JPH0339355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a high speed search device for a digital audio disc player.

Background field Digital audio disk (hereinafter referred to as
Conventionally, in order to search for, for example, the fifth song from the current position in a player (referred to as a DAD), the rotational speed of the DAD is increased and the digital signals of the DAD are sequentially read by an optical head.

However, to read with an optical head, DAD
Because there is a limit to the operating speed of the optical system for applying laser light to the target, it usually takes about 20 to 30 seconds, making high-speed searches impossible.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a high-speed search device for a digital audio disk player that can detect a song to be searched on a DAD at high speed and move the optical head to the head position in a short time. It is about providing.

The present invention utilizes the fact that the head position information of the song to be searched for is recorded in the lead-in section of the DAD, and compares and calculates the head position information of the lead-in section with the current position information, and is characterized in that the signal on the DAD is moved based on the calculation result without being picked up.

Then, the optical head is operated (rough search) based on the calculation results as described above, and then
By picking up the DAD signal with the optical head as in the past and using an operation (fine search) to finely adjust the position of the optical head, the optical head can be searched for the beginning of a song in an extremely short time, approximately 5 seconds. can be moved to position.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the high-speed search device according to the present invention uses a RAM as a lead-in information storage means.
1. A plurality of pieces of information, for example, a plurality of songs, are recorded in the form of digital signals in the DAD 2, and information indicating the song number and the start time of each song is recorded in the lead-in section (not shown). There is. Then, when the DAD 2 is set in the player and the power is turned on, information in the lead-in section is read into the lead-in information storage RAM 1 by the optical head 3, and this information is sent to the RF amplifier 4 and the demodulation circuit 5. The signal is shaped, amplified, and demodulated before being input. Therefore, the RAM 1 stores the song number and the starting time information of each song.

The lead-in information stored in the RAM 1 is decoded by the lead-in information decoding means 6. When a signal instructing the song number to be searched is input from the key input device 7 to the data reference section 8 of the CPU, the lead-in information decoding means 6 reads the starting time information corresponding to the song number from the RAM 1. , and output to the data reference section 8. The data reference unit 8 stores the time information from the lead-in information decoding means 6 in a reference table consisting of a read-only memory described below.
The data is converted into a storage format in the ROM 9 and output to the ROM 9.

On the other hand, the digital signal regarding the song currently being read by the optical head 3 is shaped and amplified by the RF amplifier 4, demodulated by the demodulation circuit 5, and input to the current position information decoding means 10. This decoding means 10 decodes the demodulated signal and outputs the current position to the reference table storage ROM 9 as elapsed time information.

The reference table storage ROM 9 contains information indicating the number of pulses for driving the pulse motor 11 that controls the optical head 3, that is, the number of pulses corresponding to the rotation angle of the pulse motor, and time information corresponding to this number of pulses. For example, when the number of pulses is 500, time information indicating 5 minutes is stored in advance. This ROM9
The selector 1 selects the pulse number information corresponding to the elapsed time information from the current position information decoding means 10 and the pulse number information corresponding to the time information indicating the start of the song number to be searched from the lead-in information decoding means 6.
Output to 2. The selector 12 first outputs pulse number information corresponding to the current position to the latch 13, and then outputs pulse number information corresponding to the song to be searched to the latch 14.

The respective pulse number information from latches 13 and 14 is input to a calculator 15. This computing unit 15
subtracts the pulse number information from the latch 14 from the pulse number information from the latch 13, and sends this result to the judgment circuit 1.
6, the determination circuit 16 outputs the absolute value of the difference in the number of pulses to the drive pulse generation circuit 17, and at the same time turns on the forward rotation start command circuit 18 if the difference in the number of pulses is positive, and turns on the forward rotation start command circuit 18, If the difference in the number of pulses is negative, the reverse rotation start command circuit 19 is turned on and a reverse rotation command is output. Based on this command, the forward/reverse inverting circuit 20 rotates the pulse motor 11 forward or reverse by the number of pulses sent from the drive pulse generation circuit 17.

Next, the operation of the high speed search device of the present invention will be explained with reference to FIG.

First, when the power of the player is turned on, the optical head 3 picks up the lead-in information from the DAD 2, and the table of contents, such as the song number and time information indicating the beginning of the song, is stored in the lead-in information storage RAM 1.

Next, when the search operation begins, the main motor and laser power for DAD rotation are turned on, and the muting circuit is turned on. at this point
For example, when the third song is read by the optical head 3, the current position information decoding means 10 stores a reference table.
The elapsed time to the current position is stored in ROM9, for example 47 minutes 30
Time information indicating seconds is input.

Next, when a signal indicating the fifth song is input from the key input device 7, the lead-in information decoding means 6 reads time information corresponding to, for example, 55 minutes and 15 seconds indicating the starting time of the fifth song from the storage RAM 1. , is input to the reference table storage ROM9.

The reference table storage ROM 9 first outputs the number of pulses corresponding to the elapsed time of 47 minutes and 30 seconds to the latch 13, and then outputs the number of pulses corresponding to the elapsed time of 47 minutes and 30 seconds to the latch 14, indicating the start of the fifth song.
The number of pulses corresponding to 55 minutes and 15 seconds is output.

The difference between the number of pulses of the latch 13 and the number of pulses of the latch 14 is calculated by the calculator 15, and this difference in the number of pulses is input to the judgment circuit 16, which judges whether the difference in the number of pulses is positive or negative. .
In this case, since the song to be searched is the fifth song, it is determined to be correct, and the pulse motor 11 rotates in the normal direction by the difference in the number of pulses. Due to this forward rotation, optical head 3 is DAD
After that, the optical head 3 picks up the signal on the DAD and finely adjusts the pulse motor 11 to position the optical head at the beginning position of the 5th track. Bye.

As explained above, according to the device of the present invention,
The rough position of the optical head is calculated using the information on the beginning position of the track to be searched contained in the lead-in section of the disc (DAD), and the optical head is moved forward or backward based on the calculation result (Rough search). ),
After that, the signal on the disk is picked up and the position of the optical head is finely adjusted (Fine search).
Since two search operations are used together, high-speed search operations are possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a high-speed search device according to the present invention, and FIG. 2 is a flowchart illustrating the operation of the device shown in FIG. 1... Lead-in information storage RAM, 2...
DAD, 3... Optical head, 6... Lead-in information decoding means, 9... Reference table storage ROM, 10... Current position information decoding means, 11... Pulse motor, 1
3, 14...Latch, 15... Arithmetic unit, 16...
Judgment circuit.

Claims (1)

[Claims] 1. A storage means for storing a table of contents and starting time information of each table of contents recorded in a lead-in portion of a digital audio disk, and a signal instructing a table of contents to be searched. and lead-in information decoding means for reading starting time information of the table of contents to be searched from the storage means and outputting the time information, and decoding a signal read out from the digital audio disk via the head and demodulated. current position information decoding means for outputting the current position as elapsed time information; a number of pulses for driving a pulse motor for controlling the head and a time corresponding to the number of pulses are stored; a time-pulse number storage means comprising a read-only memory that outputs pulse number information corresponding to each of the time information when the respective time information from the decoding means and the lead-in information decoding means is input; - a calculation means for calculating the difference in the number of pulses based on the respective pulse number information from the pulse number storage means; and a drive pulse creation circuit for creating the pulse motor driving pulse from the calculation result of the calculation means. 1. A high-speed search device for a digital audio disc player, comprising: determining means for instructing the number of pulses to be generated and determining whether the pulse motor is rotating forward or reverse.