JPH0253872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for reproducing a rotary recording medium having a spiral information recording track.

In a playback device for a rotating recording medium that has a spiral information recording track and has a pick-up that can move on the rotating recording medium, specify the position on the rotating recording medium where you want to start playback, and after searching for the specified position, select the A compact disk player will be described as an example of such a conventional rotary recording medium, which is configured to be able to start playback from a designated position by giving a playback start command at a certain timing. compact disc (hereinafter referred to as CD)
) has a spiral information recording track, and a time code is recorded as information regarding position.The time code consists of a song number, index number, minutes, seconds, and frame number.

The CD is rotating, the optical pick-up is scanning over the track, and the pick-up can also move in the radial direction of the CD.

FIG. 1 is a block diagram of a CD player.
1 is an optical pickup that takes in information from a CD, 2
is a drive circuit that drives the optical pickup 1 under the control of the microcomputer 5, 3 is a decoder that decodes data from the optical pickup 1, 4 is a digital-to-analog converter that converts the data from the decoder 3 into analog, and 5 is the entire CD player. A microcomputer that controls the
6 is a memory of the microcomputer 5, and 7 is an input/output device for giving commands to the microcomputer 5. FIG. 2 is a flowchart from the start of search to the start of playback on the CD player.

In FIG. 2, t is the time code that the optical pickup 1 sequentially captures, and To is the time code of the designated playback start position. When the search command ``To'' is input from the input/output device 7 and the search begins, the pick-up starts moving and begins searching for To. When the optical pickup 1 takes in To, the search ends and the optical pickup 1 enters a standby state until a playback start command is input. In the standby state, when t=To, the operation of moving optical pickup 1 back one track is repeated.
In other words, the optical pickup 1 traces one round of the track up to the point where To is recorded. When a playback start command is input, the microcomputer 5 compares t and To, and if t≧To, returns the pickup by one track. By doing this, t<T ₀ is guaranteed, but it is not possible to specify at what point on the track for one round the optical pickup 1 is located up to the point where To is recorded. Since playback does not start until t=To, the time it takes for the CD to rotate until the optical pickup takes in To is required from when the playback start command is input until playback starts. The position of the optical pick-up after the playback start command is input depends only on the timing at which the playback start command is input, and depending on that timing, the time it takes for playback to start depends on the time it takes for the CD to complete one rotation. It can be any length within the time required for
In the above method, the playback start is not synchronized with the playback start command, and it has been considered unsuitable for applications that require playback start at accurate timing.

The present invention was developed in view of the above-mentioned drawbacks, and its purpose is not to reproduce the information imported from the pick-up as is, but to temporarily store it in memory.
The object is to enable playback to be started in synchronization with a playback start command.

A feature of the present invention is that, as soon as the search ends, the information captured during optical pickup begins to be written into a memory that can store information for more than one rotation of the rotating recording medium.When the memory becomes full, it enters a standby state and starts playing. It waits for a start command, and when the playback start command is input, it starts outputting the contents stored in the memory one after another and picks up the contents.
The information stored in the memory is moved to the area of the rotating recording medium where it is recorded, and the information on the rotating recording medium after the movement starts to be written in the memory at the same address as when it was previously stored. At this time, start writing from an address that has not been read yet. After the final address of the memory, the program returns to the first address of the memory, and writing and reading are performed at the same speed, and playback continues.

A CD player which is an embodiment of the present invention will be described below. FIG. 3 is a block diagram of this embodiment, and FIG. 4 is a flowchart. In FIG. 3, 11 is a microcomputer that controls the entire CD player, 12 is the main RAM of the microcomputer 11, 13 is a write counter that sequentially increases the write address of the memory 16 using the data strobe 10 as a clock input, and 14 is the data strobe 10. 15 is an address selector that selects one of the write address from the write counter 13 and the read address from the read counter 14 at the timing generated from the data strobe 10; 16; 17 is a digital-to-analog converter; 18 is a decoder that reproduces data from information picked up from a CD; 19 is data from the decoder 18; 10 is data 19 strobe signal, 21 is time code, 22 is CD
23 is a drive circuit that drives the pickup according to instructions from the microcomputer 11. In the fourth step, t is the time code that the optical pickup sequentially captures, To is the time code of the specified playback start position, and T1 is the memory 1
This is the time code at the time when writing to 6 was completed immediately after the search was completed. When the search command "To" is input, the pick-up moves according to a command from the microcomputer 11 and the search begins. Upon detecting t=To, the microcomputer 11 ends the search and starts writing the data 19 into the memory 16. Write to write counter 1
By outputting a clear pulse and an enable signal to 3, the processing is performed sequentially from the first address of the memory to the last address. During writing, the microcomputer 11 monitors t and the write address of the memory 16. The write address of the memory 16 is obtained by the microcomputer 11 counting the data strobes 10. t
When the number of frames, which is the minimum unit of
2. In this case, the address of the memory 12 is determined by the value of t, and the write address of the memory 16 can be referenced by the value of t. The write address is used to connect the data written in the memory 16 and the data 19 taken in by the optical pickup when a playback start command is input later. When writing has been completed to the final address of the memory 16, the microcomputer 11 releases the enable signal of the write counter 13 to complete the writing, and stores t at that point in the memory 12 as T1. Thereafter, it enters a standby state and waits for a playback start command. In the standby state, when t=T1, the operation of moving the pickup back one track is repeated. When a reproduction start command is input, the microcomputer 11 outputs a clear pulse and an enable signal to the read counter 14 immediately or after a certain period of time to start reading the memory 16. The data read from the memory 16 is sent to the digital-to-analog converter 17, and playback starts in synchronization with the playback start command. At the same time as reading from the memory 16 is started, the pickup starts from the CD on which the data stored in the memory 16 is recorded.
In other words, the time code moves to the area between To and T1. This can be achieved by returning the pick-up by one track only when t is greater than or equal to (T1-1 frame). The capacity of the memory 16 is
Even if the pick-up goes back one track, the time code must be between To and (T1-1 frame) and larger than the time code of the part being read, so data for one CD rotation can be stored. It needs to be larger than the capacity. After moving the pickup to the area where the data is stored in the memory 16, the microcomputer 11 waits for the number of frames, which is the minimum unit of time code, to be updated. When the number of frames is updated, data 19 in the new time code sets in the write counter 13 the address of the memory 16 written at the time of writing to the memory 16 immediately after the search. This address can be obtained because the address of the memory 16 where the first data 19 of each time code is stored is stored in the memory 12 so that the time code can be referenced as an index when writing to the memory 16 immediately after the search. Can be done. writing counter 13
The setting is performed by outputting an address and a load pulse. Thereafter, by outputting an enable signal to the write counter 13, the data written immediately after the search and the data 19 fetched from the pickup 22 are concatenated in the memory 16. As a result, new data 19 is written to the write address that precedes the read address, writing and reading are at the same speed based on the data strobe 10, and the next address of the memory 16 after the last address is the first address. , so regeneration is performed constantly.

According to the above-described embodiment of the present invention, even if a playback start command is given at any timing in a standby state after a search is completed, playback can always be started in synchronization with the playback start command.

This embodiment also has the advantage that by operating the read counter 14, the contents of the memory 16 can be reproduced repeatedly. After the search is completed and writing to the memory 16 is completed, the address of the memory 16 where the data at the time code at which you want to start playback and the time code at which playback ends is stored is read from the memory 12, and the time code at which you want to start playback is read out. After outputting the corresponding address along with the load pulse to the read counter 14 and cassetteing it, an enable signal is output and the contents of the memory 16 begin to be reproduced. Microcomputer 1
1 is data strobe 1 at the start of reading.
Start counting 0 and monitor the read address.
When the microcomputer 11 detects that the readout has reached the address corresponding to the end of playback,
The address of the memory 16 corresponding to the time code to start playback is set in the read counter 14, and playback is started again. By continuing this operation, the contents of the memory 16 can be reproduced repeatedly. By changing the address value set in the read counter 14 from the second time onwards, it becomes possible to repeat reproduction by shifting the reproduction range.

FIG. 5 is a block diagram showing another embodiment of the present invention, in which the same parts as in FIG. 3 are designated by the same reference numerals. What differs from FIG. 3 is that the clock input to the read counter 14 is sent from the microcomputer 11, which allows the contents of the memory 16 to be played back at any speed generated by the microcomputer 11. becomes.

According to the present invention, when a playback start command is input, the playback of the information stored in the memory is started in synchronization with the command, and the continuation of the memorized information is picked up from the rotating recording medium and read into the memory to continue playback. , you can start playback from the specified position and continue from there.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional CD player.
Fig. 2 is a flowchart from the start of the search to the start of playback, Fig. 3 is a block diagram showing an embodiment of the CD player of the present invention, Fig. 4 is a flowchart from the start of the search to the start of playback, and Fig. 5 is a flowchart from the start of the search to the start of playback. FIG. 3 is a block diagram of another embodiment. In the figure, 11 is a microcomputer, 12 is a memory, 13 is a write counter, 14 is a read counter, and 16 is a memory.

Claims (1)

[Claims] 1. A device that drives a rotating recording medium on which information is recorded in a spiral, a pick-up that moves and picks up information on the rotating recording medium, a memory that stores the picked-up information, and a device that specifies and specifies the playback start position. and a means for inputting a playback start command after the search, and starts reading out the information stored in the memory in synchronization with the playback start command, and rotates the continuation of the information already stored in the memory. A rotating recording medium playback device characterized by picking up a recording medium, reading it into a memory, and continuing playback.