JPH0298808A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a new signal while accurately holding synchronism with a signal which is already recorded on a magnetic tape by setting the external diameter of a rotary body relatively to the distance between a magnetic head for reproduction and a magnetic head for recording. CONSTITUTION:The magnetic recording and reproducing device is equipped with the magnetic head 12 for reproduction and magnetic head 13 for recording which are arranged in the traveling direction of a magnetic tape 11 and a rotating body 21 provided having its outer peripheral surface in contact with the magnetic tape 11, and the external diameter of the rotating body 21 is set nearly <=1.2 time as large as the value obtained by dividing the distance between the magnetic head 12 for reproduction and magnetic head 13 for recording by the circle ratio. Therefore, the deviation between the position that the same position of the magnetic tape 11 passes after a specific delay time due to the error correction processing, etc., of, for example, data after passing the position of one magnetic head and the position of the other magnetic head is suppressed small. Consequently, a new signal can be recorded while the synchronism with the signal which is already recorded on the magnetic tape is maintained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to, for example, multi-channel recording, punch-in,
The present invention relates to a magnetic recording and reproducing apparatus used in cases such as punch-out and the like where it is necessary to record a new signal while maintaining synchronization with a signal already recorded on a magnetic tape.

[Conventional technology]

In recent years, for example, when recording the sounds emitted by a large number of musical instruments being played, instead of using multiple microphones to simultaneously record the sound, methods have been introduced in which each instrument is played separately and recorded overlappingly. The sound method is becoming popular.

When recording as described above is performed, for example, a multi-channel magnetic recording/reproducing device is used. In other words, each channel is assigned to each microphone or instrument, and while the sound of the previously recorded channel is played back, the sound of another instrument is sequentially recorded on another channel, and the sound collection is repeated multiple times. Multichannel synchronous recording is performed.

Also, even when recording simultaneously using multiple microphones,
Sound collection is not necessarily completed in one recording. For example, after recording by assigning channels to individual microphones or musical instruments, it is often necessary to re-record only a certain sound on a specific channel, so-called pan-nine or punch-out. For this reason, multichannel magnetic recording and reproducing devices are often used.

In such a multi-channel magnetic recording/reproducing device, it is essential to be able to maintain highly accurate synchronization between each channel on the magnetic tape. Therefore, in the case of an analog multi-channel magnetic recording and reproducing device, high synchronization accuracy can be maintained by using, for example, an inductive type magnetic head and using the same magnetic head for both the reproducing function and the recording function. It is now possible to

On the other hand, in recent years, digital multi-channel magnetic recording and reproducing devices, which have been widely used in place of analog magnetic recording and reproducing devices, perform interleaving, deinterleaving, error correction, etc. on the reproduced and recorded data. Because the processing is performed, data that is reproduced or recorded is delayed by the time required for these processing.

Therefore, in this type of magnetic recording/reproducing device, there is a lag between the time when the data recorded on the magnetic tape is reproduced by the reproducing magnetic head and the time when the reproduced data is output from the magnetic recording/reproducing device. occurs. Similarly, there is a lag between the time when data is manually input to the magnetic recording/reproducing device and the time when the input data is recorded on the magnetic tape by the recording magnetic head.

Therefore, even if the same magnetic hand is used for both the playback and recording functions as in the analog multi-channel magnetic recording and playback device, synchronized recording cannot be performed.

Therefore, in conventional magnetic recording and reproducing devices, two magnetic heads, a reproducing magnetic head and a recording magnetic head, are arranged side by side in the running direction of the magnetic tape at a predetermined interval.

In other words, by making the time difference that occurs when the same location on the magnetic tape passes through each magnetic head equal to the delay time that occurs due to processing such as error correction of the data, each time on the magnetic tape is It became possible to maintain synchronization accuracy between channels.

[Problem to be solved by the invention]

As mentioned above, in order to absorb the data delay time due to the time difference when the magnetic tape passes two magnetic heads, the distance traveled by the magnetic tape during this data delay time must be exactly the same as the two magnetic heads. It is necessary to control the running speed of the magnetic tape so that it is equal to the distance between the magnetic heads.

However, even when feedback control is performed, the running speed of a magnetic tape varies due to variations in the outer diameter and eccentricity of the capstan and pinch roller, as well as variations in the hardness of the pinch roller. Frequency component speed fluctuations tend to occur. Therefore, after the same point on the magnetic tape passes the position of one magnetic head, it reliably passes the position of the other magnetic head after a predetermined delay time caused, for example, by data error correction processing. Therefore, it is difficult to control the running speed of the magnetic tape.

Another possibility is to add a flywheel to the capstan to increase the moment of inertia and reduce speed fluctuations of the magnetic tape, but even this cannot significantly reduce speed fluctuations and would increase the size of the device. will be invited.

Therefore, with conventional magnetic recording and reproducing devices, it is difficult to record new signals while maintaining accurate synchronization with signals already recorded on the magnetic tape, such as between channels on the magnetic tape. It had the problem that.

[Means to solve the problem]

In order to solve the above problem, the magnetic recording and reproducing apparatus according to the invention of claim 1 includes a reproducing magnetic head and a recording magnetic head that are arranged in parallel in the running direction of the magnetic tape, and a magnetic recording head whose outer peripheral surface is magnetic. In a magnetic recording/reproducing apparatus including a rotating body provided in contact with the tape, the outer diameter of the rotating body is approximately 1. It is characterized by being set so that it is less than twice as large.

In order to solve the above-mentioned problem, the magnetic recording/reproducing device according to the invention of claim 2 has a reciprocating magnetic head and a recording magnetic head, which are arranged in parallel in the running direction of the magnetic tape, and an outer circumferential surface of the magnetic recording head. In a magnetic recording/reproducing device comprising a rotating body provided in contact with a magnetic tape, the outer diameter of the rotating body is approximately an integer of the distance between the magnetic reproduction head and the recording magnetic head divided by the circumference of pi. It is characterized by being set to be 1/1/2.

[For production]

According to the configuration of claim 1, the same location on the magnetic tape passes through the position of one magnetic head, which occurs due to variations in the outer diameter or eccentricity of a rotating body such as a capstan or a pinch roller. The deviation between the position of the other magnetic hand and the position of the other magnetic hand increases and decreases repeatedly as the outer diameter of the rotating body is set smaller. Nakara O
It converges to , and is kept small enough so that at least the synchronization with the signals already recorded on the magnetic tape is not impaired.

Therefore, new signals can be recorded while accurately maintaining the synchronization relationship with signals already recorded on the magnetic tape, such as between channels on the magnetic tape.

According to the structure of claim 2, the outer diameter of the rotating body such as the capstan or the pinch roller is theoretically optimized.
Regardless of variations in the outer diameter or eccentricity of the rotating body, the same point on the magnetic tape passes the position of one magnetic head and after a predetermined delay time caused by, for example, data error correction processing has elapsed. , the 641 tape can be run so as to reliably pass the position of the other magnetic head.

Therefore, like the magnetic recording and reproducing apparatus according to the invention of claim 1, new signals can be generated while accurately maintaining the synchronization relationship with the signals already recorded on the magnetic tape, such as between each channel on the magnetic tape. Signal recording can be performed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

As shown in FIG. 1, a magnetic recording and reproducing device (hereinafter referred to as MTR) that records and reproduces, for example, four-channel signals on a magnetic tape 11 includes a first magnetic head for reproduction 12, a recording magnetic head 12, A magnetic head 13 and a second reciprocating magnetic head 14 are arranged in sequence in the running direction of the magnetic tape 11 as indicated by arrow A. These magnetic heads 12
-14 are each fixed on a suspension device (not shown),
It is designed to come into sliding contact with the running magnetic tape 11.

The first rehousing magnetic head F12 and the second reproducing magnetic head 14 each receive an electric signal electromagnetically converted from a magnetic signal recorded on the magnetic tape 11 by these reproducing magnetic heads 12 and 14. Amplification circuit 15 that amplifies
・Connected to 17. On the other hand, the recording magnetic head 13
is connected to a recording signal amplification circuit 816 for driving this recording magnetic head 13.

The amplification circuits 15 and 17 and the recording signal amplification circuit 16 are
It is composed of a PLL circuit, a waveform equivalent circuit, a modulation/demodulation circuit, an interleaving circuit, a decreep circuit, an error correction circuit, an error correction code addition circuit, etc., and is connected to a signal processing circuit 18 that processes reproduction signals and recording signals. There is. The processing performed by this signal processing circuit 18 includes, for example, so-called interleaving, in which the data to be recorded is scattered on the magnetic tape 11 when recording digital signals, and data recorded in increments. , so-called dinterleaving, which rearranges the data in memory during playback, is now performed.

The MTR is also provided with a cab stan 21, which is a rotating body whose outer peripheral surface is in contact with the magnetic tape 11, a pinch roller 22, and a guide roller 23. The capstan 21 is driven by a drive means (not shown) to rotate, pinches the magnetic tape 11 between a rotatably provided pinch roller 22, and runs the magnetic tape 11. On the other hand, the guide roller 23 is rotatably provided to guide the magnetic tape 11.

The rotational speed of the capstan 21 is controlled so that the running speed of the magnetic tape 11 is maintained at a constant speed when recording new data, but it is controlled so that the running speed of the magnetic tape 11 is maintained at a constant speed when recording new data, and when reproducing recorded data or re-recording. is feedback-controlled so that the speed does not cause an excess or deficiency in the amount of data temporarily stored in the memory for deinterleaving performed on the reproduced signal. That is, magnetic tape 1
Even if the linear recording density of the magnetic signal recorded in 1 is uneven or dense due to fluctuations in the rotational speed of the capstan 21 during recording, recording will not be possible for a memory whose size is determined by circuit scale constraints, etc. The capstan 2
1 rotation speed is controlled.

By using the above-mentioned MTR, four track patterns 31 to 34 corresponding to four channels are formed on the magnetic tape 11, for example, as shown in FIG. A magnetic signal is recorded. Here, the arrangement of the track patterns 31 to 34 formed on the magnetic tape 11 is not limited to the arrangement in which the l channel is the first track, but the arrangement in which the l channel is made up of a plurality of tracks is also possible. good.

For example, on the magnetic tape 11 on which signals of four channels are recorded, a re-recording start point P (hereinafter, punch-in point
(hereinafter referred to as punch-in), starts recording a new signal while maintaining synchronization with the already recorded signal (hereinafter referred to as punch-in), and re-recording end point Q (hereinafter referred to as punch-out point Q). to finish recording the new signal (
(hereinafter referred to as punch-out), the following operations are performed in the MTR.

First, the magnetic signal recorded at the punch-in point P is electromagnetized by the first magnetic head for reproduction 12 when the punch-in point P passes through the magnetic gap 1.2a of the first magnetic head for reproduction 12. converted. The electromagnetically converted electrical signal is amplified by the amplifier circuit 15, and subjected to processing such as deinterleaving in the signal processing circuit 18, resulting in a time difference of ΔL1.
, and is output from the signal processing circuit 18 to an output device (not shown).

On the other hand, a signal newly recorded by punch-in is inputted to the signal processing circuit 1 from an input device (not shown), processed by the signal processing circuit 18 such as increment, delayed by a time ΔL2, and then sent to the recording signal amplification circuit 18. 16, the signal is electromagnetically converted by the recording magnetic head 13, and recorded as a magnetic signal on the magnetic tape 1.

Here, the pan-nine point P is the first reproducing magnetic head 1
The time Δ after passing through the magnetic gap 12a of 2 is 1 ΔL.
, +Δt2, it is necessary to accurately pass through the magnetic gap 1.3a of the recording magnetic head 13.

To do this, set the reference running speed of the magnetic tape 11 to ■. Then, the distance between the magnetic gap 12a in the first magnetic heald 12 for reproduction and the magnetic gap 13a in the magnetic heald 13 for recording! .

may be set as shown in equation (1) in Table 1.

However, the actual running speed of the magnetic tape 11 depends on the capstan 21, pinch roller 22, and guide roller 2.
Variations in the outer diameter and eccentricity of the pinch roller 22, variations in the hardness of the pinch roller 22, etc. cause speed fluctuations in various frequency components, and the recording density of magnetic signals on the magnetic tape 11 tends to be uneven. Become.

For example, the actual running speed Vr at the time of day is expressed as kv, the rate of variation in the running speed of the magnetic tape 11, and f, the variation frequency.
Let the initial phase be ν. Then, the formula (2% formula%) Also, the recording linear density B of the magnetic signal on the magnetic tape 11 is
When the standard recording linear density is 80, the formula (3% formula %) By the way, when the signal recorded on the magnetic tape 11 is reproduced or re-recorded, as mentioned above, the running speed of the magnetic tape II depends on the reproduction signal Cab Stuff 2
10 The rotational speed is controlled by the feed bank, but when such a feedback servo is activated, the actual running speed Vp of the magnetic tape 11 is expressed by the formula (
4) It will look like this. Here, νS is the initial phase and 1.
Furthermore, the servo speed Vs is defined as the ideal amount of data in the memory is Mo (=8.12°), the amount of data in the memory at the time is M (L=O and M=M0), and the servo gain is k. Then, it is expressed as 2 (5).

Furthermore, the amount of data M in the memory at time t is expressed by the formula (6
), so if M and −M are represented by m, m is expressed as the formula (
3), (4), (5), and (6), formula (7) is obtained.

When this (7) is solved for m under the conditions of 1=0 and m=o, equation (8) is obtained.

On the other hand, after the data read from the playback head at a certain time t=T is subjected to signal processing, the difference Δρ between the distance the tape travels until it is recorded from the recording head to the tape and the distance it should travel is , Equation (9% Equation %) Then, from Equations (4), (5), and (9), this Δf is
Since m (12
)become that way.

In equation (2), the exponential term indicates a transient phenomenon, so if we focus only on the steady term, we get equation (13).

Then, to summarize the sine term in (13), the delay time of the signal reproduced by the first reproducing magnetic head 12, that is, the pan-nine point P is the first reproducing magnetic head 12. Since the time ΔL required to travel from the magnetic gear knob 12a of the magnetic gear knob 12a to the magnetic gap 13a of the recording magnetic head 13 is expressed as 2 (15) as shown in Table 3, the above equation (14) is It is expressed as (16).

From this equation (16), it can be seen that if f×ΔL satisfies the relationship shown by equation (17), the error Δρ will theoretically become O.

Incidentally, periodic deviations in the running speed Vp of the magnetic tape 11, that is, wow and flutter, occur mainly due to variations in outer diameters and eccentricity of rotating bodies such as the capstan 21, the pinch roller 22, and the guide roller 23. .

Therefore, the frequency of the wow flank is expressed by equation (18), where D is the outer diameter of the rotating body. Here, i is a positive integer, f when i=1 is the fundamental frequency, and i
When ≧2, f becomes the i-th frequency.

On the other hand, in the above equation (16), the error ΔL involved is
Since the main amplitude component ξ of the variation in l is expressed by equation (19), substituting the above equation (18) into equation (19) yields equation (20).

That is, for example, when the distance 2° between the magnetic gap 12a and the magnetic gap 13a is 25+II[l,
As shown in FIG. 3, the main amplitude component ξ of the fluctuation of the error Δ° C. is, as shown in FIG. 3, when the outer diameter of the rotating body is D=1. When /π = 7.96 mm, it theoretically becomes 0 for a positive integer i, but if the outer radius of the rotating body is larger than 7.96 mm, the main amplitude component of the fluctuation ξ is never O, and there is a monotonically increasing relationship between the outer diameter and the main amplitude component ξ of the fluctuation.

Conversely, when the outer diameter of the rotating body is smaller than 7.96 mm, the main amplitude component ξ of the fluctuation does not increase or decrease repeatedly and converges to 0 as the outer diameter is set smaller. In particular, when the outer diameter of the rotating body is an integer fraction of 7.96 nm,
The main amplitude component ξ of the fluctuation is also theoretically O.

Further, similarly to the case where the interval 10 between the magnetic gap 12a and the magnetic gap 13a is 25 degrees, the interval P0 is 1
0 and 15IlIl11, the outer diameter of the rotating body and the error Δ! The relationship between the fluctuation of ξ and the main amplitude component ξ is shown in FIG. Therefore, in each case, the magnitude of wow and flutter was measured when the magnetic tape 11 was run with the outer diameter of the capstan 21 set to 5 mm.

Here, the measurement of wow and flutter was performed as follows. First, a signal of a single frequency is recorded on the magnetic tape 11 while the magnetic tape 11 is running. Next, a reproducing magnetic head was attached in place of the recording magnetic head 13 so that the magnetic gap was at the same position, and the signal of the single frequency was recorded.E1! The air tape 11 is run. At this time, while reading the frequency of the signal reproduced by the first reproducing magnetic head 12, a feedback servo is operated based on this to control the running speed of the magnetic tape 11.

At this time, the magnitude of the frequency fluctuation of the signal reproduced by the reproducing magnetic head attached in place of the recording magnetic head 13 is measured using a wow and flutter meter. As a result, the results shown in Table 4 were obtained.

That is, the outer diameter of the capstan 21 is 5 nun,
The distance p0 between the magnetic gap 1.2a and the magnetic gap 13a is 1011II! When 1, L/π'i3.2
and is not equal to D. In this case, wow and flutter was 0.3%. On the other hand, capstan 21
When the outer diameter of is 51Tl111 and the distance 1° between the magnetic gap 12a and the magnetic gap 13a is 1.5m111, the outer diameter and the distance 2° are ρ. /π-4,8'=i
In this case, it was confirmed that the wow and flutter was 0.1%, which was lower than when the interval E0 was 10 degrees.

In this way, the outer diameter of the rotating body is approximately 1.5 times the distance L/π between the magnetic gap 12a and the magnetic gap 1.3a. 2
If it is less than double, the difference between the position of the same point on the magnetic tape 11 passing through the magnetic gap 12a after time Δt and the position of the magnetic gap 13a has already been recorded on the magnetic tape 11. This can be kept sufficiently small so as not to impair the synchronization relationship with the current signal. In particular, if the outer diameter of the rotating body is the magnetic gap 1
If the distance between 2a and the magnetic gap 13a is set to an integer fraction of 10/π, the magnetic gap 13a can be reliably closed after a time ΔL has elapsed since the same location on the magnetic tape 11 passes through the magnetic gap 12a. can be made to pass through.

Therefore, for example multi-channel recording or bunch-in,
New signals can be recorded while reliably maintaining synchronization with signals already recorded on the magnetic tape 11, such as punch-out and punch-out.

In this embodiment, the first reproducing magnetic head 12 and the recording magnetic head 1 are arranged in order in the running direction of the magnetic tape 110.
Although an example of a digital MTR in which feedback servo control is performed based on data reproduced by the first reproduction magnetic head 12 has been described, the present invention is not limited to this. For example, analog M
The present invention may be applied to the TR, and the same effect can be obtained even when the first reproducing magnetic head 12 and the recording magnetic head I3 are arranged in reverse.

Furthermore, even when feedback servo control is not performed, if the servo gain k is O, then a=O in equations (14) and (16), so the same effect can still be obtained.

[Margin below]

[Effects of the Invention] As described above, the magnetic recording and reproducing device according to the invention of claim 1 has a reproducing magnetic head and a recording magnetic head that are arranged in parallel in the running direction of the magnetic tape, and whose outer peripheral surface is In a magnetic recording and reproducing apparatus including a rotating body provided in contact with a magnetic tape, the outer diameter of the rotating body is approximately 12 times the distance between the magnetic head for reproduction and the magnetic head for recording divided by the circumference of the magnetic tape. The configuration is set to be less than twice that.

As a result, the position where the same point on the magnetic tape passes after passing the position of one magnetic head and the position where it passes after a predetermined delay time caused by, for example, data error correction processing, etc., can be changed from the position of the other magnetic head. The deviation can be kept sufficiently small.

Therefore, it is possible to record new signals while accurately maintaining the synchronization relationship with signals already recorded on the magnetic tape, such as between channels on the magnetic tape.

As described above, the magnetic recording and reproducing apparatus according to the invention of claim 2 includes a reproducing magnetic head and a recording magnetic head that are arranged in parallel in the running direction of the magnetic tape, and the magnetic recording head and the recording magnetic head that are arranged so that the outer peripheral surface is in contact with the magnetic tape. In a magnetic recording and reproducing apparatus, the outer diameter of the rotating body is approximately an integer fraction of the distance between the reproducing magnetic head and the recording magnetic head divided by the circumference of the pi. This is the configuration set as follows.

As a result, after the same point on the magnetic tape passes the position of one of the magnetic heads, a predetermined delay time caused by, for example, data error correction processing has elapsed.
The magnetic tape can be run so as to reliably pass the position of the other magnetic hend.

Therefore, like the magnetic recording and reproducing apparatus according to the invention of claim 1, new signals can be generated while accurately maintaining the synchronization relationship with the signals already recorded on the magnetic tape, such as between each channel on the magnetic tape. This has the effect that signals can be recorded.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is an explanatory diagram showing the configuration of an MTR, and Figure 2 is an explanatory diagram showing the configuration of a track pattern formed on a magnetic tape. , FIG. 3 shows that the distance 10 between the magnetic gap of the first reproducing magnetic head and the magnetic gap of the recording magnetic head is 25 m.
Figure 4 is a graph showing the relationship between the outer diameter of the rotating body and the main amplitude component ξ of the fluctuation of error Δl when m is 10 mm.
, and the outer diameter of the rotating body and the error Δ! when it is 15 mm. 2 is a graph showing the relationship between the fluctuation of ξ and the main amplitude component ξ. 11 is a magnetic tape, 12 is a first reproducing magnetic head, 1
3 is a recording magnetic head, 21 is a capstan (rotating body)
, 22 is a pinch roller (rotating body) 23 is a guide roller (
(rotating body).

Claims (1)

[Claims] 1. Magnetic recording comprising a reproducing magnetic head and a recording magnetic head arranged in parallel in the running direction of a magnetic tape, and a rotating body provided so that its outer peripheral surface is in contact with the magnetic tape. The reproducing device is characterized in that the outer diameter of the rotating body is set to be approximately 1.2 times or less the distance between the reproducing magnetic head and the recording magnetic head/the circumference ratio. Magnetic recording and reproducing device. 2. In a magnetic recording and reproducing apparatus comprising a reproducing magnetic head and a recording magnetic head arranged in parallel in the running direction of the magnetic tape, and a rotating body disposed so that its outer peripheral surface is in contact with the magnetic tape, the rotation 1. A magnetic recording and reproducing device, characterized in that the outer diameter of the body is set to be approximately one integer fraction of the distance between a reproducing magnetic head and a recording magnetic head divided by the circumference of pi.