* ParkerVision falls as much as 76 percent, plans appeal
* Judge says not enough evidence of patent infringement
June 23 (Reuters) - A federal judge in Florida has overturned a jury verdict that had ordered Qualcomm Inc to pay ParkerVision Inc $173 million for infringing patents for technology used in smartphones.
Shares of ParkerVision plunged as much as 76 percent in morning trading on Monday.
In a decision dated June 20, U.S. District Judge Roy Dalton in Jacksonville, Florida, said expert testimony offered by a key ParkerVision witness provided "an insufficient evidentiary basis" for a finding of patent infringement. He also said Qualcomm deserves a new trial if an appeals court disagrees.
"While the court is loath to overturn the jury's verdict, on this record, it is the court's only choice," Dalton wrote.
The judge also let stand the jury's findings that ParkerVision's patents were valid.
ParkerVision Chief Executive Officer Jeffrey Parker said in a statement that he was "obviously disappointed" by the outcome, and that the Jacksonville-based company would appeal.
San Diego-based Qualcomm did not immediately respond to a request for comment.
According to court papers, ParkerVision accused Qualcomm of infringing its patents beginning in 2006 over a means to convert radio frequency signals, and incorporating its technology in products sold for use in mobile devices such as smartphones.
ParkerVision claimed it had sought without success to license the technology to Qualcomm in the late 1990s, only to learn more than a decade later that Qualcomm was using it.
The $173 million award had been seen as a disappointment for ParkerVision, which had sought more than twice as much.
Jurors also rejected ParkerVision's argument that Qualcomm's alleged infringement was willful, which could have resulted in triple damages.
ParkerVision also has a separate lawsuit against Qualcomm and HTC Corp over other patents that relate to radio frequency transmitters.
In morning trading on the Nasdaq, ParkerVision shares were down 64.9 percent at $1.77 after falling to $1.21. Qualcomm dipped 0.5 percent to $79.43.
The case is ParkerVision Inc v Qualcomm Inc, U.S. District Court, Middle District of Florida, No. 11-00719.
(Reporting by Jonathan Stempel in New York; Editing by Lisa Von Ahn)