EP 1021876 A4 20030502 - SIGNAL PROCESSING METHOD AND DEVICE
Title (en)
SIGNAL PROCESSING METHOD AND DEVICE
Title (de)
SIGNAL-VERARBEITUNGS-METHODE UND -VORRICHTUNG
Title (fr)
PROCEDE ET DISPOSITIF DE TRAITEMENT DE SIGNAUX
Publication
Application
Priority
- FI 973919 A 19971009
- US 9817743 W 19980826
Abstract (en)
[origin: WO9920004A1] The invention relates to digital signal processing and specificly to level control of a pulse density modulated (PDM) signal generated by a sigma-delta modulator. A single-bit pulse density modulated PDM signal is generated by a first sigma-delta modulator (2) being an analog modulator, for instance. Level control is performed by multiplying the single-bit pulse density modulated PDM signal by a multibit multiplier (300) to obtain a multibit number stream, which is reconverted into a single-bit PDM signal by a second digital sigma-delta modulator (4). In accordance with the invention, the performance of the second sigma-delta modulator (4) is better than that of the first sigma-delta modulator (2), as to the signal-to-noise ratio. Thus, the most significant factor in the total signal-to-noise ratio (SNR) is the noise level of the first sigma-delta modulator (2), by which the PDM signal was originally generated. In the subsequent second sigma-delta modulator (4), the PDM signal can then be attenuated as much as is the difference between the SNR performances of the modulators without any decrease in the total signal-to-noise ratio. A relative amplification of the PDM signal is provided in this manner.
IPC 1-7
IPC 8 full level
H03M 3/02 (2006.01); H03M 7/36 (2006.01); H04B 14/06 (2006.01); H03M 7/00 (2006.01)
CPC (source: EP KR)
H03M 3/00 (2013.01 - KR); H03M 3/458 (2013.01 - EP); H03M 7/3028 (2013.01 - EP); H03M 7/304 (2013.01 - EP)
Citation (search report)
- [XY] EP 0798865 A2 19971001 - SONY CORP [JP]
- [DY] AZIZ P. M. ET AL: "An overview of sigma-delta converters", IEEE SIGNAL PROCESSING MAGAZINE, vol. 13, no. 1, January 1996 (1996-01-01), pages 61 - 84, XP002230973
- [DY] JOHNS D A ET AL: "DESIGN AND ANALYSIS OF DELTA-SIGMA BASED IIR FILTERS", IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II: ANALOG AND DIGITAL SIGNAL PROCESSING, IEEE INC. NEW YORK, US, vol. 40, no. 4, 1 April 1993 (1993-04-01), pages 233 - 240, XP000384958, ISSN: 1057-7130
- See references of WO 9920004A1
Designated contracting state (EPC)
DE FR GB IT NL
DOCDB simple family (publication)
WO 9920004 A1 19990422; CA 2274637 A1 19990422; CN 1112777 C 20030625; CN 1256037 A 20000607; EP 1021876 A1 20000726; EP 1021876 A4 20030502; FI 103745 B1 19990831; FI 103745 B 19990831; FI 973919 A0 19971009; FI 973919 A 19990410; HK 1025695 A1 20001117; JP 2002510455 A 20020402; KR 20010012348 A 20010215; MY 133001 A 20071031; NO 992777 D0 19990608; NO 992777 L 19990728; TW 408531 B 20001011
DOCDB simple family (application)
US 9817743 W 19980826; CA 2274637 A 19980826; CN 98804731 A 19980826; EP 98942269 A 19980826; FI 973919 A 19971009; HK 00104859 A 20000803; JP 52178599 A 19980826; KR 19997010300 A 19991108; MY PI9804505 A 19981001; NO 992777 A 19990608; TW 87120605 A 19981211