JPH03250461A - Digital information signal recording and reproducing device for optical discoid recording medium - Google Patents

Abstract

PURPOSE:To prevent lack of a lead part of a recording signal at the time of performing an additional recording by inserting a signal delay means having a prescribed delay time into a digital information signal transmitting path between an A/D converting means and an encoding means. CONSTITUTION:A digital information signal converted by an A/D converting block 8 into a digital signal is delayed by a prescribed time by a delay circuit 12 set at the time for obtaining an approximately the same delay time as one revolution time of an optical disk 1 for recording information by a delay time calculating circuit 13 to be operated by a track jump signal 6a from a tracking servo block 6, a clock pulse 11b from a system controller 11 and a recording start signal 11c, and is sent to an encoder 7. By this constitution, the recording signal can be supplied to a write processing system after waiting for a write mode that is effective when a trace point of an optical pickup 3 of the write processing system reaches a starting point of a nonrecorded track on an optical disk 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device that digitizes music and video signals, records them on a disk-shaped recording medium, and plays them back, particularly for information that is sent unilaterally such as broadcasting. The present invention relates to a digital information signal recording and reproducing apparatus for an optical disk-shaped recording medium, which is suitable for performing additional recording while selecting desired information from among the information.

[Conventional technology]

2. Description of the Related Art Conventionally, there are recording and reproducing apparatuses that digitize analog signals such as music, video, etc., record them on an optical disk-shaped recording medium, and reproduce the digitized signals.

FIG. 4 shows a conventional device of this type.

In this figure, 1 is a writable optical disc, for example, a write-once optical disc that can be written only - times;
Alternatively, it may be a writeable and erasable magneto-optical disk. A spindle motor 2 rotates the disk, and is controlled to a predetermined rotation speed by a spindle servo block 4. 3 is an optical pickup for reading and writing signals, and a focus servo block 5
By controlling the tracking servo block 6, the focus and position of the beam spot are maintained in an optimal state.

8A and 8B are input terminals, and if the input signal is, for example, a two-channel music signal, the analog signals supplied to the input terminals 8A and 8B are converted into digital signals at the analog/digital conversion block 8. , encoder 7
The signals are subjected to processing such as adding an error correction code, interleaving, modulation, etc., and are recorded on the optical disk l through the optical pickup 3.

On the other hand, the signal read from the disk is demodulated into a correct signal by the decoder 9, and then supplied to the digital/analog conversion block 0, where it is converted back to the original analog signal and output to the output terminals OA and IOB.

Note that the system controller 11 controls the operation of each block in order to perform these writes and reads.

The above is the block configuration of a conventional digital information signal recording/reproducing apparatus using an optical disc.

[Problem to be solved by the invention]

However, when recording continuously on two discs, for example, when copying from other media or recording information from a broadcast as it is, there are no problems with conventional equipment. Although this does not occur, several major problems occur when recording is performed in small intervals, so-called additional recording.

Here, a method for performing additional recording on an optical disc will be explained. In FIG. 6, the solid line portions are already recorded tracks, and the dotted line portions are unrecorded tracks. It is assumed that recording is performed clockwise from the inner circumference to the outer circumference. In the recording start standby state (generally called "pause"), the optical pickup traces in a reading state between the start point A of the unrecorded track and the point A' one track before. In this operation, the system controller 11 reads the time code and address information recorded on the recorded track together with the digital information signal, and sends a track jump command to the tracking servo block 6, so that the optical pickup 3 The light beam is moved from point A to point A'. This operation is commonly called kickback and is performed in CD players and other optical players currently on the market. , as a method for detecting the start point A of this kickback, there is also a method of detecting the disappearance of the playback signal and using it for the track jump command.In this way, in the pause state, the disk 1 rotates at a predetermined speed. Meanwhile, the optical pickup repeatedly traces between points A and A1.

Naturally, when a user tries to start recording at a certain point, the light beam will rarely be located at the starting point A of the unrecorded area, and the disc will rotate and reach point A. The optical pickup cannot be switched to write mode until it arrives. Therefore, in the worst case, input information corresponding to the time of one revolution of the disk cannot be recorded.

For example, when using a writable optical disc that is compatible with a CD, which is a read-only optical disc, the rotational speed is approximately 50 Orpm at the inner circumference, and approximately 50 Orpm at the outer circumference.
Since it is about 20 Orpm, the missing time due to unrecorded input information is about 120 to 300 m5ec. If you start this recording device and then start the side that sends out the human-powered information, there will be no particular problem, but if you try to record the signal from the broadcast, a problem will occur such as the beginning of the information being missing. . To prevent this problem, there is a method in which the trace section of the optical pickup in the pause state is set between points A and A1 instead of between points A and A'. However, in the worst case, with this method, an unrecorded section corresponding to the rotation of the disc will occur, making tracking unstable during playback. Not only that, but the rotation control of the disc becomes unstable, resulting in incompatible discs.

As explained above, with conventional devices, the first part of the information you want to record may be missing, or the current C
D players have problems such as not being able to reproduce them well.

The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to prevent the beginning of a signal from being omitted even when additional recording is performed. An object of the present invention is to provide a digital information signal recording and reproducing device for an optical disc-shaped recording medium, which can reliably record information without using an optical disk.

[Means to solve the problem]

The digital information signal recording and reproducing device for an optical disk-shaped recording medium according to the present invention includes a signal delaying means having a delay amount corresponding to at least one rotation period of the recording medium, and the analog-to-digital conversion means and the encoding means. It is characterized by being inserted into the digital information signal transmission path between the two.

[For production]

According to the present invention, since the recording signal can be delayed from real time by at least a time corresponding to one rotation period of the recording medium and then supplied to the recording medium writing processing system, the optical pickup of the writing processing system The recording signal can be supplied to the writing processing system after the trace point reaches the start point of the unrecorded track on the recording medium and the writing mode is entered, even when additional recording is performed. Therefore, reliable recording is possible without missing even the beginning part of the information signal to be recorded.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an optical disc recording/reproducing apparatus according to an embodiment of the present invention.

In this figure, blocks having the same functions as those in FIG. 5 are indicated by the same numbers.

The digital information signal converted into a digital signal by the analog/digital conversion block 8 is delayed by a predetermined time by a delay circuit 12 and then sent to the encoder 7. The delay amount of the delay circuit 12 is set to an amount that provides a delay time approximately equal to the time required for one rotation of the disk on which information is recorded. For example, if the digital information signal is a Hi-Fi music signal, the sampling frequency is set to 44. 1KHz
, assuming that the number of bits per sample is 16 bits, the digital information signal for two channels is 44.1k×1
6X2+1.4Mbps, or 176.4 bytes/sec. Then, the rotation speed of the disk is
For example, if the speed is 360 rpm, the time for one rotation is about 167 m5ec. Transfer rate 176.4 bytes/
See, to obtain a delay time of 1675 seconds, approximately 2
9.4 requires a byte delay amount. One way to achieve this delayed operation is, for example, by using a random access memory (RAM) system 12, as shown in FIG. In the figure, 12A is a RAM, and writing and reading of data is performed by an R/W control signal output from a read/write control circuit 12E and a write or read address signal output from a data selector circuit 12B.

By the way, the delay operation of digital signals using RAM is as follows.
As is well known, this is achieved by controlling the difference between the data write address and the data read address to an appropriate value. For example, in the case shown in FIG. 2, the output of the counter 12D is used as the data read address, while the write address is set to the output of the counter 2, that is, the read address, and the adder circuit 12C
In this case, the address obtained by adding the value set on the signal line 1B'a is used. Therefore, data selector 1,
A read address and a write address offset by a certain value are supplied as input signals of 2B, and the read address and write address are alternately selected by the signal output from the read/write control circuit 12E. The data is then supplied to the RAM 12A, and a predetermined delay operation is performed. Note that the system controller 11 supplies the signal line 11a with a tarok pulse equal to the data transfer rate supplied to the signal line 8a. For example, it is part of a signal line that supplies the analog/digital conversion block 8, encoder block 7, etc. In addition, in the above explanation, a certain value is added to the read address to obtain the write address, but it goes without saying that the output of the counter 12D can be used as the write address and a certain value is subtracted from this as the read address. The operation is the same, and the circuit configuration is exactly the same.

The outline of the operation of the delay circuit 12 using the RAM has been described above, and the amount of delay in this circuit is determined by the difference (offset) between the read address and the write address. For example, if 32 bytes of RAM is used as the storage capacity, the data transfer rate will be 176.
When 4/<ite/See, maximum 185m5e
A delay time of c is obtained, which sufficiently covers the delay time 1671see mentioned above. On the other hand, if you want to obtain a delay time of exactly 1671 seconds, the read/write address supplied from the signal line 13a
It is sufficient to set the offset amount to 29400 (decimal). In reality, memory addresses are in binary representation, so 29400 (DEC) - 11,1001
A value such as 011,011,000 (B I N),
If the address added to the read address is used as the write address, a delay time of 167 m5ec is obtained.

If a delay circuit such as the one described above is inserted between the analog/digital conversion block 8 and the encoder block 7, the digital information signal is supplied to the optical pickup with a delay of one revolution of the disk or more. Therefore, when trying to start recording, the light beam is not at point A as shown in FIG. 2, so even if the actual start of recording is delayed until it reaches point A due to disk rotation, Since the first part of the input information is not lost, good additional recording is possible. For example, this is a particularly effective means when information is being sent unilaterally, such as in broadcasting, and additional recording is frequently made while selecting from among the information as appropriate.

By the way, in a disc having a constant recording linear velocity, such as a CD, which is a read-only optical disc currently on the market, the rotational speed of the disc is not constant, but has a range of approximately 200 to 500 rpm, as described above. Therefore, the disk rotation time is also approximately 120-300 m.
It changes to 5ec. In this way, when the disk is operated at a constant linear velocity, the slowest rotation speed is 20 Orp.
300 m5ec, which is the disk rotation time at m hours, is
Although it may be set as the delay amount of the delay circuit 12, it is possible to perform additional recording with less waste and high fidelity by controlling the delay amount of the delay circuit in proportion to the rotational speed of the disk.

As a method of changing the amount of delay, the offset value of the address supplied from the signal line 13a described above may be changed in accordance with the rotational speed of the disk. The rotational speed of the disc can be calculated from the relationship between the writing position in the radial direction of the disc and the linear velocity.

2πr τ: Time for nib screw rotation (m5ec) r: Writing position in the radial direction (am) ■Two-line velocity (m/sec) The value just calculated from this formula is used for writing and reading the RAM in Figure 2. By using the signal line 13H that provides an offset from the address, a desired amount of delay corresponding to the rotational speed of the disk can be obtained.

Furthermore, as a method for performing additional recording with higher precision, in the recording standby state, the actual disk rotation speed and the time to the recording start point A are measured, and the delay circuit 12
A method for controlling the amount of delay will be explained.

In FIG. 1, the delay amount calculation circuit 13 in this method
is operated by a track jump signal 6a from the tracking servo block 6, a clock pulse 11b and a recording start signal 11C from the system controller 11, and this output is sent to a delay circuit via a signal line 1.3a. 12 to control the amount of delay.

FIG. 3 shows a more detailed block diagram of the delay amount calculation circuit 13, and FIG. 4 shows its simple timing chart.

In FIG. 3, a track jump signal (kick pulse) is supplied to the signal line 6a, and this signal is connected to the LOAD control terminals of two counters 13A and 13B. The counter 13A is an up counter, and the counter 13B is a down counter. As shown in the timing chart of Figure 6, (b)
When the kick pulse is input, the counter 13A.

A certain value is loaded into each of the 13B. For example, the up counter 13A has a certain small value (0 is also fine).
α is set, and the previous count value of the counter 13A is set in the down counter 13B. That is, the counter 13A measures the disk rotation time, and the maximum value represents the disk rotation time (actually, +α is added).

On the other hand, when the down counter 13B is loaded with the maximum value of the counter 13A, that is, the disk rotation time,
It is counted down to approximately the value of α, and the disk rotation time is loaded again with the next kick pulse. In the recording standby state, such a state is repeated as shown in FIGS. 4(c) and 4(d).

Here, as shown in FIG. 4(e), when a recording start command is issued at a certain point in time, a certain value τ of the down counter 13B is recorded in the register 11C. This value is
In FIG. 6, it means the time it takes for the light beam to reach the recording start point A from the current point (between A and A'). Therefore, if the output of the register 11C is used as a delay amount control signal for the delay circuit, highly accurate delay amount control becomes possible. The reason why the counter 13A is set to a small value α is to prevent the down counter 13B from underflowing due to variations in the rotational speed of the disk.Another method is to set the down counter 13B to a small value α. When the value α reaches a small value, the countdown operation may be stopped. Further, as for the clock pulse 11b inputted to the counter, the measurement accuracy improves when the frequency is as high as possible, but for example, it is sufficient if the clock pulse 11b has the same data transfer rate as the signal line 11a in FIG. 2.

By using the delay calculation circuit described above and controlling the delay amount of the delay circuit by considering not only the rotational speed of the disk but also the time to the recording start point, extremely high-precision additional recording is achieved. be done.

As explained above, since the recording signal can be delayed from the real time by at least a time corresponding to one rotation period of the disk 1 and then supplied to the writing processing system for the disk 1, the optical pickup 3 of this writing processing system A recording signal can be supplied to the writing processing system after the trace point reaches the start point of an unrecorded track on the recording medium and enters the writing mode. This enables reliable recording without missing even the beginning of the information signal.

As a result, additional recording can be performed continuously without generating an unrecorded portion, so that it is possible to provide a write-once optical disc device that is particularly compatible with read-only optical discs, such as CDs.

Furthermore, in the future, when higher density and longer operation times will be achieved due to the development of short wavelength semiconductor lasers, etc., it will become more effective, especially for low-speed rotating disks.

Furthermore, by slightly increasing the delay time, it is possible to prevent a portion of information from being omitted due to a delay in the manual recording start operation.

〔Effect of the invention〕

As explained above, according to the present invention, the recording signal can be supplied to the recording medium writing processing system with a delay of at least a period of time corresponding to one rotation period of the recording medium from the real time. A recording signal can be supplied to the writing processing system after the trace point of the optical pickup of the processing system reaches the start point of an unrecorded track on the recording medium and enters the writing mode, and when performing additional recording. Even if there is an information signal to be recorded, the head part of the information signal to be recorded can be recorded reliably without being omitted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the recording/reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing the configuration of a RAM system that constitutes the delay means and whose delay amount is variable, and FIG. 3 is the delay amount thereof. FIG. 4 is a block diagram of a delay calculation circuit that calculates and controls the delay amount, FIG. 4 is an operation time chart thereof, FIG. 5 is a block diagram of a conventional recording/reproducing apparatus, and FIG. 6 is a schematic diagram of an optical disk track. 1... Optical disk, 2... Spindle motor, 3.
...Optical pickup, 4...Spindle servo pro.
Tsuk, 5...Focus Servo Pro Tsuk, 6...
Tora soking servo block, 7... encoder,
8...Analog/digital conversion program, 9...Decoder, 10...Digital/analog conversion program, 11...System controller, 12...Delay circuit, 13...Delay amount calculation circuit.

Claims (1)

[Claims] Analog-to-digital conversion means for converting an analog input signal into a digital information signal, and encoding for performing encoding processing on the digital information signal from the analog-to-digital conversion means to match the format of a recording medium. and a digital information signal recording/reproducing apparatus for an optical disc-shaped recording medium for recording the encoded digital information signal on the recording medium, the apparatus having a delay amount corresponding to at least one rotation period of the recording medium. A digital information signal recording and reproducing apparatus for an optical disc-shaped recording medium, characterized in that a signal delaying means is inserted in a digital information signal transmission path between the analog-to-digital converting means and the encoding means.