JP3533794B2 - Magnetic recording medium processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium processing apparatus. Specifically, at the time of signal recording, a magnetic head having a first gap portion and a second gap portion having a longer gap length than the first gap portion at an end of the first gap portion has a lower frequency than a recording signal. A magnetic head in which a low-frequency signal is recorded, and the signal is processed after attenuating the low-frequency signal during signal reproduction, so that the gap width of the first gap portion is smaller than the track width of the already recorded signal. Even if the signal is rewritten using
A good reproduced signal can be obtained. 2. Description of the Related Art In a conventional magnetic recording medium processing apparatus, for example, a video tape recorder, a rotating magnetic head is used to record a time code, a date, or a picture on a tilted recording track of a magnetic tape together with a video signal and an audio signal. A data signal indicating information such as the aspect ratio of the data can be recorded. In such a video tape recorder, not only a signal is recorded by using a rotating magnetic head having a signal recording width corresponding to a standard recording track width, but also the recording track width is narrowed and the track is recorded. In some cases, a rotating magnetic head having a smaller signal recording width than a standard recording track width is used so that a guard band is provided between tracks to reduce crosstalk from an adjacent track. Also, in order to use different recording modes such as the standard time recording mode and the long time recording mode by using a single video tape recorder, a rotating magnetic recording medium having a signal recording width narrower than the standard recording track width. A head may be used. FIG. 6 shows a tape pattern of, for example, an 8 mm video system. In FIG. 6, an inclined track TS is generated at the center of the magnetic tape 1 by a rotating magnetic head. A multiplex signal VAW obtained by frequency-multiplexing an FM-modulated luminance signal, a low-frequency-converted carrier chrominance signal, and an FM-modulated audio signal is recorded in the area TVA of the inclined track TS. A data signal DTW is recorded in an area TSC, and a digital audio signal DAW is recorded in an area TDA. In an 8 mm video apparatus, audio signals and control signals can be recorded on both sides of a magnetic tape by fixed heads as in an optional standard, similarly to a 1/2 inch video tape recorder. In this case, for example, an audio track (longitudinal track) TA on which an analog audio signal is recorded by a fixed head is generated at one end of the magnetic tape 1. At the other end of the magnetic tape 1, a control track (longitudinal track) TC on which a control signal is recorded by a fixed head.
Is generated. In a camera-integrated 8 mm video tape recorder, the signal recording width of the rotary magnetic head is set to a tilted track T.
A rotating magnetic head (hereinafter, referred to as “standard head”) corresponding to the standard track width of S (20.5 μm) is used,
In a stationary 8 mm video tape recorder, the signal recording width, that is, the gap width is smaller than the standard track width (for example, 15 μm) so that a common rotating magnetic head can be used in the standard time recording mode and the long time recording mode. A head (hereinafter, referred to as a “narrow head”) is used. A data signal DTW of a magnetic tape in which signals are recorded with a standard track width by a camera-integrated 8 mm video tape recorder, for example, is used.
In the case of rewriting using a stationary 8 mm video tape recorder, since the stationary 8 mm video tape recorder has a narrow head, a part of the signal recorded by the standard head remains on the track without being rewritten. I will. For this reason, when the magnetic tape 1 in which a part of the signal is not rewritten is reproduced by using the standard head, the interference of the non-rewritten signal causes deterioration of the signal-to-noise ratio. . Further, the magnetic field generated by increasing the recording current supplied to the narrow head is made strong, and all the signals recorded by the standard head are rewritten using the magnetic field generated on both sides of the gap of the head. In such a case, the narrow head is magnetized by an excessive recording current, and it becomes impossible to correctly record a signal. In view of the above, the present invention provides a magnetic recording medium processing apparatus capable of performing a good signal rewriting process even when a magnetic head having a signal recording width smaller than the track width of a recorded signal is used. . According to the present invention, there is provided a magnetic recording medium processing apparatus comprising: a first gap portion; and an end of the first gap portion having a gap length longer than the first gap portion. A second gap portion having a large width;
The inclination of the center line of the angle formed by
A magnetic head set so as not to match, a signal generating means for generating a low frequency signal lower in frequency than the recording signal,
A signal supply unit that adds the recording signal and the low-frequency signal and supplies the resultant signal to the magnetic head; and a frequency band limiting unit.
When the recording signal and low-frequency signal are recorded in the gap,
The low-frequency signal is recorded in the second gap,
From the reproduced signal obtained by regenerating the body,
The step attenuates low frequency components . In the present invention, a recording signal and a low-frequency signal are recorded on the magnetic recording medium in the first gap portion of the magnetic head, and both sides of an area where the recording signal and the low-frequency signal are recorded. The low frequency signal is recorded in the second gap portion. Further, the low frequency signal component is attenuated from the reproduced signal obtained by reproducing the magnetic recording medium on which the signal is recorded, and only the frequency component of the recorded signal is extracted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic recording medium processing apparatus according to the present invention will be described below with reference to FIG. In FIG. 1, an input video signal VIN is supplied to a video recording signal generator 11. Video recording signal generator 1
In step 1, the luminance signal of the input video signal VIN is FM-modulated and the carrier chrominance signal is low-frequency-converted, and the video recording signal VW is generated from the FM-modulated luminance signal and the low-frequency-converted carrier chrominance signal. This video recording signal VW is supplied to the multiplex processing unit 14. The input audio signal AIN is supplied to an audio recording signal generator 12 and a digital audio recording signal generator 13. In the audio recording signal generation unit 12, the input audio signal AIN is FM-modulated to be an audio recording signal AW. This audio recording signal AW is supplied to the multiplex processing unit 14. In the digital audio recording signal generator 13, the input audio signal AIN is pulse-coded and modulated to generate a digital audio signal DAW. The digital audio signal DAW is supplied to the time division processing unit 16. The data signal generator 15 generates a data signal DTW indicating information such as time code and date.
This data signal DTW is supplied to the time division processing unit 16. In the multiplex processing section 14, the video recording signal VW and the audio recording signal AW are frequency-multiplexed to generate a multiplex signal VAW. The multiplex signal VAW is supplied to the time division processing unit 20. The time division processing unit 16 includes a control unit 1 to be described later.
0 based on the control signal CS from 0.
W or data signal DTW is selected to generate digital recording signal ATW. That is, the digital audio signal DAW is selected when the rotary magnetic head for recording (hereinafter referred to as “recording head”) is located in the area TDA of the magnetic tape 1 shown in FIG. The signal DTW is selected, and the digital recording signal ATW is generated. The digital recording signal ATW is supplied to the multiplex processing unit 19. The low-frequency signal generating section 17 as a signal generating means generates a low-frequency signal SLW having a lower frequency than the digital audio signal DAW and a lower frequency than the data signal DTW. This low frequency signal SLW
Is supplied to the multiplex processing unit 19 via the switch 18. The switch 18, the multiplex processing unit 19, and a time division processing unit 20 and a signal switching unit 22 described later constitute a signal supply unit. The switch 18 is controlled based on a control signal CS from the control unit 10, and is turned on only when the signal is rewritten and recorded in the area TSC or the area TDA of the magnetic tape 1 shown in FIG. In the multiplex processing section 19, the digital recording signal ATW and the low-frequency signal SLW are frequency-multiplexed and the multiplexed signal A
TLW is generated. The multiplex signal ATLW is supplied to the time division processing unit 20. In the time division processing section 20, when the recording head is located in the areas TDA and TSC of the magnetic tape 1 based on the control signal CS from the control section 10, the multiplex signal ATLW is selected and located in the area TVA. In this case, the multiplex signal VAW is selected. The selected multiplex signals ATLW and VAW are supplied to the signal switching unit 22 via the recording amplifier 21.
The signal switching section 22 controls the supply of the multiplex signals ATLW and VAW to the recording heads 7a and 7b provided on the drum 5. The recording heads 7a and 7b are narrow heads whose signal recording width is smaller than the standard track width.
As shown in FIG. 2, the gap portions of the recording heads 7a and 7b have the configuration shown in FIG. 2B. As shown in FIG. 2B, the gap width HW of the first gap portion of the recording heads 7a and 7b is formed smaller than the standard track width TW. The gap length GH of the first gap portion is suitable for recording the digital recording signal ATW and is shorter than the wavelength of the low frequency signal SLW. Here, the multiplex signal ATLW is transmitted to the recording head 7.
a and 7b, a magnetic field is generated in the first gap portion with a width substantially equal to the gap width HW based on the digital recording signal ATW and the low frequency signal SLW. The gap length GL of the second gap portion on both ends of the first gap portion is longer than the wavelength of the digital recording signal ATW.
Since the wavelength is equal to or shorter than the wavelength of the low frequency signal SLW, a magnetic field based on the low frequency signal SLW is generated in the second gap. Therefore, as shown in FIG. 2C, the digital recording signal ATW and the low-frequency signal SLW are recorded on the inclined track TS of the magnetic tape 1 in an area having a width smaller than the standard track width TW, and on both sides of this area. Only the low frequency signal SLW is recorded. The recording heads 7a and 7b may be metal heads having a high magnetic permeability film attached to the gap surface. The rotation of the drum 5 and the driving of the magnetic tape 1 are performed by a drive unit 9, which is controlled by a drive signal DR from a control unit 10. Further, a head switching pulse signal HP is supplied from the driving unit 9 to the control unit 10. The control unit 10 includes a synchronization separation unit (not shown)
Supplies a synchronizing signal SY separated from an input video signal VIN or a video signal obtained during reproduction of the magnetic tape 1 as described later, and a control signal CS is generated based on the synchronizing signal SY. Further, the drive signal DR is generated based on the head switching pulse signal HP and the synchronization signal SY such that the phase of the drum 5 becomes a predetermined phase. A signal obtained when the magnetic tape 1 is reproduced by using a reproducing rotary magnetic head (hereinafter referred to as "reproducing head") 8a, 8b is supplied to a signal switching section 22.
In the reproducing heads 8a and 8b, the video recording signal VW and the audio recording signal AW of the multiplex signal VAW and the multiplex signal ATL
The W digital recording signal ATW and the low frequency signal SLW are reproduced. The signal switching section 22 alternately selects signals supplied from the reproducing heads 8a and 8b to generate a reproduced signal RS. The reproduced signal RS is supplied to a video signal reproducing unit 32, an audio signal reproducing unit 33, and a low frequency signal removing unit 34 as a frequency band limiting unit via a reproducing amplifier 31. In the video signal reproducing section 32, the luminance signal component of the reproduced signal RS is FM-demodulated, and the chrominance signal component is frequency-high-converted. Further, a video signal is generated based on the luminance signal obtained by the FM demodulation and the color signal obtained by the frequency high-frequency conversion, and this video signal is output video signal VOU.
Output as T. In the audio signal reproduction unit 33, the audio signal component of the reproduction signal RS is FM-demodulated and output as an output audio signal AOUT. The low-frequency signal removing section 34 is constituted by using a high-pass filter or the like, and has the characteristics shown in FIG. In FIG. 3, the horizontal axis represents frequency, and the vertical axis represents signal level. The low frequency signal component of the reproduction signal RS indicated by the broken line A is attenuated by the low frequency signal removing unit 34,
Only the digital recording signal component of the reproduction signal RS indicated by the broken line B is output from the low frequency signal removing section 34. The signal output from the low frequency signal remover 34 is supplied to a digital audio signal reproducer 35 and a data signal reproducer 35. Digital audio signal reproducing unit 35
Then, the supplied signal is decoded into a digital audio signal. This audio signal is output as an output audio signal ADOUT. In the data signal reproducing unit 36, the supplied signal is processed to be a data signal. This data signal is output as an output data signal DOUT.
On the basis of the output data signal DOUT, information such as a time code and a date is displayed. Next, the operation will be described. For example, when rewriting a data signal or a digital audio signal recorded in the areas TSC and TDA of the magnetic tape 1 with the standard track width TW, the switch 18 shown in FIG. 1 is turned on, and the low frequency signal ALW is added to the digital recording signal ATW. Are multiplexed.
The multiplex signal ATLW is supplied to the recording heads 7a and 7b at the timing when the recording heads 7a and 7b scan the areas TSC and TDA of the magnetic tape 1. The recording heads 7a and 7b generate a magnetic field based on the digital recording signal ATW and the low frequency signal SLW in the first gap portion smaller than the standard track width TW, and generate the low frequency signal in the second gap portion. A magnetic field is generated based on the signal SLW. For this reason, as shown in FIG. 4, in an area TSC in which a data signal is recorded and in an area TDA in which a digital audio signal is recorded, an added signal of the digital recording signal ATW and the low frequency signal SLW is recorded at the center of the track. And a low frequency signal SL on both sides of the track.
W is recorded. Also, as described above, the digital recording signal AT
When the magnetic tape 1 on which W and the low-frequency signal SLW are recorded is reproduced using the reproducing heads 8a and 8b, the reproduced signal is supplied to the low-frequency signal removing unit 34, and the frequency component of the low-frequency signal SLW is attenuated. Therefore, a rewritten output digital audio signal or data signal can be obtained without being affected by the low frequency signal SLW. As described above, according to the above-described embodiment,
For example, when rewriting a data signal with a recording head having a gap width smaller than the standard track width, a new signal is recorded at the center of the inclined track, and a low-frequency signal is recorded on both sides of the inclined track. , The entire track width is rewritten. When a magnetic tape whose signal has been rewritten is reproduced by a recording head having a head width smaller than the standard track width, a low-frequency signal is removed from the reproduced signal and processed. Therefore, even if a magnetic head narrower than the standard track width is used, the signal can be rewritten without deteriorating the signal-to-noise ratio. In the meantime, the low-frequency signal generator 17 generates the low-frequency signal SLW using an oscillator. However, in an 8-mm video tape recorder, a pilot signal is superimposed on a video signal for tracking control. Therefore, the low frequency signal SLW may be generated by dividing the frequency of the reference signal for generating the pilot signal. Further, the control unit 10 divides the frequency of a clock signal for performing a control operation, or uses a carrier of a video signal obtained by reproducing the magnetic tape 1 with the reproducing heads 8a and 8b during a recording operation to reduce the frequency. If the signal SLW is generated, there is no need to provide the low-frequency signal generator 17 and the configuration can be simplified. If the digital recording signal ATW is recorded and encoded and processed, low-frequency components and high-frequency components are reduced in the recorded and encoded digital recording signal ATW. For this reason, the recording / reproducing characteristics in magnetic recording, that is, the matching between the characteristics and the recording / reproducing characteristics in which the signal level is reduced in the low frequency region (the region where the frequency is lower than the low frequency signal SLW) and in the high frequency region and which is formed into a mountain shape are improved. By improving the recording density, the recording density can be increased. Thus, the digital recording signal ATW
In the case where the signal is recorded and coded, the signal can be rewritten by using the low frequency signal SLW without deteriorating the signal-to-noise ratio. The recording heads 7a and 7b are not limited to those having the configuration shown in FIG. For example, as shown in FIG. 5A, the first gap
And the second gap portion may be formed, and as shown in FIG. 5B, the first gap portion and the second gap portion may be formed by forming the ends of the gap surface in an inclined manner. It may be formed. In the case shown in FIG. 5A, in the recording method using azimuth loss, the inclination of the center line of the angle α formed by the gap surface of the second gap portion of one recording head has an azimuth loss effect on an adjacent track recording signal. In order not to reduce the azimuth angle, the azimuth angle is set so as not to coincide with the azimuth angle of the other recording head. In the above-described embodiment, the description has been given of the case where the recording head and the reproducing head are separately provided. However, a video tape recorder which shares the recording head and the reproducing head may be used. Furthermore, although the signal of the inclined track of the video tape recorder is rewritten, it is needless to say that the present invention can be applied not only to the inclined track of the video tape recorder but also to a magnetic disk device or the like. According to the present invention, when recording a signal,
The recording signal and the low frequency signal are recorded on the magnetic recording medium in the first gap portion of the magnetic head, and the low frequency signal is recorded in the second gap portion on both sides of the area where the recording signal and the low frequency signal are recorded. Is recorded. When reproducing a signal, a low-frequency signal component is attenuated from a reproduced signal obtained by reproducing a magnetic recording medium, and only a frequency component of a recording signal is extracted. Therefore, even when a signal having a standard track width is rewritten by a recording head in which the gap width of the first gap portion is smaller than the standard track width of the magnetic recording medium,
A new signal is recorded in the center, and a low-frequency signal is recorded in the second gap on both sides of the track.
All signals of the track width are rewritten. When a signal recorded on a magnetic recording medium is reproduced, the low-frequency signal is removed from the reproduced signal, so that the signal can be rewritten without deteriorating the signal-to-noise ratio or the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of an embodiment of a magnetic recording medium processing apparatus according to the present invention. FIG. 2 is a diagram illustrating a configuration of a recording head. FIG. 3 is a diagram illustrating characteristics of a low-frequency signal removing unit 34; FIG. 4 is a diagram showing an operation of the embodiment. FIG. 5 is a diagram showing another configuration of the gap portion. FIG. 6 is a diagram showing a tape format. [Description of Signs] 1 Magnetic tape 5 Drum 7a, 7b Recording head 8a, 8b Reproducing head 9 Drive unit 10 Control unit 11 Video recording signal generation unit 12 Audio recording signal generation unit 13 Digital audio recording signal generation unit 14, 19 Multiplex processing Unit 15 data signal generation unit 16, 20 time division processing unit 17 low frequency signal generation unit 18 switch 21 recording amplifier 22 signal switching unit 31 reproduction amplifier 32 video signal reproduction unit 33 audio signal reproduction unit 34 low frequency signal removal unit 35 digital audio Signal reproducing unit 36 Data signal reproducing unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 5/00-5/027 G11B 5/09

Claims (1)

(57) [Claim 1] A first gap portion and a second gap portion having a wider gap length than the first gap portion at an end of the first gap portion. The gap of the second gap portion.
The inclination of the center line of the angle formed by the plane coincides with the other azimuth angle
A magnetic head set so as not to be generated, a signal generating means for generating a low frequency signal having a lower frequency than the recording signal, a signal supplying means for adding the recording signal and the low frequency signal and supplying the added signal to the magnetic head, Frequency band limiting means, wherein the recording signal and the low-frequency signal in the first gap portion
Is recorded, and the low gap is recorded at the second gap portion.
Wave signal is recorded, and the reproduced signal is obtained by reproducing the recording medium.
From the raw signal, the low frequency
A magnetic recording medium processing device characterized by attenuating wave components .