CN100428637C - Dot frequency radio transmission and receiving circuit and device - Google Patents
Dot frequency radio transmission and receiving circuit and device Download PDFInfo
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- CN100428637C CN100428637C CNB021572895A CN02157289A CN100428637C CN 100428637 C CN100428637 C CN 100428637C CN B021572895 A CNB021572895 A CN B021572895A CN 02157289 A CN02157289 A CN 02157289A CN 100428637 C CN100428637 C CN 100428637C
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Abstract
The present invention relates to a spot frequency wireless transmitter which comprises an amplifying circuit, a crystal frequency stabilizing circuit, a radio-frequency oscillator, a frequency doubling circuit and a matched filtering network circuit, wherein accompanying sound audio current is input into the radio-frequency oscillator via the amplifying circuit and the crystal frequency stabilizing circuit, the accompanying sound audio current is then input into the frequency doubling circuit, and the accompanying sound audio current is then output from the frequency doubling circuit and transmitted to a transmitting terminal via the matched filtering network circuit. The spot frequency wireless receiver comprises an LC filtering network circuit, a high-frequency amplifying circuit, a local oscillation circuit and a mixing circuit for the crystal frequency stabilizing circuit, an intermediate frequency circuit, an FM demodulation circuit and an audio amplifying circuit, wherein the LC filtering network circuit is connected with the high-frequency amplifying circuit, and the output of a high-frequency signal and the output of the local oscillation circuit are connected with the mixing circuit. An intermediate frequency signal is obtained from the difference (or sum) of a local oscillation signal output by the mixing circuit and an external signal, the intermediate frequency is transmitted via the FM demodulation circuit, an audio signal is demodulated by the FM demodulation circuit, and the audio signal is transmitted to the transmitter and the receiver of the terminal equipment of the receiver. The device has the advantages of high signal to noise ratio, low cost, no need for high-frequency amplification, and low cost for completing spot frequency operation.
Description
One, technical field:
The present invention relates to a kind of wireless transmission receiving circuit frequently and device, relate in particular to and colour TV points of engagement transmitting set and receiver frequently, also relate to education, the transmitting set and the receiver of other occasion use of making peace.
Two, background technology:
The once popular TV infrared radio transmitter and receiver of crossing in market in those early years, because wear-type receiver volume is excessive, factors such as the overweight and fetch long price of quality, finally fail to be accepted by consumers in general, also having a factor is exactly directional problems, require have no occluder between the transmitting-receiving during use, and in a single day receiver depart from emission source, phenomenons such as sound is light, noise is big promptly can occur.
Adopt the tv wireless transmitter and receiver market of wireless receiving and dispatching mode also once fashionable for a time, the listening study that also comprises language is used and hearing examination transmitter and receiver, adopt the LC mode of oscillation owing to send part, cause the necessary tuning ability operate as normal of receiving terminal (often adopting induction to receive), user's direct impression is inconvenient, it is wide that common this radiation pattern occupies frequency range, and antenna output end does not have the harmonic filtration network, noise jamming is big, transmitting power is often bigger than normal, and LC master oscillator frequenc and harmonic wave can serious interfering TV picture and even FM broadcasting.Can also occur the phenomenon in dead band in same classroom, distortion is also big, more than is the weak point of past two types of products.
Existing scheme is mentioned the device that carries out wireless transmission and receiver with the intermediate frequency frequency range, but frequency range is limited, and can't solve the problem of a frequency.
Existing intercom also is transmitting set and receiver, still uses the circuit that transmits and receives that high frequency amplifies, and its signal to noise ratio still has the leeway of raising comparatively speaking, and it is higher to have an intercom circuit cost of duplex capability, requires emitted power big.
Three, summary of the invention:
At above-mentioned two product existing problems and the weak point of representing prior art, the present invention seeks to: the some frequency transmitting set and the receiver that provide a kind of transceiver mode still to adopt the radio propagation form, adopt the crystal frequency stabilization circuit, make the transmitting-receiving of transmitter and receiver reliable and stable, effectively suppress the interference of harmonic wave to some channel of TV and FM broadcasting, reduce transmitting power, the noise of receiver is little, the cost of circuit is low, receive well, and realize some work frequently, and the work of energy multichannel, range of application is wider.
The object of the present invention is achieved like this: point is radio transmitter frequently, comprise that strength circuit, frequency multiplier circuit, matched filter network circuit that low gain amplifying circuit, variable reactance circuit, amplification and crystal frequency stabilization circuit constitute constitute, audio signal is delivered to the variable reactance circuit after the low gain amplifying circuit amplifies, the output of variable reactance circuit is through the strength circuit modulation of amplifying and the crystal frequency stabilization circuit constitutes, be input to frequency multiplier circuit after the modulation of strength circuit, the antenna transmitting terminal is transported in frequency multiplier circuit output behind the matched filter network circuit.
Corresponding and with the point of foregoing circuit coupling wireless receiving circuit frequently, comprise LC filter network circuit, high-frequency amplifier circuit, local oscillation circuit and mixting circuit, intermediate-frequency circuit, FM demodulation circuit, audio amplifier circuit constitute, LC filter network circuit connects high-frequency amplifier circuit, the output of high-frequency signal connects mixting circuit with the output of local oscillation circuit, local oscillation circuit adopts crystal oscillating circuit, mixting circuit output intermediate-freuqncy signal, intermediate frequency connects FM demodulation circuit again, connects audio frequency amplifier again, connects electro-acoustic element at last.
Point is transmitting set frequently, comprise the low gain amplifying circuit, the variable reactance circuit, the radio-frequency oscillator that amplification and crystal frequency stabilization circuit constitute, frequency multiplier circuit, the matched filter network circuit, audio signal is delivered to the variable reactance circuit behind the low gain amplifying circuit, variable reactance circuit output injection wafer (X ') the series connection controllable impedance, the crystal frequency stabilization circuit that electric capacity constitutes, after modulating, the fundamental frequency radio-frequency oscillator that amplifies and the crystal frequency stabilization circuit constitutes is input to frequency multiplier circuit, to the antenna transmitting terminal, described frequency multiplier circuit is the 2-10 frequency multiplier circuit through the matched filter network circuit in frequency multiplier circuit output.
Match with above-mentioned transmitter, point is wireless receiver frequently, comprise LC filter network circuit, high-frequency amplifier circuit, local oscillation circuit and mixting circuit, intermediate-frequency circuit, FM demodulation circuit, audio amplifier circuit, LC filter network circuit connects high-frequency amplifier circuit, the output of high-frequency signal connects mixting circuit with the output of local oscillation circuit, and local oscillation circuit adopts crystal oscillating circuit, and poor (or and) of mixting circuit output local oscillation signal and extraneous signal exports intermediate-freuqncy signal, connect FM demodulation circuit again through intermediate-frequency circuit, demodulate audio signal, connect audio frequency amplifier again, connect receiver terminal equipment transmitter and receiver at last.
Described local oscillation circuit is the crystal frequency stabilization circuit.
Receiver LC filter network circuit filtering parameter is 49.770 narrow-band modulated.
Originally LC vibration and LC tuning circuit are all adopted in transmitting-receiving, transmission circuit of the present invention all adopts the crystal frequency stabilization, it is very reliable and stable to work together, the harmonic filtration network that the emission output adopts, effectively suppressed the interference of harmonic wave to some channel of TV and FM broadcasting, in order further to reduce transmitting power, radiating circuit is not established the power amplifier foot in receiver is well received.Receiver has adopted the single-conversion technology, and receiving sensitivity height, signal to noise ratio are little.Maximum characteristics of the present invention are to use the receiver of native system need not be tuning, and start can be received television field frame.Fundamentally solve among the kinsfolk some people and thought reading study (or rest), and a pair of like this contradiction of video disc content that another part people wants to watch TV or VCD, DVD video disc player to play.
Characteristics of the present invention are: because wireless narrow-band FM (NFM) technology has all been adopted in transmitting-receiving, adopt the crystal frequency stabilization respectively, its frequency stability reaches 10 * 10
-6, each channel spacing is 25kHz, can hold 40 frequencies (or claiming 40 users) in the 1MHz, has saved limited frequency resource.With regard to sending part, television audio signals is by television transmission machine and receiver jack or the taking-up of video disc player audio jack, being added to the strength circuit behind the audio signal process variable reactance circuit modulates, the fundamental frequency of supposing the strength circuit is 16.590MHz, through the carrier frequency after 3 frequencys multiplication is 49.770MHz, in order to obtain bigger emission amounts of frequency offset, must be with the lifting of 16.590MHz fundamental frequency.After 3 frequency multiplier circuit frequencys multiplication, the emission maximum frequency deviation can reach 9kHz.Filter network is used for the harmonic wave deal after the filtering frequency multiplication specially, and carrier frequency is passed through smoothly, and this network also possesses the function with the antenna matched well simultaneously.It is low and communication effect good that the present invention is used for the cost of duplexing intercommunication, and circuit block diagram as shown in Figure 1.
Receiver is used for receiving the 49.770MHz narrow-band FM signal that has information specially, radiofrequency signal is earlier through the LC filter network, carrying out the one-level high frequency then amplifies, high-frequency signal after the amplification is delivered to mixting circuit and is carried out mixing, poor (or and) of local oscillation signal and extraneous signal draws the 455kHz intermediate-freuqncy signal, the 455kHz intermediate frequency is again via FM demodulation circuit, demodulate audio signal, this signal may be a television field frame, also may be language or the music signal in the video disc player video disc, by audio frequency amplifier, send to receiver terminal equipment transmitter and receiver at last.The present invention makes the transmitting-receiving of transmitter and receiver reliable and stable, effectively suppress the interference of harmonic wave to some channel of TV and FM broadcasting, the signal to noise ratio height of complete machine, cost is low, need not amplify by high frequency, can adjust to not limited channel, the especially low-cost some problem frequently that solved can be transmitted into a public domain and use shared multichannel resource.Leading indicator is as follows:
A. radiating portion:
2. tranmitting frequency: 49MHz or assigned frequency, 2. transmitting power :≤10m or≤300mW, 3. launch frequency deviation: 9kHz, 4. frequency stability: 10 * 10
-6, 5. harmonic wave suppresses: 〉=-40dB, 6. modulation system: narrow-band FM, 7. electrical source consumption :≤10mA, 8. supply voltage: 3V.
B. receiving unit:
1. receive frequency: 49MHz or assigned frequency, 2. receiving sensitivity :≤1.5 μ V, 3. frequency stability: 10 * 10
-6, 4. electrical source consumption :≤10mA, 5. antenna form: built-in, 6. audio frequency output: 〉=20mW.
Four, description of drawings:
Fig. 1 is a transmitter block diagram of the present invention
Fig. 2 is a receiver block diagram of the present invention
Fig. 3 is transmitter circuitry figure of the present invention
Fig. 4 is receiver circuit figure of the present invention
Five, embodiment:
As shown in Figure 3, the modulation that radiating portion is mainly manufactured by motorola inc, mixing, amplifying chip constitutes, be U1, model is MC2833 or close model, it is little that this chip has power consumption, characteristics such as frequency modulation is wide, audio frequency is connected into by capacitor C 18,4 of U1, there is an amplifying circuit 5 pin inside, after amplifying a little respectively by R5, C16, its inside of 3 pin that R4 delivers to this chip is provided with the variable reactance circuit, be provided with element formations 3 such as variable capacitance diode in the variable reactance circuit, 1 pin to U1, by 15,16 pin internal circuits have constituted the crystal oscillator frequency stabilization circuit, the fundamental frequency of selecting for use is the wafer of 16.590M, can certainly select the wafer of fundamental frequency for use, make its channel that allows at frequency management through frequency vibration or double-frequency oscillation and that send, controllable impedance of connecting or electric capacity T1 with wafer X at higher 50-80M, C1 can regulate the frequency of frequency stabilization, can certainly use tunable capacitor, the frequency behind frequency multiplier circuit is exactly the frequency that receiver receives.Because the frequency modulation narrow (being approximately 2-3K) of fundamental frequency, tranmitting frequency is low, therefore can not send as tranmitting frequency, must be through several times frequency multiplier circuit frequently, present embodiment is chosen treble frequency, also can use the 2-10 frequency multiplication, frequency tripling improves tranmitting frequency, regulate T2, C8 can regulate frequency multiplication, the emission frequency deviation increases, make is that not too practical frequency deviation is very useful originally, series inductance L1, the matched filter network of formations such as L2 and shunt capacitance C11 is used for suppressing and the irrelevant clutter composition of transmission frequency, launch by antenna then, the matched filter network harmonic wave suppresses generally to reach-more than the 40db, the dominant frequency of the totally level and smooth and 49.770M output amplitude maximum, launch by antenna through C13.The top of circuit is power supply and indicator light.The formation of circuit all has frame of broken lines to provide.
As shown in Figure 4, in the receiver circuit: mainly modulation, mixing, the amplification chip U1 that is manufactured by motorola inc constitutes, model is MC3361BP or close model, with said chip generally be paired, after antenna received the radio frequency of 49.770M, delivering to the frequency selection circuit that is made of T1, C2 through C1 was LC filter network circuit, with the RF signal that receives, the high-frequency amplifier circuit that the warp let-off is made up of TR1, TR2, resistance R
0R3 is biasing resistor, L is the load of TR2, the direct current biasing power supply is provided again simultaneously, C7 input RF high-frequency level, equally, U1 is also put and demodulator circuit in the narrow-band FM of low-power consumption among the figure, comprising the local oscillator mixing, separate the mediation voicefrequency circuit, crystal oscillator X and C13, C14, C15 constitutes local oscillator and mixing, frequency changer circuit, the 455K intermediate-freuqncy signal of mixing frequency conversion gained intermediate-frequency circuit in U1 amplifies, through the bandwidth filtering of FIL intermediate-frequency filter after among the U1 6,7, the demodulation of frequency discriminator circuit that 8 pin constitute, wherein 8 pin connect electric capacity and inductance T3 in parallel, this is for optimizing the quadrature network of audio frequency output, 9 of U1,10,11 pin inside are provided with audio amplifier circuit, and 9 pin are connected transmitter and receiver or loud speaker SP through audio frequency filtering with emitter follower TR3.
The attaching of this invention, Assembling Production are tuning through high frequency signal generator, 100MHz ondograph, get final product after the test, and all devices of the present invention are device commonly used.
Certainly, this device realizes that tuning method and apparatus is very convenient: carry out the radio frequency rate of readjusting the distribution that variable inductance or electric capacity carry out tranmitting frequency at the transmitter crystal frequency stabilization circuit, the local oscillation circuit of corresponding receiver is with variable capacitance or the tuning reception of variable inductance, guarantee the same frequency of transmitting-receiving, these are prior art.The scope that does not exceed the application.
In order to guarantee transmitting power, operating voltage, the transmitting terminal that can improve emission add power amplifier in addition, can satisfy the campus about 1W and to the needs of making peace, these all do not exceed the application's scope as transmitting power is brought up to.
Claims (8)
1, frequency transmitting set, it is characterized in that comprising strength circuit, frequency multiplier circuit, the matched filter network circuit of low gain amplifying circuit, variable reactance circuit, amplification and crystal frequency stabilization circuit formation, audio signal is delivered to the variable reactance circuit after the low gain amplifying circuit amplifies, the output of variable reactance circuit is through the strength circuit modulation of amplifying and the crystal frequency stabilization circuit constitutes, be input to frequency multiplier circuit after the modulation of strength circuit, the antenna transmitting terminal is transported in frequency multiplier circuit output behind the matched filter network circuit.
2,, it is characterized in that constituting the crystal frequency stabilization circuit by crystal oscillator (X ') series connection controllable impedance, electric capacity by the described transmitting set frequently of claim 2.
3, by the described transmitting set frequently of claim 2, it is characterized in that described frequency multiplier circuit is the 2-10 frequency multiplier circuit.
4, by the described transmitting set frequently of claim 2, it is characterized in that amplification and crystal frequency stabilization circuit, frequency multiplier circuit adopt narrow-band FM emission special chip (U1), audio frequency is connected into chip by electric capacity (C18), 1,15,16 pin internal circuits of chip (U1) have constituted the crystal oscillator frequency stabilization circuit, and wafer tandem is between 1,16 pin.
5, frequency wireless receiver, comprise LC filter network circuit, high-frequency amplifier circuit, local oscillation circuit and mixting circuit, intermediate-frequency circuit, FM demodulation circuit, audio amplifier circuit, it is characterized in that LC filter network circuit connects high-frequency amplifier circuit, the output of high frequency amplifying signal connects mixting circuit with the output of local oscillation circuit, local oscillation circuit adopts crystal oscillating circuit, the intermediate-freuqncy signal of the difference of mixting circuit output local oscillation signal and extraneous signal, connect FM demodulation circuit again through intermediate-frequency circuit, connect audio amplifier circuit again, connect electro-acoustic element at last.
6, by the described wireless receiver frequently of claim 5, it is characterized in that local oscillation circuit and mixting circuit, intermediate-frequency circuit, FM demodulation circuit is made of low-power consumption narrow-band FM intermediate level circuit chip (U1), crystal oscillator (X ') and electric capacity (C13, C14, C15) with 1 of chip (U1), 2 pin connect and compose local oscillator and mixting circuit, the intermediate-freuqncy signal of mixing output is amplified through the intermediate-frequency circuit of chip (U1), connect the intermediate-frequency filter bandwidth filtering of peripheral hardware, connect in chip (U1) 6 again, 7, the FM demodulation circuit demodulation that 8 pin frequency-discriminating circuits constitute, 9 of chip (U1), 10,11 pin inside are provided with audio frequency filtering and amplifying circuit.
7, by the described wireless receiver frequently of claim 6, it is characterized in that 8 pin connect electric capacity and inductance (T3) in parallel in the chip (U1), as the quadrature network of optimizing audio frequency output.
8, by the described wireless receiver frequently of claim 6, it is characterized in that 9 pin are connected electro-acoustic element through audio frequency filtering with emitter follower (TR3) in the chip (U1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021572895A CN100428637C (en) | 2003-03-19 | 2003-03-19 | Dot frequency radio transmission and receiving circuit and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021572895A CN100428637C (en) | 2003-03-19 | 2003-03-19 | Dot frequency radio transmission and receiving circuit and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1533037A CN1533037A (en) | 2004-09-29 |
| CN100428637C true CN100428637C (en) | 2008-10-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021572895A Expired - Fee Related CN100428637C (en) | 2003-03-19 | 2003-03-19 | Dot frequency radio transmission and receiving circuit and device |
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| Country | Link |
|---|---|
| CN (1) | CN100428637C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101510785B (en) * | 2008-02-15 | 2013-02-27 | 财团法人工业技术研究院 | Circuit and method for adjusting signal bandwidth |
| CN113259021B (en) * | 2021-04-30 | 2023-06-02 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Portable automatic receiving and transmitting testing device for aviation radio station |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1173768A (en) * | 1996-08-13 | 1998-02-18 | 马绍庸 | Coincidence quasi duplex centre-less frequency division multiple address and noise-resistance carrier communication system |
| CN2506026Y (en) * | 2001-11-02 | 2002-08-14 | 昆盈企业股份有限公司 | Radio transmitting circuit with adjustable radio frequency transmission power |
| CN2590286Y (en) * | 2002-12-30 | 2003-12-03 | 熊猫电子集团有限公司 | Dot frequency wireless transmitter and receiver |
-
2003
- 2003-03-19 CN CNB021572895A patent/CN100428637C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1173768A (en) * | 1996-08-13 | 1998-02-18 | 马绍庸 | Coincidence quasi duplex centre-less frequency division multiple address and noise-resistance carrier communication system |
| CN2506026Y (en) * | 2001-11-02 | 2002-08-14 | 昆盈企业股份有限公司 | Radio transmitting circuit with adjustable radio frequency transmission power |
| CN2590286Y (en) * | 2002-12-30 | 2003-12-03 | 熊猫电子集团有限公司 | Dot frequency wireless transmitter and receiver |
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| Publication number | Publication date |
|---|---|
| CN1533037A (en) | 2004-09-29 |
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Granted publication date: 20081022 Termination date: 20110319 |