CN202841457U

CN202841457U - Frequency-modulated wireless microphone with single battery

Info

Publication number: CN202841457U
Application number: CN 201220570027
Authority: CN
Inventors: 刘喆
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-01
Filing date: 2012-11-01
Publication date: 2013-03-27
Anticipated expiration: 2022-11-01

Abstract

The utility model provides a frequency-modulated wireless microphone with a single battery. The frequency-modulated wireless microphone is characterized by comprising the 1.5V battery, an acoustical signal input circuit, a triode biasing circuit, a high-frequency oscillating circuit and a high-frequency signal emitting circuit. The frequency-modulated wireless microphone is provided with the single battery and a single NPN triode, and the oscillating frequency of the high-frequency oscillating circuit is changed to implement wave frequency modulation; and the high-frequency oscillating circuit adopts the single NPN triode, so that no involving and interference are brought to the circuit from a previous stage and a following stage, and the frequency of the high-frequency oscillating circuit is stable. The frequency-modulated wireless microphone is applicable to transmission of audio signals with a high requirement on fidelity of a wireless headset and the like, and can be used in activities such as aided teaching or karaoke in a large classroom. The frequency-modulated wireless microphone has the characteristics of being simple in circuit structure and stable in high oscillating frequency, being capable of achieving a transmitting distance up to 25 meters, being low in electricity consumption and manufacturing cost, and the like.

Description

Single battery frequency modulation type wireless microphone

Technical field

The utility model belongs to electronics and communication technique field, is about a kind of single battery frequency modulation type wireless microphone.

Background technology

The utility model adopts single battery, single NPN type triode, realizes frequency-modulated wave by the frequency of oscillation that changes high-frequency oscillating circuits.Because circuit only uses single NPN type triode, so circuit can not be subjected to involving and disturbing of front and back level, so that the frequency of high-frequency oscillating circuits is highly stable.The utility model is suitable for the audio signal transmission that the fidelity such as wireless headset is had relatively high expectations, and can be used at lyceum the activities such as aided education or Karaoke.Single battery frequency modulation type wireless microphone has the characteristics such as circuit structure is simple, and higher-order of oscillation frequency stabilization, transmitting range reach 25 meters, power consumption is few, the making basis is low.When DC power supply was used two whose power supplieds instead, the transmitting range of this wireless microphone can reach 80m.

Below describe single battery frequency modulation type wireless microphone described in the utility model related correlation technique content in implementation process in detail.

The utility model content

Goal of the invention and beneficial effect: the utility model adopts single battery, single NPN type triode, realizes frequency-modulated wave by the frequency of oscillation that changes high-frequency oscillating circuits.Because circuit only uses single NPN type triode, so circuit can not be subjected to involving and disturbing of front and back level, so that the frequency of high-frequency oscillating circuits is highly stable.The utility model is suitable for the audio signal transmission that the fidelity such as wireless headset is had relatively high expectations, and can be used at lyceum the activities such as aided education or Karaoke.Single battery frequency modulation type wireless microphone has the characteristics such as circuit structure is simple, and higher-order of oscillation frequency stabilization, transmitting range reach 25 meters, power consumption is few, the making basis is low.When DC power supply was used two whose power supplieds instead, the transmitting range of this wireless microphone can reach 80m.

The circuit working principle: single battery frequency modulation type wireless microphone is comprised of elements such as Electret condenser microphone MIC and NPN type triodes, and high-frequency oscillating circuits is comprised of peripheral cells such as NPN type triode VT1, higher-order of oscillation coil L1, capacitor C 3, capacitor C 4.Electret condenser microphone MIC becomes voice signal into tone currents, be coupled to the base stage of NPN type triode VT1 by electrochemical capacitor C1, tone currents is modulated the high frequency constant amplitude oscillating voltage, through the high-frequency signal of ovennodulation by capacitor C 5, by transmitting antenna ATX to external radiation.The biasing resistor R2 of NPN type triode VT1, resistance R 3 can make the more stable work of NPN type triode VT1 for exchanging negative-feedback circuit.Higher-order of oscillation coil L1 and oscillating capacitance C4 are determining frequency of oscillation, adjust the higher-order of oscillation coil L1 number of turn or spacing and can change higher-order of oscillation frequency.Resistance R 1 is the Electret condenser microphone MIC adaptive resistance of powering.

Technical characterictic: single battery frequency modulation type wireless microphone, it comprises 1.5V battery, voice signal input circuit, triode biasing circuit, high-frequency oscillating circuits and high-frequency signal radiating circuit, it is characterized in that:

The voice signal input circuit: it is comprised of Electret condenser microphone MIC, resistance R 1, electrochemical capacitor C1, the end of the output D connecting resistance R1 of Electret condenser microphone MIC and the negative pole of electrochemical capacitor C1, the metal shell S of Electret condenser microphone MIC links to each other with circuit ground GND, the anodal VCC of the other end connection circuit of resistance R 1, the positive pole of electrochemical capacitor C1 connects the base stage of NPN type triode VT1;

The triode biasing circuit: it is comprised of NPN type triode VT1 and resistance R 2, the end of the base stage connecting resistance R2 of NPN type triode VT1, the anodal VCC of the other end connection circuit of resistance R 2;

High-frequency oscillating circuits and high-frequency signal radiating circuit: it is by NPN type triode VT1, higher-order of oscillation coil L1, oscillating capacitance C4, capacitor C 2, negative feedback capacitor C 3, negative feedback resistor R3, coupling capacitance C5 and transmitting antenna ATX form, the collector electrode of NPN type triode VT1 and the end of higher-order of oscillation coil L1, the end of oscillating capacitance C4, one end of negative feedback capacitor C 3 links to each other with the end of coupling capacitance C5, the anodal VCC of the other end of higher-order of oscillation coil L1 and the other end connection circuit of oscillating capacitance C4, antenna ATX is penetrated in the other end sending and receiving of coupling capacitance C5, the emitter of NPN type triode VT1 and the other end of negative feedback capacitor C 3, the end of negative feedback resistor R3 links to each other with an end of capacitor C 2, the anodal VCC of the other end connection circuit of capacitor C 2, the other end of negative feedback resistor R3 links to each other with circuit ground GND.

1.5V the positive pole of battery links to each other with circuit anode VCC, the negative pole of 1.5V battery links to each other with circuit ground GND.

Description of drawings

Accompanying drawing 1 is the embodiment circuit working schematic diagram that the utility model provides a single battery frequency modulation type wireless microphone.

Embodiment

According to circuit working schematic diagram and the description of drawings of the wireless microphone of single battery frequency modulation type shown in the accompanying drawing 1, and implement to realize the utility model according to the described components and parts specification requirement of embodiment.

The selection of components and parts and technical parameter thereof

VT1 is NPN type triode, selects the middle power NPN type triodes such as 2SC9018, requires characteristic frequency fT greater than 300MHz, but the too high stability that can affect the circuit modulating frequency of characteristic frequency fT, require β 〉=110, also can select the higher high-frequency triode of characteristic frequency fT, as: 3DG80 etc.;

MIC is Electret condenser microphone, and Electret condenser microphone MIC should select the microphone of two ends output type, and its drain D is audio signal output end, connection circuit ground GND after the metal shell of Electret condenser microphone links to each other with source S; It is output that field effect transistor is connected into drain D, is conducive to improve the voltage gain of output signal, and the sensitivity of Electret condenser microphone is increased; Require the shell ends S connection circuit ground GND of Electret condenser microphone MIC for the anti-interference that improves circuit; The available model of Electret condenser microphone MIC is the CM-18W type;

It is 1/8W metalfilmresistor or fixed carbon resister that resistance is selected power, and the resistance of resistance R 1 is 200 Ω; The resistance of resistance R 2 is 36K Ω; The resistance of resistance R 3 is 36 Ω;

C1 is electrochemical capacitor, and capacity is 1 μ F/10V; C2～C5 is the high frequency Leaded Ceramic Disc Capacitor of good stability, and the capacity of C2 is 68PF; The capacity of C3 is 6PF; The capacity of C4 is 36PF; The capacity of C5 is 6PF.

Circuit production main points and circuit debugging

The making of higher-order of oscillation coil L1: on diameter ￠ 5mm spiral bit staight shank, with the flat tread flaking behind 5 circles of the enamelled wire of ￠ 0.5mm, plate scolding tin scrape off the coat of paint at coil two ends with pocket knife after;

Transmitting antenna ATX is with 1 long 0.3m telescopic antenna, or with the flexible conductor of long 0.5m, the end of transmitting antenna ATX is welded on the printed circuit board (PCB), and the other end of ATX naturally droops;

Before making, measure the performance of each element with universal instrument, each ceramic disc capacitor is preferably measured capacitance with capacitance meter; The static of NPN type triode VT1 when as far as possible reducing welding, heat are installed at last to the infringement of triode, during plug-in mounting component pin as far as possible short, as far as possible near circuit board;

The total current of single battery frequency modulation type wireless microphone illustrates the circuit working normal about 10mA, if operating current is excessive or too small all undesired, should check that element has the phenomenons such as error-free weldering, rosin joint, short circuit;

When shelves measure between the base stage of NPN type triode VT1 and the emitter voltage should＞0.75V, with two terminal shortcircuits of higher-order of oscillation coil L1 once, voltage should change to some extent between the base stage of NPN type triode VT1 and the emitter, and this explanation high-frequency oscillating circuits is started working;

If still can not receive sound in the whole frequency range of 88～108MH, then should stir a little higher-order of oscillation coil L1, only need push or dwindle the distance between the every circle of higher-order of oscillation coil L1 aside, careful especially during adjustment; Still do not prove effective if adjust the degree of tightness of higher-order of oscillation coil L1, then higher-order of oscillation coil L1 should be welded increase or reduce half turn, the rear higher-order of oscillation coil L1 that again burn-ons proceeds to adjust, until can receive clear sound;

Then pull open gradually the distance between wireless microphone and the FM receiver, until distance when reaching 25m, still can be received clearly till the voice signal.

Claims

1. single battery frequency modulation type wireless microphone, it comprises 1.5V battery, voice signal input circuit, triode biasing circuit, high-frequency oscillating circuits and high-frequency signal radiating circuit, it is characterized in that:

The voice signal input circuit is comprised of Electret condenser microphone MIC, resistance R 1, electrochemical capacitor C1, the end of the output D connecting resistance R1 of Electret condenser microphone MIC and the negative pole of electrochemical capacitor C1, the metal shell S of Electret condenser microphone MIC links to each other with circuit ground GND, the anodal VCC of the other end connection circuit of resistance R 1, the positive pole of electrochemical capacitor C1 connects the base stage of NPN type triode VT1;

The triode biasing circuit is comprised of NPN type triode VT1 and resistance R 2, the end of the base stage connecting resistance R2 of NPN type triode VT1, the anodal VCC of the other end connection circuit of resistance R 2;

High-frequency oscillating circuits and high-frequency signal radiating circuit are by NPN type triode VT1, higher-order of oscillation coil L1, oscillating capacitance C4, capacitor C 2, negative feedback capacitor C 3, negative feedback resistor R3, coupling capacitance C5 and transmitting antenna ATX form, the collector electrode of NPN type triode VT1 and the end of higher-order of oscillation coil L1, the end of oscillating capacitance C4, one end of negative feedback capacitor C 3 links to each other with the end of coupling capacitance C5, the anodal VCC of the other end of higher-order of oscillation coil L1 and the other end connection circuit of oscillating capacitance C4, antenna ATX is penetrated in the other end sending and receiving of coupling capacitance C5, the emitter of NPN type triode VT1 and the other end of negative feedback capacitor C 3, the end of negative feedback resistor R3 links to each other with an end of capacitor C 2, the anodal VCC of the other end connection circuit of capacitor C 2, the other end of negative feedback resistor R3 links to each other with circuit ground GND.

2. single battery frequency modulation type wireless microphone according to claim 1, it is characterized in that: the positive pole of 1.5V battery links to each other with circuit anode VCC, and the negative pole of 1.5V battery links to each other with circuit ground GND.