CN2657995Y

CN2657995Y - Vehicle FM broadcast device

Info

Publication number: CN2657995Y
Application number: CN 200320117367
Authority: CN
Inventors: 徐忠
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-27
Filing date: 2003-10-27
Publication date: 2004-11-24
Anticipated expiration: 2013-10-27

Abstract

The utility model discloses a vehicle FM broadcast device, which comprises an audio broadcast equipment which generates audio source signal, a vehicle FM radio and a loudspeaker, and is characterized in that a FM RF modulator is further comprised. The FM RF modulator is consisting of an audio signal input circuit, an audio signal processing and RM modulation circuit, an RF amplification and emission circuit, and a power supply circuit which are electrically connected. A signal output antenna of the RF amplification and emission circuit is connected with a ground input terminal of an audio signal by a signal emission output end through conductive wire. An inductor L1 is connected between the ground input terminal of the audio signal and a power supply ground of the circuit. A power supply 12V of a smoke lighter of the car is used as an input power supply of the power sully circuit. The power supply is filtered by an LC filtering circuit, and then output to an input end of a voltage regulator. The output power supply of the voltage regulator is used as the working power supply. The utility model has the advantages that a plurality of displayers of MD and MP3 etc can be broadcasted by the original car audio and the selection of broadcasting audio source is increased.

Description

Vehicle-mounted frequency modulation playing device

Technical field

The utility model relates to a kind of vehicle-mounted frequency modulation playing device, belongs to vehicle audio.

Background technology

Present stereophonic signal carries out FM and is modulated at the existing application in field such as Radio earphone, but be applied in the on-vehicle acoustic apparatus, stereophonic signal is launched by FM frequency modulation, the form of playing by vehicle-mounted radio does not also have again, cause except that the original sound equipment of automobile, other sound signal can't be play on auto audio equipment, resembles players such as MD, MP3 and just can't utilize original auto audio equipment to play, thereby lacked the selection of playing source of sound.

Summary of the invention

The purpose of this utility model is at above-mentioned demand and development product, and it is launched signal modulation process by a purpose made FM frequency-modulated transmitter by the stereophonic signal with various audiogenic device outputs, receives by vehicle-mounted radio and plays; And by the particular design to antenna, the appearance effects of having avoided antenna to bring by the special design to power supply, has improved reliability, the safety of power supply.

The purpose of this utility model is achieved in that a kind of vehicle-mounted frequency modulation playing device, comprise the audio-frequence player device that produces sound source signal, vehicle-mounted FM radio receiver, loud speaker, it is characterized in that: also have a FM radio-frequency modulator, the FM radio-frequency modulator is made up of sound signal input circuit, Audio Signal Processing and FM modulation circuit, radio frequency amplification and transmission circuit, power circuit, is electrically connected between them.

Above-mentioned vehicle-mounted frequency modulation playing device, it is characterized in that: radio frequency amplifies and the signal output antenna of transmission circuit is the input ground end that is connected via wires to sound signal by signal emission mouth, is connected an inductance L 1 between the power supply ground of the input ground end of sound signal and this circuit.

Above-mentioned vehicle-mounted frequency modulation playing device is characterized in that: the input power supply of power circuit is taken from the Cigarette lighter 12V power supply of automobile.

Above-mentioned vehicle-mounted frequency modulation playing device is characterized in that: the input power supply of power circuit outputs to the input end of voltage-stabilizing device at first through the filtering of LC filter circuit, and the out-put supply of voltage-stabilizing device is a working power.

The utlity model has following advantage: multiple players such as MD, MP3 can be play, increased the selection of playing source of sound in original auto audio equipment.

Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.

Description of drawings

Fig. 1 is a block scheme of the present utility model;

Fig. 2 is the block scheme of FM radio-frequency modulator;

Fig. 3 is FM radio-frequency modulator schematic circuit diagram;

The specific embodiment

As Fig. 1, Fig. 2, shown in Figure 3, a kind of vehicle-mounted frequency modulation playing device, comprise the audio-frequence player device 1 that produces sound source signal, vehicle-mounted FM radio receiver 3, loud speaker 4, it is characterized in that: also have a FM radio-frequency modulator 2, FM radio-frequency modulator 2 is made up of sound signal input circuit 5, Audio Signal Processing and FM modulation circuit 6, radio frequency amplification and transmission circuit 7, power circuit 8, is electrically connected between them; Because the FM signal is a metric wave, its emitting antenna will reach more than the 20cm, but the space is narrow and small in automobile, be unfavorable for conventional antennas such as device telescopic antenna, influence attractive in appearance again with the flexible cord antenna, if antenna too short (being lower than 10cm) can cause launching effect bad, be subject to situations such as interference, the solution of this circuit is such, radio frequency amplifies and the signal output antenna of transmission circuit 7 is the input ground ends 11 that are connected to sound signal by signal emission mouth 9 through lead 10, between the power supply ground 12 of the input ground end 11 of sound signal and this circuit, be connected an inductance L 1, for the high-frequency signal (88-89MHZ) that will launch, the induction reactance of L1 very big (greater than 100K Ω), be equivalent to open circuit, signal emission mouth 9 input ground end 11 that is connected to sound signal through lead 10 has just formed the antenna of this projector so, since sound signal input line will be more than 20cm length, be equivalent to this emitter antenna so and reach requirement above 20cm, (20 ~ 20KHz) frequencies are low for audio input signal, L1 is considered as short circuit, thereby for sound signal, audio frequency input ground links to each other with this circuit ground, incoming signal and output signal can not interfere with each other like this, have solved the problem of emitting antenna again; The input power supply of power circuit 8 is taken from the Cigarette lighter 12V power supply of automobile, with generally from the automotive engine the power taking source different, when having avoided car engine, the high frequency voltage that automobile current generator sends is burnt power unit, here the input power supply of power circuit 8 is at first through 13 filtering of LC filter circuit, output to the input end of voltage-stabilizing device 14 again, the out-put supply of voltage-stabilizing device 14 is a working power, LC filtering here is made up of big sensibility reciprocal inductance L 4 and capacitor C 29, and voltage-stabilizing device 14 adopts the three-terminal voltage-stabilizing pipe.The utility model is to utilize clear stereo FM frequency modulation module that the sound signal that will import is carried out frequency modulation, the frequency range in local FM broadcast station is avoided in selection, utilize existing FM radio receiver reception reduction on the vehicle audio then, promptly finished input to this sound signal, because emission is all carried out in car with reception, thereby the emissive power of modulator is very little can meet the demands, avoid the relevant frequency control standard of country, the distortion of sort signal conversion has guaranteed the requirement of signal low distortion conversion in 0.3% in addition.Be further described below in conjunction with present embodiment, the external audio frequency signal is imported by K4, after decay, be input to the 22nd pin and the 1st pin of IC1, IC1 is a processing stereo signals and the integrated package that is modulated into the FM signal, the 5th pin is a composite stereo acoustic conductance signal output frequently, pilot signal is through C12, JR1, C13, R9, R10 is transported on the capister D1, thereby influence is by L2, the capacitance of the LC oscillation circuit that C19 and D1 produce, produce frequency deviation, thereby finish frequency modulation, and IC1 the 9th pin is the vibration input, the 11st pin is a frequency modulated output, in order to stablize the frequency of frequency modulation operation point, the built-in phaselocked loop of IC1, when output frequency difference predeterminated frequency, the voltage of the 7th pin output changes, through R5, T1, R7, R8, R10 is added to the last output frequency of correcting of D1 and reaches preset requirement, the 15th of IC1,16,17 pin form frequency and select, this circuit provides 3 frequencies, and high-frequency signal is done the radio frequency amplification after the antenna emission by the 11st pin output of IC1 through T2.Vehicle audio has been mixed the FM radio-frequency modulator, make multiple players such as MD, MP3 in original auto audio equipment, to play, increased the selection of playing source of sound, and by particular design to antenna, the appearance effects of having avoided antenna to bring, by special design, improved reliability, the safety of power supply to power supply.

Claims

1, a kind of vehicle-mounted frequency modulation playing device, comprise the audio-frequence player device (1), vehicle-mounted FM radio receiver (3), the loud speaker (4) that produce sound source signal, it is characterized in that: also have a FM radio-frequency modulator (2), FM radio-frequency modulator (2) is made up of sound signal input circuit (5), Audio Signal Processing and FM modulation circuit (6), radio frequency amplification and transmission circuit (7), power circuit (8), is electrically connected between them.

2, vehicle-mounted frequency modulation playing device according to claim 1, it is characterized in that: radio frequency amplifies and the signal output antenna of transmission circuit (7) is to be connected to the input ground end (11) of sound signal by signal emission mouth (9) through lead (10), is connected an inductance L 1 between the power supply ground (12) of the input ground end (11) of sound signal and this circuit.

3, vehicle-mounted frequency modulation playing device according to claim 1 is characterized in that: the input power supply of power circuit (8) is taken from the Cigarette lighter 12V power supply of automobile.

4, vehicle-mounted frequency modulation playing device according to claim 1, it is characterized in that: the input power supply of power circuit (8) is at first through LC filter circuit (13) filtering, output to the input end of voltage-stabilizing device (14) again, the out-put supply of voltage-stabilizing device (14) is a working power.