Filtering in a receiver that uses log-polar signal processing
Patent 5914990 Issued on June 22, 1999. Estimated Expiration Date: 
November 22, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 22, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesLog-polar signal processing Digital radio receiver having limiter amplifiers and logarithmic detector Dual-mode radio receiver for receiving narrowband and wideband signals Patent #: 5668837 InventorAssigneeApplicationNo. 561746 filed on 11/22/1995US Classes:375/350, By filtering (e.g., digital)375/235, Quadrature channels708/323EqualizerExaminersPrimary: Vo, Don N.Attorney, Agent or FirmForeign Patent References
International ClassH04B 001/10AbstractA log polar digital filter for processing a digitized log polar signal that is a magnitude signal (rin) and an angle signal (PHIin), has a first converter for converting the log polar signal into a converted linear Cartesian signal that includes an in-phase signal (Iin) and a quadrature signal (Qin). A linear Cartesian digital filter, coupled to the first converter, generates a filtered linear Cartesian signal from the converted linear Cartesian signal. The first converter may adapt a linearization of rin and compensate for gain errors introduced in an analog circuit that supplies a signal from which the digitized log polar signal is derived. In another feature, a second converter may also be provided for converting the filtered linear Cartesian signal into a filtered log polar signal that includes a filtered magnitude signal (rfilt) and a filtered angle signal (PHIfilt). | |
