JPS6222258A - Rotary head type tape recorder - Google Patents

Abstract

PURPOSE:To attain stable tracking control by controlling the gan of an amplifier circuit inversely proportional to the summing signal level of a reproduced pilot signal component of two adjacent tracks of a reproducing track so as to prevent fluctuation due to variation. CONSTITUTION:An adder 13 outputs an addition signal of a reproduction pilot control signal component of two adjacent tracks of the reproduction track included in an output signal of the circuit 2 amplifying a reproducing signal of a rotary head. Further, a circuit 23 forms a gain control signal inversely proportional to the output level of circuits 14, 15 sampling and holding the addition signal of the adder 13, gives the signal to the circuit 2. Whose amplifier gain is controlled variably. Thus, the fluctuation of a tracking control error signal outputted from an error signal output section 10 is prevented due to the variation in the tracking control pilot signal recorded on a tape so as to attain stable tracking control.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides an independent recording area for a tracking control pilot signal on each track of a tape, and during playback, a recording area for a pilot signal for tracking control is provided, and during playback, a pilot signal included in the playback signal of a rotating head is recorded. The present invention relates to a rotary head type tape recorder such as a rotary head type digital audio tape recorder that performs tracking control based on a level difference between reproduction pilot signal components of two adjacent tracks.

[Conventional technology]

Conventionally, this type of rotary head type tape recorder (hereinafter referred to as 11L) such as a rotary head type digital audio tape recorder
DAT) is currently R,-DAT Technical Review Group (referred to as DAT).
Standardization of recording and reproducing methods is being promoted by R-DAT ATF AD-HOCMEETING).

The technology review committee proposed that υ tapes be recorded and played back using a helical scan method using a rotating head, and tracking control during playback using an automatic tracking method using a pilot signal, that is, an ATF method. Proposed.

By the way, in order to perform ATF-based tracking control, each track on the tape is
1 New 1 Pilot signal 4 Synchronization signal AT distributed by Sony Corporation on August 21, 1984
F method (New pilot 45 sync ATF
method)” and Japanese Unexamined Patent Publication No. 112-1983
As described in Japanese Patent No. 406, it is necessary to form an information recording area and a tracking control pilot signal recording area in a time-division manner.

To explain the tape recording format described in the above document, as shown in FIG. 5, pilots (α) are provided at both ends of each track (A), CB) of the tape (T), and each track The area between the ATF areas (α) in (A) and (B) is set as a digital information recording area φ).

Note that track (A) indicates a track with a dead number or an even number, and track (B) indicates a track with an even number or an odd number. Further, the arrows and t indicate the running directions of the rotary head and the tape (T), respectively.

And the recording area (p) has a frequency f + (#130
KETz) pilot signal is recorded, and the recording area (S) has a frequency r2 (-522KHz) for each track.
), f3 (B4 KH2) are recorded with alternating synchronization signals, and in the recording area (e), an erasure signal with a frequency of f4 (=1.568 MHz) is recorded.

On the other hand, the gap width of the rotary head used for recording and reproduction is set slightly wider than that of each track (A) and (B), and during reproduction, the rotary head traces a trace track and a portion of each of the two adjacent tracks of the track. However, the reproduction output signal of the rotary head includes a reproduction signal component of the trace track and reproduction signal components of two adjacent tracks.

Then, the recording area (p
) are set so that they do not overlap between four consecutive tracks, and each track (A), (B
) is formed at a position where one or the other recording area (p) of two adjacent tracks is simultaneously traced when the area < S) is traced. Track recording area (S
), the recording area (1)) of one or the other of the two adjacent tracks is simultaneously traced, and the recording area (1) of the other or one of the two adjacent tracks is traced after a certain period of time from the tracing of the recording area (S) of the trace track. (pl is traced.

In the pod, the trace track pilot signal.

The frequency of the synchronization signal is the pilot signal of two adjacent tracks,
Since the frequency is different from that of the synchronization signal, by filtering the rotary head reproduced signal, reproduced pilot signal components of two adjacent tracks included in the rotary head reproduced signal are extracted.

By the way, a difference in level occurs between the extracted reproduced pilot signal components of two adjacent tracks because the tracking position of the rotary head deviates from the optimum position.

Therefore, during reproduction, the reproduced pilot signal components of two adjacent tracks included in the reproduced signal of the rotary head are respectively extracted, and a tracking control error signal proportional to the level difference between the two reproduced pilot signal components is formed. By controlling the running phase of the tape (T) so that 0 becomes 0, ATF type tracking control is performed and the tracking position of the rotary head is controlled to the optimum position.

[Problems to be solved by the invention] By the way, the level of the pilot signal for tracking control recorded on the tape ('I') is subject to variations in the recording/reproducing ability of the recording current one-turn head, the sensitivity of the tape (T), etc. Therefore, it is difficult to keep it constant.

Therefore, the level of the reproduced pilot signal component of two adjacent tracks included in the reproduced signal of the rotary head varies depending on the tape even at the same tracking position, and in this case, the level of the error signal for tracking control varies depending on the tape. On the other hand, there is a problem that stable tracking control cannot be performed.If the level of the tracking control error signal becomes extremely low, tracking control cannot be performed.

In addition, in the case of I(, -DAT, each track (A), (
Since B) is alternately recorded and reproduced, the level of the tracking control error signal differs depending on the reproducing rotary head based on variations in the recording/reproducing ability of the rotary head.

[Means for solving problems]

The present invention has been made with the above-mentioned points in mind, and includes a tape in which a recording area for a tracking control pilot signal is independently provided in each track, and a tape in which a gap width is set wider than each track, and Rotate head to play and trace.

an amplifier circuit that amplifies and outputs the reproduced signal of the head with automatic gain control; and an amplifier circuit that extracts reproduced pilot signal components of two tracks adjacent to the reproduced track included in the output signal of the amplifier circuit, and extracts reproduced pilot signal components of the two adjacent tracks. an error signal output unit that outputs an error signal for tracking control at a level of the difference between the components; an adder that outputs a sum signal of the reproduced pilot control #J signal components of the two adjacent tracks;
A sample and hold circuit that samples and holds the addition signal; and a gain control circuit for forming a gain control signal that variably controls the gain of the amplifier circuit in inverse proportion to the level of output No. 8 of the sample and hold circuit. This is a rotary head tape recorder featuring:

[Effect]

The sum of the reproduced pilot signal components of two adjacent tracks included in the reproduced signal of the rotary head is approximately constant regardless of the tracking position, taking into account crosstalk and franging effects.

Therefore, the level of the addition signal of the adder changes in proportion to the dispersion of the tracking control pilot signal recorded on the tape, and at this time, the gain of the amplifier circuit is variably controlled in inverse proportion to the addition signal, so the amplification The level of the reproduced signal output from the circuit to the error signal output section is controlled so that the level of the reproduced pilot signal component included in the reproduced signal does not change due to the above-mentioned fluctuation.

〔Example〕

Next, the present invention will be explained in detail with reference to FIGS. 1 to 4 showing one embodiment thereof.

Figure 1 shows two rotating heads, l:! A normal R, -DA of the two-head helical scan system that alternately reproduces each track of the tape (T) with the recording format shown in Figure 5.
In the example shown in the figure, (1) is a reproduction signal input terminal to which reproduction signals of both rotary heads are input;
2) is an amplifier circuit connected to the input terminal (II), which is formed by an automatic gain control amplifier whose amplification gain is variably controlled in inverse proportion to the level of a gain control signal, which will be described later.

(3) is a low-pass filter connected to the amplifier circuit (2), which extracts only the reproduced pilot signal component.

(4) is a detection rectifier circuit connected to the filter (3), (5) is the first sample and hold circuit connected to the rectification circuit (4), and (6) has one input terminal connected to the sample and hold circuit ( 5), the other input terminal of which is connected to the rectifier circuit (4). (7) is a second sample and hold circuit connected to the output terminal of the subtracter (6), (8) is a buffer amplifier connected to the sample and hold circuit (7), and the error signal output terminal (9) is connected to the second sample and hold circuit.
Outputs an error signal for tracking control.

(Error signal output section formed by 10H filter (3) or buffer amplifier (8), circle, Q2 are first and second sampling pulse input terminals, and sample hold circuit +51, (7) are connected to first and second sampling pulse input terminals. Outputs 2 sampling pulses.

+13 is an adder with one input terminal connected to the rectifier circuit (4), and the other input terminal is connected to the sample and hold circuit (5). The third and fourth sample and hold circuits are connected to the 3rd and 4th sample and hold circuits, uQ is a head switching pulse input terminal into which a head switching pulse whose level changes every time the rotating head is switched, and Qη is an input terminal (the second sampling pulse and Input terminal (This is a sampling pulse selection circuit into which the IQυ head switching pulse is input, and the sample hold circuit G
4) Output a second zero sampling pulse to αG.

・J8) is the operational amplifier Gtsu and resistor (几1), (几2
), a first integrating circuit formed by a capacitor (C1) and connected to a sample and hold circuit tl14).

(2G is an operational amplifier t21), a second integrating circuit formed by resistors (R3), (几4), and a capacitor (C2), and is connected to the sample and hold circuit αυ.

＠ is a switch whose contacts (a) and (b) are connected to the integrating circuits α and cA, respectively, and is switched by the head switching pulse of the input terminal 0Q, and the gain control is performed from the switching piece to the amplifier circuit (2). Output a signal. (c) is a gain control circuit consisting of an integrating circuit (to), (4) and four switches.

The reproduction signals of the two rotating heads, which are output alternately for each track, are output to the filter (3) via the input terminal (1) and the amplifier circuit (2), and from the filter (3) to the rectifier circuit 44. The trace track included in the reproduced signal and the reproduced pilot signal components of two adjacent tracks are output.

By the way, since the tape (T) is set to the recording format shown in Fig. 5, one rotary head, for example, may not be able to read the track (A) in Fig. 2, which shows a part of the recording format shown in Fig. When tracing, first the recording area (in the recording area of the trace track (A)) is traced, and then the recording areas (p) of the two adjacent tracks are traced in order. At this time, if the tracking position does not deviate much, Trace track included in the playback signal (
Since the level of the reproduced pilot signal component of A) is high and the level of the reproduced pilot signal component of the two adjacent tracks is relatively low, the signal outputted from the rectifier circuit (4) to the sample hold circuit (51K) is as shown in Figure 3(a). ), it becomes the reproduced pilot signal component of the trace track (A) during the period T1, and becomes the reproduced pilot signal component of each of the two adjacent tracks during the periods T2 and T3. Identical symbols indicate the same thing.

Furthermore, when the other rotary head traces the track (B) in FIG. ) is traced, the signal output from the rectifier circuit +41 to the sample-and-hold circuit (51) is traced over periods T1 and T2, as shown in FIG. 4(a).
On the other hand, input terminal t
ll), α first . The second sampling pulses are formed based on the reproduction synchronization signal of the recording area (S) of the trace track, and the periods shown in FIG. 3(b) and FIG. 4(b) when the reproduction synchronization signal of the trace track begins to be reproduced , 藺, 72 knees; 1. That is, each time the recording area (p) of the adjacent track on the trailing side of the trace track is traced, a first sampling pulse is formed and input to the input terminal Qll.

In addition, after a predetermined period of time after the first sampling pulse is formed, second sampling pulses are formed and input to each of the morning views 9 and 311 λ in Figures 3(b) and 4(b). It is input to the terminal u2, and at this time, the recording area (p) of the adjacent track on the preceding side of the trace track is traced.

Since the sample and hold circuit (51) samples and holds the output signal of the rectifier circuit (4) at the timing of the first sampling pulse, the sample bold circuit (5) samples and holds the output signal of the rectifier circuit (4) at the timing of the first sampling pulse. Sample the ingredients in bold.

Furthermore, the subtracter (6) includes a sample hold circuit (5)
A subtracted signal of the reproduced pilot signal component of the adjacent track on the trailing side held by the rectifier circuit (4) and the output signal of the rectifier circuit (4) is output to the sample and hold circuit (7).

Since the sample hold circuit (7) samples and bolds the subtraction signal at the timing of the second sampling pulse, the sample hold circuit (7) is connected to the rectifier circuit (4).
The reproduced pilot signal component of the preceding adjacent track in period T1 or T3 is output from , and when the subtracted signal of the subtracter (6) becomes a signal of the difference between the reproduced pilot signal components of the two adjacent tracks, the subtracted signal is output. Hold the sample.

Therefore, a tracking control error signal having the level of the difference between the reproduced pilot signal components of two adjacent tracks is output from the sample hold circuit (7) via the buffer amplifier (8) to the output terminal (9), and the error signal Tracking control is performed by controlling the running phase of the tape ('I') so that the level of 'I' is OK.

On the other hand, the selection circuit α force is based on the level of the head switching pulse of the input terminal uQ, and during the tracing period of one rotary head tracing the track (4), the second sampling pulse of the input terminal Q4 is sampled and held by the sample hold circuit 04). During the tracing period of the other rotary head when the track (B) is shifted to G, the second sampling pulse of the input terminal @ is outputted to the sample and hold circuit OQ.

When the second sampling pulse is output, the adder li, 1 combines the reproduced pilot signal component of the preceding adjacent track outputted from the rectifier circuit (4) and the reproduced pilot signal component outputted from the sample hold circuit (5). In order to output a signal added with the reproduced pilot signal component of the adjacent track on the row side, the sample and hold circuit α is used.

(IQ alternately samples and holds the sum signal of reproduced pilot signal components of two adjacent tracks during the trace period of the other rotary head and outputs the resultant signal.

By the way, the sum of the reproduced pilot signal components of two adjacent tracks included in the reproduced signal of the rotary head hardly changes depending on the tracking deviation, considering crosstalk and franging effects, and the sum of the reproduced pilot signal components of two adjacent tracks included in the reproduced signal of the rotating head hardly changes depending on the tracking deviation, and the tracking recorded on the tape (T) It changes in proportion to the variation in the control pilot signal and the variation in the reproducing ability of the rotary head.

Therefore, the level of the addition signal output from the sample and hold circuits α→, αQ changes in proportion to the above-mentioned variations.

and sample hold circuit u4. The addition signal of θG is
Fluctuations due to noise etc. are removed by the integrating circuits (g) and (e), and the contacts (a) and (b) of the switch (support)
are output respectively.

Furthermore, the switch (a) switches the contact point (a) during the trace period of one rotary head by the head switching pulse of the input terminal qQ.
a) and during the tracing period of the other rotary head, it is switched to contact (b).

And the switch @ is the sample hold circuit (14) a
A gain control signal consisting of an average summed signal, that is, a gain control signal whose level changes in proportion to the above-mentioned variation, is fed back to the amplifier circuit (2), and at this time, the amplification gain of the amplifier circuit (2) is equal to the gain control signal. The level of the reproduced signal output from the amplifier circuit (2) is variable controlled in inverse proportion to the level of the input terminal (1), and decreases as the level of the reproduced signal at the input terminal (1) increases due to the above-mentioned variations; (1) increases as the level of the reproduced signal decreases.

Therefore, from the amplifier circuit (2) to the error signal output section (I
The level of the playback signal output to G is controlled so that it does not change due to the above-mentioned variations, and thereby the tracking control signal is output from the sample hold circuit (7) to the output terminal (9) via the buffer amplifier (8). The level of the tracking error signal is not affected by variations in the tracking control pilot signal recorded on the tape or variations in the reproducing ability of the rotary head, and stable tracking control can be performed with a relatively simple configuration.

In the above embodiment, the amplification gain of the amplifier circuit (2) is controlled every time the rotary head for reproducing tracing is switched - thus preventing signal fluctuations. However, in order to simplify the configuration, for example, a sample hold circuit 0r5. Integrating circuit 120. The switch (A) may be omitted and the gain of the amplifier circuit (2) may be variably controlled only by the addition signal output from the sample and hold circuit OΦ. Only fluctuations in the tracking control error signal are prevented.

In addition, in the above embodiment, the tape (T) with the recording pattern shown in FIG. Of course, the present invention can be applied to various rotary head type tape recorders.

〔Effect of the invention〕

As described above, according to the rotary head tape recorder of the present invention, the reproduced pilot signal components of two adjacent tracks extracted by the error signal output section GO are added by the adder 0.1, and the sample hold signal is output from the adder α. circuit 04),
A sum signal of the reproduced pilot signal components of the two adjacent tracks is output to α, and it is amplified in inverse proportion to the level of the output signal from the gain control circuit (A) to the amplifier circuit (2) K to the sample hold circuit 0→, 0υ. By forming and outputting a gain control signal that variably controls the gain 1 etc. of circuit (2), the tracking control error signal output from the output section 00 is caused by variations in the tracking control pilot signal recorded on the tape. Fluctuations are prevented and stable tracking control can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of one embodiment of the rotary head type tape recorder of the present invention, Fig. 2 is a front view of the tape, and Fig. 3 (
4a and 4b are timing charts for explaining the operation of FIG. 1, and FIG. 5 is an explanatory diagram of the recording format of the rotary head type digital tape recorder. (Slice: amplifier circuit, +IO: error signal output section,
OQ...Adder, 0→, aυ...3rd. 4th sample hold circuit, Kan...Li 1 control circuit, (T)...
・Tape, (A), (B)...Track, (p)
... Recording area for pilot signals for tracking control.

Claims (1)

[Claims] (1) A tape in which each track is provided with an independent recording area for a pilot signal for tracking control, a rotary head whose gap width is set wider than that of each track, and which reproduces and traces the tape, and a reproduced signal from the head. an amplifier circuit that amplifies and outputs the output signal with automatic gain control, and extracts reproduced pilot signal components of two tracks adjacent to the reproduced track included in the output signal of the amplifier circuit, and a level of the difference between the reproduced pilot signal components of the two adjacent tracks. an error signal output section that outputs an error signal for tracking control;
an adder that outputs a sum signal of reproduced pilot control signal components of the two adjacent tracks; a sample hold circuit that samples and holds the sum signal; and a gain of the amplifier circuit that is inversely proportional to the level of the output signal of the sample hold circuit. 1. A rotary head tape recorder comprising: a gain control circuit for forming a gain control signal for variable control.