JPH10162303A - Magnetic recording device and magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable recording and reproducing under a long time mode by using alternately two rotary heads having different azimuths only and forming their tracks in turn on a magnetic tape. SOLUTION: The 1st azimuth rotary head Ha and the 2nd azimuth rotary head Hb are fixedly fitted to the bottom surface of a cylindrical rotary drum opposite to each other at the same height with their gap surfaces slightly protruded from the outer circumferential side surface of the rotary drum. The magnetic tape 10 is slantwise wound around the outer circumferential side surface of this rotary drum over an angular range of 180 degrees, and is held between a capstan and a roller to be traveled in a fixed direction. Then, the rotary drum fixed with the rotary heads Ha and Hb is controlled to be rotated 1.5 times as fast as at the time of an ordinary mode, while the traveling speed of the magnetic tape 10 is controlled to be 1/2-fold as fast as the ordinary mode, thus performing the recording and reproducing under the long time mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus and a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording apparatus and a magnetic recording / reproducing apparatus which record digital information on a magnetic tape for a long time by a rotary head and reproduce the digital information.

[0002]

2. Description of the Related Art Conventionally, two rotating heads provided at 180 degrees opposite to a cylindrical rotating body (hereinafter referred to as a rotating drum) obliquely cover the outer peripheral side surface of the rotating drum over an angle range of about 180 degrees. 2. Description of the Related Art A helical scan type magnetic recording / reproducing apparatus configured to record and reproduce an information signal on a magnetic tape wound and running at a constant speed is widely known. In such a magnetic recording / reproducing apparatus, usually, the two rotating heads are different in azimuth angle from each other in order to improve the recording density, and the information signal recording track is provided with a guard band without or with a very narrow guard band. The recording is formed closely on top.

In such a helical scan type magnetic recording / reproducing apparatus, as a recording / reproducing apparatus for recording digital information on a magnetic tape for a long time and reproducing the same, for example, the tape traveling speed is set to one of the standard traveling speed of the normal mode.
There has been known a magnetic recording / reproducing apparatus capable of recording digital information on a magnetic tape for three times as long as the normal mode, with the rotation speed of the rotary drum being the same as the normal mode (Japanese Patent Publication No. 6-18047).

In this magnetic recording / reproducing apparatus, the number of rotations of a rotary drum in which two rotary heads having different azimuth angles are attached to face each other is the same as that in the normal mode. An information signal is recorded and reproduced by forming inclined tracks alternately on the magnetic tape by two rotating heads at a rate of degree. According to this magnetic recording / reproducing apparatus, azimuth recording can be performed in the long-time mode, which is an odd multiple of the recording time in the normal mode.

On the other hand, in order to perform recording in the long mode in which the recording time is an even multiple of the recording time in the normal mode, if only the tape running speed is set to, for example, 倍 of the normal mode, one rotation of the rotating drum is required. The information signal is recorded on the magnetic tape at a rate of degree, and since the information signal is recorded by only one of the two rotary heads, all the recording tracks have the same azimuth angle,
Regeneration using the azimuth loss effect becomes impossible. Therefore, in order to perform even-number-time recording even in the long-time mode, another rotating head is added, and intermittent recording is performed by a method of two-channel recording or one of the standard heads and an additional head having an azimuth angle different from that of the standard head. Method (JP-A-6-3)
No. 25305) is conventionally known.

Digital information is recorded on a magnetic tape by setting the rotation speed of the rotary drum and the tape running speed to 倍 times that of the normal mode. By setting only the value to 倍 of the normal mode, data having a recording data rate of 倍 that of the normal mode can be recorded.

[0007]

However, in order to perform two-channel recording, a recording system (modulation circuit, recording amplifier, etc.) and a reproduction system (reproduction amplifier, equalizing circuit, phase locked loop for data clock reproduction, etc.) are required. Two systems are required, and the cost of the magnetic recording / reproducing apparatus increases.

In the case of odd-number-times recording, the rotating heads need only be two opposing rotating heads having the same mounting height. However, in the case of even-number-times recording, at least the one rotating head is replaced with the mounting height and azimuth. Two rotating heads (double azimuth heads) having different angles are required, which makes the height adjustment cumbersome and increases the cost of the head.

Further, in a digital data recorder, data of about 14 Mbps can be recorded for 5 hours as standard. However, even if the data is 7 Mbps, conventionally, dummy data is added and the data rate is converted to about 14 Mbps and recorded. Therefore, the recording time is the same 5 hours, and the recording time cannot be lengthened. On the other hand, digital information is recorded on a magnetic tape with the rotation speed of the rotating drum and the tape running speed each being half the normal mode, and during playback, the drum rotation speed is the same as in the normal mode, and only the tape running speed is normally set. According to the conventional apparatus in which the mode is 倍 times, the recording time of data having a recording data rate of 7 Mbps can be reduced to about 10 hours. However, according to this conventional apparatus, there is a problem that an error rate of reproduced data is deteriorated because a scanning track of the rotary head during reproduction is different from a recording track.

[0010] The present invention has been made in view of the above points,
It is an object of the present invention to provide a magnetic recording device and a magnetic recording / reproducing device capable of recording and reproducing digital information for a long time with an inexpensive configuration.

It is another object of the present invention to provide a magnetic recording apparatus and a magnetic recording / reproducing apparatus capable of recording and reproducing digital information for a long time with a good error rate without increasing the cost.

[0012]

In order to achieve the above object, a magnetic recording apparatus according to the present invention employs two rotating heads provided 180 degrees opposite to each other on a rotating drum to provide a rotating drum with an outer peripheral surface of about 180 degrees. In a normal mode, two rotating heads are used alternately to form a sequential track to record a digital information signal on a magnetic tape wound obliquely over an angle range of degrees. In a helical scan type magnetic recording device, the running speed of a magnetic tape is increased by 1 / (2n) times that in a normal mode (however,
n is an arbitrary natural number), a rotating drum rotation controlling means for increasing the rotating speed of the rotating drum by (2n + 1) / (2n) times in the normal mode, and (2n) of the rotating drum.
+1) Recording means for forming a sequential track on a magnetic tape by alternately using two rotary heads at a rate of once per 回 転 rotation and recording digital information signals in a long-time mode. It is.

According to the present invention, the running speed of the magnetic tape is set to 1 / (2n) times that of the normal mode, and
Since the digital information signal is recorded by alternately using two rotary heads at a rate of +1) / 2 rotations, a long recording time of 2n times as long as in the normal mode in a pattern in which the azimuth angles of adjacent recording tracks are different. Can be.

Further, the magnetic recording / reproducing apparatus of the present invention increases the running speed of the magnetic tape to 1 / (2n) times (where n is an arbitrary natural number) of the normal mode for both recording and reproduction in the long time mode. Tape running means for rotating the rotating drum, rotating drum rotating control means for setting the number of rotations of the rotating drum to (2n + 1) / (2n) times the normal mode for both recording and reproduction in the long-time mode, and changing the frequency of the digital information signal to ( 2n + 1) /
(2n) times recording signal signal processing means and two rotating heads are used alternately at a rate of once per (2n + 1) / 2 rotations of the rotating drum to form sequential tracks on a magnetic tape for recording. Two rotating heads are used from recording means for recording the digital information signal from the signal processing means in the long-time mode and magnetic tape on which the digital information signal is recorded in the long-time mode. And a reproduction circuit for decoding the digital information signal reproduced by the reproduction.

According to the present invention, recording and reproduction can be performed in the normal mode and the long-time mode of 2n times using two rotating heads.

Further, in order to achieve the above object, the magnetic recording / reproducing apparatus of the present invention sets the traveling speed of the magnetic tape to 1 / (2
n) times (where n is an arbitrary natural number), and the number of rotations of the rotating drum is (2n + 1) / (2n) times that of the normal mode during long-time mode recording, and the long-time mode playback Is a rotating drum rotation control means for controlling the number of rotations to the same as in the normal mode, and (2n + 1) / 2 of the rotating drum.
A recording means for recording a digital information signal in a long-time mode by forming sequential tracks on a magnetic tape by alternately using two rotating heads at a rate of one rotation, and a digital information signal in a long-time mode And a reproducing circuit for decoding a digital information signal reproduced from the magnetic tape using two rotating heads.

According to the present invention, recording and reproduction can be performed in the normal mode and the long-time mode of 2n times using two rotary heads, and since the characteristics of the reproduction circuit need not be switched, the same reproduction circuit as in the normal mode is used. Thus, a reproduction signal in a long time mode can be obtained.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention. In the figure, a rotating head H of a first azimuth angle is opposed to the bottom surface of a cylindrical rotating drum (not shown) at the same height position.
a and a rotary head Hb having a second azimuth angle are attached and fixed such that their gap surfaces slightly protrude from the outer peripheral side surface of the rotary drum. A magnetic tape 10 is wound obliquely and over an angle range of about 180 degrees around the outer peripheral side surface of the rotating drum, so that the magnetic tape 10 is sandwiched by capstans and rollers (not shown) and travels in a certain direction. Has been.

Here, in the first embodiment of the present invention,
The rotating drum to which the rotating heads Ha and Hb are fixed is controlled to rotate at 1.5 times the speed in the normal mode, and the tape traveling speed of the magnetic tape 10 is １ ／ of that in the normal mode.
It is assumed that recording and reproduction in the long-time mode are performed in a state where the control is performed twice.

Here, the outline of the rotation control of the rotary drum will be described. For example, 1/60 in the normal mode.
Assuming that the rotating heads Ha and Hb alternately record and reproduce one inclined track every second, the rotating speed of the rotating drum is controlled at 45 rps in the long time mode because the rotating speed of the rotating drum is 30 rps. . Therefore, a known means based on a speed detection signal from a frequency generator (FG) proportional to the rotation speed of the drum motor so that the rotation speed of the drum motor for rotating the rotary drum is 45 rps in the long time mode. In addition to controlling the speed, a repetition frequency of 4 obtained by detecting the rotation of the rotating drum for each rotation by a known pickup head.
The 5 Hz rotation detection pulse is divided by 1/3 to 15 Hz. At the time of recording, the 15 Hz signal obtained by dividing the 60 Hz vertical synchronizing signal by 1/4 at the time of recording and the 15 Hz signal from the oscillator at the time of reproduction are used. The phase is compared with a reference signal, and the rotational phase of the drum motor is controlled by the obtained phase error signal.

The tape running speed of the magnetic tape 10 is controlled, for example, by a speed control based on a speed detection signal having a frequency proportional to the rotation speed of the capstan motor, and an output of an oscillator when the capstan rotation detection signal is recorded. The signal and the phase control based on the phase error signal obtained by comparing the phase with the reproduction control signal from the magnetic tape 10 at the time of reproduction are controlled by a known capstan motor speed and phase control method. Although not shown in FIG. 1, a control pulse having a constant period is recorded on the magnetic tape 10 by a fixed control head and reproduced.

Next, the operation at the time of recording of the embodiment shown in FIG. 1 will be described. The digital information signal to be recorded, input via the terminal 11, is stored in the memory 13 via the encoder / decoder circuit 12, and is stored in the encoder / decoder circuit.
After interleaving, error correction code addition, and the like are performed by an encoder in the encoder / decoder circuit 12 by transmitting and receiving signals between the decoder circuit 12 and the memory 13, the data is again stored in the memory 13 as encoded data.

Here, the digital information signal includes, for example, main data as main information and auxiliary data called a pack (data). Here, the pack includes a cassette ID, a time code, a recording date and time, source information (for example, a channel and a program index number when a digital broadcast signal is recorded), text data (for example, a title for each program, an outline, and the like), and the like. This is fixed-length data containing auxiliary information and its identification information.

The encoded data stored in the memory 13 is read out by the clock of the modulation / demodulation circuit 14, input to the modulation circuit in the modulation / demodulation circuit 14, and modulated. Here, the modulation circuit in the modulation / demodulation circuit 14 is configured, for example, as shown in the block diagram of FIG. In the figure, a formatter 22 converts additional information such as a synchronization signal into encoded data by a signal input from an encoder in an encoder / decoder circuit 12 via a terminal 21 and encoded data read from the memory 13. To a predetermined signal format.

On the other hand, the oscillator 23 oscillates and outputs a clock pulse having a frequency 6f which is six times the clock signal frequency f in the normal mode. The frequency is divided by 3 and １ ／ and input to the terminals 26 a and 26 b of the switch 26. Switch 26
Is based on the mode identification signal input via the terminal 15 also shown in FIG. 1, based on the terminal 26a when the mode identification signal indicates the normal mode, and on the terminal 26b when the mode identification signal indicates the long-time mode. Are respectively controlled by switching.

The frequency-divided pulse having the repetition frequency 2f or 3f selected by the switch 26 is supplied to a 1/2 frequency divider 27.
, Divided by 分, and input to the formatter 22 and the digital modulator 28 as clock pulses having a repetition frequency f or 1.5f, respectively. That is, the formatter 22 and the digital modulator 28 include:
A clock pulse having a repetition frequency f in the normal mode, and a repetition frequency 1.5f in the long mode.
Is input from the 1/2 frequency divider 27.

The digital modulator 28 is a formatter 22
The output digital information signal is modulated at a data rate in accordance with the input clock pulse and output. Therefore, in the long time mode, the digital modulator 28
Outputs a modulated digital information signal having a data rate 1.5 times that in the normal mode.

Returning to FIG. 1, the modulated digital information signal output from the modulation circuit in the modulation / demodulation circuit 14 is supplied to the switch circuit 16 where it is input from the terminal 17 where the rotary drum The recording / reproducing amplifier 18 and the recording / reproducing amplifier 18 connected to the rotating head that scans the magnetic tape 10 at every predetermined rotation of the rotating drum based on a head switching pulse generated by a known method in synchronization with the rotating phase of 19 are supplied to the rotary heads Ha and Hb alternately and supplied to the magnetic tape 10.
The inclined tracks are sequentially formed and recorded. Each inclined track stores a fixed amount of data area called a sync block corresponding to a data block, by rotating heads Ha, Hb.
Are arranged in accordance with the scanning of.

In the long-time mode, the rotation of the rotary drum is controlled to 1.5 times that in the normal mode, and the magnetic tape 10 is controlled to run at a speed half the running speed in the normal mode. The switching circuit 16 is controlled so that the digital information signal is alternately input to the rotary heads Ha and Hb at a rate of once every 1.5 rotations of the rotary drum and at intervals of 0.5 rotation. . This allows
The rotating heads Ha and Hb alternately scan the magnetic tape 10 every 0.5 rotation of the rotating drum. When, for example, recording is first performed by the rotating head Ha, the following rotating head H
No signal recording is performed during one rotation period in which b and Ha scan the magnetic tape 10 sequentially. After 1.5 rotations, the rotary head Hb moves to the next inclined track during 0.5 rotation period in which the magnetic tape 10 scans the magnetic tape 10. Is performed, and thereafter, in the same manner as described above, the rotating heads Ha and Hb are rotated once every 1.5 rotations.
Thus, recording of digital information signals is performed by alternately forming inclined tracks.

Therefore, in the long-time mode, track patterns recorded at the same track pitch as in the normal mode and adjacent tracks are respectively formed by the rotary heads Ha and Hb having different azimuth angles. In addition, in the long-time mode, the magnetic tape 10 is controlled to have a traveling speed that is 1/2 times the traveling speed in the normal mode. Therefore, it is necessary to add a double azimuth head or a rotary head for 2-channel recording. 10 hours on a magnetic tape that can record about 14 Mbps data for 5 hours in the normal mode by recording twice as long as in the normal mode with only the two rotary heads Ha and Hb. Can be recorded.

Next, the operation at the time of reproduction will be described. At the time of reproduction as well as at the time of recording, the rotation of the rotating drum is controlled to 1.5 times that of the normal mode in the long time mode, and the magnetic tape 10 is set to a traveling speed of 1/2 times the traveling speed in the normal mode. Is controlled. Therefore, even in the long time mode, the rotary heads Ha and Hb scan on the same scanning locus as the trace of the recorded inclined track of the recorded magnetic tape 10 to alternately reproduce the digital information signal, and the reproduced digital information signal is illustrated. The signal is supplied to the corresponding reproducing amplifiers in the recording / reproducing amplifiers 18 and 19 through a rotary transformer not to be amplified, and then supplied to the switch circuit 16.

The switch circuit 16 receives a head switching pulse input via a terminal 17 at every predetermined rotation of the rotary drum, that is, the rotary head on the side of the rotary heads Ha and Hb which scans the magnetic tape 10. The switching control is performed so as to select the reproduced digital information signal, and the signal is output to the demodulation circuit in the modulation / demodulation circuit 14. The demodulation circuit in the modulation / demodulation circuit 14 is configured, for example, as shown in the block diagram of FIG.

In FIG. 3, a reproduced digital information signal input through a terminal 31 is converted into a variable equalizer 32.
And given a predetermined equalizer characteristic. Here, since the data rates are different between the long time mode and the normal mode, the variable equalizer 32 and a phase locked loop (PLL) 34 described later are based on the mode identification signal input via the terminal 15. To switch the characteristics.

Here, the variable equalizer 32 has recently been
A configuration using an electronic filter that determines a frequency characteristic by controlling a voltage is generally used. For example, the configuration illustrated in FIG. 4 is used. The variable equalizer 32 includes an electronic filter 321 and a delay and adder 322 for performing (1 + D) partial response processing. The electronic filter 32 is controlled by a mode identification signal input through a terminal 15.
Reference numeral 1 denotes a configuration in which the frequency characteristic is variably controlled, and the delay / adder 322 has a configuration in which the delay amount D is variably controlled using a voltage-controlled variable delay line. As a result, the frequency characteristic of the variable equalizer 32 is, as shown in FIG. 5, the reproduction data rate in the long-time mode is 1.5 times that in the normal mode. Is changed to the frequency characteristic indicated by.

The reproduced digital information signal output from the variable equalizer 32 shown in FIG. 3 is supplied to a detector 33 and converted into digital data, and then input to a PLL 34 and a deformatter 35, respectively. The PLL 34 has a configuration in which the oscillation center frequency of the internal voltage controlled oscillator is switched according to the mode identification signal input via the terminal 15. The PLL 34 extracts the clock signal component of the input digital data and inputs the clock signal component to the deformatter 35. I do. The deformatter 35 synchronizes data based on the clock signal component input from the PLL 34, returns the digital information to the original digital information, and stores the digital information in the memory 13 of FIG.

Returning to FIG. 1, the memory 13
The data stored in the encoder / decoder circuit 12
, Where the data is subjected to error correction and deinterleaving, decoded into original digital data, and then output to the output terminal 20. At the time of long-time mode reproduction, each inclined track on the magnetic tape 10 is scanned twice by the rotary head having the same azimuth angle as the track, so that reproduced digital data from the same track is obtained twice. , Whichever has a higher error rate of the reproduced signal can be selected.

In the above-described embodiment, the long-time mode is described as performing twice the long-time recording / reproduction. However, the present invention is not limited to this, and it is essentially 2n (where n is an arbitrary number). When performing recording and reproduction for a long time (natural number) times, the tape traveling speed is set to 1 / (2
n) times, and the number of rotations of the rotating drum is (2n + 1) / (2n) times that of the normal mode, and the two rotating heads are alternated at a rate of once every (2n + 1) / 2 rotations of the rotating drum. Recording and playback may be used.

Next, a second embodiment of the present invention will be described. In this embodiment, at the time of recording, the number of rotations of the rotary drum is set to 1.5 times that in the normal mode, the tape running speed is set to 1/2 times that in the normal mode, and once every 1.5 rotations of the rotary drum. The first point is that recording is performed with a rotating head at a
However, unlike the first embodiment, the number of rotations of the rotary drum is the same as that of the normal mode at the time of reproduction, and the tape traveling speed is 倍 times that of the normal mode. Is what you do.

The head scanning angle (still angle) with respect to the longitudinal direction of the tape when scanning the magnetic tape with the rotary heads Ha and Hb while the running of the magnetic tape is stopped is _denoted by a ₀ in FIG. The scanning vector of the rotating head in the normal mode is denoted by d in the same figure, and the tape running vector in the normal mode is denoted by t in the same figure. The track angle at that time is a ₁ .

As a conventional method for performing twice the long-time recording / reproduction described above, there is known a method in which the number of rotations of the rotating drum and the traveling speed of the magnetic tape during recording are respectively halved in the normal mode. However, the scanning vector of the rotary head in the still mode is indicated by (1/2) d in FIG. 7, and the running vector in the tape running of 1/2 times that in the normal mode is indicated by (1) in FIG.
/ 2) Assumed by t, the scanning vector of the rotary head when the rotational speed of the rotary drum and the traveling speed of the magnetic tape are each set to 1/2 of that in the normal mode is indicated by 42 in FIG. same track angle a ₁ between the normal mode is obtained when.

The rotation speed of the rotary drum is set to be the same as that in the normal mode, and the running speed of the magnetic tape is reduced to 1 / the speed in the normal mode.
Scan vector of the rotary head when the doubled is shown at 43 in FIG. 8, the track angle is a _2. FIG.
Where d is the scanning vector of the rotating head during still, (1 /
2) t indicates a running vector at the time of tape running 1/2 times that in the normal mode.

In the above-described conventional method of performing twice the long-time recording / reproduction, at the time of recording, the rotation speed of the rotary drum and the traveling speed of the magnetic tape are respectively set to 1/2 of those in the normal mode.
During playback, the rotation speed of the rotating drum is the same as in normal mode,
Since the running speed of the magnetic tape is set to 1/2 of that in the normal mode, the scanning locus of the rotating head during reproduction does not coincide with the recording track trace because the relative speed between the head and the tape during reproduction is different from that during recording. , deviation corresponding to the difference between the track angle a ₂ during reproduction shown in track angle a ₁ and 8 at the time of recording shown in FIG. 7 occurs.

The closer the track angle at the time of reproduction is to the track angle a ₁ at the time of recording, the better the error rate of the reproduced signal. In general, the lower the tape running speed, the smaller the track angle, and the smaller the drum rotation speed, the smaller the track angle.

In the present embodiment, the number of revolutions of the rotating drum is the same as in the conventional mode during reproduction, and the running speed of the magnetic tape is 1/2 times that in the normal mode. The track angle at this time is indicated by a ₂ in FIG. 8, whereas during recording, unlike the conventional case, the rotation speed of the rotating drum is set to 1.5 times that in the normal mode, and the tape traveling speed is 1 / Double, 1.5 times of rotating drum
Since to carry out the recording by the rotary head at a rate of once per rotation, the scan vector of the rotary head at that time is shown in 44 in FIG. 9, the track angle is represented by a _3. Here, in FIG. 9, 1.5d is the scanning vector of the rotary head in the still mode, and (1/2) t is 1/2 of the normal mode.
It shows a running vector during double tape running.

Therefore, also in this embodiment, since the relative speed between the head and the tape at the time of reproduction is different from that at the time of recording, the scanning trajectory of the rotary head at the time of reproduction does not coincide with the recording track mark.
Although deviation corresponding to the difference between the track angle a ₂ during recording shown in track angle a ₃ and 8 at the time of reproduction as shown occurs in FIG. 9,
Since the track angle difference (a ₂ −a ₃ ) of this embodiment is smaller than the track angle difference (a ₁ −a ₂ ) of the above-described conventional method, the error of this embodiment is smaller than that of the conventional method. It can be seen that the rate is good.

The above-mentioned difference in the track angle is not only a problem of the pattern but also relates to the reproduction frequency. The smaller the smaller, the closer the reproduction frequency to the recording frequency. It turns out that it is more advantageous than before.

FIGS. 10 and 11 show that the rotational speed of the rotary drum and the running speed of the magnetic tape are respectively 1 / the value in the normal mode.
With respect to tracks T1, T2, and T3 recorded as double, the rotational speed of the rotary drum is set to be the same as that in the normal mode, and the head scanning trajectory when the running speed of the magnetic tape is set to 1/2 of that in the normal mode is reproduced. When one of the two rotary heads, each having a track width 1.5 times that of the recording track, draws a scanning locus indicated by 51 in FIG. 10, the same azimuth angle as its own in the scanning areas 51a and 51b. When the reproduction signal is obtained only from the scanning area 51a of the track T1 and the other rotary head draws the scanning trajectory indicated by 52 in FIG. 11, the scanning of the track T3 of the scanning area 52a and 52b having the same azimuth angle as its own. A reproduction signal is obtained only from the area 52a.

FIGS. 12 and 13 show a track T1 in which the number of rotations of the rotary drum is set to 1.5 times that in the normal mode, and the running speed of the magnetic tape is set to 1/2 times that in the normal mode.
1, the head scanning trajectory of the present embodiment is shown in which the rotation speed of the rotary drum is the same as that in the normal mode and the running speed of the magnetic tape is １ ／ times that in the normal mode, and the reproduction is performed. One of the two rotary heads whose track width is 1.5 times that of the recording track is shown in FIG.
When the scanning locus indicated by 53 is drawn, the scanning areas 53a to 53a
When a reproduction signal is obtained only from the scanning area 53a of the track T11 having the same azimuth angle as that of the self and the other rotary head draws a scanning locus indicated by 54 in FIG. A reproduction signal is obtained only from the scanning area 54a of the track T13 having the same azimuth angle.

As can be seen by comparing FIGS. 10 and 11 with FIGS. 12 and 13, compared to the head scanning trajectory of the conventional recording / reproducing apparatus shown in FIGS. 10 and 11, FIGS. It can be seen that the head scanning trajectory of the second embodiment has a larger scanning area in which a reproduction signal can be obtained from a recording track, and can perform better scanning.

The recording / reproducing system of this embodiment is almost the same as that of FIG. 1. Track patterns recorded at the same track pitch as in the normal mode and adjacent tracks are recorded by rotating heads having different azimuth angles from each other. In the long-time mode, the magnetic tape is controlled to have a running speed that is half the running speed in the normal mode. Therefore, it is necessary to add a double azimuth head or a rotary head for 2-channel recording. Without recording, recording can be performed twice as long as in the normal mode with only two rotating heads.

On the other hand, at the time of reproduction, unlike the case of recording, the rotation speed of the rotary drum is set to be the same as that of the normal mode, and the running speed of the magnetic tape is set to 1/2 of that of the normal mode. The trajectory does not coincide with the recording track trace, but as shown in FIGS. 12 and 13, the recording track trace can be scanned and reproduced more favorably than in the past, and the equalization characteristics in the demodulation circuit and the clock signal PL for extraction
It is not necessary to switch the center frequency of the voltage-controlled oscillator in L, and a demodulation circuit having the same configuration as in the normal mode can be used, so that the configuration can be made at low cost. Also, the recording head records the digital information signal alternately by the rotating heads Ha and Hb at a rate of once every 1.5 rotations.

In the second embodiment, the description has been given assuming that recording and reproduction are performed twice as long. However, the present invention is not limited to this, and it is essentially 2n (where n is an arbitrary natural number) times. When performing long-time recording / reproduction, the tape traveling speed is set to 1 / (2n) times that of the normal mode, and the rotation speed of the rotary drum is set to (2n + 1) / that of the normal mode.
(2n) times, and recording is performed by using two rotating heads alternately at a rate of once every (2n + 1) / 2 rotations of the rotating drum, and during playback, the rotating speed of the rotating drum is the same as in the normal mode, Only the tape running speed may be 1 / (2n) times the normal mode.

[0054]

As described above, according to the present invention,
By using only two rotating heads having different azimuth angles from each other, it is possible to record and reproduce patterns having different azimuth angles of adjacent tracks during recording and reproduction in the normal mode and 2n times long-time mode. Long-time recording and reproduction can be performed with an inexpensive configuration.

According to the present invention, recording and reproduction in the normal mode and the long-time mode of 2n times can be performed using only two rotary heads having different azimuth angles, and the switching of the characteristics of the reproduction circuit is unnecessary. Since a reproduction signal in the long mode can be obtained using the same reproduction circuit as in the normal mode, recording and reproduction in the long mode of 2n times can be performed with a simpler and less expensive configuration. By setting the number of rotations of the drum and the tape running speed to predetermined values, it is possible to perform recording and reproduction with a better error rate than before.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram of an example of a modulation circuit in the modulation / demodulation circuit in FIG. 1;

FIG. 3 is a block diagram of an example of a demodulation circuit in the modulation / demodulation circuit in FIG. 1;

FIG. 4 is a block diagram illustrating an example of a variable equalizer in FIG. 3;

FIG. 5 is a characteristic diagram of one example of FIG. 4;

FIG. 6 is an explanatory diagram of a track angle in a normal mode.

FIG. 7 is an explanatory diagram of a track angle when the number of rotations of the drum is 1/2 times the normal mode and the tape running speed is 1/2 times the normal mode.

FIG. 8 is an explanatory diagram of a track angle when the number of rotations of the drum is the same as that in the normal mode and the tape running speed is の of the normal mode.

FIG. 9 is an explanatory diagram of a track angle when the number of rotations of the drum is 1.5 times the normal mode and the tape running speed is 倍 times the normal mode.

FIG. 10 is a diagram showing a relationship between a head scanning trajectory of one of the rotary heads and a track when the number of rotations of the drum is 1/2 times the normal mode and the tape running speed is 1/2 times the normal mode.

FIG. 11 is a diagram showing the relationship between the head scanning trajectory and the track of the other rotary head when the drum rotation speed is 1/2 times the normal mode and the tape running speed is 1/2 times the normal mode.

FIG. 12 is a diagram showing a relationship between a head scanning trajectory and a track of one rotary head when the drum rotation speed is 1.5 times the normal mode and the tape running speed is 倍 times the normal mode.

FIG. 13 is a diagram showing the relationship between the head scanning trajectory and the track of the other rotary head when the drum rotation speed is 1.5 times the normal mode and the tape running speed is １ ／ times the normal mode.

[Explanation of symbols]

Reference Signs List 10 magnetic tape 11 data input terminal 12 encoder / decoder circuit (recording signal processing means,
(Reproduction circuit) 13 Memory (recording signal processing means) 14 Modulation / demodulation circuit (recording signal processing means, reproduction circuit) 15 Mode identification signal input terminal 16 Switch circuit (recording means) 17 Head switching pulse input terminal 18, 19 Recording / reproduction amplifier 20 Reproduction Data output terminal 22 Formatter (recording signal processing means) 23 Oscillator (recording signal processing means) 28 Digital modulator (recording signal processing means) 32 Variable equalizer (reproduction circuit) 33 Detector (reproduction circuit) 34 Clock signal extraction Phase locked loop (PLL)
(Reproducing circuit) 35 Deformatter (Reproducing circuit) Ha First rotary head Hb Second rotary head

Claims (4)

[Claims] 1. A magnetic tape which is wound obliquely over an outer peripheral side surface of a rotary drum over an angular range of about 180 degrees and travels at a constant speed by two rotary heads provided opposite to the rotary drum by 180 degrees. In a normal mode, in a helical scan type magnetic recording device configured to record a digital information signal by forming a sequential track by using the two rotary heads alternately, the traveling speed of the magnetic tape is set to the normal speed. 1 / mode
(2n) times (where n is an arbitrary natural number) a tape running speed control means, and the rotation speed of the rotary drum is set to (2n +
1) / (2n) times the rotating drum rotation control means; and the two rotating heads are alternately used at a rate of once per (2n + 1) / 2 rotations of the rotating drum to sequentially apply the magnetic tape to the magnetic tape. Recording means for forming a track to record a digital information signal in a long-time mode. 2. A magnetic tape which is wound obliquely over an outer peripheral side surface of the rotary drum over an angle range of about 180 degrees and is run at a constant speed by two rotary heads provided to face the rotary drum at 180 degrees. In the normal mode, the helical scan type magnetic recording / reproducing apparatus has a configuration in which the two rotating heads are alternately used to form a sequential track to record a digital information signal and reproduce the digital information signal. A tape running speed control means for setting the running speed of the tape to 1 / (2n) times (where n is an arbitrary natural number) times that of the normal mode for both recording and playback in the long-time mode; Rotating drum rotation control means for making (2n + 1) / (2n) times the normal mode for both recording and reproduction in the long-time mode; and the frequency of the digital information signal To (2n + 1) / (2
recording signal signal processing means to increase the number of times by n), and the two rotary heads are alternately used at a rate of once per (2n + 1) / 2 rotations of the rotary drum to sequentially form tracks on the magnetic tape. Recording means for recording a digital information signal from the recording signal processing means in a long-time mode, and characteristics are switched as compared with the normal mode, and A reproducing circuit for decoding a digital information signal reproduced by using two rotating heads. 3. The reproducing circuit comprises: a demodulating circuit for demodulating the reproduced digital signal; and decoding means for decoding an output demodulated signal of the demodulating circuit using a memory. 3. The method according to claim 2, wherein a characteristic and a characteristic of a phase locked loop for extracting a clock signal from an output signal of the equalizer are switched between the long time mode and the normal mode, respectively.
The magnetic recording and reproducing apparatus according to claim 1. 4. A magnetic tape which is wound obliquely over an outer peripheral side surface of the rotary drum over an angular range of about 180 degrees and is run at a constant speed by two rotary heads provided opposite to the rotary drum by 180 degrees. In the normal mode, the helical scan type magnetic recording / reproducing apparatus has a configuration in which the two rotary heads are alternately used to form a sequential track to record a digital information signal and reproduce the digital information signal. A tape running speed control means for setting the running speed of the tape to 1 / (2n) times (where n is an arbitrary natural number) times the normal mode for both recording and reproduction in the long-time mode; In the long-time mode recording, the rotation speed is (2n + 1) / (2n) times that in the normal mode, and in the long-time mode reproduction, the rotation speed is controlled to be the same as that in the normal mode. Ram rotation control means; and alternately using the two rotary heads at a rate of once every (2n + 1) / 2 rotations of the rotary drum to form sequential tracks on the magnetic tape to lengthen the digital information signal. Recording means for performing time mode recording; and a reproducing circuit for decoding a digital information signal reproduced from the magnetic tape on which the digital information signal is recorded in the long time mode using the two rotary heads. Magnetic recording and reproducing apparatus.