KR100301049B1 - Apparatus and method for identifying multi-standard - Google Patents

Abstract

A multi-broadcasting standard identification apparatus capable of identifying a multi-broadcasting standard of a color television using a frequency of a color burst signal digitally determined at a high speed. The analog / digital converter of the apparatus samples an analog composite video signal having information on a color burst having a frequency f _C , converts the sampled analog composite video signal into a digital composite video signal, and outputs sampling values. The first and second frequent oscillation signals having an oscillation frequency f _a and having a phase difference of 90 ° with each other, respectively, and the low-pass filter low-pass filters the multiplied results, (Z) between f _c and f _a using the pass-filtered results, and the identification signal detector determines Z the reference value adaptively adjusted in response to the identification signals previously used to identify the multiple broadcast standard Comparing each of the compared results with the levels of the currently compared results and determining whether each of the compared results is maintained at the same level for a first predetermined time, And outputs the discriminated results as identification signals. The autonomous oscillator adjusts f _a in response to the identification signals, and outputs first and second frequent oscillation signals having the adjusted f _a And the multiple broadcast standard is identified according to the logical states of the identification signals.

Description

[0001] Apparatus and method for identifying multi-standard [

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a color television receiver, and more particularly, to a multiple broadcasting standard identification apparatus and method capable of digitally identifying a multi standard of a color television receiver at a high speed.

In general, the multi-broadcasting standard identification apparatus determines how many times the frequency of the sine wave color burst signal included in the analog composite video signal is a frequency, and identifies the multiple broadcasting standard corresponding to the determined frequency. That is, the multi-broadcasting standard identification apparatus identifies the multi-broadcasting standard by using the fact that the frequency of the color burst signal is different according to the multi-broadcasting standard. These multicolor television broadcast standards generally include NTSC, PAL, and SECAM broadcast standards.

Such a conventional multi-broadcasting standard identification apparatus is disclosed in U.S. Patent No. 5,192,997. The conventional multi-broadcasting standard identification apparatus has a problem that the volume of the color burst signal used for identifying the multi-broadcasting standard is determined analogously, and thus the volume is large and is sensitive to the influences of process variables. Further, the conventional multi-broadcasting standard identification apparatus has a problem that it takes much time to identify the frequency of the color burst signal. That is, the conventional multi-broadcasting standard identification apparatus disclosed in the above-mentioned U.S. patent has a problem that it requires time for displaying a maximum of three frames in order to identify a multi-broadcasting standard.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-broadcasting standard identification apparatus capable of identifying a multi-broadcasting standard of a color television using a frequency of a color burst signal which is determined digitally at a high speed.

According to another aspect of the present invention, there is provided a method for identifying a multi-broadcasting standard performed by the multi-broadcasting standard identifying apparatus.

1 is a schematic block diagram of a multi-broadcasting standard identification apparatus according to the present invention.

FIG. 2 is a flowchart illustrating a method of identifying a multiple broadcast standard according to an embodiment of the present invention performed in the apparatus shown in FIG. 1. Referring to FIG.

3 is a graph for explaining the principle of frequency difference branching.

FIG. 4 is a circuit diagram of a preferred embodiment of the frequency difference calculator shown in FIG. 1 according to the present invention.

FIG. 5 is a block diagram of a preferred embodiment of the identification signal detector shown in FIG. 1 according to the present invention.

According to an aspect of the present invention, there is provided a multi-broadcasting standard identification apparatus for sampling an analog composite video signal having information on a color burst having a frequency of f _C and converting the sampled analog composite video signal into a digital composite video signal, And first and second frequent oscillating signals each having a sine wave form having a frequent oscillation frequency f _a and having a phase difference of 90 ° with respect to each other are multiplied with the sampling value, A low pass filter for performing low pass filtering on the multiplied results and outputting low pass filtered results; and a low pass filter for outputting low pass filtered results between f _c and f _a A frequency difference calculation means for calculating a difference (Z), and means for calculating a difference between Z and the identification signals used to identify the multi- And comparing the levels of the currently compared results with the levels of the previously compared results, and comparing the levels of the previously compared results with each other, identifying and outputting a determination result as said identification signal signal detecting means and a common oscillation means for in response to the identification signal to adjust the f _a, and wherein the first and the output of the second common oscillation signal having the adjusted f _a And the multi-standard is identified according to the logic states of the identification signals.

According to another aspect of the present invention, there is provided a method of identifying a multi-broadcasting standard, comprising: sampling an analog composite video signal having information on a color burst having a frequency f _c and obtaining a digital composite video signal composed of sampled values a) multiplying the sampled values by first and second frequent oscillation signals, each of which has _a frequent oscillation frequency (f _a ) and a phase difference of 90 ° with respect to each other, to obtain multiplied results (c) obtaining low-pass filtered results by low-pass filtering the multiplied results, and obtaining _a difference (Z) between f _c and f _a using the low-pass filtered results; (E) comparing the Z and the reference values, determining whether all of the currently compared results are maintained at the same level for a first predetermined time, If at least one of the results does not maintain the same level for the first predetermined time, proceeding to (b); and if all of the currently compared results remain at the same level for the first predetermined time (G) determining if the levels of the currently compared results are the same as the levels of previously compared results; and if the levels of the currently compared results are not equal to the levels of the previously compared results, (h) adjusting the f _a and the reference values, generating the first and second spontaneous oscillation signals having the adjusted f _a and proceeding to step (b); and Determining whether a second predetermined time has elapsed, if it is equal to the levels of the previously compared results, and proceeding to step (a) if the second predetermined time has not elapsed; and If the second predetermined period of time has elapsed, it is preferably made of a (j) further comprising: corresponding to the above (f) and which are the result of the identification signal determined in step (g) identifying the multiple broadcast standards.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the structure and operation of a multi-broadcasting standard identification apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram of an apparatus for identifying multiple broadcast standards according to the present invention. The apparatus includes an analog / digital converter (ADC) 10, a multiplier 12, a low pass filter (LPF) A frequency difference calculation section 16, an identification signal detection section 18, a frequency tracking section 22 and an oscillation signal generation section 24 constituting the frequent oscillation section 20.

FIG. 2 is a flowchart for explaining a multiple broadcast standard identification method according to the present invention performed in the apparatus shown in FIG. 1, in which the difference between the frequency (f _c ) and the frequent oscillation frequency (f _a ) (Steps 40 to 46), and identifying the multiple broadcasting standard using the frequency difference (steps 48 and 58).

Referring to FIGS. 1 and 2, an analog / digital converter (ADC) 10 includes an analog composite video signal CVBS (Composite), which is expressed as Equation 1 with information on a color burst signal having a frequency f _C Video Baseband Signal) through an input terminal IN1, samples the inputted analog composite video signal CVBS at intervals of a predetermined sampling period T, converts the sampled analog composite video signal CVBS into a digital composite video signal, and outputs sampled values of the converted digital composite video signal And outputs it to the multiplier 12 (Step 40).

Here, Y denotes a luminance signal, A denotes the amplitude of the AC component of the amplitude that is, an analog composite video signal of the color burst signals, ω _c (= 2πf _c) represents an angular velocity.

Here, the frequency f _c of the color burst signal is constant at 4.43 MHz for each line in the PAL system, constant at 3.58 MHz in the NTSC system, and alternately 4.25 MHz and 4.40 MHz for each line in the SECAM system.

After the operation 40, the multiplier 12 multiplies the first and second frequent oscillation signals, which have _a frequent oscillation frequency f _a as a sinusoidal waveform and have a phase difference of 90 ° with respect to each other, (O ₁ and O ₂₎ for the multiplied sampling values and, respectively, the multiplication result (X _k and Y _k) and outputs (where, k is an integer of 1 or more positive) to the LPF (14) (step 42 ).

For example, if the sampled value S _k output from the ADC 10 is Y + And the first and second frequent oscillation signals O ₁ and O _{2 are as} shown in the following Equation 2, the multiplied results X _k and Y _k are expressed by the following Equation 3.

After operation 42, the low-pass filter 14 and the result of (X _k and Y _k) multiplied in the multiplication unit 12, lowpass filtered, the low pass filtered result is expressed as the following equation (4) ( X _k 'and Y _k ') to the frequency difference calculator 16 (operation 44).

After step 44, the frequency difference calculator 16 calculates the difference Z between f _c and f _a using the low-pass filtered results X _k 'and Y _k ' in the low-pass filter 14 , And outputs the calculated difference Z to the identification signal detector 18 (Step 46). if, Is very small, the calculated difference Z is approximated by the following equation (5). In fact, since w _c -w _a is approximately linear at 13.3 °, it can be seen that the above-described assumption can be very usefully applied in an actual situation.

Here, X _{k + 1} 'is a signal output from the low-pass filter 14 following X _k ', and Y _{k + 1} 'is a signal output from the low-pass filter 14 following Y _k '. That is, X _{k + 1} 'is sampled values (S _{k + 1)} and the first common oscillation signal (O ₁₎ for multiplying a value (X _{k + 1)} to indicate the result of low pass filtering, Y _{k + 1'} Pass filtering the value (Y _{k + 1} ) obtained by multiplying the sampling value (S _{k + 1} ) by the second frequent oscillation signal (O ₂ ). At this time, the sampling value (S _{k + 1} ) and the sampling value (S _k ) are adjacent to each other.

Hereinafter, the derivation process of Equation (5) will be described as follows.

3 is a graph for explaining the principle of the frequency difference branch, the horizontal axis _{X k ', X k + 1} ', ... ' represent, and the vertical axis Y _k value (X)', such as, Y _{k + 1} ', ..., respectively.

X _k 'and X _{k + 1} ' and Y _k 'and Y _{k + 1} ', which can be expressed as Equation (6) using Equation (4), are transformed into one circumferential trace ). ≪ / RTI >

Therefore, substituting the expression (6) into the right side of the expression (5) yields the following expression (7).

At this time, In other words, Is very small, Equation (7) is approximated as the following Equation (8).

In the above, the derivation process of Equation (5) is examined. On the other hand, The preferred embodiment of the frequency difference calculation unit 16 shown in FIG. 1 according to the present invention can be implemented as follows.

FIG. 4 is a circuit diagram of a preferred embodiment of the present invention of the frequency difference calculator 16 shown in FIG. 1, in which the first, second, third and fourth delays 60, 62, 64 and 66, Multipliers 68 and 70, a subtractor 72, first and second squarers 74 and 76, an adder 78 and a divider 80.

The first delay unit 60 shown in FIG. 4 delays the low-pass filtered result input through the input terminal IN2 and outputs the delayed result to the second delay unit 62 and the multiplier 70. The second delay 62 again delays the delayed result in the first delay 60 and outputs the delayed result X _k 'to the multiplier 68. Here, the low-pass filtered result _Xk 'and the low-pass filtered result _{Xk + 1} ' are sequentially input from the low-pass filter 14 through the input terminal IN2. Similarly, the third delay 64 delays the low-pass filtered result input through the input IN3 and outputs the delayed result to the fourth delay 66 and multiplier 68. [ The fourth delay 66 delays the delayed result in the third delay 64 and outputs the delayed result Y _k 'to the multiplier 70. Here, the low-pass filtered result _Yk 'and the low-pass filtered result _{Yk + 1} ' are sequentially input from the low-pass filter 14 through the input terminal IN3.

The multiplier 68 multiplies the output _Xk 'of the second delay 62 by the output _{Yk + 1} ' of the third delay 64 and outputs the multiplied result to a subtractor 72 do. The multiplier 70 multiplies the output (X _{k + 1} ') of the first delay unit 60 by the output Y _k ' of the fourth delay unit 66 and outputs the multiplied result to the subtractor 72 do. The subtracter 72 subtracts the output (X _{k + 1} '· Y _k ') of the multiplier 70 from the output (X _k '· Y _{k + 1} ') of the multiplier 68, (80).

On the other hand, the first _multiplier 74 squares the result (X _k ') delayed by the second delay 62 and outputs the result [(X _k ') ² ] to the adder 78. The second _multiplier 76 squares the result (Y _k ') delayed in the fourth delay 66 and outputs the result [(Y _k ') ² ] to the adder 78. At this time, the adder 78 adds the outputs of the first and second squarers 74 and 76 and outputs the added result [(X _k ') ² + (Y _k ') ² ] to the divider 80 . The divider 80 divides the subtracted result in the subtracter 72 into the result added by the adder 78 and outputs the divided result as the difference Z between f _c and f _a to the identification signal detector 18 do.

At this time, if each value of the expression (6) is substituted into the result [( _Xk ') ² + ( _Yk ') ² ] added by the adder 78, . Also, the first and second squarers 74 and 76 may input _{Xk + 1} 'and _{Yk + 1} ', respectively, instead of _Xk 'and _Yk '.

After step 46, the identification signal detector 18 receives the first and second reference values adaptively adjusted in response to the identification signals previously used to identify the broadcast standard, the frequency difference calculator 16, And determines whether each of the compared results is maintained at the same level for a first predetermined time and whether the levels of the currently compared results and the levels of previously compared results are the same, Outputs the discriminated results to the autonomous oscillator 20 as the first and second identification signals, and outputs the results through the output terminal OUT1 (steps 48, 50, and 52).

The preferred embodiments of the identification signal detector 18 according to the present invention and the 48th, 50th, and 52th steps performed in the identification signal detector 18 will be described in detail as follows.

FIG. 5 is a block diagram of a preferred embodiment of the identification signal detector 18 shown in FIG. 1 according to the present invention. The first and second comparators 100 and 102, the first and second discriminators 104 And 106 and a reference value generator 108. [

The first comparator 100 shown in FIG. 5 compares Z with a first reference value output from the reference value generator 108, outputs the comparison result to the first discriminator 104, and the second comparator 102 Compares Z with a second reference value output from the reference value generator 108 and outputs the comparison result to the second determiner 106 (Step 48).

After step 48, the first determination unit 104 determines whether the comparison result in the first comparator 100 maintains the same level for a first predetermined time, and the second determination unit 106 determines whether the comparison result in the second comparator 102) is maintained at the same level for a first predetermined time (Step 50). Here, the reason why Step 50 is performed and the meaning of the first predetermined time will be described as follows. When the composite video signal CVBS input through the input terminal IN1 shown in FIG. 1 does not have a color burst signal, the first and second identification signals output from the identification signal detector 18 through the output terminal OUT1 are multiplexed They can not be valid signals that can be used to identify broadcast specifications. Therefore, as an intermediate process for causing the finally valid first and second identification signals to be generated, step 50 needs to determine whether the composite video signal CVBS has a color burst signal. For this, step 50 uses the point that the comparison result of the first and second reference values and the frequency difference Z does not maintain the same level unless the color burst signal is included in the composite video signal. Therefore, the first predetermined time corresponds to the time when the composite video signal may not include the color burst signal.

At this time, the first predetermined time is set at least larger than the vertical blanking period. The reason why the first predetermined time is set at least larger than the vertical blanking period is as follows.

In general, the vertical blanking period corresponds to the time at which 20 horizontal lines are displayed, and during the period during which 9 horizontal lines are displayed among these vertical blanking periods, the composite video signal CVBS does not have a color burst signal. Therefore, the first predetermined time may be set to the time at which the 9 horizontal lines are displayed in the vertical blanking period, but the first predetermined time may be set to at least vertical Is set to be larger than the blanking period. Also, the composite video signal CVBS may not have a color burst signal even by noise. As a result, when the first predetermined time is experimentally obtained by considering the noise and the vertical blanking period together, the first predetermined period may be set to, for example, the time at which 64 horizontal lines are displayed.

For the 50st step, each of the first and second determiners 104 and 106 may be implemented as a counter. If it is determined that at least one of the first and second determination units 104 and 106 does not maintain the same level during the first predetermined time, the process proceeds to step 42. [

However, if the comparison result is discriminated in both the first and second determination units 104 and 106 that the same level is maintained for the first predetermined time, the first determination unit 104 determines that the first comparator 100 The level of the comparison result is equal to the level of the result previously compared in the first comparator 100, and the second determination unit 106 determines whether the level of the current comparison result in the second comparator 102 is equal to the level of the second comparison It is determined whether or not the level of the previously compared result in the comparator 102 is the same (operation 52). To this end, each of the first and second determining units 104 and 106 includes a buffer (not shown) for storing a previously compared result, and a comparator (not shown) for comparing the currently compared result with a previously compared result, May be provided.

At this time, the first and second determination units 104 and 106 output the first and second identification signals having logical levels corresponding to the results determined in steps 50 and 52, to the oscillation unit 20 , And also through the output terminal OUT1.

If the level of the currently compared result is determined to be not equal to the level of the previously compared result at least in one of the first and second determination units 104 and 106, And outputs the predetermined first and second reference values determined in response to the second identification signals to the first and second comparators 100 and 102, respectively, and the autonomous oscillator 20 outputs the first and second identification signals in response to the adjustment of the f _a, and outputs the first and second common oscillation signal having the adjusted f _a (O ₁ and O ₂₎ to the multiplier 12 (step 54).

To this end, as shown in FIG. 1, the frequency tracking unit 22 of the frequent oscillation unit 20 tracks the frequency of the collar burst signal in response to the first and second identification signals at frequent oscillation frequencies, And outputs the frequency (f _a ) to the oscillation signal generating section (24). The oscillation signal generator 24 outputs the _first and _second oscillation signals O ₁ and O ₂ having the adjusted frequency f _a , which are the tracked frequencies, to the multiplier 12. That is, a frequency tracking unit 22 includes first and second in response to the identification signal, and serves to adjust the f _a, the oscillating signal generator 24 comprises first and second common oscillator having a tuned f _a And outputs signals O ₁ and O ₂ .

If the level of the current comparison result is determined to be the same as the level of the previously compared result, it is determined that both of the first and second determination units 104 and 106 have received the broadcast standard identification (Not shown) determines whether a second predetermined time has elapsed from the initial state of the apparatus shown in FIG. 1 (Step 56). Here, the second predetermined time may be set to twice the first predetermined time. The reason why the second predetermined time can be set to twice the first predetermined time is as follows.

The first and second identification signals output from the identification signal detector 18 shown in FIG. 1 through the output terminal OUT1 are not used only to identify the multiplex broadcasting standard. The frequency of the color burst signal is tracked . That is, the first and second identification signals are used to identify the multiplex broadcasting standard only in a stable state where the frequency tracking of the composite video signal is completed. Thus, for example, the second predetermined time may be set to twice the first predetermined time to ensure that the apparatus shown in Fig. 1 has reached a stable state. At this time, the second predetermined time is not necessarily set to twice the first predetermined time, and may be set to a length of the first predetermined time. If the first predetermined time is set to the time at which 64 horizontal lines are displayed, the second predetermined time is set to the time at which 128 horizontal lines are displayed.

If the second predetermined time has not elapsed, since valid first and second identification signals have not been generated, However, if the second predetermined time has elapsed, the broadcast standard identification unit (not shown) determines that the first and second identification signals generated from the identification signal detection unit 18 through the output terminal OUT1 are valid, And identifies the multiple broadcasting standard corresponding to the logical level of the second identification signals (Step 58). That is, the first and second identification signals generated from the first and second determination units 104 and 106 are not always used to identify the broadcast standard. This is because, in the initial state, the first and second identification signals are used to track the frequency of the color burst signal at a frequent oscillation frequency. Therefore, the broadcast standard identification unit (not shown) identifies the multiple broadcast standard using the valid first and second identification signals output from the identification signal detector 18 after the second predetermined time has elapsed.

For example, (not shown) identifying part broadcasting standard as shown in Table 1 is configured to determine the f _c corresponding to the logic level of the first and second identification signal (I ₁ and I _2), in accordance with the determined f _c Multiple broadcast standards can be identified. At this time, the reference value generator 108 may generate the first and second reference values according to the logic states of the first and second identification signals, as shown in Table 1 below.

In Table 1, L represents a "low" logic level and "H" represents a "high" logic level.

In the initial state, the oscillation unit 20 generates the first and second frequent oscillation signals O ₁ and O ₂ having the frequent oscillation frequency f _a 'and supplies the first and second oscillation signals O ₁ and O ₂ to the multiplier 12, claim 42 to operation 50 is carried out until the conversion to 'f _a and f _c to track the' f in _a frequency tracking unit 22 _a to f. At this time, whether or not the converted f _a 'is accurately tracked to the frequency (f _c ) of the color burst signal is determined for a second predetermined time, and if not, the frequency is again tracked to finally convert f _a ' to f _c .

The frequency (f _a ') oscillated frequently is converted into the frequency of the color burst signal of the composite video signal according to the above-described steps, and the reference value generator 108 shown in FIG. 5 is applied to the first and second identification signals 1 adaptively adjusts the first and second reference values, the apparatus always accurately detects the frequency of the color burst signal irrespective of the frequency (f _c ) of the color burst signal in the initial state can do. This allows multiple broadcast standards to be more accurately identified.

The system clock signal is supplied to each of the units 10, 12, 14, 16, 18, 22, or 24 shown in Fig. This system clock signal can be generated from a timing generator (not shown) in synchronization with the horizontal synchronization signal.

As described above, since the apparatus and method for identifying multiple broadcast standards according to the present invention can digitally identify the frequency of a color burst signal, it is possible to reduce the size of the circuit, It is possible to identify the multiple broadcasting standard.

Claims (7)

An analog / digital conversion means for sampling an analog composite video signal having information on a color burst having a frequency f _C , converting the sampled analog composite video signal into a digital composite video signal, and outputting the sampled values of the converted digital composite video signal; Multiplying means for multiplying first and second frequent oscillation signals, each having _a frequent oscillation frequency (f _a ) and a phase difference of 90 ° with each other, as the sine wave form, and outputting the multiplied results; A low pass filter for low pass filtering the multiplied results and outputting low pass filtered results; Frequency difference calculation means for calculating a difference (Z) between f _c and f _a using the low-pass filtered results; Z is compared with adaptively adjusted reference values in response to identification signals previously used to identify the multiple broadcast standard and whether each of the compared results is maintained at the same level for a first predetermined time, Identification signal detecting means for discriminating whether the levels of the results and the levels of the results compared previously are identical and outputting the discriminated results as the identification signals; And And self-oscillating means for adjusting f _a in response to said identification signals and for outputting said first and said second self-oscillating signals with adjusted f _a , Wherein the multi-standard is identified according to logical states of the identification signals. The apparatus of claim 1, wherein the frequency difference calculation means calculates Z as follows. Wherein A represents the amplitude of the AC component in the analog composite video signal, k represents a positive integer of 1 or more, X _k 'represents the amplitude of the first component of the analog composite video signal, the oscillation signal and the multiplied sampling values value (X _k) represents a result of lowpass filtering, Y _k 'is the second one often multiplying the oscillation signal and the sampled value value (Y _k) low-pass filtered indicates the result, X _{k + 1} 'is the first common oscillation signal and the sampling value and neighboring values (X _{k + 1)} multiplied by the sampled value that represents the result of low pass filtering, Y _{k + 1'} is And a value (Y _{k + 1} ) obtained by multiplying the second frequent oscillation signal by the neighboring sampling value is low-pass filtered. 3. The apparatus according to claim 2, wherein the identification signal detecting means A first comparator to compare Z with one of the reference values and to output a compared result; A second comparator for comparing Z with another one of the reference values and outputting a comparison result; It is determined whether the comparison result in the first comparator maintains the same level for the first predetermined time and whether the level of the current comparison result in the first comparator is the same as the comparison result in the first comparator , First discriminating means for outputting the discriminated result as one of the discrimination signals; It is determined whether the comparison result in the second comparator maintains the same level for the first predetermined time and whether the level of the current comparison result in the second comparator is equal to the level in the second comparison result in the second comparator Second determining means for outputting the discriminated result as another one of the identification signals; And And reference value generation means for generating predetermined reference values in response to the identification signals. 3. The apparatus of claim 2, wherein the self- Frequency tracking means for tracking f _c in response to the identification signals at a frequently oscillated frequency and outputting the tracked frequency; And And oscillation signal generation means for generating the first and second frequent oscillation signals having the adjusted f _a that is the tracked frequency. (a) sampling an analog composite video signal having information on a color burst having a frequency f _c , and obtaining a digital composite video signal composed of sampled values; (b) obtaining multiplied results by multiplying first and second frequent oscillation signals, each having _a frequent oscillation frequency (fa) as a sinusoidal wave form and having a phase difference of 90 degrees with each other, with the sampled values, (c) low pass filtering the multiplied results to obtain low pass filtered results; (d) obtaining _a difference (Z) between f _c and f _a using the low-pass filtered results; (e) comparing the Z with the reference values; (b) if at least one of the currently compared results does not maintain the same level for the first predetermined time period, ; (g) if the current compared results are all at the same level for the first predetermined time, determining whether the levels of the currently compared results are equal to previously compared levels of results; (h) the level of the current comparison result are not the same and the levels of the result compared to the previous, f _a and the first and the second common oscillation signal having the adjusting the reference value, and adjusting f _a And proceeding to step (b); (i) determining whether a second predetermined time has elapsed if the levels of the currently compared results are equal to the levels of the previously compared results, and if the second predetermined time has not elapsed, Proceeding to: (j) if the second predetermined time has elapsed, identifying the multiple broadcasting standard according to the identification signals, which are the results determined in the steps (f) and (g) Identification method. [6] The method of claim 5, wherein step (d) comprises: Wherein, T represents the sampling period, A represents an amplitude of an AC component in the analog composite video signal, k represents a positive integer equal to or greater than 1, and X _k 'represents an amplitude of the first frequent oscillation signal and the sampling value the result (X _k) to represent the result of lowpass filtered multiplying, Y _k 'is the second result of frequent multiplying the oscillation signal and the sampling values (Y _k) to represent the result of low pass filtering, X _{k 1} 'denotes a result obtained by multiplying the first frequent oscillation signal by the sampling value and a sampling value adjacent to the sampling frequency x _{k + 1} , and Y _{k + 1} ' And a result obtained by multiplying the sampling value by an adjacent sampling value and a result (Y _{k + 1} ) obtained by low-pass filtering. 6. The method of claim 5, wherein the first predetermined time is greater than at least the vertical retrace period.