JPS6314585A - Magnetic recording and reproducing method and recorder - Google Patents

Abstract

PURPOSE:To discriminate the recording mode of a reproduced FM video signal by making the carrier frequency of two adjacent tracks different according to the recording mode. CONSTITUTION:The input video signal of a terminal 1 is supplied to the respective luminance signal recording processing circuits (circuit 2, 7, 8, 9) for a standard mode and (circuits 3, 10-12) for a high picture quality mode and a BPF4. The output of the BPF 4 is supplied to an adder 6 through a chrominance signal recording process processing circuit 5. A drum pulse is supplied to a terminal 13 for every one field of the video signal and fed to the addition circuits 8 and 11. Thereby, a preemphasis characteristic according to the recording mode is applied and the difference is obtained in the carrier frequency recorded on the adjacent tracks on a tape T. A frequency division multiplex signal is supplied to heads H1, H2 from the adder 6 and recorded on the adjacent tracks.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording/reproducing method and a recording device thereof, and particularly relates to a magnetic recording/reproducing method and a recording device thereof, and particularly to a method for recording video signals reproduced from a magnetic recording medium in either of two recording modes. The present invention relates to a magnetic recording/reproducing method and a recording device for the magnetic recording/reproducing method.

Conventional technology In recent years, tape performance and head performance have improved, and there is a demand for magnetic recording and reproducing devices with high resolution and high image quality.A high image quality mode in which the carrier frequency is shifted to a level sufficiently higher than the carrier frequency of current home VTRs has been developed. Various things are being considered.

Problems to be Solved by the Invention However, as mentioned above, there is no complete compatibility between signals recorded in recording modes with different carrier frequencies. The problem is that it cannot be played back. In order to solve this problem, it may be possible to provide a changeover switch or the like so that the user can operate the changeover switch arbitrarily, but this would allow the source (video signal) of the cassette 1- to be played back to be It is not possible to determine in which recording mode the video signal was recorded, and there are cases where video signals are recorded in different recording modes in the same cassette, which is not only extremely inconvenient to use, but also differs from the recording mode. There were problems such as the user might mistake the device for failure if the device is played back in this mode.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a magnetic recording and reproducing method that solves the above problems by making both carrier frequencies of frequency-modulated video signals recorded in 62 adjacent tracks different depending on the recording mode, and a recording method thereof. The purpose is to provide equipment.

Means for Solving the Problems The magnetic recording and reproducing method according to the present invention is characterized in that the carrier frequencies of frequency modulated video signals (FM video signals) are different from each other.
In one of the two recording modes, the carrier frequency f1 of the FM video signal recorded on one of the two adjacent tracks on the magnetic recording medium where the drum pulse is at a predetermined level is transferred to the other track. The frequency fi1 is higher than the carrier frequency f2 of the FM video signal recorded in
F is recorded on one of the two tracks mentioned above in the other recording mode.
The carrier frequency f3 of the M video signal is set to be lower than the carrier frequency f4 of the FM video signal recorded on the other track by a frequency fi2, and during reproduction, the carrier frequency f3 of the FM video signal recorded on the other track is set to the main 129 frequency of the reproduced FM video signal from the magnetic recording medium. The recording mode is determined based on the recording mode.

Further, in the magnetic recording device of the present invention, the carrier frequency f1 is set higher than f2 by a frequency fil, and
a first frequency modulation means for frequency modulating the video signal (FM modulation) in one of the two recording modes;
2, and select one of the output signals of the first and second frequency modulation means to perform FM modulation of the video signal according to the other recording mode. It consists of a recording means for recording on a recording medium.

Operation The frequencies fi1 and fi2 are both selected to be an odd multiple of 1/2 of the horizontal scanning frequency of the video signal.

Furthermore, since the carrier frequencies of the FM video signals recorded on two adjacent tracks are made to differ depending on the recording mode, the reproduced FMF from the magnetic recording medium is based on the carrier frequencies during reproduction. l! It is determined in which of the two recording modes the signal was recorded.

Embodiment FIG. 1 shows a block system diagram of an embodiment of a recording system of the magnetic recording and reproducing method according to the present invention. Before explaining this embodiment, first, frequency spectra of two recording modes will be explained with reference to FIG.

In this specification, the so-called II mode and high image quality mode will be explained as two recording modes.

In this case, the frequency spectrum of the frequency modulated luminance signal (FMM luminance signal) is shown in Fig. 4 in the above standard mode.
It becomes as shown in A, and in the above 3-stroke 'd mode, S is shown in the same figure.
As shown by e, the carrier frequency is set more closely than in the standard mode. In the frequency spectrum SA of the FM luminance signal shown in FIG. 4, fAS, fAP and fAW represent the carrier frequencies at the sync tip level, pedestal level and white peak level of the luminance signal, respectively;
Frequency spectrum SB, fBS, fBP and few
represent the carrier frequency at the sync tip level, pedestal level, and white peak level of the luminance signal, respectively. For example, in the standard mode, the carrier frequency fAS is 3.4MHz, fAP is 3.8MHz, fA
w is 4.4HH2, on the other hand, the above carrier frequency fss in high image quality mode is 5.0HH2, and f s p is 5
．． 6HH2, f'8w is 6,7M HZ.

By the way, in the current general home VTR, as disclosed in "Video Signal Recording Method and Apparatus" previously proposed by Mizu Applicant in Japanese Patent Publication No. 5818830, adjacent VTRs on a magnetic recording medium (magnetic tape) The difference in carrier frequency of the FM video signal recorded on the track is set to a frequency corresponding to an odd multiple of 1/2 of the horizontal scanning frequency that is in an interleaving relationship with the video signal. As a result, beat interference between adjacent tracks is reduced, and recording can be performed with fewer or no guard bands between each track, thereby increasing the efficiency of use of the magnetic recording medium.

The present invention makes use of the above-mentioned features of the VTR to perform recording by changing both carrier frequencies of FM video signals recorded on adjacent tracks depending on the recording mode, and during playback, mode discrimination is performed based on the carrier frequencies. It is characterized by the fact that it is designed to do this.

Next, an embodiment of the recording system of the method of the present invention will be explained with reference to FIG. In the figure, a video signal input to an input terminal 1 is filtered through a low-pass filter (LPF) and a comb filter 2.
3 and a bandpass filter (BPF) 4, respectively.

The BPF 4 converts the incoming video signal into a P-wave carrier color signal and outputs it to the color signal recording processing circuit 5 . The color signal recording processing circuit 5 converts the frequency of the carrier color signal into a low frequency converted carrier color signal and outputs it to the converter 6.

Here, LPF and comb filter 2. Pre1 emphasis circuit 7. Sieve 8. FM modulation: S') (For standard mode, LPF and comb filter 3° pre-emphasis circuit 10, numbing device 11, and FM modulator 12 each constitute a luminance Tσ signal recording processing circuit for high image quality mode. Input terminal 1 with the above LPF and comb filter 2.3
Both luminance signals obtained by converting the P-wave from the video signal are given pre-emphasis characteristics according to the recording mode in a pre-emphasis circuit 7.10, and then output to an adder 8.11.

On the other hand, the head 11. I2 is 180°
As the rotating head drum (not shown) installed oppositely rotates, one field fm of the video signal is high Level and D - Signal that repeats the level (
drum pulse) is supplied.

In this case, one frame of FM recorded on the magnetic tape T
FM video signal (CH,
) is recorded by head H1, and F of the next field is recorded by head H1.
It is assumed that an M video signal (CH2) is recorded by the head H2, and that the drum pulse is at a high level during the first one field period and at a low level during the next one field period. Furthermore, the level difference between the high level and low level of the drum pulse is, as will be described later, the difference in carrier frequency of the FM video signal recorded on mutually adjacent tracks formed on the magnetic tape T by the heads H+ and H2. The level is adjusted in advance so that the frequency fil or I12 is an odd multiple of 1/2 of the horizontal scanning frequency of the video signal.

The drum pulse is supplied to the ohm device 8, and the level is inverted via the inverter 14 before being supplied to the crimping device 11.

Adder 8 adds the output luminance signal of pre-emphasis circuit 7 and the drum pulse. The output addition signal of this cylinder 8 is frequency modulated in accordance with the standard mode by the FM modulator 9.
M modulation) is performed, and the terminal 15a of the switch circuit 15
supplied to

On the other hand, the adder 11 adds the output luminance signal of the pre-emphasis circuit 10 and the inverted drum pulse. The output addition signal of the adder 11 is subjected to FM modulation in accordance with the high image quality mode in the FM modulator 12, and the switch circuit 15
is supplied to terminal 15b of.

The switch circuit 15 is supplied via a terminal 16 with a mode switching signal corresponding to the recording mode set by a mode selection switch (not shown) or the like.

Here, when the recording mode is set to the F-semi-mode using the mode selection switch etc., the switch circuit 15 is switched to the terminal 15a side, and on the other hand, when the recording mode is set to the high image quality mode, the switch circuit 15 is switched to the terminal 15b side. It will be done.

In this way, the FM luminance signal is provided with a pre-emphasis characteristic according to the recording mode and subjected to FM modulation etc. according to the recording mode, and is outputted from the switch circuit 15 to the adder 6.

The adder 6 adds the FM luminance signal and the low-frequency conversion carrier color signal to obtain 1! ? Amplifier 17 records the frequency division multiplexed signal.
The signal is supplied to heads H+ and H2 via.

These heads H+ and H2 transmit the FM video signal (C
H+) and FM video signal (CH2) are recorded on the magnetic tape T by forming adjacent tracks. In this case, a small guard band or no guard band is provided between the tracks on which the FM video signals (C-1+) and (CH2) are recorded.

Also, in the standard mode, the F distributed by the head H1
The carrier frequency f1 of the M video signal (CH+) is FMI! recorded by the head H2. I! Image signal (CH
2) is set higher than the carrier frequency f2 by the frequency fiI, while in high image quality mode, the head]
111 of the FM video signal (CH,) recorded by '1
11 frequency f3 is higher than the main 119 frequency f4 of the FM video signal (CH2) recorded by head H2.
It is set lower by 2.

In this manner, in this embodiment, recording is performed with the carrier frequencies of the FM video signals recorded on adjacent tracks being made different depending on the recording mode.

Next, an embodiment of the reproducing system of the magnetic recording and reproducing method according to the present invention will be described with reference to FIG. In the same figure, head from magnetic tape T! ”+, FM played on H2 respectively
Video signals (CH+) and (CI-L) are preamplifier 2
1.22 to the terminals 23a, 23 of the switch circuit 23
b, respectively. The switch circuit 23 is switched in response to a head switching pulse input from the terminal 24, thereby obtaining a continuous reproduced FMI 211 image signal.

The output reproduced FM video signal of the switch circuit 23 is passed through a low-pass filter (LPF) 25 and a high-pass filter (+-IPF) 26.
are supplied respectively. L P F 25 is the incoming regeneration F
The low frequency converted carrier color signal is converted into a P wave from the M video signal and outputted to the color signal reproduction processing circuit 27. The color signal reproduction processing circuit 27 frequency-converts the incoming low-pass converted carrier color signal into a carrier color signal in the original frequency band, and outputs the frequency-converted carrier color signal to the adder 28 .

On the other hand, HPF26 comes in ■ Raw FMII! I! The reproduced FM luminance signal is converted into a P wave from the image signal and is applied to an equalizer circuit 29.
30 to a terminal 31a of the switch circuit 31.

31b. This equalizer circuit 29°30
are provided to provide equalizer characteristics corresponding to the standard mode and high image quality mode, respectively, to the incoming reproduced FM luminance signal.

Next, the output signal of the switch circuit 31 is supplied to FM demodulators 34, 35, and 36 via an automatic gain control circuit (AGC circuit) 32 and a limiter 33, respectively.

Here, the FM demodulator 34. LPF37. The de-emphasis circuit 38 and the arithmetic unit 39 are provided for the standard mode, and the reproduced luminance signal is obtained by performing FM demodulation and adding de-emphasis characteristics according to the standard mode to the output reproduced FM luminance signal of the limiter 33. is supplied to the pruner 39.

Similar to above, F~1 demodulator 35. The LPF 40° de-emphasis circuit 41 and the arithmetic unit 42 are provided for the high image quality mode, and provide FM demodulation and de-emphasis characteristics corresponding to the high image quality mode to the reproduced FM luminance signal output from the limiter 33. The reproduced luminance signal is supplied to the arithmetic unit 42.

On the other hand, a drum pulse a as shown in FIG.
9 and directly to calculation 2 (42). This drum pulse a corresponds to the inverted version of the drum pulse, and is an FM video signal (CH
+ ) playback period becomes [1- level, and head H
During the reproduction period of the FM video signal (CH2) by CH2, the high level roars.

In this case, the arithmetic unit 39 subtracts the inverted drum pulse a from the reproduced brightness signal output from the de-emphasis circuit 38, resulting in the original brightness at the same level as before entering the pre-emphasis circuit 7, adder 8, etc. The signal is restored and output to the terminal 45a of the switch circuit 45.

Similarly to the above, the de-emphasis circuit 41
Subtracting the drum pulse a from the output reproduction luminance signal of
Eventually, the original luminance signal at the same level as before entering the pre-emphasis circuit 10, the sigma adder 11, etc. is restored and output to the terminal 45b of the switch circuit 45.

On the other hand, the FM demodulator 36. LPF46. Sample and hold circuit 47.48. Inverter 49. Monostable multivibrator50.51. A comparator 52 and a system controller 53 are provided for mode discrimination, and after the reproduced FM luminance signal output from the limiter 33 is FM demodulated by an FM demodulator 36, the cutoff frequency is set to 1kHz, for example.
The horizontal synchronizing signal is removed by a 7-filtration LPF 46 and supplied to sample and hold circuits 47 and 48, respectively.

Further, the drum pulse a is supplied to a monostable multivibrator 50 via an inverter 49, and is also supplied to a direct stable multivibrator 51. As a result, the monostable multivibrator 50 as shown in FIG. 3 (B
), a zumbling pulse b that rises at the falling time of the drum pulse a is generated and output to the sample hold circuit 47. On the other hand, the thousand-stable multivibrator 51 generates four non-pulling pulses C that rise at the pulse rise time of the drum pulse a and outputs them to the sample hold circuit 48, as shown in FIG. 3(C).

Here, the zumbling pulses b and C are the head H1.
The level changes depending on the picture pattern in the reproduced FM video signal (CHl) by the head H2 and the reproduced FM video signal (Clt2) by the head H2. are the reproduction rXi degree and l\ by head H1 respectively.
Sample and hold the DC value during the vertical blanking period of the reproduced luminance signal by RAD2.

The output signals 8V1 and V2 of the ripple hold circuits 47 and 48 are respectively supplied to the non-inverting input terminal and the inverting input 9i of the comparator 52. The comparator 52 compares the incoming signals v1 and 2, and outputs a signal to the system controller 53 that becomes high level if Vl > V2, and becomes low level if Vl < V2.

The system controller 53 receives the incoming comparator 52
If the output signal of the comparator 52 is at a high level, the recording mode of the reproduced video signal is the standard mode, and on the other hand, if the output signal of the comparator 52 is a low level, the recording mode of the reproduced video signal is the high quality mode. The switch circuit 3 generates a mode discrimination signal according to the mode discrimination result.
1 and 45, respectively, and these are switched and controlled.

In this case, if the recording mode is determined to be the standard mode by the system controller 53, the switch circuits 31 and 45 are connected to the terminals 31a and 45a, respectively;
When the recording mode is determined to be the high image quality mode, the switch circuits 31 and 45 are connected to the terminals 31b and 45b, respectively. As a result, the reproduced FM luminance signal is subjected to FM demodulation according to the recording mode, imparted with equalizer characteristics and de-emphasis characteristics, and restored to the original luminance signal level.

Thereafter, the adder 28 adds 1q to the output reproduction ilG of the color signal reproduction processing circuit 27 and the output reproduction luminance signal of the color/date signal switch circuit 45 and outputs a reproduced video signal to the output terminal 54.

In the embodiments shown in FIGS. 1 and 2, mode discrimination is performed by using drum pulses to vary the carrier frequency of FM video signals recorded on adjacent tracks depending on the recording mode. However, the method of varying the carrier frequency in this way is not limited to this embodiment. For example, as disclosed in the above-mentioned Japanese Patent Publication No. 18830/1983, the luminance signal may be frequency-converted after being tuned to FM9. It's okay. In addition, the FM demodulator 36 and LP in FIG.
F46 may be omitted and the output reproduced luminance signal of the LPF 40 for high image quality mode may be supplied to the sample and hold circuits 47 and 48.

Effects of the Invention As described above, according to the present invention, the carrier frequencies of the FM video signals recorded on two adjacent tracks are made different depending on the recording mode, so that the carrier frequencies can be detected. This allows for reliable mode discrimination and
It is easy to perform, and there is no need for the complicated switching operation of operating a changeover switch as in the past.
It is very easy to use for the sound being used, and it also prevents the sound from being played back in a mode different from the recording mode, which prevents the user from misinterpreting it as a malfunction. It has the advantage that the method and apparatus of the present invention can be realized at low cost by adding a simple circuit configuration with almost no changes.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are block diagrams showing an embodiment of a recording system and a reproducing system of the magnetic recording and reproducing method according to the present invention, respectively;
3A to 3C are signal waveform diagrams for explaining the operation of the block system shown in FIG. 2, and FIG. 4 is a frequency spectrum diagram of the FM luminance signal in the standard mode and high image quality mode. 1...Video signal input terminal, 8.11...Additional f3 device,
13.43...Drum pulse input terminal, 14,44°49...Inverter, 36...FM demodulator, three. 42... Arithmetic unit, 46... Low pass filter (LPF)
, 47.48...sample hold circuit, 50.51
... Monostable multivibrator, 52... Comparator, 53... System controller, 54... Playback video signal output terminal, H+, H2... Head, T.
··Magnetic tape.

Claims (2)

[Claims] (1) When recording a video signal in one of two recording modes in which the carrier frequency of the frequency-modulated video signal is different from each other, the drum pulse of two adjacent tracks on the magnetic recording medium The carrier frequency f_1 of the frequency-modulated video signal is recorded on one track during the period when the frequency-modulated video signal is at a predetermined level, and the carrier frequency f_1 of the frequency-modulated video signal is recorded on the other track.
A frequency fi_ corresponding to an odd multiple of 1/2 of the horizontal scanning frequency of the video signal within substantially the same frequency band as _2.
1, and when recording a video signal in the other recording mode of the two recording modes, the drum pulse of two adjacent tracks on the magnetic recording medium is set to the predetermined value. The carrier frequency f_3 of the frequency modulated video signal is recorded on one track formed in a certain period at the same level, and the carrier frequency f_4 of the frequency modulated video signal recorded on the other track is within the same frequency band as that video signal. The frequency is set low by a frequency fi_2 corresponding to an odd multiple of 1/2 of the horizontal scanning frequency of the magnetic recording medium. A magnetic recording and reproducing method characterized in that it is configured to determine in which of the two recording modes a signal was recorded. (2) Of the two adjacent tracks on the magnetic recording medium, the carrier frequency f_1 of the frequency-modulated video signal is recorded on the other track, which is formed during the period when the drum pulse is at a predetermined level. The frequency fi_1 corresponding to an odd multiple of 1/2 of the horizontal scanning frequency of the video signal is set higher than the carrier frequency f_2 of the frequency modulated video signal in substantially the same frequency band, and a first frequency modulation means for frequency modulating a video signal in one of two recording modes having different carrier frequencies; One track formed during a certain period at a predetermined level has a carrier frequency f_3 of a frequency-modulated video signal recorded on the other track, and a carrier frequency f_4 of a frequency-modulated video signal recorded on the other track. a second frequency modulation means that sets a frequency fi_2 lower, which corresponds to an odd multiple of 1/2 of the horizontal scanning frequency of the signal, and frequency-modulates the video signal by the other recording mode of the two recording modes; , the first
and recording means for selecting either one of the two output signals of the second frequency modulation means and recording it on the magnetic recording medium.