JPS6151328B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention automatically adjusts the installation angle of the playback head to the optimum value during playback, in order to faithfully playback information already recorded on a magnetic tape. This invention relates to a head angle adjustment device that can reproduce faithfully up to high frequency ranges.

(b) Conventional technology Even if the tape speed, equalizer characteristics, etc. of a tape recorder are standardized, if the head mounting angles during recording and playback are different, faithful playback cannot be achieved, especially in the high frequency range. The gain at will decrease.

For this reason, as described in Japanese Patent Publication No. 52-6162, a tape on which a standard signal has been recorded is used and the head angle is adjusted to be optimal while reproducing the standard signal.

(c) Problems to be solved by the invention Conventionally, it was necessary to use a tape on which a standard signal was recorded to adjust the head angle, so if the standard tape was not available, the head angle could not be adjusted. . Furthermore, since the head angle differs somewhat depending on the tape cassette used, it may not be possible to adjust the head angle to the optimum one for the tape being used if a standard tape cassette is used.

Therefore, the present invention provides a tape recorder having at least two or more heads, such as a head for recording and playback, in which the two heads are spaced apart from each other in the tape running direction, and the same head as that recorded on the tape is provided. The information is reproduced by the two heads, the ratio of the outputs obtained by the reproduction is calculated, and the difference between the ratio obtained by the calculation at that time and the difference obtained by the calculation immediately before that is calculated, and the To provide a head angle adjusting device which allows the head angle to be adjusted correctly by stopping the angle adjustment when the difference in ratio becomes minimum.

(d) Embodiment An embodiment of the head angle adjusting device of the present invention will be described. In FIG. 1, 1 is a tape, and a first
A head 2 and a second head 3 are provided. 4
is a changeover switch that changes the output of the first head 2 and the second head 3, and after the information S recorded on the tape 1 has been played back for Δt time in the first head 2, the information S is transferred to the second head 3. The output side of the first head 2 is switched to the output side of the second head 3 by the time the signal is reproduced for a time Δt. 5 is an amplifier circuit connected to the changeover switch 4, 6 is a filter, 7 is a sampling hold circuit that samples the signal of time Δt that has passed through the filter 6, and 8 is an A-D that converts the signal into a digital signal. a conversion circuit; 9 is the A-D conversion circuit 8;
10 is a drive circuit driven by a pulse signal obtained from the logic circuit 9. 11 is a head angle adjustment mechanism. The drive circuit 10 and head angle adjustment mechanism 11 are connected to a stepping motor 13 attached to a chassis 12, as shown in FIG.
A second head 3 is provided, one leg 14 is fixed to the chassis 12, and the other leg 1 is fixed to the chassis 12.
Reference numeral 5 comprises a head stand 16 which is threaded and rotated by the stepping motor 13 to adjust its height.

Next, the operation of the device of the present invention will be explained. To adjust the head angle, the first step is to find a correction coefficient Km that represents the difference in output when the same information on the tape is played back by the first head 2 and the second head 3, and After recording the memory data that was reproduced, and then adjusting the head angle of the second head 3, the second head 3 reproduces the same information that was reproduced in the first head 2 and observes changes in the signal size. and a second process of adjusting the head angle. To do this, first drive the tape 1, and then drive the tape 1.
The information signal _S1 recorded in the first head 2 is reproduced for a time Δt. The output _a1 is sequentially supplied to an amplifier circuit 5, a filter 6 and a sampling hold circuit 7 through a changeover switch 4.
It enters the A-D conversion circuit 8. The signal is converted into a digital signal by the A/D conversion circuit 8 and stored in the memory M _A section of the theoretical circuit 9. Next, after /V time (where V is the tape speed), the changeover switch 4 is switched to the side opposite to that shown in the figure, so that the same information _S1 as described above is transmitted from the second head 3 for a time Δt. Reproduce. The output b ₁ passes through the changeover switch 4, and is further supplied to the A/D converter circuit via the amplifier circuit 5, filter 6, and sampling hold circuit 7 as described above, and is stored in the memory M _B section of the logic circuit 9, and is then used for calculation. The signal a ₁ stored in the memory M _A section
A comparison operation is performed with . The ratio a ₁ /b ₁ =K ₁ at that time is recorded in the memory M _K section and used as a correction coefficient for the signal outputs of the first head 2 and the second head 3 in the next second process. Thereafter, as a second step, the changeover switch 4 is again switched to the state shown in the figure, and the information _S2 recorded on the tape 1 is reproduced in the first head 2 for a time Δt to obtain an output _a2 . The output _a2 passes through the amplifier circuit 5, etc.
- added to the D conversion circuit 8, and the A-D conversion circuit 8
The signal a1 is converted into a digital signal and recorded in the memory M _A section of the logic circuit 9 in place of the signal _a1 . At the same time, the difference between the signal _a2 recorded in the memory M _A section and the signal _b1 stored in the memory M _B section is determined, and a signal corresponding to the difference is supplied to the drive circuit 10,
The angle of the second head 3 is adjusted by rotating the stepping motor 13 clockwise or counterclockwise to move the head stand 16. At this time, the time required for the operation of rotating by a certain angle needs to be shorter than (/V-Δt).

Next, after /V time from the time when the first head 2 starts sampling the information S ₂ , the changeover switch 4 is switched to the side opposite to that shown in the figure, and the information S ₂ is transferred to the second head 3 .
is played and gets the output b ₂ . The output is stored in the memory M _B section through the same process as described above. Furthermore, the logic circuit 9 compares and calculates the signals stored in the memory M _A part and the memory M _B part, and calculates a correction coefficient as described above.
Find a ₂ /b ₂ = K ₂ and find the difference from the above correction coefficient K ₁ d = a ₂ /b ₂ - _{a 1} /b ₁ = K ₂ - K ₁ And if the result of the calculation is positive If so, it indicates that the direction of the moved stepping motor approaches the correct angle for the second head. Conversely, if d is negative, this indicates that the moved stepping motor is further away from the correct head angle for the second head. Then, in the first process, the Δt time information _S3 is reproduced again in the first and second heads, and the result is calculated in the logic circuit 9, and in the second process, the stepping motor adjustment process is performed. To repeat, if d is positive in the previous cycle, the motor is rotated in the same direction in this second process. Such operations are repeated until the value of d becomes close to zero. When the value of d becomes close to zero, it means that the reproduction output of the second head 3 is at its maximum, that is, the head angle of the second head 3 has been adjusted correctly, and therefore the angle adjustment is completed.

(e) Effects of the invention As described above, the head angle adjusting device of the present invention has the following features:
A first head and a second head are provided apart from each other in the tape running direction, the same information that is reproduced by the first head is reproduced by the second head, and the obtained information is stored and operated by a logic circuit. And then the first
Before the information reproduced by the head reaches the second head, the head angle of the second head is adjusted to an arbitrary direction, and the same information is reproduced by the second head, and the ratio of the reproduction output of the first head and the second head is adjusted. Since the correct direction for adjusting the head angle is determined from the difference, the head angle can be easily and accurately automatically adjusted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the head angle adjusting device of the present invention, and FIG. 2 is a side view of the head angle adjusting device of the present invention. DESCRIPTION OF SYMBOLS 1... Tape, 2... First head, 3... Second head, 4... Selector switch, 8... A-D conversion circuit, 9
...Logic circuit, 13...Stepping motor.

Claims (1)

[Claims] 1 first and second heads provided apart from each other with respect to the tape running direction;
a changeover switch that switches between the first and second heads so that the same information signal reproduced by the head is applied to the amplifier circuit; a logic circuit that stores and compares the information signals sequentially applied to the amplifier circuit; and an adjustment device that adjusts the angle of the second head using a signal obtained from a logic circuit, the adjustment device is driven to adjust the angle of the second head, and the logic circuit reproduces the data on the first head. The ratio of the signal reproduced by the second head to the signal reproduced at each angle is calculated sequentially, and the difference between the ratio calculated at that time and the ratio calculated immediately before that is calculated, and the difference between the ratios is calculated. A head angle adjusting device characterized in that the angle adjustment is stopped when the angle becomes a minimum.