computer and discerns.This circuit has 3 deficiencies: the one, and locking frequency and locking bandwidth debug difficulties; The 2nd, locking frequency is subject to ambient temperature effect with the locking bandwidth and produces drift, causes job insecurity; The 3rd, the locking bandwidth is narrower, when program controlled telephone signal tone 450Hz signal frequency have ± be difficult for tracking lock during the 25Hz deviation, often make to detect and lost efficacy.
Summary of the invention
Technical problem to be solved in the utility model is to overcome existing public switched telephone network (PSTN) telephone signal tone detection circuit debug difficulties, job insecurity and shortcoming that can not the tracking signal frequency departure, provide a kind of simple in structure, production cost is low, reliable operation, the public switched telephone network (PSTN) telephone signal sound detection device that need not to debug.
Solving the problems of the technologies described above the technical scheme that is adopted comprises: to the amplifying circuit that amplifies of telephone signal tone of input; The amplitude envelope detecting circuit, the output of the input termination amplifying circuit of this circuit; It also comprises the isolation shaping circuit, and the input termination of this circuit is isolated the output of shaping circuit.
Amplifying circuit of the present utility model is: telephone signal tone Vin is by the end input of capacitor C 1, the in-phase input end of another termination operational amplifier U1A of capacitor C 1 also passes through resistance R 1 ground connection, the inverting input of operational amplifier U1A connects an end of capacitor C 2 and connects the positive pole of the diode D1 of output, output termination amplitude envelope detecting circuit, the other end ground connection of capacitor C 2 by resistance R 3 by resistance R 2.
The utility model adopts the high resistance operating amplifier circuit that telephone signal tone is amplified, wave detector with diode, resistance, electric capacity composition demodulates the Modulation and Amplitude Modulation wave envelope of signal, the operational amplifier high input impedance charcteristic is isolated the amplitude envelope detecting circuit, operational amplifier high-gain amplification characteristic has characteristics simple in structure, reliable operation with the output of AM wave envelope shaping.
Description of drawings
Fig. 1 is an electrical principle block diagram of the present utility model.
Fig. 2 is an electronic circuit schematic diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing and each embodiment the utility model is further described, but the utility model is not limited to these embodiment.
Embodiment 1
Fig. 1 is an electrical principle block diagram of the present utility model.In Fig. 1, the public switched telephone network (PSTN) telephone signal sound detection device of present embodiment comprises that amplifying circuit, amplitude envelope detecting circuit and isolation shaping circuit connect and compose.The output termination amplitude envelope detecting circuit of amplifying circuit, the output termination of amplitude envelope detecting circuit is isolated shaping circuit.
Fig. 2 is an electronic circuit schematic diagram of the present utility model.As shown in Figure 2, the amplifying circuit of present embodiment is connected and composed by operational amplifier U1A, resistance R 1, resistance R 2, resistance R 3, capacitor C 1, capacitor C 2, can adopt model in the present embodiment is the operational amplifier of TL062, and also can adopt model is the operational amplifier of LM358.Telephone signal tone Vin is by the end input of capacitor C 1, the in-phase input end of another termination operational amplifier U1A of capacitor C 1 also passes through resistance R 1 ground connection, the inverting input of operational amplifier U1A was connected resistance R 2 and is connect an end of capacitor C 2 and connect output, output termination amplitude envelope detecting circuit, the other end ground connection of capacitor C 2 by resistance R 3.
The amplitude envelope detecting circuit of present embodiment is connected and composed by diode D1, capacitor C 3 and resistance R 4.Output, multipole that the positive pole of diode D1 meets operational amplifier U1A connect an end of capacitor C 3 and isolate shaping circuit also by resistance R 4 ground connection, the other end ground connection of capacitor C 3.
The isolation shaping circuit of present embodiment is made of operational amplifier U1B, and can adopt model in the present embodiment is the operational amplifier of TL062, and also can adopt model is the operational amplifier of LM358.Negative pole, reverse input end that the in-phase input end of operational amplifier U1B meets diode D1 meet reference level Vref, output output telephone signal tone Vout.
Operation principle of the present utility model is as follows:
Telephone signal tone is input to in-phase input end into operational amplifier U1A by an end of capacitor C 1, operational amplifier U1A amplifies the telephone signal tone amplitude of carrying out, telephone signal tone after amplitude is amplified outputs to the diode D1 in the amplitude envelope detecting circuit, diode D1 carries out halfwave rectifier to the phone 450Hz signal after amplifying, the signal that promptly has only positive half cycle is by diode D1, and negative half-cycle signal can not pass through diode D1.Positive half cycle signal by diode D1 charges to capacitor C 3, sets up positive half cycle crest voltage.Between the signal negative half-cycle, the voltage of setting up on the capacitor C 3 is by resistance R 4 discharges, because capacitor C 3, resistance R 4 numerical value are enough big, make discharge time constant (R4, the product of C3) much larger than cycle of telephone signal voice frequency 450Hz, and therefore discharge time constant sets up the voltage waveform of telephone signal tone amplitude envelope much smaller than the time of telephone signal tone amplitude envelope on capacitor C 3.Isolating shaping circuit has two effects, and one is to utilize the high resistant characteristic of operational amplifier U1B that the amplitude envelope detecting circuit is isolated with the circuit that is connected later; Another effect is to the shaping of telephone signal tone amplitude envelope voltage, as long as the telephone signal tone amplitude envelope voltage on the capacitor C 3 is greater than reference voltage Vref, its output is high level, otherwise output then is low level, what therefore finally obtain after isolating shaping circuit output is the neat rectangular voltage square wave in edge, send into single-chip microcomputer after this square wave handled and discern, thereby finish the detection of telephone signal tone.
Claims (2)
1. public switched telephone network (PSTN) telephone signal sound detection device is characterized in that comprising:
The amplifying circuit that amplifies of telephone signal tone to input;
The amplitude envelope detecting circuit, the output of the input termination amplifying circuit of this circuit;
It also comprises the isolation shaping circuit, and the input termination of this circuit is isolated the output of shaping circuit.
2. according to the described public switched telephone network (PSTN) telephone signal of claim 1 sound detection device, it is characterized in that said amplifying circuit is: telephone signal tone Vin is by the end input of capacitor C 1, the in-phase input end of another termination operational amplifier U1A of capacitor C 1 also passes through resistance R 1 ground connection, the inverting input of operational amplifier U1A connects an end of capacitor C 2 and connects the positive pole of the diode D1 of output, output termination amplitude envelope detecting circuit, the other end ground connection of capacitor C 2 by resistance R 3 by resistance R 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201020551640 CN201839338U (en) | 2010-09-29 | 2010-09-29 | Telephone signal tone detection device for public switched telephone network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201020551640 CN201839338U (en) | 2010-09-29 | 2010-09-29 | Telephone signal tone detection device for public switched telephone network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201839338U true CN201839338U (en) | 2011-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201020551640 Expired - Fee Related CN201839338U (en) | 2010-09-29 | 2010-09-29 | Telephone signal tone detection device for public switched telephone network |
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| Country | Link |
|---|---|
| CN (1) | CN201839338U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108418590A (en) * | 2018-02-08 | 2018-08-17 | 北京瑞芯谷科技有限公司 | radio frequency transmission chip |
-
2010
- 2010-09-29 CN CN 201020551640 patent/CN201839338U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108418590A (en) * | 2018-02-08 | 2018-08-17 | 北京瑞芯谷科技有限公司 | radio frequency transmission chip |
| CN108418590B (en) * | 2018-02-08 | 2022-07-19 | 北京瑞芯谷科技有限公司 | Radio frequency transmission chip |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110518 Termination date: 20110929 |