CN107770412A - The generation device of scanning signal - Google Patents

Abstract

The invention discloses the generation device of scanning signal, including buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device, row separator, field split circuit, the buffer inputs composite video signal, the buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device are sequentially connected；The row separator is connected with sync separator, the field split circuit connection, and the field split circuit exports pulse, and the signal of the field split circuit output passes through outer blanking；Crystal oscillator is connected with voltage controlled oscillator, the 2nd APC circuits will also receive line flyback pulse.The present invention improves the stability of scanning system by buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device, row separator, field split circuit.

Description

The generation device of scanning signal

Technical field

The present invention relates to sweep generator, and in particular to the generation device of scanning signal.

Background technology

TV (Television, TV, Video) refers to the image frame and audio using electronic technology and equipment transmission activity Signal, i.e. television receiver, and important broadcast and video communication instrument, television set is earliest by Britain engineer John Lip river Lucky Baird is invented in nineteen twenty-five.The visual pattern of TV electronically transmission activity immediately.It is similar with film, TV profit Show the rest image of a frame frame gradual change with the persistence of vision effect of human eye, form visual live image.Television system is sent out It is order transmission after electric signal that each fine fraction of scenery is pressed brightness and chroma conversion by sending end.In receiving terminal by corresponding several What position shows brightness and the colourity of each fine fraction to reappear view picture original image.The progress of science and technology, is that TV is rapid One major reason of popularization.Various countries' TV signal scanning standard and channel broadband are incomplete same, are seeked advice from by international wireless electricity The suggestion of the committee (CCIR) is distinguished with the Latin alphabet.The scanning system stability of existing television set is weaker, and output signal is held It is also easy to produce snowflake.

The content of the invention

The technical problems to be solved by the invention are that the scanning system stability of existing television set is weaker, and output signal is easy Snowflake is produced, and it is an object of the present invention to provide the generation device of scanning signal, improves the stability of scanning system.

The present invention is achieved through the following technical solutions：

The generation device of scanning signal, including buffer, sync separator, the first APC circuits, voltage controlled oscillator, row point From circuit, the 2nd APC circuits, output device, row separator, field split circuit, the buffer inputs composite video signal, institute State buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device according to Secondary connection；The row separator is connected with sync separator, and the field split circuit connection, the field split circuit exports arteries and veins Punching, the signal of the field split circuit output pass through outer blanking；Crystal oscillator, the 2nd APC electricity are connected with voltage controlled oscillator Road will also receive line flyback pulse.

The external crystal oscillator of the present invention, crystal oscillator 500KHz, crystal oscillator form oscillating circuit with voltage controlled oscillator, produce 32 times of line frequencies Signal, through the formation horizontal pulse of row frequency dividing circuit, line synchronising signal conduct is taken out by synchronizing separator circuit after vision signal feeding The benchmark of row phase discriminator and line-pulse signal phase demodulation.Line synchronising signal is taken out field sync signal through field split circuit again and swept as field The reference signal retouched removes controlling filed frequency dividing circuit, makes field scan pulse and the audio video synchronization of output.Row signal after frequency dividing passes through again Second phase discriminator carries out phase bit comparison with line flyback pulse, then amplifies after phase shift through horizontal drive circuit, finally output row scanning arteries and veins Punching.

Further, the generation device of scanning signal, the row split circuit include resistance R1, resistance R2, resistance R3, electricity R4, electric capacity C1, electric capacity C2, triode V2 are hindered, resistance R1 one end is signal input part, and the base stage of its other end and triode V2 connects Connect, described electric capacity C1 one end is connected on the circuit that resistance R1 is connected with triode V2, its other end ground connection；The resistance R2 mono- 12V power supplys are terminated, its other end is connected with triode V2 emitter stage；The resistance R3 connects with electric capacity C2, the resistance R3 One end connection 12V power supplys at electric capacity C2 ends are connected, the other end at electric capacity C2 connection resistance R3 ends is connected to resistance R2 and triode On the circuit of V2 connections；The colelctor electrode of resistance R4 one end connecting triode V2, its other end ground connection；The resistance R4 and three It is signal output part on the circuit of pole pipe V2 connections.

Separated in synchronization transistor V2 emitter stage is (i.e. static in the case of no input signal added with RC timing circuits When), V is in zero-bias, or in order to improve separation sensitivity more slightly forward bias.When the composite color television of positive polarity is believed When number being added to through R1 in separated in synchronization transistor V2 base stage, the lock-out pulse part born in signal makes V2 turn on and be operated in put Big state, the synchronization pulse being then amplified on V2 collector load resistor R4.When V2 is turned on, its base stage electricity Direction is flowed as shown in solid arrow in figure.This electric current charges to electric capacity C2, and for the left negative right side just, charging voltage value is its charging polarity e2.E2 size is almost equal with the peak value e1 of lock-out pulse.C2 charging voltage is individual equivalent to having added for V2 emitter junction Reverse biased, so V2 cut-offs (because the amplitude of video signal portions is less than synchronizing signal amplitude) after synchronizing signal.

During V2 ends, C2 charging voltage will be discharged by resistance R2.Because R2 resistances are much larger than R3 resistance, institute Very slow with the velocity of discharge, V2 is always maintained at cut-off state before next synchronous pulse arrival.C2 discharge current direction As indicated by a dashed arrow in the figure.When next synchronous pulse arrives, the peak value of lock-out pulse turns on V2 again, and C2 is again It is electrically charged.Said process goes round and begins again, i.e. V2 is the peak value arrival moment conducting in synchronizing signal, and after lock-out pulse Cut-off, then obtains a succession of synchronization pulse in V2 colelctor electrode.This method is to utilize synchronizing signal and vision signal This feature of amplitude difference isolates synchronizing signal, and we are called amplitude separation.

Further, the generation device of scanning signal, the voltage controlled oscillator use ADF4360-7.

The present invention compared with prior art, has the following advantages and advantages：The present invention divides by buffer, synchronously From device, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device, row separator, field separation electricity Road improves the stability of scanning system.

Brief description of the drawings

Accompanying drawing described herein is used for providing further understanding the embodiment of the present invention, forms one of the application Point, do not form the restriction to the embodiment of the present invention.In the accompanying drawings：

Fig. 1 is schematic structural view of the invention；

Fig. 2 is row split circuit structural representation of the present invention.

Embodiment

For the object, technical solutions and advantages of the present invention are more clearly understood, with reference to embodiment and accompanying drawing, to this Invention is described in further detail, and exemplary embodiment of the invention and its explanation are only used for explaining the present invention, do not make For limitation of the invention.

Embodiment

As depicted in figs. 1 and 2, the generation device of scanning signal, including buffer, sync separator, the first APC circuits, Voltage controlled oscillator, row split circuit, the 2nd APC circuits, output device, row separator, field split circuit, the buffer inputs Composite video signal, the buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC Circuit, output device are sequentially connected；The row separator is connected with sync separator, the field split circuit connection, the field Split circuit exports pulse, and the signal of the field split circuit output passes through outer blanking；Crystal oscillator is connected with voltage controlled oscillator, The 2nd APC circuits will also receive line flyback pulse.

The row split circuit includes resistance R1, resistance R2, resistance R3, resistance R4, electric capacity C1, electric capacity C2, triode V2, Resistance R1 one end is signal input part, and its other end is connected with triode V2 base stage, and described electric capacity C1 one end is connected to resistance On the circuit that R1 is connected with triode V2, its other end ground connection；The resistance R2 mono- terminates 12V power supplys, its other end and three poles Pipe V2 emitter stage connection；The resistance R3 connects with electric capacity C2, one end connection 12V electricity at the resistance R3 connections electric capacity C2 ends Source, the other end at electric capacity C2 connection resistance R3 ends are connected on the circuit that resistance R2 is connected with triode V2；The resistance R4 mono- Hold connecting triode V2 colelctor electrode, its other end ground connection；It is defeated for signal on the circuit that the resistance R4 is connected with triode V2 Go out end.Voltage controlled oscillator uses ADF4360-7.

Above-described embodiment, the purpose of the present invention, technical scheme and beneficial effect are carried out further Describe in detail, should be understood that the embodiment that the foregoing is only the present invention, be not intended to limit the present invention Protection domain, within the spirit and principles of the invention, any modification, equivalent substitution and improvements done etc., all should include Within protection scope of the present invention.

Claims (3)

1. the generation device of scanning signal, it is characterised in that including buffer, sync separator, the first APC circuits, voltage-controlled shake Device, row split circuit, the 2nd APC circuits, output device, row separator, field split circuit are swung, the buffer inputs are compound to be regarded Frequency signal, it is the buffer, sync separator, the first APC circuits, voltage controlled oscillator, row split circuit, the 2nd APC circuits, defeated Go out device to be sequentially connected；The row separator is connected with sync separator, the field split circuit connection, the field split circuit Pulse is exported, the signal of the field split circuit output passes through outer blanking；It is connected with crystal oscillator on voltage controlled oscillator, described second APC circuits will also receive line flyback pulse.

2. the generation device of scanning signal according to claim 1, it is characterised in that the row split circuit includes resistance R1, resistance R2, resistance R3, resistance R4, electric capacity C1, electric capacity C2, triode V2, resistance R1 one end are signal input part, and its is another End is connected with triode V2 base stage, and described electric capacity C1 one end is connected on the circuit that resistance R1 is connected with triode V2, and its is another One end is grounded；The resistance R2 mono- terminates 12V power supplys, and its other end is connected with triode V2 emitter stage；The resistance R3 with Electric capacity C2 connects, one end connection 12V power supplys at the resistance R3 connections electric capacity C2 ends, the other end at electric capacity C2 connection resistance R3 ends It is connected on the circuit that resistance R2 is connected with triode V2；The colelctor electrode of resistance R4 one end connecting triode V2, its is another End ground connection；It is signal output part on the circuit that the resistance R4 is connected with triode V2.

3. the generation device of scanning signal according to claim 1, it is characterised in that the voltage controlled oscillator uses ADF4360-7。