Title:
CMOS COMPANDER
Document Type and Number:
Japanese Patent JP3313783
Kind Code:
B2
Abstract:
PURPOSE: To improve the speech quality of a mobile telephone system by integrating the compander in other functions of mobile telephone by controlling a switching capacitor amplifier for a compressor and an expander by an exclusive OR circuit block as dual comparators.
CONSTITUTION: The compander consists of the compressor 17 and expander 18 and programmable clock control switching capacitor(SC) amplifiers 19 to 22 and exclusive OR XOR circuit blocks 23 and 24 as dual comparator are used. The blocks 23 and 24 detect positive and negative peak values of a signal and the XOR circuit outputs level information to control logic parts 25 and 26 to increase and decrease respective gains with logical levels 1 and 0. The control logic parts 25 and 26 are composed of an amplifier control part and a counting part, which prescribes an increase and a decrease in gain, stops counting when a minimum or maximum gain is reached, and makes a transient response time accurate. Consequently, the compander is integrated in other functions of mobile telephone to improve the speech quality of the mobile telephone system.
Inventors:
Joni Pereenen
Mika Grain Ruth
Kim Cartio Cario
Mika Grain Ruth
Kim Cartio Cario
Application Number:
JP27869692A
Publication Date:
August 12, 2002
Filing Date:
October 16, 1992
Export Citation:
Assignee:
Nokia Mobile Phones Limited
International Classes:
H03G3/20; H03G7/00; H03G11/00; H03H19/00; (IPC1-7): H03G7/00; H03G3/20
Domestic Patent References:
| JP2149111A | ||||
| JP505062A | ||||
| JP63253709A | ||||
| JP62202608A |
Attorney, Agent or Firm:
Aoki Akira (4 outside)