CN1668116A - Identification signal detection circuit and secam color signal processing circuit - Google Patents
Identification signal detection circuit and secam color signal processing circuit Download PDFInfo
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- CN1668116A CN1668116A CN 200510052893 CN200510052893A CN1668116A CN 1668116 A CN1668116 A CN 1668116A CN 200510052893 CN200510052893 CN 200510052893 CN 200510052893 A CN200510052893 A CN 200510052893A CN 1668116 A CN1668116 A CN 1668116A
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Abstract
The invention provided an SECAM color signal processing circuit, capable of detecting and demodulating a high precision identification under a severe deteriorative conditions of weak field or noise in SECAM system reception. In addition to a code detection circuit 204 for detecting ident information, i.e. frequency component detection results S204, from a frequency component indicating the R-Y signal component and B-Y signal component of a chrominance subcarrier signal; an identification generating circuit 215 for generating a false identification S205 repeating reversal, each time a horizontal sync signal S121 is inputted by supplying the horizontal sync signal S121 anew and generating identification S106, by controlling the false identification S205 thus generated with a control signal S214 being outputted from a reversal direction generating circuit 216 at the post-stage; and a circuit 209 for making a decision as to whether the identification S106 agrees with the frequency component detection results S204 from the code detection circuit are provided.
Description
Technical field
The present invention relates to recognition signal deteching circuit that in the colour signal of the simulated television system of SECAM mode is handled, uses and the SECAM color-signal processing circuit that has used this identification signal detection circuit.
Background technology
The simulated television mode is according to its transmission means difference of area, in current NTSC mode, PCL mode and the practicality of SECAM mode.No matter in any mode, be luminance signal and colour subcarrier signal stack back transmission this point identical, but on the generation method of colour subcarrier signal, there are differences.Specifically, under the situation of NTSC mode or PAL mode, colour subcarrier signal is carried out the right angle bi-phase modulated, transmit R-Y signal, B-Y signal simultaneously, with respect to this, under the situation of SECAM mode, colour subcarrier signal is carried out the FM modulation, during each horizontal synchronization, sequential delivery R-Y signal, B-Y signal on each bar scan line.Therefore, the colour subcarrier signal in the SECAM mode has DR signal, the DB signal of the row of the row that is used to discern the R-Y signal and B-Y signal.The centre frequency of DR signal, DB signal is determined as follows.
DR：4.406MHz
DB：4.250MHz
And, in the SECAM mode that adopts transmission means as described above, compare with NTSC mode or PAL mode, carry out demodulation owing to can receive the most stable R-Y signal, B-Y signal for the distortion of transmission system, therefore do not crosstalk.
Below, use Figure 10 and Figure 11, the color-signal processing circuit of SECAM mode in the past is described.Figure 10 illustrates the structure of the color signal treatment circuit of SECAM in the past, and Figure 11 is the signal waveforms from the each several part output of in the past the color signal treatment circuit of SECAM.
In Figure 10, the 601st, the input terminal of input color subcarrier signal S601, the 602nd, detect the DR signal that is included in among the colour subcarrier signal S601 in this input terminal 601, DB signal, generate the colored clock circuit that only between the detection period of this each signal, becomes the colored synchronization pulse S602 of H level, the 603rd, if having color composition, colour subcarrier signal S601 intactly exports colour subcarrier signal S601, on the other hand, if in colour subcarrier signal S601, do not have color composition but black-and-white signal, then be to remove the inhibition circuit 603 that is mingled in the noise signal among this colour subcarrier signal S601.In addition, the 604th, make from the output signal S603 of above-mentioned inhibition circuit 603 postpone a horizontal synchronizing cycle (below, be called " 1H ".) the 1H delay circuit, the 606th, make the R-Y signal component of above-mentioned colour subcarrier signal be input to the R-Y demodulator circuit in order in the level row ON-OFF control circuit 605 of back, to control, the B-Y signal composition is input to the B-Y demodulator circuit, the circuit of the R-Y signal component of the above-mentioned colour subcarrier signal of generation identification and the identification signal S606 of B-Y signal composition.605 are based on above-mentioned identification signal S606, making becomes the R-Y demodulator circuit 607 that the R-Y signal component outputs to the back level all the time from the output signal S603 of above-mentioned inhibition circuit 603 with from the output S604 of above-mentioned 1H delay circuit 604, the B-Y signal composition outputs to the capable ON-OFF control circuit of the B-Y demodulator circuit 608 of back level all the time, the 609, the 610th, export in above-mentioned R-Y demodulator circuit 607 and B-Y demodulator circuit 608 demodulation the S607, the lead-out terminal of S608 of signal.
Secondly, the action of the SECAM color-signal processing circuit in the past with this structure is described with reference to Figure 11.
At first, if in input terminal 601 input color subcarrier signal S601, then colour subcarrier signal S601 is input in the colored clock circuit 602, also is input to simultaneously to suppress in the circuit 603.
In colored clock circuit 602, detect the DR signal, the DB signal that are included among the colour subcarrier signal S601, generate the only colored synchronization pulse S602 of output H level between the detection period of each DR, DB signal.This colour synchronization pulse S602 is that to have or not the color composition of colour subcarrier signal S601 with detection be the signal of purpose, and therefore can not differentiate the colour subcarrier signal S601 that be imported according to this signal S602 is the row of R-Y signal or the row of B-Y signal.
And, be input to from the colour subcarrier signal S601 of above-mentioned input terminal 601 and from the colored synchronization pulse S602 of above-mentioned colored synchronization pulse generative circuit 602 and suppress in the circuit 603, suppress in the circuit 603 at this, based on above-mentioned colored synchronization pulse S602, judge to have or not colour subcarrier signal S601 color composition.In colour subcarrier signal S601, there is not color composition when being judged to be when (be black and white broadcasting), control with removal and be mingled in noise among the above-mentioned colour subcarrier signal S601, chromatic noise does not take place when showing in image display device, on the other hand, when being judged to be in above-mentioned colour subcarrier signal S601 the chromatic colour composition, intactly export this colour subcarrier signal S601, carry out the processing of back one-level.
When the colour subcarrier signal S603 after handling from the inhibition of above-mentioned inhibition circuit 603 outputs supplies with terminal of row ON-OFF control circuit 605, after having postponed 1H part via 1H delay circuit 604, supply with another input terminal of this row ON-OFF control circuit 605.Here, with above-mentioned 1H delay circuit 604 the colour subcarrier signal S603 after suppressing to handle being postponed 1H partly is for the R-Y signal component and the B-Y signal composition that come in each 1H transmission are carried out demodulation process simultaneously.Handle by this, can in identical 1H, in image display device, show R-Y signal component and B-Y signal composition.
And then colour subcarrier signal S603 and above-mentioned colored synchronization pulse S602 after above-mentioned inhibition is handled supply to identification signal detection circuit 606.And, in identification signal detection circuit 606, in order to control above line ON-OFF control circuit 605, make all the time R-Y signal component guiding R-Y signal demodulating circuit 607, all the time B-Y signal composition guiding B-Y signal demodulator circuit 608, generate the R-Y signal component of the above-mentioned colour subcarrier signal of identification and the identification signal S606 of B-Y signal composition from above-mentioned signal S603, S602.
Here, further describe the generation method of above-mentioned identification signal S606.
Identification signal S606 discerns by each signal component of the DR signal from be included in the colour subcarrier signal S603 after the inhibition that suppresses circuit 603 outputs is handled, DB signal and generates.Specifically, the frequency content of colour subcarrier signal S603 after above-mentioned inhibition during promptly having DR signal, DB signal during the colored synchronization pulse S602 H level of judgement in supplying to above-mentioned identification signal detection circuit 606 is handled, discerning this frequency content is R-Y signal component or B-Y signal composition.
And, it is 4.406MHz that the judgement of the frequency content of above-mentioned colour subcarrier signal S603 utilizes DR signal, DB signal is 4.250MHz, from the centre frequency 4.328MHz of these signals (=(DR+DB)/2), the frequency content of differentiating the colour subcarrier signal S603 that is imported be high (+; Just) still low (; Negative) positive and negative differentiation, detect identification signal S606 from this court verdict.That is,, then mean it is the R-Y signal component,, then mean it is the B-Y signal composition if this frequency content is lower than centre frequency if the frequency content of colour subcarrier signal S603 is higher than centre frequency.
And, based on the above identification signal S606 that obtains like that, control row ON-OFF control circuit 605 make after being input to inhibition in this row ON-OFF control circuit 605 handles colour subcarrier signal S603 and from the some R-Y of the outputing to demodulator circuits 607 among the output S604 of 1H delay circuit 604, another outputs to B-Y demodulator circuit 608.Thus, from lead-out terminal 609,610 output simultaneously by demodulation R-Y signal S607 and B-Y signal S608.
According to above circuit structure, in each horizontal period, simultaneously demodulation R-Y signal and B-Y signal, in addition, even, also can suppress control for the frequency colour subcarrier signal of black and white broadcasting.
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The content of invention
But, under the situation of structure as described above, have following problem.
The 1st, in structure in the past, when in identification signal detection circuit 606, detecting identification signal S606, if the DR signal among the colour subcarrier signal S603 after identification is included in and suppress handles mistakenly, the frequency of DB signal then have the problem that the composition of R-Y signal after the demodulation, B-Y signal can not reproduce in image display device.
Promptly, under severe condition such as weak electric field such as forest area or noise, for the television broadcasting of SECAM mode being presented in the image display devices such as television set, need correctly receive colour subcarrier signal S601 with above-mentioned SECAM color-signal processing circuit 600, correctly reproduce R-Y signal, the B-Y signal composition that is included in this signal.At this moment, if in above-mentioned identification signal detection circuit 606, generate identification signal S606 mistakenly, in the ON-OFF control circuit of then being expert at 605, wrong signal is outputed to R-Y demodulator circuit 607 and B-Y demodulator circuit 608, because restituted signal correctly in this each demodulator circuit 607,608, therefore make the colored image quality aggravation of image, lack the colored definition of distinguishing, become the colored horizontal result who draws noise of appearance on the picture of above-mentioned image display device.
The 2nd, during the vertical flyback of medium such as in recent years video tape recorder or DVD device in, too much insert copy protection pulses, have the problem that generates identification signal S606 because of this copy protection pulses mistakenly.
Promptly; the demodulation of colour subcarrier signal S601 is handled based on colored synchronization pulse S602; if in medium, insert above-mentioned copy protection pulses; then in the synchronizing separator circuit of this color-signal processing circuit previous stage; when separating vertical synchronizing signal and horizontal-drive signal, the vision signal of being imported produces misoperation; when generating colored synchronization pulse S602 from colour subcarrier signal S601, detect the timing that this colour synchronization pulse S602 exists sometimes mistakenly.And the flase drop of this colour synchronization pulse S602 is surveyed the reason that very likely becomes the flase drop survey that is included in the identifying information among the colour subcarrier signal S601.Therefore; in this SECAM color-signal processing circuit; in medium, insert under the situation of copy protection pulses, also need the countermeasure circuit is set so that the situation that detects the timing that above-mentioned colored synchronization pulse S602 exists mistakenly because of this copy protection pulses does not take place.
The 3rd, be in the zone that mix to send of the signal of SECAM mode and PAL mode in transmission means, have when having received the signal of PAL mode, correctly the problem of restituted signal with SECAM coloured silk signal treatment circuit.
Promptly, in the SECAM color-signal processing circuit in the prior art, when having supplied with the colour subcarrier signal of PAL mode, since different in the SECAM mode with the modulator approach and the demodulation method of this colour subcarrier signal in the PAL mode, control therefore when the colour subcarrier signal of demodulation PAL mode, need be suppressed.Yet, in the color signal treatment circuit 600 of SECAM in the prior art, at the colour subcarrier signal S601 that is received is not have under the situation of black and white broadcasting of color composition, though can suppress control by suppressing circuit 603 by above-mentioned method, but under the situation of the colour subcarrier signal of having supplied with the PAL mode, owing in the colour subcarrier signal of this PAL mode, also have colored synchronization pulse, therefore in suppressing circuit 603, can not suppress control.Thereby, in the color signal treatment circuit of SECAM, under the situation of the colour subcarrier signal of having supplied with the PAL mode, need the Control Countermeasure circuit be set in this signal processing circuit inside demodulation process is not carried out.
The present invention finishes for solving above-mentioned problem, purpose is to provide only adds fairly simple circuit, just can more accurate and stably detect the identification signal detection circuit of the identification signal of SECAM colour signal, and the SECAM colour signal demodulation circuit that has utilized this identification signal detection circuit.
Identification signal detection circuit of the present invention receives the colour subcarrier signal of SECAM mode, detection is used to discern the identification signal of the R-Y signal component and the B-Y signal composition of this colour subcarrier signal, possesses: the frequency content that detects this SECAM mode colour subcarrier signal during the colored synchronization pulse in the colour signal interval of detecting R-Y signal component that expression obtains from the colour subcarrier signal of above-mentioned SECAM mode and B-Y signal composition still is low code detection circuit than intermediate frequency height; The trigger that overturns repeatedly when being included in each input level synchronizing signal is carrying out carrying out the identification signal generative circuit that the output after the logical calculated is exported as identification signal from the upset index signal of the upset of the output of this trigger from the output of this trigger and from the indication of the upset indication generative circuit output of back one-level; According to cycle of above-mentioned horizontal-drive signal, differentiate from the whether consistent consistent judging circuit of the signal of above-mentioned code detection circuit output and the identification signal of exporting from above-mentioned identification signal generative circuit; According to the differentiation result of above-mentioned consistent judging circuit, the output indication is from the upset indication generative circuit of the upset index signal of the upset of the identification signal of above-mentioned identification signal generative circuit output.
Thus, can stably detect high-precision identification signal in the reception of SECAM mode, even its result is when weak electric field etc. extremely under the harsh conditions, the colored horizontal noise etc. that draws can not take place on the picture of radiovisor yet, stably carries out demodulation.
In addition, in identification signal detection circuit of the present invention, above-mentioned upset index signal generative circuit is not exported above-mentioned upset index signal under the continuous consistent situation of the differentiation result of above-mentioned consistent judging circuit; Under, the inconsistent situation consistent repeatedly alternately continuously,, export above-mentioned upset index signal in this unanimity, the inconsistent number of occurrence moment greater than predefined number of times at above-mentioned court verdict; Under the continuous inconsistent situation of above-mentioned court verdict,, partly export the index signal of overturning at the one-period of above-mentioned horizontal-drive signal in the moment of this inconsistent number of times greater than predefined number of times.
Thus, in the reception of SECAM mode, can stably detect high-precision identification signal.
In addition, in identification signal detection circuit of the present invention, above-mentioned upset indication generative circuit from the rising edge of vertical synchronizing signal through after during predefined, export above-mentioned upset index signal.
In addition, SECAM apparatus for chrominance signal processing of the present invention possesses: when the colour subcarrier signal of SECAM mode is exported R-Y signal component and B-Y signal composition alternately, postpone the 1H delay circuit of horizontal-drive signal one-period part; Import above-mentioned colour subcarrier signal and horizontal-drive signal, detect the identification signal detection circuit of the identification signal of the R-Y signal component be used to discern this colour subcarrier signal and B-Y signal composition; Import the colour subcarrier signal of above-mentioned SECAM mode and the signal of exporting from above-mentioned 1H delay circuit,, export the capable ON-OFF control circuit of the R-Y signal component and the B-Y signal composition of this colour subcarrier signal simultaneously based on above-mentioned identification signal; The R-Y signal component of the above-mentioned colour subcarrier signal of demodulation and the R-Y demodulator circuit of B-Y signal composition and B-Y demodulator circuit; Use is from the identification signal and the horizontal-drive signal of above-mentioned identification signal detection circuit output, generate the inhibition circuit of inhibition signal of the demodulation process of above-mentioned R-Y demodulator circuit of control and B-Y demodulator circuit, above-mentioned identification signal detection circuit possesses: the frequency content that detects the colour subcarrier signal of this SECAM mode during the colored synchronization pulse in the colour signal interval of detecting R-Y signal component that expression obtains from the colour subcarrier signal of above-mentioned SECAM mode and B-Y signal composition still is low code detection circuit than centre frequency height; The trigger that overturns repeatedly when being included in each input level synchronizing signal carries out this to carry out the identification signal generative circuit that the output after the logical calculated is exported as identification signal from the upset index signal of the upset of the output of this trigger from the output of this trigger and from the indication of the upset indication generative circuit output of back one-level; According to cycle of above-mentioned horizontal-drive signal, differentiate from the signal of the above-mentioned code detection circuit output consistent judging circuit whether consistent with export identification signal from above-mentioned identification signal generative circuit; According to the differentiation result of above-mentioned consistent judging circuit, the output indication is from the upset indication generative circuit of the upset index signal of the upset of the identification signal of above-mentioned identification signal generative circuit output.
Thus, even mix in the zone that sends at the signal of SECAM mode or PAL mode, also can demodulation SECAM colour signal, even under the situation that has received the PAL signal mistakenly, also can be by suppressing the signal controlling demodulation process.
If according to identification signal detection circuit of the present invention, then owing to generate identification signal from horizontal-drive signal, whether differentiate this identification signal consistent with the signal that obtains from colour subcarrier signal in the code detection circuit, this differentiation result is reflected in the output of above-mentioned identification signal, therefore can stably supply with identification signal correctly, even its result when weak electric field or noise when strong etc. extremely under the harsh conditions, also can carry out reception, the demodulation process of radiovisor.
In addition; if according to identification signal detection circuit of the present invention; then because on the basis of above-mentioned horizontal-drive signal; also import vertical synchronizing signal; in certain scheduled time that the rising edge from vertical synchronizing signal begins; output for the detection signal that generates from horizontal-drive signal; therefore do not reflect above-mentioned differentiation result, can access during the vertical flyback that is not subjected to this vertical synchronizing signal or surpass during this vertical flyback and the more accurate and stable identification signal of the influence of the copy protection pulses that inserts.
In addition, if according to SECAM color-signal processing circuit of the present invention, then owing to use from the above-mentioned identification signal and the horizontal-drive signal of identification signal detection circuit output, control above-mentioned R-Y demodulator circuit and B-Y demodulator circuit demodulation process, therefore even when weak electric field or noise when strong etc. extremely under the harsh conditions, also can carry out the reception of television reception image device, demodulation process, in addition, even the signal in SECAM mode or PAL mode mixes in the zone that sends, also can demodulation SECAM colour signal, even when having received PAL mode signal mistakenly, also can be by SECAM signal controlling demodulation process.
Description of drawings
Fig. 1 is the figure of structure that the SECAM color-signal processing circuit of the invention process form 1 is shown.
Fig. 2 is the figure of structure of identification signal detection circuit that the SECAM color-signal processing circuit of the invention process form 1 is shown.
Fig. 3 is the figure of structure of inhibition circuit that the SECAM color-signal processing circuit of the invention process form 1 is shown.
Fig. 4 is the signal waveforms from the each several part output of the inhibition circuit of the invention process form 1.
Fig. 5 (a) is in the SECAM of the invention process form 1 color-signal processing circuit, from the differentiation result of consistent judging circuit output when consistent continuously, from the signal waveforms of the each several part output of identification signal detection circuit.
Fig. 5 (b) is in the SECAM of the invention process form 1 color-signal processing circuit, from the differentiation result of consistent judging circuit output when consistent, inconsistent repeatedly continuously alternately, from the signal waveforms of the each several part output of identification signal detection circuit.
Fig. 5 (c) is in the SECAM of the invention process form 1 color-signal processing circuit, and is continuous when inconsistent from the differentiation result of consistent judging circuit output, from the signal waveforms of the each several part output of identification signal detection circuit.
Fig. 6 is the figure of structure that the SECAM color-signal processing circuit of the invention process form 2 is shown.
Fig. 7 is the figure of structure of identification signal detection circuit that the SECAM color-signal processing circuit of the invention process form 2 is shown.
Fig. 8 (a) is the signal waveforms when having imported normal vision signal in the SECAM color-signal processing circuit in the invention process form 2.
Fig. 8 (b) is the signal waveforms when having imported the vision signal that comprises copy protection pulses in the color signal treatment circuit of the SECAM in the invention process form 2.
Fig. 9 is other the figure of structure that the SECAM color-signal processing circuit of the invention process form 2 is shown.
Figure 10 is the figure that the structure of SECAM color-signal processing circuit in the past is shown.
Figure 11 is the signal waveforms from the each several part output of in the past SECAM color-signal processing circuit.
Embodiment
Example 1
Below, the SECAM color-signal processing circuit of this example 1 is described.
The SECAM color-signal processing circuit of this example 1 generates identification signal from horizontal-drive signal, can stably obtain correct identification signal.
At first, use Fig. 1～Fig. 3 that the structure of the SECAM color-signal processing circuit of this example 1 is described.
Fig. 1 is the figure of structure that the SECAM color-signal processing circuit of this example 1 is shown, Fig. 2 is the figure that the detailed structure of identification signal detection circuit in the SECAM color-signal processing circuit of this example 1 is shown, and Fig. 3 is the figure that the structure of the inhibition circuit in the SECAM color-signal processing circuit of this example 1 is shown.
As shown in Figure 1, the SECAM color-signal processing circuit 100 of this example 1 comprises: the input terminal 101 of input color subcarrier signal S101; The input terminal 121 of input level synchronizing signal S121; Generate the colored synchronization pulse generative circuit 102 of colored synchronization pulse S102; Make above-mentioned colour subcarrier signal S101 postpone the 1H delay circuit 104 of 1H; Control and make, another is outputed to capable ON-OFF control circuit 105 in the B-Y demodulator circuit the some R-Y of the outputing to demodulator circuits among above-mentioned colour subcarrier signal S101 and the above-mentioned colour subcarrier signal S104 that postpones 1H; Detection is used to discern the identification signal detection circuit 106 of identification signal of R-Y signal component, the B-Y signal composition of colour subcarrier signal S101; The R-Y signal component of the above-mentioned colour subcarrier signal of demodulation and the R-Y demodulator circuit 107 of B-Y signal composition and B-Y demodulator circuit 108; Be controlled at the inhibition circuit 130 of the demodulation action in this each demodulator circuit 107,108 based on above-mentioned identification signal; Lead-out terminal 109,110.
Below, use Fig. 2 and Fig. 3 that above-mentioned identification signal detection circuit 106 and the detailed structure that suppresses circuit 130 are described.
At first, above-mentioned identification signal detection circuit 106 possesses the input terminal 201,202,203 of difference input level synchronizing signal S121, colored synchronization pulse S102 and colour subcarrier signal S101 as shown in Figure 2; With identical in the past, detect the frequency of the above-mentioned colour subcarrier signal S101 when above-mentioned colored synchronization pulse S102 is the H level, output represent this frequency ratio centre frequency height still be low testing result (below, be called " frequency display result ".) the code detection circuit 204 of S204; By making horizontal-drive signal S121 upset at each 1H by trigger 205, generate simulation identification signal S205, control this simulation identification signal S205 with the signal S214 that exports from the upset indication generative circuit 216 of back level, generate the identification signal generative circuit 215 of identification signal S106; Whether consistent differentiation from the frequency content testing result S204 of above-mentioned code detection circuit 204 outputs and the identification signal S106 that exports from last identification signal generative circuit 215 consistent judging circuit 209; According to the differentiation result of this unanimity judging circuit 209, the upset indication generative circuit 216 of the upset index signal S214 of the upset of the above-mentioned identification information signal S205 of output indication; Export the lead-out terminal 217 of above-mentioned identification signal S106.And, above-mentioned upset indication generative circuit 216, above-mentioned code detection circuit 204 are with identical in the past, use colored synchronization pulse S102 and colour subcarrier signal S101, carry out during this colour synchronization pulse S102 is the H level, promptly, have the detection of the frequency content of the colour subcarrier signal S101 during DR signal, the DB signal, the output frequency composition detection is S204 as a result.Specifically, utilize DR signal to be 4.250MHz for 4.406MHz, DB signal, from the centre frequency 4.328MHz of these signals (=(DR+DB)/2), the frequency content of differentiating the colour subcarrier signal S101 that is imported than above-mentioned centre frequency height (+; Just) still low (; Negative) positive and negative differentiation.If do like this, then in code detection circuit 204, if can detect frequency content among the colour subcarrier signal S101 is+(just) then mean it is the R-Y signal component, if-(bearing) then mean it is the identifying information of B-Y signal composition.In addition, here as frequency content testing result S204, if frequency content be+(just) then output " 1 ", if frequency content is-(bear) then export " 0 ".
Above-mentioned identification signal generative circuit 215 comprises: the trigger 205,206 that overturns repeatedly when each input level synchronizing signal S121; Horizontal-drive signal S121 and the upset index signal S214 from above-mentioned upset indication generative circuit 216 are carried out the AND door 207 of logical calculated; Above-mentioned trigger 205,206 outputs are carried out the EOR door 208 of logical calculated, the simulation identification signal S205 that generates from horizontal-drive signal S121 by above-mentioned trigger 205 and with AND door 207 logical calculated above-mentioned horizontal-drive signal S121 with indicate the result of calculation S206 of the upset index signal S214 of generative circuit 216 further to carry out logical calculated from above-mentioned upset at EOR door 208, export this result of calculation as identification signal S106.Here, be " 1 " then mean it is the R-Y signal component if establish in above-mentioned identification signal generative circuit 215 the identification signal S106 that generates, be the B-Y signal composition if " 0 " then means.And, general in the vision signal of SECAM mode owing to transmit from the R-Y signal component, therefore when generating above-mentioned identification signal S106, it is " 1 " that means the R-Y signal component that the simulation identification signal S205 of slave flipflop 205 initial outputs become.
Above-mentioned consistent judging circuit 209 is made of the EOR door that the identification signal S106 from the frequency content testing result S204 of above-mentioned code detection circuit 204 and generation in above-mentioned identification signal generative circuit 215 is carried out logical calculated, and S209 exports this logical calculated result as differentiating as a result.And, be located at the output " 0 " under the consistent situation of S204 as a result of above-mentioned identification signal S106 and said frequencies composition detection, output " 1 " under the inconsistent situation here.
Above-mentioned upset indication generative circuit 216 comprises: add up or tired subtracting from the differentiation of the above-mentioned consistent judging circuit 209 outputs up-down counter 210 of S209 as a result; Obtain count value S210 from this up-down counter 210 output, from the differential detection circuit 211 of the difference of the count value of the count value of this up-down counter output and previous output; Detection does not keep the read-around ratio of steady state value from the output valve S211 of this differential detection circuit 211, at the 1st amplitude limit testing circuit 212 of this read-around ratio greater than the moment output signal S212 of predefined number of times; When from the count value S210 of above-mentioned up-down counter 210 outputs during greater than predefined value, the 2nd amplitude limit testing circuit 213 of output signal S213 during 1H only; Output S212, S213 from above-mentioned the 1st, the 2nd amplitude limit testing circuit 212,213 are carried out logical calculated, export the OR circuit 214 of this result of calculation as above-mentioned upset index signal S214.Here, be located in the above-mentioned upset indication generative circuit 216, if represent " 0 " of " unanimity " as above-mentioned differentiation S209 input as a result, then in above-mentioned up-down counter 210, tire out and subtract, if represent " 1 " of " inconsistent " as above-mentioned differentiation S209 input as a result, then in this up-down counter 210, add up,, then export " 1 " from above-mentioned the 1st, the 2nd amplitude limit testing circuit 212,213 as signal S212, S213 if respectively greater than predefined value.
Like this, in the identification signal detection circuit 106 of this example 1, in above-mentioned upset indication generative circuit 216, accept to differentiate the consistent of frequency content testing result S204 that detects by code detection circuit 204 and the simulation identification signal S205 that generates from horizontal-drive signal S121, inconsistent differentiation result, the result is corresponding with this differentiation, based on count value S210 from up-down counter output, generation makes the upset index signal S214 of above-mentioned simulation level signal S205 upset, therefore, can stably supply with the correct identification signal S106 that has considered by the frequency content testing result of code detection circuit 204 detections.
Secondly, above-mentioned inhibition circuit 130 possesses the input terminal 131 of input identification signal S106 as shown in Figure 3; The input terminal 132 of input level synchronizing signal S121; Make the trigger 133 of this identification signal S106 displacement 1H; The trigger 134 of the further displacement 1H of identification signal S133 of 1H that made this displacement; Output S133, the S134 of this trigger 133,134 are carried out the ENOR circuit 135 of logical calculated.And, based on identification signal S106, generate the inhibition signal S135 of the demodulation process action of control demodulator circuit 107,108 from above-mentioned identification signal detection circuit 106 outputs.
Below, the action of using Fig. 4 and Fig. 5 explanation to have the SECAM signal processing circuit 100 of said structure.Fig. 4 is an example from the signal waveforms of the each several part output of the inhibition circuit of this example 1, in addition, Fig. 5 is the signal waveforms from the each several part output of the identification signal detection circuit of this example 1, Fig. 5 (a) illustrates the consistent continuously situation from the differentiation result of consistent judging circuit output, Fig. 5 (b) illustrates consistent repeatedly alternately continuously, the inconsistent situation of differentiation result from consistent judging circuit output, and Fig. 5 (c) illustrates from the continuous inconsistent situation of result of determination of consistent judging circuit output.
At first, colour subcarrier signal S101 and horizontal-drive signal S121 are input to input terminal 101,121 respectively.Colour subcarrier signal S101 is input to colored synchronization pulse generative circuit 102, in above-mentioned colored synchronization pulse generative circuit 102, detection is included in DR signal, the DB signal among the colour subcarrier signal S101, generates and export the only colored synchronization pulse S102 of output H level between the detection period of each DR, DB signal.
In addition, when above-mentioned colour subcarrier signal S101 supplies to terminal of capable ON-OFF control circuit 105, delayed time after the 1H part, supplied to another input terminal of this row ON-OFF control circuit 105 through 1H delay circuit 104.Here, making colour subcarrier signal S101 postpone 1H by above-mentioned 1H delay circuit 104 is for R-Y signal component and the B-Y signal composition that sends at each 1H carried out demodulation process simultaneously, handle by this, can in identical 1H, on image display device, show R-Y signal component and B-Y signal composition.
And then colour subcarrier signal S101 supplies to identification signal detection circuit 106 with the above-mentioned colored synchronization pulse S102 of generation in above-mentioned colored synchronization pulse generative circuit 102 and the horizontal-drive signal S121 that imports from input terminal 121.So, in identification signal detection circuit 106, output by means of above-mentioned signal S101, S102, S121 control above line ON-OFF control circuit 105, generate all the time R-Y signal component guiding R-Y signal demodulating circuit 107, all the time the identification signal S106 of B-Y signal composition guiding B-Y signal demodulator circuit 108.Thus, the R-Y signal S107 and the B-Y signal S108 that can export simultaneously by demodulation suitably from lead-out terminal 109,110.
Above-mentioned identification signal S106 also is output to and suppresses circuit 130.In above-mentioned inhibition circuit 130, remove beyond the identification signal S106, input level synchronizing signal S121 also, when importing this horizontal-drive signal S121 at every turn, with ENOR door 135 the made above-mentioned identification signal S106 displacement signal S133 of 1H and displacement the signal S134 of 2H carry out logical calculated, control the demodulation process action of above-mentioned R-Y demodulator circuit 107 and B-Y demodulator circuit 108 according to inhibition signal S135 as its logical calculated result.That is, in this example 1, in suppressing circuit 130, judge whether alternatively output " 1 " and " 0 " of identification signal S106, under the continuous situation of identical value, be judged as and detect identification signal mistakenly, do not carrying out demodulation process in this period.For example at this, be under the situation of consecutive identical value in the value of identification signal S106, as suppressing signal S135 output " 1 ", under the situation of mutual output " 0 " and " 1 ", export " 0 " as suppressing signal S135.And, when this inhibition signal S135 is " 0 ", be judged as and have colour signal, carry out the demodulation process action, when being " 1 ", be judged as and do not have color composition (be black and white broadcasting), stop the demodulation process action, make chromatic noise (with reference to Fig. 4) does not take place on the picture of image display device.
Here, describe the detection of the relevant identification signal S106 that is exported from above-mentioned identification signal detection circuit 106 in detail with reference to Fig. 5.
At first, the colored synchronization pulse S102 and the colour subcarrier signal S101 that are input to input terminal 202,203 respectively are input to code detection circuit 204, in this code detection circuit 204, carry out as described above during above-mentioned colored synchronization pulse S102 is the H level, promptly have the detection of the frequency content of the colour subcarrier signal S101 during DR signal, the DB signal, the output frequency composition detection is S204 as a result.
In the past, S204 is used as identification signal this frequency content testing result, go the control of ON-OFF control circuit, but under the mal-condition when weak electric field etc., sometimes flase drop (is for example surveyed this frequency content result in code detection circuit 204, with reference to Fig. 5 (b)), the colored horizontal noise that draws appears in its result on the picture of television receiver.
Therefore, in the SECAM of this example 1 colour signal demodulation circuit 100, in order more correctly stably to obtain above-mentioned identification signal, in above-mentioned identification signal generative circuit 215, when each input level synchronizing signal S121, make the signal upset with trigger 205, generate simulation identification signal S205, and then, export as identification signal S106 this simulation identification signal S205 with based on the result that the signal S206 of upset index signal S214 slave flipflop 206 outputs of upset indication generative circuit 216 outputs of back level has carried out logical calculated.And, whether differentiate this identification signal S106 by consistent judging circuit 209 consistent with the frequency content testing result S204 that is detected by above-mentioned code detection circuit 204, this differentiation as a result S209 output to above-mentioned upset indication generative circuit 216, from this differentiation as a result S209 generate above-mentioned upset index signal S214, be input to above-mentioned identification signal generative circuit 215, make and when generating above-mentioned identification signal S106, consider this differentiation S209 as a result.
Below, be divided into three kinds of situations, specifically describe.
At first,, illustrate in above-mentioned consistent judging circuit 209 that the said frequencies composition detection is the situation of S204 consistent all the time with identification signal S106 (differentiating S209=" 0 " as a result) as a result with reference to Fig. 5 (a) as the 1st kind of situation.
The 1st kind of situation, promptly above-mentioned differentiation under the situation of S209 unanimity, owing to mean that the identification signal S106 that generates from horizontal-drive signal S121 is correct, does not therefore need to make identification signal S106 upset as a result.So in this case, upset indication generative circuit 216 is not exported the upset index signal S214 (upset index signal S214=" 0 ") of indication upset.
If below be described in detail, then from the differentiation of above-mentioned consistent judging circuit 209 outputs as a result S209 output to above-mentioned upset indication generative circuit 216, in up-down counter 210, continue counting.Under the 1st kind of situation, as differentiating as a result S209 because output " 0 " all the time, therefore from the tired count value S210 (with reference to the S210 of Fig. 5 (a)) that has subtracted of up-down counter 210 outputs.
Above-mentioned count value S210 outputs to differential detection circuit 211, obtains this count value and difference value S211 from the previous count value of above-mentioned up-down counter 210 outputs.Then, this difference value S211 is input to the 1st amplitude limit testing circuit 212, in this circuit 212, detects the read-around ratio that difference value S211 does not keep steady state value, exports " 1 " if this number of times reaches predefined value.Here, because above-mentioned differentiation S209 as a result is " 0 " all the time, and because above-mentioned difference value S211 becomes " 1 " (with reference to S211 of Fig. 5 (a)) all the time, therefore the signal S212 from above-mentioned the 1st amplitude limit testing circuit 212 is " 0 " (with reference to S212 of Fig. 5 (a)) all the time.
On the other hand, above-mentioned count value S210 also outputs to the 2nd amplitude limit testing circuit 213, in this circuit 213, if above-mentioned count value S210 reaches predefined certain value, and then output " 1 " during 1H.Here, as described above, because above-mentioned count value S210 tired subtracting in up-down counter 210, therefore can be not bigger than predefined value in the 2nd amplitude limit testing circuit 213, output " 0 ".
Then, be output to OR door 214, carry out logical calculated, output to above-mentioned up-down counter 210 and above-mentioned identification signal generative circuit 215 as the upset index signal S214 of this result of calculation from the output of above-mentioned each amplitude limit testing circuit 212,213.Here, because from each amplitude limit testing circuit 212,213 output all is " 0 ", therefore above-mentioned upset index signal S214 becomes " 0 " (with reference to S214 of Fig. 5 (a)), for above-mentioned identification signal generative circuit 215, do not export the indication that makes above-mentioned simulation identification signal S205 upset, output " 0 " all the time in the AND of this identification signal generative circuit 215 door 207, therefore slave flipflop 206 is exported " 0 " (with reference to S206 of Fig. 5 (a)), its result is from the identification signal S106 output and the identical signal (with reference to the S106 of Fig. 5 (a)) of simulation identification signal S205 of EOR door 208 outputs.
Secondly, as the 2nd kind of situation, illustrate in above-mentioned consistent judging circuit 209 that with reference to Fig. 5 (b) the said frequencies composition detection is the situation of S204 consistent repeatedly, inconsistent continuously with identification signal S106 (differentiating as a result, S209 becomes " 0 ", " 1 ", " 0 ", " 1 " ...) as a result.
The 2nd kind of situation, promptly above-mentioned differentiation consistent repeatedly continuously, the inconsistent situation of S209 as a result mean in above-mentioned code detection circuit 204 and have carried out the flase drop survey.So, in this case, make identification signal S106 become " 0 " (after B point of Fig. 5 (b)) continuously, suppress in the circuit 130, control and make that stopping demodulation process in each demodulator circuit 107,108 moves in the back level that with this identification signal S106 is input.
If below at length the narration, if from the differentiation of above-mentioned consistent judging circuit 209 outputs as a result the value of S209 begin mutual output " 0 " and " 1 " (A point of Fig. 5 (b)), then export the count value S210 (with reference to the S210 of Fig. 5 (b)) that has subtracted repeatedly, added from the up-down counter 210 of above-mentioned upset indication generative circuit 216.
Above-mentioned count value S210 outputs to differential detection circuit 211, obtains the difference value S211 of this count value and previous count value.Then, this difference value S211 is input to the 1st amplitude limit testing circuit 212, in this circuit 212, detects the read-around ratio that difference value S211 does not keep steady state value, exports " 1 " if this number of times reaches predefined number of times.For example at this, because above-mentioned differentiation is S209 " 0 " and " 1 " continuously repeatedly as a result, therefore above-mentioned difference value S211 exports " 1 " and " 1 " (with reference to S211 of Fig. 5 (b)) alternately, in above-mentioned the 1st amplitude limit testing circuit 212, " 1 " repeatedly of above-mentioned difference value S211 and " 1 " if number of times reach predefined number of times (being 2 times) here, then from above-mentioned the 1st amplitude limit testing circuit 212 output " 1 " (B points of Fig. 5 (b)).
On the other hand, above-mentioned count value S210 also outputs to the 2nd amplitude limit testing circuit 213, in this circuit 213, exports " 1 " if above-mentioned count value S210 reaches predefined value.Here, as described above, because above-mentioned count value S210 subtracts, adds computing repeatedly, therefore above-mentioned count value can be not bigger than predefined value in above-mentioned the 2nd amplitude limit testing circuit 213 (be here+4), output " 0 " all the time.
Then, be output to OR door 214 from the output of above-mentioned each amplitude limit testing circuit 212,213 and carry out logical calculated, output to above-mentioned up-down counter 210 and above-mentioned identification signal generative circuit 215 as the upset index signal S214 of this result of calculation.For example at this, inconsistent from the frequency content testing result S204 of code detection circuit 204 outputs with simulation identification signal S205, then be judged as and in the 1st amplitude limit testing circuit 212, carried out flase drop survey (the B point of Fig. 5 (b)), the output S212 of the 1st amplitude limit testing circuit 212 becomes " 1 ", aspect in addition, because the output S213 of the 2nd amplitude limit testing circuit 213 at this moment is " 0 ", therefore above-mentioned upset index signal S214 becomes " 1 " (with reference to S214 of Fig. 5 (b)), for above-mentioned identification signal generative circuit 215, the upset index signal of the upset of above-mentioned simulation identification signal S205 is indicated in output from above-mentioned upset indication generative circuit 216.In above-mentioned identification signal generative circuit 215, owing in AND door 207, import the upset index signal S214 of " 1 " all the time, therefore slave flipflop 206 outputs with from the identical signal of the simulation identification signal S205 of above-mentioned trigger 205 (with reference to the S206 of Fig. 5 (b)), its result exports " 0 " (with reference to Fig. 5 (b) S106) continuously as the identification signal S106 from 208 outputs of EOR door.And, imported the inhibition circuit 130 of this identification signal S106 owing to, therefore in each demodulator circuit 107,108, stop the demodulation process action as suppressing signal S135 output " 1 ".
As the 3rd kind of situation, illustrate in above-mentioned consistent judging circuit 209 that with reference to Fig. 5 (c) the said frequencies composition detection is the situation of S204 and identification signal S106 inconsistent all the time (differentiating S209=" 1 " as a result) as a result.
The 3rd kind of situation, be that above-mentioned differentiation is as a result under the continuous inconsistent situation of S209, since anti-phase fully from the identification signal S106 that horizontal-drive signal S121 generates with the frequency content testing result S204 that exports from above-mentioned code detection circuit 204, therefore need make identification signal S106 upset so that consistent with frequency content testing result S204 from above-mentioned code detection circuit 204.Thereby, in this case, indicate only output switching activity index signal S214 (upset index signal S214=" 1 ") during 1H of generative circuit 216 from upset.
If below be described in detail, then from the differentiation of above-mentioned consistent judging circuit 209 outputs as a result S209 output to above-mentioned upset indication generative circuit 216, counting in up-down counter 210.Here, because S209 exports " 1 " all the time as differentiating as a result, the therefore count value S210 (with reference to the S210 of Fig. 5 (c)) that has added up from up-down counter 210 outputs.
Above-mentioned count value S210 outputs to differential detection circuit 211, obtains the difference value S211 of this count value and previous count value.Then, this difference value S211 is input to the 1st amplitude limit testing circuit 212, in this circuit 212, detects the read-around ratio that difference value S211 does not keep steady state value, exports " 1 " if this number of times reaches predefined number of times.Here and since above-mentioned differentiation as a result S209 be " 1 " all the time, therefore above-mentioned difference value S211 also becomes " 1 " (with reference to S211 of Fig. 5 (c)) all the time, as the signal S212 output " 0 " from above-mentioned the 1st amplitude limit testing circuit 212.
On the other hand, above-mentioned count value S210 also outputs to the 2nd amplitude limit testing circuit 213, in this circuit 213, exports " 1 " if this count value S210 reaches predefined value.Here, because above-mentioned count value S210 is the value that has added up, if therefore surpass predetermined value (being 4) (the C point of Fig. 5 (c)) here, output " 1 " (with reference to S213 of Fig. 5 (c)) then.
Then, be output to OR door 214 from the output of above-mentioned amplitude limit testing circuit 212,213 and carry out logical calculated, output to above-mentioned up-down counter 210 with above-mentioned identification signal generative circuit 215 as the upset index signal S214 of this result of calculation.Here, owing to are " 0 ", are " 1 " from the output S213 of the 2nd amplitude limit testing circuit 213 from the output S212 of the 1st amplitude limit testing circuit 212, therefore above-mentioned upset index signal S214 output " 1 " (with reference to Fig. 5 (c) S214) during 1H only.In above-mentioned identification signal generative circuit 215, owing to during 1H, export " 1 " to AND door 207, therefore slave flipflop 206 is exported " 1 " (with reference to S206 of Fig. 5 (c)) during 1H, after having exported this upset index signal S214 (after the D point of Fig. 5), the signal that simulation identification signal S205 has been overturn as identification signal S106 from EOR door 208 outputs (with reference to the S106 of 5 (c)).
Like this, if according to this example 1, then in identification signal detection circuit 106, remove according to colored synchronization pulse S102 and colour subcarrier signal S101, detect the frequency content of this colour subcarrier signal S101, the output frequency composition detection beyond the code detection circuit 204 of S204, also possesses by up-down counter 210 as a result, the upset indication generative circuit 216 that differential detection circuit the 211, the 1, the 2nd amplitude limit testing circuit 212,213 and OR circuit 214 constitute; By the trigger 205,206 that overturns repeatedly when the each input level synchronizing signal S121, the identification signal generative circuit 215 that AND door 207 and EOR door 208 constitute; Whether consistent detection from the conduct of above-mentioned code detection circuit 204 outputs said frequencies composition detection S204 and the identification signal S106 that exports from above-mentioned identification signal detection circuit 106 the consistent judging circuit 209 as a result of identification signal in the past, because according to from the differentiation of above-mentioned consistent judging circuit 209 S209 as a result, therefore the output indication can provide correct and stable identification signal S106 from the upset index signal S214 of the upset of the identification signal S106 of above-mentioned identification signal generative circuit 215 outputs.
In addition, if according to this example 1, then above-mentioned such identification signal S106 that generates is input to the inhibition circuit 130 that suppresses to control, according to this identification signal S106, generate the action of control demodulation process and suppress signal S135, therefore the colour subcarrier signal S101 in being input to this SECAM color-signal processing circuit 100 does not have under the situation of black and white broadcasting of color composition, certainly can control makes chromatic noise not take place, even having supplied with is not under the situation of signal of colored minus carrier frequency signal of SECAM mode, in suppressing circuit 130, also can suppresses control and make chromatic noise not take place.Its result, even mix in the zone that sends at the signal of SECAM mode or PAL mode, also can demodulation SECAM colour signal, even under the situation that has received the PAL signal mistakenly, also can suppress control.
Example 2
Below, the SECAM color-signal processing circuit of this example 2 is described.
In this example 2, in the generation of identification signal, use vertical synchronizing signal, be not subjected to during the vertical flyback or surpass the influence of the copy protection pulses that inserts between this vertical retrace line interval, obtain more accurate and stable identification signal.
At first, use Fig. 6 and Fig. 7, the structure of the SECAM color-signal processing circuit of this example 2 is described.Fig. 6 illustrates the structure of the SECAM color-signal processing circuit in this example 2, and Fig. 7 illustrates the detailed structure of the identification signal detection circuit in the SECAM color processing signal of this example 2.
As shown in Figure 6, the SECAM color-signal processing circuit 300 in this example 2 is removed beyond the input terminal 101,121 of input color subcarrier signal S101 and horizontal-drive signal S121, also possesses the input terminal 301 of input vertical synchronizing signal S301.
And, be input to identification signal detection circuit 306 from the vertical synchronizing signal S301 of above-mentioned input terminal 301 inputs, in this identification signal detection circuit 306, based on above-mentioned horizontal-drive signal S121, colored synchronization pulse S102 and vertical synchronizing signal S301, detect identification signal S306 from above-mentioned colour subcarrier signal S101.
If below at length describe, then the identification signal detection circuit 306 of this example 2 shown in 7, possesses the input terminal 201,202,203,301 of input level synchronizing signal S121, colored synchronization pulse S102, colour subcarrier signal S101 and vertical synchronizing signal S301 respectively as shown; With identical in the past, the frequency content of the above-mentioned colour subcarrier signal S103 when the above-mentioned colored synchronization pulse S102 of output expression is the H level still is the code detection circuit 204 of low frequency content testing result S204 than centre frequency height; Identification signal generative circuit 415; Consistent judging circuit 209; Upset indication generative circuit 416.
Here, in recent years, insert copy protection pulses at medium such as video tape recorder or DVD equipment, generally this copy protection pulses inserts (with reference to Fig. 8 (a) and (b)) mostly between vertical retrace line interval.Therefore, especially the reliability of the frequency content testing result S204 that exports of the code detection circuit 204 in during the permission of vertical synchronizing signal is low, therefore in the structure of this example 2, in during the permission of vertical synchronizing signal, make not to be input to identification signal generative circuit 415 from the upset index signal S414 of upset indication generative circuit 416 outputs.
Specifically, in above-mentioned identification signal generative circuit 415, remove beyond the structure of above-mentioned example 1, NOT door 417 also be set, make during the permission of vertical synchronizing signal S301 in, do not allow trigger 206 move (S206=" 0 ").Thus, during vertical synchronizing signal S301 permission, trigger 206 is stopped, during the permission of this vertical synchronizing signal S301, make the permission signal S306 output that only depends on horizontal-drive signal S121, promptly from the simulation identification signal S205 of trigger 205 from this identification signal generative circuit 415.
In addition; in above-mentioned upset indication generative circuit 416; remove beyond the structure of above-mentioned example 1; the 3rd amplitude limit testing circuit 418 is set to make in this up-down counter 401; the quantity of the horizontal-drive signal S121 that counting is imported during vertical synchronizing signal S301; till this count value S418 is greater than predefined value; do not export count value S410 from above-mentioned up-down counter 410; even after the non-permission of vertical synchronizing signal S301; since the influence of copy protection pulses etc. be easy in the disorderly timing (during the E with reference to Fig. 8 (b)); also make the 1st; the 2nd amplitude limit testing circuit 212; 213 do not move, and stop the output from the upset index signal S414 of upset indication generative circuit 416.
Like this; in this example 2; remove beyond the structure of above-mentioned example 1; owing to also in above-mentioned identification signal generative circuit 415, NOT door 417 is set; make during vertical synchronizing signal S301 permission; trigger 206 does not move; and in above-mentioned upset indication generative circuit 416, the 3rd amplitude limit testing circuit 418 is set; in making during later predefined of the above-mentioned horizontal-drive signal S301 of input; not from up-down counter 410 output count value S410; the 1st; the 2nd amplitude limit testing circuit 212; 213 do not move; therefore when generating identification signal S306; can not be subjected to export more accurate and stable identification signal during the vertical flyback or surpass the influence of the copy protection pulses that inserts between this vertical retrace line interval.
In addition, because above-mentioned such permission signal S106 that generates is input to the inhibition circuit 130 that suppresses to control, according to this identification signal S106, generate the inhibition signal S135 of control demodulation process action, therefore at demodulator circuit 107, when carrying out in 108 the action of colour subcarrier signal S101 demodulation process, colour subcarrier signal S101 in being input to this SECAM color-signal processing circuit 300 does not have can be controlled to certainly under the situation of black and white broadcasting of color composition chromatic noise does not take place, even having supplied with is not under the situation of signal of colour subcarrier signal of SECAM mode, also can in suppressing circuit 130, suppresses control and make chromatic noise not take place.
In addition, in this example 2, supply level synchronizing signal S121 in suppressing circuit 130, by the inhibition control during the comparison of the signal of 2 triggers output can be carried out horizontal synchronization, and then as shown in Figure 9,, suppresses in the circuit 130 vertical synchronizing signal S301 the inhibition control in then can carrying out during the vertical synchronization if also supplying to.That is, in radiovisor, can carry out the inhibition control of each picture, can distinguish with the unit control and the clear and definite look of a picture.
SECAM color-signal processing circuit of the present invention is as in TV signal such as forest areas being zone under the mal-conditions such as weak electric field or noise, perhaps the signal of different modes mixes in the zone that sends, can stably detect correct identification signal, can be in radiovisor received television signal correctly, the circuit that carries out demodulation process is very useful.
Claims (5)
1. identification signal detection circuit, this identification signal detection circuit receives the colour subcarrier signal of SECAM mode, detects the identification signal of the R-Y signal component and the B-Y signal composition that are used to discern this colour subcarrier signal, possesses:
The frequency content that detects this SECAM mode colour subcarrier signal during the colored synchronization pulse in the colour signal interval detecting R-Y signal component that expression obtains from the colour subcarrier signal of above-mentioned SECAM mode and B-Y signal composition still is low code detection circuit than centre frequency height;
The trigger that overturns repeatedly when being included in each input level synchronizing signal is carrying out the identification signal generative circuit that the output after the logical calculated is exported as identification signal from the upset index signal of the upset of the output of this trigger from the output of this trigger and from the indication of the upset indication generative circuit output of back one-level;
According to cycle of above-mentioned horizontal-drive signal, differentiate from the whether consistent consistent judging circuit of the signal of above-mentioned code detection circuit output and the identification signal of exporting from above-mentioned identification signal generative circuit; And
According to the differentiation result of above-mentioned consistent judging circuit, the output indication is from the upset indication generative circuit of the upset index signal of the upset of the identification signal of above-mentioned identification signal generative circuit output.
2. identification signal detection circuit according to claim 1 is characterized in that:
Above-mentioned upset index signal generative circuit is not exported above-mentioned upset index signal under the continuous consistent situation of the differentiation result of above-mentioned consistent judging circuit; Under, the inconsistent situation consistent repeatedly alternately continuously, become greater than the moment of predefined number of times, export above-mentioned upset index signal in this unanimity, the inconsistent number of occurrence at above-mentioned court verdict; Under the continuous inconsistent situation of above-mentioned court verdict,, partly export the index signal of overturning at the one-period of above-mentioned horizontal-drive signal in the moment of this inconsistent number of times greater than predefined number of times.
3. identification signal detection circuit according to claim 1 is characterized in that:
Above-mentioned upset indication generative circuit from the rising edge of vertical synchronizing signal through after during predefined, export above-mentioned upset index signal.
4. SECAM signal processing circuit possesses:
When the colour subcarrier signal of SECAM mode is exported R-Y signal component and B-Y signal composition alternately, postpone the 1H delay circuit of horizontal-drive signal one-period;
Import above-mentioned colour subcarrier signal and horizontal-drive signal, detect the identification signal detection circuit of the identification signal of the R-Y signal component be used to discern this colour subcarrier signal and B-Y signal composition;
Import the colour subcarrier signal of above-mentioned SECAM mode and the signal of exporting from above-mentioned 1H delay circuit,, export the capable ON-OFF control circuit of the R-Y signal component and the B-Y signal composition of this colour subcarrier signal simultaneously based on above-mentioned identification signal;
The R-Y signal component of the above-mentioned colour subcarrier signal of demodulation and the R-Y demodulator circuit of B-Y signal composition and B-Y demodulator circuit; And
Use generates the inhibition circuit of the inhibition signal of the demodulation process of controlling above-mentioned R-Y demodulator circuit and B-Y demodulator circuit, wherein from the identification signal and the horizontal-drive signal of above-mentioned identification signal detection circuit output
Above-mentioned identification signal detection circuit possesses:
Detect the colour signal interval detecting R-Y signal component that expression obtains from the colour subcarrier signal of above-mentioned SECAM mode and B-Y signal composition colored synchronization pulse during the frequency content of this SECAM mode colour subcarrier signal still be low code detection circuit than centre frequency height;
The trigger that overturns repeatedly when being included in each input level synchronizing signal is carrying out the identification signal generative circuit that the output after the logical calculated is exported as identification signal from the upset index signal of the upset of the output of this trigger from the output of this trigger and from the indication of the upset indication generative circuit output of back one-level;
According to cycle of above-mentioned horizontal-drive signal, differentiate from the signal of the above-mentioned code detection circuit output consistent judging circuit whether consistent with export identification signal from above-mentioned identification signal generative circuit; And
According to the differentiation result of above-mentioned consistent judging circuit, the output indication is from the upset indication generative circuit of the upset index signal of the upset of the identification signal of above-mentioned identification signal generative circuit output.
5. SECAM composition signal processing circuit according to claim 4 is characterized in that:
Control make above-mentioned inhibition circuit the rising edge from vertical synchronizing signal passed through predefined during after, carry out the demodulation process of above-mentioned R-Y demodulator circuit and B-Y demodulator circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004058016A JP2005252483A (en) | 2004-03-02 | 2004-03-02 | Identification detection circuit and secam color signal processing circuit employing the identification detection circuit |
| JP2004058016 | 2004-03-02 |
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| CN1668116A true CN1668116A (en) | 2005-09-14 |
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