JPH0364944B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a control signal for recording a control signal that is a reference signal indicating the position of a video track on a magnetic tape, used in a helical scan type magnetic recording and reproducing device. Regarding recording methods.

(Prior Art) FIG. 1 is a diagram showing the recording state of a conventional recorded magnetic tape used in a helical scan type magnetic recording and reproducing apparatus.

FIG. 2 is a timing chart showing the waveforms of control signals used in the prior art and the present invention; FIG. 2A is a timing chart showing the waveform of control signal 3; FIG. FIG. 3 is a diagram showing signal waveforms for explaining the invention.

A control signal 3, which is a reference signal indicating the position of a video track 2 on a magnetic tape 1, is sequentially magnetically recorded as a pattern of north pole and south pole on a control track 4 as a square wave of a magnetic tape saturation recording device.

In addition, in video track 2, the video signal, PCM
The converted audio signals and the like are recorded. In the following explanation, these signals recorded on the video track will be referred to as video signals.

Here, a contact transfer method will be considered as a magnetic tape duplication method.

This duplication method involves overlapping a master tape and a slave tape with their magnetic surfaces and winding them onto the same reel, and then applying a bias magnetic field from above the overlap to make the child tape become the parent tape. This is a reproduction method that magnetically transfers recorded signals on tape.

A bias magnetic field is applied to the parent tape and child tape while they are layered and wound on a reel, so that the long wavelength signal magnetic field of the parent tape is transferred to the magnetic surface of the child tape to be transferred. , so-called interlayer transfer occurs, in which the long wavelength signal of the parent tape is transmitted through this magnetic surface and transferred to other magnetic surfaces of the child tape.

The magnitude of interlayer transfer (LS) is approximately expressed by the following equation.

Ls = -54.6d/λ (dB) where d is the interlayer distance (the sum of the thickness of the parent tape and the thickness of the child tape), and λ is the recording signal wavelength of the parent tape.

Therefore, during magnetic transfer, long-wavelength recording signals on the parent tape are more likely to be transferred between layers.

That is, it is widely used in helical scan type magnetic recording and reproducing devices. For example, if you compare the wavelength of the control signal 3, which is a 30Hz square wave signal, with the wavelength of the video signal, which is several hundred KHz to several MHz recorded on the video track 2, the control signal is larger than the video signal. Since the wavelength is extremely long, interlayer transfer is more likely to occur in the control signal 3 than in the video signal 5 during magnetic transfer.

When this was calculated for the control signal, the difference between the two was approximately several dB, and the amount of interlayer transfer was not negligible.

(Object of the Invention) The present invention is a control signal recording method that is compatible with conventional recorded magnetic tapes, and which uses a control signal having a recording wavelength shorter than the recording wavelength of the conventionally used control signal. The object of the present invention is to provide a control signal recording method that can extremely reduce interlayer transfer during magnetic transfer.

Further, the present invention is a control signal recording method that is compatible with conventional recorded magnetic tapes, has a recording wavelength shorter than the recording wavelength of conventionally used control signals, and has The object of the present invention is to provide a signal recording method that improves the utilization efficiency of magnetic tape by recording a signal different from the control signal on the magnetic tape, thereby making it possible to record other information using the control track. It is.

(Structure of the Invention) (1) In a control signal recording method for recording a control signal, which is a reference signal indicating the position of a video track of a magnetic tape, on a control track of a magnetic tape, the method is used in a helical scan type magnetic recording/reproducing device. One period of the control signal includes a non-magnetized non-signal section having a non-magnetized signal level, and first and second magnetized sections adjacent to the non-signal section and having signal levels of opposite polarity, which are used as position references for the video track. 1. A control signal recording method, characterized in that the recording wavelength recorded on the control track of the control signal is shorter than the period of the control signal.

(2) A control signal recording method for recording a control signal, which is a reference signal indicating the position of a video track on a magnetic tape, on a control track of a magnetic tape used in a helical scan type magnetic recording/reproducing device, the control signal being One period consists of a no-signal section having a no-signal level that is not magnetized, and first and second magnetized sections that are used as a position reference of the video track and are adjacent to the no-signal section and have signal levels of opposite polarity. In the control signal recording method, the recording wavelength recorded on the control track of the control signal is shorter than the cycle of the control signal, wherein the first and second magnetization sections are within the no-signal section of the control signal. A control signal recording method characterized in that a signal different from the control signal is interposed and recorded by providing a magnetization section in which magnetization reversal occurs in a direction opposite to the magnetization reversal in the control signal.

(Example) The present invention is a control signal recording method using a control signal having a shorter recording wavelength than the recording wavelength of a conventionally used control signal,
Further, the present invention is a control signal recording method for recording a signal having a recording wavelength shorter than the recording wavelength of a conventional control signal and different from the control signal.

The control signals used in the present invention are such that the magnetic tape recorded using the signal recording method of the present invention is compatible with conventional recorded magnetic tape.
This is a signal with the same period as the frequency of a conventional control signal.

FIG. 3 is a diagram showing a recorded magnetic tape on which the control signal 5 shown in FIG. 2B is recorded.

FIG. 4 is a diagram showing a recorded magnetic tape on which the reproduction control signal 7 shown in FIG. 2C is reproduced.

One period T of the control signal 3 shown in FIG. 2A
consists of two sections, section A and section B.

Control signal 5 (7) 1 used in the present invention
The period T is a section (first magnetization section) that is used as a position reference of the video track and has a signal level of
A ₁ (A ₂ ), a section (second magnetized section) B ₁ (B ₂ ) which is used as a position reference of the video track and has a signal level of , a no-signal section C (C ₁ , It consists of three sections: C ₂ ).

Section A in each control signal 3, 5, 7,
A ₁ and A ₂ are sections in which the control tracks 4, 6, and 8 are respectively magnetized to N poles.

Control signal 5 (7) has a no-signal interval C (C ₁ , C ₂ ) that control signal 3 does not have.

The period of control signal 5 (7) is the same as the synchronization of control signal 3, and the rise of section A ₁ (A ₂ ) of control signal 5 (7) is completely synchronized with the rise of section A of control signal 3. ing.

The falling edge of section _B2 of the reproduction control signal 7 is completely synchronized with the falling edge of section A of the control signal 3.

The interval A ₁ (A ₂ ) of the control signal 5 (7), that is, the interval in which the control tracks 6 and 8 are magnetized to the north pole, is shorter than the interval A of the control signal 3.

In the control track 6 (8), the section A ₁ (A ₂ ) of the control signal 5 (7) is a N-pole pattern, the section B ₁ (B ₂ ) is an S-pole pattern, and the no-signal section C (C ₁ , C ₂ ) portions are sequentially formed corresponding to the no-signal patterns.

The length of the no-signal pattern on the magnetic tape 1 is longer than the N-pole pattern and the S-pole pattern.

As described above, the control signal used in the present invention has the same frequency as the conventional control signal, and the recording wavelength recorded on the magnetic tape is shorter than the recording wavelength of the conventional control signal. Therefore, a magnetic tape recorded using conventional control signals can be reproduced using a recording/reproducing apparatus using the signal recording method of the present invention,
During magnetic transfer, conventional control pulses can be used to perform magnetic transfer with less interlayer transfer compared to magnetic tape.

Next, another aspect of the present invention will be explained.

This invention is a signal recording method using a control signal in which a data signal is inserted into the control signal used in the invention described above.

Of course, it goes without saying that this control signal is also compatible with playback devices that perform recording and playback using control signals 3, 5, and 7.

Figure 2D shows control signal 1 used in the present invention.
Indicates 0.

The control signal 10 is a control signal having a control signal which is a reference signal indicating the position of a video track and a data signal which will be described later.

In the control signal 10, information as a control signal which is a reference signal indicating the position of the video track on the magnetic tape is contained in the control signal 3.
The data signal is included in section _A3 synchronized with the rising edge of section A, and the data signal is recorded as the length _A4 (or _A5 ) of the distance from the rising edge of section _A3 .

As shown in Figure 2D, when the data signal is "0", the period of the control signal is as shown in section _A4 .
35% (0.35T), and when the data signal is "1", it becomes 65% (0.65T) as in section _A5 .

In this way, the control signal 10 has a duty cycle of approximately 50, whereas the control signal ₃ has a duty cycle of "1" depending on the data signal included in the control signal 10. , is a control signal in which a signal of "0" is inserted.

FIG. 2E shows the reproduced signal 11 when the control signal 10 is reproduced.

As shown in the figure, the section of the control signal 10
The part of the reproduced signal 11 corresponding to A ₃ is A ₆ ,
This _A6 is determined as a control signal using the determination level D. The portion exceeding level D is determined as a control signal.

In _other words _, as shown in FIG _{. 2D} and _E , magnetization reversal ( _reproduction signal part _A6 ,
A data signal is interposed and recorded by providing a magnetization section in which the magnetization is reversed in the opposite direction (corresponding to the reproduced signal portions _{A 7 and} A ₈ ).

The result of determining the control signal is shown in Figure 2 F.
A reproduction control signal 12 as shown in FIG. 1 is obtained.

The discrimination level D is appropriately set so as to be set above the unnecessary pulse _A7 .

The portion of the reproduced signal 11 corresponding to the data signal (A ₄ , A ₅ ) in which signals of “1” and “0” are recorded as the length of the distance from the rising edge of section A ₃ of the control signal 10 is A ₈ , A ₉ .

These A ₈ and A ₉ are determined as data signals using the determination level E. The portion exceeding level E is determined as a data signal.

As a result of determining the data signal, a reproduced signal 13 as shown in FIG. 2G is obtained.

The discrimination level E is appropriately set to be lower than the unnecessary pulse _A10 .

Since the level E is at the opposite position to the level D via the reproduced signal 11, when the control signal and the data signal are picked up separately from the reproduced signal 11, the two signals are not mixed and discriminated.

FIG. 2H shows the output signal 14 of a multivibrator (not shown) which is output with a predetermined pulse width in synchronization with the rise of the reproduction control signal 12.
The rise of the main signal 14 is the control signal 10
It is synchronized with the rise of section _A3 .

As shown in FIG. 2I, playback control signal 1
The gate signal 15 is a signal obtained by delaying A ₆ of No. 2 by an arbitrary time and forming an arbitrary pulse width A ₁₁ .

In order to determine whether the data signal is "0" or "1", the pulse width A ₁₁ of the gate signal 15 is
Use.

That is, the data signal can be extracted by ANDing the gate signal 15 and a signal obtained by inverting the reproduced signal 13.

In this method, as shown in _FIG .
If _A8 is not inserted, the data signal is set to “0”.
When the part _A9 of the reproduced signal 13 is included in _A11 , the data signal is determined to be "1" and the data signal in the control signal 10 is extracted.

The data signal within the control signal 10 is the fifth
As shown in the figure, it is a 32-bit serial data signal 16.

The data signal 16 is, for example, a discrimination signal for discriminating a plurality of songs recorded on a magnetic tape, and includes an 8-bit synchronization signal (SYNC), a 1-bit presence or absence of song A, and an 8-bit BCD code. It is a serial digital signal of a total of 32 bits, consisting of a track number B, a 9-bit time code C, a 5-bit parity P, and a 1-bit termination D.

The data signal 16 is sequentially inserted into the control signal 10 sections _A3 to _A5 one bit at a time for each revolution of the rotary head of the helical scan type magnetic recording/reproducing apparatus.

Therefore, for example, if the head rotates 32 times per second, the data signal 16 can be inserted into the control signal 10 and recorded in one second, and then reproduced.

The number of bits of the data signal 16 is appropriately determined depending on the rotation speed of the rotary head.

(Effects of the Invention) The present invention is a control signal recording method that is compatible with conventional recorded magnetic tapes, and uses a control signal with a recording wavelength shorter than the recording wavelength of the conventionally used control signal. , it is possible to provide a control signal recording method that can extremely reduce interlayer transfer during magnetic transfer.

Further, the present invention is a control signal recording method that is compatible with conventional recorded magnetic tapes, has a recording wavelength shorter than the recording wavelength of conventionally used control signals, and has a control signal recording method that is compatible with conventional recorded magnetic tapes. The present invention further provides a signal recording method in which other information can be recorded using a control track by recording a signal different from a control signal on a portion of the magnetic tape, thereby improving the effectiveness of using a magnetic tape. This method has the effect of maintaining compatibility with known control signals in that a magnetic tape on which control signals are recorded can be reproduced by a conventional magnetic recording and reproducing device.

Furthermore, the present invention provides that even when a conventional magnetic recording/reproducing apparatus reproduces a magnetic tape on which a control signal and a signal different from the control signal are simultaneously recorded by the method of the present invention, this conventional apparatus can be used as a video track. Since only the magnetization reversals of the first and second magnetization sections used as position references are detected, compatibility with known control signals can be maintained.

It is something that can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the recording state of a conventional recorded magnetic tape used in a helical scan type magnetic recording and reproducing device, and FIG. 2 is a timing chart showing the waveforms of control signals used in the conventional and the present invention. Figure A shows the waveform of control signal 3, Figures B to I show the waveforms of control signals used in the present invention and signals for explaining the present invention, and Figure 3 is similar to Figure 2B. FIG. 4 is a diagram showing a recorded magnetic tape on which the control signal 5 shown in FIG. It is a diagram showing the contents. 1...Magnetic tape, 2...Video track,
3, 5, 7, 10...control signal, 4,
6, 8...Control track, 15...Data signal, A, _A1 to _A5 , B, B1, _{B2 ,} C, _C1 , _C2
...Interval, D, E...Discrimination level, T...Period.

Claims (1)

[Scope of Claims] 1. A control signal recording method for recording a control signal, which is a reference signal indicating the position of a video track on a magnetic tape, on a control track of a magnetic tape, which is used in a helical scan type magnetic recording and reproducing device, comprising: One cycle of the control signal includes a no-signal section having a no-signal level that is not magnetized, and first and second magnetized sections that are used as video track position references and are adjacent to the no-signal section and have signal levels of opposite polarity. A control signal recording method, characterized in that a recording wavelength recorded on the control track of the control signal is made shorter than a cycle of the control signal. 2. A control signal recording method for recording a control signal, which is a reference signal indicating the position of a video track on a magnetic tape, on a control track of a magnetic tape, used in a helical scan type magnetic recording/reproducing device, comprising: The period consists of a no-signal section having a no-signal level that is not magnetized, and a first signal section that is used as a position reference of the video track and has a signal level of opposite polarity adjacent to the no-signal section.
and a second magnetization section, in which the recording wavelength recorded on the control track of the control signal is shorter than the cycle of the control signal, further comprising the step of: A control signal recording method characterized in that a signal different from the control signal is interposed and recorded by providing a magnetization section in which magnetization reversal occurs in a direction opposite to the magnetization reversal in the first and second magnetization sections.