CN201937575U

CN201937575U - USB (universal serial bus) frequency modulation transmitter

Info

Publication number: CN201937575U
Application number: CN2011200084206U
Authority: CN
Inventors: 刘思洋
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-01-11
Filing date: 2011-01-11
Publication date: 2011-08-17
Anticipated expiration: 2021-01-11

Abstract

The utility model provides a USB (universal serial bus) frequency modulation transmitter, which comprises an audio interface module, a stereo adjusting module, a frequency modulation transmitting module and a frequency modulation amplifying module which are connected sequentially. Input of digital audio signals is received by the aid of the audio interface module and adjusted into stereo analog audio signals before wireless conversion through the frequency modulation transmitting module, and then frequency modulation audio signals are outputted by the frequency modulation amplifying module.

Description

The USB frequency-modulated transmitter

Technical field

The utility model relates to a kind of electronic equipment, especially a kind of USB frequency-modulated transmitter.

Background technology

A lot of musical instrumentses all are to be connected with sound equipment by tone frequency channel wire, are not under many circumstances easily to carry out cable to connect, and also are not easy to carry, and equipment also is not easy to move.

Summary of the invention

The shortcoming of for a change above-mentioned traditional music equipment, the utility model provide a kind of USB frequency-modulated transmitter.

The utility model comprises audio interface module, stereo adjusting module, frequency modulation transmitter module, the frequency modulation amplification module, it is characterized in that, audio interface module, stereo adjusting module, frequency modulation transmitter module, the frequency modulation amplification module connects successively, receives the input of digital audio and video signals by the audio interface module, be adjusted into stereo analogue audio frequency after, carry out wireless conversion by the frequency modulation transmitter module, and through frequency modulation amplification module output frequency modulated audio signal.

The beneficial effects of the utility model are, the USB frequency-modulated transmitter can insert musical instruments at any time, and launches by wireless frequency modulation, as long as just there is the FM reception system can play out music, and equipment is easy to carry about with one, and has better flexibility and portability.

Description of drawings:

Fig. 1 is a schematic diagram of the present utility model, and Fig. 2 is the utility model electricity structure chart.

Embodiment:

As shown in Figure 1, the utility model comprises audio interface module 1, stereo adjusting module 2, frequency modulation transmitter module 3, frequency modulation amplification module 4, audio interface module 1, stereo adjusting module 2, frequency modulation transmitter module 3, frequency modulation amplification module 4 connects successively, receives the input of digital audio and video signals by audio interface module 1, be adjusted into stereo analogue audio frequency after, carry out wireless conversion by frequency modulation transmitter module 3, and through frequency modulation amplification module 4 output frequency modulated audio signals.

As shown in Figure 2, audio signal by the input of 1 pin, 22 pin after, cooperate by delivering in the blender behind preemphasis circuit, amplitude limiter circuit and the low pass filter by 21,20,19,2,3,4 pin and the external circuit of BH1417.By the oscillating circuit of the access 7.6MHz crystal oscillator of 13 pin, 14 pin input, produce the subcarrier signal of 38kHz by 200 frequency divisions.The 38kHz subcarrier is by producing the pilot signal of 19kHz behind 2 frequency divisions, L channel deducts the signal of R channel and the subcarrier of 38kHz carries out the balance modulation, and the composite signal after the modulation is by the output of 5 pin.Modulating emission circuit adopts the phase-locked loop systems of frequency stabilization.After the decoding of frequency codes process and phase demodulation of 15,16,17, the 18 pin input of BH1417, by the control signal VCO of 7 pin output LC oscillator.The high-frequency oscillating circuits that this VCO control external discrete element is formed produces the carrier signal of FM frequency modulation, and by 2 triode C9018 the composite stereo acoustical signal of 5 pin output is carried out the FM frequency modulation(FM).Signal after the modulation is input to BH1417 by 9 pin, and the radiofrequency signal after amplifying through inner radio frequency amplifier is exported by 11 pin.Signal after the output can directly be received 5,7,9,10,12 pins of launching BH1417 on the transmitting antenna and cooperate connected discrete component, constitutes the hunting of frequency and the rf modulations part of frequency modulated carrier; 13,14 pin need the crystal oscillator of external 7.6MHz, offer the needed stabilizing clocks of part such as phase demodulation, stereophonic signal modulation of BH1417 inside; 6,8 is power unit; 11 pin constitute the FM signal radiating portion with the outside element that is connected.After the 11 pin signals output of BH1417, adopt 9018 to come one-level to amplify the wireless output of back frequency modulation.

Claims

1. USB frequency-modulated transmitter, audio interface module (1), stereo adjusting module (2), frequency modulation transmitter module (3), frequency modulation amplification module (4), it is characterized in that, audio interface module (1), stereo adjusting module (2), frequency modulation transmitter module (3), frequency modulation amplification module (4) connects successively.