CN201113982Y

CN201113982Y - USB wireless audio frequency emitting set

Info

Publication number: CN201113982Y
Application number: CNU2007201722053U
Authority: CN
Inventors: 骆正伦
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-09-28
Filing date: 2007-09-28
Publication date: 2008-09-10
Anticipated expiration: 2017-09-28

Abstract

The utility model discloses a USB wireless audio frequency transmitting device, which belongs to the wireless audio frequency transmitting field and aims to solves the technical problem that an FM transmitting device in the prior art can not be applied in a USB interface. The utility model adopts the technical proposal that: the USB wireless audio frequency transmitting device is provided with the USB interface which is connected with a power module; the USB interface is also connected with a USB interface and a digital-analog conversion module which are connected with an FM stereo frequency modulation module; and the FM stereo frequency modulation module is connected with a high-frequency power amplifier transmitting module which is connected with a transmitting antenna. The USB wireless audio frequency transmitting device can simply, conveniently and highly efficiently transmit audio frequency information from the network and a computer to a player for play and is suitable for being used in household, markets and recreation areas.

Description

A kind of USB ANTENN AUDIO emitter

Technical field

The utility model relates to a kind of emitter, more particularly, relates to a kind of ANTENN AUDIO emitter that connects USB port.

Background technology

Current, along with PC to popularize with the very fast of the Internet, the propagation of multimedia information on PC has an unprecedently grand occasion; Musical information has developed storage and mode of propagation based on PC and the Internet from the storage of cassette band and disc and mode of propagation, and transmits and play with MP3 format.The radio station also from original cell site's pattern, has developed by the Internet and has propagated.In the prior art, need a kind of can the realization, the equipment that the stereo set that all has by general family is play with audio frequency information abundant on the Internet and the computer.ANTENN AUDIO transmission technology of the prior art, no matter be with " simulating " or " numeral " processing mode as Radio Transmission Technology, all be unable to do without the configuration mode that emitter of employing adds a receiving system; These principle of device and structure more complicated use very inconvenience.Also to consider the specification and the conversion of external power supply and different audio interface in use, tone frequency channel wire and receiver are to loaded down with trivial details links such as installation between the existing audio frequency apparatus and distances, and vehicle mounted MP 3 and FM reflector and the FM reflector that aims at the iPod design only concentrate on MP3 and the iPod player in the prior art, can't spread in PC and the family.

Summary of the invention

Technical purpose of the present utility model is to solve in the prior art, the ANTENN AUDIO transmitter exists and uses inconvenience, can't be applicable to the technical problem of PC USB port, provide a kind of and can the audio frequency information of enriching on the Internet and the computer be transmitted to the USB ANTENN AUDIO emitter that the family expenses stereo set is play with wireless mode by USB interface.

For realizing above technical purpose, the technical solution of the utility model is:

A kind of USB ANTENN AUDIO emitter, include shell, described shell is provided with USB interface, described USB interface is connected with power module, described USB interface is connected with USB interface and digital-to-analogue conversion module simultaneously, and described USB interface and digital-to-analogue conversion module connect FM stereo fm module; Described FM stereo fm module connects the radio frequency power amplifier transmitter module; Described radio frequency power amplifier transmitter module is connected with transmitting antenna.

Further, described USB interface and digital-to-analogue conversion module are provided with the USB interface/arbiter that connects USB port, and USB interface/arbiter is connected with control data and audio data processor; Control data and audio data processor be connected with digital analog converter (DA);

Further, FM stereo fm module is provided with preemphasis/amplitude limiter;

Further, FM stereo fm module is provided with synchronised logic device;

Further, FM stereo fm module is provided with buffer amplifier;

Further, FM stereo fm module is provided with pilot signal oscillator, frequency mixer and voltage-controlled oscillator;

Further, FM stereo fm module is provided with frequency controller;

Further, described shell is provided with LED light;

Further, described shell is provided with frequency selective switch.

In the technical solution of the utility model, insert the USB port of computer when the USB interface of the utility model USB ANTENN AUDIO emitter after, power module from the USB port of computer obtain 5 volts 500 milliamperes power supply, be that whole emitter is powered; USB interface is obtained digital audio-frequency data from the USB port of computer, and digital audio-frequency data is by USB interface and digital-to-analogue conversion module, is transported to FM stereo fm module after converting stereo audio signal to; FM stereo fm module adopts PHASE-LOCKED LOOP PLL TECHNIQUE, and a stable oscillator is provided, and stereo pilot signal compound voice audio frequency signal and convert high-frequency wireless signals to, is transported to the radio frequency power amplifier transmitter module; The radio frequency power amplifier transmitter module carries out power amplification with high-frequency wireless signals, and is transported to transmitting antenna, and transmitting antenna is transmitted to receiving system (for example broadcast receiver) with signal and receives.

Useful technique effect of the present utility model is: by a simple and practical device, will convert wireless signal to from the digital audio and video signals of USB port, and be transmitted into to receive in the home audio playback equipment and play; The utility model is with low cost, easy to use, technology maturation, easy to implement.

Description of drawings

Fig. 1 is a circuit block diagram of the present utility model; What arrow was represented among the figure is the trend of signal or power supply;

Fig. 2 is the circuit block diagram of USB interface and digital-to-analogue conversion module among embodiment of the utility model; What arrow was represented among the figure is the trend of signal;

Fig. 3 is the circuit block diagram of FM stereo fm module among embodiment of the utility model; What arrow was represented among the figure is the trend of signal;

Fig. 4 is the circuit theory diagrams of USB interface and digital-to-analogue conversion module among embodiment of the utility model;

Fig. 5 is the circuit theory diagrams of an embodiment of the utility model FM stereo fm module and radio frequency power amplifier transmitter module;

The circuit theory diagrams of another embodiment of Fig. 6 the utility model FM stereo fm module and radio frequency power amplifier transmitter module;

The last figure of Fig. 7 is the front schematic view of USB wireless launcher outward appearance, and figure below is the schematic rear view of USB wireless launcher outward appearance.

Embodiment

Present embodiment only is a better embodiment of the present utility model, does not limit maximum interest field of the present utility model.

In conjunction with the accompanying drawings 1; In an embodiment of the present utility model, be provided with USB interface, described USB interface is connected with power module 100, and described USB interface also is connected with USB interface and digital-to-analogue conversion module 101, and described USB interface and digital-to-analogue conversion module 101 connect FM stereo fm module 102; Described FM stereo fm module 102 connects radio frequency power amplifier transmitter module 103; Described radio frequency power amplifier transmitter module 103 is connected with transmitting antenna.After this device is plugged USB port, by the standard USB port provide 5 volts 500 milliamperes power supply, power module 1 is directly obtained power supply from port, after filter was noise filtering, whole device was given in power supply.

In conjunction with the accompanying drawings 2; In USB of the present utility model interface and the digital-to-analogue conversion module 101, (be called for short: arbiter 201), arbiter 201 is connected with control data and audio data processor 202 (is called for short: processor 202) to be provided with the USB interface/arbiter 201 that connects USB port; Processor 202 be connected with digital analog converter (DA) 203; Processor 202 directly reads voice data from Windows with USB audio devices agreement (USB audiodevice class specification) by arbiter 201; Processor 202 with voice data be transported to digital analog converter (DA) 203, voice data is converted into stereo audio signal (simulation signal) and send FM stereo fm module 102.

In conjunction with the accompanying drawings 3; In the utility model FM stereo fm module 102, in order to reduce the high frequency noise in the wireless transmission process, and input over and lead the problem of distortion, audio signal is passed through the processing of preemphasis/amplitude limiter 301 earlier, deliver to frequency mixer 303 again and mix, produce a main signal (L+R) and a secondary audio signal (L-R) with pilot signal (19kHz) and subcarrier signal (38kHz).Main signal, secondary audio signal add that pilot signal formed composite signal and delivered to the FM radiating circuit.Pilot signal and subcarrier signal produce with divided version by synchronised logic device 305 and pilot signal oscillator 302 respectively by crystal oscillating circuit.The FM radiating circuit has adopted phase-locked loop systems; Described phase-locked loop systems includes synchronised logic device 305, voltage-controlled oscillator 306 and buffer amplifier 307; Voltage-controlled oscillator 306 includes variable capacitance diode, and electric capacity and inductance are formed; Voltage-controlled oscillator 306 is used to realize the frequency modulation modulation, and stereo composite signal directly carries out the frequency modulation modulation by it.Oscillator signal after the frequency modulation modulation is exported through buffer amplifier 307 by oscillator 306, simultaneously also deliver to phase-locked loop circuit and carry out the phase bit comparison, once frequency surpasses the frequency that phase-locked loop is set, synchronised logic device 305 can make frequency reach stable by the means that the level of the variable capacitance diode in the oscillator 306 is adjusted.Frequency controller 304 is a logic controller, carries out tranmitting frequency with 4 plucking number sign switches and sets; Oscillator signal after the frequency modulation modulation outputs to radio frequency power amplifier transmitter module 103 by oscillator 306 through buffer amplifier 307.

In embodiment of the present utility model, radio frequency power amplifier transmitter module 103 is simple class A amplifiers, radio frequency power amplifier transmitter module 103 is the in addition power amplification of the oscillator signal of 307 outputs of the buffer amplifiers from FM stereo fm module 102, by two " π " shape LC filter and antenna match and reach the effect of harmonic wave inhibition; Flowing to antenna launches.By emitter of the present utility model, the audio signal on the host computer just can be transmitted in the atmosphere by this device, plays after the reception.

Below in conjunction with Fig. 4 the circuit theory of USB interface among the utility model embodiment and digital-to-analogue conversion module 101 and power module 100 is elaborated, in use, the USB port of computer is connected with the USB interface of this circuit, in the circuit of accompanying drawing 4, is provided with USB interface J100; Obtain power supply from the 1st pin (positive pole) and the 4th pin (negative pole) of the USB interface of this circuit.Inductance L 100, L101 and capacitor C 100 are formed filter circuit, also are the noise filtering on the power supply entire circuit power supply (V1).Audio Processing chip U100 adopts the CM-102S model chip of C-Media company; Audio Processing chip U100 is connected with the computer USB port by esd protection resistance R 100, R101, and the 7th pin of Audio Processing chip U100, the 8th pin are the voice data input port; Audio Processing chip U100 directly becomes the simulation signal to voice data by digital translation from Windows with USB audio devices agreement (USB audio device classspecification), and left and right acoustic channels is respectively from port ANL and ANR output.Crystal oscillator Y100 connects 3 and 4 pin of Audio Processing chip U100, cooperates internal oscillator circuit to provide basic running required signal source of clock for Audio Processing chip U100.When the USB interface in the circuit with after the computer USB port is connected, the 1st pin of Audio Processing chip U100 and the 18th pin output high potential are lighted indicator light LD100.The input port that the 12nd pin of Audio Processing chip U100 is controlled for the voltage volume, by voltage divider R105 and R106, can be adjusting according to different needs from the audio level of port ANL and ANR output; Left and right acoustic channels outputs to FM stereo fm module 102 and radio frequency power amplifier transmitter module 103 from port ANL and ANR respectively.

Below in conjunction with Fig. 5 the circuit theory of FM stereo fm module 102 and radio frequency power amplifier transmitter module 103 among the utility model embodiment is elaborated, in the present embodiment, stereo transmitting chip U200 has adopted the BH1417F model chip of Rohm company; The signal end of the left and right acoustic channels ANL of output and ANR is connected respectively to the 1st pin and the 22nd pin of stereo transmitting chip U200 in USB interface and digital-to-analogue conversion module 101.The time constant of preemphasis depends on capacitor C 200 and the C203 that is connected to U200 the 2nd and 21 pin.So-called " preemphasis " is that FM broadcasts in order to improve signal to noise ratio, when emission voice signal sent into before the transmitter, and the level with HFS suitably promotes in advance; Then, signal is handled through built-in frequency mixer, produces main signal (L+R), and subcarrier signal (L-R) and pilot signal 19kHz, these signals form composite signal and export from stereo transmitting chip U200 the 5th pin.Composite signal is delivered to semifixed resistor VR200 through capacitor C 206, so that adjust the degree of depth of frequency modulation modulation, avoids excessively modulation and distortion occurs.Composite signal is through compensating for frequency response circuit C207, and C210 and R211 also deliver to TP1; The input of voltage-controlled oscillator.Described voltage-controlled oscillator is mainly by variable capacitance diode D200, and inductance L 200 and capacitor C 214 are formed.By signal level variation, variable capacitance diode D200 capacitance is changed, thereby change a kind of mechanism of frequency of oscillation, composite signal is modulated by voltage-controlled oscillator frequency modulation.Frequency of oscillation is delivered to stereo transmitting chip U200 the 9th pin through match circuit C215 and R212; The input of phase-locked loop.Inner phase-locked loop circuit according to frequency controller in the 15th of stereo transmitting chip U200,16, the setting of 17 and 18 pin, frequency from stereo transmitting chip U200 the 9th pin input is compared, if incoming frequency is lower than setpoint frequency, then stereo transmitting chip U200 the 7th pin output level step-down; Otherwise if incoming frequency is higher than setpoint frequency, then stereo transmitting chip U200 the 7th pin output level uprises; In the time of identical, then level is constant.Stereo transmitting chip U200 the 7th pin is connected to low pass filter, and described filter is mainly by triode Q200, triode Q201, and capacitor C 208, resistance R 205 and capacitor C 209 are formed.The variation that then stereo transmitting chip U200 the 7th pin produces in response to the difference of incoming frequency and setpoint frequency, through low pass filter noise is removed, and deliver to variable capacitance diode D200, see through the relation of level variation and variable capacitance diode D200 volume change and frequency of oscillation, incoming frequency and setpoint frequency are reached identical numerical value.Crystal oscillator Y200 connects the 13rd pin and the 14th pin of stereo transmitting chip U200, cooperates internal oscillator circuit, for the synchronised logic device (phase-locked loop) in the stereo transmitting chip U200 provides reference frequency, as the usefulness of signal frequency split and generation setpoint frequency.Frequency of oscillation is behind the internal damping amplifier, and from the 11st pin output of stereo transmitting chip U200, by match circuit C219, R213 and L204 deliver to high-frequency amplifier circuit.High-frequency amplifier circuit is mainly by Q202, R214, and R215, C220 and L201 form.Power amplifier is through two " π " mode filters and antenna match, and frequency of oscillation is transmitted in the atmosphere.Described two " π " mode filter is mainly by C223, C224, and C225, C226, L202, L203 and L205 form.

In this example, Audio Processing chip U100 has adopted the CM-102S model chip of C-Media company, but in fact the eKA8564A model of other special audio process chip chip such as Elan company also can reach effect same; Again for example, in this example, stereo transmitting chip U200 has adopted the BH1417F model chip of Rohm company, in actual applications, the stereo transmitting chip SP1417 chip of the Wuxi little electric company of silicon power and A7303B chip (as shown in Figure 6) of AMIC or the like also can substitute; Being equal to of said chip used and replaced, and also should be included within the interest field of the present utility model.

In addition, the utility model has also proposed liquid crystal display and touch switch further are set in device, is used as the usefulness of tranmitting frequency setting.Thereby become convenient in use.

As shown in Figure 7; For realizing volume miniaturization and easy to use, this device can be designed to an etui that 80 * 20 * 11mm is only arranged, this device has a USB plug (USB port), casing 1, LED light 3 (promptly being the LD100 in the circuit) and one four s' frequency selective switch 2.The user can utilize this switch to go the frequency of selecting them to like.During use, as long as this device is inserted on the host computer, indicator light is bright can be used.Need not additional power source, also need not any driving and playout software and install.

In a word, the utility model has adopted mature technique, to have USB interface, D/A conversion circuit, FM and radiating circuit thereof now and be designed to one dexterously, and can will come from audio frequency information on the Internet and the computer convenient, efficiently and be transmitted on the normal domestic use playback equipment and play.

Claims

1. USB ANTENN AUDIO emitter, include shell, it is characterized in that: described shell is provided with USB interface, described USB interface is connected with power module, described USB interface is connected with USB interface and digital-to-analogue conversion module simultaneously, and described USB interface and digital-to-analogue conversion module connect FM stereo fm module; Described FM stereo fm module connects the radio frequency power amplifier transmitter module; Described radio frequency power amplifier transmitter module is connected with transmitting antenna.

2. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described USB interface and digital-to-analogue conversion module are provided with the USB interface/arbiter that connects USB port, and USB interface/arbiter is connected with control data and audio data processor; Control data and audio data processor be connected with digital analog converter (DA).

3. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described FM stereo fm module is provided with preemphasis/amplitude limiter.

4. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described FM stereo fm module is provided with synchronised logic device.

5. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described FM stereo fm module is provided with buffer amplifier.

6. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described FM stereo fm module is provided with pilot signal oscillator, frequency mixer and voltage-controlled oscillator.

7. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described FM stereo fm module is provided with frequency controller.

8. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described shell is provided with LED light.

9. according to the USB ANTENN AUDIO emitter of claim 1, it is characterized in that: described shell is provided with frequency selective switch.