CN2461208Y

CN2461208Y - Subminiature electronic tune FM high-frequency head for vehicle frequency-modulation receiver

Info

Publication number: CN2461208Y
Application number: CN 00268065
Authority: CN
Inventors: 柳成根
Original assignee: HUANGPU TAIFENG ELECTRONIC FACTORY BAOAN DISTRICT SHENZHEN CITY
Current assignee: HUANGPU TAIFENG ELECTRONIC FACTORY BAOAN DISTRICT SHENZHEN CITY
Priority date: 2000-12-22
Filing date: 2000-12-22
Publication date: 2001-11-21
Anticipated expiration: 2010-12-22

Abstract

The utility model relates to a subminiature electronic tuning FM high-frequency head for a vehicle mounted frequency-modulation receiver, which comprises an input loop, a high frequency amplifier circuit, an AGC circuit, a frequency mixing loop, a selection loop, a local oscillation circuit and a shielding outer housing. The utility model is characterized in that the high frequency amplifier part uses a double grid field effect transistor. The input loop, the selection loop and the local oscillation circuit respectively use a variable capacitance triode. The utility model is also provided with a local oscillation output circuit, and the shielding outer housing is a double light tin shielding outer housing. A connecting inserter is directly arranged on a circuit board. The utility model uses lamellar components and direct insertion type connecting components, and has compact structure and ideal wire layout. The direct insertion type installation reduces the covering surface with a main board, and the utility model can effectively decrease the distributed capacitance of a high frequency head and the main board. The performance indexes of the receiving sensitivity, the anti-interference performance, the selectivity, etc. are obviously improved than the performance indexes of the existing product.

Description

The vehicle-mounted FM receiver tuning FM tuner of Subminiature electronic

The utility model relates to auto radio, particularly a kind of vehicle-mounted FM receiver tuning FM tuner of Subminiature electronic.

Horizontal or the sitting type structure of the general employing of existing autoadio FM tuner takies auto radio mainboard area and is respectively 41 * 23mm ², 41 * 11mm ²It is big that this structure FM tuner takies auto radio motherboard area, very big to the property the applied flexibly influence of the inner space of auto radio, can better rationally not utilize the space, unfavorable to the reasonable line arrangement of mainboard.This structure is to distributed capacitance, external interference, and the phase mutual interference of high-frequency current can't be eliminated.Cause its receiving sensitivity, interference free performance and selectivity can't realize optimum Working.

The purpose of this utility model is to overcome the above-mentioned deficiency of prior art, a kind of vehicle-mounted FM receiver tuning FM tuner of Subminiature electronic is provided, it adopts direct insertion, and volume is little, and receiving sensitivity, interference free performance and selectivity etc. obviously improve than existing product.

This vehicle-mounted FM receiver tuning FM tuner of Subminiature electronic, comprise: the antenna input circuit, high-frequency amplifier circuit, the AGC control circuit, mixing return circuit, be connected in the selection loop between high-frequency amplifier circuit and the mixing return circuit,, it is characterized in that with mixing return circuit and local-oscillator circuit and screening can that the input of selecting the loop is connected:

Described high-frequency amplifier circuit adopts the field effect transistor high-frequency amplifier;

Antenna input circuit, selection loop and local-oscillator circuit adopt a transfiguration triode to constitute respectively; Also be provided with a local oscillation output loop, oscillation signals according is exported through the local oscillation output circuit, be used to the auto radio microprocessor that oscillation signals according is provided, after described microprocessor sampling, produce AGC voltage and tuning selection voltage VT that high-frequency amplifier circuit needs, the gain of AGC voltage control High Amplifier Circuit field effect transistor FET1, tuning selection voltage are used for the control antenna input circuit, select the varying capacity of the transfiguration triode of loop and local-oscillator circuit.

Described screening can is two light tinplate screening cans, and it connects one side that plug-in unit directly is installed on circuit board.

This direct insertion (vertical) electronic tuning FM tuner, screening can adopt the two light tinplate moulding of 0.5t, connect plug-in unit and adopt the punch forming of 0.6t brass sheet.Compare than the common tinplate material that traditional FM tuner is used, improved defence and oxidation resistant ability greatly high frequency radiation.

This fit compact conformation, wiring is desirable, the assembling advantages of simple, the pin function standard, owing to reduced coverage rate with the auto radio motherboard, can effectively reduce the distributed capacitance of tuner and auto radio mainboard, make the receiving sensitivity of tuner in automobile radio reception, interference free performance and selectivity are operated in optimum state.This structure also makes auto radio Developmental Engineer property applied flexibly to the inner space of auto radio in development and Design have very great help.This structure is that the inner space that the selected tuner of auto radio requirement requires auto radio is taken and will lack, demand sensitivity, and the best of the contradiction that selectivity and antijamming capability are strong is again selected for use.

The utility model high frequency head height is put part and is adopted dual gate FET, band AGC function, working stability, highly sensitive receiving unit adopt three groups of independently superheterodyne reception modes of forming of transfiguration triode and peripheral cell, improve wireless selectivity and antijamming capability comprehensively.

Fig. 1 is its functional-block diagram;

Fig. 2 is the embodiment circuit diagram;

Fig. 3 is the embodiment structural representation.

As shown in Figure 1, this FM tuner is by input circuit 1, high-frequency amplifier circuit 2, and AGC control circuit 3 is selected loop 4, local oscillation loop 5, mixing output loop 6 and local oscillation output circuit 7 are formed.Oscillation signals according is through 7 outputs of this vibration output circuit, be used to the auto radio microprocessor that oscillation signals according is provided, after described microprocessor sampling, produce AGC voltage and tuning selection voltage VT that the FM tuner needs, the 2. gain of field effect transistor FET1 of AGC voltage control High Amplifier Circuit, tuning selection voltage are used for the control antenna input circuit, select the varying capacity of the transfiguration triode of loop and this vibration circuit.

Signal flow is that the radio reception signal that is coupled into from C1 is through inductance coil L1, transfiguration triode D1 screens the back and is amplified by the paramount pipe FET1 of putting of C4 coupling, signal after the amplification exports inductance coil L2 to via R5, again by inductance coil L2, L3 is coupled to and selects the loop, select the loop by inductance coil L3, transfiguration triode D2 and select the oscillation signals according mixing of the high 10.7MHz of signal from the ratio that C8 provides, the signal after the mixing amplifies the back through triode TR1 and is selected to export by intermediate frequency transformer.

In embodiment circuit diagram 2, the antenna input circuit is by capacitor C 1～C4, inductance coil L1, and resistance R 2, transfiguration triode D1 forms.Inductance coil L1 is in parallel with transfiguration triode D1, and capacitor C 1, C2 connect the positive terminal of transfiguration triode D1, and capacitor C 1 other end connects the ANT pin of jointing; Capacitor C 3, C4, resistance R 2 connects another positive terminal of transfiguration triode D1; The middle negative pole series resistance R1 of transfiguration triode D1 connects tuning voltage end VT.

High-frequency amplifier circuit adopts the field effect transistor high-frequency amplifier, described field effect transistor high-frequency amplifier is made up of dual gate FET FET1, resistance R 3～R5 and inductance coil L2, resistance R 3, R4 connect the grid G 1 of field effect transistor FET1, FET1 grid G 2 pin connect AGC voltage, the drain D of field effect transistor FET1 links to each other with resistance R 5, the other end of resistance R 5 links to each other with resistance R 4, inductance coil L2, and field effect transistor FET1 source S terminal ground connection connects input circuit by capacitor C 4.

Agc circuit 3 is made up of the resistance R 8 of dual gate FET FET1 grid G 2 terminals, connection and described grid G 2 terminals and capacitor C 10, C12, and resistance R 8 other ends are the AGC end of connector in succession.

Select loop 4 by inductance coil L3, L4, capacitor C 5～C7, and transfiguration triode D2 forms.Enter the selection loop by inductance coil L3 from high-frequency amplifier circuit inductance coil L2 coupled signal, be coupled to mixing triode TR1 by capacitor C 6 again.Inductance coil L3, capacitor C 5, capacitor C 6 all link to each other with transfiguration triode D2 one positive terminal, another positive terminal ground connection of D2, and the middle negative terminal series resistance R6 of D2 is connected to the AGC end that connects plug-in unit, and capacitor C 7 series inductance coils connect capacitor C 6 again.

Local-oscillator circuit 5 is made up of inductance coil L5, transfiguration triode D3, capacitor C 18～C21, resistance R 13～R15 and triode TR2.Oscillator signal one routing capacitance C8 connects mixing and selects the loop, and a routing capacitance C16 connects the local oscillation output loop.Transfiguration triode D3 one positive terminal links to each other with the base stage b of triode TR2 through C19, and TR2 collector electrode c connects positive source through resistance R 13, and the TR2 emitter e is through resistance R 15 earth connections.Capacitor C 20 connects between the base stage b and emitter e of triode TR2.Another positive terminal ground connection of transfiguration triode D3, the middle negative terminal connecting resistance R12 of D3 is connected to the AGC end that connects plug-in unit.C18 is in parallel with D3, and C17 is connected between D3 negative terminal and the ground.

Mixing output loop 6 is by resistance R 7, capacitor C 8, C9, and triode TR1, and intermediate frequency transformer T1 forms.Capacitor C 8, C9, resistance R 7 all links to each other with triode TR3 base stage b, and TR3 collector electrode c connects the elementary s terminal of intermediate frequency transformer T1, the d terminal positive source VCC that intermediate frequency transformer T1 is elementary, the emitter e ground connection of TR3.The secondary s terminal of intermediate frequency transformer T1 connects the IF end of plug-in unit, and this pin is connected on the intermediate frequency input interface of auto radio FM, the secondary d terminal earth connection of intermediate frequency transformer T1.

Local oscillation output circuit 7 is by resistance R 10, R11, and capacitor C 15, C16 reach triode TR3 and form.Triode TR3 base stage is connected on the local oscillation loop through capacitor C 16, and the TR3 collector electrode is connected to the local oscillation signal output OSC end that tuner connects plug-in unit through capacitor C 15.The collector electrode of triode TR3 meets load resistance R10, and the base stage of triode TR3 meets base resistance R11, the emitter e ground connection of triode TR3.

After the tuning voltage of auto radio microprocessor output is introduced from the connection plug-in unit Vt end of tuner, deliver to the public negative pole of transfiguration triode D1, D2, D3 respectively through resistance R 1, R6, R12, to adjust the capacity of transfiguration triode.

Each several part shown in Fig. 3 example structure schematic diagram is: screening can 31, intermediate frequency transformer 32,1.2t wiring board 33, electronic component 34, flat shape electronic component 35,

fixing pin

36 and 38, attachment plug 37, and

spring coil

39,40 and 41 etc.Attachment plug 37 is counted from the structural representation left side and is respectively 1., 2., and 3., 4., 5., 6. pin.Each pin function is respectively 1. antenna input ANT, 2. automatic gain control AGC, 3. power supply supply VCC, 4. tuning voltage VT, 5. intermediate frequency output IF, 6. local oscillation output OSC.

Attachment plug 37 lead terminals adopt 0.6t brass sheet roll forming.Screening can 31 adopts the two light tinplate moulding of 0.5t, chooses this two kinds of material pin terminals and screening can, has improved the ability that prevents high frequency radiation and non-oxidizability of tuner greatly.Flat shape electronic component 35 is mounted on the wiring board of 1.2t; Intermediate frequency transformer 32,

spring coil

39,40,41, electronic component 34 are inserted on the wiring board of 1.2t, attachment plug is welded on the exit of 1.2t wiring board 33, whole wiring board is fixed on the fixedly pad of screening can, shown connection plug-in unit 37 is 6 line attachment plugs, and it directly is welded on circuit board.

Whole tuner is inserted on the mainboard of auto radio by the vertical direction of diagram, the fixedly

36,38 of the larger areas of copper platinum ground wire welding tuner on the auto radio mainboard.1. the antenna input of 6 line attachment plugs of tuner connects the antenna input of auto radio, 2. AGC control connect on the AGC terminal of auto radio microprocessor, 3. power supply VCC connects on the 8V power supply terminal of auto radio, 4. tuning voltage VT connects on the VT terminal on the auto radio microprocessor, 5. intermediate-freuqncy signal output IF connects auto radio FM signal input end of intermediate frequency, and 6. local oscillation signal output OSC connects on the OSC terminal of auto radio microprocessor FM.Since the connection plug-in unit of tuner can corresponding auto radio standard interface, adopt the straight cutting fit, so the entire mechanism assembling is simple, interferes with each other and lack stable performance.Fit adopts direct insertion (vertical) structure, and taking auto radio mainboard area is 19.5 * 7.7mm ², only be in half of traditional F M tuner.

The direct insertion microminiature FM tuner of the utility model has realized dwindling the requirement that takies the auto radio inner space.Take auto radio mainboard area by 41 original * 23mm ²With 41 * 11mm ²Dwindle the 19.5 * 7.7mm of this product ²Owing to adopted direct insertion mounting process, make that auto radio internal structure when the assembling tuner is compact more, it is more reasonable to connect up, and assembly technology is simpler, saves production cost to reach three fens more than one.Especially adopted direct insertion installation, taken auto radio mainboard area than original minimizing three minutes more than two, making is having bigger help to auto radio property applied flexibly to the space in development and Design.The more important thing is and adopt direct insertion installation to reduce the contact-making surface of tuner with the auto radio mainboard, reduced distributed capacitance and the high-frequency current undesirable element of mutual interference mutually between them, make tuner in auto radio the inside in sensitivity, selectivity and antijamming capability aspect are operated in optimum state.

The direct insertion FM tuner of the utility model can be applicable in all auto radios that possess electronics channel selection function, and simple installation, and debugging can be saved auto radio mainboard area easily greatly.The inner space property applied flexibly to auto radio is very helpful, and plays an important role to reducing automobile radio reception production cost.

Claims

1, a kind of vehicle-mounted FM receiver direct insertion electronic tuning FM of microminiature tuner, comprise: the antenna input circuit, high-frequency amplifier circuit, the AGC control circuit, mixing return circuit, be connected in the selection loop between high-frequency amplifier circuit and the mixing return circuit,, it is characterized in that with mixing return circuit and local-oscillator circuit and screening can that the input of selecting the loop is connected:

Described high-frequency amplifier circuit adopts the field effect transistor high-frequency amplifier; Antenna input circuit, selection loop and local-oscillator circuit contain a transfiguration triode respectively; Also be provided with a local oscillation output circuit, be used to the auto radio microprocessor that oscillation signals according is provided;

2, according to the described vehicle-mounted FM receiver of the claim 1 direct insertion electronic tuning FM of microminiature tuner, it is characterized in that: described field effect transistor high-frequency amplifier is made up of dual gate FET FET1, resistance R 3～R5 and inductance coil L2, resistance R 3, R4 connect the grid G 1 of dual gate FET FET1, grid G 2 pin of dual gate FET FET1 connect AGC voltage, the drain D of dual gate FET FET1 links to each other with resistance R 5, the other end of resistance R 5 links to each other dual gate FET FET1 source S terminal ground connection with resistance R 4, inductance coil L2.

3, according to the described vehicle-mounted FM receiver of the claim 1 direct insertion electronic tuning FM of microminiature tuner, it is characterized in that: described local oscillation output circuit is by triode TR3, the base resistance R10 of triode TR3, the load resistance R11 of triode TR3, and capacitor C 15, C16 are formed, triode TR3 base stage is connected to local-oscillator circuit through capacitor C 16, and collector electrode is connected to the OSC pin that connects plug-in unit through capacitor C 15.

4, according to the described vehicle-mounted FM receiver of the claim 1 direct insertion electronic tuning FM of microminiature tuner, it is characterized in that: described connection plug-in unit is 6 line attachment plugs, and the fit of employing straight cutting is installed on one side of circuit board.

5, according to the described vehicle-mounted FM receiver of the claim 1 direct insertion electronic tuning FM of microminiature tuner, it is characterized in that: the lead terminal of described connection plug-in unit is the brass sheet roll forming.