US 7,321,640 B2
Active polyphase inverter filter for quadrature signal generation
Gregory L Milne, Winter Springs, Fla. (US); Michael W Rawlins, Lake Mary, Fla. (US); and Gregory S Rawlins, Heathrow, Fla. (US)
Assigned to ParkerVision, Inc., Jacksonville, Fla. (US)
Filed on Jun. 04, 2003, as Appl. No. 10/453,622.
Claims priority of provisional application 60/386484, filed on Jun. 07, 2002.
Prior Publication US 2003/0227983 A1, Dec. 11, 2003
Int. Cl. H03D 3/22 (2006.01)
U.S. Cl. 375—330  [375/302] 22 Claims
OG exemplary drawing
 
1. A quadrature signal generator, comprising:
a coarse stage for generating output signals that have substantially a quadrature phase relationship, said coarse stage having at least one 90/180 delay circuit having a first set of inverters and a second set of inverters, said second set of inverters having an approximate delay of 90 degrees relative to said first set of inverters; and
at least one refinement stage for refining said quadrature phase relationship of said output signals from said coarse stage, said refinement stage having at least one 0/180 delay circuit, said 0/180 delay circuit having a third series of inverters and a fourth series of inverters, said fourth series of inverters having an approximate delay of 180 degrees relative to said third series of inverters.