CN2177314Y

CN2177314Y - Satillite TV repeater

Info

Publication number: CN2177314Y
Application number: CN 93245398
Authority: CN
Inventors: 张毅
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-11-19
Filing date: 1993-11-19
Publication date: 1994-09-14
Anticipated expiration: 2003-11-19

Abstract

The utility model relates to a converting device for TV signals, which comprises a satellite television receiving circuit, a radio frequency modulation circuit and a radio-frequency power amplifying circuit. The receiving circuit is composed of an integrated tuner, an AFC and an audio video processing circuit. The radio frequency modulation circuit comprises a radio frequency modulation integrated circuit, a sound frequency-selection network, a signal mixing network, a vestigial sideband filter and an amplifier. Since the method of once frequency conversion and a set of a switch type stabilized voltage supply, a CPU control system and a remote controller in the prior art are simplified. Therefore, the debugging and maintenance of the circuits and devices are obviously simplified, the reliability and the applicability to the power feeding are improved and the cost is reduced.

Description

Satillite TV repeater

The utility model relates to a kind of conversion equipment of TV signal.

Existing satellite television relay devices is made up of several complete equipments such as satellite television receiver, intermediate frequency modulator and television transmitter of complexity.The C of Toshiba's (day) for example ₄The type satellite television receiver by integrated tuner, cpu controller, remote controller or/and control button, video processing circuits and audio frequency processing circuit.The satellite TV signal that is received by satellite tv antenna is delivered to the integrated tuner of satellite television receiver, under the cpu controller control in receiver, according to remote controller or panel control button operation carry out channel selection and sound accompaniment tuning.Be provided with image frequency discriminator, agc circuit, AFT circuit in the integrated tuner, the signal that satellite tv antenna can be sent here demodulates baseband signal, deliver to video processing circuits and audio frequency processing circuit respectively, postemphasis, processing output audio video (AV) signals such as the diffusion of deenergizing send intermediate frequency modulator.

The effect of intermediate frequency modulator (for example Chunan, Zhejiang Province radio factory produce DZSV type) be the AV signal with satellite television receiver output to be modulated into vision carrier frequency be 38MHz, sound carrier frequency is the medium standard frequency signal of 31.5MHz.

Television transmitter (for example DCH-3-III type of Chunan, Zhejiang Province radio factory production) comprises intermediate level circuit, agc circuit, frequency mixer, local oscillation circuit, excitation amplifying circuit and power amplifier etc.The medium standard frequency signal of intermediate frequency modulator output amplifies in the agc circuit effect, deliver to frequency mixer and local oscillation signal again and carry out mixing, for making emission signal frequency that enough stabilitys be arranged, local oscillation circuit is comparatively complicated, generally is provided with local oscillator level, amplifying stage, frequency multiplier circuit and filter.

The said equipment is for grapefruit satellite TV relay stations (transmitting power is less than 10W) such as vast rural area, mountain areas; need 3 complete equipments, the circuit complexity has circuit much unnecessary or that repeat to be provided with; debug difficulties often causes the not normal or device damage of work greatly because of mains ripple.

The purpose of this utility model aims to provide a kind of employing single-conversion formula, and circuit is oversimplified, and debugging is simple, and cost is lower, the grapefruit satellite television repeater that applicability is stronger.

The utility model comprises satellite television receiving circuit, rf modulation circuit, rf power amplifier circuit and power supply.The output of satellite television receiving circuit connects rf modulation circuit, and the output of rf modulation circuit connects rf power amplifier circuit.

The satellite television receiving circuit comprises integrated tuner, AFC circuit, audio frequency processing circuit, video processing circuits.The AFT signal output part of integrated tuner is connected with the AFC circuit; The baseband signal output of integrated tuner is connected with video processing circuits with audio frequency processing circuit respectively.Audio frequency processing circuit comprises emitter follower, sound channel frequency selection circuit, sound accompaniment frequency discrimination integrated circuit, de-emphasis network and amplifying circuit.The input of emitter follower is connected with the baseband signal output of integrated tuner, the output of emitter follower connects the sound channel frequency selection circuit, the output of sound channel frequency selection circuit connects sound accompaniment frequency discrimination integrated circuit, the output of sound accompaniment frequency discrimination integrated circuit connects de-emphasis network, and the output of de-emphasis network connects amplifying circuit.Video processing circuits comprises that emitter follower, de-emphasis network, video frequency-selective network, video amplifier circuit, clamp remove to spread circuit and final stage emitter follower.The input of emitter follower is connected with the baseband signal output of integrated tuner, the output of emitter follower connects de-emphasis network, the output of de-emphasis network connects the video frequency-selective network, the output of video frequency-selective network connects video amplifier circuit, the output of video amplifier circuit connects clamp and removes to spread circuit, and clamp removes to spread circuit and connects emitter follower.

Rf modulation circuit comprises AV signal rf modulations integrated circuit, sound accompaniment frequency-selective network, signal hybrid network, vestigial sideband filter, wide-band amplifier.The input of AV signal rf modulations integrated circuit connects the audio frequency processing circuit of satellite television receiving circuit and the output of video processing circuits respectively, the sound accompaniment composite signal output termination sound accompaniment frequency-selective network of AV signal rf modulations integrated circuit, the main carrier frequency signal output part of the output of sound accompaniment frequency-selective network and AV signal rf modulations integrated circuit connects the signal hybrid network, the output of signal hybrid network connects vestigial sideband filter, and the output of vestigial sideband filter connects wide-band amplifier.

Rf power amplifier circuit comprises pre-amplification circuit, excitation amplifying circuit and power amplification output circuit, connects successively.

The complete machine power supply can adopt the stabilized voltage power supply of common tandem type, also can adopt the switching regulator stabilized voltage power supply.

Compare with existing satellite television forwarding unit, the utility model has obviously been simplified circuit and debugging, has improved stability, has reduced cost.Existing satellite television forwarding unit adopts the double conversion working method, needs complicated local oscillation circuit and mixting circuit and well behaved filter; In addition, also need system control cpu and remote controller in the receiver, need 3 cover stabilized voltage power supplys, owing to adopt common series regulator usually, the shakiness of establishing the station regional power supply causes the operating voltage fluctuation big, influences the operate as normal of repeater station; Simultaneously, because forwarding unit is made up of several equipment, obviously increased the cost of building a station.

The utility model adopts the single-conversion working method, directly the output signal of satellite receiving circuit is modulated into the signal of the channel that will launch, has reduced intermediate frequency amplifier circuit, agc circuit, mixting circuit and the local oscillation circuit etc. of double conversion circuit; In addition, according to the practical needs of relay base, general steady job is at a certain channel, and the less operation of carrying out channel selection and transferring sound accompaniment so can simplify system control cpu and remote controller, is simplified circuit significantly, has improved reliability, has reduced cost; Simultaneously, the utility model can adopt a cover switching regulator stabilized voltage power supply, even the voltage of electrical network fluctuates in 140～270V scope, all can stablize the various D.C. regulated power supplies that provide repeater-transmitter required.

Fig. 1 is a functional-block diagram of the present utility model.

Fig. 2 is a satellite television receiving circuit schematic diagram of the present utility model.

Fig. 3 is a rf modulation circuit schematic diagram of the present utility model.

Fig. 4 is a rf power amplifier circuit schematic diagram of the present utility model.

Fig. 5 is a stabilized voltage power supply schematic diagram of the present utility model.

Below in conjunction with accompanying drawing the utility model is described further.

As shown in Figure 1, the utility model is by satellite television receiving circuit (1～4), rf modulation circuit (5), rf power amplifier circuit (6～8) and switching regulator stabilized voltage power supply (9).The satellite television receiving circuit comprises general integrated tuner (1), AFC circuit (2), audio frequency processing circuit (3) and video processing circuits (4).Integrated tuner (for example TSU2-E01P type) receives 950～1450MHz, first intermediate-freuqncy signal of being sent here by outdoor unit, at its 9th end output AFT signal (referring to Fig. 2), through 2R ₂₅, 2R ₂₆Deliver to by IC after the dividing potential drop ₁The 7th end on output one stable tuning voltage deliver to the 3rd end (V of integrated tuner _TEnd) on, plays the effect of tuning channel selection.Integrated tuner the 2nd end is to the outdoor unit feed end, diode 2D ₁Play unidirectional buffer action, prevent with other and connect the mutual short circuit of feed of satellite television receiver.What the 8th end was sent is the baseband signal of amplifying through demodulation, respectively by 2R ₁, 2C ₁And 2R ₃₂Be coupled to audio frequency processing circuit and video processing circuits.

2BG ₁Be the emitter follower isolation level, baseband signal is by 2C ₂～2C ₆, 2L ₁, 2L ₂And 2R ₅, 2R ₆The sound channel frequency selection circuit of forming is selected the satellite television audio signal of 5.5～7.5MHz, and the vision signal of filtering 0～5.5MHz prevents that it from disturbing sound accompaniment.Deliver to IC through filtered audio signal ₂(NE564) the 6th end, IC ₂Be sound accompaniment frequency discrimination integrated circuit, the external resonant capacitance of its 12nd, 13 end can determine its frequency discrimination operating frequency, on its branch road and variable capacitance diode 2D arranged ₃, 2D ₄, tuning voltage is by sound accompaniment trim-pot W ₂Provide.

Through IC ₂Audio signal behind the frequency discrimination is exported by the 14th end, through 2R ₁₄, 2R ₁₅, 2C ₁₈The de-emphasis network of forming will be removed by the preemphasized signal that signal sending end adds, reverts to the television audio signals that can Gong listen to, again through 2BG ₃, 2BG ₄The back is amplified by 2BG in the two poles of the earth ₅Radio-frequency (RF) device is isolated back output (AUDIO.OUT).

Another route emitter follower 2BG of the baseband signal of integrated tuner output ₆Isolate after by 2L ₃, 2C ₂₆, 2R ₃₅～2R ₃₈The de-emphasis network of forming, and by 2L ₄, 2L ₅, 2C ₂₇～2C ₂₉And 2R ₃₉0～6MHz video frequency-selective network of forming is delivered to IC after the High-frequency Interference of filtering audio signal ₃(NE592) video amplifier circuit of Zu Chenging is from IC ₃The vision signal of the 7th end output removes to spread circuit (by 2C through clamp ₃₂～2C ₃₄And 2D ₅, 2D ₆Form), the removal transmitting terminal is added in the triangular wave in the vision signal, at last by 2BG ₇, 2BG ₈The two-stage emitter follower is isolated amplification output (VIDEO.OUT).

Referring to Fig. 3, by the vision signal of satellite television receiving circuit output through 3W ₁, 3C ₁Be coupled to IC ₄(TA7673) on the 16th end, resonant tank 3L ₃, 3C ₁₄Be tuned on the sound carrier frequency of 6.5MHz, the channel that the resonant element on the 10th end (SAW, SAW (Surface Acoustic Wave) resonator) can be launched is as required selected for use, to produce the main carrier frequency of required transmitting channel.Main carrier frequency and sound carrier frequency signal are at IC ₄In through modulation, mixing, contain main carrier frequency one of the 2nd end output and add the composite signal that sound carrier frequency and main carrier frequency subtract sound carrier frequency.By 3C ₉～3C ₁₂, 3L ₁, 3L ₂The sound accompaniment frequency-selective network of forming is selected main carrier frequency and is added the sound carrier frequency signal, and by IC ₄The main carrier frequency signal of the 15th end output is at 3R ₃, 3R ₅, 3R ₉Mix in the hybrid network of forming, obtain the radio frequency output signal.

Audio signal is by by 3R ₈, 3C ₁₇, 3R ₇Be added to IC behind the preemphasis network of forming (improving the modulation Television Sound Quality) ₄The 6th end.3R ₁And 3R ₆Be IC ₄The load resistance of output signal.3W ₁, 3W ₂Be used to adjust the power of input signal.

3C ₁₈～3C ₂₆And 3L ₅～3L ₈Form the vestigial sideband filter that meets television signal standards, the output signal of vestigial sideband filter is through broadband high-gain amplifier IC ₅(OM2070) can in the VHF frequency range, the TV signal to 1～12 channel amplify more than the 28dB, again through 3BG ₁(MFR571) power amplification in reaches about 115dB signal.3C ₃₁, 3L ₁₁And 3C ₃₃Be 3BG ₁The output coupling circuit, 3R ₁₄～3R ₁₆Form π type attenuator, its effect is to carry out impedance matching better with the subordinate circuit.

Referring to Fig. 1 and Fig. 4, rf power amplifier circuit comprises two-stage small-signal preposition (in advance) amplifier (6), excitation amplifying circuit (7) and final stage power amplification output circuit (8).Rf modulated signal is earlier through 4BG ₁, 4BG ₂The two-stage small-signal amplifies, again by 4BG ₃The excitation amplifying circuit promotes 4BG ₄Final stage power amplifier.4R ₂₆～4R ₂₈Form 75 Ω matched transform devices.

The stabilized voltage power supply of this machine adopts the switching regulator stabilized voltage power supply, referring to Fig. 5.IC ₆The 4th, 8 ends standard source is provided, the 3rd end is the current detecting end, when just starting shooting, by 5R ₃To the 7th end power supply,, can start IC when voltage during greater than 16V ₁, IC ₁After the startup, in the adjustable square-wave signal of the 6th end output pulse width.B ₂Be switch transformer, its 3 groups of secondary windings are by 3 fast recovery diode rectifications, by 5L ₁～5L ₃And 5C ₁₂～5C ₁₉Form pi type filter, by 5R ₅, 5W ₁And 5R ₆IC is adjusted in the voltage ratio control that provides ₆Operating frequency.This power supply provides+24V ,+18V and+12V3 road stabilized voltage power supply.

Claims

1, a kind of satellite television repeater-transmitter comprises satellite television receiving circuit, modulation circuit, rf power amplifier circuit and stabilized voltage power supply, and satellite television receiving circuit, modulation circuit, rf power amplifier circuit connect successively, it is characterized in that

(1), the satellite television receiving circuit comprises integrated tuner, AFC circuit, audio frequency processing circuit, video processing circuits, the AFT signal output part of integrated tuner is connected with the AFC circuit, and the baseband signal output is connected with audio frequency, video processing circuits respectively; Audio frequency processing circuit comprises emitter follower, sound channel frequency selection circuit, sound accompaniment frequency discrimination integrated circuit, de-emphasis network and amplifying circuit, the input of emitter follower is connected with the baseband signal output of integrated tuner, the output of emitter follower connects the sound channel frequency selection circuit, the output of sound channel frequency selection circuit connects sound accompaniment frequency discrimination integrated circuit, the output of sound accompaniment frequency discrimination integrated circuit connects de-emphasis network, and the output of de-emphasis network connects amplifying circuit; Video processing circuits comprises that emitter follower, de-emphasis network, video frequency-selective network, video amplifier circuit, clamp remove to spread circuit and final stage emitter follower, and the baseband signal output of integrated tuner, emitter follower, de-emphasis network, video frequency-selective network, video amplifier circuit, clamp remove to spread circuit and be connected successively with the final stage emitter follower;

(2), modulation circuit is established rf modulation circuit, comprise AV signal rf modulations integrated circuit, the sound accompaniment frequency-selective network, the signal hybrid network, vestigial sideband filter and wide-band amplifier, the input of AV signal rf modulations integrated circuit connects the audio frequency of satellite television receiving circuit respectively, the output of video processing circuits, the sound accompaniment composite signal output termination sound accompaniment frequency-selective network of AV signal rf modulations integrated circuit, the main carrier frequency signal output part of the output of sound accompaniment frequency-selective network and AV signal rf modulations integrated circuit connects the signal hybrid network, the signal hybrid network, vestigial sideband filter is connected successively with wide-band amplifier again;

(3), rf power amplifier circuit comprises pre-amplification circuit, excitation amplifying circuit and power amplification output circuit, connection successively.

2, satellite television repeater-transmitter as claimed in claim 1 is characterized in that adopting the switching regulator stabilized voltage power supply.