JP2854446B2 - How to play digital car audio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reproducing digital car audio, and more particularly, to a method of temporarily storing audio data read from a recording medium in a DRAM in an in-vehicle mini disk system or an in-vehicle DCC (digital compact cassette) system. The present invention relates to a digital car audio reproducing method in which the digital car audio is read out from the DRAM after being held and outputted as audio.

[0002]

2. Description of the Related Art Compact discs (CDs), which are the mainstream of current music sources, have a number of excellent features not found in conventional records and cassette tapes, such as high sound quality, easy cueing, and high durability. have. However,
With its widespread use, problems such as difficulty in handling due to its 12 cm diameter have also emerged. In view of this, in recent years mini-sizes have been reduced to about half the size (6.4 cm in diameter) of compact discs. A disc (MD) has been proposed.

[0003] Since the minidisk is small and is used while housed in a cartridge, it is possible to obtain excellent portability and handleability essential for outdoor applications such as car audio.

FIG. 5 shows a configuration of a conventional in-vehicle mini disk system. 10 is a spindle motor for rotating the mini-disc MD, 11 is an optical pickup for detecting a recording signal of the mini-disc MD, 12 is FM modulation of an RF signal, a focusing error signal, a tracking error signal, and ATIP data from a detection signal of the optical pick-up 11. An RF amplifier for generating a signal and the like, and further performing waveform equalization and binarization on the RF signal; 13, a feed motor for feeding the optical pickup 11 in the disk radial direction;
0, a servo processor for performing various servo controls such as focusing servo, tracking servo, thread servo, and spindle servo with respect to the optical pickup 11 and the feed motor 13; 15, an ATIP decoder for demodulating ATIP (absolute time) data; EFM / CI
The RC decoder performs reading of EFM data from a binarized RF signal, deinterleaving, error correction, and the like to demodulate ATRAC audio compression data.

[0005] Reference numeral 17 denotes a DRAM of 1 Mbit capacity for temporarily storing ATRAC audio compression data, and 18 denotes a DRAM.
Write / read ATRAC audio compressed data to / from the mini disk 17, and even if data reading from the mini disc MD is interrupted when a shock occurs, the
A shock-proof memory controller that enables continuous output of RAC audio compressed data.
An ATRAC decoder 20 converts the ATRAC audio compression data read from the A / D converter into normal audio sample data, and a D / A converter 20 D / A converts the audio sample data and outputs it to the amplifier.

Reference numeral 21 denotes a DC-DC converter for generating a predetermined DC stabilized voltage from the ACC power supply (+ ACC) and supplying power to the system power except for an operation unit and a system controller, which will be described later. Reference numeral 22 denotes a battery power supply (+ B).
DC that generates a predetermined DC stabilizing voltage from the power source and always supplies backup power to the operation unit and system controller
A DC switch, 23 a power switch for turning on / off the power, 24 an operation unit for performing a power on / off operation, a music selection operation, an eject operation, and the like; 25, a system controller having a microcomputer configuration; Control, normal performance control, music selection control, minidisk MD loading control, unloading control, and the like. When a shock occurs, the system controller 25 prohibits the write operation to the shock proof memory controller 18 and, while monitoring the ATIP data, returns the optical pickup 11 to a position immediately before the shock occurs. By permitting the memory controller 18 to perform a write operation, control is performed so that sound output is continuously performed even when a shock occurs.

With the ACC switch 26 closed,
When a power-on operation is performed on the operation unit 24, the system controller 25 closes the power switch 22. And D
After the power supply voltage output from the C-DC converter 21 rises, the system controller 25 gives a servo-on command to the servo processor 14 to start rotation of the mini-disc MD and signal detection by the optical pickup 11. When the servo is stabilized and the EFM / CIRC decoder 16 starts to output the ATRAC audio compression data, the system controller 25 gives a write start command to the shock proof memory controller 18, and the EFM / CIRC
The ATRAC audio compressed data output from the CIRC decoder 16 is temporarily stored in the DRAM 17, and after a certain period of time, a read start command is also given to read out the old ATRAC audio compressed data stored in the DRAM 17.

ATRAC read from DRAM 17
The compressed audio data is converted to audio sample data by the ATRAC decoder 19 and output to the D / A converter 20, where it is converted to an analog audio signal, which is then output to an external amplifier and output as audio. Thus, the performance of the mini-disc MD starts.

When the signal detection by the optical pickup 12 becomes impossible due to a shock during the performance and the output of the ATRAC audio compression data from the EFM / CIRC decoder 16 stops, the system controller 25 stores the ATIP data immediately before the shock occurs. , Outputs a write temporary stop command to the shockproof memory controller 18, causes the servo processor 14 to perform only a read operation, causes the servo processor 14 to perform a search operation, and monitors the ATIP data output from the ATIP decoder 15 immediately before a shock occurs. Search for the playing position, and return to the normal servo when it comes to that position.
The ATRA from the EFM / CIRC decoder 16
When the output of the C sound compression data is restarted, a write restart instruction is given to the shock proof memory controller 18 to restart the writing. As a result, even if signal detection from the minidisc MD becomes impossible due to a shock, audio output can be continued without interruption within a maximum of about 3 seconds.

[0010]

By the way, when the power is turned off to stop the performance during the performance of the mini-disc MD, the system controller 25 operates the power switch 2
3, the output voltage of the DC-DC converter 21 drops. Also, when the driver opens the ACC switch 26 to get off the vehicle during the performance of the mini disc MD, the DC
-The output voltage of the DC converter 21 drops. Then, the operation of each part of the system stops and the performance stops.
Since the power supply to the RAM 17 is also stopped, the stored data is also erased. Next, in order to listen to the performance of the mini-disc MD, the ACC switch 26 is turned on or the operation unit 24 is turned on.
When the ACC switch 26 and the power switch 23 are closed by performing a power-on operation in the above manner, the performance of the mini-disc MD is resumed under the control of the system controller 25 as described above. Was stable, and it took several seconds for the sound output to start.

When an eject operation is performed to replace the mini-disc MD during the performance of the mini-disc MD, the system controller 25 stops the operation of each part of the system, and then cancels the operation of the loading mechanism (not shown). The loading control is performed to eject the mini disc MD. Next, when a new mini-disc MD is inserted, the system controller 24 performs loading control on the loading mechanism to set the mini-disc MD to the reproducing system, and then sets the mini-disc MD in the same manner as when the power is turned on. The performance of the mini-disc MD thus started is started, but also at this time, several seconds are required until the servo operation is stabilized and the sound output starts.

In the case of car tuners and car decks, sound output starts immediately after the power is turned on, so that music can be enjoyed. Or misunderstand. In the car deck, since the sound output starts immediately after the tape replacement, a sense of incongruity also occurs in the silent state after the mini-disc replacement in the mini-disc system.

Accordingly, an object of the present invention is to provide a reproducing method of a digital car audio system capable of outputting sound promptly at the start of performance of a recording medium.

[0014]

SUMMARY OF THE INVENTION According to one aspect of the present invention, an audio data read from a recording medium is temporarily stored in a DRAM, and then the audio data is read from the DRAM to output a sound. Means for continuing power supply to the DRAM even after the power is turned off, and reading the audio data already stored in the DRAM to turn on the audio when the power is turned on. This is achieved by means for starting the output, and then means for performing a normal audio output operation if audio audio data can be read from the recording medium.

According to another aspect of the present invention, audio data read from a recording medium is temporarily stored in a DRAM.
In the digital car audio in which audio data is read out from the DRAM and audio is output after the audio data is stored in the DRAM, a means for continuously storing the audio data in the DRAM even after the recording medium is taken out, Means for reading audio data already stored in the DRAM when the recording medium is inserted, and starting audio output, and then, when it becomes possible to read audio audio data from the recording medium, a normal audio output operation This is achieved by means for performing

[0016]

According to one aspect of the present invention, the supply of power to the DRAM is continued even after the power is turned off, and when the power is turned on, the audio data already stored in the DRAM is stored. To start audio output, and then, when audio data can be read from the recording medium, a normal audio output operation is performed. Thus, the audio data written to the DRAM before the power is turned off is retained even after the power is turned off, and when the power is turned on, a sound is output using the audio data of the DRAM first. The music can be enjoyed immediately after the disappearance, and the sense of incongruity disappears.

According to another aspect of the present invention, the audio data is continuously stored in the DRAM even after the recording medium is taken out. If the audio data already stored in is read out and the audio output is started, and then the audio audio data can be read from the recording medium,
Normal audio output operation is performed. As a result, audio data written to the DRAM before the recording medium is taken out is retained even after the recording medium is taken out, and when a new recording medium is inserted, sound is first output using the audio data of the DRAM. The silence after the recording medium is inserted disappears and the music can be enjoyed immediately, and the sense of discomfort disappears.

[0018]

FIG. 1 is an overall configuration diagram of an in-vehicle mini disk system according to an embodiment of the present invention. The same components as those in FIG. 5 are denoted by the same reference numerals.

Numeral 10 is a spindle motor for rotating the mini-disc MD, 11 is an optical pickup for detecting a recording signal of the mini-disc MD, 12 is an RF signal, focusing error signal, tracking error signal, ATIP data An RF amplifier for generating an FM modulation signal and the like, and further performing waveform equalization and binarization for an RF signal, a feed motor 13 for feeding the optical pickup 11 in a disk radial direction, and a spindle motor 1
0, a servo processor for performing various servo controls such as focusing servo, tracking servo, thread servo, and spindle servo with respect to the optical pickup 11 and the feed motor 13; 15, an ATIP decoder for demodulating ATIP (absolute time) data; EFM / CI
The RC decoder performs reading of EFM data from a binarized RF signal, deinterleaving, error correction, and the like to demodulate ATRAC audio compression data.

17A is a 1 Mbit DRAM which temporarily stores ATRAC audio compression data, and 18A is an AT
It controls the writing / reading of RAC audio compressed data to / from the DRAM 17, and even if the data reading from the mini-disc MD is interrupted when a shock occurs, it takes only 3 seconds to read A
A shock-proof memory controller that enables continuous output of TRAC audio compressed data.
An ATRAC decoder converts the ATRAC audio compressed data read from 7 into normal audio sample data, and a D / A converter 20 D / A converts the audio sample data and outputs it to the amplifier side.

Here, power is always supplied to the DRAM 17A and the shockproof memory controller 18A from a backup power supply to be described later. As a result, data stored immediately before the power is turned off or immediately before the mini-disc MD is removed is retained even after the power is turned off.

Reference numeral 21 denotes a DC-DC for generating a predetermined DC stabilizing voltage from the ACC power supply (+ ACC) and supplying the system power to the DRAM 17A and the shockproof memory controller 18A, and to each unit of the system except for an operation unit and a system controller described later. A converter 22 is a DC-DC converter that generates a predetermined DC stabilized voltage from a battery power supply (+ B) and constantly supplies backup power to the operation unit, the system controller, the DRAM 17A, and the shockproof memory controller 18A. A power switch for turning off; an operation unit for performing power on / off operation, music selection operation, and eject operation;
Is a system controller composed of a microcomputer, which controls normal performance after power-on or after loading the minidisk MD, music selection control according to music selection operation, unloading control of the minidisk MD according to eject operation, and minidisk MD.
And loading control at the time of insertion of the data. Further, when a shock occurs, the system controller 25A prohibits the write operation to the shock proof memory controller 18A, and returns the optical pickup 11 to a position immediately before the shock while monitoring the ATIP data.
After the return is completed, the shock-proof memory controller 18
By permitting the writing operation to A, control is performed so that sound output is continuously performed even when a shock occurs. Further, the system controller 25A performs audio output control based on the data in the DRAM 17A after the power is turned on again or the minidisk MD is replaced.

26 is an ACC switch provided on the vehicle,
27 monitors the ACC power supply voltage, outputs an ACC off detection signal to the system controller 25A when the ACC voltage falls below a certain reference voltage, and outputs an ACC on detection signal when the ACC voltage rises above a certain reference voltage. An ACC on / off detection circuit that outputs to the system controller 25A. The ACC on / off detection circuit 27 operates with a backup power supply in this embodiment, but may operate with an ACC power supply + ACC or a battery power supply + B.

FIGS. 2 and 3 show the system controller 25A.
FIG. 4 is an explanatory diagram of the reproducing operation when the power is turned on / off, and will be described below with reference to these drawings.

It should be noted that the system has previously been set to the ACC switch 2
6 and the power switch 23 are closed to supply power to the respective units, and the playing state of the mini-disc MD is assumed. At this time, the servo processor 14 has previously set the system controller 25A.
The servo is turned on by the optical pickup 1
In step 1, the recording signal of the mini-disc MD is detected, and the RF amplifier 13 creates the RF signal, equalizes the waveform, and binarizes the signal. The binarized RF signal is demodulated by ATFM audio compression data by an EFM / CIRC decoder 16. The shock proof memory controller 18A and the DRAM 17A are always supplied with power from a backup power supply, and the shock proof memory controller 18A converts ATRAC voice compression data into the DRAM 17A in accordance with a write / read command given in advance from the system controller 25A.
Is read while the data is temporarily stored in the memory. DRAM 17A
ATRAC audio compression data read from
The audio data is converted into audio sample data by the C decoder 19, further converted into an analog audio signal by the D / A converter 20, output to the amplifier side, and output as audio.

As shown in FIG. 4A, the mini disc MD
When the ATRAC audio compression data read from the positions A, B,... Is written into the DRAM 17A,
AT of A, B, ... several seconds later from DRAM 17A
The RAC audio compression data is read and output as audio.

Here, when the driver turns off the power using the operation unit 24 to stop the performance of the mini-disc MD (FIG. 2).
Step 101), the system controller 25A
After confirming that the ACC voltage is on from the output of the CC on / off detection circuit 27 (step 102), a write / read stop command is given to the shock proof memory controller 18A, and the ATRAC audio compressed data is sent to the DRAM 17A. Writing and reading are stopped (step 103). Then, power switch 2
3 is opened (step 104). DC-DC converter 2
Since the system power output from 1 is turned off, the performance of the mini-disc MD stops, and the sound output also stops. However,
Since the power is continuously supplied to the DRAM 17A by the backup power supply even after the system power supply is turned off, the ATRAC audio compression data written before the system power supply is turned off is retained. Here, it is assumed that the point after the point C of the mini disc MD is held in the DRAM 17A (FIG. 4).
(See (1)).

Thereafter, when the driver turns on the power using the operation unit 24 (step 105), the system controller 25A outputs AC power from the output of the ACC on / off detection circuit 27.
After confirming that the C power supply is on (step 1
06), the power switch 23 is closed to turn on the system power output from the DC-DC converter 21 (step 107), the servo is turned on by the servo processor 14 (step 108), and the shock proof memory controller 18A is also turned on. A read command is given to read the ATRAC audio compression data from the DRAM 17A (step 109). The ATRAC audio compression data is converted into audio sample data by the ATRAC decoder 19, and is further output to the amplifier converted by the D / A converter 20 into an analog audio signal. Thus, when the power is turned on, the mini disk M
The audio output after the point C of D starts.

When the servo operation is stabilized and the recording signal of the mini-disc MD can be detected and the output of the ATRAC audio compression data from the EFM / CIRC decoder 16 starts (step 110), the system controller 25A sends the shock-proof memory controller 18A To the ATRAC for the DRAM 17A.
Start writing of compressed audio data (step 11)
1). Therefore, if the reproduction of the mini-disc MD starts from the point E, the performance after the point E is performed following the sound output for about 3 seconds after the point C (see FIG. 4 (2)).

As described above, when the power is turned on by the operation unit 24, the AT stored in the DRAM 17A in advance is used.
Since the audio output starts immediately using the RAC audio compression data, the user can enjoy the performance without waiting after the power-on operation, does not feel uncomfortable, and does not mistake the system for a failure.

In contrast to this, when the driver turns off the ACC switch 26 to get off the vehicle during the performance of the mini-disc MD, the ACC on / off detection circuit 27 detects the ACC power supply off and outputs the ACC off detection signal. Is output. The system controller 25A that has received the ACC off detection signal (step 112) confirms that the power switch 23 is on (step 113), and then issues a write / read stop command to the shock proof memory controller 18A. Then, writing and reading of ATRAC audio compression data to and from the DRAM 17A are stopped (step 114). When the ACC switch 26 is turned off, the system power output from the DC-DC converter 21 is turned off.
The audio output also stops. However, since the power is continuously supplied to the DRAM 17A by the backup power supply even after the system power supply is turned off, the ATRAC audio compression data written before the system power supply is turned off is retained. Here, it is assumed that the point after the point C of the mini disc MD is held in the DRAM 17A (see FIG. 4A).

Thereafter, when the driver returning to the vehicle turns on the ACC switch (step 115), an ACC on detection signal is output from the ACC on / off detection circuit 27, and the system power supply output from the DC-DC converter 21 is output. Voltage rises. When the ACC ON detection signal is input (step 115), the system controller 25A
Turns on the servo in the servo processor 14 (step 108), and gives a read command to the shock proof memory controller 18A to read the ATRAC audio compression data from the DRAM 17A (step 109). This ATRAC audio compression data is ATRAC
It is converted to audio sample data by the decoder 19,
Further, the signal is output to an amplifier converted into an analog audio signal by the D / A converter 20. Thus, when the power is turned on, the sound output immediately after the point C of the mini disc MD starts.

When the servo operation is stabilized, the recording signal of the mini-disc MD can be detected, and the output of the ATRAC audio compression data from the EFM / CIRC decoder 16 starts (step 110), the system controller 25A makes the shock-proof memory controller 18A To the ATRAC for the DRAM 17A.
Start writing of compressed audio data (step 11)
1). Therefore, if the reproduction of the mini-disc MD starts from the point E, the performance after the point E is performed following the sound output for about 3 seconds after the point C (see FIG. 4 (2)).

When the ACC switch 26 is turned on in this way, the audio output starts immediately using the ATRAC audio compression data stored in the DRAM 17A in advance. It can be enjoyed, does not cause discomfort, and is not mistaken for a system failure.

During the performance of the mini-disc MD, when the eject operation is performed on the operation unit 24 to replace the mini-disc MD (step 201 in FIG. 3), the system controller 25A controls the servo processor 14 to control the servo. It is turned off (step 202), and a write / read stop command is given to the shock proof memory controller 18A, and the ATR for the DRAM 17A is
The writing and reading of the AC audio compression data are stopped (step 203). Mini disc MD with servo off
Stops, and ATRAC from DRAM 17A
When the reading of the audio compression data stops, the audio output also stops.

Next, the system controller 25A performs unloading control on a loading mechanism (not shown) (step 204), and ejects the mini-disc MD. When the driver removes the mini-disc MD from the system and inserts a new mini-disc MD (step 205), the system controller 25A performs loading control on the loading mechanism (step 20).
6) Set a new mini disc MD in the playback system. After the setting is completed, the system controller 25A causes the servo processor 14 to turn on the servo (step 20).
7) Also, a shock-proof memory controller 18
A is given a read command to A and A
Read the TRAC audio compressed data (step 20)
8). The ATRAC audio compression data is converted into audio sample data by the ATRAC decoder 19, and is further output to the amplifier converted by the D / A converter 20 into an analog audio signal. As a result, the sound output starts immediately after the replacement of the mini-disc MD.

When the servo operation is stabilized and the recording signal of the mini-disc MD can be detected and the output of the ATRAC audio compression data from the EFM / CIRC decoder 16 starts (step 209), the system controller 25A sends the shock-proof memory controller 18A To the ATRAC for the DRAM 17A.
The writing of the audio compression data is started (step 21).
0).

As described above, when the mini disc MD is replaced, the mini disc A is stored in the DRAM 17A in advance.
Since the audio output starts immediately using the TRAC audio compression data, after the exchange is completed, the user can enjoy the performance without waiting time, does not feel uncomfortable, and does not mistake the system for a failure.

Although the above embodiment has been described with reference to an in-vehicle mini disk system as an example, the present invention is not limited to this, and is similarly applied to an in-vehicle DCC (digital compact cassette) system and the like. What is essential is a system that reads audio data from a predetermined recording medium, temporarily stores the data in a DRAM, and then reads the audio data from the DRAM and outputs audio.

[0040]

According to one aspect of the present invention, the power supply to the DRAM is continued even after the power is turned off, and when the power is turned on, the data already stored in the DRAM is already stored. Then, the audio data is read and the audio output is started. After that, when the audio data can be read from the recording medium, the normal audio output operation is performed. Thus, the audio data written to the DRAM before the power is turned off is retained even after the power is turned off, and when the power is turned on, a sound is output using the audio data of the DRAM first. The music can be enjoyed immediately after the disappearance, and the sense of incongruity disappears.

According to another aspect of the present invention, audio data is continuously stored in the DRAM even after the recording medium is taken out, and then, when the recording medium is inserted, the audio data is stored in the DRAM. If the audio data already stored in is read out and the audio output is started, and then the audio audio data can be read from the recording medium,
Normal audio output operation is performed. As a result, audio data written to the DRAM before the recording medium is taken out is retained even after the recording medium is taken out, and when a new recording medium is inserted, the sound is first output using the data in the DRAM. The silence after the medium is inserted disappears and the music can be enjoyed immediately, and the sense of discomfort disappears.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an in-vehicle mini-disc system embodying a reproducing method according to the present invention.

FIG. 2 is a first flowchart showing the operation of the system controller.

FIG. 3 is a second flowchart showing the operation of the system controller.

FIG. 4 is an explanatory diagram showing a reproducing operation when the power is turned on / off.

FIG. 5 is an overall configuration diagram of a conventional in-vehicle mini disk system.

[Explanation of symbols]

 17A DRAM 18A Shockproof Memory Controller 22 DC-DC Converter 23 Power Switch 25A System Controller 26 ACC Switch MD Mini Disk

Claims (2)

(57) [Claims] 1. A digital car audio system in which audio data read from a recording medium is temporarily stored in a DRAM and then audio data is read out from the DRAM and audio is output, the digital car audio being turned off even after the power is turned off. The power supply to the DRAM is continued. Next, when the power is turned on, the audio data already stored in the DRAM is read and the audio output is started, and then the audio audio data can be read from the recording medium. A method of reproducing a digital car audio, wherein a normal audio output operation is performed. 2. A digital car audio system in which audio data read from a recording medium is temporarily stored in a DRAM and then audio data is read out from the DRAM and audio output is performed, even after the recording medium is taken out. Then, the audio data is continuously stored in the DRAM, and when the recording medium is inserted, the audio data already stored in the DRAM is read out and the audio output is started. A digital car audio reproducing method, characterized in that a normal audio output operation is performed when the digital data can be read.