US PATENT SUBCLASS 381 / 71.5
.~ Within duct
Current as of:
June, 1999
Click
HD
for Main Headings
Click for
All Classes
Internet Version by
PATENTEC
© 1999
Terms of Use
381 /
HD
ELECTRICAL AUDIO SIGNAL PROCESSING SYSTEMS AND DEVICES
71.1
DF
ACOUSTICAL NOISE OR SOUND CANCELLATION
{7}
71.5
.~ Within duct
DEFINITION
Classification: 381/71.5
Within duct:
(under subclass 71.1) Subject matter wherein the noise cancellation system cancels noise propagating in a tube, canal, pipe, or similar conduit, including automobile inlet and exhaust pipes.