JPH0298854A - Tracking control circuit for rotary head type digital tape recorder - Google Patents

Abstract

PURPOSE:To reduce the power consumption by providing a sample-hold circuit which holds the tracking error signal of a tracking control circuit and a circuit which cuts off a circuit bias voltage other than a logic circuit which outputs at least sampling pulses. CONSTITUTION:A detection signal 26 obtained by a tracking area detection part T is used to control 1st - 6th transistors TR1 - TR6 and an 8th transistor TR8 for controlling bias voltages of a regenerative amplifier 1, a low-pass filter circuit 2, an envelope detector 3, a 1st sample-hold circuit 4, a subtracter 8, an equalizer circuit 5, and a zero-cross comparator 6. Then when the detection signal 26 is high, namely, when a head traces a part other than a tracking area, a 10th TR10 is turned on the ground a source voltage Vcc from a 11th TR11 and the TR1 - TR6 and TR8 turn off to cut off the bias voltages. Consequently, the power consumption is reducible and the life of a battery is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a tracking control circuit for a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT).

(B) Conventional technology Conventionally, tracking control of a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT) has adopted an area-divided ATF method. A tracking area is formed at the trace start end and trace end of each track of the tape to be helically scanned, and each tracking area has a pilot area where a pilot signal for tracking control is recorded and a pilot area where a pilot signal for tracking control is recorded. A 4-track complete type that has a sync area in which a sync signal for setting the sampling timing is recorded, and the frequency of this sync signal is differentiated for each track, and the area length is also differentiated for every 2 tracks. I have to. That is, such a four-track complete tape pattern is
As shown in the figure, fl is 130.67 and Ht
f2 is a 522.67 Hz sync signal, f3 is a 784 Hz sync signal, f4 is a 1°568 Mtlx cancellation signal, and these sync signals are divided into 0.5.1 blocks every two tracks. The area length has been changed.

Therefore, when a tape on which such a tape pattern has been recorded is played back using two rotary recording/playback heads whose head width is larger than the track width, a sync signal is detected from the playback output of the rotary heads. Based on the timing, the crosstalk components of the pilot signals reproduced from the pilot areas of the left and right adjacent tracks (hereinafter referred to as pilot side lead signals) are sampled, and the levels of both side lead signals are compared and detected to determine the level. By supplying the difference as a tracking error signal to the capstan motor control section, tracking control during playback (tape running control so that this signal becomes zero) is performed. Specifically, the tracking control circuit has a configuration as shown in FIG. 4. For example, when the starting end of a track is reproduced and traced by one of the recording/reproducing rotary heads, the reproduction output of this rotary head is Playback amplifier (1)
After being amplified by the pilot signal, the pilot signal is supplied to a low-pass filter circuit (2) for extracting the pilot signal.

The pilot signal components obtained from this low-pass filter circuit (2) are, as shown in FIG. and a pilot side read signal Pt from. The pilot signal component extracted by the low-pass filter circuit (2) in this manner is envelope-detected by an envelope detector (3) and then supplied to a first sample-and-hold circuit (4).

On the other hand, a reproduction signal from a rotary head for recording and reproduction is waveform-equalized by an equalizer circuit (5) and then converted into a digital signal by a zero-cross comparator (6). Then, the logic circuit (7) digitally processes this signal, detects the sync signal as shown in FIG. ). Therefore, in the first sampling and hold circuit (4), the pilot side read signals P and I are held by this sampling pulse SP1, and the pilot side read signals PR and P
The difference in t is transferred from the subtracter (8) to the second sample and hold circuit (
9). At this time, the fifth
A sampling pulse SP2 shown in the figure is supplied to a second sample and hold circuit (9). Therefore, by this sampling pulse SP2, the second sample hold circuit (9
), the difference between the pilot side read signals PR and PL is held and output, and this output signal is supplied to the capstan motor control section as a tracking error signal.
Tracking control will be performed.

Regarding tracking control, for example, Japanese Patent Application Laid-Open No. 61-4
There is one described in Publication No. 2768 (GIIB 15/467).

(c) Problems to be Solved by the Invention In the tracking control method as described above, a tracking error signal is obtained from the reproduced signal only during the period when the rotary head traces the tracking area, and during the period when the rotating head traces the area other than the tracking area. Only the signal is maintained. In other words, the tracking control circuit is actually working by
Since it is only the period during which the tracking area is traced,
It is not necessary to keep the tracking control circuit running all the time, which is a heavy burden, especially in applications where low power consumption must be considered.

(D) Means for Solving the Problems The present invention includes a circuit for detecting a tracking area recorded on each track of a tape, a sample hold circuit for holding a tracking error signal of a tracking control circuit, and outputting at least a sampling pulse. R-D equipped with a circuit that cuts off circuit bias voltage other than logic circuits
Provides an AT tracking control circuit.

(E) Effect According to the above means, during the period when the rotary head traces the tracking area, a bias voltage is applied to all the circuits constituting the tracking control circuit in order to obtain the tracking error signal from the reproduced signal, and the area other than the tracking area is During the tracing period, the circuit bias voltage of the tracking control circuit other than the sample hold circuit that holds the tracking error signal and the logic circuit that outputs the sampling pulse is cut off.

(f) Embodiment An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration, parts that overlap with the conventional one are omitted, and parts added to the conventional block shown in FIG. 4 will be explained.

In the figure, (21) is a counter circuit, and the clock terminal (22) is connected to the R-DAT system clock 9.
, 408MHx divided by 1/7□0 is input. (23) is a reset signal generation circuit,
A second sampling pulse (SF3>) is input, and the counter circuit (21) is reset at that timing.

The counter circuit (21) performs counting using the clock based on the second sampling pulse (SF3), and the counter times IY! When the output of <211 is decoded by the decoder (24), a tracking error detection signal as shown in FIG. 2(C) is obtained. That is, R-
Since the output position of the second sampling pulse (SF3) is known from the DAT tape format (see Figure 3), the position of the tracking area can be accurately determined by counting based on the second sampling pulse (SF3). It is.

However, due to dropout etc., the second sampling pulse (
SF3) is not obtained, the counter circuit (2
1) Reset using its own count value. Furthermore, if the rotational speed of the Schilling is not constant, such as at the time of rising, the position where the second sampling pulse (SF3) appears is very inaccurate, so the counter circuit (2
1) is reset by the cylinder lock signal (25) and the cylinder lock signal at that time is in a high state) so that the counting operation is not performed. Further, the tracking area detection signal (26) is the second sampling pulse (SF3
) It is necessary to set the position determined to be the tracking area with a sufficient margin, taking into account delay and jitter. Counter times F#1 (21
), reset signal generation circuit (23) and decoder circuit (
The tracking area detection section (T) consisting of the three circuits 24) is also used as a tracking area detection method during recording/playback switching during after-recording.

The detection signal (26) obtained by the tracking area detection section (T) causes the regeneration amplifier (1), the low-pass filter circuit (2), the envelope detector (3), the first sample and hold circuit (4), and the subtracter ( 5), the first to sixth transistors (Tr
l), (Tr21, (Tr3), (Tr4), Itr
5), (Tr61 and the eighth transistor (Tr81) are controlled. When the detection signal (26) is high, (
When the head is tracing an area other than the tracking area), the 10th transistor (Triθ) is turned on, and the power supply Vcc from the 11th transistor (Trll) is grounded, and the transistors (Trl), (Tr
2), (Tr3), (Tr4), (TR5), (T
r6) and (T r 8 ) are turned off and the bias voltage is cut off. Next, while tracing the tracking area, the detection signal becomes low, and the tenth transistor (TrlOl also becomes low, and the transistors furl), (Tr2), (Tr3), (Tr4
), (Tr51. (Tr6) and (Tr8) are in the on state and the bias voltage is not cut.

Incidentally, since the second sample and hold circuit (6) must always hold the tracking error voltage, the bias voltage is kept applied. Also, logic times IY
! (91 is also always operated with a bias applied because it is necessary to maintain the state of the sync sequence etc.

(G) Effects of the Invention According to the present invention, when the rotating head traces an area other than the tracking area, current consumption can be reduced by cutting off the bias voltage of unnecessary circuits in the tracking control circuit. This makes it possible to extend the life of the battery in the battery, which is extremely beneficial.

Furthermore, since the tracking control circuit is not operated during the period when the head loading other than the tracking area is being traced, a tracking error signal is not sent out using a sync signal obtained outside the tracking area, and the tracking control operation is prevented. Improved reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the tracking control circuit of the R-DAT of the present invention, and FIG. 2 is a diagram showing the timing of the envelope signal, head switching signal, second sampling pulse signal, tracking area detection signal, and cylinder lock signal. Figure 3 is a diagram showing the tape pattern of R-DAT,
FIG. 4 is a block diagram showing a conventional tracking control circuit, and FIG. 5 is a timing diagram of various signals for explaining the tracking control circuit. (4), (9)...sample hold circuit, (7)...
...Control logic circuit, (T) ...Tracking area detector, (Trl), (Tr2), (Tr
3), (Tr4), (Tr5), (tr6), (Tr8
), (TrlO), (Trll) - bias voltage cutoff transistors.

Claims (1)

[Claims] (1) Each track of the tape that is helically scanned by a rotating head is divided into a recording area where at least digital information is recorded and a tracking area where information for tracking control is recorded, and tracking is performed during playback. A rotary head digital audio tape recorder that performs tracking control based on tracking error signals obtained in the area includes a circuit that detects the tracking area recorded on each track of the tape and a tracking control circuit that holds the tracking error signal. A tracking control circuit for a rotary head type digital audio tape recorder, characterized in that a circuit for cutting off bias voltage of circuits other than a sample hold circuit and a logic circuit that outputs sampling pulses is provided.