公开(公告)号：EP0129236A3

公开(公告)日：1988-01-07

申请号：EP84106953

申请日：1984-06-18

申请人： HITACHI, LTD.

发明人： Kobayashi, Masaharu Hitachi-Hachimanyama ,  Arai, Takao ,  Noda, Tsutomu

IPC分类号： H04B12/02 ,  G11B05/09 ,  H03K13/01

CPC分类号： G11B20/10527 ,  H03M1/1019 ,  H03M1/504 ,  H04B14/04

摘要： A signal conversion apparatus for use in a PCM signal processing system in which a series of multi-bit digital signals is produced through sampling and quantization of a multi-channel analog signal. The series of multi-bit digital signals (e.q., 109) includes groups of multi-bit digital signals (e.g., 107, 108) being representative of respective analog signal portions (3, 4) constituting the multi-channel analog signal. The apparatus comprises a translating section (e.g., 121) for producing substitutional multi-bit digital signals (122) from at least one (107) of the groups of digitals corresponding to at least one analog signal portion (3), which substitutional digital signals represent amplitudes of the one analog signal portion at sampling points different from those at which the one analog signal was sampled to provide the one group of digital signals The substitutional digital signals are substituted, in the translating section, forthe one group of the digital signals to produce a corresponding group of sampling point- shifted multi-bit digital signals (122) The resulting PCM multi-bit digital signals (109) are acceptable by digital-to-analog conversion processor requiring PCM digital signals generated through sampling at shifted or different sampling points as compared with the above-mentioned series of digital signals

公开(公告)号：EP0129849A3

公开(公告)日：1986-04-09

申请号：EP84107110

申请日：1984-06-20

申请人： HITACHI, LTD.

发明人： Okamoto, Hiroo ,  Kobayashi, Masaharu Hitachi-Hachimanyama ,  Nishimura, Keizo ,  Noguchi, Takaharu ,  Arai, Takao ,  Shibuya, Toshifumi

IPC分类号： G11B05/09

CPC分类号： G11B20/1809

摘要： This invention relates to an error correction upon reproduction of digital signals. The error correction is performed by decoding code words such as cross-interleaved Reed Solomon codes, in which first code blocks are formed by a plurality of information words which are in the first arrangement state and a plurality of first check words which are produced by codes associated with the plurality of information words with a Hamming distance of d,, and second code blocks are formed by a plurality of information words and a plurality of first check words which are in the second arrangement state and which consist of the said plurality of information words and the said plurality of first check words which are respectively included in the different first code blocks, and by a plurality of second check words which are produced by codes associated with the plurality of information words and the plurality of first check words with a Hamming distance of d 2 . At the first decoding stage, at least errors are detected and at the same time the flags indicative of the decoding states are i added with respect to the second code blocks. At the second decoding stage, in accordance with the contents of the flags and on the basis of a combination of p 2 and q selected from their combinations satisfying 2p 2 +q≤d 1 -1, errors are detected and errors of p 2 words are corrected and erasures of q words to which the flags were added are corrected with respect to the first code blocks.

公开(公告)号：EP0118762A3

公开(公告)日：1988-06-08

申请号：EP84101289

申请日：1984-02-08

申请人： HITACHI, LTD.

发明人： Kobayashi, Masaharu Hitachi-Hachimanyama ,  Noguchi, Takaharu ,  Nishimura, Keizo ,  Tanaka, Hiromichi ,  Nishida, Masami ,  Arai, Takao

IPC分类号： H03K13/02

CPC分类号： H04B14/04 ,  H03M1/0631

摘要： A digital-to-analog converter device for PCM signals at different sampling frequencies (f s1 , f s2 . f s3 ) comprises a signal converter (6a) which expands the frequency distance between a PCM signal band and a side band by converting the sampling frequencies associated with the PCM signals to be reproduced into higher fequencies (2f s1 , 2f s2 ; f s3 ') ' With this signal converter, a single low-pass filter (4a) can be simplfied, having a gradual ramp cut-off characteristic for removal of the side band wherein a pass band cut-off frequency and a stop band cut-off frequency can be adapted for low pass filtering of the PCM signals at different sampling frequencies.