JP2537908B2 - Rotating head type recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to recording / recording by obliquely forming tracks on a tape such as DAT (Digital Audio Tape Recorder) and VTR.
The present invention relates to a rotary head type recording / reproducing device for reproducing.

2. Description of the Related Art Recently, R-DAT has been used as a rotary head type recording / reproducing device.
(Rotary head type digital audio tape recorder) and 8mm VTR have been commercialized. ATF method (Automatic Track Findin) is used as the tracking method.
g) has been adopted (eg Electronics Life, March 1987 issue, published by Japan Broadcast Publishing Association, P36, Figure 3-1.
1).

An example of the conventional rotary head type recording / reproducing apparatus described above will be described below with reference to the drawings.

FIG. 3 shows the structure of a conventional rotary head type recording / reproducing apparatus. In FIG. 3, 1 is a magnetic tape. Reference numeral 2 is a rotary drum, which is controlled in speed and rotates at high speed. Heads 3a and 3b are mounted at positions symmetrical with respect to the rotation axis of the rotary drum, and are for recording and reproducing signals on the magnetic tape 1. 4 is an electromagnetic conversion unit, which is a head
The signals reproduced by 3a and 3b are amplified, and the waveform is shaped and output as a head reproduction output. Reference numeral 5 denotes a tracking detection circuit, which detects a deviation amount of the head position with respect to the track from the reproduced tracking detection signal and outputs it as a tracking error voltage. An FG (frequency generator) 6 generates a pulse signal having a frequency proportional to the rotation speed of the capstan 9 described later. 7 is a speed control circuit, which detects the speed error of the capstan 9 by the pulse signal from FG6,
Output as speed error voltage. Reference numeral 8 is a speed control means, which comprises an FG6 and a speed control circuit 7. Reference numeral 9 is a capstan as a driving means, and the rotation of the magnetic tape is controlled by adding the speed error voltage and the tracking error voltage to run the magnetic tape.

The operation of the rotary head type recording / reproducing apparatus configured as described above will be described below. FIG. 4 shows the ATF pattern formed on the magnetic tape. In the figure, f ¹ indicates the pilot signal reproduced as crosstalk between adjacent tracks, and f ² and f ³ indicate the positions of the pilot signals on the adjacent tracks. synchronization signal, f ⁴ is the erasing signal, the head traces the track direction of an arrow a in the drawing. The speed control circuit 7 outputs the difference between the rotation speed of the capstan 9 detected from the pulse signal of the frequency proportional to the rotation speed of the capstan 9 from FG6 and the standard rotation speed of the capstan 9 as an error voltage.

Next, the operation of the tracking detection circuit 5 will be described with reference to FIGS. FIG. 5 shows a specific configuration example of the tracking detection circuit 5, and FIG. 6 shows the operation timing of the tracking detection circuit 5 shown in FIG. In FIG. 6, a is a head switching signal (HSW)
, The output of the head 3a is reproduced in the section ta, and the section tb
Then, the output of the head 3b is reproduced. Also, b
Indicates the contact period of each head with the tape. The low pass filter 15 of FIG. 5 extracts the pilot signal from the head reproduction output as shown in FIG. 6c. The detection circuit 16 outputs the envelope of the pilot signal input from the low pass filter to the differential amplifier 20. In the figure, a ¹ , a ² , a ³ and a ⁴ are pilot signals of the tracks traced by the head, b ¹ , b ² , b ³ and b ⁴ are pilot signals of adjacent tracks on the right side in the head traveling direction, c ¹ , c
² , c ³ and c ⁴ are pilot signals of adjacent tracks on the left side in the head traveling direction. The sync signal detection circuit 17 detects the sync signal from the frequency and recording length of the head reproduction output, and outputs the information to the controller 18. When the frequency of the synchronizing signal is detected, the controller generates a sampling pulse (SP1) as shown in FIG. 6d. When the recording length of the sync signal is detected, a sampling pulse (SP2) is generated as shown in FIG. 6e. The envelope detection output of the pilot signal is sampled and held by SP1, and the difference between that value and the pilot signal of the other adjacent track is stored in the differential amplifier 20.
Is output, and this output is sampled and held by and used as a tracking error voltage. FIG. 6f shows the tracking error voltage. The speed error voltage and the tracking error voltage are added to control the rotation speed of the capstan. As a result, the running of the magnetic tape is controlled so that the heads 3a and 3b trace the center of the track.

Problems to be Solved by the Invention However, with the above-mentioned configuration, when tracking a magnetic tape having a so-called poor linearity in which the recording track and the reproducing head locus do not coincide with each other, as shown in FIG. The control time t ² of the capstan due to the tracking error voltage of the termination side pilot signal is longer than the control time t ¹ of the capstan due to the signal tracking error voltage, and the tracking error voltage (V ¹ ) of the pilot signal at the start side is Does not become a head trace in which the tracking error voltage (V ² ) of the pilot signal on the terminal side becomes equal. Therefore, the head does not trace the center of the track on average.

Further, the control system has a load due to a mechanism and an electrical offset of the system, and the tracking error voltage is zero.
However, there is a problem in that the head is controlled so as to trace the position deviated from the center of the track as shown in FIG. 7B.

In view of the above problems, the present invention resets the tracking error voltage so that the control time of the capstan of the tracking error voltage of each of the start side pilot signal and the end side pilot signal becomes equal by a simple configuration, and a reset voltage mechanism is used. Another object of the present invention is to provide a rotary head type recording / reproducing apparatus in which the tape running is controlled so that the head traces the center of the track on the tape by setting the voltage so as to cancel the offset of the circuit system.

Means for Solving the Problems In order to solve the above problems, a rotary head type recording / reproducing apparatus of the present invention comprises a rotary drum having a head for recording / reproducing a signal on a tape-shaped recording medium, and a tape. And a speed control means for controlling the rotational speed of the drive means, and a head for the track by reproducing the tracking detection signals on the start end side and the end side of the track recorded and formed on the tape by the head. A tracking detection circuit that outputs the amount of positional deviation as a tracking error voltage and a signal that is generated at the timing when the output time of the tracking error voltage by the tracking detection signal on each of the start side and the end side of the track on the tape are equal Track with the timing generator and the signal generated by the timing generator. The tracking error voltage reset circuit resets the ringing error voltage to a voltage for canceling the offset of the mechanism or the circuit and adds the voltage to the output of the speed control means and applies it to the driving means.

According to the present invention, with the above-described configuration, signals are generated at timings when the control time of the capstan due to the tracking error voltage of each of the start side tracking detection signal and the end side tracking detection signal becomes equal, and the tracking error voltage causes the mechanism and circuit. Since the head is traced at the center of the track on the tape after the voltage is reset to cancel the offset of the system, it is possible to supply the rotary head type recording / reproducing apparatus with stable control.

Example A rotary head type recording / reproducing apparatus according to an example of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a rotary head type recording / reproducing apparatus in a rotary head type recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a magnetic tape for recording / reproducing signals, and 2 is a rotating drum, which is controlled in speed and rotates at a high speed. Heads 3a and 3b are mounted at positions symmetrical with respect to the rotation axis of the rotary drum, and are for recording and reproducing signals on the magnetic tape 1. 4 is an electromagnetic converter,
The signals reproduced by the heads 3a and 3b are amplified and waveform-shaped to be head reproduction output. Reference numeral 5 denotes a tracking detection circuit, which detects a deviation amount of the head position with respect to the track from a tracking detection signal during reproduction output of the head and outputs it as a tracking error voltage. Reference numeral 6 denotes an FG (frequency generator), which generates a pulse signal having a frequency proportional to the rotational speed of the capstan 9 described later. 7 is a speed control circuit FG6
The speed error of the capstan 9 is detected by the pulse signal from and is output as a speed error voltage. Reference numeral 8 is a speed control means, which comprises an FG6 and a speed control circuit 7. Reference numeral 9 is a capstan as a speed control means, and the rotation speed is controlled by adding the speed error voltage and the tracking error voltage output from the speed control means 9, and the magnetic tape 1 is run by the rotation. Reference numerals 10 and 11 are D-type flip-flops (hereinafter abbreviated as D-FF), 12 are exclusive-ORs (hereinafter abbreviated as EX-OR), and 13 timing generators are D-
Reference numeral 14 composed of FF10 / 11 and EX-OR12 is a tracking error reset circuit, which switches the output according to signals from the tracking detection circuit and the timing generator.

The operation of the rotary head type recording / reproducing apparatus configured as described above will be described below with reference to FIGS. 1, 2, and 5. FIG. 2 shows the operation timing of the ATF servo device constructed in FIG.
W is a switching signal of the heads 3a and 3b and is synchronized with the rotation cycle of the rotary drum 2. In the section ta, the output of the head 3a is reproduced,
In the section tb, the output of the head 3b is reproduced. Further, F indicates the contact period of each head with the tape. FIG. 5 shows the structure of the tracking detection circuit. The low pass filter 15 extracts a pilot signal from the head reproduction output as shown in FIG. 6c. The detection circuit 16 outputs the envelope of the pilot signal input from the low pass filter to the differential amplifier.
Figure ^{a 1, a 2, a 3} , a 4 is a pilot signal of the track which the head is tracing ^{b 1, b 2, b 3} , b 4 is a pilot signal of the adjacent track in the head traveling direction right, c ¹ , c ² , c ³ , and c ⁴ are pilot signals of adjacent tracks on the left side in the head traveling direction. The sync signal detection circuit 17 detects the sync signal from the frequency and recording length of the head reproduction output, and outputs the information to the controller 18. When the frequency of the synchronization signal is detected, the controller 18 performs sampling / sampling as shown in FIG. 2H.
Generates a pulse (SP1). When the recording length of the sync signal is detected, the sampling pulse (SP
2) occurs. The envelope detection output of the pilot signal is sampled and held by SP1, the difference between that value and the pilot signal of the other adjacent track is output by the differential amplifier, and this output is sampled and held by SP2 to be the tracking error voltage. FIG. 2J shows the tracking error voltage. In the timing generator, HSW is input to D-FF10 and punched out by the pulse CLK shown in FIG.
It is output as the output of −FF10. In D-FF11, B is further punched by CLK shown in FIG. 2D and the waveform shown in C is output at the timing shown in the figure. The EX-OR of D and C is taken and the pulse signal generated by HSW switching like EX is EX
Output from OR12 output as tracking error voltage reset signal (SPE). In the tracking error voltage reset circuit 14, the above-mentioned tracking error voltage is input to one of the inputs and a constant voltage V _off is applied to the other. V _off is an offset cancel voltage, which is set to a voltage that cancels the offset of the mechanism or circuit. Tracking error voltage reset circuit
14 switches so that the tracking error voltage is output when SP2 is input and the offset cancel voltage is output when SPE is input. Since the HSW is switched just in the middle of the head contact period, the output time of the tracking error voltage by the start side pilot signal and the end side pilot signal becomes almost equal as shown by t ¹ ′, t ² ′ of K, and the tracking The offset cancel voltage is held while the error voltage is not output. The tracking error voltage generated as described above and output from the tracking error voltage reset circuit is added to the speed error voltage output from the speed control means 8 to control the rotation speed of the capstan 9.

As described above, according to this embodiment, the SPE is generated by switching the HSW, the tracking error voltage is generated at the timing of SP2, and the circuit for resetting the tracking error voltage to the offset cancel voltage at the timing of SPE is provided. As a result, even when a tape having poor track linearity is reproduced, the tracking error voltages due to the pilot signals are equal on the track start side and track end side as shown in FIG. 2L, and the center of the track is headed on average. Traces and the tracking error voltage is 0
At this time, as shown in FIG. 7A, it becomes possible to control the running of the tape so that the head traces the center of the track by the action of the offset cancel voltage.

Although the tracking error reset circuit resets the tracking error voltage to the offset cancel voltage only by the end side pilot signal of the tracking error voltage in the above embodiment, if the output time is the same, both the start side and the end side cancel the offset. It may be reset to the voltage. Further, the switch for switching the tracking error voltage and the offset cancel voltage is provided outside the tracking error detection circuit, but may be provided inside (for example, the output of the differential amplifier). Further, the timing at which SPE occurs is described in the example in which the switching of HSW is taken, but if the output time of the tracking error voltage on the start side and the output time of the tracking error voltage on the end side are equal, Other methods may be used.

As described above, according to the present invention, the length of the output time of the tracking error voltage by the tracking detection signal on the leading end side of the track formed on the tape and the output time of the tracking error voltage by the tracking detection signal on the trailing end side When the tape with bad track linearity is reproduced, the track start side / termination side is provided by providing a tracking error voltage reset circuit that resets at the timing when the values become equal and adds a predetermined DC voltage to the output of the speed control means and applies it to the drive means. It is possible to control the tape running so that the tracking error voltage due to the tracking detection signals on each side becomes equal and the head traces the center of the track on average, and a predetermined DC voltage is applied to the mechanism or the electrical system. Offset canceling By setting the cell voltage, it is possible to obtain the effect that the tape running can be controlled so that the head traces the center of the track when the tracking error voltage is 0. The device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a rotary head type recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an operation waveform diagram thereof, FIG. 3 is a block diagram of a conventional example, and FIG. 4 is recording on a tape. FIG. 5 is a plan view of a recording example of the formed tracking detection signal, FIG. 5 is a block diagram of a specific example of the tracking detection circuit, FIG. 6 is an operation waveform diagram of FIG. 3, and FIG. 7 is a trace of the head in the embodiment. FIG. 1 ... Magnetic tape, 2 ... Rotating drum, 3a, 3b ... Head, 5 ... Tracking detection circuit, 6 ... Driving means, 7
...... Speed control means, 13 ...... Timing generator, 14 …… Tracking error voltage reset circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuyuki Taguchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kazuo Arai, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. Within

Claims (2)

(57) [Claims] 1. A head for recording / reproducing a signal on / from a tape-shaped recording medium, a rotary drum on which the head is mounted and rotating, a drive means for running the tape by rotation, and a drive means for the drive means. A speed control means for detecting the rotation speed and outputting an error from the reference rotation speed as a speed error signal, and a head for reproducing tracking detection signals on the start side and the end side of tracks obliquely recorded and formed on the tape. A tracking detection circuit that detects the head position with respect to the track and outputs the deviation amount of the head position as a tracking error signal, and the length of the output time of the tracking error signal by the tracking detection signal on the start side of the track and the tracking on the end side. The signal is sent at the timing when the output time of the tracking error signal by the detection signal becomes equal. A timing generator for outputting a, by a signal output by the timing generator includes a tracking error signal reset circuit for resetting the tracking error signal to a predetermined level V _OFF, via the tracking error signal reset circuit the tracking error signal A rotary head type recording / reproducing apparatus, wherein the rotary head type recording / reproducing apparatus adds the speed error signal output from the speed control means to the drive means. 2. A tracking error signal reset circuit, when resetting a tracking error signal, sets the level of V _OFF so as to cancel an offset generated by the drive means and the speed control means. The rotary head type recording / reproducing apparatus according to claim 1.