Dynamic information storage or retrieval – Information location or remote operator actuated control
Reexamination Certificate
2000-02-29
2004-08-31
Neyzari, Ali (Department: 2655)
Dynamic information storage or retrieval
Information location or remote operator actuated control
C369S021000
Reexamination Certificate
active
06785195
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of technology for automotive audio systems. More particularly, the invention relates to the idea of allowing both audio data and a control signal for controlling an external device to be sent over a single common line.
Known in the art are automotive audio systems that are installed on automobiles and other vehicles to reproduce the sound recorded on compact disks (CDs) and other media. A typical automotive audio system consists of a main unit that performs various kinds of control such as selection of a sound source and volume control and an external device such as a CD changer which is connected to the main unit via a bus of the type used in computers.
In this configuration, communication for causing information such as a playback command to be transferred between the main unit and the external device is established via the bus to provide better compatibility for an automotive navigation system and a vehicular computer. When the sound from the external device is to be reproduced with a speaker or the like via the main unit in the prior art automotive audio system, the digital audio data read from a recording medium such as a CD in the external device must first be converted to an analog sound signal or the like before it is sent to the main unit.
FIG. 8
is a functional block diagram showing an exemplary configuration of a CD drive for playback of CDs which is an example of the external device in the conventional automotive audio system. In the illustrated case, a replay command sent from the main unit passes through a bus converter unit
10
and an interface unit
30
to be forwarded to a mechanism control CPU
40
. In accordance with the control by the mechanism control CPU
40
, a servo processor
50
controls various servo mechanisms including tracking servo, focus servo and spindle servo via a driver
60
.
A signal read with an optical pickup is amplified with a RF amplifier
70
and fed back to the servo processor
50
. The amplified signal is also sent to a signal processing unit
80
, where it is divided into three
20
components, one of which is sent to a signal converter unit
20
and converted to an analog sound signal, which is then output to an analog audio output line. The other components are used for control purposes and sent to the mechanism control CPU
40
and a decoder
90
.
When reproducing the sound sent from the external device in the system shown in
FIG. 8
, the conventional practice is to send from the main unit a command that requests one or more pieces of music at a time and also send the same command to the mechanism control CPU in the external device. To be more specific, when the sound from the external device need be reproduced, the main unit first makes a music replay command that requests one or more pieces of music at a time and sends it to the bus. Upon reception by the external device, the command is sent to the mechanism control CPU
40
via the bus converter unit
10
and the interface unit
30
. In response to the single command requesting for music replay that has been sent to the mechanism control CPU
40
, one or more pieces of music are reproduced.
In the prior art described above, if a flaw in the medium or some other phenomenon causes an error in the reading of data by the CD driver shown in
FIG. 8
, the error is corrected by the mechanism control CPU
40
and the mechanisms such as servo processor
50
that are controlled by the CPU (the mechanisms are hereunder collectively referred to as “playback means”).
However, the prior art technology described above has had various problems. First, the line of a control signal sent from the main unit to control the external device must be provided as a separate and independent entity from the line of sending a sound signal from the external device to the main unit. This inevitably increases the complexity of the overall system configuration.
Second, the conversion of digital audio data to an analog sound signal in the external device requires dedicated means and processing but this introduces deterioration of sound quality compared to the case of transmitting analog sound signals as such.
Third, the main unit receives the sound signal in analog form and, without analog-to-digital conversion, equalizing and other digital processing steps cannot be performed by means of a digital signal processor (DSP) which means considerable difficulty is involved in processing the sound signal.
Another problem with the prior art is that if, during the playback of at least one piece of music in response to the above-described command in the external device, the main unit performs the operation of jumping to next music (commonly called “track-up”) or getting back to the preceding music (commonly called “track-down”), a command for temporary stop of replay has to be sent from the main unit to the external device. This is simply because in music reproduction, a playback command that is sent from the main unit to the external device requests for one or more pieces of music to be reproduced; after stopping the playback of music by sending the above-described command for playback stop, a command requesting for replay from the desired location must be sent but then the processing scheme becomes complex.
Sending a replay command that requests for reproduction of one or more pieces of music from the main unit to the external device presents a further problem. If an error such as interruption of data occurs in the playback means in the external device due, for example, to a flaw in the medium (i.e., disk) or its vibration, the error is difficult to correct and considerable difficulty is involved in securing the operational stability of the system.
If the error in the reading of data that has occurred due to a flaw in the medium or by some other reason is to be corrected solely by the replay means, it is difficult for the interface unit, the bus converter unit and the main unit to recognize the error information and perform the corresponding necessary operations, potentially causing a problem in the smooth processing by the system.
SUMMARY OF THE INVENTION
The present invention has been accomplished under these circumstances of the prior art and has as an object providing an automotive audio system in which the audio data from an external device is sent to a main unit as it remains in digital form, whereby both audio data and a control signal for controlling the external device are sent over a single common line to simplify the overall system configuration, prevent deterioration of sound quality and facilitating the processing of audio data in the main unit.
Another object of the invention is to provide an automotive audio system in which a command for music replay from the main unit is resolved at equal time intervals in the external device and the resulting small segments of the command are sent to the replay means, thereby increasing the efficiency and stability of the processing in the system.
Yet another object of the invention is to provide an automotive audio system in which an error in the reading of data is corrected in a bus converter unit, whereby the occurrence of the error and the contents of its correction can be recognized in the bus converter unit and the main unit so as to facilitate diverse error correction and stable system operation.
The first object of the invention can be attained by the automotive audio system recited in aspect
1
, which comprises a first unit for acquiring a sound signal to be reproduced, a second unit for controlling the first unit by means of a control signal and also reproducing the supplied sound signal, and a bus for establishing communication between the first unit and the second unit, characterized in that the automotive audio system is adapted to transfer the control signal and the sound signal in digital format between the first unit and the second unit via the bus.
The invention recited in aspect
5
is equivalent to the invention of aspect
1
, provided that it is expressed as a method
Hamashima Sadafumi
Kanazawa Satoru
Clarion Co. Ltd.
McGinn & Gibb PLLC
Neyzari Ali
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