JP3291942B2 - Magnetic recording / reproducing apparatus and recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking device for a helical scan type magnetic recording / reproducing device, and more particularly to a method for detecting and generating a pilot signal of a recording / reproducing system using pilot signals of four frequencies.

[0002]

2. Description of the Related Art In a helical scan type magnetic recording / reproducing apparatus, tracking control is performed so that a magnetic head traces a recording track formed obliquely on a magnetic tape during reproduction. There are several tracking methods depending on the tracking error detection method.
ATF (Automatic Tracki) using a pilot signal adopted in mmVTR, DAT, etc.
ng Finding) method. For example, 8mmVT
In R, the pilot signals (f1
≒ 6.5fH = 102.5kHz, f2 ≒ 7.5fH = 1
18.9 kHz, f3 ≒ 10.5 fH = 165.2 kHz
z, f4 ≒ 9.5 fH = 148.7 kHz, where fH is the horizontal scanning frequency) is recorded cyclically for each track as shown in FIG. In the figure, reference numerals 2 and 3 denote magnetic heads, and 7 denotes a magnetic tape. At the time of reproduction, a crosstalk component of pilot signals of both adjacent tracks of the track to be scanned is f due to balanced modulation of the reproduced pilot signal and a reference signal having the same frequency as the pilot signal recorded on the track to be scanned.
Extracted as H or 3fH components. Using this, the tracking control is performed by controlling the transport speed of the tape so that the level of the crosstalk component from both adjacent tracks becomes equal.

[0003] Rotation of a pilot signal at the time of recording is defined in a standard, and the azimuth (+ or-) of the head must correspond to the frequency of the pilot signal to be recorded among the four frequencies. In case of 8mm VTR,
The pilot signals of the track written by the −azimuth head are f1 and f3, and the + azimuth heads are f2 and f4. Since the correspondence with azimuth can be determined from the rotation phase of the cylinder, the pilot signal can be made compatible without providing any special means. However, when performing so-called continuous recording in which recording is continuously performed on the already recorded portion, if the rotation of the pilot signal is disturbed at the connected portion, there is a problem that tracking is lost during reproduction and the video and audio are disturbed. Processing to make the rotation of the pilot signal continuous is necessary even in the part. For example, prior to recording, the recorded part is reproduced, and at this time, the rotation of the reference signal for balanced modulation is determined in advance, the tracking is adjusted to this, and the recording is shifted to the recording while maintaining the rotation. Continuity.

[0004]

Although the outline of the tracking control of the pilot signal system has been described above, it is not always necessary to use the pilot signal even if the pilot signal is recorded, and the tracking control is realized by other means. You can adopt it if you can. For example, it is also possible to perform tracking control by detecting the level of a reproduction signal and controlling the tape feed so that the level becomes the maximum level. In this case, a pilot signal is unnecessary, but in consideration of compatible reproduction with another VTR of the same recording method, a pilot signal must be recorded at the time of recording. With the tracking control means using the pilot signal as described above, it is possible to uniquely determine the rotation of the pilot signal. However, when a tracking method that does not use a pilot signal is employed, some detection means is required.

As a method of detecting a pilot signal, for example, in an apparatus disclosed in Japanese Patent Laid-Open Publication No. 60-150256, the frequency of f1 to f4 is set as a pass band for the purpose of shortening the tracking pull-in time at the start of reproduction. A band-pass filter is provided, a pilot signal of a track being reproduced is determined by comparing outputs from each other to find a signal of the maximum level, and a pull-in time is shortened by matching the rotation of the pilot signal to this. If this technique is applied to detect the rotation of the pilot signal, the following problem occurs. The difference between the frequencies of the pilot signals is about 10% as described above. To extract the difference, a bandpass filter having a very high frequency selectivity (Q) is required, which is disadvantageous in terms of the number of components. Further, the amplitude level of the reproduced pilot signal is a small signal of about -14 dB with respect to the color signal, and there is a problem that erroneous detection due to noise easily occurs. The above-mentioned known technique is a discrimination used in a reproduction system, and even if the discrimination is erroneous and the pull-in of tracking is delayed, there is no effect on recording. However, in the case of the recording operation to which the present invention is applied, there is a problem that if the discrimination is wrong, the reproduced image is always disturbed at the portion where the recording is continued as it is.

Accordingly, an object of the present invention is to provide a VTR of a recording system for recording a pilot signal for tracking, and to use a frequency of a pilot signal recorded on a reproduction track even when a tracking system not using a pilot signal is employed. It is an object of the present invention to provide a device which can accurately detect the signal, record the pilot signal without disturbing the rotation of the pilot signal in the joint recording portion, and do not disturb the tracking in the joint portion in the compatible reproduction.

[0007]

To achieve the above object, according to the solution to ## in the case of a continuously spliced to a recorded portion of the recording medium, cyclically generates a pilot signal of a plurality of frequencies
Means for generating a pilot signal,
Record recording pilot signal generated by raw means
Means for reproducing the pilot signal from the recording medium.
Reproducing means connected to the reproducing means and the reproduced pie
Second or higher order gains with different gains depending on the frequency of the lot signal
Filter means having a multi-pass filter characteristic;
Detecting pilot signal frequency from output of filter means
Detecting means, connected continuously to a recorded portion of the recording medium.
The pilot signal circulation order is continuous in the recording
The reproduced pilot signal by the detecting means.
Control the pilot signal generating means according to the frequency of the signal
And control means for performing the control .

[0008]

The pilot signal is extracted from the reproduced signal by the first filter means and the amplifier, and the pilot signal is passed through the second filter means having an attenuation characteristic in the pilot signal band. Can be provided. For example, if the filter is configured by a third-order low-pass filter, the slope of the attenuation in the attenuation range is about 18 dB /
It becomes an octave, and a difference of about 12 dB occurs between the pilot signals of f1 and f3. Further, the amplitude is converted to a DC level by performing envelope detection by peak detection. In the state where the tracking is performed, for example, the signal reproduced by the -azimuth head is a pilot signal of f1 or f3.
Compare the signals of the two tracks operated by the head,
Since the track having the higher level can be determined to be the track on which the pilot signal of f1 is recorded, the rotation of the pilot signal generated in accordance with the track can be set to make the rotation of the pilot signal continuous at the joint shooting portion. it can.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1 is a configuration diagram of a first embodiment of the present invention. Reference numeral 1 denotes a rotary cylinder and a cylinder motor. Based on speed and phase information from the cylinder motor 1, a cylinder motor rotation control circuit 21 controls the motor to rotate at a predetermined speed and phase via a cylinder motor drive circuit 22. Control. Here, the speed information uses a signal having a frequency proportional to the rotation speed of the rotary cylinder 1 (hereinafter, referred to as a DFG signal), and the phase information uses a signal synchronized with the rotation phase of the rotary cylinder 1 (hereinafter, referred to as a DPG signal). I do. The rotation phase control during recording is controlled so that the vertical synchronization signal of the recording video signal input from the recording signal processing circuit 12 and the rotation phase of the cylinder become a predetermined phase. Performs phase control with the generated reference phase signal.

The magnetic tape 7 is transferred by pressing the magnetic tape 7 with a capstan shaft 5 mounted on a concentric shaft of the capstan motor 4 and a pinch roller 6 and rotating the capstan motor 4. The rotation of the capstan motor 4 is controlled by a rotation speed control circuit 32 via a capstan motor drive circuit 33 so as to reach a predetermined rotation speed based on the speed information from the rotation speed detector 31. At the time of reproduction, in addition to rotating at a predetermined speed, tracking control is performed to control the tape position so that the magnetic head scans the recorded track. This is performed by adding a tracking control signal to a motor control signal so as to obtain a predetermined tape phase based on the tracking deviation information, and accelerating and decelerating the tape transfer speed.

Reference numeral 11 denotes an input terminal for video and audio signals;
Is a recording signal processing circuit, which converts an input signal into a signal for recording by processing such as modulation, and records the signal on the magnetic tape 7 by the magnetic heads 2 and 3 via the recording amplifier 13. Further, a synchronizing signal is separated from the input video signal, and the reference signal is used as a reference signal for controlling the rotation phase of the cylinder 1.
Supply to Reference numeral 15 denotes a switch for switching between the magnetic heads 2 and 3, which is a switch control signal synchronized with the rotation phase generated by the cylinder motor rotation control circuit 21 (the frequency is about 30 Hz in the case of the NTSC system;
30). Reference numeral 41 denotes a pilot signal generator which divides the frequency of a source clock having a frequency which is a common multiple of each frequency (for example, 378 fH in the NTSC system) in the case of a pilot signal of four frequencies, and sets the frequency division ratio for each track (field) Generated by switching sequentially. The division ratios are f1: 58, f2: 50, f3: 3
6, f4: 40. The generated pilot signal is suppressed by a low-pass filter 45 to suppress harmonic components.
At 4, it is added to the recording signal from the recording signal processing circuit 12 and recorded on the magnetic tape 7.

During reproduction, a reproduction signal from a magnetic head is amplified by a reproduction amplifier 16 and a reproduction signal processing circuit 17 obtains video and audio reproduction signals. Reference numeral 14 denotes a switch for switching between recording and reproduction, and reference numeral 18 denotes an output terminal for video and audio.
Reference numeral 34 denotes an envelope detection circuit which generates an envelope (envelope) signal of the output signal of the reproduction amplifier 16. 35
Is a tracking control circuit, comprising: means for generating a signal for accelerating or decelerating the rotation speed by a predetermined amount; means for switching between acceleration and deceleration; means for storing the level of the envelope signal; and level comparing means. . 36 is an adder for the motor control signal of the rotation speed control circuit 32 and the acceleration / deceleration signal of the tracking control circuit 36. The tracking control accelerates / decelerates the capstan motor, compares the envelope levels before and after acceleration / deceleration, holds the shift direction if the envelope level increases, switches the shift direction if the envelope level decreases, and brings the envelope level close to the maximum value. The rotation of the capstan motor is controlled as described above.

Reference numeral 42 denotes a pilot signal extraction circuit.
A pilot signal included in a reproduced signal is separated from other signals by using a low-pass filter alone, a combination of a low-pass filter and a high-pass filter, or a band-pass filter. 43 is a pilot signal discriminating circuit for discriminating which of the four frequencies the separated pilot signal is. Details of the determination circuit will be described later.

The control of the pilot signal using the above configuration will be described. In the case of continuous recording, first, a recorded portion is reproduced for a predetermined period, tracking control is performed, and recording is performed in a state where tracking has been performed, thereby ensuring the continuity of the track pattern at the continuous portion. At the time when the tracking is achieved, the pilot signal discriminating process is started. For example, if it is determined that the frequency of the track currently being reproduced is f1, the rotation of the pilot signal generator is reset based on this, and the rotation is set so that the rotation starts at f2 from the next field. After a predetermined tracking period is over, the mode shifts to the recording mode. By the above operation, the continuity of the rotation of the pilot signal at the joint can be maintained.

FIG. 3 shows an embodiment of the pilot signal discriminating circuit.
Shown in This embodiment is an example in which a portion surrounded by a dotted line in the drawing is constituted by a microcomputer, and the other portions are constituted by analog circuits. 61 is a low-pass filter (hereinafter, LPF)
1) and 62 are high-pass filters (hereinafter, HPF1). 63 is an automatic gain control amplifier (hereinafter, AGC amplifier)
By detecting the output of the AGC amplifier by the detection circuit 64 and controlling the gain of the AGC amplifier by the detected signal, A
The output of the GC amplifier is kept constant. 6
1 to 64 constitute the pilot signal extraction circuit 42 of FIG. 65 is a low-pass filter (hereinafter, LPF2), 66
Is a peak detection circuit, and 67 is a low-pass filter (hereinafter, L
PF3). 71 is an A / D converter, 72 is a memory for temporary storage, and 73 is a comparator. Numeral 74 denotes a timing controller which receives a DPG signal, a DFG signal generated in synchronization with the rotation of the cylinder, and a system clock (also used as a source signal for generating a pilot signal in this case) as input, and adjusts the rotation phase of the cylinder. Various timing signals are generated synchronously. The timing controller 74 also controls the sampling timing of the A / D converter 71, the writing and reading timing of the memory 72, and the operation timing of the comparator 73. Reference numeral 75 denotes a frequency divider having a variable frequency division ratio, and reference numeral 76 denotes a circuit for controlling the frequency division ratio. The frequency division ratio is determined by SW30 from the timing controller 74 and S30.
A signal obtained by dividing the signal W30 by 2 (hereinafter referred to as SW15) is controlled by a 2-bit signal of SW15 'that is subjected to a polarity control process, and four division ratios are set by combinations of 1 and 0. Reference numeral 77 denotes a polarity control circuit which controls the inversion and non-inversion of the SW 15 from the timing control circuit 74 by the output of the comparator 73. Reference numeral 78 denotes a low-pass filter (hereinafter, LPF 4) for suppressing a harmonic component of a rectangular wave signal which is a divided output and obtaining a sine wave output.

FIGS. 3, 4 and 5 show the operation of this embodiment.
This will be described with reference to FIG. FIG. 4 schematically shows waveforms at various parts in FIG. 3 for explaining the operation of the present embodiment. FIG. 5 shows frequency characteristics of various filters. FIG. 4A shows the SW 30 which determines the scanning period of each of the heads 2 and 3. The SW 30 is synchronized with the rotation phase of the rotating cylinder 1 based on the DFG signal and DPG signal from the rotating cylinder 1 and the system clock of the microcomputer, and is generated at a timing when the heads 2 and 3 have an appropriate phase during the period of contact with the magnetic tape. (B) is SW15. The frequency of the pilot signal generated by four combinations of 1 and 0 of the 2-bit signal of SW30 and SW15 is controlled. Here, the combination is defined as follows. (SW30, SW15) is (0, 0) and f1,
(1, 0) is f2, (0, 1) is f3, (1, 1) is f
4 is assumed.

(C) is an output of the reproduction amplifier 16, which contains a video signal, an audio signal, and a pilot signal composed of a luminance signal and a chrominance signal. The audio signal and the video signal are suppressed by setting the cutoff frequency of the LPF 1 to be slightly higher (for example, 200 kHz) than the highest frequency f3 among the pilot signals as shown in FIG. As shown in FIG. 5, the cutoff frequency of the HPF1 is provided on the lower frequency side (for example, 50 kHz) of f1 having the lowest frequency among the pilot signals. This suppresses low-frequency noise such as the horizontal synchronization signal (about 16 kHz) and its harmonics, or mechanical noise. (D) shows the output of HPF1. Since the amplitude at this time is a small amplitude signal of about several tens mV, it is amplified to about several V by the AGC amplifier. If the variation in the amplitude of the reproduced pilot signal is sufficiently small, it is not always necessary to use an AGC amplifier, and an amplifier having a fixed gain may be used.
The configuration uses a C amplifier. After being amplified by the AGC amplifier (waveform (e)), the LPF 2 is passed, but the cut-off frequency of the LPF 2 is set to a frequency lower than f1 (for example, 100 kHz) as shown in FIG. Area. It depends on the type of filter, but about 6 × ndB with n-order low-pass filter
/ Octave slope. Therefore, since the amount of attenuation differs depending on the frequency of each pilot signal, the LPF2 output becomes (f)
As shown in the figure, a step occurs, f1 is the largest, f2, f
4, then f3. The signal shown in (g) is obtained by peak detection of this. However, at this point, since noise is present, smoothing is further performed by the LPF 3 to obtain a final detection signal (h). The above is the process up to generation of the detection signal from the reproduction signal.

Next, the rotation discrimination of the pilot signal using the detection signal and the rotation control of the generated pilot signal will be described with reference to FIG. The azimuth angle of the reproduction track and the azimuth angle of the reproduction head coincide with each other by reproducing the recorded portion and performing tracking control before recording. Therefore, the track reproduced by the −azimuth head is a track on which a pilot signal of f1 or f3 is recorded, and the track reproduced by the + azimuth head is a track on which a pilot signal of f2 or f4 is recorded. First, assuming that the phase of SW15 is the phase shown in (b), the frequency of the pilot signal of the track to be scanned becomes as shown in the figure. If the pilot detection signal at this time has the waveform shown in (c), it is the largest in the track of f1 and the smallest in the track of f3, so that the rotations match, and the phase of SW15 remains unchanged (waveform (e)). When the pilot detection signal has the waveform shown in (d), the track assumed to be f1 is actually the track of f3, and the rotation is shifted by two fields. Therefore, the phase of SW15 is inverted, so that the inverted signal is input to the frequency division value setting circuit as shown in (e). Thereby, rotation can be continued.

For the determination of f1 and f3, the pilot detection signal is sampled by the A / D converter 71 at the timing (SP1) indicated by x in FIG. 6 during the period assumed to be f1, and this value is stored in the memory 72. Next, during the period assumed as f3, the A / D conversion is similarly performed at the timing (SP2) also indicated by x,
This value is compared with the value stored in the memory 72. (SP1
If (data of SP2)-(data of SP2)> 0, 0 is output as a comparison result, and if (data of SP1)-(data of SP2) <0, 1 is output. If the exclusive OR (EOR) of SW15 and the comparison result output is obtained in the polarity control processing 77, the polarity of SW15 is kept as it is when the detection result is 0, and the inverted signal is outputted when the detection result is 1. The signal to which this processing is applied is referred to as SW15 ', and the frequency division value setting processing 76
The frequency division value is set by 30 and SW15 '.

The sampling point is set to one point in each of the tracks f1 and f3. However, if a plurality of points are sampled and integrated, the S / N can be improved and the detection accuracy can be improved. Further, according to the method of the present embodiment, since f1 and f3 having the largest frequency difference among the pilot signals are compared, the detection signal level difference can be increased,
Moreover, since the signal levels reproduced by the same head are compared, there is an advantage that the reproduction level is not affected by the performance variation among a plurality of heads.

In the above description, the level of the pilot signal included in the reproduced signal has not been described. However, since the reproduced output voltage is proportional to the frequency due to the magnetic characteristics at the time of reproduction, the signal is effectively passed through a high-pass filter of 6 dB / octave. Is equivalent to Therefore, the low-pass characteristics of the LPF 2 for pilot detection are canceled by the first order. Therefore L
The order of PF2 needs to be at least second order.
If the response characteristics of the AGC amplifier are sufficiently fast and the level difference due to the above magnetic characteristics can be absorbed, the level difference of the detection signal can be increased, so that the S / N can be improved and the detection accuracy can be improved.

Next, another embodiment of the pilot signal discrimination will be described. When a low-pass filter is used for pilot detection as described above, the effect of the first order is canceled out by the magnetic characteristics. Therefore, in this embodiment, a high-pass filter is provided instead of the LPF 2. The configuration diagram is shown in FIG. Reference numeral 68 denotes the high-pass filter (hereinafter, HPF2), and the other components are the same as those in the previous embodiment. As shown in FIG. 8, the frequency characteristic of HPF2 is close to the frequency f3 (for example, 2).
00 kHz). The operation of this embodiment is basically the same as the previous embodiment. However, since the magnitude of the pilot signal is reversed as shown in FIG. 9, the conditions for determination are also reversed. According to this embodiment, since the high-pass filter is not affected by the magnetic characteristics, or the level difference between f1 and f3 can be increased by the effect, the order of the filter can be reduced and the number of parts can be advantageously reduced. Become.

Next, another embodiment of the present invention is shown in FIG.
In the first embodiment, the generation method of the pilot signal is constituted by the frequency dividing circuit. However, the present invention is not necessarily limited to this. In the present embodiment, the feedback type pilot signal generation means by the voltage control oscillator (VCO) and the PLL control is used. Make up. 81 is a VCO, and 82 is a frequency dividing circuit which divides the output of the VCO to a frequency that can be processed by a microcomputer. A sampling circuit 83 detects the timing of the rising or falling edge of the divided signal. Reference numeral 84 denotes a phase comparator for obtaining a difference between the edge timing and the reference phase timing, that is, a phase error. The reference phase timing is generated by sequentially adding the target phase periods, and the target phase period is switched for each field by SW30 and SW15 '. The phase error is amplified to an appropriate level by an amplifier 86, and the pulse width modulator (P
WM), and the output is smoothed by a low-pass filter 88 and fed back to the VCO to form a PLL. According to the configuration of the present embodiment, a frequency divider having a variable frequency division ratio is not required, so that the degree of freedom in selecting a microcomputer is increased and the cost is reduced as a result.

An embodiment in which the present embodiment is applied and the response at the time of switching the frequency of the oscillator is made faster will be described with reference to FIG. If the processing speed of the microcomputer is sufficiently fast and the sampling frequency can be increased, the response at the time of switching can be made faster. However, when the sampling frequency is low, the response deteriorates accordingly, and it takes time until the frequency is stabilized after switching, which is a problem. Therefore, in this embodiment, the control voltage of the VCO is stored in a learning manner for each field, and the response after switching is speeded up. 10 in FIG.
Reference numerals 3 and 108 denote switches for switching between a steady state and initialization processing for speeding up. First, the operation in the steady state will be described. 101 is a memory for temporarily storing the target phase,
The target cycle data is added to the target phase data 101 by the adder 102.
And sequentially updated. The phase error signal generated by the phase comparison passes through a gain process 106, is added with DC offset data for setting an operating point by an adder 107, and is output from a PWM 87. 104 is a memory for temporarily storing a phase error signal, 109 is a memory for temporarily storing output data,
Each has four memories and corresponds to f1 to f4.
Next, the initialization process will be described. First, immediately after the field switching, the output data of the previous time (four fields before) stored in the memory 109 is used as a control signal, so that P
The frequency at the start of the LL control is controlled near the target frequency. In addition, the phase target is reset at the time of field switching in order to speed up the phase acquisition. At this time, the target cycle is added to the input sampling data (current phase data), and the value obtained by subtracting the previous (four fields before) steady phase error is used as the target phase. The reproduced state can be reproduced, and the speed of phase pull-in can be increased. With the above processing, the pilot signal can be switched at high speed even with a microcomputer having a low processing speed.

Finally, a control sequence using the present invention will be described. As described above, the pilot signal is very small and is amplified by about 40 dB to generate a signal for discrimination. Therefore, although the recording pilot signal is easily affected by noise, if the recording pilot signal jumps into the reproduced pilot signal, the two cannot be distinguished from each other. Therefore, the recording pilot signal is stopped during the determination. One example is shown in FIG. Advance the tape to remove the tape slack after power-on and paused (standby)
to go into. Next, when recording is started, first, a recorded portion is reproduced and tracking control is performed. The second row shows the operating state of the oscillator, and the lower row shows the operating state of the pilot determination. In the timing chart of the figure, the operation mode is set to the high period and the stop mode is set to the low period. As shown in the figure, the problem of the erroneous detection can be avoided by using a sequence in which the oscillation is stopped during the determination. In the case of the PLL oscillator, a learning period is required to improve the response time. However, as shown in the figure, the PLL control is performed prior to recording and learning is performed. Can be migrated.

Finally, another embodiment of the present invention will be described with reference to FIG. In this embodiment, a configuration is adopted in which a low-pass filter (LPF1) for detecting a pilot signal and a low-pass filter for generating a pilot signal have the same frequency characteristic, and the filter is also used. Reference numeral 69 denotes a switch which selects a reproduced signal when a pilot signal is detected and selects a frequency divider output when a pilot signal is generated.
Although this is applied to the embodiment of FIG. 3, it goes without saying that a similar configuration can be adopted in other embodiments.

[0027]

According to the present invention, a VTR of a recording system on the premise of using a pilot signal for tracking is used.
Therefore, even when continuous recording is performed by performing tracking control that does not use a pilot signal, the continuity of rotation of the pilot signal can be maintained, and when reproduced on another VTR, the image and sound may be disturbed at the continuous part. Absent.
Further, since the detection of the frequency of the pilot signal is performed by the LPF or the HPF, it can be realized with a simple circuit configuration. Further, since the level difference between the pilot signals f1 and f3 having the largest frequency difference in the same channel is detected, high-precision detection that is hardly affected by the level difference between channels and other noises is possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a schematic diagram of a track pattern for explaining tracking control.

FIG. 3 is a configuration diagram of an embodiment of a pilot signal detection unit using an LPF.

FIG. 4 is a waveform diagram for explaining an operation of detecting a pilot signal.

FIG. 5 is a frequency characteristic diagram of various filters.

FIG. 6 is an operation principle diagram of pilot signal detection.

FIG. 7 is a configuration diagram of an embodiment of a pilot signal detection unit using an HPF.

FIG. 8 is a frequency characteristic diagram of various filters.

FIG. 9 is an operation principle diagram of pilot signal detection using the HPF.

FIG. 10 is a configuration diagram of an embodiment in which pilot signal generation means is configured by a PLL method.

FIG. 11 is a configuration diagram of an embodiment relating to learning control of a PLL system.

FIG. 12 is a control sequence diagram.

FIG. 13 is a configuration diagram of an embodiment having a configuration also serving as an LPF.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder, 2, 3 ... Magnetic head, 4 ... Capstan motor, 21 ... Cylinder motor rotation control circuit, 32 ... Capstan motor rotation speed control circuit, 34 ... Envelope detection circuit, 35 ... Tracking control circuit, 41 ... Pilot Signal generation circuit, 42: pilot signal extraction circuit, 43: pilot signal discrimination circuit, 61, 65, 67, 78: low-pass filter, 62, 68: high-pass filter, 66: peak detection circuit, 73: comparator, 74: timing Controller, 77: polarity control processing, 75: frequency divider.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akifumi Mibe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi Media Media Research Laboratory (72) Inventor Yoshio Narita 1410 Inada, Katsuta-shi, Ibaraki Pref. Hitachi, Ltd. Personal Media Equipment Division (72) Inventor Teruo Hoshi 1410 Inada, Katsuta City, Ibaraki Prefecture Hitachi, Ltd. Personal Media Equipment Division (56) References JP-A-59-175053 (JP, A) JP-A-53 -90910 (JP, A) Japanese Utility Model 4-12111 (JP, U) Japanese Patent Publication 5-56585 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 15/467 G11B 5/588

Claims (3)

(57) [Claims] 1. A helical scan type magnetic recording / reproducing apparatus for cyclically recording pilot signals of a plurality of tracking frequencies on a recording medium by superimposing the pilot signals of a plurality of frequencies on a video signal in a cyclic manner. Pilot signal generating means, recording means for recording the pilot signal generated by the pilot signal generating means, reproducing means for reproducing the pilot signal from the recording medium, and a reproduced pilot connected to the reproducing means. Filter means having a second-order or higher-order low-pass filter characteristic having a different gain according to the frequency of the signal; detecting means for detecting the frequency of the pilot signal from the output of the filter means; The detecting means so that the circulation order of the pilot signal is continuous in a portion where the splicing recording is performed. Magnetic recording and reproducing apparatus characterized by comprising a control means for controlling the pilot signal generating means in accordance with the frequency of more the reproduced pilot signals. 2. The method according to claim 1, wherein the detecting means detects by comparing output values of the filter means in a period of a highest frequency and a period of a lowest frequency among the pilot signals of the plurality of frequencies. The magnetic recording / reproducing apparatus according to claim 1. 3. A recording method for recording a new video signal continuously on a recorded portion of a recording medium in which pilot signals of a plurality of frequencies are recorded in a predetermined circulation order so as to be superimposed on the video signal. Reproducing the pilot signal recorded on the recording medium, inputting the pilot signal to a filter having a second-order or higher-order low-pass filter characteristic having a different gain for each frequency of the pilot signal, and outputting the pilot signal by an output of the filter. And generating a recording pilot signal so that the circulating order on the recording medium is continuous according to the output of the detection. The generated recording pilot signal is superimposed on a video signal and recorded on the recording medium. Recording method characterized by performing.