CN2543284Y

CN2543284Y - Radio-frequency two-way speech teaching device

Info

Publication number: CN2543284Y
Application number: CN 02237114
Authority: CN
Inventors: 王诚
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-06
Filing date: 2002-06-06
Publication date: 2003-04-02
Anticipated expiration: 2012-06-06

Abstract

The utility model discloses a radio-frequency wireless two-way speech teaching device comprising a host computer for teacher use and a sub-computer for student use, which is characterized in that capacitors with conversed frequency points are connected in series in an oscillator circuit of a transmitting circuit of the host computer for teacher use and the sub-computer for student use respectively. A two-way analog switch with a short circuit to ground which is controlled by a single chip microcomputer is connected in parallel with the capacitor. A two-way analog switch which is controlled by the single chip microcomputer is connected in series with an output terminal for a radio-frequency signal of the transmitting circuit. A receiving circuit of the host computer for teacher use is provided with two unit circuits with different receiving frequency points. A voltage control terminal of a receiving circuit of the sub-computer for student use is provided with three-group tuned circuits with different frequency points.

Description

Radio frequency wireless bidirectional phonetic teaching device

Technical field:

The utility model audiovisual teaching equipment is applicable to indoor electrochemical phonetic teaching.

Background technology:

Existing electrochemical phonetic teaching equipment is with the transmission means branch, and mainly contain two big classes: a class is wired, and another kind of is wireless.The former house wiring is installed complicated, the expense height; The latter divides by transmission means also two big classes, and a kind of is radio frequency transmission, and another kind is an infrared transmission.Patent Office of the People's Republic of China's Granted publication in 25 days October nineteen ninety-five a kind of " mobile wireless phonetic teaching device " utility model patent, it on this utility model patent technical spirit a cover transmitter and receiver, can only realize that the teacher says that the student listens, and is impractical in modernizing teaching.Patent Office of the People's Republic of China's Granted publication in 18 days April calendar year 2001 a kind of " infrared radio bi-directional language instructional device " utility model patent, this utility model deposits that following some is obviously not enough: 1, because infrared interconnection technique has directive property and can not covering property, therefore moving of people or object all disturbs, and the student's of different seat numbers audibility is different; 2, have only single emission frequency, can't realize the multimachine intercommunication, lost the characteristics and the meaning of modern electronic teaching; 3, the record function that does not have modern phonetic study.

Summary of the invention:

Technical problem to be solved in the utility model is to solve the technical barrier of radio frequency wireless bidirectional phonetic teaching device multimachine intercommunication.

The technical scheme of technical problem to be solved in the utility model is:

A kind of radio frequency wireless bidirectional phonetic teaching device, comprise that the teacher uses extension set with main frame and student, described teacher is made up of radiating circuit, receiving circuit, coding circuit, function commutation circuit and power amplifier with main frame, described student is made up of radiating circuit, receiving circuit, control circuit and the big circuit of audio interface folding and unfolding with extension set, it is characterized in that:

Be serially connected with the electric capacity that changes frequency in a, the crystal oscillator loop of teacher with the radiating circuit of main frame, be parallel with the shorted to earth bidirectional analog switch S B2 that is controlled by single-chip microcomputer on this electric capacity, the radiofrequency signal output serial connection one of radiating circuit is controlled by the bidirectional analog switch S B1 of single-chip microcomputer; Being provided with two different element circuits that receive frequency in the receiving circuit of teacher with main frame forms;

Be serially connected with the electric capacity that changes frequency in b, the crystal oscillator loop of student with the radiating circuit of extension set, be parallel with the shorted to earth bidirectional analog switch S B4 that is controlled by single-chip microcomputer on this electric capacity, the radiofrequency signal output serial connection one of radiating circuit is controlled by the bidirectional analog switch S B2 of single-chip microcomputer; The student is provided with the tuning circuit of three group of received different frequent points with the voltage controling end (VCO) of the receiving circuit of extension set.

The utility model has following advantage than prior art:

1, in the classroom, can realize between the arbitrarily individual student or teacher and the intercommunication between the student arbitrarily;

2, the student can send out request command to teacher when the teacher gives lessons to the full student of class;

3, use single chip machine controlling circuit simple but powerful.

Description of drawings:

Fig. 1 is teacher described in the utility model uses extension set with main frame and student a composition frame chart;

Fig. 2 is the circuit structure block diagram of teacher with main frame;

Fig. 3 is the circuit structure block diagram of student with extension set;

Fig. 4 is the electrical schematic diagram of teacher with a specific embodiment of main frame;

Fig. 5 is the electrical schematic diagram of student with a specific embodiment of extension set;

Embodiment:

Referring to Fig. 1, Fig. 2 and Fig. 3, radio frequency wireless bidirectional phonetic teaching device described in the utility model, comprise that the teacher uses extension set with main frame and student, described teacher is made up of radiating circuit, receiving circuit, coding circuit, function commutation circuit and power amplifier with main frame, and described student is made up of radiating circuit, receiving circuit, control circuit and the big circuit of audio interface folding and unfolding with machine.

Referring to being serially connected with the capacitor C 15 that changes frequency in the crystal oscillator loop of the described teacher of Fig. 4 with the radiating circuit of main frame, be parallel with the shorted to earth bidirectional analog switch S B2 that is controlled by single-chip microcomputer IC8 (AT89C51) on this capacitor C 15, the radiofrequency signal output of radiating circuit (9 pin) serial connection one is controlled by the bidirectional analog switch S B1 of single-chip microcomputer IC8 (AT89C51); Being provided with two different element circuits that receive frequency in the receiving circuit of teacher with main frame forms.This element circuit is made up of special-purpose FM reception integrated circuit (IC) 2 (TDA7021) and IC3 (TDA7021) and peripheral circuit respectively, wherein links to each other with the input (2,3 pin) of power amplifier sound intermediate frequency amplifier IC5 (TDA7050) behind the output of IC2 (14 pin) series capacitance C25, resistance R 9, the bidirectional analog switch S B9; Wherein be connected to the communication port (10 pin) of single-chip microcomputer IC8 after the output of IC3 (14 pin) series capacitance C37, the resistance R 11.

Referring to being serially connected with the capacitor C 31 that changes frequency in the crystal oscillator loop of Fig. 5 student with the radiating circuit of extension set, be parallel with the shorted to earth bidirectional analog switch S B4 that is controlled by single-chip microcomputer IC4 (AT89C2051) on this capacitor C 31, the radiofrequency signal output of radiating circuit (9 pin) serial connection one is controlled by the bidirectional analog switch S B2 of single-chip microcomputer IC4; Referring to Fig. 5, the student is made of special-purpose FM reception integrated circuit (IC) 1 (TDA7021) and peripheral circuit with the receiving circuit of extension set, the voltage controling end of FM reception integrated circuit TDA7021 (5 pin) is provided with the tuning circuit of three groups of different frequent points, this tuning circuit is composed in parallel by inductance L 4 and capacitor C 14, inductance L 3 and capacitor C 13, inductance L 2 and capacitor C 12 respectively, is serially connected with the O/I mouth of single-chip microcomputer IC4.

Referring to Fig. 4, because the teacher is for the orthoepy of syllable of training of students, a word, a sentence, a paragraph in phonetic teaching, read aloud repeatedly, be the hardship of avoiding the teacher to read aloud repeatedly, first important additional technical feature of the present utility model is the teacher with being provided with the playback circuitry that is controlled by single-chip microcomputer IC8 in the main frame, and this playback circuitry is connected and composed successively by microphone MIC, amplifying circuit and recording playback special chip IC 7 (ISD4000).The address wire ISS of described recording playback special chip IC 7, input end of clock SCLK, serial output terminal MOSI, middle fracture INT, address clock end RAC are connected with the O/I of single-chip microcomputer IC8 respectively, are connected with the input of power amplifier behind audio signal output end AUOUT series coupled capacitor C 45 and the bidirectional analog switch S B10.Described power amplifier is served as by known special chip TDA7050 (IC5).

Referring to Fig. 4, in order to show that clearly the student uses the extension set current working state, promptly be in intercommunication or at a request command, second additional technical feature of the present utility model is the teacher with the address display circuit that is provided with a controlled single-chip microcomputer IC8 (AT89C51) in the main frame, this display circuit by the serial decoding circuit and with coding circuit in key letter K1---the corresponding LED 1 of K64---LED64 forms.Described serial decoding circuit seals in by 8 and goes out that 8 bit shift register IC10---IC17 (74LS164) forms.Being a teacher and pressing key letter K1---during arbitrary key, pairing light-emitting diode is promptly lighted among the K64; When a certain student sent request, pairing just the beginning glimmered.

Below in conjunction with accompanying drawing the course of work of the present utility model is described in detail so that the public fully understands the technical solution of the utility model.

Referring to Fig. 4, S5 is " all-pass ", " intercommunication " function key." all-pass " LED 67 is bright during start, expression is operated in " all-pass " state, when pressing the S5 key, the 3 pin output high level of single-chip microcomputer IC9, " intercommunication " LED 68 is bright, bidirectional analog switch S B2 closure, the frequency of switching radiating circuit IC1 (MC2833) is operated in " intercommunication " state.

When pressing the S5 key again, LED 67 and LED68 are simultaneously bright, IC9 control bidirectional analog switch S B2 closure, disconnection, and closed, disconnection circulation is switched, and IC1 is operated in " all-pass ", " intercommunication " two kinds of circulation switching states.That is to say that teacher described in the utility model has three kinds of operating states with radiating circuit in the main frame, i.e. " all-pass ", " intercommunication " and " all-pass ", " intercommunication " circulation switch operating state.Below " all-pass ", " intercommunication " circulation switch operating state are defined as " two saying " operating state.

The detailed operation process of above-mentioned three kinds of states is:

Referring to Fig. 4, during start, be " all-pass " operating state, 1 pin preset of single-chip microcomputer IC9 (AT89C2051), 6 pin output high level, LED 67 is bright, 3 pin output low levels, the SB2 open circuit of analog switch IC18, make C13, after the C15 series connection, be connected across on 15 pin of modulating emission circuit IC1, establish a frequency modulation emission frequency, this frequency is that the teacher launches FM signal employed frequency to whole students with extension set with main frame.

When pressing S5, the 6 pin output low levels of single-chip microcomputer IC9, " all-pass " LED 67 goes out, 3 pin of IC9 are exported high level (" intercommunication " LED 68 is bright), are added to the SB2 control end of analog switch IC18, the SB2 conducting, the C15 short circuit, have only C14 to be connected across on 15 pin of modulating emission circuit IC1 this moment, thereby produce another emission frequency, and this frequency is a frequency used when using extension set " intercommunication " with the student.

Referring to Fig. 4, when pressing S5 again, " all-pass " " intercommunication " LED 67, LED68 are bright, are operated in " two saying " state.During work, the impulse level of 3 pin of single-chip microcomputer IC9 output certain frequency is added to the SB2 control end, and the break-make of control analog switch SB2 makes modulating emission circuit IC1 time-sharing work on " all-pass " " intercommunication " two states.Because of SB2 switching frequency height, so LED 67, it is bright entirely that LED68 thinks, the student is used extension set FM reception circuit, and under the state of two reception frequencies coexistence, (a kind of is " teaching " state, a kind of is " intercommunication " state), the student of different frequent points uses extension set, can both receive two frequency FM signal being sent by a modulating emission circuit timesharing, so that the teacher can also talk with in the student when giving lessons.

Because the signal of two transmitter emission same frequencys can not be arranged in a work group simultaneously, otherwise can produce interference, therefore teacher described in the utility model is provided with the bidirectional analog switch with main frame and student with the signal output part of the radiating circuit of extension set, as long as two ones or multi-section machine are arranged when the intercommunication by the teacher with single-chip microcomputer IC8 control in the main frame, arbitrary in whole work group instantaneously have only a machine to be in emission state.Be serially connected with bidirectional analog switch S B1 referring to Fig. 4 teacher with radiofrequency signal output 9 pin of radiating circuit IC1 (MC2833) in the main frame, control its break-make by single-chip microcomputer IC8.Referring to Fig. 5, the student is serially connected with bidirectional analog switch S B2 with radiofrequency signal output 9 pin of radiating circuit IC3 (MC2833) in the extension set, and IC4 controls its break-make by single-chip microcomputer (AT89C2051).

Referring to Fig. 4, under this bright state of " intercommunication " LED 72, single-chip microcomputer IC9 (AT89C2051) 16 pin output high level, be added to bidirectional analog switch I C21 (CD4066) SB9 control end, the SB9 closure, the frequency modulation IC2 that meets sb. at the airport receives the FM signal with extension set emission from the student, delivers to audio frequency power amplifier IC5 (TDA7050) by the output of IC2 (TDA7021) 14 pin by SB9, promotes the loudspeaker Y sounding.

When pressing the S6 key, " recording " LED 73 is bright, and under this state, 17 pin of IC9 are exported high level, are added to the SB10 control end of IC21, the SB10 closure.As IC7 (ISD4000) during in tone playing state, audio signal is by the 13 pin output of IC7, delivers to audio frequency power amplifier by SB10 and amplifies and promote the loudspeaker Y sounding.

When pressing the S6 key again, " program " LED 74 is bright, under this state, the 18 pin output high level of IC9, be added to the SB11 control end of bidirectional analog switch I C21, the SB11 closure, at this moment, after delivering to audio frequency power amplifier IC5 (TDA7050) and amplify by SB11 by the peripheral hardware audio signal of CK3 interface input, promote the loudspeaker Y sounding.

" intercommunication ", " recording ", " program " three kinds of operating states are switched by the circulation of S6 key control.

When starting shooting referring to Fig. 4, " recording ", " program " LED 69 and LED75 go out, 2 pin, the 19 pin output low levels of IC9 this moment (AT89C2051), and the SB8 of analog switch IC20, SB7 open circuit is for waiting for broadcast state.

When pressing the S7 key, " recording " LED 69 is bright, the 2 pin output high level of IC9 is added to the SB8 control end of analog switch IC20 (CD4066), the SB8 closure, export by 13 pin at this state I C7 (ISD4000) playback signal, deliver to the input (5 pin) of IC1 (MC2833) by SB8, TX1 launches by the sky.

When pressing the S7 key again, " program " LED 75 is bright, the 19 pin output high level of IC9, be added to the SB7 control end of bidirectional analog switch I C20, the SB7 closure is under this state, the audio signal of interface CK3 input by 6 pin that SB7 sends into IC1, is outwards launched from sky TX1 after the output of 9 pin.

" wait ", " recording ", " program " three kinds of operating states are switched by the circulation of S7 key control.

Referring to Fig. 4, during start, " teaching " LED 70 is bright, 14 pin of single-chip microcomputer IC9 are exported high level, are added in the SB5 control end of analog switch IC20, the SB5 closure, under this state, FM reception IC circuit 2 is received the FM signal of student with the extension set emission, through the 14 pin output audio signals of IC2, sends into the 16 pin recorded audio signals inputs of playback circuitry IC7 by SB5.

Referring to Fig. 4, when pressing the S1 key, " program " refers to that lamp LED71 is not bright, and 15 pin of IC9 are exported high level, is added to the SB6 control end of IC20, and the SB6 closure under this state, is delivered to " program " audio signal of CK3 input 16 pin signal input parts of IC circuit 7.

Referring to Fig. 4, in " teaching ", under " program " two states, the voice audio signals that the MIC microphone is sent into, can be simultaneously from the 16 pin typing together of IC7.

" teaching ", " program " two kinds of operating states are switched by the control of S1 operating key.

Referring to Fig. 4, during start, " recording " LED 66 is bright, the 8 pin output high level of single-chip microcomputer IC9 (AT89C2051), and driving LED 66 is bright, 9 pin output low levels, control single chip computer IC8 (AT89C51) 5 pin are low level, LED 65 goes out.When 5 pin of single-chip microcomputer IC8 are low level, be " recording " operating state.

Referring to Fig. 4, when pressing the S2 key, " playback " LED 65 is bright, the 8 pin output low levels of IC9, and LED 66 goes out; 9 pin output high level, 5 pin of control single chip computer IC8 are high level.When 5 pin of IC8 are high level, be " playback " operating state.

" recording ", " playback " two kinds of operating states are switched by S2 control.

Referring to Fig. 4, when the S2 key is chosen in " recording " state, single-chip microcomputer IC9 (AT89C2051) 7 pin output high level, LED 77 goes out.

Referring to Fig. 4, when pressing the S3 key, the 7 pin output low levels of IC9, LED 77 is bright.7 pin of control single chip computer IC8 (AT89C51) become low level, and playback circuitry IC7 this moment (ISD4000) records, and when pressing the S3 key again, is returned to initial state, and recording stops and forming one section.Continuation is then recorded next section by S3.

Referring to Fig. 4, when the S2 key is selected " playback ", single-chip microcomputer IC9 (AT89C2051) 7 pin output high level, LED 77 goes out.

Referring to Fig. 4, when pressing the S3 key, low level pulse of 7 pin output of IC9, LED 77 is once glittering, makes IC8 (AT89C51) 7 pin obtain a low level pulse and triggers, and this moment, playback circuitry IC7 was just in playback, promptly play one section, after one section end, stop playback automatically, then play next section by the S3 key again.

Referring to Fig. 4, when S3 key during at " recording " state, for resetting, LED 76 is once glittering by the S4 key, again when " recording ", again since first section.

Referring to Fig. 4, when S3 key during at " playback " state, for resetting, LED 76 is once glittering by the S4 key, again during playback, again since first section.

Referring to Fig. 4, the teacher has 64 coding key (K1-K64) with main frame.Every student of each coding representative uses the extension set code clerk.When start, single-chip microcomputer IC8 (AT89C51) 9 pin presets, 64 LED 1-LED64 of K1-K64 keyboard go out.When by arbitrary K key, respective leds is bright, and 8 pin of single-chip microcomputer IC8 become low level by high level, are added to the SB3 control end of bidirectional analog switch I C18, the SB3 open circuit.The 11 pin TXD communication ports output serial code signal of single-chip microcomputer IC8 sends to modulating emission circuit IC1 (MC2833) by SB4 and is launched by antenna TX1.After the serial code signal sent, 8 pin of IC8 became high level by low level, control SB3 closure, and this signal is delivered to modulating emission circuit IC1 (MC2833) by R3C3, is launched by antenna TX1.During again by corresponding K key, respective leds is gone out, and with extension set for, during by teacher's usefulness main frame K key, respective leds is bright for controlled student.The student is automatically switched to " intercommunication " operating state with extension set, the teacher uses the extension set direct dialogue with main frame and student, and when pressing the K key again, light-emitting diode goes out, close student's " intercommunication " function with extension set, the student is automatically switched to " voice " initial condition with extension set.When by the above coding key K of any two or two, 11 pin of single-chip microcomputer IC8, what export is the circulation serial code signal of two or more compositions, between each code signal, isolate by synchronization pulse, two identical code signals are formed a signal element, each signal element, control the on off state of corresponding student with extension set " intercommunication " function, the selected student of circulation serial code signal controlling uses the extension set periodic duty at the timesharing state, make have only a pair of receive-transmit system work with the scene, avoid the phase mutual interference.Circulation serial code signal by the student with the extension set code signal with isolate that the synchronizing signal of coding forms, in serial code, all code signal width be identical be that the synchronizing signal width also is identical.With the code signal is low level, and synchronizing signal is that high level is formed new serial synchronizing signal, with 8 pin of single-chip microcomputer IC8 and the circulation serial code signal of 11 pin, and output synchronously, audio signal and code signal are sent by timesharing.

Referring to Fig. 4, when synchronizing signal is exported by 8 pin of single-chip microcomputer IC8, the SB3 closure of bidirectional analog switch I C18, audio signal is delivered to modulating emission circuit IC1 to aerial emission by SB3 and coupling resistance R3, capacitor C 3; When pressing K1---during any key letter, the SB3 of bidirectional analog switch I C18 then disconnects among the K64, cuts off audio signal, and the code signal of the 11 pin output of single-chip microcomputer IC8 is directly delivered to modulating emission circuit IC1 by coupling resistance R3, capacitor C 3 and launched.

Referring to Fig. 4, the teacher uses extension set launching code control signal with the main frame timesharing to the student, each student of loop control makes each student be in time-sharing work state (referring to Fig. 5) with extension set speech modulation radiating circuit IC3 (MC2833) with the break-make of extension set " intercommunication " function.

Referring to Fig. 4, the teacher receives the speech modulation signal of a plurality of students with the extension set emission with main frame FM reception IC circuit 2 (TDA7021) timesharing, under certain timesharing frequency, guarantee that each student can be received reduction with main frame by the teacher preferably with the voice signal that extension set sends, and guarantees tonequality.

Referring to Fig. 5, the student is the same with main frame FM reception circuit with the teacher with extension set FM reception IC circuit 1 (TDA7021), and timesharing receives each student and comprises the speech modulation signal with main frame from the teacher with extension set.

Realized that in said process the teacher uses extension set with main frame and student, the student uses extension set and student with " intercommunication " function between extension set, forms interregional wireless duplex signaling net, realizes that this function is by the user control of teacher with main frame.

Referring to Fig. 4 and Fig. 5 in radio frequency wireless bidirectional phonetic teaching device described in the utility model, " voice " state duplex signaling, have two frequencies, and two frequencies are realized with host computer control automatically by the teacher: 1. when the teacher starts shooting with main frame, when being the initial condition of teacher's usefulness main frame and student's usefulness extension set, the teacher is received as a frequency with main frame and student with the extension set emission.The teacher when " intercommunication " state, the teacher is received as another frequency with main frame and student with the emission of extension set with S5 (teaching) key in the main frame.

Referring to Fig. 5, during start, the student is operated in " frequency modulation " with extension set and receives operating state, 1 pin preset of single-chip microcomputer IC4 (AT89C2051), and 11,14,15,16,17,18 pin are low level, 13 pin are high level.At this moment, the 2 pin output low levels of single-chip microcomputer IC4 are added in analog switch IC5 (CD4066) SB1 control end, and the SB1 open circuit cuts off L5 frequency induction signal; 14,15 pin output low levels are cut off FM reception IC circuit 1 (L4, C14 and L3, C13) two external tuning circuit power supplies.The 16 pin output low levels of IC4 are added in the SB4 control end, and the SB4 open circuit after making C31 and C30 connecting, is connected across on modulating emission circuit IC3 (MC2833) strength circuit 15 pin, set up an emission frequency.The 17 pin output low levels of IC4 are added in the SB3 control end, and the SB3 open circuit cuts off modulating emission circuit IC3 power supply.The 18 pin output low levels of IC4, control SB2 open circuit cuts off the radiofrequency signal that modulating emission circuit IC3 the 9th pin is exported.The 13 pin output high level of IC4 is as the power supply of the tuning circuit that is made of L2, C12.Regulate variable capacitance C12, can select to listen to the checking station arbitrarily.Referring to Fig. 5, the FM radio station signal that antenna TX1 receives after FM reception IC circuit 1 (TDA7021) demodulation, by the 3 pin input of 14 pin output audio signals from audio frequency power amplifier IC2 (TDA7050), after IC2 amplifies, by the output of 6,7 pin, promotes the loudspeaker Y sounding.

Referring to Fig. 5, when pressing the S1 key, loudspeaker Y " toot " one, the student is switched to " audio frequency " operating state with extension set, single-chip microcomputer IC4 (AT89C2051) (13,14,15,16,17,18 pin output low levels, 11 pin output high level) 13,14,15 pin output low levels, the power supply of cut-out IC1 tuning circuit, IC1 does not work.17 pin output low levels are added to the control end of SB3, SB3 open circuit, the power supply that cuts off modulating emission circuit IC3.The 11 pin output high level of IC4 is added to the control end of the SB1 of bidirectional analog switch I C5, SB1 closure.Send into audio frequency power amplifier IC2 (TDA7050) by SB1 from 2,3 pin by the coil-induced audio signal of L5 bar magnet and amplify,, promote the loudspeaker Y sounding by the output of 6,7 pin.

Referring to Fig. 5, when pressing the S1 key again, loudspeaker " are pouted, are pouted " two, and the student is switched to " voice " operating state with extension set.11,13,15,16,17, the 18 pin output low levels of single-chip microcomputer IC4,14 pin output high level.The 11 pin output low levels of IC4, control bidirectional analog switch S B1 open circuit, the frequency induction signal that cuts off L5.13,15 pin output low levels, the power supply of cut-out FM reception IC circuit 1 external two tuning circuits (L2, C12 and L4, C14).The 17 pin output low levels of IC4, control bidirectional analog switch S B2 open circuit cuts off the radiofrequency signal that modulating emission circuit IC3 (MC2833) is sent, and its effect is identical with main frame in the teacher with principle.The 16 pin output low levels of IC4, control SB4 opens a way, and makes the external capacitor C31 of IC3 strength circuit, is attempted by 15 pin after the C32 series connection, sets up another emission frequency.14 pin of IC4 output high level is for the external tuning circuit L3 of the 5 pin C13 of FM reception IC circuit 1 provides power supply.Under " voice " state, sending and receiving frequency unanimity.The teacher is received by TX1 with the FM signal that main frame sends, and after the IC1 demodulation, by 14 pin output audio signals, directly sends into 2 and 3 pin of IC2, amplifies the back and promotes the loudspeaker Y sounding by the output of 6 and 7 pin.

Referring to Fig. 5, if again when press the S1 key, loudspeaker " pout, pout, toot " three, the student is switched to " frequency modulation " operating state (initial condition) with extension set.Press the S1 key, the student is with " frequency modulation (FM) " with extension set, " audio frequency (AM) ", " voice (YY) " operating state switching circulation.

Referring to Fig. 5, S2 is that the student uses the call extension key.When the student uses the main frame intercommunication with the extension set requirement with the teacher, by this key.The S2 function key only works when the S1 function key is switched at " voice " state, and the S1 key is under other state, and the S2 function key is inoperative.The student when " voice " state, press the S2 key with extension set, and loudspeaker send " too, too " sound, 11,13, the 15 pin output low levels of single-chip microcomputer IC4, and 16,17,18 pin of IC4 are exported high level.The 11 foot control system SB1 open circuit of IC4 disconnects L5 frequency induction signal; 13, the 15 pin output low levels of IC4, make tuning circuit L3, C13 and L2, C12 outage, the 16 pin output high level of IC4 is added to the SB4 control end of bidirectional analog switch I C5 (CD4066), the SB4 closure, the C31 short circuit, make modulating emission circuit IC3 make external capacitor C31 shorted to earth, determine new emission frequency.14 pin of IC4 are exported high level, offer the external tuning circuit L4 of 5 pin of FM reception IC circuit 1, the working power of C14.The 18 pin output high level of IC4 is added to the SB3 control end of analog switch IC5 (CD4066), the SB3 closure, and power supply E provides working power by SB3 to modulating emission circuit IC3.18 pin of IC4 output high level is added to the control end of bidirectional analog switch S B2, and the SB2 closure is communicated with 9 pin of IC3 with antenna TX2.The student is exported by 3 pin of single-chip microcomputer IC4 with extension set self code signal, delivers to 5 pin of modulating emission circuit IC3, after modulation is amplified, launches by TX2.After the student sent with the extension set code signal, the student returned to " voice " operating state again with extension set.

Referring to Fig. 5, after the start, when pressing the S1 key, loudspeaker Y " toot " sound, expression has entered another operating state.Press the S2 key, have only when in " voice " operating state, loudspeaker Y can be sent " toot " sound.Press S1, during the S2 key, the 12 pin output audio pulse signals of single-chip microcomputer IC4 (AT89C2051) are delivered to power amplifier, promote the loudspeaker Y sounding.The 12 pin initial conditions of single-chip microcomputer IC4 are low level.

Below introduce the teacher and use the extension set principle with main frame identification student

Referring to Fig. 4, serve as a teacher when receiving the call signal that a certain student sends with extension set with main frame, the communication port RXD of single-chip microcomputer IC8 (10 pin) receives a string student of representative of being sent here by IC2 (TDA7021) FM reception circuit 14 pin coded pulse signal with the extension set numbering, compare with the extension set coding with 64 students of single-chip microcomputer IC8 storage, when differentiating unanimity, single-chip microcomputer IC8 exports control signal, makes corresponding LED flash, and this student is with dividing confidential enquirement during table.If this key is pressed, this student delivers to modulating emission circuit IC1 (MC2833) with 11 pin (communication port TXD) of extension set code signal by single-chip microcomputer IC8, and TX1 outwards launches by antenna.When sending the string sign indicating number, 8 pin of single-chip microcomputer IC8 become low level by high level, are added to switch S B3 control end, make the SB3 open circuit cut off audio signal.After the serial code battery has fired, 8 pin of IC8 recover high level, realize that the signal timesharing sends.If call not accepted, during not according to key letter, corresponding LED flash 30 seconds (1HZ) extinguishes automatically.

Below introduce the student and use the main frame principle with extension set identification teacher

Referring to Fig. 5, when start, the student is operated in " voice " operating state with extension set.Serve as a teacher when sending " intercommunication " control signal with main frame, the student receives the coding control signal that sends with main frame from the teacher with extension set by FM reception IC circuit 1 (TDA7021), after demodulation, export from IC1 (TDA7021) 14 pin, deliver to single-chip microcomputer IC4 (AT89C2051) 2 pin, after single-chip microcomputer IC4 decoding, if encode when inconsistent with extension set with the student, the student is uncontrolled with extension set, if with this student with extension set coding when consistent, monolithic IC4 machine executive control program realizes that the student uses main frame " intercommunication " function with extension set and teacher.

Referring to Fig. 5, single-chip microcomputer IC4 operating state is: 17 pin become the control end that high level is added to the SB3 of bidirectional analog switch I C5 by low level, and the SB3 closure is powered to modulating emission circuit IC3 by SB3.16 pin become the SB4 control end that high level is added to IC5 by low level, and the SB4 closure makes capacitor C 31 short circuits switch frequency modulation emission frequency.18 pin are the control end that high level is added to the SB2 of IC5, SB2 closure, 9 pin of connection antenna TX2 and IC3.13,14 pin output low levels, the power supply of the tuning circuit of corresponding FM reception circuit is cut off.15 pin become high level by low level, to the external tuning circuit of 5 pin (L4, C14) power supply, the change FM reception frequency of FM reception IC circuit 1.This moment, the teacher was located at " intercommunication " state with main frame S5 (teaching) key, and the teacher uses extension set with all students of host computer control, selected arbitrarily (one or more).When not needing intercommunication, only need click teacher's " intercommunication " operating key with the main frame correspondence, send the control signal of closing student's usefulness extension set " intercommunication " by the teacher with main frame, when the student received this signal with extension set, the student just reverted to the initial condition of " voice " work with extension set.

Claims

1, a kind of radio frequency wireless bidirectional phonetic teaching device, comprise that the teacher uses extension set with main frame and student, described teacher is made up of radiating circuit, receiving circuit, coding circuit, function commutation circuit and power amplifier with main frame, described student is made up of radiating circuit, receiving circuit, control circuit and the big circuit of audio interface folding and unfolding with machine, it is characterized in that:

Be serially connected with the capacitor C 15 that changes frequency in a, the crystal oscillator loop of teacher with the radiating circuit of main frame, be parallel with the shorted to earth bidirectional analog switch (SB2) that is controlled by single-chip microcomputer on this electric capacity, the radiofrequency signal output serial connection one of radiating circuit is controlled by the bidirectional analog switch (SB1) of single-chip microcomputer; Being provided with two different element circuits that receive frequency in the receiving circuit of teacher with main frame forms;

Be serially connected with the capacitor C 31 that changes frequency in b, the crystal oscillator loop of student with the radiating circuit of extension set, be parallel with the shorted to earth bidirectional analog switch (SB4) that is controlled by single-chip microcomputer on this electric capacity, the radiofrequency signal output serial connection one of radiating circuit is controlled by the bidirectional analog switch (SB2) of single-chip microcomputer; The student is provided with the tuning circuit of three groups of different frequent points with the voltage controling end (VCO) of the receiving circuit of extension set.

2, require 1 described a kind of radio frequency wireless bidirectional phonetic teaching device according to power, it is characterized in that the teacher with the playback circuitry that is provided with a controlled single-chip microcomputer (IC8) in the main frame, this playback circuitry is connected and composed successively by microphone MIC, amplifying circuit and recording playback special chip IC 7.

3, require 1 or 2 described a kind of radio frequency wireless bidirectional phonetic teaching devices according to power, it is characterized in that the teacher with the address display circuit that is provided with a controlled single-chip microcomputer (IC8) in the main frame, this display circuit by the serial decoding circuit and with coding circuit in key letter K1---the corresponding LED 1 of K64---LED64 forms.