JPH04357783A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To share the same transversal filter and arithmetic circuit with at the time of recording and reproduction, to eliminate the distortion of the radio waves transmission system such as ghost at the time of recording, and to correct the distortion of waveform and the deterioration of frequency characteristic generated in recording and reproduction at the time of reproduction. CONSTITUTION:At the time of recording, transversal filter 6 deghost elimination processing to be corrected by an input video signal from a switch 4, and the recording is performed by replacing or adding a new GCR signal from a GCR signal generation circuit 28 by a switch 12. The GCR signal is extracted from a video signal by a GCR extraction circuit 10. The GCR signal is extracted from the video signal by the GCR extraction circuit 10, and compared with the reference signal from a reference waveform generation circuit 9 by a tap coefficient control circuit 8 so as to set the optimum tap coefficient to the transversal filter 6. At the time of reproduction, a reproduction luminance signal passes through a switch 4, and the ghost elimination processing is executed by the GCR signal added by the transversal filter 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus equipped with a ghost canceller and capable of removing ghosts from video signals and improving waveform response or frequency characteristics.

0002

2. Description of the Related Art Ghost disturbances caused by high-rise buildings and the like are the biggest cause of picture quality deterioration in terrestrial television broadcasting. As a countermeasure for this, the broadcasting station uses GCR (Ghost Cancel Ref) to remove ghosts.
A ghost cancellation system has been developed in which a reference signal called an erence signal is added to a video signal and transmitted, and the receiving side removes ghosts from the video signal based on this reference signal. It has already been put into practical use. Details regarding such a system can be found in, for example, the Technical Report of the Television Society Vol. 13, No. 32, pp. 19-24 “
Since it is described in many documents such as the paper entitled "Specification Setting of GCR Signal System," only the main points will be explained here.

The GCR signal has a waveform as shown in FIG. 9(a), and the rising characteristic W(N) of the ringing portion is expressed by equation 1 shown in FIG. Function f in equation (1)
(n) is the sinX/X pulse multiplied by the window function h(n),
It is sampled discretely at Δt, and is shown in FIG.
It is expressed by Equation 2. Note that in equation 2, fsc=3
．． 579545MHZ, f1=4.177447MHZ
=265.5fH (fH is the horizontal scanning frequency, 1
5.73426KHZ), t0 is the 50% time of waveform rise. The window function h(n) that makes the spectrum of the GCR signal a standard curve is expressed by Equation 3 in FIG.

On the broadcasting station side, the GCR signal shown in FIG. 9(a) and the pedestal signal shown in FIG. It is inserted at a predetermined position in the blanking period.

On the receiving side, the synchronization signal and burst signal are removed by calculation between fields, and the burst signal shown in FIG. 9(c) is generated.
Obtain signal S(GCR). That is, 8 shown in FIG.
If the insertion line signals in each field sent in the field sequence are S1 to S8, then the bar
The signal S(GCR) is obtained by the calculation expressed by Equation 4 in FIG.

When this bar signal S (GCR) is differentiated (one clock difference), a sinX/X pulse waveform as shown in FIG. 9(d) is obtained from its leading edge. On the receiving side, a reference pulse signal in the form of an ideal sin Alternatively, distortion components are detected, and tap coefficients of the transversal filter are calculated from them. This tap coefficient is calculated so that the pulse signal after passing through this transversal filter (FIG. 9(d)) is equal to the ideal reference pulse signal.
When the signal passes through the monkey filter, a high-quality video signal is obtained in which ghosts and transmission distortion are removed, and there is no deterioration in frequency characteristics. Such devices on the receiving side are called ghost cancellers or image equalizers, and an example is given in the Technical Report of the Television Society of Japan.
ol. 13, No. 32, pp. 31-36 “GCR
It was introduced in a paper titled ``Compatible Ghost Canceller''. By incorporating a ghost canceller for home stationary VTRs, the video signals of received broadcasts can be corrected as described above before being recorded, resulting in high-quality images free of ghosts. Video can be played.

[0007]

[Problems to be Solved by the Invention] As described above, the ghost cancellation system not only eliminates ghosts contained in video signals, but also eliminates distortion in the transmission system and corrects frequency characteristics. Although it is an excellent system that can be applied, the ghost canceller is relatively expensive as a home-use device because it requires a high-order transversal filter and a complicated arithmetic circuit. In conventional magnetic recording and reproducing devices, such expensive devices are used only to remove ghosts during recording, and although they are expensive devices, their scope of use is narrow and there are problems in terms of cost performance. Ta.

An object of the present invention is to solve this problem, to make more effective use of the transversal filter and arithmetic circuit that were conventionally provided in recording systems for ghost removal, and to improve image quality or functionality. It is an object of the present invention to provide a magnetic recording and reproducing device that can be further promoted.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a correction means consisting of a transversal filter, a GCR signal extraction means, a reference signal generation means, and a tap coefficient control means, and a transversal filter. A switch for selecting a recording signal or a reproduction signal as an input to the filter, a GCR signal generating means, and a means for adding the GCR signal from the GCR signal generating means to the output signal of the transversal filter are provided.

Furthermore, the present invention makes the waveform of the reference signal from the reference signal generation circuit variable in accordance with the reproduction mode. This makes it possible to respond to characteristics and perform adaptive processing.

Furthermore, the present invention provides G added by the adding means.
The level of the CR signal is attenuated from the normal GCR signal level in the recording signal.

0012

[Operation] The switch for selecting the input of the transversal filter selects the recorded signal during recording and the reproduced signal during playback, so that the correction means
The GCR signal inserted into the input video signal operates to remove ghosts contained in the input video signal, and during playback, the GCR signal added by the additional means allows the recording and playback of the playback video signal to be performed. It operates to correct the resulting waveform deterioration and frequency characteristic deterioration. This allows the transversal filter to be used appropriately and effectively. Moreover, by using a means for adding a GCR signal, even a recorded signal to which no GCR signal is added can be converted into a GCR signal.
Since the signal is added and recorded and reproduced, waveform deterioration and frequency characteristic deterioration that occur during recording and reproduction can be corrected.

Furthermore, when the reference signal waveform is changed, the tap coefficients of the transversal filter are controlled so that the GCR signal waveform extracted from the video signal and the changed reference signal waveform are equal, so that the frequency of the output video signal changes. Characteristics etc. are changed. This makes it possible to change characteristics depending on the mode and perform adaptive processing according to the state of the video signal. By performing the recording process while attenuating only the GCR signal, it is possible to prevent the GCR signal from being clipped during the recording process.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus according to the present invention, in which 1 is a video signal input terminal, 2 is a tuner, 3 and 4 switches, and 5 is an A/D (analog/digital) terminal. ) converter, 6 is a transversal filter, 7 is a D/A (analog/digital) converter, 8
1 is a tap coefficient control circuit, 9 is a reference waveform generation circuit, 10 is a GCR signal extraction circuit, 11 is a GCR timing generation circuit, 12 is a switch, 13 is Y/C (luminance signal/chrominance signal)
Separation circuit, 14 is a luminance signal recording processing circuit, 15 is a color signal recording processing circuit, 16 is an addition circuit, 17 is a recording amplifier, 1
8 and 19 are heads, 20 is tape, 21 is preamplifier,
22 is a luminance signal reproduction processing circuit, 23 is a color signal reproduction processing circuit, 24 is a delay circuit, 25 is an addition circuit, 26 is a switch, and 27 is a video signal output terminal 28 is a GCR signal generation circuit.

Next, the operation of this embodiment will be explained. First, the operation during recording will be explained. In FIG. 1, switches 4 and 26 are closed to the R side during recording, and when the switch 3 is closed to the a side, external inputs such as from a video camera are input, and when it is closed to the b side, external inputs are received from the built-in tuner 2. Select the received video signal.

The video signal from the switch is converted into a digital signal by an A/D converter 5, passed through a transversal filter 6 and a switch 12, and then converted to a digital signal by a D/A converter 7.
and converted back into an analog signal. Tap coefficient control circuit 8, reference waveform generation circuit 9, GCR signal extraction circuit 10
The GCR timing generation circuit 11 has a configuration similar to that of a conventional ghost canceller, and controls the transversal filter 6 to remove ghosts and transmission distortion from the video signal. That is, GCR timing generation circuit 1
1 generates a GCR timing signal A representing the period in which the GCR signal exists in the insertion line of each field shown in FIG. 11 in the output signal of the A/D converter 5. G.C.R.
The signal extraction circuit 10 extracts the period of the GCR timing signal A in the output signal B of the transversal filter 6. The tap coefficient control circuit 8 includes a GCR signal extraction circuit 10
The output signal C of is subjected to the calculation shown in equation 4 in FIG.
A pulse signal as shown in d) is obtained, and the tap coefficients of the transversal filter 6 are set so that this pulse signal C matches the ideal pulse signal from the reference waveform generation circuit 9.

Note that the switch 12 is normally closed to the c side under the control of the GCR timing generation circuit 11, and is closed to the d side at the insertion line of each field shown in FIG. As a result, the GCR signal from the GCR signal generation circuit 28 is added to the external input video signal from the input terminal 1.
In the received video signal from the tuner 2, the GCR signal added to it is the GCR signal from the GCR signal generation circuit 28.
Replaced with signal.

The video signal output from the D/A converter 7 is processed and recorded in the same manner as in a conventional magnetic recording/reproducing device. That is, the video signal output from the D/A converter 7 is supplied to the Y/C separation circuit 13 where it is separated into a luminance signal and a color signal, and the luminance signal is subjected to pre-emphasis and clipping in the luminance signal recording processing circuit 14. , FM modulation, etc., and the color signal is subjected to processing such as burst pre-emphasis, frequency conversion, etc. in a color signal recording processing circuit 15. These processed luminance signals and color signals are combined in an adder circuit 16, amplified in a recording amplifier 17, and then supplied to a head 18 and recorded on a tape 20. At the same time, the switch 26
has selected the b side, and the video signal from which the ghost has been removed output from the D/A converter 7 passes through the switch 26.
The signal is supplied from the output terminal 27 to a monitor (not shown) or the like.

Next, the operation of this embodiment during reproduction will be explained. At this time, the switches 4 and 26 are closed to the P side. The video signal reproduced from the tape 20 by the head 19 is amplified by a preamplifier 21, and the luminance signal is subjected to processing such as FM demodulation and de-emphasis in a luminance signal reproduction processing circuit 22. This reproduced luminance signal passes through a switch 4, is converted into a digital signal by an A/D converter 5, and then is supplied to a D/A converter 7 via a transversal filter 6 and a switch 12, where it is converted into an analog signal. The signal is returned and supplied to the adder circuit 25. At this time, tap coefficient control circuit 8, reference waveform generation circuit 9, GCR signal extraction circuit 1
The 0 and GCR timing generation circuit 11 uses the GCR signal added by the switch 12 during recording, operates as a moving ghost canceller in the same way as during recording, and corrects waveform distortion and deterioration of frequency characteristics of the reproduced luminance signal.

On the other hand, the reproduced color signal from the preamplifier 21 is subjected to processing such as frequency conversion and burst de-emphasis in a color signal reproduction processing circuit 23, and then sent to the A/D converter 5 of the reproduced luminance signal in a delay circuit 24. The signal is delayed by a delay position equal to the delay position from the D/A converter 7 to the D/A converter 7, is supplied to the adder circuit 25, and is added to the reproduced luminance signal from the D/A converter 7. The reproduced video signal obtained by this adder circuit 25 is transmitted to the switch 2
6 and is supplied to a monitor or the like via an output terminal 27.

FIG. 2 shows the tap coefficient control circuit 8 in FIG.
8a is a differential circuit, 8b is a subtraction circuit, 8c is a coefficient circuit, 8d is an addition circuit,
8e is a tap coefficient memory.

In the figure, the GCR extraction circuit 10 (FIG.
) is subjected to arithmetic processing as shown in equation 4 in FIG. 10 by the difference circuit 8a, and becomes a pulse signal with a waveform as shown in FIG. 9(d). This pulse signal is supplied from the reference waveform generation circuit 9 (FIG. 1) and subtracted from the reference waveform D by the subtraction circuit 8b.
Distortion components included in the pulse signal are detected. This distortion component is multiplied by α in the coefficient circuit 8c, added to the previously obtained tap coefficient E output from the tap coefficient memory 56 in the adder circuit 8d, and is added as a new tap coefficient to the tap coefficient memory 8e.
At the same time, it is read out and applied to the transversal filter 6. In this case, the addition circuit 8d performs the addition so that the distortion component from the subtraction circuit 8b is reduced, and therefore the transversal filter 6 (FIG. 1)
The waveform distortion of the video signal B output from the video signal B is reduced. By repeating this sequential control periodically,
A video signal with suppressed distortion is finally output from the transversal filter 6.

The above control algorithm is ZF (Zero
Forcing) method, tap coefficient memory 8
The previous tap coefficient output from e is Cj(n),
If the distortion component from the subtraction circuit 8b is Ej, the new tap coefficient Cj(n+1) can be expressed by the following equation.

Cj(n+1)=Cj(n)-αEj where Cj(n) is the j-th tap coefficient in the n-th correction.

FIG. 3 is a block diagram showing a specific example of the reference waveform generation circuit 9 in FIG. 1, in which 9a and 9b are waveform storage sections, and 9c is a multiplexer.

In the figure, waveform storage units 9a and 9b are as follows:
For example, it is a ROM (Read Only Memory) and stores data of different sinX/X pulse waveforms. These data are f(n
), but its frequency characteristics, that is, the value of f1 in Equation 2, are different between the waveform storage section 9a and the waveform storage section 9b. For example, the data stored in the waveform storage section 9a corresponds to f1=3 MHz, and the data stored in the waveform storage section 9b corresponds to f1=5 MHz. The multiplexer 9c is controlled by a mode signal F, and is, for example, a VHS mode that records and reproduces a band up to 3 MHz.
In S-VHS mode, which records and reproduces data up to 5 MHz, data from the waveform storage section 9a is stored in the waveform storage section 9a.
The data from b are selected and supplied as a reference signal D to the tap coefficient circuit 8 (FIG. 1).

As a result, the tap coefficients of the transversal filter 6 (FIG. 1) are determined so as to flatten the reproduced luminance signal in the frequency band up to 3 MHz or 5 MHz, depending on the mode. This allows for optimal correction.

Note that in FIG. 3, two waveform storage units 9a, 9
b is used for mode control, but it is possible to control the standard (SP) using three or more waveform storage units.
) playback and triple (EP) playback, etc., for more detailed control.

FIG. 4 shows the GCR signal extraction circuit 1 in FIG.
0 is a block diagram showing a specific example of 10a, 10
b is a subtraction circuit, 10c is a coefficient circuit, and 10d is a memory. The memory 10d performs a write operation for a period of the GCR timing signal A from the GCR timing generation circuit 11 (FIG. 1), and extracts the 9GCR signal from the output video signal of the transversal filter 6 (FIG. 1) supplied via the subtraction circuit 10b. Extract and import. The signal C output from the memory 10d is supplied to the tap coefficient control circuit 8 (FIG. 1) and also to the subtraction circuit 10a, where the difference between it and the output signal B of the transversal filter 6 (FIG. 1) is extracted. be done. This difference is multiplied by K (K<1) in the coefficient circuit 10c,
It is subtracted from signal B by subtraction circuit 10b. In this way, the GCR signal extraction circuit 10 has the configuration of a cyclic noise reducer, whereby noise is removed and a GCR signal with a good S/N ratio is obtained.

By the way, the regular level of the GCR signal added at the broadcasting station is determined to be 70 IRE, but in the case of this embodiment, the GC signal added by the switch 12 in FIG.
The level of the GCR signal from the R signal generation circuit 28 is set to a value smaller than this, for example, about 35 IRE. This is to prevent the GCR signal from being clipped due to pre-emphasis and clip processing in the luminance signal recording processing circuit 14. However, in this case, during playback, the tap coefficient control circuit 8 is controlled by the GCR signal extraction circuit 10, etc.
The tap coefficient control circuit 8 doubles the level of the reproduced GCR signal that is compared with the GCR signal, or 1/2 times the level of the reference signal D from the reference waveform generation circuit 9.
To make it possible to compare a CR signal with a reference signal D at the same level. As a result, the S/N of the reproduced GCR signal deteriorates, but by using the GCR signal extraction circuit 10 shown in FIG. - It is possible to improve the S/N of the reproduced GCR signal by performing processing such as signal processing, so there is no particular problem.

As described above, according to this embodiment, it is possible not only to remove the ghost of the received video signal during recording and to record a ghost-free video signal, but also to eliminate the ghost during recording. It is possible to monitor beautiful images without distortion, and during playback, the transversal filter 6 can be used to correct waveform distortion and frequency characteristic deterioration of the reproduced luminance signal that occurs during recording and playback.
can be effectively used to further improve the quality of the reproduced image.

FIG. 5 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention, in which 29 is an AGC (A
1, and parts corresponding to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

This embodiment differs from the embodiment shown in FIG. 1 in that an AGC circuit 28 is provided between the switch 4 and the A/D converter 5. The AGC circuit 28 is a circuit that controls the gain so that the level of the output video signal is constant. For example, the AGC circuit 28 detects the level of the synchronization signal portion of the input video signal and changes the gain according to the level. Since it is commonly used in home VTRs and the like, detailed explanation thereof will be omitted. However, although not shown in the embodiment of the above-mentioned drawings, magnetic recording and reproducing devices are generally provided with an AGC circuit, which is provided immediately before the Y/C separation circuit 13; In this embodiment, the AGC circuit is moved to the stage before the ghost canceller.

According to this embodiment, the level of the video signal (luminance signal during playback) input to the A/D converter 5 is kept constant, so the dynamic range of the A/D converter 5 can be effectively utilized. can be used to minimize quantization noise. Furthermore, since the gain from the A/D converter 5 to the D/A converter 7 is set to approximately 1, the level of the video signal output from the output terminal 27 is also kept constant. As a result, even if the level of the input video signal during recording fluctuates, the video on the monitor screen will have the normal brightness.

FIG. 6 is a block diagram showing still another embodiment of the magnetic recording/reproduction signal according to the present invention, in which 30 indicates Y/
C separation circuit, 31 is a switch, 32 and 33 are D/A converters, 34 is a luminance signal output terminal, 35 is a color signal output terminal, 36 is an A/D converter, and the parts correspond to those shown in FIG. are given the same reference numerals and redundant explanations will be omitted.

In FIG. 6, during recording, the switch 31 is set to R.
Closed on the side. The digital signal from the switch 12 is supplied to a Y/C separation circuit 30 and digitally separated into a luminance signal and a color signal. The luminance signal passes through the switch 31 and is converted back to an analog signal by the D/A converter 3, and then supplied to the luminance signal recording processing circuit 14, the adding circuit 25, and the output terminal 34. Further, the color signal is returned to an analog signal by the D/A converter 33 and is supplied to the color signal recording processing circuit 15, the addition circuit 25, and the output terminal 35.

During playback, the switch 31 is closed to the P side. The reproduced luminance signal from the preamplifier 21 is processed in the same manner as in the embodiment shown in FIG. On the other hand, the reproduced color signal from the preamplifier 21 is processed by a reproduced color signal processing circuit 37, converted to a digital signal by an A/D converter 36, and digitally processed by a comb filter by a Y/C separation circuit 30. and the D/A converter 35
The signal is converted into an analog color signal and supplied to the adder circuit 25 and the color signal output terminal 35. That is, the Y/C separation circuit 30 operates as a comb filter for removing crosstalk components from adjacent tracks from the color signal during reproduction. Generally, a Y/C separation circuit during recording is composed of a 1H (horizontal scanning period) delay circuit, an addition circuit, a subtraction circuit, etc., and consists of a part that passes only the luminance signal and a part that passes only the color signal. Therefore, the portion that only passes this color signal can be used as a color signal comb filter during reproduction.

As described above, in this embodiment, since the Y/C separation and the comb filter processing of the color signal during reproduction are performed digitally, there is no variation in delay time or gain, and high precision is achieved. Can be processed. Moreover, since the A/D converter and D/A converter for such digital processing can be used in common with the one for processing the transversal filter 6, the increase in cost is small.

FIG. 7 is a block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention, in which 37 is an AP
L (Average Picture Level
) is a detection circuit, and parts corresponding to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

In the figure, this embodiment differs from the embodiment shown in FIG. 1 in that an APL detection circuit 37 is provided. The APL detection circuit 37 detects the APL (brightness) of the input signal of the transversal filter 6 during recording and reproduction, and controls the reference waveform generation circuit 9 so as to generate an optimal reference signal D. For example, when the screen is dark (APL is low), noise on the screen is likely to be noticeable, so the frequency band of the reference signal D is narrowed. As a result, the tap coefficients of the transversal filter 6 are controlled by the operation of the tap coefficient control circuit 8 to narrow the frequency band of the reproduced luminance signal, so although the image becomes blurred, the S/N ratio improves. The noise becomes less noticeable. On the other hand, when the screen is bright (APL is high), the deterioration of details is easily noticeable, so the frequency band of the reference signal D is widened.

As described above, according to this embodiment, the frequency band of the video signal can be adaptively controlled during recording and playback according to the brightness of the screen, so that the apparent image quality can be improved. be able to.

FIG. 8 is a circuit block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention, in which 38 is a noise detection circuit, and parts corresponding to those in FIG. 1 are given the same reference numerals. .

In the figure, one point of this embodiment is that a noise detection circuit 38 is added. A noise detection circuit 38, which is different from the embodiment shown in FIG. 1, detects noise in the input signal of the transversal filter 6 during reproduction and controls the reference waveform generation circuit 9 so as to generate an optimal reference signal D. For example, when there is a lot of noise (poor S/N), the noise on the screen is likely to be noticeable, so the frequency band of the reference signal D is narrowed. As a result, the tap coefficients of the transversal filter 6 are controlled by the operation of the tap coefficient control circuit 8 to narrow the frequency band of the reproduced luminance signal, so although the image becomes blurred, the S/N ratio improves. The noise becomes less noticeable. On the other hand, when there is little noise (good S/N), the deterioration of details is easily noticeable, so the frequency band of the reference signal D is widened. The noise detection circuit 44 detects noise by detecting the signal level during the blanking period, for example.

As described above, according to this embodiment, S/
Since the frequency band of the video signal during recording and reproduction can be adaptively controlled according to N, the apparent image quality can be improved.

[0045] In FIG. 1, as shown by the broken line,
The GCR timing signal A may be supplied to the luminance signal recording processing circuit 14 and the luminance signal reproduction processing circuit 22, and the signal processing may be changed between the period of this GCR timing signal A and the other periods. For example, the brightness signal recording processing circuit 14 and the brightness signal reproduction processing circuit 22 are normally equipped with a noise canceller that treats small amplitude signals as noise and removes them to increase the S/N. When operated, the GCR signal is adversely affected. Therefore, during the period of this GCR signal, the GCR timing signal A causes the noise canceller to not perform the noise canceling operation and simply pass the GCR signal. This can be applied to other embodiments as well.

[0046]

[Effects of the Invention] As described above, according to the present invention, it is possible to remove distortion caused by the radio wave transmission system such as ghosts during recording, and to correct distortion and deterioration of frequency characteristics caused by recording and playback of a VTR during playback. . Furthermore, by providing an AGC circuit before the transversal filter, it is possible to monitor images with constant brightness during recording. Further, by changing the reference waveform, the frequency characteristics of the reproduced luminance signal can be made variable. Furthermore, by detecting APL and noise, the characteristics of the reproduced luminance signal can be adaptively changed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus according to the present invention.

FIG. 2 is a block diagram showing a specific example of the tap coefficient control circuit in FIG. 1;

FIG. 3 is a block diagram showing a specific example of the reference waveform generation circuit in FIG. 1;

FIG. 4 is a block diagram showing a specific example of the GCR signal extraction circuit in FIG. 1;

FIG. 5 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention.

FIG. 6 is a block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention.

FIG. 7 is a block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention.

FIG. 8 is a block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention.

FIG. 9 is an explanatory diagram of a ghost removal signal.

10 is a diagram showing a mathematical expression representing the ghost removal signal shown in FIG. 9 and a mathematical expression representing processing of the ghost removal signal; FIG.

FIG. 11 is a diagram showing the addition position of a ghost removal signal in a video signal.

[Explanation of symbols]

4 Switch 5 A/D converter 6 Transversal filter 7 D/A converter 8 Tap coefficient control circuit 9 Reference waveform generation circuit 10 GCR signal extraction circuit 11 GCR timing generation circuit 12 Switch 28 GCR signal generation circuit 29 AGC circuit 30 Y/C separation circuit 31, 32 D/A converter 36 A/D converter 37 APL detection circuit 38 Noise detection circuit

Claims (6)

[Claims] Claim 1: GCR (Ghost Cancel Refe) for ghost removal during the vertical blanking period.
In a magnetic recording and reproducing apparatus for recording and reproducing the composite video signal, the input means is provided with an input means for inputting a composite video signal into which the GCR signal is inserted and a composite video signal into which the GCR signal is not inserted, and for recording and reproducing the composite video signal. a first switch means for selecting said composite video signal from said composite video signal and selecting a reproduction luminance signal during reproduction;
a transversal filter to which the output signal of the switching means is supplied; a GCR signal extraction circuit for extracting the GCR signal inserted into the output signal of the transversal filter; and a reference signal generator for generating a reference signal having a reference waveform. and a tap coefficient control circuit that processes the GCR signal from the GCR signal extraction circuit and the reference signal and controls the tap coefficient of the transversal according to the calculation result, a correction means for correcting characteristics of an output signal, a GCR signal generation means for generating a GCR signal, and an output signal of the transversal filter is
When the R signal is an inserted composite signal, the inserted GCR signal is replaced with a GCR signal from the GCR signal generating means, and the output signal of the transversal filter is a composite signal without the GCR signal inserted. , the G from the GCR signal generating means is
A GCR signal adding means for adding a CR signal is provided, and the correction means can correct the characteristics of the composite signal into which the GCR signal is inserted during recording, and the characteristics of the reproduced luminance signal during playback. A magnetic recording/reproducing device characterized by: 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the GCR signal added by the GCR adding means has a level attenuated more than the GCR signal in the composite video signal from the input means. . 3. A magnetic recording and reproducing apparatus according to claim 1, wherein said reference signal generating means outputs a reference signal having a different reference waveform depending on the mode. 4. According to claim 1, an automatic gain control circuit is provided between the first switch means and the transversal filter, and an output signal of the transversal filter is output for monitoring. A magnetic recording and reproducing device. 5. According to claim 1, means for detecting the brightness of the output signal of the first switch means is provided, and the reference signal from the reference signal generation circuit can be changed according to the detection result of the means. A magnetic recording/reproducing device characterized by: 6. According to claim 1, means for detecting noise in the output signal of the first switch means is provided, and the reference signal from the reference signal generation circuit can be changed according to the detection result of the means. A magnetic recording/reproducing device characterized by: