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

EPO simple patent 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

INPADOC legal status


2008-12-31 [18R] REFUSED

- Effective date: 20081103

2006-04-05 [RIN1] INVENTOR (CORRECTION)

- Inventor name: LIPASTI, LAURI

2006-04-05 [RIN1] INVENTOR (CORRECTION)

- Inventor name: KOVANEN, ARHIPPA

2003-08-27 [17Q] FIRST EXAMINATION REPORT

- Effective date: 20030715

2003-05-02 [A4] SUPPLEMENTARY SEARCH REPORT

- Effective date: 20030313

2003-04-16 [RIC1] CLASSIFICATION (CORRECTION)

- IPC: 7H 04B 14/06 A

2003-04-16 [RIC1] CLASSIFICATION (CORRECTION)

- IPC: 7H 03M 7/00 B

2000-07-26 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 19991021

2000-07-26 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): DE FR GB IT NL