Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2000-03-22
2004-05-18
Baker, Stephen M. (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
Reexamination Certificate
active
06738944
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital data recording and reproducing apparatus which performs digital encoding compression on various information and records and reproduces the encoding compressed data on and from a non-volatile semiconductor memory card, and more particularly, to a digital data recording and reproducing apparatus which records information data such as a moving image or sound which progresses in a time series manner, on a non-volatile memory card together with error correcting data for the information data, and performs suitable reproduction on information data uncorrectable even with the recorded error correcting data.
2. Description of the Related Art
In recent years, the recording capacities of non-volatile semiconductor memories have been increasing and the recordable amount of data per non-volatile semiconductor memory has been increasing. Non-volatile semiconductor memories having card-like shapes have been developed, and digital still cameras for recording still images and audio recording equipment which use such cards in place of silver-halide film or audio recording magnetic tape have been developed and put into practice.
This type of digital still camera and audio recording equipment converts an analog signal picked up and generated by a photographic camera or a microphone into a digital signal, performs encoding compression on the digital signal to convert the digital signal into data having a predetermined data format, and records the data on the non-volatile semiconductor memory. The non-volatile semiconductor memory has a data storage area divided into plural physical blocks each of which stores a predetermined amount of data, and is capable of managing recording or erasure of data for each of the physical blocks. In general, in order to enable recorded data to be read and edited on computer equipment, the non-volatile semiconductor memory adopts a data format conforming to MS-DOS which is an OS for computer equipment.
A microprocessor converts the encoding compressed recorded data into the data format of MS-DOS and creates management file data relative to the recorded data, and records the corrected encoding compressed recorded data and the management file data on physical blocks of the non-volatile semiconductor memory. Thus, reading and erasure of the recorded data recorded on plural physical blocks are performed by using the management file data.
A specific example of a digital data recording and reproducing apparatus using the non-volatile semiconductor memory will be described below with reference to FIG.
5
.
FIG. 5
is a block diagram showing the construction of an audio digital data recording and reproducing apparatus.
An audio input circuit
21
of the audio digital data recording and reproducing apparatus
20
shown in
FIG. 5
is made of a microphone (not shown) which picks up sound such as music or human voice and generates an analog electrical signal, and an amplifier circuit (not shown) which amplifies the analog audio signal generated by the microphone.
During recording, the analog audio signal generated by the audio input circuit
21
is converted to a digital audio signal by an analog/digital conversion circuit (hereinafter referred to as the A/D circuit)
22
, and the digital audio signal is supplied to an encoding compression circuit
23
. The encoding compression circuit
23
performs encoding compression on the digital audio signal, thereby generating predetermined digital compressed data. The encoding compression in the encoding compression circuit
23
uses the compression technique of G729A which is an ITU (the International Telecommunications Union) standard. The digital encoding compressed data generated by the encoding compression circuit
23
is recorded on a card provided with a non-volatile semiconductor memory (hereinafter referred to as the non-volatile memory card)
25
, via a control means
24
composed of a microprocessor (MPU). As is well known, the microprocessor is also called CPU, and is made of one chip on which are integrated various units such as an arithmetic unit which performs arithmetic and logic operations, a control unit which performs interpretations of instructions and generation of control signals, and a storage unit. The control means
24
exerts control on writing and reading of the digital encoding compressed data to and from the non-volatile memory card
25
, and also generates management data on the written digital encoding compressed data.
During reproduction, the digital encoding compressed data read from the non-volatile memory card
25
under the control of the control means
24
is expanded and decoded by a decoding expansion circuit
26
, whereby the digital encoding compressed data is converted to a digital audio signal. The digital audio signal generated by the decoding expansion circuit
26
is converted to an analog audio signal by a digital/analog conversion circuit (hereinafter referred to as the D/A circuit)
27
, and the analog audio signal is supplied to an audio output circuit
28
which serves as an output end made of an amplifier circuit and a speaker (none of which is shown).
An operating switch
29
and a liquid crystal display
30
are connected to the control means
24
. The operating switch
29
serves as an operation input meanswhich has a switch for entering an operation input, such as audio recording, audio reproduction or power-off, into the audio digital data recording and reproducing apparatus
20
. The liquid crystal display
30
displays the operating state of the audio digital data recording and reproducing apparatus
20
according to the input from the operating switch
29
.
Incidentally, the non-volatile memory card
25
is capable of being removably fitted into a card slot provided in the body (not shown) of the audio digital data recording and reproducing apparatus
20
.
The A/D circuit
22
, the encoding compression circuit
23
, the decoding expansion circuit
26
and the D/A circuit
27
are formed as a one-chip audio processing integrated circuit (hereinafter referred to as the audio processing IC).
If the non-volatile memory
25
used in the audio digital data recording and reproducing apparatus
20
has a recording capacity of, for example, 8 Mbytes, the data recording area of the non-volatile memory
25
is managed in the state of being divided into 1,024 physical blocks (8 Kbytes per physical block) as shown in FIG.
6
A. Each of the physical blocks is managed in the state of being divided into plural pages (page
0
to page end) (in the case of 8 Mbytes, one physical block is divided into sixteen pages 0 to 15).
As shown in
FIG. 6A
, each of the pages of the physical blocks of the non-volatile memory card
25
has a data area of 512 bytes and a redundant part of 16 bytes. As shown in
FIG. 6B
, the data area includes a data area
1
made of 256 bytes
0
to
255
and a data area
2
made of 256 bytes
256
to
511
. As shown in
FIG. 6C
, the 16 bytes of the redundant part include bytes
512
to
515
assigned to a reserve area, byte
516
assigned to a data status area, byte
517
assigned to a block status area, bytes
518
to
519
assigned to a block address area
1
, bytes
520
to
522
assigned to an error correcting data area (hereinafter referred to as ECC area)
2
, bytes
523
to
524
assigned to a block address area
2
, and bytes
525
to
527
assigned to an ECC area
1
. The data area
1
and the data area
2
correspond to the ECC area
1
and the ECC area
2
, respectively.
When the audio digital data recording and reproducing apparatus
20
is to record digital encoding compressed data on the non-volatile memory card
25
having such data recording areas, an analog audio signal inputted from the audio input circuit
21
is encoding-compressed and converted into digital encoding compressed data by the audio processing IC
31
, and the control means
24
executes control so that the digital encoding compressed data is recorded on the data area of each page of physical
Baker Stephen M.
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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