JPH02280467A - Ghost detection circuit and ghost elimination device, and television receiver, tuner and tape recorder using same - Google Patents

Abstract

PURPOSE:To eliminate the need for discriminating which field is being received and to reduce the cost at reception of a GCR signal waveform by dividing fields of a GCR signal at an interval of two fields from a 1st field in the unit of fields, subtracting a signal of an even number field from a signal of an odd number field for each division and adding each difference output mutually after the polarity processing. CONSTITUTION:For example, 8 fields are used as one cycle, bar waveforms f1, f3, f6, f8 are inserted to 1, 3, 6, 8 fields and black level signals f2, f4, f5, f7 are inserted to 2,4,5,7 fields. When the fields of a ghost elimination reference signal(GCR signal) are inserted in this way, difference is obtained sequentially in the GCR signal for an optional odd number field and its succeeding field and the waveform of a difference signal is subject to difference processing. Then a part maximizing the absolute value of the difference waveform before and after the leading part of the bar waveform is sought, the sign of the differential waveform of this portion is obtained and the product between the sign and that of the difference waveform is taken. The obtained waveform is added repetitively for 8 fields to detect ghost. Thus, the capacity of a memory for storing the GCR waveform required to detect the ghost is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ghost detection circuit for a ghost removal device in a television receiver or the like.

[Conventional technology]

In a television receiver, when radio waves arriving directly from the transmitting antenna (desired waves) and radio waves reflected from buildings, etc. (reflected waves) are simultaneously received by the receiving antenna, an image due to the desired waves and the reflected waves are generated. A so-called ghost occurs, where the image appears shifted.

Such ghosts are a major factor in deteriorating the image quality of television receivers, and various methods have been attempted in the past to remove or prevent ghosts. One of them is a ghost removal device using a transversal filter in the video band.

The basic operation of ghost removal by the transversal filter will be explained using FIG. 2 and FIG. 2A.

FIG. 2 is a conceptual diagram of a ghost removal device using a transversal filter, and FIG. 2A is a waveform diagram of signals of various parts thereof.

In FIG. 2, 201 is an input terminal, 202 is a tapped delay line, 203 is a tap amplifier, 204 is an adder, and 20
5 is a subtracter, 206 is an output terminal, and tapped delay line 2
The tap interval is 0.02 and is determined by the highest frequency component contained in the video signal.

When a video signal as shown in FIG. The gain of the tap amplifier 203 connected to the tap (hereinafter referred to as tap gain) is A
shall be. At this time, since the ghost compensation signal shown in FIG. 2A is obtained at the output of the adder 204, the subtracter 204
By subtracting the ghost compensation signal from the signal input in step 5, a ghost-free signal shown in FIG. 2A C can be obtained at the output terminal 206.

There are various algorithms for automatically determining the tap gain, but from the standpoint of stability, IE Transactions on Consumer Electronics, Volume C.E. 26. 1980, 8 May, pp. 629-635 (IEEE, Transac
tion on ConsumerElectroni
cs, Vol, CB-26, AugustL 1
980, p. 629-p. 635) is commonly used. (For a specific example of a ghost removal device, please refer to Japanese Unexamined Patent Publication No. 149523/1983.) FIG. 3 shows a block diagram of an example of the configuration of a ghost removal device using a correlation algorithm.

301 is an input terminal, 302 is an A/D conversion circuit, 303 is a transversal filter, 304 is a differentiation circuit, 305
is a noise reducer, 306 is an output waveform memory, 307
308 is a reference waveform memory, 309 is a subtracter, 310 is a tap gain memory, 311 is a D/A conversion circuit, and 312 is an output terminal.

A video signal input from an input terminal 301 is converted into a digital signal by an A/D conversion circuit 302, ghosts are removed by a transversal filter 303, and then the video signal is converted to a digital signal by an A/D conversion circuit 302.
It is converted into an analog signal by the A conversion circuit 311 and output from the output terminal 312.

The output signal of the transversal filter 303 is differentiated by a differentiating circuit 304, and then noise is suppressed by a noise reducer 305 and stored in an output waveform memory 306.

The arithmetic circuit 307 calculates the data (Y
i) and the data (Ri) previously stored in the reference waveform memory 308, a correlation calculation shown in the following equation is performed.

Zi=α・ΣRk+Yk (1) where α is a positive constant subtracter 309 subtracts the output signal Zi of the arithmetic circuit 307 from the old data Cl0L″ stored in the tap gain memory 310, and tap gain C11llll” (
i indicates the i-th tap amplifier).

Ci ew = Ci Oth - Z i
(2) The new tap gain C1'''' is supplied to the transversal filter 303. By repeating this operation, ghosts are finally removed.

Next, the transversal filter 30 is
The meaning of differentiating the output signal in step 3 will be explained.

In general, ghost detection involves avoiding signal parts that may constantly fluctuate, such as pictures, and picking up signals such as vertical synchronization signals that always appear at regular intervals, and detecting ghost components for the leading edge of this vertical synchronization signal. This is done using the leading edge of the vertical synchronization signal because it is technically easy. (IEE Transactions on Consumer Electronics Volume CEE 24. August 1978, pp. 267-271)
onConsumer Electronic
s, Vol, CE-24° August, 197
B, p, 267-p, 271)) Figure 4a shows the vertical sync signal and its ghost component superimposed thereon (the leading edge of the vertical sync signal and its ghost component); It is assumed that the signal is output from the transversal filter 303 in the figure. Then, in order to detect the delay time τg and amplitude A of the ghost component, the vertical synchronization signal and the ghost component are differentiated by a differentiating circuit 304 to obtain the pulse waveform shown in FIG. If the arithmetic circuit 307 calculates the correlation with a similar pulse waveform that is not marked (Fig. 4C), the correlation value shown in Fig. 4D is obtained, and in the process of calculating the correlation value, the delay time of the ghost is τg is found in the arithmetic circuit 307.

Once the calculation time τg is determined, the transversal filter 3
Since we know which order position in 03 the gain of the tap amplifier should be adjusted, we can slightly modify the gain of that amplifier accordingly. This process is repeated for each incoming vertical synchronization signal to gradually reduce the ghost component and eventually reduce it to zero.

However, the method of detecting ghosts using the leading edge of the vertical synchronization signal has the following problems.

FIG. 5 shows the waveform of the leading edge of the vertical synchronizing signal and its differential waveform when a ghost is added. In the same figure, (A) shows the case where the ghost delay time τg is less than 1/2H (H is l horizontal scanning period), and (B) shows the case where it is more than 1/2H.

In the waveform shown in FIG. 5(A) a, T is the equalization pulse, Tg is its ghost, sy is the leading edge of the vertical synchronization signal,
Syg is the ghost, '3y' is the next vertical synchronization signal,
It is.

In this case, the ghost appears at a location delayed by τg from the leading edge Sy of the vertical synchronization signal, and the ghost can be detected by using the waveform shown in b of (A) obtained by differentiating this waveform. .

On the other hand, in the waveform shown in FIG.
appears, and when this waveform is differentiated, it becomes a waveform containing unnecessary components as shown in the left side of (B), making it impossible to accurately detect ghosts.

As described above, when detecting a ghost using the leading edge of the vertical synchronization signal, there is a problem that if a ghost with a delay time of 1/2H or more exists, the ghost cannot be detected accurately.

Therefore, in order to solve this problem, the Broadcast Technology Development Council is considering having broadcast stations insert a reference signal for ghost removal (hereinafter referred to as a GCR signal) into the vertical retrace period of the video signal and transmit it. ing.

The following two methods are considered as methods for inserting GCR signals.

(B) As shown in Fig. 6, 8 fields are considered as one cycle, and the 1st, 3rd, and 6.8th fields include a bar waveform fl,
[3, f6. [8, 2.4.5° In the 7th field, there is a black level signal f2. f4. Insert f5°fl respectively.

Note that Sy is a horizontal synchronization signal, CB is a color burst signal,
It is.

According to the provisions of the NTSC system, the phase of the color burst signal CB is reversed between the first field day and the second field f2 constituting the first frame; Between the third field f3 and the fourth field f4 constituting the second frame; between the fifth field "5" and the sixth field f6 constituting the third frame; and between the seventh field "7" constituting the fourth frame. The phases of the color burst signals CB are mutually inverted between and the eighth field r8, and the phases of the color burst signals CB are mutually inverted between the corresponding fields between adjacent frames. It will be recognized.

A signal in which one cycle consists of eight fields is a GCR signal.

On the receiver side, the waveform shown in FIG. 6 fl-f8, that is, the GC
The R signal is received and the calculation shown in the following equation is performed on it.

(fl-[5)+(f3-fl)ten(f6-f
2) + (f8-f4) (3) By performing this calculation, the bar waveforms fl, f3f6. The horizontal synchronizing signal sy and its ghost component, the color burst signal CB and its components, and the ghost component of the previous line signal included in waveform f5. f7. f2. f4, and a waveform as shown in FIG. 7a is obtained.

When this waveform is differentiated, it becomes a waveform as shown in the figure, and ghosts up to the delay time τW can be detected.

Therefore, according to the GCR signal insertion method shown in FIG. 6, it is possible to remove the influence of the horizontal synchronization signal, color burst signal, and previous line signal from the waveform transmitted from the broadcasting station, so the delay time Even if there is a ghost whose value is 1/2H or more, it is possible to accurately detect the ghost.

(b) Among the waveforms of the GCR signals shown in FIG. 6 f1 to f8, [1, f3. [5, insert fl between odd fields. Or f2. f4. [6, [8 are inserted only in even fields.

The receiver side receives this and performs the calculation shown in the following equation (4) when inserting into an odd field, and the following equation (5) when inserting into an even field.

(fl-f5)+(f3-fl)
(4) (f6-f2)+ (f8-r4)
(5) The result of the calculation of the above formula (4) or (5),
As in the case of (a), a waveform as shown in FIG. 7 can be obtained.

Therefore, even by inserting only odd fields or only even fields, it is possible to detect ghosts with a delay time of 1/2H or more.

[Problem to be solved by the invention]

The above conventional technology has the following problems.

In order to calculate the above equations (3), (4), or (5), the GCR waveform must be at least 8H's worth in (3)2, and at least 4H's worth in (4)2 or (5). A memo for memorization is required, which increases costs.

Furthermore, it is necessary to determine whether the incoming GCR waveform is from fl to f8 at that time, which is technically complicated.

An object of the present invention is to solve the above-mentioned problems, to reduce the capacity of a GCR signal waveform storage memory required for detecting ghosts, and to make it possible to determine which field is being received when receiving a GCR signal waveform. A ghost detection circuit that does not require discrimination, a ghost removal device, and a television receiver using the same.
The purpose of the present invention is to provide tuners and tape recorders.

[Means to solve the problem]

When the GCR signal is inserted by the method (a) above, the above object of obtaining a ghost detection circuit is achieved by the means shown below.

First, differences are sequentially determined between an arbitrary odd field and the GCR signal of the following field, and the waveforms of the obtained difference signals are differentiated. Next, the bar waveforms rt, r3. re
, Find the part where the absolute value of the difference waveform is maximum before and after the rising part of re, find the sign (polarity is positive or negative) of the difference waveform in this part, and multiply this sign and the difference waveform. Take. By repeatedly adding the waveforms obtained in this manner for eight fields, a waveform as shown in FIG. 7 can be obtained.

When the GCR signal is inserted by the method (b) above, the above object of obtaining a ghost detection circuit is achieved by the means shown below.

Any odd field (or even field) and part 4
After determining the difference between the GCR signals that arrive after the field and subtracting the waveforms of the obtained difference signals, the bar waveforms fl and f3 are
(or f6.f8) (7) Find the portion where the absolute value of the difference waveform is maximum before and after the rising portion, find the sign of the difference waveform in this portion, and multiply this sign with the difference waveform. As a result, a waveform as shown in FIG. 7 can be obtained.

Once a ghost detection circuit is obtained, it is easy to incorporate it into a ghost removal device and to incorporate it into television receivers, tuners, and tape recorders.

(Operation) Ghost detection will be described. First, let us consider the case where a GCR signal is inserted by the method (a) above.

The above equation (3) can be transformed as follows.

(fl-r5)+ ([3-f7)+(f6-f
2) +(r8-f4)=(fl-f2)+
([3-f4)-(f5-f6)-(f718)
(6) Each term in equation (6) above, (fl-f2), (f
3-[4).

(f5-[6), (f7-f8) C. The waveform is as shown in FIG. 8(A). By subtracting each waveform,
The waveform becomes as shown in FIG.

Each waveform A (fl-f2) and Δ(f3-
From f4), A ([5-f6), and A (f71B), detect the part where the absolute value is maximum before and after the rising part of each waveform in (A), and find the sign of that part, sgn( 1,,,2) =+1 sgmouth(3,4)=+1 sgn(5,6) = −1 sgn(7,8) ”” l (7
) Here, sgn(i, j) is A(fi-f
The sign obtained from j) is shown.

becomes.

Therefore, the above equation (6) is (ft-12)・+ (r3- r,i )-(f5-
f6 )-(f7-f8) where n=2 i-1,
It is expressed as m=2i. Furthermore, the difference of the above equation (8) is A (([1-f2)+(f3-f4)(
It is expressed as f5-f6)-(f7-r8)+. The difference between the above equation (8), ie, equation (9), is nothing but the waveform shown in FIG.

The calculation of the above equation (9) can be realized by repeating the process four times using only the GCR signal of the odd field and the GCR signal of the subsequent field. Further, since the order of each term in the above equation (9) is interchangeable, exactly the same result can be obtained even if processing starts from any odd field.

Therefore, start processing from any odd field,
Since it is sufficient to process the two fields in the order in which they arrive,
It may be necessary to memorize all waveforms f1 to f8 (but it is possible to obtain the waveform shown in FIG. 7).

Furthermore, since the calculation of equation (9) above can be realized if it is possible to determine whether the field is an odd field or not, it is not necessary to determine which field is the current field when receiving the GCR signal waveform.

Next, consider the case where the GCR signal is inserted using the method (b) above.

If processing starts from fl, [3 (or [6, f8)],
These fields and the G that arrives after 4 fields
CR signal difference (fl-f5), (f3-f7), (f
6-f2) and (f8-[4), the waveform shown in FIG. 7 is immediately obtained.

Therefore, consider a case where processing starts from [5, f7 (or f2.f4).

Each term in the above equation (4) or (5) can be modified as follows.

(fl-f5)=-(f5-fl)
(10)(f3-f7)=-(f7-f3)
(11) Cf6- f2 ) =-(f2-
[6) (12) (f8- f4) =
-(f4- f, 8) (13) Above (1)
0) 2~Right side of equation (13), (f5-[1), (f
7-[3), (f2-f6), (f4-[8)
is a waveform that is an inversion of the waveform shown in FIG. 7a.

Therefore, by subtracting each waveform, the waveforms fl, [3°f6 .
When detecting the portion where the absolute value is maximum before and after the rising portion of f8 and finding the sign of that portion, the signs are both negative.

Therefore, the above formulas (lO)2 to (13) are -(f5
-fl)=sgn(5,1)・(f5-[1) (
14)-(f7-f3)=sgn(7,3)・(f7-
f3) (15)-(f2-f6)=sgn(2,
6), ([2-f6) (16)-(f4-f8)
=sgn(4,8).(f4-f8) (17) By multiplying the difference waveform and its sign, the waveform shown in FIG. 7 can be obtained.

If processing starts from fl, f3 (or [6, [8)],
Since sgn(n, m)=+l always holds, the above (4
)2 or (5) Multiply each term of 2 with sgn(n, m), and get (fl-[5)=sgn(1,5)・(fl f5)
(1B) (f3-f7)-sgn(3
,7)・(f3−f7) (19)(f
6-f2)=sgn(6,2)・(f6-f
2) (20)(f8-f4)=s
gn(8,4)・(f 8 f 4 ) <2
1), the results are exactly the same.

Therefore, starting processing from any odd field (or even field), the GC that arrives after 4 fields
If processing is performed with the R signal, the waveform shown in FIG. 7 can be obtained, so the waveform [1°f3. f5. It is not necessary to store all f7 (or f2.f4.[6, f8).

In addition, the above equations (14), (15) and (18),
(19) (or (16), (17) and (2)
The calculations of equations (0) and (21) can also be realized if it is possible to determine whether the field is an odd field or not, so there is no need to determine which field of the GCR waveform is being received.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a ghost detection circuit according to the present invention, and blocks with the same numbers as those in FIG. 3 have the same functions. 101
is a ghost detection circuit, 102 is an input terminal, and 103 is a GC.
An R signal processing circuit, 104 is an arithmetic circuit, and 105 is an output terminal.

The GCR signal processing circuit 103 performs the calculation shown in equation (9) above on the GCR signal supplied from the input terminal 102. The output signal of the GCR signal processing circuit 103 is stored in the output waveform memory 306 via the noise reducer 305. The arithmetic circuit 104 performs a correlation operation between the waveform stored in the output waveform memory 306 and the contents of the reference waveform memory 308, and outputs the result to the output terminal 105.

An example of the configuration of the GCR signal processing circuit 103 is shown in FIG.

In the figure, 901 is an input terminal, 902 is a waveform memory, 903 is a first memory circuit, 904 is a subtracter, 905
is a differential circuit, 906 is a maximum value and sign detection circuit, 907
is a sign register, 908 is a multiplier, 909 is an adder, 9
10 is a second memory circuit, and 911 is an output terminal.

The GCR signal processing circuit 103 in the same figure is a circuit that performs the processing of the above equation (9), and corresponds to the case where the GCR signal is sent by the method shown in the above (a).

The odd field GCR signal taken into the waveform memory 902 from the input terminal 901 (Fig. 6 [1°f3.[5,
[7] is transferred to the first memory circuit 903. Here, the waveform memory 902 must be operable at the sampling frequency of the input GCR signal. However, the transfer from the waveform memory 902 to the first memory circuit 903 only needs to be completed during the period until the next GCR signal arrives at the waveform memory 902 (ie, the 1 field period). Therefore, the first memory circuit 903 does not need to operate at high speed.

The subtracter 904 subtracts the even field GCR signal (f2.f4.f6° f8 in FIG. 6) newly taken into the waveform memory 902 from the odd field GCR signal stored in the first memory circuit 903. The output thereof is subjected to a difference in a difference circuit 905. The maximum value and sign detection circuit 906 determines the sign (positive or negative polarity) at the point where the absolute value of the output signal of the difference circuit 905 is maximum, and stores the result in the sign register 907. In the multiplier 90B,
The output signal of the difference circuit 905 is multiplied by the sign (positive or negative polarity) that is the content of the sign register 907, and then the adder 909
(Note that during multiplication in multiplier 908, the result of multiplying a positive sign by a positive sign is positive, but the result of multiplying a negative sign by a negative sign is also positive). The adder 909 adds the waveform previously stored in the second memory circuit 910 and the output of the multiplier 908, and stores the result in the second memory circuit 910 again.

By repeating this series of operations over eight fields, the waveform shown in FIG. 7 is output from the output terminal 911.

FIG. 10 shows a GCR signal processing circuit 103 corresponding to the case where the GCR signal is sent by the method shown in (b) above.
An example of the configuration is shown below. In this figure, blocks with the same numbers as those in FIG. 9 are blocks with the same functions. 1001 and 1006 are switches, 1002 is the first
1003 is a first subtracter, 1004 is a second memory circuit, and 1005 is a second subtracter.

Below, we will discuss the case where a GCR signal (fl, f3. [5, [7) in FIG. Explain the operation.

The two switches 1001 and 1006 are interlocked and switch to the a side or the b side in frame cycles. Among the GCR signals taken into the waveform memory 902 from the input terminal 901,
The first one (assumed to be fl) is transferred to the a side by the switch 1001, that is, to the first memory circuit 1002, and the next one (f3) is transferred to the b side by the switch 1001. That is, it is transferred to the second memory circuit 1004. The third arriving GCR signal (f5) is supplied to the a side by the switch 1001,
In the first subtracter 1003, the GC that arrived two frames ago and was stored in the first memory circuit 1002 in advance
is subtracted from the R signal (i.e. fl) and the result (rl-4
5) is supplied to the differential circuit 905 via the switch 1006.

The fourth arriving GCR signal (fl) is sent to the switch 100.
1 to the b side, and in the second subtracter 1005, r which was previously stored in the second memory circuit 1004
3 and the result (f3-rl) is the switch 10
06 and is supplied to the differential circuit 9O5.

The output of switch 1006 is differentiated in difference circuit 905. The maximum value and sign detection circuit 906 detects the sign (
polarity) and stores the result in sign register 907.

The multiplier 908 multiplies the output signal of the difference circuit 905 by the sign (polarity) that is the content of the sign register 907 and supplies the result to the output terminal 911 .

Through this series of operations, the above equations (18) and (19) are calculated, and the waveform shown in FIG. 7 is output from the output terminal 911. The GCR signal that arrived first was [3,
[If it is either 5 or fl, the above (1
9) and (14), (14) and (15), (
The calculations of equations (15) and (18) are performed, and the waveform shown in FIG. 7 is similarly output from the output terminal 911.

The GCR signal processing circuit 103 in the same figure processes the GCR signal (f2 [4, [6, f
8 is inserted and sent, the same operation occurs, and one of the above equations (16), (17), (20), and (21) is performed. , the waveform shown in FIG. 7 can be obtained from the output terminal 911.

FIG. 11 is a block diagram showing another embodiment of the ghost detection circuit according to the present invention.

In this figure, blocks with the same numbers as those in FIG. 1 or 3 have the same functions. 11
01 is a ghost detection circuit, 1102 is a GCR signal multiplication circuit 103 is an arithmetic circuit, and 1104 is a malfunction detection circuit.

A ghost detection circuit 1101 in the same figure is a part of the GCR signal processing circuit 1 in the ghost detection circuit 101 shown in FIG.
A new function is provided to detect a malfunction of the arithmetic circuit 104 and to stop the operation of the arithmetic circuit 104 if a malfunction occurs. The signal received by the GCR signal processing circuit 1102 is
If a malfunction occurs due to reasons such as the R signal not being inserted, the malfunction detection circuit 1104 detects the GCR signal processing circuit 11.
This is detected from the code information supplied from 02, and a control signal is sent to the arithmetic circuit 1103 to stop the operation of the arithmetic circuit 1103.

FIG. 12 shows the GCR signal processing circuit 11 in FIG.
02-Show a configuration example. In this figure, blocks with the same numbers as those in FIG. 9 have the same functions. 1201 is a code output terminal. Also, G in the same figure
The CR signal processing circuit 1102 processes the GCR signal as described above (a).
It corresponds to cases where it is sent by the method shown in .

A GCR signal processing circuit 1102 shown in FIG. 12 has a configuration in which a code output terminal 1201 is newly added to the GCR signal processing circuit 103 shown in FIG.

Hereinafter, a method of detecting a malfunction by the malfunction detection circuit 1104 will be explained using FIG. 11 and FIG. 12.

The code register 907 outputs the code shown in equation (7) above. Therefore, the first arriving GCR signals are fl, f3 . f5. f7, the code strings output from the code register 907 are (+, +, −, −), respectively.

(+　　--,+).

(−, −, +, +).

(-, +, +, -), (
23). Therefore, the malfunction detection circuit 1104 receives the code string output from the code register 907 from the code output terminal 1201, and sends the code string from the code output terminal 1201 to the above (
23) If a code string other than that shown in the formula is output, G
It is assumed that the CR signal processing circuit 1102 has malfunctioned and a control signal is generated.

An example of the malfunction detection circuit 1104 is shown in FIG.

In the same figure, 1301 is an input terminal, 1302 130
3 is a flip-flop, 1304 is an exclusive OR operator, and 1305 is an output terminal.

The code string input to the input terminal 1301 is delayed by flip-flops 1302 and 1303. The exclusive OR operator 1304 performs an exclusive OR operation on the newly input code and the code delayed by the flip-flops 1302 and 1303, and sends the result to the output terminal 13o5.
Output to.

In each of the above equations (23), the first and third,
Or, if you compare the second and fourth codes, the two codes will never lose. Therefore, the exclusive OR operator 130
In step 4, if the newly input code is exclusive-ORed with the code that arrived two times before, the result will always be l.

Therefore, the output of the IF passive OR operator 1304 is 0.
If this occurs, it is determined that the GCR signal processing circuit 11o2 has malfunctioned, and a control signal for stopping the operation of the arithmetic circuit 1103 in FIG. 11 is output to the output terminal 1305.

In the ghost detection circuit 1101 of FIG. 11, it is possible to determine whether or not the detection of the GCR signal has been performed normally, so that malfunctions can be prevented.

In the ghost detection circuit according to the present invention described above, processing such as addition, subtraction, 1 multiplication, difference, maximum value detection, and sign determination are all performed using dedicated hardware, but these processings are performed using a CPU. There is no problem at all if you go.

Further, although the tap gain Ci is corrected according to the above equation (2), it is also possible to correct the tap gain Ci according to the following equation using only the output signal Yi.

(Zero forcing method) C1i・ga=Ci”' −Yi (24)
Next, an application example of the ghost detection circuit according to the present invention will be described.

FIG. 14 shows an embodiment of a ghost removal device including a ghost detection circuit 101 according to the present invention.

In this figure, blocks with the same numbers as those in FIG. 3 have the same functions.

The ghost detection circuit 101 detects a ghost from the output signal of the transversal filter 303, and
The correction amount Zi of the tap gain Ci is output to.

FIG. 15 shows a ghost removal device 1401 shown in FIG.
1 shows an embodiment of a television receiver equipped with the following. In the figure, 2001 is an RF input terminal, 2002 is a tuner, 2003 is an IF detection circuit, 2004 is a luminance signal/chrominance signal separation circuit (hereinafter abbreviated as Y/C separation circuit), 2005
2006 is a color demodulation circuit, 2006 is a color synchronization circuit, 2007 is a matrix circuit, and 2008 is a display device.

After the RF multiplied signal inputted from the RF input terminal 2001 is tuned and detected by the tuner 2002 and the IF detection circuit 2003, the ghost is removed by the ghost removal device 1401. The output signal of the ghost removal device 1401 is Y
/C separation circuit 2004, color demodulation circuit 2005, color synchronization circuit 2006, and matrix circuit 2007 convert the signals into RGB signals, which are then supplied to display device 2008.

FIG. 15 shows an example of application as a television receiver, but the RF input terminal 2001, tuner 200
2. IF detection circuit 2003 and ghost removal device 140
It can also be applied to a television tuner consisting of 1.

FIG. 16 shows a ghost removal device 1401 shown in FIG. 14.
An example of a VTR equipped with the following is shown. In the same figure, the first
Blocks with the same numbers as those in Figure 5 indicate the same functional blocks, 2011 is a video signal recording circuit, 2
012 is a video head, 2013 is a video signal reproducing circuit, and 2014 is a video output terminal.

The RF multiplied signal inputted from the RF input terminal 2001 is converted by the tuner 2002, the IF detection circuit 2003, and the ghost removal device 1401 into a video signal from which ghosts have been removed. This video signal is stored in a video signal recording circuit 20.
11. Recorded on a magnetic tape (not shown) by a video head 2012. The video signal reproduction circuit 2013 is
The video head 2012 converts the signal read from the magnetic tape into a video signal, and the video output terminal 2014 converts the signal read from the magnetic tape into a video signal.
supply to.

In the embodiment of FIG. 16, the input signal is sent to the RF input terminal 200.
1, but it will be explained that the same effect can be obtained even if a signal that has been converted into a video signal by an external television tuner or the like is directly input to the ghost removal device 1401. Not even.

[Effects of the Invention] According to the present invention, when a GCR signal is transmitted in the format of 8 fields per cycle as shown in FIG.
By using a GCR waveform memory with a capacity of can. Furthermore, according to the present invention, processing of the GCR signal for ghost detection can be started from any odd field (or even field) within the blanking period.
As long as it is possible to determine whether it is an odd field or not, the calculations shown in the above equations (3), (4), or (5) can be performed.
Since a ghost can be detected without determining whether the incoming GCR signal is one of f1 to f8 in FIG. 6 at that time, there is an advantage that the circuit configuration is simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a ghost detection circuit according to the present invention, FIG. 2 is a block diagram showing the basic operation of a transversal filter, FIG. 2A is a waveform diagram of each part of the transversal filter, and FIG. 3 is a transversal filter A block diagram showing a conventional example of a ghost removal device using a filter; FIG. 4 is a waveform diagram showing a ghost detection method using the leading edge of a vertical synchronization signal;
Figure 5 is a waveform diagram showing the detection situation when detecting a ghost using the leading edge of the vertical synchronization signal, Figure 6 is a waveform diagram showing how to insert the GCR signal with 8 fields as one cycle, and Figure 7 is Figure 6 is a waveform diagram showing the waveform obtained by calculation processing of the waveform in Figure 6. Figure 8 is a waveform diagram showing the waveform generated in the process of calculation processing of the waveform in Figure 6. Figure 9 is the GCR signal processing in Figure 1. Block diagram showing an example of a circuit configuration, 1st
0 is a block diagram showing another example of the configuration of the GCR signal processing circuit in FIG. 1, FIG. 11 is a block diagram showing another embodiment of the ghost detection circuit according to the present invention, and FIG.
1 is a block diagram showing an example of the configuration of the GCR signal processing circuit in FIG. 1, FIG. 13 is a block diagram showing a specific example of the malfunction detection circuit in FIG. 12, and FIG. FIG. 15 is a block diagram showing an embodiment of the ghost removal device shown in FIG. 14, and FIG. 16 is a block diagram showing an embodiment of the television receiver equipped with the ghost removal device shown in FIG. 14. 1 is a block diagram showing an embodiment of a video tape recorder equipped with a ghost removal device. FIG. Explanation of symbols 101.1101...Ghost detection circuit, 103°1
102...GCR signal processing circuit, 104,307°1
103... Arithmetic circuit, 305... Noise reducer, 306... Output waveform memory, 30B... Reference waveform memory, 902... Waveform memory, 903, 910, 1
002.1004...Memory circuit, 904,1003
゜1005...Subtractor, 905...Difference circuit, 90
6... Maximum value and sign detection circuit, 907... Sign register, 908... Multiplier, 909... Adder, 1
001.1006...Switch, 1104...Malfunction detection circuit agent Patent attorney Akira Namiki Futoshi 1 Prisoner! a2 Figure 2A @3 Figure 5! ! 1 11E4 figure ○ τ9 w 6 Figure abuse 99 (A,) CB) @8 Figure @10 figure-42'; @12 figure

Claims (1)

[Claims] The 1st and 3rd field periods are defined as one cycle.
, the 6th and 8th fields carry a bar waveform, and the remaining 2nd, 4th, 5th, and 7th fields carry a black level signal. Between the second field, the phases of the color burst signals included therein are inverted, and similarly between the third and fourth fields that make up the second frame, and the fifth and sixth fields that make up the third frame. The phase of the color burst signal is inverted between the 7th and 8th fields constituting the 4th frame, and the phase of the color burst signal is also reversed between the corresponding fields when viewed between each frame. A reference signal for ghost removal (hereinafter referred to as a GCR signal) in which In a ghost detection circuit that detects a ghost component included in a video signal by processing a GCR signal, the first and second, third and fourth, 5th, 6th, 7th
and eighth, a subtraction circuit that subtracts the even field signal from the odd field signal for each division, a difference circuit that calculates the difference between the difference signals obtained by subtraction, and each difference output. It includes a GCR signal processing circuit consisting of a polarity processing circuit that processes the polarities so that they become the same when the polarities are different, and an addition circuit that mutually adds the difference outputs after polarity processing, and uses the processing results. A ghost detection circuit characterized in that the ghost component is detected by detecting the ghost component. 2nd and 8th field periods are considered as one cycle, and
, the 6th and 8th fields carry a bar waveform, and the remaining 2nd, 4th, 5th, and 7th fields carry a black level signal. Between the second field, the phases of the color burst signals included therein are inverted, and similarly between the third and fourth fields that make up the second frame, and the fifth and sixth fields that make up the third frame. The phase of the color burst signal is inverted between the 7th and 8th fields constituting the 4th frame, and the phase of the color burst signal is also reversed between the corresponding fields when viewed between each frame. A reference signal for ghost removal (hereinafter referred to as a GCR signal) in which the field and receive it, or insert only the second, fourth, sixth, and eighth fields into even fields of the vertical retrace period of the video signal and receive it. In a ghost detection circuit that detects a ghost component included in the video signal by receiving the received GCR signal and processing the received GCR signal, an arbitrary field of the received GCR signal and a field 4 fields after the received GCR signal are detected. a subtraction circuit that subtracts signals between the two, a difference circuit that calculates the difference between the difference signals obtained by subtraction, and a polarity processing circuit that processes the difference outputs so that they have the same polarity when the polarities are different. A GC consisting of an adder circuit that mutually adds each difference output after polarity processing.
A ghost detection circuit comprising an R signal processing circuit and detecting the ghost component using the processing result. 3. The ghost detection circuit according to claim 1 or 2, wherein the polarity processing circuit includes a polarity detection circuit that detects the polarity of the differential output from the difference circuit, and a polarity holding circuit that holds the detected polarity. A ghost detection circuit comprising: a multiplication circuit that multiplies the held polarity and the difference output from the difference circuit and outputs the result to the addition circuit. 4. The ghost detection circuit according to claim 1 or 2, further comprising a malfunction detection circuit that stops the ghost component detection operation when a malfunction of the GCR signal processing circuit is detected. 5. The ghost detection circuit according to claim 4, wherein the malfunction detection circuit includes a delay circuit that delays the polarity signal output from the polarity holding circuit by two times, and a delay circuit that delays the polarity signal output from the polarity holding circuit and the delay. A ghost detection circuit comprising: an exclusive OR circuit that performs an exclusive OR with a polarity signal from the circuit and outputs the result. 6. A transversal filter receiving a video signal whose ghost components are to be removed; and a transversal filter receiving an output signal of the transversal filter to detect ghost components therein. 6. A ghost removal device comprising: the ghost detection circuit according to . 7. A channel selection circuit that receives television RF signals and selects a channel, and an IF that converts the output signal of the channel selection circuit into a video signal.
7. A television receiver comprising a detection circuit, a conversion circuit for converting an output signal of the IF detection circuit into an RGB three primary color signal, and a display device for displaying the RGB three primary color signal, after the IF detection circuit. A television receiver comprising the ghost removal device described above. 8. In a television tuner comprising a channel selection circuit that receives a television RF signal and selects a channel, and an IF detection circuit that converts the output signal of the channel selection circuit into a video signal, the following claim is provided after the IF detection circuit. 7. A television tuner comprising the ghost removal device according to 7. 9. A video signal recording circuit that converts an input video signal into a signal to be recorded on a magnetic recording medium and outputs the signal, and a video head that records and reproduces the output signal of the video signal recording circuit on the magnetic recording medium; A video tape recorder comprising a video signal reproducing circuit that converts a reproduced signal from the video head into a video signal, characterized in that the ghost removing device according to claim 7 is provided before the video signal recording circuit. video tape recorder.