JPH01102773A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To offer convenience on an operation to a user by detecting the maximum level point of a reproducing signal read from a disk by setting reproducing speed at maximum. CONSTITUTION:A device the reproducing speed of which switchable by switching the rotational speed of the disk 12, and the maximum level of the reproducing signal read from the disk 12 is detected by setting the reproducing speed at maximum. Therefore, it is possible to detect the maximum level point of data recorded on the disk 12 accurately and rapidly, and to facilitate, for example, the setting work of a recording level. In such a way, it is possible to offer the convenience on the operation to the user.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a disc playback device capable of switching the playback speed, and in particular to a disc playback device that can accurately and quickly determine the maximum level point of data recorded on a disc. It relates to things that can be detected.

(Prior Art) As is well known, in a disc playback device such as a compact disc player, the recording time is determined in consideration of recording the played analog audio signal on another recording medium such as a tape. In order to shorten the standard 2
Some devices are now appearing that have a function that allows them to play back at twice the speed.

However, this type of disc playback device is still in the development stage, and it is difficult to perform optimal playback operations when playing at standard speed and when playing at twice the standard speed. Also, the standard 2
There is still a lot of room for improvement in terms of configuration and performance, such as actively utilizing the double speed playback function to make handling easier.

(Problems to be Solved by the Invention) As described above, conventional disc playback devices equipped with the function of playing at twice the standard speed are still not able to fully meet the needs of users. The problem is that it is not.

Therefore, this invention was made in consideration of the above circumstances, and by detecting the maximum level point of the playback signal read from the disk at the highest playback speed, the maximum level point of the data recorded on the disk can be detected. It is an object of the present invention to provide an extremely good disc playback device that can detect accurately and quickly, facilitates the work of setting the recording level, etc., and is convenient for the user to handle.

[Structure of the Invention] (Means for Solving the Problems) That is, the disc playback device according to the present invention is intended for a device in which the playback speed can be changed by changing the rotational speed of the disc, and the playback speed can be set to the highest speed. This device is configured to detect the maximum level point of the reproduced signal read from the disk at high speed.

(Function) According to the above configuration, the maximum level point of the playback signal read from the disk is detected at the highest playback speed, so the maximum level point of the data recorded on the disk can be accurately and accurately detected. It can be detected quickly, making it easier to set the recording level, for example, and making handling convenient for the user.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 11 denotes a disk reproducing structure section, which includes a disk table 14 on which a disk 12 is placed and rotated by the action of a disk motor 13, and a disk table 14 on which a disk 12 is placed.
an optical pickup 15 that reads digital data recorded on the disk 2; and a pickup feed motor 1 that moves the optical pickup 15 in the radial direction of the disk 12.
It consists of 6.

Then, the reproduction R output from the optical pickup 15
The F signal is sent to the current-voltage conversion amplifier circuit 17. ia, an analog amplifier circuit 2 consisting of a wideband RF amplifier circuit 19 and an @return circuit 20 that determines the characteristics of the wideband RF amplifier circuit 19;
1 and then supplied to the servo control circuit 22.

This servo control circuit 22 receives input reproduction R.
The F signal is level-sliced at a predetermined slice level and converted into digital data, and a disk motor control signal and a pickup feed motor control signal are generated based on this digital data.

Of these, the disk motor control signal is supplied to the disk motor 13 via a drive circuit 25 consisting of an amplifier circuit 23 and a feedback circuit 24, so that its rotational speed is controlled. Further, the pickup feed motor control signal is supplied to the pickup feed motor 16 via the drive circuit 26, and the optical pickup 1
The movement speed of 5 is controlled.

Note that within the analog amplifier circuit 21, a tracking error signal and a focus error signal are generated. Of these, the tracking error signal is supplied to the optical pickup 15 via a drive circuit 29 consisting of an amplifier circuit 21 and a feedback circuit 28, and tracking servo is performed for an objective lens (not shown). Further, the focus error signal is supplied to the optical pickup 15 via a drive circuit 32 consisting of an amplifier circuit 30 and a feedback circuit 31, and focus servo for the objective lens is performed.

Here, the servo control circuit 22 uses a phase locked loop circuit (PLL) based on the generated digital data.
) 33 to generate a bit synchronization clock.

Then, the servo control circuit 22 generates a data extraction clock based on the bit synchronization clock and outputs it to the digital signal processing circuit 34 together with the digital data.

This digital signal processing circuit 34 operates on a RAM (read only memory) 3 in synchronization with a system clock that is inputted from a clock generation circuit 36 having a crystal oscillator 35.
7 is used to absorb jitter components, correct errors, and perform correction processing on digital data. and,
The digital data output from this digital signal processing circuit 34 is transferred to the D/A (digital/analog) conversion circuit 3.
8, which is converted into an R channel analog signal and supplied to an audio reproduction system (not shown) via amplifier circuits 39 and 40 and output terminals 41 and 42, respectively.

Here, this compact disc player has:
A reproduction speed control circuit 43 is provided.

When the disc 12 is required to be played back at double the standard playback speed, the playback speed control circuit 43 controls the crystal excavator 35 and the phase-locked loop circuit 33 to operate at twice the frequency of the aS. υJtllll to generate clock and bit synchronization clocks, and wideband RF amplification circuits 19 . This functions to switch the characteristics of the drive circuits 25, 29, and 32 so that they are optimal for reproduction at twice the standard speed.

The playback speed control circuit 43 also has the function of causing the display circuit 44 to display the operating status, time, etc. of the compact disc player.

Here, the system clock output from the clock generation circuit 36 is supplied to the cassette tape recorder 46 via the digital signal processing circuit 34 and the synchronization control circuit 45. This cassette tape recorder 46 is of a type in which the tape running speed during recording and reproduction changes in synchronization with the system clock, that is, the recording and reproduction speed changes.

Therefore, when the disc 12 is being played back at the standard speed, the system clock is also at the standard frequency, so when the cassette tape recorder 46 is set to the recording state, the recording speed is also standard, and the output terminals 41 and 42 The output acoustic signal is now recorded on the tape at standard speed. Furthermore, when the disc 12 is being played back at twice the standard speed, the system clock is also at twice the standard frequency, so if the cassette tape recorder 46 is set to recording mode, the recording speed will also be twice the standard speed. Therefore, output terminal 4
The sound signal output from 1°42 is recorded on the tape at twice the standard speed.

In the above configuration, the features of the present invention will be explained below with reference to the flowchart shown in FIG. First, when the start (step S1) is started, the playback speed control circuit 43 is set to a mode in which playback is performed at twice the standard speed (hereinafter referred to as double speed mode) in step S2, and then, in step S3, a comparison is made. The level is set to the initial value.

Next, in step S4, it is determined whether the optical pickup 15 is located at the end of the disc 12.

If it is not located at the end (No>), the disc 12 is played back at twice the standard speed, and step $5
Then, the comparison level and the reproduced signal level Ld read by the optical pickup 15 are compared in magnitude.

Here, if the comparison level ≦ the reproduced signal level ld, then (
After setting the detection flag in the playback speed control circuit 43 in step S6 (YES), it is determined in step S7 whether one second has elapsed.

Further, in step S5, comparison level≦reproduction signal level l
If it is not -d (No), the process directly proceeds to step S7.

Then, in step S7, if one second has not elapsed (No>), the process returns to step S4, and if one second has elapsed (YES), in step S8, it is determined whether the detection flag is set or not. That is, the comparison level and the reproduced signal level ld are compared in magnitude every second.

Here, if the detection flag is set in step S8 (YES), the detection flag is cleared in step S9, and in step 810, the disc latched in the register provided in the playback speed control circuit 43 is Address data A, which will be described later, indicating a position on the playback speed control circuit 43 is set in a memory provided in the playback speed control circuit 43.

Next, in step S11't', the optical pickup 1
After the address data B of the current position of No. 5 is set in the memory, it is determined in step 812 whether or not the comparison level is OdB. And if it is not OdB (No),
In state S13, the comparison level is increased by one step, and in step S14, the address data of the current position is set in the register, and then the process returns to step S4.

Further, if the detection flag is not set in step S8 (No), the process directly proceeds to step 814.

If the comparison level is OdB in step 812 (YES), then in step S15, the playback speed control circuit 4
3 is set to standard speed mode. Then step 8
At step 16, the address data A and B set in the memory are repeatedly played back at the standard speed, and the process ends (step 517).
) to be done.

Here, at the time and point of step 316, the area between the address data A and B set in the memory corresponds to the portion of the data recorded on the disk 12 where the reproduced signal level is maximum. This part will be played repeatedly.

According to the configuration of the above embodiment, while the disc 12 is being played back in the double speed mode, the maximum level point of the playback signal read from the disc 12 is detected and that portion is repeatedly played back. The maximum level point of the data recorded on the cassette tape recorder 46 can be easily detected during repeated playback. This makes handling convenient.

Regarding this point, conventionally, when recording from a compact disc player to a cassette tape recorder, due to variations in the recording level depending on the disc and the wide dynamic range, if you set the recording level too easily and start recording, it may suddenly become too loud. There were cases where the sound was recorded with distorted sound, so the recording level had to be set with great care.

Also, with discs other than those you are familiar with, you may not know where the maximum level point is, so play the -degree disc to the end, find the maximum level point with a level meter, etc., search for that part, and play it again. Therefore, it is necessary to set the recording level, which is inconvenient for the user.

By the way, in the past, it was considered to automatically detect the maximum level point by playing back every few tracks on the disc, but the maximum level point may exist on skipped tracks, that is, on tracks that were not played. , which has the WR problem of not being able to perform accurate detection.

However, in the above embodiment, the disk 12 is
Since the maximum level point is detected by reproducing all of the signals, the detection operation can be performed accurately and quickly.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] Therefore, as detailed above, according to the present invention, the maximum level point of data recorded on a disk can be detected accurately and quickly, and the work of setting the recording level, etc., for example, can be facilitated, and the user can It is possible to provide an extremely good disc playback device that can be conveniently handled.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing an embodiment of a disc reproducing apparatus according to the present invention, and FIG. 2 is a flowchart for explaining the operation of the embodiment. 11... Disk playback mechanism section, 12... Disk,
13... Disc motor, 14... Disc table, 15... Optical pickup, 16... Pickup feed motor, 17.18... Current-voltage conversion amplifier circuit, 19... Broadband RF amplification Circuit, 20... Feedback circuit, 21... Analog amplifier circuit, 22... Servo control circuit, 23... Amplifier circuit, 24...
Feedback circuit, 25.26 drive circuit, 27... amplifier circuit,
28...Feedback circuit, 29...Drive circuit, 30...
Amplifying circuit, 31... Feedback circuit, 32... Drive circuit,
33... Phase locked loop circuit, 34... Digital signal processing circuit, 35... Crystal generator, 36... Clock generation circuit, 31... RAM. 38...D/A conversion circuit, 39.40...amplifier circuit, 41.42...output terminal, 43...playback speed II
JI! 11 circuits: 44...display circuit, 45...synchronous control circuit', 46...cassette tape recorder. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In a disc playback device capable of changing the playback speed by changing the rotational speed of the disc, the disc playback device is provided with a detection means for setting the playback speed to the highest speed and detecting the maximum level point of the playback signal read from the disc. A distinctive disc playback device.