CN2826836Y

CN2826836Y - Automatic repeating search frequency selection receiving circuit for wireless frequency-modulation signal

Info

Publication number: CN2826836Y
Application number: CN 200520128185
Authority: CN
Inventors: 李正忠
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-01
Filing date: 2005-11-01
Publication date: 2006-10-11
Anticipated expiration: 2015-11-01

Abstract

The utility model discloses a communication signal receiving device, more specifically an automatic repeated search frequency selection receiving circuit for wireless frequency modulation signals. The utility model comprises a frequency modulation carrier signal receiving circuit for receiving signals. The utility model is characterized in that the utility model also comprises a receiving state detecting and controlling circuit for detecting the receiving state of the frequency modulation carrier signal receiving circuit, and a voltage variation reset control circuit for causing the voltage control frequency to be varied from low to high repeatedly according to the signals sent out by the receiving state detecting and controlling circuit; the frequency modulation carrier signal receiving circuit is connected with the voltage variation reset control circuit in series to form a loop through the receiving state detecting and controlling circuit. The utility model has the advantages of simple circuit structure and automatic repeated search function, and a device for transmitting wireless carrier signals and a device for receiving wireless carrier signals are integrated into a head mounted wireless transceiver earphone or an earplug type wireless transceiver earphone by the utility model, so that two-way transmission can be realized, and the effect that the a person who wears the utility model can speak and can listen can be achieved. The utility model is suitable for the fields of wireless earphones for teaching, wireless microphones and wireless earphones for mobile phones, etc.

Description

The automatic repeat search frequency-selecting of a kind of wireless frequency modulation signal receiving circuit

Technical field

The utility model relates to a kind of communication signal receiving system, relates to the automatic repeat search frequency-selecting of a kind of wireless frequency modulation signal receiving circuit specifically.

Background technology

In the radio frequency modulation telecommunication system, receiving system is divided by receive mode, and fixedly frequency and manually frequency-selecting dual mode are arranged.Fixedly in the mode of frequency, emission, receiving circuit are all taked strict frequency stabilization measure, as phase-locked loop circuit etc.Its complex structure, cost height, but good stability.Manual frequency selection method, its receiving circuit does not have special frequency stabilization measure, with manually regulating, compensates, and its emission, receiving circuit are all very simple, and cost is low, but poor stability.In existing disclosed technology, when the wireless frequency modulation signal is launched, receiving circuit is worked at the beginning or just at work, because of its condition of work, operational environment etc. change, the emission of wireless carrier signal, receive frequency will be offset.Receiving circuit just can not receive carrier signal effectively.

The utility model content

The purpose of this utility model provides a kind of wireless frequency modulation signal receiving device of automatic repeat search, can search for automatically, receive frequency and fixing frequency.

For achieving the above object, the utility model adopts following technical scheme: the automatic repeat search frequency-selecting of a kind of wireless frequency modulation signal receiving circuit, it comprises the fm carrier signal receiving circuit that is used for received signal, it is characterized in that: comprise that also the accepting state that the accepting state of a pair of this fm carrier signal receiving circuit detects detects control circuit; With one detect signal that control circuit sends according to accepting state and carry out voltage control and repeat the voltage control circuit that changes from low to high; It is a loop that described fm carrier signal receiving circuit is connected with described voltage control circuit by described accepting state detection control circuit; Described accepting state detects the input of control circuit and obtains the accepting state signal from the fm carrier signal receiving circuit, after its amplification, shaping, filtering, export a state level value by output, send into the input of described voltage control circuit, output output one magnitude of voltage that repeats to change of this voltage control circuit is back to described fm carrier signal receiving circuit and carries out the frequency-selecting processing.

In order to realize technique scheme, the utility model adopts two kinds of designs, one is: the 9th pin of the integrated circuit (IC) 3 in the link of the input that above-mentioned accepting state detects control circuit by resistance R 3 and resistance R 12 and the described fm carrier signal receiving circuit is connected, after capacitor C 8 filtering, be connected with the base stage of triode Q3 by resistance R 12 again, after triode Q3 and triode Q2 amplification shaping, export described voltage control circuit to by resistance R 8; Wherein, integrated circuit (IC) 3 is selected TDA7021 type integrated circuit for use.

Above-mentioned voltage control circuit is made up of a change in voltage reset control circuit and the time main pulse generation circuit that is connected in series with it, this change in voltage reset control circuit receives the status signal of described resistance R 8 outputs by integrated circuit (IC) 2, again through integrated circuit (IC) 2 the 2nd pin, the 1st pin, the 3rd pin, the 7th castor stream is high level and its diode D1 that is connected respectively, diode D2, diode D3, the positive pole output of diode D4, resistance R 6 through different resistance values, R7, R5 and R4 dividing potential drop form a voltage that changes from low to high, through the negative pole of diode D4 and the tie point output of resistance R 4, the positive pole of variable capacitance diode VD in its output point and the fm carrier signal receiving circuit and the tie point of electric capacity V15 join, wherein, integrated circuit (IC) 2 is selected CD4017 type integrated circuit for use.

Main pulse generation circuit is made up of integrated circuit (IC) 1, resistance R 1, R2, capacitor C 16, C17 when above-mentioned, and the 3rd human hair combing waste of integrated circuit (IC) 1 goes out the 14th pin that low frequency pulse signal is connected to integrated circuit (IC) 2 in the described change in voltage reset control circuit; Wherein, to select model for use be NE555 type integrated circuit to integrated circuit (IC) 1.

It two is: the input that above-mentioned accepting state detects control circuit is connected with integrated circuit U4 the 15th pin in the fm carrier signal receiving circuit by a resistance R 11, collect the accepting state signal, this signal flow is crossed the base stage that resistance R 11 and capacitor C 13 and resistance R 10 are connected to triode Q4 jointly, Q4 swings to amplification through triode, signal after paraphase is amplified is by diode D1 rectification, send into the positive input terminal of operational amplifier U3 after resistance R 12 and capacitor C 18 filtering, the negative input end of operational amplifier U3 is communicated with a reference voltage V fr, and its accepting state signal compares by operational amplifier U3 and this reference voltage V fr, export the voltage control circuit input to by resistance R 6 ends after the shaping.

Above-mentioned voltage control circuit by a voltage reset control circuit and a when connected main pulse generation circuit form, this voltage reset control circuit is by resistance R 3, R7, R8, operational amplifier U2, resistance R 4, R5, triode Q2, Q3 form; Main pulse generation circuit is made up of operational amplifier U1, resistance R 1, R2, R13, R14, capacitor C 1, diode D2 when described; The positive input terminal of the operational amplifier U1 of described voltage reset control circuit is connected to reference voltage V fr by resistance R 7, the negative input end of operational amplifier U1 connects the dividing point of resistance R 6, R1 and R13 and R14, the output of operational amplifier U1 is connected with the positive input terminal of operational amplifier U2 by resistance R 2, and the status signal that the output of operational amplifier U1 is sent here according to resistance R 6 presents high resistant or low-resistance; Described status signal is sent into the positive input terminal of operational amplifier U2 through resistance R 2, the negative input end of operational amplifier U2 is connected to reference voltage V fr by resistance R 8, the output of operational amplifier U2 connects the base stage of triode Q2 simultaneously by resistance R 4, with the base stage that is connected triode Q3 by resistance R 5, the collector electrode of triode Q2 connects the 15th pin of the integrated circuit U4 in the described fm carrier signal receiving circuit, and the collector electrode of triode Q4 connects the 16th pin and the positive pole of a variable capacitance diode VD and the link of capacitor C 7 of described integrated circuit U4 simultaneously; Wherein, to select model for use be TDA7088 type integrated circuit to integrated circuit U4.

After the utility model adopts as above technical scheme, its beneficial effect is as follows: 1) since the utility model on the basis of existing fm carrier signal receiving circuit, be connected into the loop with an accepting state detection control circuit and a change in voltage reset control circuit, this fm carrier signal receiving circuit sends to accepting state with FM signal and detects in the control circuit, amplify through the accepting state control circuit, shaping, a state level value is exported in filtering, again through the processing of change in voltage reset control circuit, output one magnitude of voltage that repeats to change, be back in the fm carrier signal receiving circuit, through a variable capacitance diode, its capacitance is changed, cause the resonance frequency of resonant tank to change, realize the purpose of search frequency-selecting.2) circuit structure of this utility model is simple, has automatic function of search repeatedly by low frequency tremendously high frequency signal, when receiving useful signal, by the time main pulse circuit control change in voltage reset control circuit automatically lock, in case the blackout that is received, main pulse circuit control change in voltage reset control circuit automatic unlocking starts the repetitive cycling function of search and searches for, till receiving signal in the time of passing through again; The stability of its circuit control is strong.3) because accepting state is the receiving circuit of repeat search wireless carrier signal automatically, emitter, the receiving system of wireless carrier signal can both be made up of fairly simple circuit, R-T unit can be made of one, be a wear-type or ear type radio receiving/transmitting earphone, realize transmitted in both directions, talkative can listening can be used with fields such as wireless headsets with wireless headset, wireless microphone, mobile phone in teaching.

Description of drawings

Fig. 1 is the utility model receiving system combining structure block diagram

Fig. 2 is embodiment one a combining structure block diagram

Fig. 3 is the circuit connection diagram of Fig. 2

Fig. 4 is embodiment two combining structure block diagrams

Fig. 5 is the circuit connection diagram of Fig. 4

Embodiment

As shown in Figure 1, it is a loop that the utility model detects by fm carrier signal receiving circuit 1, accepting state that control circuit 2 connects with change in voltage control circuit 3, wherein, the output of frequency modulated carrier receiving circuit 1 is connected with earphone and reception antenna, and wherein earphone can be used wireless headset; Frequency modulated carrier receiving circuit 1 adopts conventional wireless frequency modulation to receive element compositions such as application-specific integrated circuit (ASIC), is used for the reception to FM signal; Accepting state detects in the control circuit 2 and comprises basic circuits such as sampling, amplification, shaping, filtering, and the accepting state of the FM reception circuit 1 of wireless headset is checked monitoring in real time.This circuit obtains the two states signal respectively according to the operating state of fm carrier signal receiving circuit, a kind of for not receiving wireless frequency modulation carrier signal state, another kind of for receiving wireless frequency modulation carrier signal state, is different level values with the status signal that is sampled to through amplification, shaping, Filtering Processing, is delivered to the input of change in voltage reset control circuit 3; This change in voltage reset control circuit carries out different processing to the different level value of sending here, when the level value that receives is " not receiving the wireless frequency modulation carrier signal ", this circuit repeats to export from small to large a magnitude of voltage, this voltage is connected to the variable capacitance diode anode in the fm carrier signal receiving circuit, make its capacitance generation variation from big to small, thereby the receive frequency of fm carrier signal receiving circuit is searched for from low to high, automatically reset after searching topmost, from low side, carry out repeatedly again; When the level value that receives transfers " receiving the wireless frequency modulation carrier signal " to, this circuit automatically locks, make the variable capacitance diode both end voltage no longer change, keep the fm carrier signal receiving circuit to be in normal accepting state, in case the level value that receives changes, this fm carrier signal receiving circuit repeats said process.

Below by two embodiment the technical solution of the utility model is done a detailed description.

Embodiment one:

As Fig. 1, Fig. 2, shown in Figure 3, fm carrier signal receiving circuit 1 is by integrated circuit (IC) 3, resistance R 15, R16, R17, capacitor C 1, C2, C3, C4, C6, C7, C9, C10, C11, C12, C13, C14, C15, inductance L 1, L2, variable capacitance diode VD, triode Q1, earphone YD and antenna TX form typical TDA7201 fm carrier signal receiving circuit;

Accepting state detects control circuit 2 by resistance R 3, R9, R11, R12, capacitor C 8, triode Q2, Q3 form, resistance R 3, the sampling of R12 dividing potential drop are joined with integrated circuit TDA7021 the 9th pin, take out the accepting state signal through capacitor C 8 filtering, triode Q2, Q3 amplify shaping, export in the change in voltage control circuit 3 by resistance R 8 again.

Voltage control circuit 3 by the change in voltage reset control circuit and the time main pulse generation circuit tandem compound form, wherein, the change in voltage reset control circuit is by integrated circuit (IC) 2, resistance R 4, R5, R6, R7, diode D1, D2, D3, D4 form; The time main pulse generation circuit by integrated circuit (IC) 1, resistance R 1, R2, capacitor C 16, C17 form; The input of change in voltage reset control circuit is integrated circuit (IC) 2 the 13rd pin, and output is a diode D4 negative terminal, and it is the CD4017 integrated circuit that integrated circuit (IC) 2 is selected model for use; The time integrated circuit (IC) 1 in the main pulse generation circuit to select model for use be the NE555 integrated circuit, integrated circuit NE555 and resistance R 1, R2, capacitor C 16, main pulse was sent into integrated circuit CD4017 the 14th pin input in the change in voltage reset control circuit by integrated circuit NE555 the 3rd pin when C17 constituted low frequency, again through integrated circuit CD4017 the 2nd pin, the 1st pin, the 3rd pin, the 7th castor stream be high level by with its diode D1 that is connected respectively, diode D2, diode D3, the positive pole output of diode D4, resistance R 6 through different resistance values, R7, R5 and R4 dividing potential drop form a voltage that changes from low to high, through the negative pole of diode D4 and the tie point output of resistance R 4, the positive pole of variable capacitance diode VD in its output point and the described fm carrier signal receiving circuit and the tie point of electric capacity V15 join, diode D1, D2, D3, the D4 anode is high level in turn, through resistance R 5, R6, R7 and resistance R 4 dividing potential drops form a level that changes from low to high, link to each other with the variable capacitance diode VD anode in the above-mentioned fm carrier signal receiving circuit, the electric capacity of variable capacitance diode VD is changed from big to small.

Start work or when being in operating state, the 9th pin of integrated circuit TDA7021 fm carrier signal receiving circuit has the signal of an accepting state, do not receive signal and be high level state, through triode Q2, the Q3 amplification is inverted into a low level, forbid holding the 13rd pin to join by resistance R 8 with integrated circuit CD4017, integrated circuit CD4017 is opened like this, one voltage that repeats from low to high to change links to each other with variable capacitance diode VD is anodal from diode D4 negative pole, the capacitance of variable capacitance diode VD is with from low to high the variation of its both end voltage and descending, variable capacitance diode VD, capacitor C 15, the resonance frequency of the resonant tank that inductance L 1 is formed also repeats to change from low to high.Thereby realize search automatically.When TDA7021 fm carrier signal receiving circuit receives carrier signal, the accepting state of the 9th pin is low level, this signal amplifies through triode Q2, Q3 and is inverted into a high level and outputs to integrated circuit CD4017 and forbid end, integrated circuit CD4017 is under an embargo, output state pins constant, the stable output of TDA7021 fm carrier signal receiving circuit, audio signal is amplified driving earphone sounding through triode Q1.

Embodiment two:

As Fig. 1, Fig. 4, shown in Figure 5, fm carrier signal receiving circuit 1 is by integrated circuit U4, resistance R 15, R16, R17, R18, R19, capacitor C 2, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C19, inductance L 1, L2, variable capacitance diode VD, triode Q1, earphone TD, antenna TX forms, and wherein the model of integrated circuit U4 is TDA7088, forms typical TDA7088 fm carrier signal receiving circuit;

Accepting state detects control circuit 2 by operational amplifier U3, diode D1, triode Q4, resistance R 6, R9, R10, R11, R12, and capacitor C 3, C18 form; Resistance R 11 1 ends are the sampling input that accepting state detects control circuit 2, link to each other with integrated circuit TDA7088 the 15th pin in the fm carrier signal receiving circuit, take out the accepting state signal, the other end of resistance R 11 amplifies through paraphase through the base stage that capacitor C 3 is sent into triode Q4, again by diode D1 rectification, after resistance R 12, capacitor C 18 filtering, send into the positive input terminal of operational amplifier U3 and the relatively shaping of normal voltage Vfr of operational amplifier U3 negative terminal input, by resistance R 6 output " accepting state signal " level;

Voltage control circuit 3 by the voltage reset control circuit and the time main pulse generation circuit form, it comprises operational amplifier U1, U2, diode D2, triode Q2, Q3, resistance R 1, R2, R3, R4, R5, R7, R8, R13, R14, capacitor C 1, C12; Wherein, operational amplifier U1, diode D2, resistance R 1, R2, R13, R14, main pulse generation circuit when capacitor C 1 is formed.The input of voltage reset control circuit is the negative input end of operational amplifier U1, and by the resistance R 6 accepting state signals of accepting state detection control circuit output, its output is the output of operational amplifier U2.Output resets, control signal drives triode Q3 by resistance R 4 capacitor C 12 is carried out discharge reduction; Driving triode Q2 by resistance R 5 makes rest-set flip-flop S end in the integrated circuit TDA7088 in the fm carrier signal receiving circuit put high level to open controlled constant-current source and again capacitor C 12 is charged.

When TDA7088 fm carrier signal receiving circuit is not received carrier signal, the sinusoidal wave amplitude of integrated circuit TDA7088 the 15th pin is less, accepting state detects control circuit and detects the corresponding state signal through amplifying the shaping processing, make operational amplifier U3 output be high-impedance state, the voltage reset control circuit and the time main pulse generation circuit output low frequency rectangular pulse that begins to circulate, capacitor C 12 discharge reductions of connecting for integrated circuit TDA7088 the 16th pin through resistance R 5 turn-on transistor Q3 when operational amplifier U2 output is low-voltage; This low-voltage puts high level for integrated circuit TDA7088 the 15th pin rest-set flip-flop S end through resistance R 4 turn-on transistor Q2, makes integrated circuit TDA7088 search for again, so repeatedly.

When TDA7088 fm carrier signal receiving circuit receives carrier signal, the sinusoidal wave amplitude of its 15th pin increases, accepting state detects control circuit and detects the corresponding state signal through amplifying the shaping processing, make operational amplifier U3 output be low resistive state, negative input end by resistance R 6 concatenation operation amplifier U1, pinning operational amplifier U1 makes its output be high-impedance state, the output of operational amplifier U2 also is high resistant, triode Q2, Q3 end, it is locked with triggering to reset, and integrated circuit TDA7088 locks inner accepting state.The audio amplifier circuit that audio signal is formed through triode Q1, resistance R 15, R16, R17, R18, capacitor C 2, C4 amplifies driving earphone YD sounding.

Claims

1, the automatic repeat search frequency-selecting of a kind of wireless frequency modulation signal receiving circuit, it comprises the fm carrier signal receiving circuit that is used for received signal, antenna and earphone with this fm carrier signal receiving circuit is connected is characterized in that: comprise that also the accepting state that the accepting state of a pair of this fm carrier signal receiving circuit detects detects control circuit; With one detect signal that control circuit sends according to accepting state and carry out the voltage control frequency and repeat the voltage control circuit that changes from low to high; It is a loop that described fm carrier signal receiving circuit is connected with described voltage control circuit by described accepting state detection control circuit; Described accepting state detects the input of control circuit and obtains the accepting state signal from the fm carrier signal receiving circuit, after its filtering, amplification shaping, export a state level value by output, send into the input of described voltage control circuit, output output one magnitude of voltage that repeats to change of this voltage control circuit is back to described fm carrier signal receiving circuit and carries out the frequency-selecting processing.

2, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 1 receiving circuit, it is characterized in that: the 9th pin of the integrated circuit (IC) 3 in the link of the input that described accepting state detects control circuit by resistance R 3 and resistance R 12 and the described fm carrier signal receiving circuit is connected, after capacitor C 8 filtering, be connected with the base stage of triode Q3 by resistance R 12 again, after triode Q3 and triode Q2 amplification shaping, export described voltage control circuit to by resistance R 8; The model of described integrated circuit (IC) 3 is TDA7021.

3, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 1 or 2 receiving circuit, it is characterized in that: described voltage control circuit is made up of a change in voltage reset control circuit and the time main pulse generation circuit that is connected in series with it, this change in voltage reset control circuit receives the status signal of described resistance R 8 outputs by integrated circuit (IC) 2, again through integrated circuit (IC) 2 the 2nd pin, the 1st pin, the 3rd pin, the 7th castor stream is high level and its diode D1 that is connected respectively, diode D2, diode D3, the positive pole output of diode D4, resistance R 6 through different resistance values, R7, R5 and R4 dividing potential drop form a voltage that changes from low to high, through the negative pole of diode D4 and the tie point output of resistance R 4, the positive pole of variable capacitance diode VD in its output point and the described fm carrier signal receiving circuit and the tie point of electric capacity V15 join, and the model of described integrated circuit (IC) 2 is the CD4017 type.

4, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 3 receiving circuit, it is characterized in that: main pulse generation circuit is made up of integrated circuit (IC) 1, resistance R 1, R2, capacitor C 16, C17 when described, and the 3rd human hair combing waste of integrated circuit (IC) 1 goes out the 14th pin that low frequency pulse signal is connected to described integrated circuit CD4017.

5, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 4 receiving circuit, it is characterized in that: the model of described integrated circuit (IC) 1 is the NE555 type.

6, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 1 receiving circuit, it is characterized in that: the input that described accepting state detects control circuit is connected with integrated circuit U4 the 15th pin in the described fm carrier signal receiving circuit by a resistance R 11, collect the accepting state signal, this signal flow is crossed the base stage that resistance R 11 and capacitor C 13 and resistance R 10 are connected to triode Q4 jointly, Q4 swings to amplification through triode, signal after paraphase is amplified is by diode D1 rectification, send into the positive input terminal of operational amplifier U3 after resistance R 12 and capacitor C 18 filtering, the negative input end of operational amplifier U3 is communicated with a reference voltage V fr, and described accepting state signal compares by operational amplifier U3 and described reference voltage V fr, export described voltage control circuit input to by resistance R 6 ends after the shaping.

7, the automatic repeat search frequency-selecting of wireless frequency modulation signal as claimed in claim 6 receiving circuit, it is characterized in that: the model of described integrated circuit U4 is the TDA7088 type.

8, as claim 1 or the automatic repeat search frequency-selecting of 6 or 7 described wireless frequency modulation signals receiving circuit, it is characterized in that: described voltage control circuit by a voltage reset control circuit and a when connected main pulse generation circuit form, this voltage reset control circuit is by resistance R 3, R7, R8, operational amplifier U2, resistance R 4, R5, triode Q2, Q3 form; Main pulse generation circuit is made up of operational amplifier U1, resistance R 1, R2, R13, R14, capacitor C 1, diode D2 when described; The positive input terminal of the operational amplifier U1 of described voltage reset control circuit is connected to reference voltage V fr by resistance R 7, the negative input end of operational amplifier U1 connects the dividing point of resistance R 6, R1 and R13 and R14, the output of operational amplifier U1 is connected with the positive input terminal of operational amplifier U2 by resistance R 2, and the status signal that the output of operational amplifier U1 is sent here according to resistance R 6 presents high resistant or low-resistance; Described status signal is sent into the positive input terminal of operational amplifier U2 through resistance R 2, the negative input end of operational amplifier U2 is connected to reference voltage V fr by resistance R 8, the output of operational amplifier U2 connects the base stage of triode Q2 simultaneously by resistance R 4, with the base stage that is connected triode Q3 by resistance R 5, the collector electrode of triode Q2 connects the 15th pin of the integrated circuit U4 in the described fm carrier signal receiving circuit, and the collector electrode of triode Q4 connects the 16th pin and the positive pole of a variable capacitance diode VD and the link of capacitor C 7 of described integrated circuit TDA7088 simultaneously.