Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – For copying
Reissue Patent
2000-02-24
2002-07-30
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
For copying
C369S053210
Reissue Patent
active
RE037808
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a disc reproducing apparatus for reproducing a disc-shaped recording medium.
2. Description of the Related Art
In a reproducing apparatus for a compact disc (CD), which is a disc-shaped recording medium having the audio information recorded thereon, various sorts of indication based on the disc reproducing information are used for enhancing convenience in use.
It has been known to reproduce and display the program number, that is called track number, recorded on a Q-channel subcode as later explained as a mode
1
, or the elapsed time allocated to each track number, as the display information based on the disc reproducing information in a conventional CD reproducing apparatus.
FIG. 1
shows an example of an optical disc, such as CD.
Referring to
FIG. 1
, an optical disc
101
has a center aperture
102
and, looking from the inner rim towards the outer rim of the disc
101
, includes a lead-in area
103
, as a table-of-contents (TOC) area or a program management area, a program area
104
having program data recorded therein, and a program end area or a so-called lead-out area
105
. In an audio reproducing optical disc having the audio information recorded therein, audio data is recorded in the program area
104
, while the total recording time, the total number of recorded programs and the program-based recording time and so forth, are managed by the lead-in area
103
. When the readout of the audio data in the program area
104
by the disc reproducing apparatus has come to a close, and an optical pickup has reached the lead-out area
105
, the disc reproducing apparatus completes the reproducing operation for the optical disc designed for audio reproduction.
FIG. 2
shows an example of the above-described disc reproducing apparatus.
The disc reproducing apparatus reads out the audio data of the optical disc
101
designed for audio reproduction with an optical pickup
102
and processes the audio data with a digital signal processing circuit
116
to generate playback data which is outputted at a digital signal output terminal
125
or at left and right channels of an analog signal output terminal, not shown.
The optical pickup
112
of the disc reproducing apparatus reads out the audio data of the optical disc
101
, that is the so-called RF signals, and sends the signals to an analog waveform shaping circuit
114
, while sending a focusing servo signal to a focusing servo circuit
120
and sending tracking servo signals and thread servo error signals to a tracking servo circuit
121
.
The analog waveform shaping circuit
114
shapes the waveform of the RF signals from the pickup
112
and sends the shaped signals to a synchronization detection circuit
115
and a clock generating circuit
117
. The clock generating circuit
117
generates reproducing clocks for the RF signals based on the RF signals from the analog waveform shaping circuit
114
. The generated reproducing clocks are sent to the synchronization detection circuit
115
, digital signal processing circuit
116
and to a rotation servo circuit
122
. The synchronization detection circuit
115
detects a frame synchronization pattern from the RF signals and sends the signal, from which frame synchronization pattern has been detected, to the digital signal processing circuit
116
. The digital signal processing circuit
116
decodes the RF signals, from which the frame synchronization pattern from the digital signal processing circuit
116
has been detected, based on the reproducing clocks from the clock generating circuit
117
and reference clocks sent from the quartz oscillator
119
, and sends the decoded signals to a subcoding detection circuit
118
, a D/A conversion circuit
123
and to a digital signal output terminal
125
. The D/A conversion circuit
123
converts the digital signals into analog signals which are sent to an audio amplifier
124
. The audio amplifier
124
amplifies the analog audio signal from the D/A conversion circuit
123
and send the amplified signal to the right and left channels of the analog signal output.
The subcoding detection circuit
118
detects data of subcode P and Q channels, as later explained, and sends the data of the respective channels to the tracking and thread servo circuit
121
.
The subcoding detection circuit
118
detects data of the subcode P and Q channels from the digital signal of the digital signal processing circuit
116
and sends the data of the respective channels to a tracking and thread servo circuit
121
.
The focusing servo circuit
120
generates a focusing operation driving signal, based on the focusing error signal from the optical pickup
112
, and sends the focusing operation driving signal to the pickup
112
for controlling the focusing operation of the optical pickup
112
. The rotation servo circuit
122
generates a rotation driving control signal, based on playback clocks from the clock generating circuit
117
and the reference clocks from the quartz oscillator
119
, and sends the rotation driving control signal to the spindle motor
113
for controlling the rotational operation of the spindle motor
112
.
The tracking and thread servo circuit
121
generates tracking control driving signals based on the tracking servo error signals and the thread servo error signals from the pickup
112
and sends the generated tracking control driving signals to the pickup
112
for controlling the tracking operation of the pickup
112
. The tracking and thread servo circuit
121
generates track position control signals based on data from the P and Q channels supplied from the subcoding detection circuit
118
and sends the position control signals to the pickup
112
for controlling the track positions of the pickup
112
for the programming mode.
The data of the subcode and the P and Q channels as described above are now explained.
The signals recorded on the optical disc designed for audio reproduction are sampled with the sampling frequency of 44.1 kHz, with each sample or word being of 16 bits. The 16-bit-per-word sampled data is split into a symbol of upper 8 bits and another symbol of lower 8 bits and error correction coded or scrambled on the symbol basis so that every 24 symbols of the data make up a frame. This corresponds to 12 original samples, that is 6 samples each of the stereo left and stereo right channels.
The signals assembled into one such frame are of such a format in which each frame
135
has a synchronization pattern data area
131
of 24 channel bits, a subcoding area
132
of 14 channel bits, a program data area
133
, a parity data area
134
, another program data area
133
and another parity data area
134
. The program data area
133
is made up of 12 symbols D
1
to D
12
each being of 14 channel bits, while the parity data area
134
is made up of parity data P
1
to P
4
each being of 14 channel bits. The areas or data portions are interconnected by junction areas each being of 3 channel bits. Thus, each frame
135
is made up of a sum total of 588 channel bits of data.
FIG. 4
shows 98 of the above frames
135
collected together and re-arrayed so that the above areas and data portions of each frame will be contiguous to one another in the vertical direction. The set of data shown in
FIG. 4
in its entirety is also termed a frame. However, for distinction from the frame made up of 588 channel bits, the set of data of
FIG. 4
in its entirety, made up of 98 frames, is termed a subcoding frame. This subcoding frame is made up of a frame synchronization pattern portion
136
, a subcoding portion
137
and a data/parity portion
138
. The subcoding frame is equivalent to {fraction (1/75)} second of the usual CD reproducing time.
The subcoding data, inclusive of the P-channel data and the Q-channel data sent from the subcoding detection circuit
118
of
FIG. 12
, is recorded on the subcoding portion
137
of FIG.
4
. The subcoding portion
137
is of a structure such that 98 frames of from frame F
0
to frame F
98
make up one block
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