JPS62120635A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To reproduce always precisely the recording information of a recording medium by detecting the threshold level of a binary encoding circuit for shaping the waveform of a reproducing signal and adjusting recording intensity in accordance with the threshold level to record information in the recording medium. CONSTITUTION:A microcomputer 13 constitutes a threshold level detecting circuit TD together with an integrating circuit 10, a comparator 11, a latch circuit 12, and peak holding circuit 18 to control these circuits A D/A converter 15 and a recording intensity control 16 constitute a recording intensity adjusting circuit RC to control the recording intensity at the succeeding recording of information in the recording medium 1. Since the threshold level of the binary encoding circuit 4 at the reading of the information from the recording medium 1 is appropriately controlled by the threshold level setting circuit LC and the recording intensity at the recording of information in the recording medium 1 is corrected on the basis of the appropriate threshold level, the information can be recorded/reproduced under stable state without the influence of a recording element 7 to be exerted upon the or the like of the recording intensity or the sensitivity of the recording medium 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides t+Vf for information recording media such as optical discs.
The present invention relates to an information recording and reproducing device that properly records and reproduces information.

[Prior art]

When reproducing recorded information from an information recording medium (hereinafter referred to as a recording medium) such as an optical disk, the recorded information is reproduced from the recording medium by a reproducing element, and successive signals are waveform-shaped at an appropriate threshold level. By the way, the level of the signal reproduced from the recording medium changes depending on the recording intensity of the recording element that records information on the recording medium or the sensitivity of the recording medium, so the threshold level for waveform shaping is fixed. (O) Waveform shaping may cause bit/nod errors.

Therefore, a threshold level setting circuit is provided that adjusts the threshold level of the 2 (Il!I conversion circuit) for waveform shaping in accordance with the reproduced signal.

[Problem that the invention seeks to solve]

However, even when adjusting the threshold level as described above, if the recording intensity is extremely different from the appropriate recording intensity of the recording medium, there is a risk that the recorded information will not be reproduced accurately. There is.

[Means for solving problems]

In view of the above-mentioned circumstances, the present invention provides a threshold level detection circuit that detects a threshold level from the output of a threshold level setting circuit that sets the threshold of a binarization circuit that performs waveform shaping of a reproduced signal. and a recording strength adjustment circuit that controls the recording strength of information, and a threshold level detection circuit that always reproduces accurate information by adjusting the recording strength in relation to the obtained threshold level. The purpose of the present invention is to provide a Shipir information recording and reproducing device.

The present invention includes a binarization circuit that shapes the waveform of a reproduced signal of information recorded on a recording medium, and a threshold level setting circuit that outputs a threshold level of the binarization circuit for each C according to the level of the reproduced signal. In an information recording and reproducing apparatus, the information recording and reproducing apparatus includes a threshold rail detection circuit comprising an integrating circuit that integrates the output of the 4-if threshold level setting circuit and a comparator that compares the output of the integrating circuit with a reference signal; and a recording intensity adjustment circuit for controlling the recording intensity of the recording medium, and controls the recording intensity adjustment circuit based on the output of the threshold value detection circuit to adjust the recording intensity to the recording medium appropriately. It is characterized by the way it is structured.

(Function) The output of the threshold level setting circuit, that is, the threshold level, represents the level of the reproduced signal, but when detecting the threshold level of this binarization circuit and recording information, By adjusting the recording intensity on the recording medium in relation to the detected threshold level, it becomes possible to accurately record and even reproduce information that is not affected by variations in sensitivity of the recording element and the recording medium.

〔Example〕

The present invention will be described in detail below based on drawings showing embodiments. FIG. 1 is a block diagram showing the configuration of an information recording/reproducing apparatus according to the present invention, and FIG. 2 is a waveform diagram for explaining its operation.

In FIG. 1, ■ is a recording medium such as an optical disk on which information such as a text 1 image is recorded, and the information recorded on this recording medium 1 is converted into an analog signal by a reproduction element 2 (however, the recorded information itself is digital Information) is played. This reproduced signal is amplified by a preamplifier 3, inputted to one terminal of a binarization circuit 4 for waveform shaping, and converted into a binary signal with steep rises and falls. The signal whose waveform has been shaped by the binarization circuit 4 is input to a memory (not shown) provided at the subsequent stage, and a first minimum bit length or less detection circuit that detects the pulse width of the "0" focus. The signal is input to a second minimum bit length or less detection circuit 7 which detects the pulse width of the 6 and "1" bits. These first. The second minimum pitch 1-long side bottom detection 6.7 generates an output when it detects a pulse of "0" or "1" less than the shortest pulse width of 9 volumes. The outputs of the respective minimum bit length or less detection circuits 6 and 7 are the up and down counters 8,
It is input to each down counter terminal. The output of the amplifier down counter is input to the D/A converter 9, converted to an analog signal, and input to the 10 terminal of the MIF binary conversion circuit 4, which serves as the threshold level of the other circuit 4.

1st as above. second minimum focus length or less detection circuit 6;
7. The structure of the threshold level setting circuit LC consisting of an amplifier, down converter 8, and D/A converter 9 is the same as the conventional one, and the threshold level is relatively low (or high) with respect to the reproduced signal around 1. If it is in the opposite direction, the pulse width of the “0” (or “1”) bit becomes shorter, and the first (or second) minimum bit length or less detection circuit 6 (or 7) detects this. The up/down counter 8 is incremented (or decremented). Then, the output of the D/A converter 9, that is, the threshold level, is corrected to increase (or decrease) by that amount, and the threshold level approaches the appropriate value of 4+fi.

The output of the threshold level setting circuit LC is also input to an integrating circuit 10 consisting of a resistor R, a capacitor C, and an operational amplifier OP. The output of the integrating circuit 10 is the comparator 1
1 is entered.

The output signal of the preamplifier 3 is sent to a peak hold circuit 1.
8 to the comparator II of the threshold level detection circuit RD, and the output of the comparator 11 is input to the launch circuit 12. Further, a discharge switch 14 is connected between the terminals of the capacitor C.

The microcomputer 13 has an integrating circuit 10. Comparator IL latch circuit 12 and peak hold circuit 1
8 constitutes a threshold level detection circuit TD, and performs these controls. In other words, as shown in FIG.
At the same time, the switch 14 is turned off as shown in Figure 2 (bl). Then, the integrating circuit IO ratio output increases as shown in Figure 2 (fbl), and the peak hold circuit 18 also holds the peak value during this period. Hold it.
Prior to turning on the switch 14, the latch circuit 12
As shown in Figure (C), a latch signal is given to the latch circuit (2) to latch the output of the comparator 11 at that time. The microcomputer 13 is a latched launch circuit 1
2, that is, the comparison result between the average value of the threshold level during the check period and the maximum level of the reproduced signal during the same period, is read out, and a signal for commanding the optimum recording level is issued accordingly. This signal is D/A converter 1
5 to the recording intensity control device 6.

The D/Δ converter I5 and the recording intensity control I6 constitute a recording intensity m alignment path RC, and this recording intensity adjustment circuit RC controls the recording intensity when recording on the recording medium l next.

With this configuration, the threshold level of the binarization circuit 4 when reading information from the recording medium 1 is properly controlled by the threshold level setting circuit LC, and the threshold level is controlled based on the appropriate threshold level. Since the recording intensity when recording information on the recording medium 1 is corrected, the recording and reproduction of information is stable without being affected by variations in recording intensity or sensitivity of the recording medium I by the recording element-7. It will be held every time.

In the above embodiment, the output of the peak hold circuit 18 related to the level of the reproduced signal is used as a reference for comparing the threshold level in the comparator 11, but the output is not limited to this, and -C may also be used using an appropriate fixed value. . However, if the peak value of the reproduced signal is used as in the embodiment 4.1, there is an advantage that the recording intensity can be set without being influenced by factors specific to one medium, such as the reflectance of the recording medium l.

[Young fruit]

As described in detail above, the present invention provides two methods for waveform shaping a reproduced signal.
(By detecting the threshold level of the conversion circuit to 1 and recording information on the recording medium by adjusting the recording intensity in relation to this threshold level, the recorded information on the recording medium is It is possible to provide a highly accurate information recording and reproducing device that can always reproduce accurately.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an information recording and reproducing apparatus according to the present invention,
FIG. 2 is a waveform diagram of each part in FIG. 1. 1... Information recording medium 4... Comparator 10.
...Integrator circuit LC...Threshold level setting circuit TD
...Threshold level detection circuit 11C...Recording intensity adjustment circuit Applicant Sanyo Electric Co., Ltd. Agent Patent attorney Noboru Kono/f Figure 1 $2I21

Claims (1)

[Claims] 1. A binarization circuit that shapes the waveform of a reproduction signal of recorded information on a recording medium, and a threshold level that outputs a threshold level of the binarization circuit according to the level of the reproduction signal. a threshold level detection circuit comprising an integrating circuit that integrates the output of the threshold level setting circuit and a comparator that compares the output of the integrating circuit with a reference signal; and a recording intensity adjustment circuit for controlling the recording intensity of information, and configured to control the recording intensity adjustment circuit based on the output of the threshold level detection circuit to make the recording intensity on the recording medium appropriate. An information recording and reproducing device characterized by: 2. The information recording and reproducing apparatus according to claim 1, wherein the reference signal is a peak value of the signal input to the binarization circuit.