JPH0432062A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain the stable and normal on-track state of a magnetic head by converting a reference voltage and the extent of tracking error to digital quantities and comparing them with each other. CONSTITUTION:A tracking error detecting means 41 which detects the extent of tracking error in accordance with a pilot signal on an adjacent track as the output of a head 21, a first AD converter 29 which converts the extent of tracking error to the digital quantity, and a second AD converter 30 which converts the reference voltage of ATF control to the digital quantity are provided. Tracking servo of the ATF system is applied by the output of an operation part 31 which compares the output of the first AD converter 29 and than of the second AD converter 30 with each other. Thus, the stable and normal on-track state of the magnetic head is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to video tape recorders (VTRs), digital audio tape recorders (DATs), etc., in which information on tracks formed diagonally on a magnetic tape is transferred to the information written on the tracks. The present invention relates to a magnetic recording and reproducing device that performs tracking using an ATF signal and reproduces data using a rotary head.

Background of the Invention In recent years, rotating head type magnetic recording and reproducing devices have become more popular as magnetic recording and reproducing devices become more densely recorded, such as image recording and audio PCM. A digital control method has been adopted to reduce costs and reduce costs.

The above-described conventional magnetic recording/reproducing device will be described below with reference to the drawings.

FIG. 4 shows a capstan control system using an ATF signal of a conventional magnetic recording/reproducing device.

In FIG. 4, 1 is a magnetic tape. Reference numeral 2 denotes a magnetic head mounted on a rotating cylinder, which, in conjunction with a hand amplifier 3, reproduces recorded information on the magnetic tape 1. Reference numeral 4 denotes a pilot signal detection circuit provided after the head amplifier 3, which detects the pilot signal from the reproduction head output of the head amplifier 3. Reference numeral 5 denotes a sync signal detection circuit provided at a subsequent stage of the head amplifier 3, similar to the pilot signal detection circuit 4, which detects the sync signal from the playback head output of the head amplifier 3. 6 is a timing circuit, and sync signal detection circuit 5
The sync signal detected by is input, the reproduction timing of the pilot signal of the adjacent track is detected, and a sample pulse is generated. Reference numeral 7 denotes a first sample and hold circuit to which the output of the pilot signal detection circuit 4 and the output of the timing generation circuit 6 are input, and this first sample and hold circuit 7 receives the pilot signal ratio power level of the pilot signal detection circuit 4. and hold the sample.

Reference numeral 8 denotes an arithmetic circuit, into which the output of the pilot signal detection circuit 4 and the output of the first sample-and-hold circuit 7 are input, and performs arithmetic operations. Reference numeral 9 denotes a second sample and hold circuit, into which the output of the arithmetic circuit 8 is input as a tracking error amount and sampled and held. 10 is an AD converter that converts the output of the second sample and hold circuit 9 into a digital quantity.

Reference numeral 11 denotes a subtraction circuit, and this subtraction circuit 11 subtracts the center value of AD conversion from the output data of the AD converter 1° as a reference for ATF control. A gain adjuster 12 receives the output of the subtraction circuit 11 and adjusts the gain of the ATF control system.

13 is a capstan for running the magnetic tape 1. 1
4 is an FG which generates a frequency signal proportional to the rotational speed of the capstan 13; 15 is a periodic voltage detection circuit, FGl
The period of the frequency signal which is the output of step 4 is measured with high precision.

16 is a capstan rotation control circuit, and period detection circuit 15
The detected rotation period data of the capstan 13 and a preset target period of the capstan are calculated, and torque command data is outputted so that the capstan 13 reaches a desired rotation speed.

1γ is an adder to which the output of the gain adjuster 12 and the output of the capstan control circuit 16 are input, and this adder 17 receives the ATF control data which is the output of the gain adjuster 12 and the output of the capstan control circuit 16. Adds torque command data. 18 is a DA converter provided after the adder 17, which converts the output data of the adder 17 into an analog quantity. Reference numeral 19 denotes a drive circuit provided after the DA converter 18, which drives the capstan 13 according to the output of the DA converter 18. 4o is a reference voltage block that generates a reference voltage, and this reference voltage is passed through the first sample and hold circuit 7. Second sample and hold circuit9. Arithmetic circuit 8. The operation reference voltage of the drive circuit 19 is 1, and the polarity reference voltage for acceleration/deceleration of the capstan 13 is used.

The operation of the magnetic recording/reproducing apparatus configured as above will be described below.

First, from the output signal of the magnetic head 2 amplified by the head amplifier 3, the pilot signal detection circuit 4 uses a film or the like to extract the ATF signal/turf diagram pilot signal f1 shown in FIG. The pilot signal output waveform is shown in FIG. 6(a). Similarly, the sync signal detection circuit 6
The sync signals f2 and f3 shown in the figure are extracted. The sync signal output waveform is shown in Figure 6). In response to the detection of this sync signal, the timing circuit 6 generates sample pulses SP as shown in FIGS.
1 and SF3 are generated. A voltage proportional to the amount of extension of the magnetic head 2 to the adjacent track where the pilot signal is recorded is applied to the sample pulse S by the first sample hold circuit 7.
Sample and hold is performed at the timing of P1. Next, the tension bm of the magnetic head 2 to the adjacent track to be traced is
The difference between the voltage proportional to the amount of water and the output of the first sample-hold circuit 7 is calculated by the arithmetic circuit 8, and the value is sampled and held by the second sample-hold circuit 9 at the timing of the sample pulse SP2, as shown in FIG. Obtain the output shown in e). The output of the second sample and hold circuit 9 is a voltage indicating the difference in the amount of tension of the magnetic head 2 to both adjacent tracks, that is, a tracking error.

In ATF control, this voltage is controlled to be equal to the reference voltage indicating the polarity of acceleration/deceleration of the capstan 13,
On-track control becomes possible. The amount of tracking error is converted into digital data by the AD converter 10.

The subtraction circuit 11 calculates the difference between the output data of the AD converter 1o and the center value (aoH) of the AD converter 1o, and inputs this difference to the gain adjuster 12. Here, the output of the gain adjuster 12 is inputted to the adder 17 as a value such that a desired ATF gain can be obtained.

On the other hand, the period detection circuit 15 detects the entire rotation period of the υ capstan 13 based on the frequency signal output from the Fe 12, and the capstan control circuit 16 detects the difference between the detected rotation period and the target rotation period of the capstan 13. Then, torque command data compared to this difference (periodic error) is output. Adder 1
7, this torque command data and the aforementioned gain adjuster 12
Adds the output data of . The DA converter 18 converts the output of the adder 17 into an analog quantity (voltage) and sends it to the drive circuit 1.
9, and the speed control and ATF control of the capstan 13 are performed by the output of the drive circuit 19.

By controlling the capstan 13, the on-track state of the magnetic head as shown in FIG. 7 is obtained.

Problems to be Solved by the Invention However, in the above configuration, an error occurs between the center value of the AD converter 1o and the reference voltage in the second sample-and-hold circuit 9 due to variations in the elements, as shown in FIG. ATF control is performed in a state where there is an offset due to an error, and a normal on-trunk state cannot be obtained.

In view of the above-mentioned problems, the present invention provides a highly accurate and stable ATF that can obtain a normal on-trunk state with a simple configuration.
An object of the present invention is to provide a magnetic recording and reproducing device that can accurately reproduce recorded information on a magnetic tape by applying control.

Means for Solving the Problems In order to solve the above problems, the magnetic recording/reproducing apparatus of the present invention tracks information recorded on the magnetic tape using ATF signals on tracks formed on the magnetic tape. A magnetic recording/reproducing device for reproducing information, which includes a capstan with a constant rotational speed, a head for reproducing information recorded on the magnetic tape, and a tracking error i based on a pilot signal of an adjacent track output from the head.
A tracking error detection means for detecting the tracking error, a first AD converter for converting the tracking error amount into a digital amount, and a second AD converter for converting a reference voltage, which is a reference for ATF control, into a digital amount. and a calculation unit that compares and calculates the output of the first AD converter and the output of the second AD converter, and applies tracking servo using an ATF method based on the output of the calculation unit. It is.

Function The present invention uses the first AD converter and the second AD converter to convert the reference voltage and the tracking error amount into digital quantities and performs a comparison operation, so the result of the comparison operation becomes a digital quantity and is accurate. ATF control can be performed, and a stable and normal on-trunk state of the magnetic node can be obtained.

Example Below, regarding a magnetic recording and reproducing device according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 is a block diagram showing a capstan control system of a magnetic recording/reproducing apparatus in an embodiment of the present invention. In FIG. 1, 20 is a magnetic tape.

A magnetic head 21 is in contact with the magnetic tape 20, and in conjunction with a head amplifier 22 reproduces recorded information on the magnetic tape 2o. Reference numeral 23 denotes a pilot signal detection circuit provided after the head amplifier 22, which detects the reproduced output of the head amplifier 22 and the pilot signal. Similarly to the pilot signal detection circuit 23, a sync signal detection circuit 24 is provided after the head amplifier 22, and detects the sync signal from the reproduction output of the head amplifier 22. A timing generation circuit 25 detects the reproduction timing of the pilot signal of the adjacent track from the sync signal detected by the sync signal detector 24, and generates a sample pulse. 26 is a first sample and hold circuit into which the output of the pilot signal detection circuit 23 and the output of the timing generation circuit 25 are input, and this first sample and hold circuit 2θ is input with the pilot signal output level of the pilot signal detector 23. and hold the sample. 2 is an arithmetic circuit, and this arithmetic circuit 27
The output of the pilot signal detection circuit 23 and the output of the first sample and hold circuit 26 are inputted to perform calculations. 2
8 is a second sample and hold circuit, and this second sample and hold circuit 28 samples and holds the output of the arithmetic circuit 27. The output of this second sample and hold circuit 28 becomes the amount of tracking error. Note that the tracking error detection means 41 includes a pilot signal detection circuit 23,
Sink signal detection circuit 24. Timing generation circuit 25. First sample and hold circuit 26. Arithmetic circuit 27 and second
The sample and hold circuit 28 is comprised of a sample and hold circuit 28.

29 is a first AD converter that converts the output of the second sample and hold circuit 28 into a digital quantity. 3o is the second A
A D converter converts the ATF control reference voltage into a digital quantity. 31 is a subtracter (operation unit) to which the outputs of the first AD converter 29 and the second AD converter 30 are input; Subtract the output. A gain adjuster 32 receives the output of the subtraction circuit 31 and adjusts the gain of the ATF control system. 33
is a capstan that runs the magnetic tape 2o. 34
is an FG which generates a frequency signal proportional to the rotation of the capstan 33. 35 is a cycle detection circuit that measures the cycle of the frequency signal output from the FG 34 with high precision.

36 is a capstan rotation control circuit, and period detection circuit 35
The detected rotation period of the capstan 33 is calculated with a preset target period of the capstan, and torque command data is outputted so that the capstan 33 reaches a desired rotation speed. 37 is an adder into which the output of the gain adjuster 32 and the output of the capstan 33 are input, and this adder 37 receives ATF control data which is the output of the gain adjuster 32 and torque command data which is the output of the capstan control circuit. Perform the addition of . 38 is a D provided after the adder 37.
The A converter converts the output of the adder 37 into an analog quantity. Reference numeral 39 denotes a drive circuit provided after the DA converter 38, which drives the capstan in accordance with the output of the DA converter 38. 5ol-1: A reference voltage block that generates a reference voltage for ATF control. This is the operating reference voltage for the arithmetic circuit 27 and the drive circuit 39, and serves as the polarity reference voltage for acceleration/deceleration of the cab stun 33.

The operation of the magnetic recording/reproducing apparatus configured as described above will be described below with reference to FIGS. 1 and 2.

Magnetic head 21 amplified by Masuheno amplifier 22
From the reproduced output signal, the pilot signal detection circuit 23 extracts the ATF signal-turf diagram pilot signal f1 shown in FIG. 5 using a filter or the like. The pilot signal output waveform is shown in FIG. 2 (+1). The sync signal detection circuit 24 similarly extracts sync signals f2 and f3 shown in FIG. The sync signal output waveform is shown in Fig. 2 Φ). In response to the detection of this sync signal, the timing circuit 25 generates sample pulses SP1 and SF3 shown in FIGS. 2(C) and 2(d) at the start of detection and after a certain period of time. A voltage proportional to the amount of extension of the magnetic head 21 to the adjacent track where the pilot signal is recorded is supplied to the first sample bold circuit 26.
The signal is sampled and held at the timing of the sample pulse sP1. Next, the difference between the voltage proportional to the amount of extension of the magnetic head to the adjacent track to be traced and the output of the first sample bold circuit 2θ is calculated by the arithmetic circuit 27, and this value is applied to the second sample hold circuit 28. The signal is sampled and held at the timing of the sample pulse SP2, and an output as shown in FIG. 2(e) is obtained. The output of the second sample and hold circuit 28 is a voltage indicating the difference in the amount of protrusion of the magnetic head 21 to both adjacent tracks, that is, a tracking error.

This amount of tracking error is converted into digital data by the first AD converter 29. Further, the second AD converter 30 is connected to the capstan 3 where the reference voltage block 60 is generated.
The reference voltage of acceleration/deceleration polarity No. 3 is converted into digital data and applied to the subtracter 31. The subtracter (calculation unit) 31 calculates the difference between the output data (digital amount) of the first AD converter 29 and the second AD converter 30 and outputs ATF control data. Therefore, accurate ATF control data can be obtained. From then on, A
The TF control data is output to an adder 37 via a gain adjuster 32 so that a desired ATF gain can be obtained.

On the other hand, the period detection circuit 35 detects the rotation period of the capstan 33 based on the frequency signal output from the FG 34, and the capstan control circuit 3e detects the difference between the detected rotation period and the target rotation period of the capstan 33, Torque command data compared to this difference (periodic error) is output. Adder 3
At the end, this torque command data and the aforementioned gain adjuster 32
Add the pressure data. Adder 3 with DA converter 38
The output of 7 is converted into an analog quantity (voltage) and the drive circuit 39
The capstan speed control and ATF control are performed by the output of the drive circuit 39. By controlling the capstan 33, the on-trunk state of the magnetic head as shown in FIG. 3 is obtained.

As described above, according to this embodiment, the first AD converter 29
The tracking error amount which is the output of the second sample and hold circuit 28 is converted into a digital value, and the second AD
The converter 3o converts the reference voltage that serves as the reference for ATF control into digital data, and the subtracter (calculation unit) 31 performs a comparison operation on the nine digital data, thereby eliminating fluctuations in the reference voltage due to element variations, etc. Accurate ATF control data without errors can be obtained. Also calculated A
The gain of the TF control data is adjusted by the gain adjuster 32, the output of the gain adjuster 32 is added to the torque command data of the capstan control circuit 36 by the adder 37, and the output of the adder 37 is added to the DA converter. 38 through the drive circuit 39
By applying this to , highly accurate and stable A T F fIi'lJ control can be performed with a simple circuit configuration.

Effects of the Invention As described above, the present invention includes a first AD converter that converts a tracking error amount into a digital amount, and a second AD converter that converts a reference voltage, which is a reference for ATF control, into a digital amount.
Since it is equipped with a converter, the reference voltage is a digital quantity and does not vary. Moreover, the results of calculating the outputs of the first AD converter and the second AD converter in the calculation section are outputted as accurate digital quantities, so this output can be used to perform highly accurate and stable ATF control of the magnetic recording/reproducing device. I can do it.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a capstan control system of a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram regarding tracking errors in a magnetic recording/reproducing device according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram of a capstan control system of a conventional magnetic recording and reproducing device. FIG. 5 is an ATF signal-turf diagram. FIG. 6 is a signal waveform diagram regarding a tracking error in a conventional magnetic recording/reproducing apparatus, and FIG. 7 is a plan view showing an on-track state of a magnetic head in a conventional magnetic recording/reproducing apparatus. 21... Magnetic head, 29... First AD converter, 3o... Second AD converter, 31
・・・・・・Subtractor (computation unit), 33... Song capstan, 41... Song tracking error ~ inspection means. Name of agent: Patent attorney Shigetaka Awano and one other person
2. Flute diagram/Trai Rit? yter1 :),': shi1

Claims (1)

[Claims] A magnetic recording and reproducing device that performs tracking using ATF signals on tracks formed on a magnetic tape and reproduces information recorded on the magnetic tape, the device comprising: a capstan with a constant rotation speed; a magnetic head for reproducing recorded information; a tracking error detection means for detecting a tracking error amount from a pilot signal of an adjacent track output from the magnetic head; and a first AD for converting the tracking error amount into a digital amount.
a converter, a second AD converter that converts a reference voltage that is a reference for ATF control into a digital quantity, and a calculation that compares the output of the first AD converter and the output of the second AD converter. What is claimed is: 1. A magnetic recording/reproducing device comprising: a magnetic recording/reproducing device, wherein a tracking servo is applied using an ATF method based on the output of the calculating portion.