Title:
【発明の名称】電子的フィルタ
Document Type and Number:
Japanese Patent JP3307923
Kind Code:
B2
Abstract:
An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter (81) having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus (85), electroacoustic systems, hearing aids and methods are also disclosed.
Inventors:
Robert E. Morley, Giunia
A Maynard Engeblettsson
Jioji El Engel
Thomas The Ray Sullivan
A Maynard Engeblettsson
Jioji El Engel
Thomas The Ray Sullivan
Application Number:
JP9171589A
Publication Date:
July 29, 2002
Filing Date:
April 11, 1989
Export Citation:
Assignee:
Co/esho mppee
International Classes:
H04R25/04; H03H17/02; H03H19/00; H03H21/00; H03M1/66; H04R3/04; H04R25/00; H04R25/02; (IPC1-7): H03H21/00; H03H19/00; H04R25/00
Domestic Patent References:
| JP62291212A | ||||
| JP616921A | ||||
| JP58202619A | ||||
| JP62155679A | ||||
| JP62132479A | ||||
| JP5729971A | ||||
| JP634796A | ||||
| JP62284530A | ||||
| JP5792927A | ||||
| JP572115A | ||||
| JP572114A |
Attorney, Agent or Firm:
Hiroshi Tanaka