JPS6065679A - Line noise suppressing circuit - Google Patents

Abstract

PURPOSE:To attain low cost and to improve cost performance by using an inexpensive narrow band glass delay line as a delay means to obtain a delay luminance signal. CONSTITUTION:A non-delay luminance signal from an input terminal 9 is divided into a low frequency component and a high frequency component, and a noise component without correlation for 1H is detected from the low frequency component and a delay luminance signal applied from an input terminal 10. The detected noise component is subtracted from the noise component mixed in the low frequency component and the low frequency component where the noise component is suppressed is obtained. Moreover, the low frequency component and the high frequency component are added and the delay luminance signal with excellent an S/N is obtained. Furthermore, the delay luminance signal applied from the input terminal 10 is narrowered for the frequency band, and an inexpensive narrow band glass delay line is used as a 1H delay means to obtain the delay luminance signal from the non-delay luminance signal in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a line noise suppression circuit suitable for use in a reproduction signal processing circuit such as a video tape recorder.

[Background of the invention]

A video signal reproduced from a video tape recorder or the like usually contains noise components L7, and if an image is directly reproduced using such a video signal, the reproduced image will be significantly degraded. For this reason, playback signal processing circuits such as video tape recorders are equipped with noise component removal circuits.
The image quality of the reproduced image is improved by improving the S/N ratio of the video signal. A line noise suppression circuit is used as a noise component removal circuit.

This line noise suppression circuit detects a noise component by using the fact that the video signal is IH (however, H has a correlation for each horizontal period, while noise has no correlation for each horizontal period, This detected noise component is used to cancel out and remove the noise component mixed into the video signal.

FIG. 1 is a block diagram showing a conventional example of a signal processing circuit for noise component removal including such a line noise suppression circuit, in which 1 is an input terminal, 2 is a frequency conversion circuit, and 3 is a surface acoustic wave filter.

4 is a glass delay line, 5 and 6 are same wave number demodulators, 7 is a line noise suppression circuit, and 8 is an output terminal.

A frequency-modulated reproduced luminance signal (hereinafter referred to as an FM luminance signal) from an input terminal 1 is converted to a high frequency by a frequency conversion circuit 2. This FM luminance signal converted to a high frequency is supplied to a surface acoustic wave filter B. The FM luminance signal from the surface acoustic wave filter 6 is supplied to the frequency demodulator 5 and demodulated, and is further supplied to the glass delay line 4 having a delay amount of 1H, where it is delayed by 11-1, and further frequency The signal is supplied to a demodulation circuit and demodulated. A luminance signal from the frequency demodulator auxiliary unit 5 (hereinafter referred to as a non-delayed luminance signal) and a luminance signal from the frequency demodulator 6 delayed by 11 degrees from this non-delayed luminance signal (hereinafter referred to as a delayed 4 degree signal) is supplied to the line noise suppression circuit 7, and 1
A luminance signal from which noise components having no correlation between H signals have been removed is obtained at the output terminal 8.

2 is a block diagram showing a conventional example of the line noise suppression circuit shown in FIG. 9 is a Mitsuta amplifier, 13 is an attenuator, 14 is a subtracter, and 15 is an output terminal.

In Figure 2.2, the non-delayed luminance signal from the input terminal 9 and the delayed luminance signal from the input terminal 10 are supplied to the subtracter 11 and the difference between them is taken, and the uncorrelated noise component is removed during 1H. It is taken out. This noise component is limited by the υmitter amplifier 12 and appropriately attenuated by the attenuator 13. After such processing is performed, attenuator 1 is subtracted from the non-delayed signal from input terminal 9 in subtraction 514.
The noise component from 3 is subtracted, and a luminance signal with reduced noise component is obtained at the output terminal 15. In this way, the noise component mixed into the reproduced luminance signal is removed, and reproduction with good image quality is achieved. An image is obtained.

Furthermore, such prior art does not compensate for dropouts, and H generation due to a 1H deviation for each field during fine still playback (a still playback method in which the same track is repeatedly played back using main and sub heads with the same azimuth angle). Image pitch compensation and CC'IR method (a method that allows chroma 100 between adjacent tracks to interleave with each other and prevents crosstalk between adjacent tracks)
It can also be used to complement 1'i of the 1H delay of the chroma signal caused by the comb filter, thereby simplifying the reproduced signal processing circuit.

On the other hand, the above-mentioned conventional technology uses a glass delay line to improve the reliability of delay, but this glass delay line allows FMS signals in a wide frequency range to pass through. must be set to a frequency that sufficiently violates the F'M41 degree belief. Therefore, a frequency conversion circuit 2 for converting FM brightness to a high frequency and a surface acoustic wave filter for extracting a sufficiently high frequency F'M signal from the output signal of this frequency conversion circuit 2 are required, which increases costs. In addition, an expensive glass delay amount 4 with a high passing center frequency must be used. Moreover, since the frequency demodulation circuit 5.6 demodulates the F M # degree signal of a sufficiently high frequency, power consumption increases.

In the end, even though the above-mentioned conventional technology can be used for various types of compensation as described above, it does not particularly simplify the configuration of the reproduced signal processing circuit, but leads to an increase in cost and power consumption. Therefore, it cannot be used in recent video tape recorders, etc., which aim to reduce costs and power consumption.

FIG. 3 is a block diagram showing a conventional example of a line noise suppression circuit, in which 16 is a low-pass filter, and parts corresponding to those in FIG. 2 are given the same reference numerals.

This prior art allows the use of inexpensive glass delay lines. The non-delayed luminance signal from the input terminal 9 is supplied to the subtracter 14, and is subtracted by a noise component having no correlation between 1H from the subtracter 14. This noise component is obtained as follows. The luminance signal from the subtracter 14 is passed through a low-pass filter (hereinafter referred to as "LPF") 1
6 and separates the low frequency components of this luminance signal.

The low frequency component of C is provided to subtraction 411.

On the other hand, a delayed luminance signal is supplied from the input terminal 10 to the subtracter 11, but this delayed 4 degree signal is supplied to the LPF 16 or 1'0
) is a signal with a frequency band equal to the supplied low frequency component. In other words, the delayed luminance signal is obtained by delaying the low-frequency component of the non-delayed luminance signal by 1H, and only the above-mentioned low-frequency component of the non-delayed luminance In passes through the passband Lppl,b. It is set as follows.

Next, the subtractor 11 subtracts the delayed 4th degree signal from the low frequency component of the non-delayed signal to obtain a noise component with no correlation between the signals. This noise component is limited by the limiter amplifier 12 and attenuated by the attenuator 13 to obtain the above noise component.

As described above, in this conventional technique, since the frequency band of the delayed luminance signal can be narrowed, it is possible to use an inexpensive glass delay line with a narrow pass band and a low pass center frequency as the 1H delay line. can. However, on the other hand, it is not possible to combine dropout compensation, image pitch compensation during fine still reproduction, and chroma signal delay compensation in the CC'IR system.

As described above, the conventional line noise suppression circuit is inexpensive and can also be used for video drop-act compensation, image pitch compensation during fine still playback, and chroma signal delay compensation during CCIR system. cannot be realized.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, to enable the use of an inexpensive narrowband glass delay line as a 1H delay means, to achieve a reduction in cost, and to provide dropout compensation and fine still playback. It is an object of the present invention to provide a line noise suppression circuit which can be used for both image pitch compensation and chroma signal delay compensation in the CCIF system, and can improve cost performance.

[Summary of the invention]

In order to achieve this objective, the present invention divides a non-delayed luminance signal into a low-frequency component and a high-frequency component, and divides the low-frequency component and the delayed luminance signal into a 1-11 function during 1H. detecting a noise component that is not present, subtracting the detected noise component from the low-frequency component to obtain a low-frequency component in which the noise component is suppressed;
The feature is that the low frequency component and the high frequency component are added.

In this way, by detecting the noise component from the low-frequency component of the non-delayed luminance signal and the delayed luminance monthly, and suppressing the noise component mixed into the primary frequency component, the delayed luminance signal can be used as the delayed luminance signal. A narrowband signal comparable to that of the low-frequency component can be obtained, and an inexpensive glass delay register with a narrow band can be used as a glass delay resistor with a delay amount of 1H to obtain such a delayed luminance signal. It should be noted that although the noise components of high frequency components are not suppressed, the noise components of high frequencies are not visually noticeable.

Furthermore, since the low frequency component of the non-delayed luminance signal and the delayed luminance signal have the same frequency band, the detected noise component is used to suppress the noise component from the delayed luminance signal, and Even if the high-frequency components divided from the delayed luminance signal are added, a wideband luminance signal with a predetermined frequency band secured can be similarly obtained. In the luminance signal obtained in this way, the low frequency component is before In compared to the high frequency component, and most of the energy of the luminance signal is concentrated in the low frequency component. from,
It can be regarded as a J44 message delayed by 1H.

That is, the present invention does not simply use the low-frequency component of the non-delayed luminance signal as the signal whose noise component is suppressed, but uses a delayed luminance signal in the same frequency band as the low-frequency component, and uses a non-delayed luminance signal with a good S/N ratio. Not only the delayed luminance signal but also the same delayed luminance signal (S/N) can be modified so as to obtain the same (S/N) delay luminance reliability, and from this, dropout compensation based on the 1H delay of the luminance signal, fine still playback. It can be used for both image pitch compensation and chroma signal delay compensation in the CCIR system.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram showing an embodiment of the line noise suppression circuit according to the present invention, in which 17 is a high-pass filter, 18 and 19 are low-pass filters, 20 is a subtracter, and 21 is an adder. , 2 and 6 are given the same reference numerals.

In FIG. 4, the non-delayed luminance signal from input terminal 9 is
LPF18 and high-pass fill (hereinafter referred to as HPF)
17. The LP 11118 has a time constant set so as to have a passband equal to the frequency band of the narrowband delayed luminance signal supplied from the input terminal 10, and from this, the low frequency component of the non-delayed luminance signal is extracted. The low frequency component of the non-delayed luminance signal whose frequency band is made equal to that of the delayed luminance signal by the LPF 18 is supplied to a subtracter 11.20.

Further, the I-IPF 17 separates the high frequency component of the non-delayed luminance signal having the same frequency band as the missing high frequency component of the delayed luminance signal. The subtracter 11 subtracts the 111 delayed luminance signal from the low frequency component of the non-delayed luminance signal, and extracts noise components that have no correlation between 1H in the frequency band of these two input signals. This noise component is amplified by the limiter 12, and its band is limited by the LPF 19.

The noise component subjected to such processing is attenuated by an attenuator 13 and then supplied to a subtracter 20. Therefore, the low frequency component of the non-delayed luminance signal is subtracted by this noise component, and the noise component mixed in this low frequency component is suppressed. The low-frequency component outputted from J13 for subtraction is added to the measured component of the non-delayed luminance signal output from HPF 17 in adder 21, and a wideband luminance signal with a predetermined frequency band secured is output to output terminal 15. is obtained.

As described above, in this embodiment, the frequency band of the delayed luminance signal supplied from the input terminal 10 can be narrowed, and the 1H delay is required to obtain the delayed luminance signal from the non-delayed luminance signal. As a means, an inexpensive glass delay line with a narrow passband can be used.

FIG. 5 is a block diagram showing another embodiment of the line noise suppression circuit according to the present invention, in which 22 is a subtracter, and parts corresponding to those in FIG. 4 are given the same reference numerals.

In FIG. 5, the non-delayed luminance signal from input terminal 9 is
It is supplied to the LPF 18 and the subtraction '#', 22.

Similar to the LPF 18 in FIG. 4, the LPF 18 separates low-frequency components of a non-delayed luminance signal having the same frequency band as the narrowband delayed luminance signal from the input terminal 10.

The subtracter 22 subtracts the separated low-frequency component and separates the high-frequency component from the non-delayed luminance signal.

In subtraction 611, the low frequency component of the non-delayed luminance signal is subtracted from the delayed luminance signal supplied from the input terminal 9. As a result,
Only the Noi woman I part that has no correlation between 1H is extracted.

This noise component is generated by the y-mitter amplifier 1 as shown in FIG.
The noise component subjected to such processing, whose amplitude is limited by 2 and whose frequency band is limited by LPF 19, is lengthened by attenuator 15, and subtracted from the low frequency component of the non-delayed luminance signal by subtracter 20. This suppresses the low-frequency noise component of the non-delayed luminance signal. The low frequency component of the non-delayed luminance signal in which the noise component has been suppressed and the high frequency component of the non-delayed luminance signal which is the output of the subtracter 22 are added by the adder 21, and a predetermined frequency band is secured at the output terminal 15. A wideband luminance signal can be obtained.

In this way, in this embodiment as well, an inexpensive narrowband glass delay line is used as the 1H delay means for obtaining a delayed luminance signal from a non-delayed luminance signal.
Since noise components with no correlation between them can be removed, costs can be reduced.

FIG. 6 is a block diagram showing a more functional embodiment of the line noise suppression circuit of the present invention, and parts corresponding to FIGS. 4 and 5 are given the same reference numerals. In FIG. 6, the non-delayed luminance signal from input terminal 9 is LPFls and II
2 and (((supplied). LPFls, like LPFls in FIG. It is meant to be collected.

A subtracter 11 subtracts the delayed luminance signal from the input terminal 9 from the low frequency component of the non-delayed luminance signal. As a result, low-frequency components of the luminance signal that have a correlation between 1a are eliminated, and noise components that have no correlation between 1a are extracted. As in FIG. 4, the amplitude of this noise component is limited by the 9-Mitsuta amplifier 12, and the frequency band is limited by lli[l by PF1q. The noise component that has undergone such processing is attenuated by attenuation 613, and subtracted from the uncontrolled yff and 4 degree signals by subtraction 52o.

At the output terminal 15, a broadband bright IW signal with a predetermined frequency band secured is obtained. This suppresses noise in the low frequency components of the non-delayed luminance signal.

Also, unlike in FIG. 4, the non-delayed luminance signal is
After subtracting the te and /is components, it is possible to ensure the wideband property of the #degrees without adding the high-frequency components of the non-delayed luminance signal as in 41a).

As described above, the configuration in FIG. 6 operates in the same way as in FIGS. 2 and 4, except for video dropout 7 compensation, image pitch compensation at fine step 1ν, CCI, 11. It is also used as delay compensation for chroma signals in the #f method, and has good cost performance.

The off-line diagram is a block diagram showing an example of application of the line noise suppression circuit according to the present invention, in which 23 is an input terminal, 24 is a glass delay line, 25 is a changeover switch circuit, 26, 27 is a frequency demodulator, 28, 29 . 30 is a changeover switch circuit, and parts corresponding to those in FIG. 5 are given the same reference numerals.

This application example is a combination of a line noise suppression circuit and a drop-act compensation circuit, and the embodiment shown in FIG. 5 is used as the line noise suppression circuit.

That is, in the off diagram, LPFls, subtractor 11.
20, 21.22, limiter amplifier 12, LPF'19
The attenuator 13 constitutes the embodiment shown in FIG. 5, and a changeover switch circuit 2B, 29.50 is added thereto. The non-delayed luminance signal from the frequency demodulator 26 is also input to the line noise suppression circuit from the frequency demodulator 2.
Delayed luminance signals are supplied from #7 to #J, respectively.

The glass delay line 24 and the changeover switch circuit 25 constitute a dropout compensation circuit, and the changeover switch circuit 25 normally closes to the contact a side and supplies the FM luminance signal from the input terminal 23 to the frequency demodulation fAg 26. ,
Contact b1#Ill is closed to supply the F'M luminance signal delayed by 1H by the glass delay line 24 to the frequency demodulator 26.

The FM luminance signal delayed by 1H in the glass delay image 24 is also sent to a frequency demodulator 27 . The passband of the glass delay line 24 is set so that the frequency band of the delayed luminance signal from the frequency demodulator 27 is equal to the passband of the LPF'1a.

- In the OFF diagram, during normal playback, the changeover switch circuits 28 and 29.50 are closed to the contact a side.
The operation is exactly the same as shown in the figure. When dropping out, switch y f-IZjJ 2a, 29, 3o are M Point side K
91 can be exchanged. Since the output of the changeover switch circuit 28 is the non-delayed 4th signal itself, the output signal of the subtracter 22 is zero. The output signal of the changeover switch circuit 29 is a delayed luminance signal from the frequency demodulator 27.

At the time of mud or blowout, the changeover switch circuit 25 also closes contact a.
Since dropout compensation is performed by switching from the side to the contact side, the output signal of the changeover switch circuit 3° also becomes a delayed luminance signal. As a result, the input signals of the two subtractors 110 are equal, and their output signal S is zero, so the output signal of the attenuation 515 is also zero. Therefore, the subtracter 2D receives the delayed luminance fN, which is the output signal of the changeover switch circuit 29.
In addition, the subtractor 22 is supplied to the number 21.
Although the output signal is zero, only the delayed luminance signal which is the output signal of the subtractor 2o is supplied, and a delayed 4 degree signal is obtained at the output terminal 15.Thereby, the drop act is compensated by the delayed luminance signal. In this way,
In this application example, the line noise suppression circuit can also be used as a noise/drop correction/prospect circuit.

An example of the application of off-diagrams is Fine Methyl Takao's l! 117
It can also be used to prevent image vertical shaking and improve image quality. 18 shows the structure of the rotating head cylinder of a magnetic tape recording/playback device for fine still playback.
This will be explained with reference to the figure.

In Figure 18, 31 is for rotation, C cylinder, and 32 is for C.
l-41 (first channel) head, 66 is CH2 (7
2 channel) head, and 64 is a CI5 (6 channel) head. The heads 52 and 35 are rotary heads used during normal (normal) L/reproduction, and are 180 degrees apart from each other.
are located 0 apart and have different azimuths from each other,
As is well known, diagonal tracks of successive fields of a magnetic tape are scanned for reproduction. When performing fine still playback, two heads trace the same track, so these two heads must have the same azimuth. In the example shown in Fig. 18, the CI'1 head 32 and the CH3 head 34 have equal azimuth angles, and
Fine still playback is performed using two rotating heads. However, because of the CH2 head 33, the CH3 head 34 is completely 18 times the same as the CH1 head 32.
They cannot face each other at the 0° position and are placed at a position shifted rearward in the direction of rotation. For this reason, the interval between the vertical synchronizing signals of the reproduced R degree signal differs from field to field, causing vertical shaking of the image. Therefore, if the Niyu luminance signal of the CHI head 32 is delayed by 1H, the reproduced luminance signal of the CHs head 34 is not delayed, and the reproduced luminance signals of both heads are combined, the delay amount of the CH5 head 34 will be compensated for by 4, and the image Vertical shaking can be prevented.

Therefore, in the OFF diagram, during normal reproduction, the changeover switch circuits 28, 29, and 30 are closed to the contact a side, and the operation is exactly the same as that in FIG. 5. During fine still playback, it operates as follows. CH5 head 34 (Figure 18)
During the reproduction scanning period, the switching switch is switched f times @ 28, 29.
30 is switched to the contact a side, and the operation described in FIG. 5 is performed. Further, during the reproduction scanning period of the CH1 head 32, the changeover switch circuit 2930 is kept closed to the contact a side on the second day, and the changeover switch circuit 2930 is switched to the contact side. For this,
The subtracter 11 outputs a noise component without tH1ljdK correlation, and the subtracter 20 outputs a delayed luminance signal from which this noise component has been removed. The subtracter 22 outputs the high frequency component of the non-delayed luminance signal, and the adder 21 adds the high frequency component of the non-delayed luminance signal and the delayed luminance signal, and outputs the result from the output terminal 15. Since the high frequency component of the non-delayed luminance Ig is added to the delayed luminance I100, a wide band of the luminance signal can be secured. High frequency component and low frequency component of non-delayed luminance signal, 1
Assuming that the H-delayed luminance signals are YH, Yr, Yn signals, the output signals in each state of the OFF diagram are as shown in Table 1 below. Figure 1 shows a modification of the rotary head cylinder, and contrary to Figure 18, the CHs head 54 is CHl-.

It is located forward in the rotational direction from the position facing the Rad 32.・Because of the second reason, the reproduction brightness signal of the CH1 head 62 is transferred to Cl-13 without delay,
g: Image vertical shaking during fine still playback can be reduced by IH delaying the signal. At this time, the output signal in the valley state of the OFF diagram is as shown in Figure 2 below.

The application example of Table 2 off-diagram can compensate for the delay of the chroma signal that occurs when using the CCIR method. In the CCIR system, since a 2H delay line is used as a comb filter for the chroma signal system during reproduction, the chroma signal is delayed by 1H, and there is a problem that the center of gravity does not match the luminance signal. Application example of off diagram 0
21 can be used to compensate for this chroma signal delay, and can also be used in the NTSC system where no chroma signal delay occurs.

In the OFF diagram, when the NTSC system is used, the changeover switch circuits 28, 29, and 30 are switched to the contact a side, and the operation described in FIG. 5 is performed. When dropout occurs, the changeover switch circuits 28, 29, and 30 are switched to the contact side, and a one-delayed luminance signal is obtained as described above. In this way, dropouts are compensated for with delayed video signals.

In the CCIR method, by switching the changeover switch circuit 28 to the contact a side and the changeover switch circuit 29.50 to the contact side, the output terminal 15
Next, a sum signal of the delayed luminance signal from which noise components having no correlation during 1H have been removed and the high-frequency components of the non-delayed luminance signal is obtained. To compensate for the delay in the chroma signal, it is sufficient to delay the low-frequency component of the luminance signal, which accounts for most of the energy; by adding the high-frequency component of the non-delayed luminance signal, the entire band of the luminance signal can be compensated for. can be secured. At the time of dropout, the changeover switch circuits 28, 29, and 30 are switched to the contact side, and a delayed luminance signal is obtained as in the NTSC system. In this case, since the delayed luminance signal is dropout compensated by the changeover switch circuit 25, dropout compensation is not performed by the video signal. The output signals in each state at this time are shown in Table 6.3 As mentioned above, the application example of the OFF diagram is simply a changeover circuit 28°29.30 added to the line noise suppression circuit shown in FIG. 1) It realizes four functions (removal of uncorrelated noise components, dropout compensation, image pitch compensation during fine still playback, and chroma signal delay compensation during CCIR method), so it is cost-effective for non-addicts. Good performance.

FIG. 10 is a circuit diagram specifically showing the line noise suppression circuit including the changeover switches 28, 29, 30 in the OFF diagram, and 41, 44, . 47 is a switch circuit; 42 is a circuit combining a subtracter, a limiter amplifier, and an LPF;
43 is an attenuator 1, 45, 46 is a subtracter, 48 is a switch control circuit, 49 to 54 are IC pins, 55 is an LPF, 57
and 58 are resistors, and 59 is a capacitor. IC pin 4
A delayed luminance signal and a non-delayed luminance signal are respectively supplied from 9.54. The capacitor f59 connected to the IC pin 53 is configured to take out the low frequency component of the non-delayed luminance signal having the same frequency band as the delayed luminance signal.

IC pins 50 and 51 are for an LPF that limits the band of noise components that have no correlation between 1H, and the passband is set by an external resistor and capacitor. The IC pin 52 is connected to a resistor 5 for setting the amount of attenuation of the attenuator 43.
7 and 58 are connected. Furthermore, resistors 57 and 5
8 determines the DC9 voltage of the IC bin 52 based on the ratio, so variations in the DC offset input to the subtracter 450 can be absorbed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to use an inexpensive glass delay line with a narrow passband as a delay means for obtaining a delayed luminance signal, thereby realizing cost reduction.
It is possible to obtain a wideband luminance signal in which noise components are sufficiently suppressed and a predetermined frequency band is secured, and by adding only a small amount of circuitry, noise components that have no correlation between IHs can be removed, and drop It can also be used for out compensation, image pitch compensation during fine still playback, and chroma signal delay compensation in the CCIR system, achieving dual functionality.
Moreover, it is possible to provide a line noise suppression circuit with very good cost performance.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a conventional signal processing circuit for noise component removal; Fig. 2 is a block diagram showing an example of a conventional line and noise suppression circuit in Fig. 1;
FIG. 4 is a block diagram showing an example of a song of a conventional line noise suppression circuit. 5 and 6 are block diagrams showing embodiments of the line noise suppression circuit according to the present invention, and off-line diagrams are block diagrams showing an example of application of the line noise suppression circuit according to the present invention,
FIGS. 8 and 9 are layout diagrams of the rotary head in the rotary head cylinder, and FIG. 10 is a circuit diagram specifically showing the line noise suppression circuit in an OFF diagram. 9...Non-delayed luminance signal input terminal, 10...Delayed luminance signal input terminal, 11...Subtractor, 12...9mi amplifier, 16...Liquid reducer, 15...Output terminal, 17
...High pass filter, 18, 19...Low pass filter, 2°...Subtractor, 21...Adder, 22.
...Subtractor. Representative Patent Attorney Akio Takahashi

Claims (1)

[Claims] Uncorrelated noise components for each IH are detected using a non-delayed luminance signal and a delayed luminance signal delayed by IH (where ■−■ is one horizontal period), and the detected In a line noise suppression circuit configured to cancel out and remove a noise component mixed into the non-delayed luminance signal by a noise component, a first means for dividing the non-delayed luminance signal into a low-frequency component and a high-frequency component; second means for subtracting between the spectral component and the delayed luminance signal; and third means for amplitude limiting and attenuating the output signal of the second means. a fourth means for subtracting the output signal of the third means from the low-frequency component; and a fifth means for adding the high-frequency component and the output signal of the fourth means; 1. A line noise suppression circuit characterized in that the delayed luminance signal is configured to be a narrowband I= signal for a 4-degree signal.