JPS6260729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a duplicating method and apparatus for producing a recorded tape, and more particularly to a method and apparatus for reproducing an optical disc recorded at a low rotation speed and recording it on a tape running at a high speed. Regarding equipment.

2. Description of the Related Art Conventionally, a high-speed recording device for dubbing called a duplicator has been used to mass produce recorded tapes such as music tapes and language learning tapes.

This conventional duplicator is comprised of a master playback device and a slave recording device.

To explain this with reference to FIG. 1, a master playback device 1 includes a printed mother tape 2 which serves as a signal source for audio signals recorded on a recorded tape.
is wound from the supply reel 3 onto the take-up reel 4 and travels at high speed, supplying the reproduced high-speed audio signals to the plurality of slave recording devices 5a, 5b, . . . 5n. 6 unrecorded tapes are included in the recording device for recording.
a, 6b...6n are supply reels 7a, 7b...
It is wound from ...7n onto take-up reels 8a, 8b...8n, and is running at high speed at the same magnification as the print mother tape 2. By recording the supplied high-speed audio signal, the print mother tape 2
A large quantity of recorded tapes with the same recording content can be produced in a short period of time. Note that some master playback devices have an endless loop of printed mother tape that circulates at high speed, but the principle is the same.

In the duplicating apparatus described above, the quality of the final product, the recorded tape, is determined by the quality of the signal reproduced from the printed mother tape. In particular, printed mother tape
In a master playback device, the tape is run at high speed while coming into contact with many running guide surfaces, including the magnetic head, and is used repeatedly, resulting in deterioration, damage, cutting, etc., resulting in a decline in quality and defects in the recorded tape. For this reason, in general, the original master tape that has been created is not used as the print mother, but the mother tape is duplicated based on the master tape and sent to the print factory, where the print factory further prints multiple prints from the mother tape. They mass-produce recorded tapes by duplicating the mother tape and running it through a master playback device.

Therefore, in addition to the need for expensive spare printed mother tapes, the recording quality of printed mother tapes that are made by duplicating them is of course lower than that of the master tape, and it is inevitable that they will deteriorate as they are repeatedly run. There are drawbacks such as.

The main object of the present invention is to provide a duplicating method and device that eliminates the above-mentioned drawbacks.

In other words, the original audio signal can be reproduced and supplied to the slave recording device without degrading its quality, and since the means of reproduction is contactless, it will not deteriorate or be damaged even after repeated use, and therefore can be easily replaced. It is an object of the present invention to provide a novel duplicating method and apparatus that do not require any spare parts for recording tapes and are comparable in terms of being able to produce a large quantity of recorded tapes in a short period of time.

A feature of the present invention is that an optical disk is used as a print mother, an optical disk playback device is used as a master playback device, and when recording the original signal on the optical disk, the disk is rotated at a low speed to convert audio signals into analog audio signals. The digital signal obtained by digital conversion is recorded as the original signal, and when the optical disk is played back as a print mother, the disk is rotated at high speed and played back in the form of a high-speed digital signal.
By digital-to-analog converting this signal into a high-speed audio signal and supplying it to a recording device that runs unrecorded tapes at high speed, it is possible to efficiently produce high-quality recorded tapes with stable quality. It is meant to be.

The details of the present invention will be explained below with reference to FIGS. 2 and 3.

FIG. 2 is a system diagram showing an example of the configuration of an apparatus for explaining the duplicating method according to the present invention.

In the figure, 9 indicates a playback device for playing back audio signals from the original master tape 10, but this is not necessarily limited to this.
In general, it can be thought of as an audio signal source that supplies an original audio signal. The original audio signal supplied from the audio signal source 9 is converted into a digital signal by the PCM encoding circuit 11, and supplied to the optical disc recording device 12, where it is recorded on the optical disc 13 set therein. Record. At this time, the optical disk is rotated as slowly as possible within the range allowed by the recording density, and signals are recorded at, for example, 100 revolutions per minute. The optical disc 13 on which digital signals have been recorded in this manner is sent to a printing factory, where the optical disc 13 is set as a print mother in an optical disc reproducing device 14, and the recorded digital signals are reproduced. However, at this time, the optical disk is rotated as fast as the response speed of the reproduction system allows, and the signal is reproduced at, for example, 3,600 revolutions per minute. In this way, a high-speed digital signal that is 36 times faster than the original digital signal is played back from the optical disc playback device 14, so if this signal is converted into an analog signal by the PCM decoding circuit 15, the original audio signal is You can obtain high-speed audio signals that are 36 times faster. This signal is supplied to a plurality of slave recording devices 5a, 5b...5n, and in the slave recording devices, unrecorded tapes 6a,
6b......6n, in this example, while running at 36 times the normal tape speed,
If the supplied high-speed audio signal is recorded, a recorded tape with the same recording content as the master tape 10 can be produced with 36×n times the efficiency.

Now, although it is believed that those skilled in the art have already sufficiently understood the above explanation, some supplementary explanation regarding optical disks will be added below.

FIG. 3 is a cross-sectional view showing the principle and structure of an optical disk used in the present invention. FIG. 3A shows the basic structure, and FIG. 3B shows an example of an applied structure. In the figure, 1
6 is a transparent disk serving as a substrate, and has a center hole 17 for fitting into the center shaft of the turntable during use.
is open. The basic structure of an optical disk is that a low melting point metal is vapor-deposited on the back surface of the transparent substrate 16 to form a recording thin film 18. When focused, the thin film in that area instantly evaporates due to heat, creating a small hole called a bit.

Therefore, by turning the laser beam on and off while rotating the disk, it is possible to record signals in the form of intermittent long and short bit strings. When reproducing a signal recorded in this way, if the laser beam is weakened and traced to the extent that it is reflected without causing any thermal change to the recording thin film 18, the reflected light will be attenuated at the bit area. By detecting changes in the intensity of reflected light, recorded signals can be reproduced. laser light 20
Since the condenser lens 19 can focus the light into a small light spot with a diameter of 1 micron or less, it is possible to record at a much higher density than with magnetic disk systems.

By the way, in addition to its role as a substrate constituting the disk, the transparent substrate 16 protects the recording surface (reflective surface) of the recording thin film 18, and also protects against the effects of dirt, dust, fingerprints, etc. that adhere to the surface during use. The focus effect plays an important role in reducing this and making the disk easier to handle. Recording thin film 1
8, a protective film 21 is actually necessary to prevent damage and oxidation from the back side. An example of an applied structure that skillfully handles this is shown in FIG. The space 24 is filled with nitrogen gas, etc., and the recording thin film 1 is
8, and constitutes a double-sided recording type optical disc.

As mentioned above, if you use an optical disk, the bit resolution can be reduced to 1 micron or less, so if you want to record digital information using an optical disk, it is easy to reduce the recording density in the longitudinal direction to 1 micron per bit. be. Therefore, for example, on a circumferential track with a diameter of 20 cm, an amount of information of π×20×10 ⁴ μm/track÷1 μm/bit≈0.63×10 ⁶ bit/track can be recorded. On the other hand, as a PCM code structure that can faithfully transmit audio signals,
For example, sampling frequency 35KHz, quantization bit number
If 12 bits and coding redundancy of 1.2 are used, the amount of information per second is 35 KHz x 12 bits x 1.2 ≒ 0.5 x 10 ⁶ bits/sec. If the audio signal is stereo,
Even if information for channels is multiplexed and transmitted in a time-division manner, the transmission rate may be twice that of the above, that is, 1×10 ⁶ bits/sec.

Therefore, in order to record that amount of information on the circumferential track with a diameter of 20 cm, (1×10 ⁶ bit/sec) ÷ 0.63×10 ⁶ bit/track) ≒1.6 track/sec≒100 track/ It will be understood that it is sufficient to rotate the optical disk at 100 revolutions per minute. Furthermore, if the signal recorded in this way is reproduced at 3600 revolutions per minute, the amount of information per second at the photodetector is 36 × 10 ⁶ bits/second.
The amount of information per second in the sec digital-to-analog converter is only the net information bits for one channel, so it is 35KHz x 12 bits x 36 times ≒ 15 x 10 ⁶ bits/sec, which can be processed with the current technology level. range.

Since the present invention is constructed as described above, it is possible to eliminate the problem of deterioration and damage of the printed mother tape due to repeated use, which was the biggest drawback of the conventional duplicating method. In other words, since the optical disk that serves as the print mother can reproduce signals without contact,
Even after extremely harsh and repeated playback, there is no deterioration or damage, and the original signal quality is always maintained.

Therefore, a print mother can be created directly from the master tape without the need for a spare for replacement, so there is no deterioration in recording quality due to repeated duplication in the middle.

Another feature of the present invention is that the audio signal is
It uses a system that encodes and transmits the data. As a result, the original audio signal can be reproduced and supplied to the recording device for recording without degrading the quality of the original audio signal, which has a remarkable effect on the purpose of producing high-quality recorded tapes.

In addition, since the print mother is disk-shaped, it can be recovered quickly during repeated playbacks, the repeat interval can be easily controlled if necessary, and storage is easy. ing.

In order to efficiently produce recorded tapes, we developed a system that records on optical discs at low speeds and plays them at high speeds.
Efficiency comparable to traditional duplicator systems can be obtained.

Furthermore, as mentioned above, considering that factors inhibiting production such as production interruptions due to occurrence of defects and replacement with spare mothers are removed, productivity is improved more than the apparent figure.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional duplicating device, Fig. 2 is a system diagram showing the configuration of a duplicating device for explaining the duplicating method according to the present invention, and Fig. 3 A and B are used in the present invention. 1 is a cross-sectional view showing the principle and structure of an optical disk, in which A is an example of its basic structure and B is an example of an applied structure. 1 is a master playback device, 5a, 5b......5n
is a recording device for slave, 9 is an audio signal source, 11 is a
PCM encoding circuit, 12 is an optical disk recording device,
13 is an optical disc, 14 is an optical disc playback device,
15 is a PCM decoding circuit.

Claims (1)

[Claims] 1. An audio signal to be recorded is converted from analog to digital, the converted digital signal is recorded on an optical disc at low speed rotation, the optical disc recorded at low speed is played back at high speed rotation, and the audio signal is reproduced at high speed rotation. A method of converting the output signal from digital to analog, recording the converted analog signal on a tape running at high speed, and duplicating the audio signal. 2. Means for converting the audio signal to be recorded from analog to digital; means for recording the output signal of the converting means on an optical disk at low rotation speed; means for reproducing the optical disk recorded at low speed at high rotation speed; and means for reproducing at high speed rotation. An apparatus for duplicating an audio signal at high speed, comprising means for digital-to-analog conversion of the output signal and means for recording the output of the digital-to-analog conversion means on a tape running at high speed.