JPH04358342A - Rotary head type magnetic tape unit - Google Patents

Abstract

PURPOSE:To suppress damage at a minimum even when a tape is stuck to the cylinder drum of the rotary head type magnetic tape unit. CONSTITUTION:Two rotary heads 11-1 and 11-2 carried by a cylinder drum 102 reads information by scanning the surface of a magnetic tape 12 at a prescribed angle, and the information is inputted through a head switching circuit 16 to a reproducing amplifier 13. At circuits following to the reproducing amplifier 13, a prescribed processing is executed. On the outer peripheral face of a rotor to be rotated integrally with the cylinder drum 102, magnets are provided at regular intervals and with the rotation, an FG signal in a cycle T1 is outputted from a hole sensor, which is provided in counter to this rotor, to a rotation monitor circuit 17. The rotation monitor circuit 17 monitors the cycle, judges it when this cycle is higher than a prescribed value that the tape is stuck and outputs a cylinder drum stop signal 30 to a drive control circuit 20.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head magnetic tape device for recording and reproducing digital information such as music on a magnetic tape using a head carried on a cylinder drum.

0002

2. Description of the Related Art Devices for digitally recording data on predetermined tracks of magnetic tape have been put into practical use, such as R-DAT (
known as a rotary digital audio tape recorder) system. Unlike conventional analog recording, this digital magnetic tape device suffers little signal deterioration during recording and playback, allowing for high-density recording, as well as easy follow-up recording, high-speed searches using subareas, and various editing operations such as song selection. It has the advantage of being able to Therefore,
Such a digital magnetic tape device is based on the above-mentioned R-D.
It can be applied not only to audio recording like AT, but also to recording and reproducing graphics and other digital data.

Now, in a digital magnetic tape device such as R-DAT, as shown in FIGS. 6(A) and 6(B), a rotating head is normally scanned diagonally with respect to a running magnetic tape. A so-called helical scan method is used. In this figure, the magnetic tape (12) is a cylindrical cylinder drum (102) with a rotating shaft (105) slightly inclined with respect to the direction perpendicular to the tape running direction.
supply reel (14) while contacting the supply reel at a 90 degree wrap angle.
From there, it is sent to a take-up reel (15). Two magnetic heads (11-1) and (11-2) are provided on the circumferential surface of the cylinder drum (102), facing each other at 180 degrees, and are arranged on the magnetic tape (12) in the tape running direction (11-2).
07), a long straight track is formed that is slightly inclined with respect to 07). With this configuration, it is possible to ensure stable tape running while ensuring contact between the magnetic tape and the head, and the use of a large diameter drum has the advantage that the rotational speed of the rotating head can be relatively low. be.

In such a helical scan method, a track on a magnetic tape generally includes a PCM (main) area for digitally recording data and a subarea for digitally recording a subcode signal indicating the characteristics of this data. The magnetic tape has a tape format consisting of the following, and predetermined data recording is performed by continuously forming tracks on the magnetic tape.

FIG. 7 shows tracks formed on a magnetic tape (12). As shown in this figure, on the magnetic tape (12), there is a tape running direction and an angle θ.
The tracks (114) are continuously formed in such a manner that the tracks (114) are formed in a continuous manner. Each track consists of a PCM area (115) provided in the center, an ATF (auto track following) area (116) provided on both sides of the PCM area, and subareas (117) provided on both sides of the PCM area (115). Ru. Of these, the PCM area (115) is an area where the main signal as song data is recorded, and the ATF area (11
6) is an area where information necessary for tracking is recorded, and a subarea (117) is a program number indicating the song number, a start code signal (hereinafter referred to as start ID) indicating the start position of the main signal, and a priority. This is an area where code signals, playback time information, etc. are recorded. Each song data (hereinafter simply referred to as a program) is managed by the subcode signal of the subarea provided in each track, and the program number is assigned to the sub area of the required track for each section of data. The songs are written in the areas one after another, and the desired program can be selected by sequentially searching these areas. In addition, a random high-speed search is also possible in cooperation with a program memory that stores these recording orders.

The start code signal is called a start ID and is one of the most important subcode signals. This start ID is usually recorded for 9 seconds at the beginning of the song and is used during playback or high-speed search. For example, when this signal is detected during normal playback, a start indicator lamp provided on the operation panel, for example, lights up during that time to indicate that the beginning of the song is being found.

[0007]

However, in such a rotating head type magnetic tape device, like other precision machines, there is a problem associated with so-called dew condensation. This occurs, for example, when a device that has been left in a low-temperature atmosphere for a long time is suddenly moved to a hot and humid environment, and condensation forms on the surface of each functional element, causing various problems. . One of these problems is the problem of tape sticking to the cylinder drum. Although this is not caused solely by dew condensation, it is particularly likely to occur when dew condenses on the surface of the cylinder drum. For this reason, conventional rotating head type magnetic tape devices have taken measures such as constantly heating important parts inside the device, but this is not always sufficient, and sometimes the tape sticks to the cylinder drum, making it difficult to use just the tape. However, there was a problem in that the equipment side also suffered fatal damage.

[0008]Therefore, there is a problem that the above problems must be solved.

[0009] The present invention has been made to solve this problem, and even if the tape sticks, the
It is an object of the present invention to provide a rotating head type magnetic tape device that can minimize damage caused by this.

0010

[Means for Solving the Problems] A rotary head type magnetic tape device according to the invention as claimed in claim 1 scans a magnetic tape with a head supported on a rotating cylindrical cylinder drum to record digital music such as musical pieces. A device for recording and reproducing program information and various subcode information, which (i)
a detection means for detecting a value corresponding to the rotation period of the cylinder drum; (ii) a comparison means for comparing a value detected by the detection means with a predetermined value set in advance; and (iii) a result of comparison by the comparison means. and a control means that determines that the magnetic tape is stuck to the cylinder drum when the detected value exceeds the predetermined value, and performs predetermined control regarding the rotation of the cylinder drum.

A rotary head type magnetic tape device according to a second aspect of the invention is the rotary head type magnetic tape device according to the first aspect, in which the period of the head switching signal is used as the value corresponding to the rotation period of the cylinder drum. It is something.

A rotary head type magnetic tape device according to a third aspect of the invention is the rotary head type magnetic tape device according to the second aspect, in which the predetermined value to be compared is set to 120 milliseconds.

[0013]

[Operation] In the rotating head type magnetic tape device according to the present invention, a value corresponding to the rotation period of the cylinder drum is detected, and when this value exceeds a predetermined value, it is determined that the magnetic tape is stuck to the cylinder drum. By doing so, it becomes possible to detect tape sticking to the cylinder drum at an early stage.

[0014]

EXAMPLES The present invention will be explained in detail with reference to Examples below.

FIG. 1 shows the main parts of a rotary head type magnetic tape device according to an embodiment of the present invention.

2 carried on the cylinder drum (102)
The two rotating heads (11-1) and (11-2) are configured to helically scan the magnetic tape (12) while in contact with the magnetic tape (12) at a predetermined angle with respect to its running direction. . The drive unit (19) has a configuration as shown in FIG. 6, but is shown here in a simplified manner.

The running of the magnetic tape (12) is controlled by a drive motor (not shown), and each track (114) (
FIG. 7) is scanned alternately by two rotating heads (11). Thereby, read signals from the rotary heads (11-1) and (11-2) are input to the head switching circuit (16) every half rotation of the cylinder drum (102). This head switching circuit (16) includes a rotation monitoring circuit (17).
) is supplied with a head switching signal (28), and based on this signal, the read signals from the two rotary heads are separated and input to the reproduction amplifier (13). The head switching signal (28) is sent to the head switching circuit (
16), playback amplifier (13) and digital signal processing (
22) is also supplied.

[0018] The cylinder drum (102) of the drive unit (19)
) and the rotation of a tape reel (not shown) are controlled by a drive control circuit (20) that operates based on instructions from a microcomputer (27). This drive control circuit (20) receives a cylinder drum stop signal (30) from a rotation monitoring circuit (17) when a predetermined condition is met.
is now entered.

Now, the signal amplified by the reproduction amplifier (13) (FIG. 1) is subjected to equalization processing by the equalizer (21) after demodulation, and then input to the digital signal processing circuit (22). The reproduced signal input to the digital signal processing circuit (22) is subjected to predetermined signal processing, and the digital output terminal (
In addition to being directly output as a digital signal from 23), D
Analog output terminal (25) via /A converter (24)
output as an analog signal.

A subcode detection section (26) is connected to this digital signal processing circuit (22), detects various subcode signals from the reproduced signal input to the digital signal processing circuit (22), and detects various subcode signals from the reproduced signal inputted to the digital signal processing circuit (22). 27). Microcomputer (27)
Based on the instructions input from the operation panel (33),
In addition to controlling operations such as playback, recording, and high-speed search, and selecting various playback modes, it also controls the display control unit (31) based on the subcode signal detected by the subcode detection unit (26), Information such as the program number being searched and the elapsed playback time is displayed on the display (32). Also, this microcomputer (27)
A memory (29) is connected to which stores various programs and data related to playback and recording operations.

FIG. 2 shows the cylinder drum (1) in FIG.
02) and the inside of the rotation monitoring circuit (17).

In this figure, the cylinder drum (102) is
It rotates together with a rotor (42) using a rotating shaft (41) as a rotating axis. Rotor (42
) A magnet (44) having a predetermined number of teeth is regularly arranged on the outer peripheral surface of the magnet (F
(requency Generator) signal (45)
is output and input to the timer (51) of the rotation monitoring circuit (17). The output side of this timer (51) is connected to one input terminal of a comparator (52). Reference data (53) is input to the other input terminal of this comparison section (52). The output of the comparing section (52) is input to a determining section (54), and this determining section (52) further outputs a cylinder drum stop signal (30).

Furthermore, a single magnet (46) is supported at one location on the outer peripheral surface of the rotor (42), and its rotational position is detected by a Hall sensor (47) provided opposite to the magnet (46). It has become. This Hall sensor (4
7) outputs a detection signal (48) for each rotation of the rotor, and is input to the processing circuit (58) via the amplifier (57) of the rotation monitoring circuit (17). This signal is processed by the processing circuit (58) as a head switching signal (
28).

In this embodiment, the number of teeth of the magnet (44) is "24", and the rotation speed of the cylinder drum (102) during normal tape playback is 2000 rpm. Therefore, the frequency f1 and period T1 of the FG signal (46) are:
The frequency is 800Hz and 1.25ms, respectively. Also, the time T required for one rotation of the cylinder drum (102) (hereinafter referred to as
This is called the rotation period. ) is 30ms. Further, in this case, the period of the detection signal (48) from the Hall sensor (47) is equal to the rotation period of the cylinder drum (102), which is 30
ms.

The operation of the rotary head type magnetic tape device configured as above will be explained. The FG signal (46) output from the Hall sensor (43) is input to the timer of the rotation monitoring circuit (17) as a waveform as shown in FIG. 3(a).
Here, the period T1 is measured based on a predetermined clock signal (not shown) and inputted to one input terminal of the comparator (52). This comparison section (52) performs a comparison with reference data (53) input to another input terminal, and outputs the comparison result to a determination section (54). Judgment part (54)
, the period T1 of the FG signal (46) is the reference data (53
), it is determined that an abnormality has occurred in the rotation of the rotor (42), that is, the cylinder drum (102), and a cylinder drum stop signal (30) is output to the drive control circuit (20) (Fig. 1). . For example, a cylinder drum (1
When tape sticking occurs due to dew condensation in step 02), the rotational speed of the cylinder drum (102) decreases and its rotation period becomes longer. When this rotation period reaches T2 and exceeds the reference data (53), for example as shown in FIG. 3(b), a cylinder drum stop signal (30) is output. As a result, the drive control circuit (20) stops sending the drive signal to the direct drive motor and operates a brake (not shown) to suddenly stop the cylinder drum (102). Thereby, wrapping of the tape can be minimized and damage to the tape and the device can be reduced.

In this embodiment, a special circuit for monitoring the FG signal (46) is provided, but instead of providing such a circuit, for example, a microcomputer (
This can also be realized using the so-called key scan operation of 27). However, in general, the key scan period of the microcomputer (27) is long, about 7 ms, so the FG signal (4 ms) has a short period of 1.25 ms.
6) cannot be monitored. Therefore, in this case, rotation monitoring is performed using the head switching signal (28) output from the processing circuit (28) instead of the FG signal (46). This head switching signal (28) is, as shown in FIG.
The period T is the rotation period of the cylinder drum (102) 30
Equal to ms. Therefore, this head switching signal (28) may be directly input to the microcomputer (27) and monitored by its key scan function. The monitoring operation of the microcomputer (27) in this case will be explained with reference to FIG.

The microcomputer (27) uses the key scan function to check the level (H, L) of the head switching signal (28) every 7 ms, and calculates the period T (
FIG. 5 step S101). As a result, when the period T exceeds a predetermined value (step S102; Y), it is determined that the tape has stuck to the cylinder drum (102) (step S102; Y).
103), predetermined control is performed (step S104). In other words, the cylinder drum stop signal is sent to the drive control circuit (2
0), and performs control such as stopping the cylinder drum (102) or further rotating the cylinder drum (102) in reverse.

However, in the fast search (FF) mode in the playback direction, it is necessary to increase the rotation speed of the cylinder drum (102) in order to synchronize the rotary head (11) with the tape speed, and the rotation period is about 15 ms. On the other hand, in the reverse high speed search (FR) mode, it is necessary to lower the rotation speed of the cylinder drum (102), and the rotation period is about 60 ms. Therefore, 70~
If approximately 80 ms is set as the boundary value for determining tape adhesion, there is a risk of erroneous determination. Therefore, as a result of conducting experiments taking various conditions into consideration, it was found that a value of about 120 ms is safe. If this value is set as the boundary value, even in FR mode, it will not be mistakenly determined that tape sticking has occurred, and when the tape actually sticks, it will be ensured that the rotation is more than the rotation of the cylinder drum (102). This means that it can be detected.

[0029]

[Effects of the Invention] As explained above, according to the present invention,
By detecting a value corresponding to the rotation period of the cylinder drum and determining that the magnetic tape has stuck to the cylinder drum when this value exceeds a predetermined value, it is possible to detect tape sticking to the cylinder drum at an early stage. Detection becomes possible. This has the effect of minimizing fatal damage caused when the tape sticks.

Further, according to the invention as set forth in claims 2 and 3, since the head switching signal is used as a value corresponding to the rotation period of the cylinder drum, the microcomputer can be equipped without providing a special circuit. This has the advantage of being able to detect tape sticking using existing functions such as key scanning.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of a rotary head type magnetic tape device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing in detail the cylinder drum, its surroundings, and a rotation monitoring circuit of this rotary head type magnetic tape device.

FIG. 3 is a waveform diagram showing the waveform of an FG signal.

FIG. 4 is a waveform diagram showing the waveform of a head switching signal.

FIG. 5 is a flowchart showing the operation of monitoring head switching signals by a microcomputer.

FIG. 6 is an explanatory diagram showing the arrangement relationship between a cylinder drum and a magnetic tape in a magnetic tape reproducing device.

FIG. 7 is an explanatory diagram showing a recording format of a magnetic tape played back by a magnetic tape playback device.

[Explanation of symbols]

(11-1), (11-2) Rotating head (12)
Magnetic tape (17) Rotation monitoring circuit (19) Drive section (20) Drive control circuit (22) Digital signal processing circuit (26) Subcode detection section (27) Microcomputer (43), (47) Hall sensor (44) , (46) Magnet (51) Timer (52) Comparison section (54) Judgment section (58) Processing circuit (102) Cylinder drum (114) Track (115) PCM area (116) ATF area (117) Sub area

Claims (3)

[Claims] 1. A device for recording and reproducing digital program information such as musical pieces and various subcode information by scanning a magnetic tape with a head carried on a rotating cylindrical cylinder drum, the cylinder drum being a detecting means for detecting a value corresponding to the rotation period of the detector; a comparing means for comparing the detected value by the detecting means with a predetermined value; and as a result of the comparison by the comparing means, the detected value is determined to be the predetermined value. 1. A rotary head type magnetic tape device characterized by comprising: control means for determining that the magnetic tape is stuck to the cylinder drum when the rotation of the cylinder drum exceeds the above limit, and for controlling the rotation of the cylinder drum in a predetermined manner. 2. The rotary head type magnetic tape device according to claim 1, wherein a period of a head switching signal is used as a value corresponding to a rotation period of the cylinder drum. 3. The rotary head type magnetic tape device according to claim 2, wherein the predetermined value is set to 120 milliseconds.