ParkerVision Inc. (OTCQB: PRKR) announced it has completed appellate briefing in its patent infringement case against Qualcomm Inc., according to a company statement.

The Jacksonville, Florida-based company is appealing an Orlando district court's claim construction ruling that led ParkerVision to stipulate to non-infringement. The case involves ParkerVision's patents related to radio frequency down-conversion technology.

ParkerVision claims Qualcomm has taken contradictory positions in the litigation. The company states that for years, Qualcomm argued ParkerVision's patents required signal down-conversion to occur at or after a capacitor. However, in recent Federal Circuit filings, Qualcomm now argues the case is not about where down-conversion occurs.

"For years now Qualcomm has argued that ParkerVision's patent claims require down-conversion in a specific location and now in their own brief for the first time they claim that was never the argument," said Jeffrey Parker, ParkerVision's chief executive officer.

The district court's ruling was based on issue preclusion, treating the current patents as effectively the same as those in an earlier case. ParkerVision argues Qualcomm's changed position undermines the foundation for that ruling.

ParkerVision contends its patent claims establish down-conversion occurs at a switch, which it says is documented in patent specifications and claim language. The company seeks reversal of the issue preclusion finding and a trial on the merits.

The next phase will be oral arguments before the U.S. Court of Appeals for the Federal Circuit in Washington, D.C. ParkerVision holds an extensive patent portfolio in radio frequency technologies used in wireless communication systems.