Global Patent Index - EP 1021876 A1

EP 1021876 A1 2000-07-26 - 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

EP 1021876 A1 (EN)

Application

EP 98942269 A

Priority

  • FI 973919 A
  • US 9817743 W

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 (main, further and additional classification)

H04B 14/06

IPC 8 full level (invention and additional information)

H03M 3/02 (2006.01); H03M 7/36 (2006.01); H04B 14/06 (2006.01); H03M 7/00 (2006.01)

CPC (invention and additional information)

H03M 3/458 (2013.01); H03M 7/3028 (2013.01); H03M 7/304 (2013.01)

Designated contracting state (EPC)

DE FR GB IT NL

DOCDB simple family

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 20031205; JP 2002510455 A 20020402; KR 20010012348 A 20010215; MY 133001 A 20071031; NO 992777 A 19990728; NO 992777 D0 19990608; TW 408531 B 20001011