CN2248426Y

CN2248426Y - Micro-wireless earphone

Info

Publication number: CN2248426Y
Application number: CN 95229184
Authority: CN
Inventors: 辜允宁
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-21
Filing date: 1995-12-21
Publication date: 1997-02-26
Anticipated expiration: 2005-12-21

Abstract

The utility model relates to a micro-wireless earphone, which is composed of a transmitter and a receiver, wherein, a transmitter circuit is mainly composed of a transistor amplifier and an LC transmitting circuit; a transmitting signal of an L-C circuit is controlled by an input signal of a base electrode of a triode; a receiver circuit is mainly formed by that after an LC tuned circuit receives a signal, TDA7021T generates a sound-driving small signal; the sound-driving small signal is amplified by TDA7050T to be sent to the earphone; the TDA7021T simultaneously can receive an 88MHz-108MHz frequency-modulated signal. The utility model uses a large scale integrated circuit to replace the conventional discrete device circuit, consequently realizing good sound quality and various functions.

Description

The micro radio earphone

The utility model belongs to a kind of miniature emission, receiving system, relates to a kind of micro radio earphone that uses on television set or recorder.

Existing wireless stereophone product on the present domestic market.These products mostly are non-recreational use greatly, generally are exclusively used in language learning and deaf hearing aid, thereby also be far from being high-quality acoustics and broad range.These products adopt the combinational circuit of common discrete component and integrated circuit simultaneously, and circuit design is out-of-date, function singleness, reliability is low, and volume is bigger, and sensitivity is low, poor anti-interference can not satisfy the demand of study, hearing aid, the requirement that does not more reach music entertainment well.Also some is used for the earphone of the recreational use of TV, sound equipment, and these earphones mostly are wired earphone greatly.Be with this earphone to listen to program and can not harass other people.But the phone-holder of this earphone must be sitting near TV or the sound equipment, and its spacing is controlled within the length range of earphone connecting line from strictness, so extremely inconvenient.Also have a kind of infrared wireless-earphone, though this earphone can be accomplished " wireless " transmitting signal, be the radio transmission of orthoscopic between emission and receiver, run into the barrier of body of wall and so on, then receiver can't received signal.

The purpose of this utility model is the micro radio earphone of a kind of recreational use of design, and it utilizes wireless transmission and receiving system, makes earphone reach " wireless ", and guarantees earphone tonequality grace.

The purpose of this utility model realizes by following scheme: the micro radio earphone is made up of transmitter, receiver, connecting line, " I " type, " L " type plug and earphone etc.In the described transmitter, the transistor base stage connects the television signal source by connecting line and plug, and its collector electrode is connected with the tuning radiating circuit of the LC that is made up of inductance, electric capacity and tunable capacitor; In the described receiver, connect a tuning circuit of forming by inductance, electric capacity and tunable capacitor by the input of frequency modulation monolithic receiver circuit, its output connects the input of integrated of low pressure stereophone power amplifier, and this power amplifier output connects an end of solenoid, and the other end of coil connects stereophone.

In the utility model, owing to inserted the tuning radiating circuit of LC in the transistor collector of transmitter, the intensity that is transmitted is subjected to the control of base input signal, therefore, the amplifying signal of transmitter emission does not almost have distortion, like this, provides basic guarantee for receiving graceful tonequality.In receiver circuit, used the integrated chip of TDA7021T frequency modulation monolithic receiver circuit to handle the electromagnetic signal that the LC tuner receives, because the use of this chip has replaced the FM circuit of traditional semi-conductor discrete device, overcome the low shortcoming of reliability of discrete device, avoid the device ghost effect between the discrete device, fundamentally guaranteed the anti-environmental interference power that this chip is very high.This TDA7021T high-quality output signal is passed through the amplification of low-voltage stereophone amplifirer again, sends into earphone, makes signal undistorted, bandwidth, and tonequality is good.In addition, the frequency modulation function that T DA7021T integrated package has makes the signal that receiver not only can receiver/transmitter, also can accept the fm broadcast signal of 88MHZ-108MHZ, and this peculiar function still belongs to the first time in the earphone system at home.This micro radio earphone volume is little simultaneously, the power consumptive province, and acoustics is good, and tonequality is simple and honest, and graceful true to nature, volume is powerful, and the range broadness had both just had barrier (for example: body of wall) also can not influence audibility between emission and the receiver in 15 meters scopes.

Fig. 1 is the electrical schematic diagram of transmitter in the utility model

Fig. 2 is the electrical schematic diagram of receiver in the utility model

Fig. 3 is the key diagram of the utility model user mode

Be described as follows below in conjunction with drawings and Examples:

In the transmitter circuitry of Fig. 1, the base stage of transistor 1 is by the signal source of plug and connecting line connection television set, and its collector electrode is connected with by inductance 2, electric capacity 3, the tuning radiating circuit of LC that tunable capacitor 4 is formed.Its intensity that transmits is subjected to the accurate control of base input signal.Though this circuit is the discrete device circuit, function is very strong, and cost is low again, and is very practical.

In the receiver circuit of Fig. 2, the input of frequency modulation monolithic receiver circuit 5 (TDA7021T) (four, five pins) connects one by inductance 6, electric capacity 7, the tuning circuit that tunable capacitor 8 is formed, above-mentioned inductance, electric capacity and tunable capacitor are connected in parallel between four, five pins of this frequency modulation monolithic receiver circuit, also be connected with another lc circuit on its five pin, they are connected in parallel by inductance 9 and electric capacity 10 and form, the other end of this lc circuit and control switch 11 join, other end connection+3V the power supply of switch 11 is equipped with mains switch 12 on the DC power supply.During use, close up mains switch 12, disconnect control switch 11, but the signal sent of integrated circuit receiver/transmitter then; Close up switch 11, then integrated circuit (IC) chip also can receive the fm broadcast signal of 88MHZ-108MHZ.Because this chip adopts advanced semiconductor integrated circuit manufacturing, die package is good, be subject between environmental parameter influence, poor reliability, device unfavorable factors such as the distributed constant effect is obvious thereby overcome traditional discrete device combinational circuit, the output signal that produces by this chip is almost without any distortion and distortion.Signal is sent into the input (two pins) of low-voltage stereophone amplifirer 13 (TDA7050T) from the 14 pins output of this chip.This chip signal output frequency band is very wide, and its good amplification effect is that the power amplifier of traditional small-sized amplifier overlap joint is incomparable.Through six, the seven pins output of the signal after its amplification by this chip, connect solenoid 14, the other end of solenoid connects earphone 15.

In Fig. 3, " I " type plug on the connecting line 16 17 to be inserted the jack of transmitter 18, and " L " type plug 17 is inserted television set earphone delivery outlet 19, this moment, television set was with silent.The tuning turn-knob 20 of transmitter is transferred between the 92-102MHZ, and (that is: the tuning radiating circuit of the LC of transmitter) television audio signals emits by transmitter 18.Again one " L " type plug on another connecting line 16 17 is inserted receiver 21, the phone-holder puts on the earphone 15 on the connecting line, closes and disturbs mains switch 12, and with control switch 11 disconnections, rotation tuning turn-knob 22, (that is: the LC tuning circuit on the receiver) is till receiving clear sound.This receiver is the optimum reception distance in 15 meters in transmitter.When utilizing receiver to make broadcast receiver, control switch 11 can be closed up rotation tuning turn-knob 22, FM broadcasting that can uppick 88MHZ-108MHZ.

Above-mentioned micro radio earphone also can be used for transmitting and receiving the sound equipment that cassette recorder or other stereo set send, and therefore has multifunctionality.

Claims

1, a kind of micro radio earphone, it is made up of transmitter, receiver, connecting line, " L " type, " I " type plug and earphone etc., it is characterized in that: the base stage of the transistor in the described transmitter circuitry (1) connects the television signal source by plug (17) and connecting line (16), the tuning radiating circuit of LC that its collector electrode connection one is made up of inductance (2), electric capacity (3), tunable capacitor (4); The tuning circuit that the input connection one of the frequency modulation monolithic receiver circuit (5) in the described receiver circuit is made up of inductance (6,9), electric capacity (7,10) and tunable capacitor (8), its output connects low pressure stereophone power amplifier (13), the output of this integrated circuit connects solenoid (14), and the other end of solenoid connects earphone (15).

2, micro radio earphone according to claim 1, it is characterized in that: be connected with the tuning circuit that is connected in parallel and forms by inductance (6), electric capacity (7), tunable capacitor (8) between four, five pin inputs of frequency modulation monolithic receiver circuit (5), also be connected with a lc circuit on its five pin, they are connected in parallel by inductance (9) and electric capacity (1 0) and form, and the other end of this lc circuit connects control switch (11), and the other end of switch (11) connects DC power supply.