US 5,970,031 AGranted

Compact disc player system with vibration-immune interrupted playback capability

AssigneeUnited Microelectronics Corp.

InventorsWei-Hung Huang, Ho-Chi Kwong

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Abstract

A CD player system with vibration-immune uninterrupted playback capability is provided, which can keep the playback of the audio or video from an optical disc to be uninterrupted even if in the event of external vibrations causing an interrupt to the data reading operation on the optical disc due to defocusing and mistracking of the laser pickup head of the CD player system. The CD player system has a laser pickup head for reading data from an optical disc; servo circuit for controlling said laser pickup head; data processor for decoding the data from said laser pickup head; memory circuit for temporary storage of the output data from said data processor; microcontroller for controlling operations of said servo circuit and said data processor; audio reproduction components for reproducing the output data from said data processing means. Further, the data processor includes a RAM & time controller coupled to said memory unit and said microcontroller. In the event of the occurrence of a defocusing or mistracking condition to said laser pickup head, said servo circuit informs said microcontroller of such a condition, causing said mirocontroller to fetch information about which data frame is being currently written into said memory unit and then command said memory unit to discard the data frame and also command said servo circuit to resume the data reading operation by positioning the laser pickup head at the data frame that precedes the discarded data frame.

Claims10

Dependent claims

A CD player system with vibration-immune uninterrupted playback capability, which comprises:

laser pickup head for reading data from an optical disc that is an audio CD containing audio data thereon;
servo means for controlling said laser pickup head;
data processing means for decoding the data from said laser pickup head into playable form;
memory means for temporary storage of the output data from said data processing means;
control means, coupled to said servo means and said data processing means, for controlling operations of said servo means and said data processing means;
and
reproduction means, coupled to said data processing means, for reproducing the output data from said data processing means;
wherein
said data processing means includes:
a RAM & time controller coupled to said memory means and said control means;
an EFM decoder from performing an EFM decoding process on the data read from said optical disc;
a CIRC decoder, coupled to said RAM & time controller, for performing a CIRC decoding process on the output data from said EFM decoder;
an address generator, coupled to said RAM & time controller, for generating an address signal to said memory means;
and
output means, under control by said RAM & time controller, for outputting data from said memory means to said reproduction means;
wherein in the event of the occurrence of a defocusing or mistracking condition to said laser pickup head, said servo means informing said control means of such a condition, causing said control means to fetch information about which data frame is being currently written into said memory means and then command said memory means to discard the data frame and also command said servo means to resume the data reading operation by positioning said laser pickup head at the data frame that precedes the discarded data frame, and
wherein in the event of the occurrence of a defocusing or mistracking condition to said laser pickup head, said control means performs the steps of:
disabling said EFM encoder;
resetting said CIRC decoder;
fetching the information about which data frame is currently being written into said memory means;
commanding said servo means to resume the data reading operation by positioning the laser pickup head at the previous one of the data frame;
and enabling said EFM decoder to restart the EFM decoding process when the next subcode appears.

19 more elements

A method for use on a CD player system of the type having a laser pickup head for reading data from an optical disc that is an audio CD containing audio data thereon, servo means for controlling said laser pickup head;

data processing means for decoding the data from said laser pickup head into playable form;
memory means for temporary storage of the output data from said data processing means;
control means, coupled to said servo means and said data processing means, for controlling operations of said servo means and said data processing means;
and reproduction means, coupled to said data processing means, for reproducing the output data from said data processing means;
wherein the data processing means includes:
an EFM decoder for performing an EFM decoding process on the data read from the optical disc;
a CIRC decoder, coupled to a RAM & time controller, for performing a CIRC decoding process on the output data from said EFM decoder;
an address generator, coupled to said RAM & time controller, for generating an address signal to said memory means;
and
output means, under control by said RAM & time controller, for outputting data from said memory means to said reproduction means;
said method comprising the steps of:
in the event of the occurrence of a defocusing or mistracking condition to said laser pickup head, activating said servo means to inform said control means of such a condition;
activating said control means to fetch the information about which data frame is currently being written into said memory means;
activating said control means to discard the current data frame;
activating said control means to command said servo means to resume the data reading operation by positioning the laser pickup head at the previous one of the data frame;
and
restarting the data reading operation on the optical disc,
wherein in the event of the occurrence of a defocusing or mistracking condition to said laser pickup head, said control means performs the steps of:
disabling said EFM encoder;
resetting said CIRC decoder;
fetching the information about which data frame is currently being written into said memory means;
commanding said servo means to resume the data reading operation by positioning the laser pickup head at the previous one of the data frame;
and enabling said EFM decoder to restart the EFM decoding process when the next subcode appears.

20 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/970,095Filed 13 Nov 1997
Priority: TW 8611377723 Sep 1997
Granted: 19 Oct 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G11B 7/0946
With provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record…
G11B 20/10527
Digital recording or reproducing: audio or video recording; Data buffering arrangements
G11B 2020/10824
Data buffering arrangements, e.g. recording or playback buffers: the buffer being used to prevent vibrations or shocks from causing delays
G11B
Information storage based on relative movement between record carrier and transducer