JPH0626963Y2 - Digital Ode Tape Player - Google Patents

Description

[Detailed Description of the Invention] "Object of the Invention" (Industrial field of application) The present invention samples an audio input signal, performs analog-to-digital conversion, and records a digital signal by obliquely scanning a magnetic tape with a rotary head. The present invention relates to a digital audio tape player which reproduces the recorded data, and in particular, it has a standard speed standard and a low speed standard in which both the rotation speed of the cylinder and the tape running speed are halved with respect to the standard speed standard. The present invention relates to a reproducing apparatus for a head type digital audio tape player (hereinafter referred to as R-DAT).

(Prior Art) Table 1 shows a standard draft of a standard speed standard (hereinafter referred to as SP) and a low speed standard (hereinafter referred to as LP) of R-DAT.

That is, there are an SP that can obtain high-quality sound and an LP that is slightly inferior in sound quality but can record and reproduce for a long time (twice the time of SP).

A device generally considered as an R-DAT reproducing device satisfying such standards is shown in FIG.

This playback device has instructions from the operation unit 1 (PLAY key operation)
Based on the above, the control unit 2 issues an instruction to the capstan servo 3 and the cylinder servo 4, and the predetermined standard speed (2
The cylinder 5 is rotated at 000 rpm and the magnetic tape is run by a capstan (not shown).

Further, the tracking signal is detected and processed by the ATF detection processing circuit 6 and the capstan servo 3 is controlled to accurately trace the recording track of the magnetic tape on which the rotary head 7 provided in the cylinder 5 runs. The reproduction signal extracted by the rotary head 7 is amplified by the head amplifier 8, passes through the reproduction equivalent circuit 9, and is then extracted by the clock extraction circuit 10.
The clock signal is detected at 11 and demodulated 11. Further, by detecting the block synchronization signal 12, the ID code is detected 13, and the memory 1 by the block address of the data is detected.
Writing to 4 is performed while deinterleaving. ID
In the code, there is a bit indicating the LP mode. When this code is detected, the rotation speed of both the capstan and the cylinder 5 is set to 1/2 (1000 rpm) of SP, and at the same time, the reproduction equivalent circuit 9 is used. It is necessary to change the circuit constant of the clock extraction circuit 10. For example, FIG. 6 shows an example of a switching circuit of a conventional reproducing circuit 9, in which a reproducing signal taken out by the rotary head 7 is amplified by a head amplifier 8 and a delay time of 2T1 = T2 is set. Delay circuit 1
5, 16, 17 and SP and LP changeover switch 18,
It is configured to be supplied to the operational amplifier 20 via 19.

An error is detected in the reproduction data written in the memory 14 by the complex computing unit (signal processing unit) 21, and is corrected and corrected.

Further, they are read out in order, D / A converted 22, passed through a low-pass filter, and taken out as an audio output.

(Problems to be Solved by the Invention) In the above-described conventional R-DAT reproducing apparatus, the following points are raised as problems.

That is, as shown in FIG. 5 (a), both SP and LP have the same pattern recorded on the magnetic tape, but the reproduction pulse train (bit train) thereof is S in FIG. 5 (b).
As compared with the output waveform in the case of P, the output waveform of LP has a longer pulse train length during reproduction as shown in FIG. 5 (c). In addition, the pulse frequency band of LP is half as low as that of SP of FIG. 5 (d) as shown in FIG. 5 (e).

Therefore, it is necessary to switch the circuit constants in the reproduction equivalent circuit 9 and the clock extraction circuit 10. For example, as in the reproduction equivalent circuit 9 shown in FIG. Therefore, the delay circuit 17 is additionally required, and there is a drawback that the entire reproduction system circuit becomes complicated. Furthermore, a demand for a reproducing system requires a wider band, which is a problem in cost reduction.

The present invention has been made in view of the above-mentioned drawbacks of the conventional R-DAT playback device.
An object of the present invention is to provide an R-DAT reproducing apparatus that enables the reproduction equivalent circuit and the clock extraction circuit to be shared by SP and LP, and can reduce the error rate.

[Construction of Device] (Means for Solving Problems) The reproducing apparatus of the R-DAT according to the present invention samples an audio input signal, performs analog-digital conversion, and digitally converts the digital signal diagonally on the magnetic tape by the rotary head. A digital audio tape capable of reproducing a standard speed standard of a digital audio tape for scanning and recording and a low speed standard in which both the number of revolutions of a cylinder and the tape running speed are set to 1/2 of the standard speed standard. In the player, a means for rotating the cylinder at the same speed as the standard even though the player is in the reproduction mode state of the low speed standard, and in the state described above, the data is read twice and both the read data are read. On the other hand, a means for detecting an error, and one of the two data for which the error has been detected, which has less error Adopted data in blocks error correction on the data, in which a means for correcting.

(Operation) When recording an audio input signal or the like, the same recording means as in the conventional case is used, but at the time of reproduction, the number of rotations of the rotary head for both SP and LP is the number of rotations at SP. Therefore, the pulse frequency band of LP is also S shown in FIG.
It can be the same as in P, and the reproduction equivalent circuit and the clock extraction circuit can be shared. Also, the same data can be read twice to reduce the error rate.

(Embodiment) An embodiment of an R-DAT reproducing apparatus according to the present invention will be described with reference to FIGS.

In the R-DAT reproducing apparatus according to the present invention shown in FIG. 1, the first difference in the configuration from the conventional R-DAT reproducing apparatus shown in FIG. 4 is that the cylinder 5 rotates in both SP and LP. The same number is used, and the circuit constants of the reproduction equivalent circuit 9 and the clock extraction circuit 10 are shared by SP and LP. The second is that the rotary head 7 traces the same tape pattern twice and the same data is read twice to reduce the error rate. As a result, for example, when the rotary head 7 having a width 1.5 times the track width is mounted on the cylinder 5 having a 90 degree winding of 30φ for reproduction, the magnetic tape tracks shown in FIG. ... against, ',', '...
And the trajectory of the rotary head 7 are obtained, and the reproduction signal thereof is the third
It becomes like FIG. The frequency component of this reproduced signal is
It is the same as during SP playback, and the signal is almost the same as the normal level (SP level), ... The part to be played is generated. This is cylinder 5
Seeing from the rotation of, the feeding amount of the magnetic tape during 1/2 rotation is 1
It becomes such a trajectory because it becomes / 2. Therefore, the switching signal of the rotary head 7 is divided by 2 to obtain the signal shown in FIG. 3 (b). When this signal is H and L, it is demodulated and written in the memories 24 and 25. That is, the same tape pattern is traced twice by the rotary head 7 (the width on which the rotary head 7 is mounted is different), and the same data is read twice. Then, the error detection circuit 26 detects an error and compares the same two blocks in the H section and the L section in FIG. 3B, and when the L has less errors, the data in the L section Otherwise, the data in the H section is transferred to the memory 14 for correction and correction, and the code is corrected and corrected. Therefore, FIG. 3 (a)
of Even in the portion of L having many errors corresponding to, the error rate can be slightly reduced because the data can be correctly read to some extent. The input of the ATF detection processing circuit 6 for detecting the tracking signal is limited to the section H in FIG. 3 (b).

[Advantage of Invention] According to the R-DAT reproducing apparatus of the present invention, the circuit constant of the clock extraction circuit can be shared by SP and LP in the reproducing equivalent circuit, and the error rate can be reduced. It has excellent features such as

[Brief description of drawings]

FIG. 1 shows an embodiment of a digital audio tape player according to the present invention, FIG. 2 shows its tracking pattern, and FIGS. 3 (a) and 3 (b) show its reproduced output waveform. FIG. 4 is a block diagram showing a conventional digital audio tape player, FIGS. 5 (a) and 5 (b),
(C), (d), (e) are conventional tracking patterns, output waveform diagrams, pulse frequency band diagrams, and FIG. 6 is a conventional reproduction equivalent circuit. 3 ... Kipstan servo, 4 ... Cylinder servo 5 ... Cylinder, 7 ... Rotary head 9 ... Equivalent circuit for reproduction, 10 ... Clock extraction circuit 24, 25 ... Memory, 26 ... Error detection circuit

Claims (1)

[Scope of utility model registration request] 1. A standard speed standard of a digital audio tape in which an audio input signal is sampled, analog-to-digital conversion is performed, and a digital signal is obliquely scanned on a magnetic tape by a rotary head to record the standard speed standard. In a digital audio tape player capable of reproducing a low speed standard that is set to 1/2 for both the number of rotations of the cylinder and the tape running speed, it is the same as the standard standard even though it is in the reproduction mode state of the low speed standard. A means for rotating the cylinder at a speed, a means for reading the data twice in the above-mentioned state and detecting an error for both the read data, and an error in the two data for which the error has been detected. Data with less data is adopted in block units and error correction and correction is performed on that data. Digital audio tape player, characterized in that a stage.