JPH03289271A - Ghost elimination circuit - Google Patents

Abstract

PURPOSE:To accurately eliminate ghost by applying high frequency noise elimination processing to a reception ghost elimination reference signal calculating each ghost elimination filter coefficient for an acyclic filter and a cyclic filter. CONSTITUTION:The circuit is provided with a 1st setting means setting a 1st coefficient group to an acyclic (FIR) filter 10 synchronously with a timing when a reception ghost elimination reference signal appears at an input video signal, an arithmetic means calculating respectively a 2nd filter coefficient group for ghost elimination to the FIR filter 10 and a 3rd filter coefficient group for ghost elimination to the cyclic (IIR) filter 20 based on a ghost elimination reference signal in the 1st and 2nd memories, and a 2nd setting means setting the 1st and 3rd filter coefficient groups to the FIR filter 10 and the IIR filter 20. Then the filter coefficient for low pass filter is set to fetch a reception GCR signal whose high frequency noise component is eliminated into a memory M. Thus, ghost component in the video signal is accurately eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ghost removal circuit for removing ghost disturbances in a television system, and more specifically, to a ghost removal circuit for removing ghost disturbances in a television system. This invention relates to a ghost removal circuit.

[Conventional technology]

A circuit has been proposed that uses a ghost removal reference signal (hereinafter referred to as a GCR signal) having a rising waveform of sin X/X to remove the ghost component from a received television signal to obtain high image quality. ing.

This type of ghost removal circuit generally consists of a cascade connection of an FIR filter (non-recursive filter), which mainly removes nearby ghosts, and an IIR filter (recursive filter), which mainly removes normal ghosts. That's what happens.

Conventionally, in a ghost removal circuit with such a configuration,
Part of the received GCR signal is stored in a memory, and this stored received GCR signal and the GCR signal stored in advance in the circuit are combined.
FIR is executed by a microprocessor etc. based on the CR signal.
The filter coefficients (so-called filter tap coefficients) of the filter and the JIR filter are calculated and set in these filters, and then the received video signal is passed through these filters to remove its ghost components. That's what I do. In this case, if high frequency noise is mixed in the received GCR signal stored in the waveform acquisition memory, the FIR calculated using this received GCR signal
The filter coefficients for the filter and the IIR filter are also inaccurate, resulting in a problem in that the ghost component cannot be accurately removed from the received video signal.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a ghost removal circuit that can more accurately remove ghost components in a video signal in a ghost removal circuit configured by cascading a FLL filter and an IIR filter. be.

[Means for Solving the Problems and Their Effects] A ghost removal circuit according to the present invention is formed by cascading an acyclic filter and a cyclic filter, and is provided on the output side of the acyclic filter. , a first memory for storing a received ghost removal reference signal in an input video signal that has passed through the acyclic filter; a second memory in which a predetermined ghost removal reference signal is stored in advance; a third memory pre-stored with a first filter coefficient group for imparting a low-pass filter characteristic substantially corresponding to the frequency characteristic of the ghost removal reference signal to the filter; and a third memory storing the received ghost removal reference signal on the input video signal. a first setting means for setting the first filter coefficient group in the acyclic filter in synchronization with the timing at which the signal appears; a calculation means for calculating a second filter coefficient group for ghost removal for the acyclic filter and a third filter coefficient group for ghost removal for the cyclic filter based on the removal reference signal; The present invention is characterized in that a second setting means is provided for setting the second filter coefficient group and the third filter coefficient group to the acyclic filter and the recursive filter, respectively.

According to the above configuration, the received ghost removal reference signal used to calculate each ghost removal filter coefficient for the acyclic filter and the recursive filter has been subjected to high frequency noise removal processing. More accurate ghost removal can be achieved, and there is no need to provide a special filter to remove high frequency noise.

〔Example〕

First, before explaining the embodiments of the ghost removal circuit according to the present invention, the principle of operation of the present invention will be explained.

FIG. 1 shows F in the ghost removal circuit according to the present invention.
It shows a cascade connection relationship between an IR filter and an IIR filter, and the connection configuration of such two filters itself is known. In this case, the FAR filter 10 is a transversal filter (TF) 11, while the IIR filter 20 has a transversal filter (TF) 2 in the return path.
1, so that the output of the FIR filter 10 is input to the adder 22. Further, on the output side of the FIR filter 10, a memory M having a storage capacity sufficient to store, for example, at least one line of video information is provided.

In the above configuration, first, when the waveform of the GCR signal (received GCR signal) that has suffered a ghost disturbance in the input video signal is taken into the memory M, the FIR filter 10 is
Set filter coefficients for a low-pass filter that has a frequency characteristic that almost corresponds to the frequency characteristic of the 5inx/x signal in the R signal (actually has a cutoff frequency around 4.2 MHz).In this way, the memory M The received GCR signal from which high frequency noise components have been removed is taken in. Next, the received GCR signal in the memory M is differentiated and the 5 inch
The x/x signal is extracted, and based on this 5inx/x signal and the reference 5inx/x signal stored in advance in the circuit, ghost removal filter coefficients (hereinafter referred to as FIR filter coefficients) for the LIR filter IO are determined. IIR filter 12
Ghost removal filter coefficients (hereinafter referred to as IIR filter coefficients) are calculated using a method similar to the conventional method. That is, the FI is calculated using the least squares method based on the time series information ×(k) of the sin X/X signal extracted from the received GCR signal and the time series information r(k) of the reference sin X/X signal.
Calculate R filter coefficients and IIR filter coefficients,
Alternatively, FIR filter coefficients and IIR filter coefficients are calculated from the frequency characteristics of these signals using a fast Fourier transform (FFT) algorithm. These calculated FIR filter coefficients and IIR filter coefficients are set in the transversal filter 11 in the FIR filter 10 and the transversal filter 21 in the IIR filter 20, respectively.

Further, the above-mentioned FIR filter coefficient and IIR filter coefficient may be set as follows. That is, the FIR filter coefficient is determined by the known method described above, the output signal y(k) for the signal x(k) from the FIR filter 10 set with this FIR filter coefficient is determined, and this y
The time series information (k) is not subjected to any special calculations, that is, each part of this time series data is set as a filter coefficient in the IIR filter 20 with a corresponding time relationship.

The reason why the cost obstacle can be removed by setting the output signal y (k) of the FIR filter 10 as the coefficient of the IIR filter 20 in this way will be explained below.

First, to simplify the explanation, ghost removal is performed on a sinusoid that has suffered a coast disturbance, for example, the waveform shown in FIG.
It is assumed that the filter operation is to reproduce a reference sin X/X signal r (k) whose waveform is shown in FIG. 3(a) from an X/X signal x (k). Note that the above signal r(k
As shown in Figure 3(b), the frequency characteristic R(w) of ) is flat from direct current to a frequency wc of 4.2 MHz, and rapidly attenuates to zero at frequencies higher than that. .

As shown in FIG. 2, the signal x(k) includes a front ghost on the upstream side of the reference point ○ of the signal, and a delayed ghost on the downstream side thereof. Then, each filter coefficient h (k) of the FIR filter 10 is calculated from this signal x (k)
The F of the signal x(k) in this region is affected by the region including the front ghost of
The signal y(k) after passing through the IR filter 10 is y(k) −r(k) (P≦k≦Q)
−(1).

In this case, the output y (k) of l'lR filter 0 is
becomes. Furthermore, from the above equation (1), the FIR filter coefficients need to have the following relationship.

[R co-[)1] [X'J
... (3) Here, [R] = [r(P) r(P+1)-r(Q
)] [H co -[h (P) h (P+1) -
...h ((]) ](k). Therefore, the signal y(k> is y(k) - x''(k) + r(k) + x' (
k) −(5) or. Therefore, the FIR filter coefficient h (k) is [
Old = [Rco[X]-'
... It can be obtained by calculating (4). Here, [X]-' is the inverse matrix of [X].

However, since calculation of the inverse matrix of [X] is very complicated, the FIR filter coefficients are usually determined by an adaptive method such as the mean square error method or an algorithm using FFT, as described above.

In this way, after calculating the FIR filter coefficient h (k) and setting these coefficients in the FIR filter 10, the sin Pass through filter IO. In this case, the output signal y (
The portion corresponding to the region P-Q of k) can be expressed as a reference signal r, and its waveform is shown in FIG. Here, the signal X''(k) represents the residual ghost in the region upstream from point P, and the signal x'(k) represents the residual ghost in the region downstream from point Q.

Then, the inverted signal -x' (k) of the above signal x' (k)
) is set as a filter coefficient in the IIR filter 20 in a corresponding time relationship. As a result,
Since the portion of the signal y(k) in FIG. 4 corresponding to the signal x' (k) is canceled out, the output signal jo(k) of the IIR filter 2o has a waveform as shown in FIG. o(k
) = r(k)...(6)
becomes.

The ghost removal operation described above can be proven as follows.

The output Y (w) of the FIR filter 10 is expressed as -X' (w
), the output 0 (w) of this filter 20 is 0
(w) = Y(w>−X' (w)0(w)
−(7). Therefore, wc is the frequency at which R(w) starts to decrease from 1.

Therefore, the frequency portion OL (W) lower than the frequency wc (w<wc) at the output 0 (w) is...(8
) It can be expressed as. Here, as mentioned earlier,
The filter coefficient of the R filter 10 is the front ghost area 〇-
Since it is set to cover up to P, X''(w) in the above equation (8) is negligible compared to R(w). Therefore, the above equation (8) can be expressed as .Here, as shown in Fig. 3(b), the frequency characteristic R(w) is 1 within the frequency band, so it can be expressed by dividing it into two regions as follows. .

1 + X'L(w) 1,000 X't(w) 1 = RL (w) -
(11). Thus, the frequency portion below the frequency wc at 0(w) is equally flat as the low frequency portion of R(w).

Also, higher than the frequency wc at output 0(w), )(w
e≦W) Frequency part 0. I(w) is RH(w)
10 X' [I (w). Here, X'g(
iv) is X'(iv), that is, the residual ghost signal x' (
This is the high frequency part of the frequency characteristic of k). This (1
2) Formula shows that the smaller X' a (w), the more DH(w)
indicates that it approaches tta (w).

Therefore, unless the received video signal contains a very large coast, OlI(w) can be considered substantially the same as Rg(w).

According to the setting method of each filter coefficient as described above, the low frequency part of the output 0(w) of the ghost removal circuit is the same as the low frequency part of R(w), and 0(w) The high frequency part of R(w) is also very close to the high frequency part of R(w).

Embodiment Using Ordinary CPU Next, an embodiment of the ghost removal circuit according to the present invention constructed using an ordinary microprocessor will be described with reference to FIG.

In FIG. 6, F
The IR filter 10 and the IIR filter 20 have the same configuration as that shown in FIG. A switch 31 is provided between the input terminal of the transversal filter 11 constituting the PIR filter 10 and the signal input terminal 30 of the ghost removal circuit, and this input terminal 30 receives signals sampled at a predetermined sampling frequency. At the same time, digitized received video signals are sequentially supplied. The switch 31 is configured, for example, as a multiplexer, and under the control of a microprocessor 32 (to be described later), outputs either the video signal from the input terminal 30 or the output of a buffer memory 33 having a storage capacity of one line of video signals. P.I.
It is supplied to the input end of the R filter 10. Further, the output of the transversal filter 11 is supplied to the adder 22 in the IIR filter 20, and is also supplied to a waveform acquisition memory 34 having a storage capacity of at least one line of video signal.
It is also being supplied to

The output end of this waveform acquisition memory 34 is connected to the input bus of the microprocessor 32. This microprocessor 32 includes a RUM 35 in which programs for calculation and control, reference data, filter coefficients for a low-pass filter having characteristics approximately corresponding to the frequency characteristics of the 5inx/x signal, etc. are stored in advance, and intermediate data, etc. A RAM 36 for temporarily storing the data is connected to each. Further, the output bus of the microprocessor 32 is connected to the input terminal of the buffer memory 33 and to each filter coefficient input terminal of the transversal filters 11 and 21. Note that the video signal obtained at the signal output terminal 37 of the ghost removal circuit connected to the output end of the IIR filter 20 is converted into an analog signal, for example, and then supplied to an image display circuit (not shown) or the like.

In the above configuration, the microprocessor 32 first
For example, just before the 18th horizontal period (18H or 281) 1) of each field, the switch 31 is set to the position shown, and the low-pass Set filter coefficients for each filter. As a result, the video signal of, for example, 18H or 281H inputted to the filter 11 via the terminal 30 is outputted from the filter in a form in which its high frequency noise component has been removed, and is stored in the waveform acquisition memory 34. Next, the filter coefficient of the microprocessor 32 and filter 11 is returned to the value before the low-pass filter coefficient was set, and then, at a predetermined timing, the contents of the memory 34 are read out and stored in the RAM.
36. The microprocessor 32 executes the above operation according to the 8-field sequence method of the BT^ (Broadcast Technology Development Council) standard, and as a result, the RAM
Based on the data obtained in step 36, the GCR signal (time series information) in the input video signal is reproduced. Next, the microprocessor 32 performs necessary processing on this GCR signal and then differentiates it to obtain a sin X/X signal corresponding to the rising edge of the GCR signal, that is, a sln The time series x(k) of the /X signal is reproduced and temporarily stored in the RAM 36.

Next, the microprocessor 32 outputs the signal x(k) in the RAM 36 and the signal shown in FIG.
The time series r of the reference sin X/X signal as shown in a>
(k), the filter coefficient h (k) for the FIR filter is calculated by the least square error method.

Next, the microprocessor 32 reads out the signal x(k) stored in the RAM 36 and stores it in the buffer memory 33, and also applies the filter coefficient h(k) to each of the transversal filters 11 during the vertical retrace period. At the same time as setting the transversal filter 11, the switch 31 is switched so that the signal x(k) in the buffer memory 33 is supplied to the transversal filter 11. In this case, the above signal x(
The output from the transversal filter 11 for the waveform k), ie, the signal y(k) as shown in FIG. 4, is stored in the waveform acquisition memory 34. When the above operation is completed, the microprocessor 32 returns the switch 31 to the illustrated state.

Next, the microprocessor 32 controls the waveform acquisition memory 34.
, the part of the signal y (k) after point Q, that is, the signal X (k
), and extract the residual ghost region, expressed as
The time series multi-values (k) are set with corresponding time relationships in each stage of the transversal filter 21 with their signs inverted.

According to the above configuration, the signal output terminal 3
Since the output 0(k) of the circuit obtained at terminal 7 is almost the same as the reference sin X/X signal r(k) as shown in FIG. It has almost been removed.

Another embodiment of the ghost removal circuit according to the present invention will be described with reference to an implementation method using a digital signal processor.

Figure 7 shows a digital signal processor (hereinafter referred to as DSP).
This figure shows the configuration of a ghost removal circuit according to the present invention, which aims to achieve higher speed by using the following. In this figure, FIR
The configuration itself in which the filter 40 and the IIR filter 50 are connected in cascade is the same as the configuration shown in FIG. In this case, the analog video signal input to the signal input terminal 60 is sequentially converted into, for example, 8-bit digital data at a predetermined sampling period by the A/D converter 61 and is input to the input terminal 40a of the FIR filter 40. Supplied. Further, from the output terminal 50b of the HR filter 50, a filtered video signal of, for example, 8 bits is sequentially supplied to a D/A converter 62, and from this D/A converter is supplied in analog form to an output terminal 63. . Further, an input end of a line memory 64 having a capacity sufficient to store a video signal within one horizontal line period is connected between the output end 40b of the FIR filter 40 and the input end 50a of the IIR filter 50. The output of the memory is connected to the input bus of the DSP 65. The DSP 65 is, for example, 7M5320C25 manufactured by Texas Instruments.
The chip-on ROM stores in advance a reference 5inx/x signal and a filter coefficient LPF (k) for a low-pass filter having characteristics approximately corresponding to the frequency characteristics of this signal. The DSP 65 also includes a RAM 6 which is used to store temporal data and serve as a working area.
6 is connected. Further, the output bus of this DSP 65 is connected to filter coefficient input terminals of the FIR filter 40 and the IIR filter 50, etc.

As shown in FIG. 8, the FIll filter 40 includes a variable delay element 42 that delays an input video signal by a time set by the DSP 65 and outputs the delayed signal, and a variable delay element 42 that delays the input video signal by a time set by the DSP 65 and outputs the delayed signal, and the output of the variable delay element and the input video signal. and a transversal filter 43-, which inputs these at terminals a and b, respectively.
0, and three transversal filters 43-1, 43-2, and 43-3 connected in cascade to this transversal filter 43-0 via their output terminals C and d. The above transversal filter 43-0.4
3-1.43-2.43-3 each have a similar configuration,
The detailed configuration of one of them is shown in FIG.

In Fig. 9, input terminal a (8-bit input) of the transversal filter is connected to delay element 4 of l clocker.
4 input terminals are connected, and the output terminals of this delay element are connected to 16 multipliers 46-0.46-1.46-2,...46-
15 input terminals, and is also connected to the output terminal C. Each of the above multipliers 46-〇, 46-1゜46
-2, . . . 46-15 are supplied with filter coefficients from the DSP 65 as multiplication coefficients. Furthermore, between the other input terminal b (16-bit input) and the other output terminal d of this transversal filter, 17 one-clock delay elements 47-0.47-1.47-2, . . .・47-
15.4716 between them adder t8-0.48-
1.48-2, . . . 4.8-15 are inserted in a cascade connection. Further, the multiplier 46-O146-
Each output of 1, 46-2, . . . 46-15 is sent to each corresponding adder 48-〇, 48-1゜48-2, .
- It is designed to be supplied to the other input terminals of 48-15, respectively.

Returning again to FIG. 8, the output terminal 40b of the FIR filter 4o and the output terminal d of the Sm transversal filter 43-3 are connected to the input terminal of the line memory 64, and are also connected to the input terminal 50a of the IIR filter 5o. It is connected. This input terminal 50a is connected to the input terminal of a transversal filter 51-0, and this transversal filter 51-o has seven transversal filters 51-1, 51-2, . , . . 51-7 are connected in cascade. In this case, each of the transversal filters 51-0.51-1.51-2, . . . 51-7 has a configuration similar to that shown in FIG. 9. Then, the output terminal d of the transversal filter 51-7
is connected to the output terminal 50 of the IIR filter 5o via a limiter 52 that limits 16-bit information to 8-bit information.
connected to b. Moreover, the output of the limiter 52 is
Variable delay element 53-0.53-1.53-2,...5
3-7 respectively, the transversal filter 51
-0°51-L 51-2, . . . 51-7 are fed back to large power terminals a, respectively. In this case, the variable delay elements 53-0.53-1.53-2, -53-
A delay amount of 7 days DSP and 65 days is set respectively.

Next, the operation of this embodiment having the above configuration will be explained with reference to the flowchart shown in FIG.

When a falling edge of the vertical synchronization signal of an odd field in the received video signal is detected by a circuit not shown,
The program shown in FIG. 10 is started by the DSP 65,
First, in block 100, initialization processing is performed.

In this block 100, a value "0" is set as a filter coefficient in the FIR filter 40 and the IIR filter 5o, respectively. That is, the DSP 65 includes transversal filters 43-2 to 43-3 and 51-0.
Each of the multipliers 46-0 to 46- in the multipliers 46-0 to 51-7
15 is set to the value "0" as a multiplication coefficient.Next, in block 101, the counter CNT is set to "0", and then the process proceeds to block 102.In block 102, the value "0" is set as a multiplication coefficient in In block 103, the low-pass filter coefficient LPF(k) previously stored in the chip-on ROM of the DSP 65 is set as a filter coefficient in the FIR filter 40.Next, in block 103, the data stored in the line memory 64, i.e., the above-mentioned Low-pass filter coefficient LPF (k)
The GCR signal (or pedestal signal) from which high frequency noise has been removed by the filter 40 based on the RAM 66
is memorized. Then, at block 104, the FI
Each filter coefficient of the R filter 40 is returned to the value immediately before the block 102, and "1" is added to the counter CNT. Next, in block 105, it is determined whether the counter CNT has reached, for example, a multiple of "8'""8N",
If it has not been reached, the process returns to block 102, and if it has been reached, it proceeds to the next block 106. That is, in blocks 102 to 105 described above, for example, B
In order to apply the TA standard 8 field sequence method,
GCR signals and pedestal signals for consecutive multiple fields of 8 are collected. Next, in block 106, the GCR signal and pedestal signal collected as described above are processed based on the 8-field sequence method to obtain an averaged GCR signal, and further, the averaged GCR signal obtained in this manner is A sin×/× signal x(k) that has suffered a coast disturbance is obtained by taking the difference between the GCR signal obtained by the signal and a signal shifted by one clock of the GCR signal (that is, differentiating the GCR signal). The signal x (k) thus determined is stored in RAM 66.

Next, in block 107, time series information r(k) of the reference sin X/X signal stored in advance in the chip-on ROM of the DSP 65 and the signal
FIR filter 4 using the least squares error method from (k) and
0 filter coefficient h(k) (in this example, there are 64 values, and hereinafter, these filter coefficients will be referred to as fir
(represented by k>) are calculated and temporarily stored in the RAM 66. Proceeding next to block 108, X (
When the signal x' (k) is input to an FIR filter with a filter coefficient fir(k), the signal x' (k) is output from the FIR filter.
) is calculated by calculation. That is, the DSP 65 calculates the following for each k after point Q in FIG. X' (k) obtained in this way
is temporarily stored in RAM 66. Next block 109
In this step, the DSP 65 obtains a predetermined number (eight in this example) of peaks from the above x' (k), and calculates a predetermined number (16 in this example) of x' consecutively centering on each of these peaks. (k) are each extracted (these data serve as filter coefficients of the IIR filter 5o, and are hereinafter expressed as 1ir(k)). The DSP 65 then stores these eight data groups, each consisting of 16 pieces of data 1ir(k), in the RAM 66. Further, the DSP 65 calculates the IIR based on each time from the 0 point in FIG. 4 to the first data of each data group.
Each delay of the filter jldly? , d+y6, dly5,
..., dlyO is calculated, and each of these delay amounts is stored in RAM 6.
6.

Next, in block 110, each filter coefficient fir (k), i ir (k) calculated as described above is
and delay amount clly? , d+ys, dly5,...
dlyO is set in the 14R filter 40 and the FIR filter 50 in a predetermined horizontal period within the vertical bright line erasure period. That is, the filter coefficient f ir (k) is set as a multiplication coefficient in the multipliers 46-0 to 46-15 of the transversal filters 43-0 to 43-3, respectively. Further, the delay amounts dly7 to dlyO are set to the variable delay elements 53-7 to 53-0, respectively, and the values obtained by inverting the sign of each data of the filter coefficient i i r (k) are set to the respective transversal filters 517 to 51-
0 multipliers 46-0 to 46-15 as multiplication coefficients.

When the above processing is completed, this program will block 1
01, and thereafter the same processing as described above is repeated.

According to the above embodiment, the filter coefficients fir(k) and i
Since the signal x (k) used to calculate i r (k) has been subjected to high-frequency noise removal processing using the low-pass filter coefficient LPF (k), more accurate ghost removal operation can be obtained. .

[Brief explanation of the drawing]

Fig. 2 is a block diagram for explaining the operating principle of the ghost removal circuit according to the present invention, Fig. 2 is a waveform diagram of the received ghost removal reference signal which has suffered ghost interference, and Fig. 3(a) is a block diagram of the ghost removal circuit according to the present invention. A waveform diagram of the ghost removal reference signal stored in advance in the memory of the ghost removal circuit according to the invention; FIG. 3(b) is a frequency characteristic diagram of the ghost removal reference signal; FIG. FIG. 5 is a waveform diagram of the received ghost removal reference signal outputted from the ghost removal circuit according to the present invention, and FIG. 6 is an embodiment of the ghost removal circuit according to the present invention. FIG. 7 is a block diagram showing the configuration of another embodiment of the ghost removal circuit according to the present invention, and FIG. 8 shows detailed information of the acyclic filter and the cyclic filter in the same embodiment. FIG. 9 is a block diagram showing the detailed structure of the transversal filter that constitutes these filters, and FIG. 10 is a block diagram showing the configuration.
9 is a flowchart for explaining the operation of the embodiment of FIG. 8. 10... Acyclic filter (FIR filter), l
l... Transversal filter, 20... Recursive filter (If filter), 21... Transversal filter, 22... Adder, 31... Switch, 32... Microprocessor, 33... ... Buffer memory, 34... Waveform acquisition memory, 35... ROM
, 36...RAM, 40...Acyclic filter (FIR filter) 43-0 to 43-3...Transversal filter, 50...Cyclic filter (
IJR filter), 51-0 to 51-7...Transversal filter, 64...Line memory, 65.
・・Digital signal processor (DSP), 66・
...RAM, M...Memory. Figure 6

Claims (1)

[Claims] 1. In a ghost removal circuit configured by cascade-connecting an acyclic filter and a cyclic filter, an input that is provided on the output side of the acyclic filter and that has passed through the acyclic filter. a first memory for storing a received ghost removal reference signal in a video signal; a second memory pre-stored with a predetermined ghost removal reference signal; and a second memory for storing a ghost removal reference signal for the acyclic filter. a third memory pre-stored with a first filter coefficient group for imparting a low-pass filter characteristic substantially corresponding to the frequency characteristic of the input video signal; The first
a first setting means for setting a group of filter coefficients in the acyclic filter; and a first setting means for setting a group of filter coefficients in the acyclic filter; calculation means for calculating a second filter coefficient group for ghost removal for the recursive type filter and a third filter coefficient group for ghost removal for the recursive type filter, respectively; a second setting means for setting a group of filter coefficients for each of the acyclic filter and the cyclic filter.