JPH0614297A - Video signal reproducing device - Google Patents

Abstract

PURPOSE:To suppress a pilot signal to be mixed as noise and to improve the frequency band of a reading low-pass transformation signal at the time of normal reproduction by controlling the setting of ATF and a variable de- emphasis section according to the operation mode discrimination result. CONSTITUTION:An operation mode discrimination section 35 discriminates whether a mode is a normal reproduction or a variable-speed reproduction. According to the discrimination result, the setting of an ATF trap section 21 and the variable de-emphasis section is controlled. At the time of the normal mode, the amplitude reduction for the pilot signal is not performed or it is made smaller than the degree of the amplitude reduction at the time of the variable-speed mode, and the degree of de-emphasis for a reproduced carrier chrominance signal is made smaller than that of the variable-speed mode. Thus, the pilot signal to be mixed as noise at the time of the variable-speed mode is suppressed and the degree of the de-emphasis processing is made small at the normal mode time, resulting in increasing the frequency band of the read low-pass transformation chrominance signal extracted from a synthesized recording signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a luminance signal and a carrier color signal which form a color video signal as a recording luminance signal and a recording carrier color signal, respectively, and frequency multiplex combines them with a pilot signal for automatic tracking control. The present invention relates to a video signal reproducing device for reading a composite recording signal from a magnetic tape on which the composite recording signal obtained is recorded using a magnetic head, and performing various processes on the read composite recording signal to reproduce a color video signal. .

[0002]

2. Description of the Related Art When a color video signal is recorded on a magnetic tape, it is obtained by recording the brightness signal as a high frequency side frequency modulation signal based on a brightness signal and a carrier color signal which compose the color video signal. A luminance signal (hereinafter, referred to as FM luminance signal) and a recording carrier color signal (hereinafter, referred to as low frequency converted color signal) obtained by frequency-converting the carrier color signal to the low frequency side are formed, and are formed as the FM luminance signal. A color video signal for recording, which is frequency-multiplexed combined with the low-pass conversion color signal, is recorded by a rotating magnetic head in a state in which inclined recording tracks are sequentially formed on the magnetic tape, and further, an audio signal is fixed magnetic. A recording method is adopted in which recording is performed by the head in a state in which an audio track extending along the running direction is formed on the magnetic tape. In addition to such a recording method, high-density recording of color video signals on a magnetic tape has been achieved, and the quality of audio signals recorded and reproduced even when the running speed of the magnetic tape is extremely low. In order to maintain good recording quality, a recording audio signal (hereinafter referred to as FM audio signal), which is a frequency-modulated signal, is frequency-multiplexed with a recording color video signal and is supplied to the rotary magnetic head. A recording method has also been proposed in which signals are recorded together with recording color video signals on inclined recording tracks on a magnetic tape.

Further, each of the inclined recording tracks on the magnetic tape is supposed to record one vertical period of the recording color video signal, that is, one field and an FM audio signal corresponding thereto, for example. , A pilot signal used for automatic tracking control performed so that a rotary magnetic head that reads a recording color video signal and an FM audio signal from a magnetic tape in a reproducing system properly follows each of the inclined recording tracks on the magnetic tape However, it has been proposed that the data be recorded in addition to the recording color video signal and the FM audio signal. In such a case, the pilot signals have, for example, frequencies 4 different from each other.
It is assumed that the signal is made up of four kinds of signals, which are sequentially recorded for each set of four inclined recording tracks adjacent to each other.

As described above, the composite recording signal obtained by frequency-multiplexing and combining the FM audio signal and the pilot signal with the recording color video signal composed of the FM luminance signal and the low frequency conversion color signal is sequentially arranged on the magnetic tape. Upon recording with the formed inclined recording track, the FM luminance signal is based on the original luminance signal, for example, the carrier frequency shift band has a frequency Fs = 4.2 M at the tip of the synchronizing signal of the luminance signal.
It becomes Hz and the white peak is frequency Fp = 5.4 MH
z is formed as a frequency modulation signal, and the low-pass conversion color signal is the original carrier color signal, for example, the color subcarrier frequency F.
c is about 743 KHz, which is frequency-converted to form, and the FM audio signal is based on the original audio signal.
For example, it is formed as a frequency modulation signal having a carrier frequency Fa of 1.5 MHz and a frequency shift width of about ± 100 to 150 KHz. In addition, the pilot signal has a frequency F
1, F2, F3, and F4, respectively, and four types of signals having substantially constant amplitudes are provided, and the frequencies are F1, F2, F3, and F.
4 are, for example, about 102.54 KHz, 118.95 KHz,
Selected to 148.69 KHz and 165.21 KHz.

Therefore, the composite recording signal obtained by frequency-multiplexing and combining the FM audio signal and the pilot signal with the recording color video signal is, for example, the characteristic diagram of FIG. 9 (vertical axis: level L, horizontal axis: frequency F). As shown in, the FM luminance signal Yf (Y
Is the original luminance signal), and the FM audio signal Af is arranged in a relatively narrow frequency band toward the lower limit side of the frequency band of the original luminance signal.
A relatively narrow frequency band, which is lower than the lower limit of the frequency band of the low-pass conversion color signal Cc, is assigned for the pilot signal, and the pilot signals P1, P2, and P2 are assigned to this low frequency band.
It is assumed that P3 and P4 are arranged.

When a magnetic tape having a large number of inclined recording tracks on which such combined recording signals are recorded is used for signal reproduction, each inclined recording track is scanned by a rotary magnetic head to rotate. The composite recording signal is read by the magnetic head, and the read FM luminance signal, the read low-frequency conversion color signal, and the read F are read from the read composite recording signal.
The M audio signal is taken out, and the reproduction luminance signal, the reproduction carrier color signal, and the reproduction audio signal are obtained based on each. At this time, when the read low-pass conversion color signal is extracted from the read combined recording signal, in the combined recording signal, with respect to the frequency band of the low-pass conversion color signal,
The frequency band of the pilot signal arranged on the low frequency side and the frequency band of the FM audio signal arranged on the high frequency side are set to be extremely close to each other, so that the frequency is extracted from the read composite recording signal. It is easy for the read pilot signal and the read FM audio signal to mix as noise into the read low-frequency converted color signal. In particular, if the reading of the composite recording signal from the magnetic tape by the rotary magnetic head is not performed in the normal reproduction operation mode but in the variable speed reproduction operation mode, it is extracted from the composite recording signal. The noise of the read pilot signal with respect to the read low-pass conversion color signal becomes significant.

Therefore, when the read low-frequency conversion color signal is extracted from the read composite recording signal, the read composite recording signal is included therein before the read low-frequency conversion color signal is extracted. The ATF trap unit, which is a trap unit that reduces the amplitude of the pilot signal, and the AFM trap unit, which is the trap unit that reduces the amplitude of the FM audio signal included therein. Then, the read low-pass conversion color signal is extracted from the combined recording signal in which the amplitude of the pilot signal and the amplitude of the FM audio signal are respectively reduced by the ATF trap unit and the AFM trap unit, and thus the read low-pass conversion that has been extracted. This means that the read pilot signal and the read FM audio signal mixed in the color signal as noise are suppressed.

[0008]

In this way, the pilot signal and F contained in the read composite recording signal are recorded.
The amplitude of each of the M audio signals depends on the ATF trap unit and the AF.
In reducing each by M trap part,
For example, mixing of the read pilot signal with respect to the read low-frequency conversion color signal extracted from the read combined recording signal as noise, particularly, the reading of the combined recording signal from the magnetic tape by the rotary magnetic head is a variable speed reproduction operation mode. Since it becomes remarkable when it is done under the ground, ATF
The degree of amplitude reduction with respect to the pilot signal by the trap portion is determined by reading the combined recording signal read out while the combined recording signal is read from the magnetic tape by the rotary magnetic head in the variable speed reproduction operation mode. It is set to a sufficiently large value so that the read pilot signal mixed as noise in the low-pass conversion color signal is effectively suppressed.

However, it is inevitably included in the read composite recording signal that the degree of amplitude reduction with respect to the pilot signal contained in the composite recording signal read by the ATF trap portion is set to be sufficiently large. The amplitude of the low-frequency part of the low-frequency carrier color signal is significantly reduced, and the phase rotation of the low-frequency carrier color signal included in the read composite recording signal due to the ATF trap is relatively large. Therefore, the frequency band of the read low-frequency conversion color signal extracted from the composite recording signal through the ATF trap portion is substantially narrowed on the low frequency side, and a relatively large phase rotation is generated. Will be. Then, such setting of the ATF trap section is performed by setting the pilot included in the read composite recording signal when the composite recording signal is read from the magnetic tape by the rotary magnetic head in the normal reproducing operation mode. The degree of amplitude reduction with respect to the signal is excessive, and therefore, there is a possibility that the read low-pass conversion color signal extracted from the composite recording signal through the ATF trap unit may have a reduced quality. And

In view of the above point, in the present invention, the luminance signal and the carrier color signal forming the color video signal are the FM luminance signal and the low frequency conversion color signal, respectively, and the FM luminance signal and the low frequency conversion color signal are The combined recording signal is read from the magnetic tape on which the combined recording signal obtained by frequency-multiplex combining with the pilot signal for automatic tracking control is recorded, and the read FM is read from the combined recording signal read. Synthetic recording from the magnetic tape by the rotary magnetic head unit in extracting the luminance signal and the read low-pass conversion color signal, and obtaining the reproduction luminance signal and the reproduction carrier color signal based on the read FM luminance signal and the read low-pass conversion color signal, respectively. When the signal is read in the variable speed reproduction operation mode, the read low range change extracted from the read composite recording signal is performed. The read pilot signal, which mixes the color signal as noise into it, can be effectively suppressed, and the reading of the composite recording signal from the magnetic tape by the rotary magnetic head can be performed under the normal reproduction operation mode. It is an object of the present invention to provide a video signal reproducing device capable of making a read low frequency band conversion color signal taken out from a read composite recording signal a high quality image having an improved frequency band in a state in which it is performed.

[0011]

In order to achieve the above object, a video signal reproducing apparatus according to the present invention has an FM luminance signal and a low-frequency conversion color based on a luminance signal and a carrier color signal forming a color image signal, respectively. From a magnetic tape on which a combined recording signal including a signal and a pilot signal for automatic tracking control is recorded by a rotating magnetic head unit to form a read combined signal, and a signal reading unit. A read-out FM luminance signal is extracted from the read combined signal, and a luminance signal reproduction circuit section for obtaining a reproduced luminance signal based on the extracted read FM luminance signal, and an amplitude of a pilot signal included in the read combined signal obtained from the signal reading section By a filter unit that extracts the read low-frequency conversion color signal from the read combined signal that has passed through the trap unit. In addition to the frequency conversion section that performs frequency conversion processing on the read low-pass conversion color signal that is read out to obtain a reproduction carrier color signal, and a de-emphasis section that performs de-emphasis processing on the reproduction carrier color signal obtained from the frequency conversion section. Then, when the signal reading unit is in the first state of reading the composite recording signal from the magnetic tape under the normal reproduction operation mode, the trap unit is in a state in which the amplitude reduction for the pilot signal is not performed or the amplitude reduction for the pilot signal is performed. The degree of reduction is set to be smaller than when the signal reading unit is in the second state of reading the composite recording signal from the magnetic tape under the variable speed reproduction operation mode, and the de-emphasis unit is provided with The degree of de-emphasis processing on the reproduced carrier color signal is set to be smaller than that when the signal reading unit is in the second state. Constructed and a that operation control unit.

[0012]

With this structure, in the video signal reproducing apparatus according to the present invention, the signal reading section is in the first state in which the composite recording signal is read from the magnetic tape under the normal reproducing operation mode. In some cases, the trap unit does not perform amplitude reduction on the pilot signal, or
The degree of amplitude reduction with respect to the pilot signal is set to be smaller than that in the second state in which the signal reading unit reads the composite recording signal from the magnetic tape under the variable speed reproduction operation mode. Further, the de-emphasis section is set to reduce the degree of de-emphasis processing for the reproduced carrier color signal as compared with the case where the signal reading section is in the second state. As a result, when the signal reading unit is in the second state, the trap unit is configured to sufficiently reduce the amplitude of the pilot signal included in the read combined signal, and the read signal extracted from the read combined signal that has passed through the trap unit is read. It is assumed that the read pilot signal mixed in the low-frequency converted color signal as noise is effectively suppressed. When the signal reading unit is in the first state, the trap unit does not reduce the amplitude of the pilot signal included in the read combined signal, or the signal reading unit determines the degree of the amplitude reduction of the pilot signal by the second reading unit. And the degree of de-emphasis processing for the reproduction carrier color signal is smaller than that when the signal reading section is in the second state. As a result, the read low-pass conversion color signal extracted from the read combined signal is of high quality with an improved frequency band.

[0013]

FIG. 1 shows an example of a video signal reproducing apparatus according to the present invention. This example shows a magnetic tape for recording a video signal on a magnetic tape and reproducing the video signal from the magnetic tape on which the video signal is recorded. A reproducing system in a recording / reproducing device (VTR) is formed.

In the example shown in FIG. 1, a composite recording signal Sm recorded with a large number of inclined recording tracks formed on the magnetic tape TP is scanned by the rotary magnetic heads 11A and 11B. Read by. At this time, a normal reproduction operation mode in which the running speed of the magnetic tape TP is substantially equal to the running speed of the magnetic tape TP when a large number of inclined recording tracks are formed on the magnetic tape TP during recording, and the magnetic tape T
The traveling speed of P is different from the traveling speed of the magnetic tape TP when a large number of inclined recording tracks are formed on the magnetic tape TP at the time of recording, and is, for example, a variable speed reproduction operation that is an integral multiple or a fraction Modes and are taken selectively. Therefore, the reading of the composite recording signal Sm from the magnetic tape TP by the rotary magnetic heads 11A and 11B is performed under the normal reproduction operation mode or the variable speed reproduction operation mode.

The composite recording signal Sm recorded on the magnetic tape TP has an FM luminance signal Yf and a low-pass conversion color which form a recording color video signal having the frequency band distribution as shown in FIG. 9 described above. Signal Cc, FM audio signal Af,
And pilot signals P1 to P1 for automatic tracking control
It is assumed that P4 is obtained by frequency multiplexing synthesis. Then, the FM luminance signal Y in the combined recording signal Sm
Each section corresponding to one field of the recording color video signal formed by f and the low frequency conversion color signal Cc is recorded on each of a number of inclined recording tracks formed on the magnetic tape TP.

The composite recording signal Sm is alternately read by the rotary magnetic heads 11A and 11B from a number of inclined recording tracks on the magnetic tape TP, and the rotary magnetic head 11 is read.
The read combined recording signals Sm obtained alternately from A and 11B respectively pass through the reproduction amplifiers 12A and 12B, and are sequentially taken out by the switch 13 to form a series of read combined signals Sr. Here, the rotary magnetic head 11A
And 11B, the reproduction / amplification units 12A and 12B, and the switch 13 together form a signal reading unit.

The read combined signal S obtained from the switch 13
r is a high-pass filter (HPF) 14 corresponding to the FM luminance signal Yf, a band-pass filter (BPF) 15 corresponding to the FM audio signal Af, and an AFM trap unit 16.
Is supplied to each of the. From the HPF 14, the FM luminance signal Yf in the read combined signal Sr is taken out as the read FM luminance signal Yfr. The read FM luminance signal Yfr from the HPF 14 is supplied to the luminance signal reproduction processing unit 17, and various processing including frequency demodulation processing is performed in the luminance signal reproduction processing unit 17. Then, from the luminance signal reproduction processing unit 17, a reproduction luminance signal Y ′ based on the read FM luminance signal Yfr.
Is obtained and is derived at the reproduction luminance signal output terminal 18. Further, the FM audio signal Af in the read combined signal Sr is taken out from the BPF 15 as the read FM audio signal Afr. Read FM audio signal Afr from BPF15
Is supplied to the audio signal reproduction processing unit 19, and various processing including frequency demodulation processing is performed in the audio signal reproduction processing unit 19. Then, a reproduction audio signal A ′ based on the read FM audio signal Afr is obtained from the audio signal reproduction processing unit 19 and is derived to the reproduction audio signal output terminal 20.

In the AFM trap section 16, the amplitude of the FM audio signal Af in the read combined signal Sr obtained from the switch 13 is reduced, and the amplitude of the FM audio signal Af obtained from the AFM trap section 16 is reduced. The read combined signal Sr ′ thus made is supplied to the ATF trap section 21. The ATF trap unit 21 selectively reduces the amplitude of each of the pilot signals P1 to P4 in the read combined signal Sr ′ from the AFM trap unit 16, and the pilot signals P1 to P4 obtained from the ATF trap unit 21. The read combined signal Sr ″ whose amplitudes have been selectively reduced are supplied to the low pass filter (LPF) 22.

The low-pass conversion color signal Cc in the read combined signal Sr ″ is taken out from the LPF 22 as a read low-pass conversion color signal Ccr. The low-pass conversion color signal Ccr read from the LPF 22 is automatically color controlled (ACC). The reproduction carrier color signal Cp ′, which is supplied to the section 23 and is obtained from the output terminal of the variable de-emphasis section 27 described later, is the control signal forming section 29.
The gain is controlled to be substantially constant by the control signal Scc supplied from the control signal generator 29 to the control signal generator 29. Subsequently, the read low frequency band conversion color signal Ccr obtained from the ACC section 23 is supplied to the frequency conversion section 24.

The frequency converter 24 includes a reference signal generator 3
A reference signal SC from the terminal 1 having a predetermined constant frequency is a signal SF from the terminal 32, which alternates between a high level and a low level for each field period in the color video signal, and a signal 1 from the color video signal from the terminal 33. In the reference signal phase inversion unit 34, which is supplied with the signal SH that alternately takes the high level and the low level for each line period, the phase is set for every other field period in the color video signal and for each line period therein. It is supplied as a reference signal SCI which causes inversion. Then, the frequency conversion unit 24 handles frequency conversion of the read low-frequency converted color signal Ccr to the high frequency side according to the reference signal SCI and phase inversion received by the low-frequency converted color signal Cc at the time of recording. Phase restoration is performed, and the carrier frequency is fc≈3. From the frequency converter 24.
A reproduction carrier color signal Cp of 58 MHz is obtained, which is B
It is derived through PF25.

Reproduction carrier color signal C obtained from BPF 25
The p is supplied to the variable de-emphasis unit 27 after the adjacent track crosstalk component is removed by the crosstalk removal unit 26. Variable de-emphasis unit 2
7, the reproduced carrier color signal Cp from the crosstalk removing unit 26 is subjected to de-emphasis processing related to the emphasis processing applied to the carrier color signal at the time of recording, and the variable de-emphasis unit 27 The reproduced carrier color signal Cp ′ that has been subjected to the de-emphasis process is obtained. Then, the reproduction carrier color signal Cp ′ from the variable de-emphasis unit 27 is subjected to noise reduction by using the vertical correlation in the noise reduction unit 28, and then is reproduced as a reproduction carrier color signal C ′ at a reproduction carrier color signal output terminal. 30.

Further, in the example shown in FIG. 1, an operation mode discriminating section 35 for discriminating the normal reproduction operation mode and the variable speed reproduction operation mode described above is provided. The operation mode determination unit 35 includes rotary magnetic heads 11A and 11B.
The reading of the composite recording signal Sm from the magnetic tape TP is distinguished by distinguishing between the state under the normal reproduction operation mode and the state under the variable speed reproduction operation mode. For example, the normal reproduction operation mode Of the operation mode discriminating signal SMC, which takes a low level under the variable speed reproduction operation mode, and takes a high level under the variable speed reproduction operation mode.
It is supplied to each of the control end of the F trap unit 21 and the control end of the variable de-emphasis unit 27, and the operation of each of the ATF trap unit 21 and the variable de-emphasis unit 27 is controlled according to the operation mode determination signal SMC. That is, the operation mode determination section 35 forms an operation control section for the ATF trap section 21 and the variable de-emphasis section 27.

Under the circumstances, the magnetic tape T formed by the rotary magnetic heads 11A and 11B under the variable speed reproduction operation mode.
When the composite recording signal Sm is read from P, the operation mode discriminating unit 35 outputs the high operation mode discriminating signal SMC to the control end of the ATF trap unit 21 and the variable de-emphasis unit 27. It is supplied to each of the control ends. The ATF trap unit 21 receives the operation mode determination signal SMC that takes a high level, and the AFM trap unit 1
The read synthesized signal Sr 'from S6 has a characteristic of sufficiently reducing the amplitude of each of the pilot signals P1 to P4. As a result, the frequency-gain characteristics of the portion including the AFM trap portion 16 and the ATF trap portion 21 are as shown in the characteristic diagram of FIG. 2 (horizontal axis: frequency F, vertical axis: gain G). Trap TRP for pilot signals P1 to P4 by
1 and a trap TRP2 for the FM audio signal Af by the AFM trap section 16 are formed. Therefore, the read combined signal S supplied to the LPF 22.
r ″ is such that the amplitudes of the pilot signals P1 to P4 and the FM audio signal Af contained therein are sufficiently reduced.

Further, the variable de-emphasis unit 27 responds to the reproduced carrier color signal Cp from the crosstalk removing unit 26 by the operation mode discrimination signal SMC having a high level.
When the de-emphasis processing corresponding to the emphasis processing applied to the carrier color signal at the time of recording is performed and the reproduced carrier color signal Cp is based on the carrier color signal having a large amplitude at the time of recording, FIG. The frequency-gain characteristics shown in the characteristic diagram of A (horizontal axis: frequency F, vertical axis: gain G) are exhibited, and the reproduced carrier color signal Cp is based on the carrier color signal of medium amplitude at the time of recording. In the case of, the frequency-gain characteristic as shown in the characteristic diagram of A of FIG. 5 (horizontal axis: frequency F, vertical axis: gain G) is exhibited,
Further, when the reproduced carrier color signal Cp is based on the carrier color signal having a small amplitude at the time of recording, as shown in the characteristic diagram of FIG. 6A (horizontal axis: frequency F, vertical axis: gain G). It exhibits the frequency-gain characteristic of.

The frequency band characteristic of the reproduction carrier color signal Cp 'or C'obtained at the output side of the variable de-emphasis unit 27 under the operation of the ATF trap unit 21 and the variable de-emphasis unit 27 as described above. Is
In the characteristic diagram of FIG. 7 (horizontal axis: frequency F, vertical axis: gain G), it becomes as shown by the curve FBV, and the reproduced carrier color signal Cp ′ or C ′ is the pilot signal P1 to P1.
It is assumed that the mixing of the noise component due to 4 is effectively suppressed.

On the other hand, when the rotary magnetic heads 11A and 11B read the composite recording signal Sm from the magnetic tape TP under the normal reproduction operation mode, the operation mode discriminating unit 35 outputs a low level. The operation mode determination signal SMC to be taken is supplied to each of the control end of the ATF trap unit 21 and the control end of the variable de-emphasis unit 27. The ATF trap unit 21 uses the operation mode determination signal SMC that takes a low level, and thus the pilot signal P1 in the read combined signal Sr ′ from the AFM trap unit 16 is generated.
The amplitude reduction for each of P4 to P4 is not performed. As a result, the frequency-gain characteristics of the portion including the AFM trap section 16 and the ATF trap section 21 are as shown in the characteristic diagram (horizontal axis: frequency F, vertical axis: gain G) of the pilot signals P1 to P1. It is assumed that the trap for P4 is not formed and only the trap TRP2 for the FM audio signal Af by the AFM trap unit 16 is formed. Therefore, in the read combined signal Sr ″ supplied to the LPF 22, the amplitude of the FM audio signal Af contained therein is sufficiently reduced, but the amplitude of each of the pilot signals P1 to P4 contained therein is not reduced. Further, the low-frequency conversion color signal Cc included in the read combined signal Sr ″ does not cause the phase rotation due to the ATF trap unit 21.

At this time, in the LPF 22, the read low-pass conversion color signal Ccr is extracted from the read combined signal Sr ″ whose amplitudes have not been reduced for each of the pilot signals P1 to P4 included therein, and the read low-pass conversion color is obtained. The signal Ccr is supposed to allow the pilot signals P1 to P4 to be mixed as noise in the low-frequency part thereof, but since the signal is in the normal reproduction operation mode, the degree of mixing is relatively small.

Further, the variable de-emphasis unit 27 responds to the reproduction carrier color signal Cp from the crosstalk removing unit 26 by the operation mode discrimination signal SMC having a low level, under the variable speed reproduction operation mode, to the rotary magnetic head 11A. And 1
Compared to the de-emphasis process when the composite recording signal Sm is read from the magnetic tape TP by 1B, the de-emphasis process having a smaller degree is performed, and the reproduction carrier color signal Cp is recorded. If it is based on a large-amplitude carrier color signal, A in FIG.
In the characteristic diagram of FIG. 4B (horizontal axis: frequency F, vertical axis: gain G), the gain change is considerably smaller than the frequency-gain characteristic shown in FIG. -If the reproduction carrier color signal Cp is based on the carrier color signal of medium amplitude at the time of recording, the reproduction carrier color signal Cp is compared with the frequency-gain characteristic shown in the characteristic diagram of FIG. The gain change is considerably small, and the frequency-gain characteristic as shown in the characteristic diagram of FIG. 5B (horizontal axis: frequency F, vertical axis: gain G) is exhibited, and further, the reproduction carrier color signal Cp is In the case of being based on the carrier color signal having a small amplitude at the time of recording, the frequency − shown in the characteristic diagram of FIG.
The change in gain is slightly smaller than the gain characteristic, as shown in FIG.
B has a frequency-gain characteristic as shown in a characteristic diagram (horizontal axis: frequency F, vertical axis: gain G). as a result,
In the reproduced carrier color signal Cp ′ obtained from the variable de-emphasis unit 27, the level of the signal component with respect to the noise component and the like caused by the mixed pilot signals P1 to P4 is relatively large, and as a result, the noise component is suppressed. Will be.

Such a variable de-emphasis unit 27
The frequency band characteristic of the reproduction carrier color signal Cp 'or C'obtained at the output side of the variable de-emphasis unit 27 under the operation by the curve F in the characteristic diagram of FIG.
As shown by BN, the frequency band characteristic is expanded to both the low frequency side and the high frequency side as compared with the frequency band characteristic shown by the curve FBV, and the gain increase on the high frequency side (ATF trap side) is remarkably improved. Therefore, the reproduced carrier color signal Cp 'or C'is of high quality.

FIG. 8 shows an equivalent circuit showing a concrete example of the variable de-emphasis unit 27. In a specific example represented by this equivalent circuit, a digital carrier color signal DP obtained by converting the reproduced carrier color signal Cp into a digital signal having a predetermined sampling period is supplied from the input terminal 41. The digital carrier color signal DP from the input terminal 41 is supplied to one of a pair of input ends of the subtraction section 42. Then, from the output terminal of the subtracting section 42, a digital carrier color signal DP 'corresponding to the reproduction carrier color signal Cp' converted into a digital signal having a predetermined sampling period is obtained, and the digital carrier color signal DP is obtained. 'Is
It is directly led to the output terminal 43, and the subtraction unit 44
Is supplied to one of the pair of input terminals and the level adjusting unit 45. In the level adjusting unit 45, the digital carrier color signal DP ′ is multiplied by a predetermined level control coefficient K to form a digital carrier color signal DK, and the digital carrier color signal DK is set to the sampling cycle of the digital carrier color signal DP. Through the delay unit 46 having the corresponding delay time,
It is supplied to the other of the pair of input terminals of the subtraction unit 44. In the subtracting unit 44, the digital carrier color signal DK is subtracted from the digital carrier color signal DP ′ to obtain a subtraction output signal DD, which is supplied to one of the pair of input terminals of the adding unit 47. .

The added output signal DA obtained from the output terminal of the adder 47 is supplied to the level adjusters 48 and 49, respectively. In the level adjuster 48, the addition output signal DA
Is multiplied by a variable level control coefficient GB to obtain an addition output signal D
AB is formed, and the addition output signal DAB is supplied to the other of the pair of input ends of the addition unit 47 through the delay unit 50 having a delay time corresponding to the sampling period of the digital carrier color signal DP. As a result, the addition section 47 performs addition by adding the addition output signal DAB to the subtraction output signal DD to form the addition output signal DA.

Further, in the level adjusting section 49, the addition output signal DA is multiplied by the variable level control coefficient GA to form the addition output signal DAA, and the addition output signal DAA is formed.
Are supplied to the other of the pair of input ends of the subtraction unit 42. As a result, the subtraction unit 42 performs subtraction by subtracting the addition output signal DAA from the digital carrier color signal DP to form the digital carrier color signal DP ′. The digital carrier color signal DP 'is digital-analog converted into a reproduced carrier color signal Cp'.

Under such circumstances, the level adjusting units 48 and 49 are provided.
An operation mode determination signal SMC sent from the operation mode determination unit 35 is supplied to each control end of the above through the terminal 51. Each of the variable level control coefficient GB in the level adjusting unit 48 and the variable level control coefficient GA in the level adjusting unit 49 has an operation mode determination signal SMC that takes a high level and an operation mode determination signal SM that takes a low level.
It takes a different value depending on C, and
The de-emphasis process for the digital carrier color signal DP is responsive to the operation mode discrimination signal SMC having a high level and the operation mode discrimination signal SMC having a low level, and accordingly, under the variable speed reproduction operation mode, the rotary magnetic head 11A.
And recording signal S from magnetic tape TP by 11B
It is changed as described above when m is read and when the composite recording signal Sm is read from the magnetic tape TP by the rotary magnetic heads 11A and 11B under the normal reproduction operation mode.

In the example shown in FIG. 1 described above, when the combined recording signal Sm is read from the magnetic tape TP by the rotary magnetic heads 11A and 11B under the normal reproduction operation mode, the ATF trap portion 21 is According to the present invention, the amplitude reduction is not performed for each of the pilot signals P1 to P4 in the read combined signal Sr ′ from the AFM trap section 16 by the operation mode determination signal SMC having a low level. The video signal reproducing device is not limited to such an example. For example, when the combined recording signal Sm is read from the magnetic tape TP by the rotary magnetic heads 11A and 11B under the normal reproduction operation mode, the ATF trap section 21 causes the pilot signals P1 to P1 to be included in the read combined signal Sr ′. The amplitude reduction is not performed for each P4, but the pilot signal P1 in the read combined signal Sr 'is set by the operation mode determination signal SMC that takes a low level.
For each of P4 to P4, compared to the case where the combined recording signal Sm is read from the magnetic tape TP by the rotary magnetic heads 11A and 11B under the variable speed reproduction operation mode, the degree of amplitude reduction that is made small is performed. It may be performed.

[0035]

As is apparent from the above description, according to the video signal reproducing apparatus of the present invention, when the signal reading unit reads the combined recording signal from the magnetic tape under the normal reproduction operation mode, the read combined signal is read. The trap section for the internal pilot signal does not perform amplitude reduction for the pilot signal, or the degree of amplitude reduction for the pilot signal is recorded by the signal reading section from the magnetic tape under the variable speed reproduction operation mode. The de-emphasis section determines the degree of de-emphasis processing for the reproduced carrier color signal, and the signal reading section controls the magnetic field under the variable speed reproduction operation mode. Since it is assumed to be smaller than when the composite recording signal is read from the tape, the signal reading unit operates in the variable speed reproduction operation mode. Of when reading the synthesized recording signals from the magnetic tape under, the trap portion intended for pilot signals in the read combined signal by performing sufficient amplitude reduction for the pilot signal included in the read combined signal,
The read low-pass conversion color signal extracted from the read combined signal that has passed through the trap portion, and the reproduction carrier color signal obtained based on the read low-frequency conversion color signal can be those in which noise due to the pilot signal is effectively suppressed, In addition, when the signal reading unit reads the composite recording signal from the magnetic tape in the normal reproduction operation mode, the trap unit for the pilot signal in the read composite signal reduces the amplitude of the pilot signal included in the read composite signal. Or the amplitude reduction of the pilot signal is made smaller than that when the signal reading unit reads the composite recording signal from the magnetic tape under the variable speed reproduction operation mode, and the reproduction carrier color by the de-emphasis unit is set. The signal reading unit determines the degree of de-emphasis processing for the signal under the variable speed playback operation mode. The read low-pass conversion color signal extracted from the read combined signal and the reproduction carrier color signal obtained based on the read low-pass converted color signal, which is smaller than when the combined recorded signal is read from the group, are of high quality with improved frequency band. You can do that.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an example of a video signal reproducing apparatus according to the present invention.

FIG. 2 is a characteristic diagram showing frequency-gain characteristics of a portion including a trap portion in the example shown in FIG.

FIG. 3 is a characteristic diagram showing frequency-gain characteristics of a portion including a trap portion in the example shown in FIG.

FIG. 4 is a characteristic diagram showing frequency-gain characteristics in the variable de-emphasis unit in the example shown in FIG.

5 is a characteristic diagram showing frequency-gain characteristics in the variable de-emphasis unit in the example shown in FIG.

FIG. 6 is a characteristic diagram showing frequency-gain characteristics in the variable de-emphasis unit in the example shown in FIG.

7 is a characteristic diagram showing frequency band characteristics of a reproduced carrier color signal in the example shown in FIG.

8 is a block connection diagram showing an equivalent circuit showing a specific example of the variable de-emphasis unit in the example shown in FIG. 1. FIG.

FIG. 9 is a characteristic diagram showing a frequency spectrum of a composite recording signal.

[Explanation of symbols]

 11A, 11B Rotating magnetic head 13 Switch 14 HPF 15 BPF 16 AFM trap section 17 Luminance signal reproduction processing section 19 Audio signal reproduction processing section 21 ATF trap section 22 LPF 24 Frequency conversion section 26 Crosstalk removal section 27 Variable de-emphasis section 28 Noise Reduction unit 35 Operation mode determination unit

Claims (4)

[Claims] 1. A recording luminance signal based on a luminance signal forming a video signal, a recording carrier color signal obtained by frequency-converting a carrier color signal forming the video signal to a low frequency side, and automatic tracking control. From a magnetic tape on which a composite recording signal including a pilot signal for recording is recorded, a magnetic head reads the composite recording signal to form a read composite signal, and a read composite signal obtained from the signal reading unit. A luminance signal reproducing circuit section for taking out a reading luminance signal and obtaining a reproducing luminance signal on the basis of the read reading luminance signal; and a trap section for reducing the amplitude of a pilot signal included in the read combined signal obtained from the signal reading section. A filter unit for extracting a read low-frequency conversion color signal from the read combined signal that has passed through the trap unit, and a read unit extracted by the filter unit. A frequency conversion unit for performing frequency conversion processing on the low-pass conversion color signal to obtain a reproduction carrier color signal; a de-emphasis unit for performing de-emphasis processing on the reproduction carrier color signal obtained from the frequency conversion unit; Is in the first state in which the composite recording signal is read from the magnetic tape in the normal reproduction operation mode, the trap section does not perform the amplitude reduction for the pilot signal, or the amplitude reduction for the pilot signal is performed. And the de-emphasis section is made smaller than the second state in which the signal reading section reads the composite recording signal from the magnetic tape under the variable speed reproduction operation mode. To
A video signal including an operation control unit that makes the degree of de-emphasis processing for the reproduced carrier color signal smaller than when the signal reading unit is in the second state. Playback device. 2. A de-emphasis section for switching the de-emphasis characteristic for the reproduced carrier color signal between when the signal reading section is in the first state and when the signal reading section is in the second state. The video signal reproducing apparatus according to claim 1, wherein: 3. The trap unit, the signal reading unit is the second unit.
The amplitude reduction for the pilot signal is performed in the state 1), and the amplitude reduction for the pilot signal is not performed when the signal reading unit is in the first state. Alternatively, the video signal reproducing device described in 2. 4. The trap unit, the signal reading unit is the first unit.
3. The video signal reproducing apparatus according to claim 1, wherein the amplitude reduction characteristic for the pilot signal is switched between the state of 1) and the state of the second state.