JP2532311Y2 - Magnetic tape playback device - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a magnetic tape reproducing apparatus in which data such as video, audio, and control signals are recorded at an angle to the tape length.
For example, it relates to a video tape recorder and a digital audio tape (DAT).

[Conventional technology]

In general, the reproducing apparatus includes a rotating read head, and a data read speed of the read head is constant from the beginning to the end of the tape. Different command signals are provided over time to produce a rotating speed that varies over time.

For example, at the beginning of winding when most of the tape is wound on the supply reel, the take-side reel rotation is set slightly earlier, and at the end of winding when the supply-side reel has run out of tape, the take-side reel rotation is reduced. It is set to be slower so that the running speed of the tape passing through the reading head is constant.

The above situation is the same in the case of a so-called search operation in which the tape running is rotated forward and backward at a speed faster than the normal reproducing speed in order to detect a desired portion in the tape. (However, the tape speed is not completely constant at the time of search because the tape running speed is much faster than at the time of reproduction, and the rotational speed of the read head is slightly increased or decreased to compensate for the tape speed.) Problems to be Solved] By the way, unlike the above-described search operation, if the desired position can be found accurately, the faster the tape traveling speed is, the more advantageous it is.

On the other hand, the reading speed of the data recorded on the tape
There is a natural limit for each device such as R and DAT.

That is, the relative speed of the data area in which the data is recorded with respect to the read head has a limit speed depending on the model and each product.

However, on the other hand, in a magnetic tape reproducing apparatus that employs a so-called helical scan reading method, the data area recorded on the tape is inclined with respect to the length direction of the tape. The limit speed varies depending on the running direction of the tape.

That is, in the tape (T) in which the data area (E) is formed to the lower right as shown in FIG. 4.5, the tape running in the normal direction shown in FIG. 4 and the tape running in the reverse direction shown in FIG. If the same tape running speed is used when reading the data area of No. 1, the time required for reading in the forward rotation is shorter than that in the reverse rotation. In other words, the fact that the time required for reading one data area is longer in the reverse rotation indicates that there is no problem even if the tape running speed in the reverse rotation is increased. (In FIG. 4.5, the arrows X and Y indicate the reading directions of the reading head, respectively. Since the arrow Y at the time of reverse rotation is in order with respect to the inclination of the data area (E), it corresponds to one data area. Thus, the present invention seeks to minimize the time required for a search operation by utilizing the above fact.

[Means for solving the problem]

The present invention is a magnetic tape reproducing apparatus in which data is recorded obliquely to the tape length and the data is read by a rotating read head. In a magnetic tape reproducing apparatus that performs a search by performing a reverse rotation search, a memory in which a reel rotation number command value for a forward rotation search is stored in a microcomputer control circuit that controls a tape speed, and a reel rotation number command for a reverse rotation search The tape speed at the time of reverse rotation search is set as the tape speed at the time of forward rotation search by setting the memory at which the value is stored, and making the value of the rotation speed command value at the latter memory larger than the rotation speed command value at the former memory. The speed is set to be faster than the speed, and it is set so that the read head has almost the maximum relative speed that the read head can read data on the tape in both forward and reverse searches. That is a magnetic tape reproducing apparatus.

[Action]

At the time of search, the tape is run in either the forward or reverse direction until the desired location is found, but since the tape running speed in the search in the reverse direction is faster than during forward rotation,
The time required for the search operation is reduced on average.

〔Example〕

FIG. 1 shows a schematic configuration of a tape recorder as one embodiment of the present invention, which comprises a reading head unit and a tape driving unit.

The reading head unit includes a rotating drum (1) rotated by a cylinder motor (not shown), a drum servo circuit (2) for keeping the rotation of the cylinder motor at a given given number of rotations, and a rotation from the cylinder motor. Head switching circuit for generating a head switching signal based on a phase signal (3)
And the reproduction signal from the rotating drum (1) is amplified (4)
It has a signal processing circuit (7) which takes in through (5) and a switch (6) and performs predetermined processing, and the switch (6) is switched by a signal from a head switching circuit (3).

The tape drive section includes a supply-side reel (8) and a take-up-side reel (9), a capstan motor (11) for driving these reels (8) and (9), and a rotation of the capstan motor (11). Microcontroller control circuit to control the number (12)
The supply-side reel (8) and the take-up reel (9) are switched by a switching device (not shown) when the tape is switched between normal rotation and reverse rotation.

In the control circuit (12), the above two reels (8)
The difference between the rotation speeds of (9) is detected and both reels (8) (9)
Tape position detecting means (13) for detecting the progress of the winding, that is, the tape amount detecting means (13)
And a rotation speed changing means (14) for changing the rotation speed of the capstan motor (11) based on the data from.

The tape position detecting means (13) is provided for each reel (8) (9)
The sensors (15) and (16) detect the detection pieces provided at equal intervals on the outer periphery of the sensor and generate pulses. By comparing the time intervals of the pulse generation, the rotation speeds of both reels (8) and (9) are determined. , That is, the amount of movement of the tape.

That is, if the pulse interval from the supply reel (8) side is larger than that from the take-up reel (9), the take-up reel (9) is rotating faster. It is detected that the tape is still mostly left on the supply reel (8) side, and it is detected that it is in the early stage of winding, and conversely, the pulse interval from the supply reel (8) side is changed from the winding reel (9) side. If it is smaller than that of, the end of winding is detected.

The rotation speed changing means (14) includes a sensor (17) for detecting the rotation speed of the rotation shaft of the capstan motor (11), and based on a signal from the sensor (17), if the predetermined rotation speed has not been reached. Command a speed increase, and if it has, command a deceleration. The rotation speed changing means (14) receives the tape position information (18) from the tape position detection means (13) and issues different rotation speed command values as follows according to the tape position information. It has become.

That is, as shown in FIG. 2, in the initial winding state in which a large amount of tape still remains on the supply side reel (8) and the rotation speed of the winding side reel (9) is relatively high, the capstan motor The rotation number command value to (11) is set to a large value, and most of the tape moves from the supply-side reel (8) to the take-up reel (9) and is relatively moved to the take-up reel (9). 9)
When the winding speed is low at the end of winding, the rotation speed command value for the capstan motor (11) is set to a small value.

The above description is for the forward rotation in which the take-up reel (9) is driven to rotate. In this example, the rotation speed command value is represented by a hexadecimal number, and B8 <B9 ..., BE <CO, C9
In the case of <CA... CE <DO, the higher the value in FIG. 2 is, the faster the rotation speed given to the motor is.

In accordance with the present invention, the rotational speed command value is set to a different value between the value at the time of normal rotation and the value at the time of reverse rotation (it was the same in the past). It is set to be larger than the value at the time of normal rotation. Therefore, FIG. 2 shows the contents of the memory in the rotation speed changing means (14),
This value can be rewritten later. The right end of FIG. 2 shows the rotation ratio of both reels (8) and (9).

Next, the operation in this embodiment will be described based on a flowchart.

That is, the operator presses a key (not shown) to input a desired position at which the user wants to find the beginning of the tape. The input data is taken into the control circuit (12), and either the take-up reel (8) or the supply reel (9) is driven and rotated by the capstan motor (11) based on the input data.

In this case, the direction in which the tape first starts moving (forward or reverse) may be input simultaneously when the operator performs key-in, or the microcomputer control circuit (12) may be used based on the current state of the tape position and information on the desired position. The determination may be made within the calculation.

In any case, if both reels (8) and (9) start to rotate, the sensors (15) and (16) are turned to each reel (8).
(9) The number of rotations is detected in the form of a pulse time interval, the ratio is determined, and the tape position is detected (step (2)).

Then, the current tape moving direction is determined (step). If the rotation is forward (FF), a rotation speed command value corresponding to the tape position information is entered based on the memory table on the left side of FIG. ), And if it is a reverse rotation (REW), the motor (1) outputs a rotation command value corresponding to the tape position information based on the memory table on the right side of FIG.
Output to 1) (step).

That is, for example, even if the detected value of the tape position (reel rotation ratio) is the same “0.6”, “B9” during normal rotation (FF)
Is output, and "CA" is slightly larger during reverse rotation (REW).
Is output, and a slightly faster tape running speed can be obtained at the time of reverse rotation.

Then, while the tape is running by the forward or reverse rotation, the signal inserted into a predetermined position of the data area of the tape is read by the read head (1),
When the operator reaches a desired position of the cue, the tape travel is stopped.

In addition, the rotation ratio in FIG. 2 can be variously changed,
The one shown in FIG. 2 is not always the optimum value.
Similarly, the rotation command value at the time of forward rotation (FF) and reverse rotation (REW) can be changed. In short, the command value at the time of reverse rotation is changed from the command value at the time of normal rotation by the motor (11) rotation speed. It is set to be large.

Further, the rotation command value may be set to the maximum number of rotations at which the read head can read data in the data area in accordance with the principle described at the beginning based on FIG.

Although only the playback function has been described in the above description, it is needless to say that the present invention can be applied to a playback apparatus having a recording function.

〔effect〕

As is clear from the above description, in the magnetic tape reproducing apparatus according to the present invention, the reverse running speed of the tape particularly during the search is set faster than the running speed during the forward rotation, and as a result, the search speed is averaged. And the time required for the search is reduced. In other words, in a magnetic tape reproducing apparatus having both the forward running search function and the reverse running search function, the forward running search and the reverse running search are considered to be used at almost the same frequency. The average time required for the search is shorter than that of the apparatus having the same tape speed at the time of the reverse rotation search. In addition, since the tape speed at the time of reverse rotation search is set to be higher than the tape speed at the time of forward rotation search, the tape speed should be almost the maximum readable speed in both forward and reverse searches. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a magnetic tape reproducing apparatus according to the present invention, FIG. 2 is a diagram showing the contents of a memory in a rotation speed changing means, FIG. 3 is a flowchart showing an operation, and FIG. FIG. 4 is an explanatory diagram showing a relationship between a data area and a reading direction according to directions. (E): data area, (T): tape, (1): rotating drum, (8): supply side reel, (9): winding side reel, (14): rotation speed changing means (running speed command means) ).

Claims (1)

(57) [Scope of request for utility model registration] 1. A magnetic tape reproducing apparatus in which data is recorded obliquely to a tape length and the data is read by a rotating read head, and the tape is rotated forward at a speed higher than a normal reproducing speed. And a memory in which a microcomputer control circuit for controlling a tape speed stores a reel rotation speed command value for a forward rotation search, and a reel rotation speed for a reverse rotation search in a magnetic tape reproducing device that performs a search by performing a reverse rotation search. A memory in which a command value is stored is provided, and a value of a rotation speed command value in the latter memory is set to be larger than a value of a rotation speed command value in the former memory. The speed is set to be faster than the speed, and it is set so that the read head becomes almost the maximum relative speed at which the read head can read data on the tape in both forward and reverse searches. Magnetic tape reproducing apparatus that.