JPS63119056A - Atf controller - Google Patents

Abstract

PURPOSE:To execute the locking with a prescribed track at the time of a variable speed reproduction, to facilitate the detection of an effective main signal to a signal processing and to stabilize a tracking by executing the tracking control of the combination of a head and an area with the combination different from the combination used at the time of the usual reproduction when the area is reproduced in which the signal for tracking control is recorded. CONSTITUTION:A head changing-over signal SW-H, ATF1 and ATF2 area identifying signals generated by an ATF area generating circuit 722, double speed and threefold speed reproduction discriminating signals X2 and X3, a normal reproduction-folding speed reproduction discriminating signal X/N, etc., are inputted to an SPL2 generating circuit 719, and at the time of folding speed reproduction, an SPL2 signal is controlled. Namely, at the time of the even number times speed reproduction, for example, at the time of the conditions of SW-H = 'H' and (ATF1 area + ATF2 area) = H, the output of the SPL2 signal is stopped, a tracking error voltage signal is not outputted from an output terminal 723, and at the time of the odd number times speed reproduction (X3 = 'H'), the output of the output terminal 723 is stopped by the conditions of ATF1 = 'H'. Thus, the tracking at the time of the folding speed can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ATF (automatic tracking and following) control method for a rotary head type outlet air regeneration device, and relates to an ATF control device suitable for use during variable speed regeneration. .

[Conventional technology]

Conventionally, in rotary head type magnetic playback devices such as VTRs, reference No. 16 is recorded on a control track provided at the end of the magnetic tape, and during playback, the running phase of the tape or the rotational phase of the rotary head is controlled based on this control signal. A method of tracking is generally used. However, this method requires a fixed head for detecting the control signal, and also maintains a constant relative positional relationship between the fixed head and the rotating head. It required I1 aircraft. Therefore, recently, for example, R-D
As seen in playback devices such as ATs (rotating head digital audio tape recorders), one track contains pilot signals in multiple areas (a few tracking control signals are divided and arranged, and By completing multiple blocks, ATF (Auto
Tracking Finding) method is used.

Related devices of this type include, for example, Japanese Patent Application Laid-open No. 6
No. 0-214415 and the like.

[Problem that the invention seeks to solve]

The above conventional technology is an effective tracking method for normal playback, but if the same ATF tracking control as for normal playback is applied during variable speed playback such as double speed or triple speed, it may lock in a state where tracking is not achieved or the main There was a problem that signal detection deteriorated and operation became unstable.

An object of the present invention is to lock at a predetermined track during variable speed playback to facilitate detection of a main signal effective for signal processing and to stabilize tracking.

[Means for solving problems]

The above purpose is to perform the tracking operation using the ATF signal by 2
During double speed playback, it is controlled by the ATF m number on the head input side and output side detected by one channel head, and during triple speed playback, it is controlled by the Aπ signal only on the head input side or only on the head output side detected by both channel heads. This is achieved by

[Effect]

Selects the ATF signals used for tracking control during variable speed playback, and uses only the ATF m numbers on the head input side and output side, which are detected by one channel head at double speed.
In addition, in a tracking control method that uses only the ATF No. 9 on the head input side detected by both channel heads at 3x speed, or the ATF signal on the head output side, control signals with contradictory correction directions for tracking are sent to one channel. Since the output is suppressed from being output alternately every time, and because it operates so as to only lock in the optimum tracking state, there is no possibility of tracking malfunction.

〔Example〕

An embodiment of the present invention will be explained below with reference to FIG. 1. FIG. 1 is a block diagram of a reproducing circuit used in, for example, an R1-DAT (rotating head type digital audio tape recorder). In the figure, 1 is a rotating cylinder, 2 is a magnetic head that is installed with an azimuth angle of 10 (hereinafter referred to as the human head), and 3 is a magnetic head that is installed with an azimuth angle of - (hereinafter referred to as this). (abbreviated as B head), 4 is a magnetic tape, 5 is a capstan, 6 is a capstan motor,
7 is a tracking ATF circuit, 8 is a cylinder motor,
9 is a cylinder servo circuit, 10 is a reproduction amplifier, 11 is a waveform equalization circuit, 12 is a data strobe circuit, 13 is a control circuit that controls digital partial processing and the operation of each circuit, 14! ! 15 is a memory circuit, for example, a key, 16 is an error detection and correction circuit, 17 is a D/A conversion circuit, 1 is an input circuit such as a microcomputer or keyboard, and 19 is a signal for identifying and controlling double speed playback. line, 2
G and 21 are L channel and R channel analog signal output terminals. First, a signal recorded on a magnetic tape 4 in a predetermined format to be described later is read by both fields A and B, passed through a reproduction amplifier 10, and then equalized by a waveform equalization circuit 11 into a signal with less code amount interference, and a data strobe circuit. In step 12, data ``O'' and ``1'' are discriminated and waveform shaped, and the result is input to the digital signal processing circuit 13 together with the reproduced clock. Here, PCM data is synchronized and demodulated, interleague is canceled, and the data is transferred to RAM.
Have 15 memorize one part. Furthermore, the data stored in the RAM is read out again, error detection and correction circuit 16 detects error data from the reproduced data, correctable data is corrected, and D/A conversion circuit 17 converts it into an analog signal. Output terminal 20 for 2-channel audio signal
．． Output from 21.

The cylinder servo circuit 9 controls the cylinder 8 to keep the rotational speed of the cylinder 1 constant. The ATF circuit 7 also inputs the reproduction envelope signal which is the output of the data strobe circuit 12, and uses a predetermined ATF signal to drive the capstan motor 6 to control the running of the magnetic tape 40 by the capstan 5 and perform tracking. A feature of this example is that the ATF circuit 7 has an operation function compatible with double-speed playback. In other words, the input circuit 18 of a microcomputer or the like inputs its identification signal 19 during double-speed playback, and for example, when double-speed playback is performed, a human head or B
Tracking control is performed only by ATF signals on the head input side and output side detected by either one of the heads, and, for example, when playing at 3x speed, A.

8 AT on the head entry or exit side detected by both heads
It operates to perform tracking control by validating only Fq. The digital signal processing circuit 13 outputs an analog signal through normal signal processing using only the PCMfr signal detected by one head (for example, a human head) during double speed reproduction based on the double speed reproduction identification signal 19.

Next, the tracking control method during double-speed playback according to the present invention and the operating principle that makes the above-described digital signal processing circuit operation effective will be explained in detail.

Before that, a brief explanation of the VcR and -Kai T signal mats will be given in FIGS. 2 and 3. Figure 2 shows the tape 7t-mat of Rr-DAT, in which vt is the tape running direction;
- is the head scanning direction, 41.42 is the top edge of the magnetic tape,
Indicates the bottom edge. a y d are track signals recorded alternately by both heads A and 8, and therefore adjacent tracks are recorded at different azimuth angles. Here, 45 and 47 are digital signal areas divided for subcodes, and 44 and 46 are area-divided areas for tracking during playback.

The ATF No. 1 area is 8UB1, ATFl, and the head exit side is abbreviated as 5UB2゜ATF2), 45 is the PCM signal area which is the main signal, and the signal of PCM area 45 is completed in 2 tracks (for example, c, d rack). Interleague processing (distribution of data) has been applied. The format of the area-divided ATE' signal is shown in Figure 3. In the figure, the same reference numerals as in the WJ2 figure indicate the same contents.

In addition, the oblique part represents the pilot signal area, f, , f represent the synchronization signal, and (A) and (B represent the heads used during recording. This area-divided ATF signal pattern is also effective against track bending. The pattern is completed with four tracks as shown in b to d of the same figure so that tracking can be achieved.

Now let's think about double-speed playback. FIG. 4 is a diagram showing a head trajectory when normal A'rF tracking is applied during double speed reproduction. In the figure, the same reference numerals as in FIG. 3 represent the same contents. Further, Ar1 is the head trajectory scanned by the human head at double speed, and BT2 is the head trajectory scanned by the B head, so that the trajectory of one head spans two tracks. Va 1 + N'a2 is human head is ATF
1. Represents the direction and magnitude in which the track position is relatively corrected as a result of detecting ATF 2 and performing tracking control.Similarly, Vbl and Vbl are
Indicates the direction and magnitude of tracking correction. Here VB
l+ va21 Vbl, direction of Vbl is ■ area 4
4.46 and Ar1. scanned by A and B heads. The area where the BT2 track locus overlaps S11+8a2+5l)t.

These are the directions in which Sbz is maximum, and the larger the area of the correction chamber, the smaller the correction chamber becomes. If normal ATF control is applied during double-speed playback in this way, Va2 and Vbt will balance out at any head position, and val and ■b2 will balance out and fall into an equilibrium state, making stable tracking impossible. Therefore, the main PCM signal is difficult to detect.

In addition, when outputting audio during double-speed playback, the signal processing circuit normally cancels all PCM data detected by one head, interpolates all lost data, and outputs the interpolated data. As mentioned above, this means that P-data has two adjacent
Interleaving is performed so that it is completed between tracks, and when one head trajectory spans two tracks, such as during double-speed playback, the PCM data that can be detected by one head due to the azimuth effect will be in the same azimuth as the head. This is because the Pl data of a different track is detected by another head, and the interleaving is deinterleaved based on this data as data of an adjacent track. .

Therefore, a tracking method in which only one track of PCM data is stably detected during double-speed playback becomes more effective. Therefore, according to the present invention, when playing at double speed,
For example, ATF 1, AT detected only by A head
Consider the case where tracking control is performed using F2. At this time, the tracking correction is performed as shown in FIG.
It will be held only in 12, and both val and va
Tracking correction is performed in the direction of the arrow indicated by □. FIG. 5 shows what the A head detects during double speed playback according to the present invention.

FIG. 3 is a diagram showing a track position that is stably locked as a result of tracking control performed only by ATFI and ATF2. In the figure, the same symbols as in FIG. 4 represent the same contents. Here, when 5a1=Sa2, Val and va
2 have the same size and the directions are opposite to each other, creating an equilibrium state. If Val and Va2 deviate from this position, an imbalance will occur between Val and Va2, and tracking correction will only be applied until this state is achieved, resulting in a stable state. Realize tracking. At this time, due to the azimuth effect, the reproduced PCM data is an area Pa where the A head trajectory AT2 with +azimuth overlaps with the d track recorded with +azimuth.
Similarly, Pbc and Pbd are detected by one azimuth, but as mentioned above, the only data required by the signal processing circuit during double-speed playback is Pa detected by the A head, and when tracking according to the present invention is performed, it is not necessary. The area of the main signal Pa can be increased, that is, the PCM
Stable tracking can be achieved at a position that makes it easier to detect data.

Next, an embodiment of the present invention will be described using triple speed playback as an example. FIG. 6 is a diagram showing the head trajectory, tracking correction amount, and direction when triple-speed playback is performed using conventional ATF racking. In the figure, the same reference numerals as in FIG. 4 represent the same contents. During triple speed playback, for example, as shown in Figure 6, the trajectory of one head spans three tracks K, and at this time, at any head position, 8a1 = 5a2 = Sbt
= Sbz, so no matter what the tracking state is, the correction amount and direction vat + va21
vb1*Vbz is in an equilibrium state, and stable tracking cannot be achieved.

Therefore, for example, according to the present invention, when playing back at 5x speed, A, B
FIG. 7 shows the only tracking position that is stably locked when tracking is performed using only the ATFl detected by the head. In the figure, the same symbols as in FIG. 4 represent the same contents. Here, the tracking position where the area of 8a1 and Sb1 is maximum is the only one in the state shown in Fig. 7, and if even one deviates from this, Val and Vbl will occur in the same direction and will be corrected until they return to the state shown in this figure. This means that
Tracking can be stabilized. At this time, the PCM data Pa required by the signal processing circuit also has a smaller area compared to double speed playback, making it difficult to detect.
This detection rate can be maintained and data can be reproduced stably.

The embodiments and operating principles of the present invention have been described above using double speed playback and triple speed playback as examples, but the same method can be applied to other double speed playbacks, that is, when 2n times speed playback (n = t
2.3...), tracking is performed using the ATFl and A'ff2 signals detected only by either the A or B head, and during 2n+1x speed playback, A,
Detected in both fields. ATF1 signal or ATF2
A similar effect can be achieved by performing tracking using only signals.

Next, ATF f! that realizes the present invention. tlJ? An example of the fI device is I! This will be explained using FIG. 8, FIG. 9, and FIG. 3 shown above. FIG. 8 is a block diagram of the A'[F control circuit according to the present invention, and FIG. 9 is a timing diagram explaining the basic operation of ATF control.

In FIG. 8, 701 is an input terminal for a signal reproduced and amplified by a head (not shown), and a low-pass filter (LPF) 702 receives the signal input from this terminal.
As a result, only low-frequency pilot signal components are selected, and the envelope detector 703 extracts their envelopes. This envelope signal passes through a buffer 704 and a switch 705, and a voltage value corresponding to its peak value is held by a holding capacitor 709. On the other hand, the opening and closing of the switch 705 is controlled by the timing of a signal 5PL1, which will be explained later. Charge is sent to the hold capacitor 709 while the switch 705 is closed (sample operation), and when the switch 705 is opened, the current value is Voltage is stored in the capacitor (hold state).

Switch 705 opens as described above and capacitor 710
When the buffer 704 enters the hold state, the envelope signal output from the buffer 704 is input to the positive input terminal of the differential amplifier 706. On the other hand, the capacitor 709 is connected to the differential amplifier 7.
It is connected to the negative input terminal of 06.

Therefore, the output of the differential amplifier a 706 becomes a voltage corresponding to the difference between the capacitor voltage value held at the timing of the signal 5PLI and the output of the buffer 704, that is, the envelope signal. This output voltage is stored in the other hold capacitor 710 via switch 707.

The opening and closing of the switch 707 is controlled by the timing of a signal 5PL2, which will be explained later, and is in a hold state from the time the switch 707 is opened.

As a result, the voltage held in the capacitor 710 becomes a voltage corresponding to the difference between the output (ie, envelope voltage) of the buffer 704 at the timing of the signals 8PL f and 5PL2. This hold voltage is the buffer 708
via ATF) as the racking error signal at terminal 72.
3 is output.

As described above, the signals 8PL1 and 5PL2 play a very important role in detecting the envelope voltage of the pilot signal. Next, sample pulse signal 5PL1
The generation mechanism of is explained.

In FIG. 8, 711 is a band pass filter (BPF) that extracts a synchronization signal that provides timing for generating signals 8PL1 and 8PL2. After passing through f3PF 711, the synchronization signal having a constant frequency is waveform-shaped by a comparator 712. and converted to a square wave. 724
is a voltage source that provides the basic voltage of the comparator 712. The output of the comparator 712 is determined by the synchronization signal pattern detection circuit 713 to determine whether or not it is a synchronization signal, and each time a synchronization signal pattern (one wave of a constant frequency signal) is detected, a pulse signal is sent to the next stage synchronization signal counter. Send to 714. Here, as shown in the ATF signal recording pattern of FIG. 3, two types of frequency tfl numbers, f, , and f, are used as the synchronization signal. ! , and f correspond to each of the two heads attached to the rotating cylinder.

In the figure, f2 is for the human head, and f is for the B head.

It is closed. Two ATF areas (ATF'1 and ATF2) are provided at the tape input side and tape output side. Furthermore, the areas occupied by these synchronization signals have different lengths of 1t.
There are 281 types, the area of ``ASt'' and the area of ``aSt''. Whether the synchronization signal is f or f is determined by the head switching signal generation circuit 72 in FIG.
1 by inputting the tack signal DTP to the terminal 720 as well, and the head switching signal is used for identification.

Next, the aforementioned counter 714 sends a signal to an ATF area counter 715 (described later) indicating that a synchronization signal pattern has been detected. Here, the signal based on the first synchronization signal detected by the detection circuit 713 is
8, and the circuit 718 outputs a signal 5PL1.

As shown in FIG. 9, which will be described later, this generation timing is located almost at the beginning of the synchronizing signal area (in the signal area).

On the other hand, the count result of the synchronization signal counter 714 is sent to the comparator 716 and the comparator 717, and compared with a predetermined threshold value.
16 to the SPL 1 formation circuit 718, and the comparator 7 to 7 to the SPL 2 formation circuit 719.

The ninth factor shows the timing factor of 8PL1.8PL2 signal generation. FIG. 9 is a time chart showing the operation of each part when the head runs on a track, and shows the case where a synchronization signal is detected corresponding to a recording pattern. First, when the head enters the area where the synchronization signal is recorded, the synchronization signal is detected, and if the detection of the synchronization signal (it or 7.) is recognized, as described above, 5PL1! The signal immediately changes from °H゛ to "C".

When the signal 5PL1 is "C", the detected voltage is held in the capacitor 709 in FIG. (Count value N in Figure 9).

Here, the features of this *m example are the head switching signal 5W-H shown in FIG. 8, the ATF1 generated by the ATF area raw bottom circuit 722, the ATF2 area identification signal, and the double speed.

3x speed playback occupation signal X2. X3, normal playback/double speed playback zone specific signal X/N, etc. are input to the 8PL2 generation circuit 719 to control the K8PL2 signal during double speed playback. In other words, during even-numbered double speed playback (X2="H"), for example, when the conditions are 8W-H="H" and (ATF1 area + ATF2 area) -H, the output of the 8PL2 signal is stopped and the tracking error voltage signal is output from the output terminal 726. It is possible to realize the present invention by not outputting the output terminal 723 and by stopping the output of the output terminal 723 under the condition of ATFl = "H" during set speed playback (X3 = "H"). The conditions can be easily configured using simple logical operation circuits.

〔Effect of the invention〕

According to the present invention, it is possible to create a unique state in which the tracking correction amount and direction are balanced during double-speed playback, so tracking during double-speed playback is stabilized, and the PCM jM detected by a single head, which is required by the signal processing circuit, is made stable. This has the effect of stably detecting signals.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the playback circuit of R-DAT according to the present invention, Figure 2 is a tape format diagram of R-DAT, Figure 3 is an ATF pattern diagram of R-DAT, and Figure 4 is a track during double speed playback. FIG. 5 is a tracking trajectory diagram during double speed playback according to the present invention, FIG. 6 is a track trajectory diagram during 5X playback, FIG. 7 is a tracking trajectory diagram during triple speed playback according to the present invention, and FIG. The figure shows ATF control g &
FIG. 9 is a block diagram showing one embodiment of the present invention, and is an operation timing diagram of the ATF control device. 705...Envelope detection circuit u, 721...Head switching signal generation circuit, 722...A
TFL, ATF2 area generation circuit, 718...5
PL1 raw bottom circuit, 719...5PL2 generation circuit, 709.71Q...hold capacitor, 705,7
07...Switch, 5W-H...Head switching signal, X2...Even multiple speed playback identification signal, X3...Odd number multiple speed playback identification signal, X/N...Normal playback-double speed playback job specific signal , 723
...Tracking error voltage output terminal. , 20° 2nd mouth cb e la bueno ° (lower Achi) 4th corner S mouth 4 dozu cba Meotomi J e d c l) (2-42 Akira 7 Akakura 9 concave → -II →÷−2!−1

Claims (1)

[Claims] 1. A plurality of areas are provided on one track of a magnetic tape, and each area is provided with a pilot signal for forming a tracking error signal and a synchronization signal for providing the detection timing of the pilot signal. In a tracking control device such as a rotary head type magnetic reproducing device that performs ATF tracking control for controlling the rotational phase of the capstan by dividing recording and detecting the pilot signal and synchronization signal during reproduction, variable speed reproduction is possible. Sometimes, when a plurality of playback heads included in the playback device are used to play back an area in which tracking control signals provided in the plurality of playback heads are recorded, at least one combination of the head and the area is used. ATF that performs tracking control using a combination different from the combination used during normal playback.
Control device. 2. In claim 1, during double-speed playback, one or more of the tracking signal recording areas arranged on the head entry side detected by one channel head of the plurality of playback heads is detected by playing back. An ATF control device that performs tracking control using only a tracking error signal detected by reproducing and detecting one or more regions disposed on the head exit side that can be simultaneously detected by the head. 3. In claim 1, at the time of triple speed playback, one or more of the plurality of playback heads is detected by two or more heads including at least both channels, either on the input side or the output side. An ATF control device that performs tracking control using a tracking error signal detected by reproducing the tracking signal recording area.