JPS6222277A - Disc reproducing device - Google Patents

Abstract

PURPOSE:To attain an easy-to-see demodulated screen of graphic picture data by masking code data corresponding to the graphic picture data among sub-code data outputted externally when the state is set to a state other than the normal reproducing state to output the result. CONSTITUTION:The sub-code data obtained by coding control data, prescribed display data and graphic picture data is recorded on a digital audio disc together with main information data. A signal read by a pickup 15 is fed to an EFM demodulation sub-code extraction circuit 19. When the mode is set to a state other than the normal reproducing mode, a signal SPLAY outputted from a system control 29 goes to an L level. Thus, the code data corresponding to the graphic picture data among the sub-code outputted from the circuit 19 is masked by a AND gate buffer 32 and the result is fed to a sub-code demodulator 36 as zero data. Thus, when the graphic picture data is demodu lated, a displeasant screen is prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a disc playback device that plays back, for example, a CD (compact disc) type DAD (digital audio disc), and in particular, the present invention relates to a disc playback device that plays back a DAD (digital audio disc) of the CD (compact disc) format, and in particular, The present invention relates to improvements in subcode data transmission means for extracting subcode data and transmitting it to a subcode data demodulator.

[Technical Background of the Invention and Its Problems] As is well known, for example, an optical digital audio disc called the CD format contains digital audio data as well as P, Q, R, S, T, U, V, and W. Named 8-bit subcode data is recorded. Of these, data P is provided for determining between songs and during a song, and "1" indicates between songs, and "0" indicates during a song. Data Q is provided as a control signal and represents the number of music channels, presence or absence of emphasis, absolute time, song number, index number within the song, elapsed time of the song, etc. The remaining 8-bit data R-W is currently being considered for use in transmitting color graphics image data.

A playback device (hereinafter referred to as a CD playback device) that plays back digital audio data from the disc includes a subcode data demodulation circuit that demodulates the subcode data, and among the subcode data extracted here, P and Q is used as control data and display data for the reproducing device, respectively, and other data R-W is transmitted together with P and Q to a subcode data demodulation device externally connected to this device. This external subcode data demodulator demodulates the transmitted subcode data and converts it into a color CR.
288 pixels (horizontal) x 192 on the T display screen
This is for displaying the song number, elapsed time between songs, intervals between songs, songs, etc. along with a pixel (vertical) color graphics image. FIG. 3 shows a system configuration in which subcode data is extracted from digital audio data, color graphics image data is demodulated from this subcode data, and a color graphics image is displayed.

That is, in FIG. 3, reference numeral 11 indicates a digital audio disc. This disk 11 has a fourth
The digital data in which one frame consists of 8-bit subcode data, 192-bit digital audio data, and 64-bit error correction (parity) data shown in Figure (a) is formatted as shown in Figure (b). E
It is FM (8 bit/14 bit conversion) modulated and recorded.

Further, reference numeral 12 in the figure is a CD reproducing device, and a disc 11 set in this CD reproducing device 12 is moved by a disc motor 1.
Rotated by 3. This disk motor 13 is controlled to have a constant linear velocity by a disk motor servo circuit 14. An optical pickup 15 is provided below the disk 11. This pickup 15 is provided with well-known servo control by a focus control (FC) servo circuit 16, a tracking control (TC) servo circuit 17, and a PU feed control circuit 18.
This allows the data signal SRF recorded on the disk 11 to be read out. Data signal SRF read out by this pickup 15
is supplied to the EFM demodulation and subcode extraction circuit 19.

This EFM demodulation and subcode extraction circuit 9 receives the bit clock 5P from the pit clock regeneration PLL circuit 20.
This circuit performs EFM demodulation and subcode extraction of the input data signal SRP based on LCK, and this circuit 19 outputs digital audio data DAUD, serial format 8
Bit subcode data D 5BSO and serial format subcode Q data D 5UBQ are output, and at the same time, a frame synchronization clock signal (7,35kllz) is output.
5WDCK, subcode synchronization signal (1/75 kllz
) S 5UBSYNC is output. The data formats for each one frame and one subcode synchronization signal period of audio data D AUD after EFM demodulation and subcode data D5BSO after extraction are as shown in FIGS. 4(c) and (d), respectively. It has become.

The above-mentioned digital audio data D AID is subjected to error detection and correction processing in the error correction circuit 21, and the L channel and R channel are alternately output as data DO of 16 bits/sample.
It is output to the digital-to-analog (D/A) converter 22 as UT. The analog signal SDA output from this D/A converter 22 is separated into an L channel and an R channel by an L/R multiplexer circuit 22. The two channel signals S DAL and S DAR separated here are converted to the original analog audio signals SΔL, SAI? by low pass filters (LPF) 24 and 25. is restored and output to an audio playback device (not shown) via the output terminal 2f3.27.

Here, the analog audio signal SAL.

SAR is measured in PLAY (normal playback) mode and CUE (fast forward playback)/REVIE (fast rewind playback) mode (while monitoring the analog output, move pickup 15 to disc 1).
The muting circuit 28 cuts off modes other than the PLAY mode (1) in which the signal is sent in minute steps in the radial direction to search for the desired point of the song.

The subcode Q data D5UBQ and the subcode synchronization signal S5UBSYNC are both supplied to the system control circuit 29. This system control small circuit 29 demodulates the subcode Q in accordance with the subcode synchronization signal S5LIBSYNC, controls the entire CD reproducing apparatus, and displays information on the display 30. In addition, PLAY mode and CU mode can be controlled by operating a keyboard (not shown).
E/RE VI E W mode constant +: Muting control signal S MUTE that controls the muting circuit 28 accordingly (“H” mute on, “L”
” mute off).

8-bit serial format subcode data DSBSO output from the EFM demodulation subcode extraction circuit 19
is supplied to an open collector two-man AND gate buffer 32 together with SMUTE obtained by inverting the muting control signal SMUTE by an inverter gate 31.
The subcode synchronization signal S5UBSYNC and the frame synchronization clock signal SWDCK are supplied to open collector buffers 33 and 34, respectively. Furthermore,” two pairs of C
Each circuit of the D playback device 12 is a system clock generation circuit 3.
The drive is controlled by a control clock generated by 5.

Subcode data D5I3SO, subcode synchronization signal S5tlBSYNC, and frame synchronization clock signal SWDCK output from each buffer 32 to 34 of the CD playback device are all supplied to subcode data demodulation device 3G. The three types of signals manually input to this subcode data demodulator 3G are first pulled up by the power supply voltage +VC2 applied via the resistor circuit 37, and then P-
The signal is supplied to a Q demodulation circuit 38 and an R-W demodulation circuit 39.

Each code data D demodulated by each demodulation circuit 38 and 39
P-Q and D R-W are each supplied to a color graphics processor 40. This color graphics processor 40 receives input data D P-Q, D
This video signal 5VIDEO is generated from R-W with 192 pixels vertically and 288 pixels horizontally.
VIDEO is supplied to a color CRT display 42.

Here, the subcode data demodulator 36 generates a read clock SEXCK, and this read clock SEXCK.
EXCK via open collector buffer 41
"The CK signal is added to the CK terminal of the EFM demodulation subcode extraction circuit 19 of the CD playback device 12.
The terminal is supplied with the power supply voltage +VC through the fixed resistor R1.
It is pulled up by I. That is, the above EF
When the read clock SEXCK- from the buffer 41 is applied to the M demodulation subcode extraction circuit 19, 8
The bits of subcode data D5BSO are sequentially read out and transmitted to the subcode data demodulation device 3B via the opposite device sofa 32. FIG. 5 shows the transmission timing of the subcode data D5BSO.

In Fig. 5, (a) shows the PLAY mode or CU
Each signal transmission timing in E/REVI EW mode is shown. In this case, the muting control signal S
Since the inverted output SMUTE of MUTE becomes "H", the AND gate buffer 32 becomes enabled. Therefore, the contents of the subcode data D5BSO are updated as 8-bit data by the fall of the frame synchronization clock signal SWDCK. External read clock S
If EXCK- is not input, only subcode data P will be output.

Here, when SEXCK- is input for 7 clocks, the serial format subcode data D5BSO- output from the ant gate buffer 32 is sequentially output from Pn+i to Qn+
i, Rn+i, Sn+i, Tn++
, Un+i.

Vn+i, Wn+i [n, i: Integers. This 'subcode data D5BSO- is sampled by the subcode data demodulator 36 at the timing TSP shown in the figure, and read into the PQ demodulation circuit 38 and the RW demodulation circuit 39.

Further, (b) shows each signal transmission timing when the CD reproducing apparatus is not in the PLAY mode or the CUE/REVI EW mode, for example, in the playback pause (PAUSE) mode. In this case, the inverted output SMUTE of the muting control signal SMUTE becomes "L",
Since the AND gate buffer 32 closes the gate, all bits of subcode data D5BSO- become 0 and P-
The signal is transmitted to the Q demodulation circuit 38 and the R-W demodulation circuit 39.

The subcode data D 5BSO- is demodulated by the PQ demodulation circuit 38 and the R-W demodulation circuit 39 into subcode data D P-Q and D R-W, and the color graphics processor 40 converts the subcode data D 5BSO- into the video signal 5VI.
After being converted to DEO, the color CRT display 42
This color CRT display 42 displays a 288 pixel (horizontal) x 192 pixel (vertical) color graphics image transmitted using the subcode data R-W, and at the same time the subcode Song number (TNO) and elapsed time (M I N, S
E C) is superimposed and displayed in the form TNO:MIN:SEC. At this time, TNO: MIN
:The color of SEC is sequentially switched during and between songs by subcode data P.

To explain the above subcode data R-Q in more detail, one cycle of subcode synchronization signal S5UBSYNC 1υ1
The format of subcode data R-W after demodulation is called PACKET (, packet), and this PACKET is 4PACK as shown in Figure 6(a).
(pack). Then, the 6 bits of R-W [
MSB:R] is called one symbol, and I PAC
KET consists of 96 symbols, I PACK consists of 24
It is made up of symbols. The details of the data structure in IPACK are shown in FIG.

That is, the symbol O indicating a command indicates the use of subcode data R, S, T, U, V, W, and the color CR
For purposes of transmitting data for displaying graphics images on the T display 42, MODE-[R3T code-[001], ITEM-[UVW
] - [001]. Symbol 1 is also used as symbol 2 in an instruction code for controlling a color graphics image on the color CRT display 42.
．． 3.21 to 23 are assigned to parity symbols as ECC (error check code), and symbols 4 to 19 are assigned to data fields corresponding to the instruction codes.

Also, subcode data R, S, T, U, V.

W is not recorded, that is, all 6 bits or “0”
In order to maintain compatibility with discs with ``MODE-[0
00], ITEM-[000ko and "Seromort" which defines all bits of symbols 1 to 23 as "0"
There is. Therefore, the color graph ink probe sensor 40 determines whether the demodulated data in zero mode or the R-W demodulating circuit 39
If the data is output from 1, the data corresponding to 1 P A CK is ignored, and the graphics image on the color CRT display 42 is held in the "zero mode" state before data demodulation.

By the way, in the subcode data transmission means of the conventional disc playback device as described above, the PLAY mode and CUE
The subcode data extracted in the /REVIEW mode is directly transmitted to the subcode demodulator, but in the CUE/REVIEW mode, as shown in FIG. 7(a), the subcode data extracted in the figure is The pickup 15 is intermittently moved in the radial direction of the disk 11 (in the direction of the arrow B in the figure) with respect to the disk 11 rotating in the direction of arrow A, and the output signal SI? of the pickup 15 is read partially. P is an intermittently correct data signal (C, D in the figure) as shown in FIG.

part E). Therefore, when subcode data R-W is demodulated by a subcode demodulation device, correct demodulated data can only be obtained intermittently. In this case, on a color CRT display, for example, as shown in Figure 8(a), the FONT (font) of 6 pixels (horizontal) x 12 pixels (vertical) that constitutes the graphics screen is used as a unit. A graphics pattern that has no correlation with the display screen is displayed at an appropriate position, or the same figure (
As shown in b), there may be an inconvenience in which parts that the creator did not intend are scrolled, resulting in an unsightly screen being displayed.

[Object of the Invention] This invention was made to improve the above-mentioned problems, and subcode data in which control data, predetermined display data, and graphics image data are encoded is recorded together with main information data. Playing the disc, demodulating the main information data in a special playback state, extracting the subcode data, and outputting this subcode data to the outside in response to a read control signal from an externally connected subcode data demodulator. To provide a disc playback device in which the screen does not become unsightly when graphics image data is edited, and does not cause abnormal display when a demodulated image of display data is superimposed on a graphics image. The purpose is to

[Summary of the Invention] That is, the disc playback device according to the present invention plays back a disc on which subcode data, which is coded control data, predetermined display data, and graphics image data, is recorded together with main information data. In the device that demodulates the main information data in a normal reproduction state, extracts the subcode data, and outputs the subcode data to the outside in response to a read control signal from an externally connected subcode data demodulator, When set to a state other than a playback state, code data corresponding to the graphics image data among the subcode data outputted to the outside is masked and outputted to the outside as zero data. be.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to FIGS. 1 and 2. However, in FIG. 1, the same parts as in FIG. 3 are denoted by the same reference numerals, and only the different parts will be described here.

FIG. 1 shows its configuration. In the subcode transmission means of this CD playback device, serial format subcode data D 5BSO and subcode synchronization signal S 5UBSYNC output from the EFM demodulation subcode extraction circuit 19 are transmitted.
, the frame synchronization clock signal SWDCK is output from the open collector two-man AND gate buffer 32, respectively.
, is supplied to the subcode demodulator 36 via the open collector two-power amplifier 33 and 34, and after being pulled up by the power supply voltage +VC2 applied via the resistor circuit 37, the P-Q demodulator circuit 38 and the R-W demodulator It is supplied to circuit 39. Furthermore, by applying the read clock SEXCK- from the subcode demodulation device 36 to the CK terminal of the EFM demodulation subcode extraction circuit 19, 8-bit subcode data D5r3SO or the like is sequentially read out from the EFM demodulation subcode extraction circuit 19. It is now possible to

The gate of the AND gate buffer 32 is controlled by a gate control signal S_GAT[E from a gate control circuit 43. This gate control circuit 43 is composed of a fixed resistor R2, a capacitor C2, a two-way gate G1-04, and D-type flip-flops FFI and FF2. And E.F.M.
The frame synchronization clock signal S WDCK output from the demodulation subcode extraction circuit 19 is connected to a fixed resistor R2, a capacitor CL, and two gates GL and 2 connected to an inverter.
It is differentiated by a differentiating circuit consisting of a human clock gate G2 and converted into a differentiated pulse synchronized with the falling edge of the frame synchronization clock signal SWDCK. The output a of the NOR gate Gl is supplied to the clock input terminal of the flip-flop FFI. The data input terminal of this flip-flop FFI is connected to the P output from the system control circuit 29.
LAY signal S PLAY (“H” in PLAY mode, “L” in other cases) is supplied.

This PLAY signal SP[, AY is a flip-flop FF
Synchronized with the rising edge of the frame synchronization clock signal SWDCK by I, the two-man gate G3 is synchronized with the differential pulse b from the data output terminal Q and the differential pulse b from the gate G2.
supplied to The output C of this two-person gate G3 is D
It is supplied to the preset input PS of the type flip-flop F'F2. The data input terminal of this flip-flop FF2 is fixed at the "L level" (ground level), and the clock input terminal is supplied with a read clock signal inverted by an inverter-connected two-way gate G4.

A gate control signal SGATE for the AND gate buffer 32 is output from the data output terminal Q of the flip-flop FF2. Note that the preset input terminal PS of the flip-flop FF2 is an inverted input.

The operation of the above configuration will be described below with reference to FIG. 2.

FIG. 2(a) shows the operation timing of the subcode transmission means when the CD reproducing apparatus is in the PLAY mode and S PLAY-"H". First, the output a of the NOR gate G1 is the frame synchronization clock signal S W
The falling and rising changes occur in response to the rising and falling of DCK and are delayed by the time constant provided by the fixed resistor R2 and capacitor C1. For this reason, Noah Gate G
The output signal 2 becomes a pulse signal that rises in response to the fall of the clock signal SWDCK and falls in response to the rise of the output a of the NOR gate Gl. This pulse signal is the differential pulse mentioned above.

Here, as shown in FIG. 2(a), the PLAY signal SP
When LAY becomes “H”, the Q of flip-flop FFI
The output becomes “H” at the first rise of the above NOR gate output a.
”, but the output C of Noah gate G3 is Noah gate) G2
It becomes "L" at the first fall of the output signal. Therefore, since the flip-flop FF2 is always forcibly preset, the gate control signal S GATE outputted from its output terminal Q becomes "H". Therefore, from the AND gate buffer 32, the read clock signal SEX
Every time CK" is input to the EFM demodulation subcode extraction circuit 19, all bits of the subcode data D5BSO obtained are directly output in order from data P. At this time, the read clock signal SEXCK is clocked 7 clocks and 1 When transmission for one frame is completed manually within one frame interval (approximately 136 μs), the missubcode data W is retained, but is updated at the fall of the next frame synchronization clock signal SWDCK. , new subcode data P is output.When the read clock signal SEXCK- is further applied, transmission of one frame of subcode data is started in the same manner as described above.

FIG. 2(b) shows the operation timing of the subcode transmission means when the CD playback device is in a mode other than the PLAY mode, for example, in the CUE/REVI EW mode, and the signal goes to S PLAY-“L”. It is. In this case as well, the output a of the NOR gate Gl is the frame synchronization clock signal S.
The NOR gate G2 changes in response to the rise and fall of WDCK and is delayed by the time constant of fixed resistor R2 and capacitor CI.
The output signal becomes a positive pulse that rises in response to the fall of the clock signal SW[)CK and falls in response to the rise of the output a of the NOR gate G1.

This positive polarity pulse b is inverted in polarity by the NOR gate buffer G3, becomes a negative polarity pulse C, and is applied to the preset terminal PS of the D-type flip-flop FF2. Therefore, the flip-flop FF2 is preset every time the frame synchronization clock signal SWl)CK falls.
It is set by the first fall of the read clock signal S excK- input via the NOR gate buffer G4. That is, when the flip-flop FF2 is preset by the negative pulse C, the gate control signal 5G output from the flip-flop FF2
ATE becomes “H” level, and the AND gate buffer 32 receives serial format subcode data D5B transmitted from the EFM demodulation subcode extraction circuit 19.
The SO is directly output to the external subcode data demodulator 36.

Here, after the subcode data demodulator 36 reads the subcode data Q at the sampling point tn,2, the read clock signal SEXCK is inverted from "H" to "L". At this time, read clock signal S
Since the gate control signal S GATE outputted from the flip-flop FF2 becomes "L" due to the fall of EXCK-, the AND gate buffer 32 cuts off the serial format subcode data D5BSO output and instead outputs "0". "It will start outputting data. From now on,
Even if the above read clock signal SEXCK is applied,
The state of flip-flop FF2 does not change unless it is preset. Therefore, subcode data R-W is masked to "0" and transmitted. moreover,
When the flip-flop FF2 is preset in response to the falling edge of the next frame synchronization clock signal SWDCK, the gate control signal SGATE becomes H", so the AND gate buffer 32 outputs the subcode data D5BS.
O will be output directly. At this time, after the updated data P is output, the read clock signal S EXC
Data Q is output at the rising edge of K. Thereafter, as the read clock signal SEXCK falls, the gate control signal SGATIE becomes "L" as described above, so that the data R-W is output masked to "0", and the subcode data demodulator 36 sequentially outputs the data R-W. transmitted to.

Therefore, in a CD playback device configured with the subcode data transmission means as described above, mask processing is performed so that the subcode data demodulation device demodulates all 6 bits of subcode data R-W as "0" in modes other than PLAY mode. and transmit it. For this reason, the R-W demodulation circuit of the subcode data demodulation device outputs demodulated data indicating zero mode, so the color graphics processor stops new control of the color graphics image on the color CRT display. As a result, for example, conventional CUE/R
It is possible to eliminate the unsightly screen that occurred in the EV I EW mode. Furthermore, since the subcode data P and Q are transmitted regardless of the operation mode, as long as the subcode data Q is correctly demodulated by the P-Q demodulation circuit of the subcode data demodulation device, the color graphics image is superimposed. Imposed [TNO]: [
MIN]: [SEC] display is CUE/REV I
Abnormal displays will no longer occur during operation modes such as EW momo-j and pause. Further, in the above transmission means, gate integrated circuits (QUAD 2 INPUT NORGATE) are used as 2' input gate buffers G1 to G4.
Ic), one D type flip-flop FFI, FF2
Since only one dual D-type flip-flop integrated circuit is required, the number of components is extremely small, and it can be realized at low cost.

[Effects of the Invention] As described in detail above, according to the present invention, a disc in which subcode data encoded with control data, predetermined display data, and graphics image data is recorded together with main information data is played back, and a special When demodulating the main information data and extracting the subcode data in the reproduction state, and outputting this subcode data to the outside in response to a read control signal from an externally connected subcode data demodulator, the graphics image data It is possible to provide a disk playback device that does not make the screen look unsightly when demodulating the data, and does not cause abnormal display when superimposing a demodulated image of display data on a graphics image.

[Brief explanation of drawings]

FIG. 1 is a block circuit configuration diagram showing a graphics image display system configured using the disk playback device as an embodiment of the disk playback device according to the present invention, and FIG.
The figure is a timing chart for explaining the operation of the same embodiment, FIG. 3 is a block circuit configuration diagram showing the configuration of a graphics image display system configured using a conventional disc playback device, and FIG. Figure 5 is a timing chart to explain the operation of the system in Figure 3. Figure 6 is a diagram to explain the data format recorded on the disc. Figure 6 is a diagram of the subcode data demodulated by the system in Figure 3. FIGS. 7 and 8 are diagrams for explaining the format, respectively, and are diagrams for explaining problems when subcodes are extracted and demodulated using conventional disc playback devices. 11...Disc ■2...CD playback device, 13...
- Disc motor, 14... Disk motor servo circuit, 15... Optical pickup, 16... Focus servo circuit, 11... Tracking servo circuit,
18...Pickup feed servo circuit, 19...E
FM demodulation subcode extraction circuit, 20... Pit clock recovery PLL circuit, 21... Error correction circuit, 22...
・D/A converter, 23...L/R demultiplexer,
24.25...Low pass filter, 26, 27...
Audio signal output terminal, 28... Muting circuit, 29... System control circuit, 30...
Display device, 31... Inverter gate, 32... AND gate buffer, 35... System clock generation circuit, 36... Subcode data demodulation device, 38...
P-Q demodulation circuit, R-W demodulation circuit, 4o... Color graphics processor, 42... Color CRT display, 43... Gate control circuit, DsBso...
Subcode data, SνDCK...Frame synchronization clock signal, S S, UBSYNC...Subcode synchronization signal, S EXCK...Read clock signal, S G
ATE...Gate control signal.

Claims (1)

[Claims] This device plays back a disc on which subcode data, which is coded control data, predetermined display data, and graphics image data, is recorded together with main information data, and demodulates the main information data in the normal playback state and also demodulates the subcode data. In a disc playback device that extracts subcode data and outputs this subcode data to the outside in response to a read control signal from an externally connected subcode data demodulator, when the disc playback device is set to a state other than the normal playback state, the external output is What is claimed is: 1. A disc reproducing apparatus comprising subcode transmission means for masking code data corresponding to the graphics image data among the subcode data and outputting the masked code data to the outside as zero data.