CN2243148Y - Frequency channel selecting device for television - Google Patents

Abstract

The utility model provides a channel convertor for televisions, which specially provides television video signals for projectors. The utility model is characterized in that the utility model comprises a casing and a television channel converting circuit board which is arranged in the casing and composed of a tuner, a CPU microprocessor unit, an intermediate-frequency amplifier, a video buffer, a power circuit, etc., wherein the television channel converting circuit is electrically connected with a remote-control receive line, an indicator and a button circuit board and with a power input terminal port, a television signal input terminal port and output terminal ports for audio and video signals on a rear panel of the casing respectively.

Description

A kind of television channel transducer

The utility model relates to TV signal receiver, particularly a kind of television channel transducer.

Mainly comprise projector and screen in the existing home theater projection system.Because projector can only receiving video signals, can not received RF signal, therefore the multichannel television set that has audio frequency, video output be must be equipped with when using projector's projection TV programme or Video Adapter and sound blaster mixed by computer, but above-mentioned corollary equipment is complex structure not only, and cost is high too.Though another kind of cable television channels transducer simple structure, cheap, it exports radiofrequency signal, can only with the supporting use of television set.Therefore up to the present, also there are not a kind of output video respectively, audio signal, the special television channel transducer that the television program video signal is provided for projector.

The purpose of this utility model is exactly that a kind of simple structure, the special television channel transducer that the television program video signal is provided for projector will be provided.

Task of the present utility model is finished as follows.

A kind of television channel transducer, has housing, be located at remote control receiving lines plate and indicator light on the described housing front panel, the button wiring board, be located at power input mouth and tv signal input mouth on the described housing rear board, be provided with in the described housing and comprise tuner, the CPU microprocessor, intermediate frequency amplifier, power circuit is at interior television channel conversion line plate, described television channel conversion line respectively with remote control receiving lines plate and indicator light, the button wiring board, power input mouth and tv signal input mouth are electrically connected, the audio signal output end that its characteristics are described television channel conversion line internal intermediate frequency amplifier is by being electrically connected with audio output port on the rear board with the resistance of its coupling and electric capacity, and the VT of described intermediate frequency amplifier is electrically connected with VT mouth on the described rear board by video buffer.

The intermediate frequency amplifier of the utility model television channel transducer can adopt the TDA4501 integrated circuit, and its audio output the 12nd pin is by resistance R T ₁₄-0.25-2.4K-II, capacitor C L ₁₁-0.1 μ F-50V-II coupling audio output port back and on the housing rear board is electrically connected; Its VT the 17th pin passes through by inductance 3751S, resistance 680 Ω, trapper * 6.5M, triode A1015, resistance R T ₁₄-0.25-1K-I, resistance R T ₁₄-0.25-390 Ω-I, resistance R T ₁₄-1K, resistance R T ₁₄-0.25-82 Ω-I and capacitor C D ₁₁The video buffer that-470 μ F-16V-II form is electrically connected with the VT mouth on the housing rear board.

The intermediate frequency amplifier of the utility model television channel transducer can adopt the TA2680A integrated circuit, and its audio signal output end the 3rd pin is by resistance R T ₁₄-0.25-2.4K-I, capacitor C D ₁₁-10 μ-16V-II coupling audio output port back and on the rear board is electrically connected, and its VT the 15th pin passes through by inductance 5.6 μ H, resistance 330 Ω, trapper * 6.5M, triode 2SC1815, resistance R T ₁₄-0.25-220 Ω-I, resistance R T ₁₄-0.25-82 Ω-I, resistance R T ₁₄-0.25-470 Ω-I and capacitor C D ₁₁The video buffer that-470 μ F-16V-II form is electrically connected with the VT mouth on the rear board.

What the utility model television channel transducer internal intermediate frequency amplifier audio signal output end was exported is crossing signal, have only by ability output audio signal after the capacitive coupling, use for the sound system with projector coupling, series resistance can weaken strong audio signal.Behind the video buffer circuit of the vision signal of intermediate frequency amplifier VT output via inductance, trapper, triode and some resistance composition, both can the elimination audio signal to the interference of vision signal, the peak value that can prevent the vision signal output voltage again is too high, avoids producing negative-appearing image (television image that is projector's projection becomes negative image) because of the vision signal obstruction.Thereby guarantee that the utility model television channel transducer can provide normal television video frequency signal to projector, makes the projection function show out whole standard television broadcasting channels and cable TV additional channel.

Compared to the prior art, television channel transducer of the present utility model is except can be to projector provides the television program video signal, and the advantage that it is simple in structure, cheap in addition, the price of a television channel transducer are only between 300-400 unit.

Below with reference to the embodiment accompanying drawing structure of the present utility model is described in further detail.

Fig. 1 is the D structure schematic diagram of the utility model television channel transducer.

Fig. 2 is the operation principle block diagram of the utility model television channel transducer.

Fig. 3 is the first of the utility model television channel change-over circuit embodiment 1.

Fig. 4 is the second portion of the utility model television channel change-over circuit embodiment 1.

Fig. 5 is the third part of the utility model television channel change-over circuit embodiment 1.

Fig. 6 be the utility model television channel change-over circuit embodiment 2 from intermediate frequency amplifier the line map to audio output port, video-out port.

Consult Fig. 1, the utility model television channel transducer comprises housing 1, be located at remote control receiving lines plate on the housing front panel and indicator light 2, button wiring board 3, be located at power input mouth 4, tv signal input mouth 5, Audio output port 7 and VT mouth 8 on the described housing rear board, be provided with television channel conversion line plate 6 in the described housing.Consult Fig. 2, TV signal enters tuner through antenna input port, and the TV signal of tuner output is divided two-way, and route CPU microprocessor control tuner is in BL (low-frequency range), BH (high band) or UHF (VHF band) work.Another road TV signal is after intermediate frequency amplifier amplifies, and the audio signal of intermediate frequency amplifier output is exported by audio output port after resistance-capacitance coupling; The vision signal of intermediate frequency amplifier output is exported by video-out port behind video buffer.Consult Fig. 3-Fig. 5, Fig. 3 is connected with Fig. 41 ', 2 ', 3 ', 4 ', 5 ', 6 ', 7 ' some place in the drawings, Fig. 4 is connected with Fig. 58 ', 9 ', 10 ', 11 ', 12 ', 13 ', 14 ', 15 ', 16 ', 17 ', 18 ', 19 ' some place in the drawings, Fig. 3, Fig. 4, Fig. 5 form the television channel change-over circuit of embodiment 1 together, TV signal enters tuner IF through antenna input port, the signal of tuner output divides two-way, leads up to microprocessor IC ₃(CTV222S) control frequency range converter ic IC ₅(LA7910) make tuner IF in BL, BH or the work of VHF section, described frequency range converter ic IC ₅Form the TV signal commutation circuit with tuner.Another road TV signal of tuner output IF carries out earlier putting in pre-, then through SAW (Surface Acoustic Wave) filter SAWF in put integrated circuit (IC) ₁(TDA4501) the 8th, the 9th pin, signal is after intermediate frequency amplifier is handled, by IC ₁The 12nd pin output hand over audio signal more, described signal is through capacitor C ₂₀(0.1 μ) coupling back is by audio signal output end 7 outputs.By intermediate frequency amplifier IC ₁The television video frequency signal of the 17th pin output is through inductance T ₄(3751S), resistance R ₃₄(680 Ω), filter CF ₂Behind the interference component in (* 6.5) filtering vision signal by triode Q ₃(A1015) anode input, triode Q ₃Grounded collector, base stage and load resistance R ₃₆(1K) be electrically connected, make triode Q ₃Be in the emitter following state, resistance R ₃₇(390 Ω), R ₃₈(1K) as bleeder circuit, foregoing circuit plays the video buffer effect, can prevent that the too high vision signal that makes of peak value of vision signal output voltage from stopping up and the generation negative-appearing image resistance R ₁₀₀(82 Ω), capacitor C ₁₀₀(470 μ F) as signal coupling usefulness, television video frequency signal is by VT 8 outputs.The dashed rectangle of Fig. 3 top is remote control receiving lines plate and the indicator light of being located on the housing front panel 2, the S of Fig. 3 lower left ₁-S ₃Be the button wiring board 3 on the housing front panel, the antenna input of Fig. 3 upper left side tuner IF is electrically connected with tv signal input mouth 5 on the housing rear board, and the power circuit in the frame of broken lines of Fig. 5 top is electrically connected with the power input mouth 4 on the housing rear board.Consult Fig. 6, Fig. 6 only shows the later Voice ﹠ Video output circuit of embodiment 2 intermediate frequency amplifiers (difference technical characterictic part of the present utility model).The intermediate frequency amplifier of embodiment 2 adopts the TA7680AP integrated circuit, and its audio signal output end the 3rd pin is by resistance R T ₁₄-0.25-2.4K-I, capacitor C D ₁₁-10 μ-16V-II coupling back is by audio signal output end 7 outputs.By intermediate frequency amplifier IC ₁The interference component of television video frequency signal in inductance 5.6 μ H, resistance 330 Ω, trapper * 6.5M filtering vision signal of TA7680AP the 15th pin output, be electrically connected triode 2SC1815, and make described triode be in the emitter following state, resistance 82 Ω, 470 Ω and electric capacity 470 μ F play video buffer and coupling, can guarantee the normal vision signal of video output terminals 8 outputs.Part before the embodiment 2 intermediate frequency amplifier TA7680AP is known by present technique field those of ordinary skill, so repeat no more in specification and accompanying drawing thereof.

When the utility model television channel transducer uses, power input mouth 4 on the housing rear board is connected with power supply, tv signal input mouth 5 is connected with television antenna, and Audio output port 7 is connected with sound equipment in the household audio and video system, and VT mouth 8 is connected with projector.The operation of television channel transducer both can utilize hand-held remote controller, also can use button.When the utility model television channel transducer and projector's coupling are used, can make projector show the program of whole standard television broadcasting channels and cable TV additional channel, and can in projection screen, show control content.

Claims (3)

1, a kind of television channel transducer, has housing (1), be located at remote control receiving lines plate and indicator light (2) on the described housing front panel, button wiring board (3), be located at the power input mouth (4) on the described housing rear board, tv signal input mouth (5), be provided with in the described housing and comprise tuner, the CPU microprocessor, intermediate frequency amplifier, power circuit is at interior television channel conversion line plate (6), described television channel conversion line respectively with remote control receiving lines plate and indicator light, the button wiring board, power input mouth and tv signal input mouth are electrically connected, the audio signal output end that it is characterized in that described television channel conversion line internal intermediate frequency amplifier is by being electrically connected with audio output port (7) on the housing rear board with the resistance of its coupling and electric capacity, and the VT of described intermediate frequency amplifier is electrically connected with VT mouth (8) on the described housing rear board by video buffer.

2, television channel transducer according to claim 1 is characterized in that when intermediate frequency amplifier adopted the TDA4501 integrated circuit, its audio signal output end the 12nd pin was by resistance R T ₁₄-0.25-2.4K-II, capacitor C L ₁₁-0.1 μ F-50V-II coupling audio output port (7) back and on the rear board is electrically connected; Its VT the 17th pin passes through by inductance 3751S, resistance 680 Ω, trapper * 6.5M, triode A1015, resistance R T ₁₄-0.25-1K-I, resistance R T ₁₄-0.25-390 Ω-I, resistance R T ₁₄-1K, resistance R T ₁₄-0.25-82 Ω-I and capacitor C D ₁₁The video buffer that-470 μ F-16V-II form is electrically connected with the VT mouth (8) on the rear board.

3, television channel transducer according to claim 1 is characterized in that when intermediate frequency amplifier adopted the TA7680AP integrated circuit, its audio signal output end the 3rd pin was by resistance R T ₁₄-0.25-2.4K-I, capacitor C D ₁₁-10 μ-16V-II coupling audio output port (7) back and on the housing rear board is electrically connected, and its VT the 15th pin passes through by inductance 5.6 μ H, resistance 330 Ω, trapper * 6.5M, triode 2SC1815, resistance R T ₁₄-0.25-220 Ω-I, resistance R T ₁₄-0.25-82 Ω-I, resistance R T ₁₄-0.25-470 Ω-I and capacitor C D ₁₁The video buffer that-470 μ F-16V-II form is electrically connected with the VT mouth (8) on the housing rear board.

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