Methods and systems for determining an offset term for a synthesizer signal, and methods and systems for producing a phase-corrected digital signal

US8644783B2 · kind B2 · utility

Assignee

• u-blox AG · CH

Inventor

• Thomas Brauner · Berlin, DE

Key dates

• Filing date: Mar 19, 2012
• Grant date: Feb 4, 2014
• Expiry date: Jul 27, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S19/29
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A fractional-N PLL synthesizer has an up-down counter counting up for positive edges of a frequency-divided signal produced by a frequency divider with a fractional divide ratio in a feedback path of the synthesizer and down for positive edges of a reference signal. A phase offset between portions of the synthesizer signal before and after a loss-of-lock interval is then assessed as a numerical value proportional to the product of the divide ratio and the cycle difference registered by the up-down counter (36) after the loss-of-lock interval. A correction term derived from the phase offset can be used in a signal processing device as employed, e.g., in a GNSS receiver, for producing, from an analog input signal, a phase-corrected baseband signal where portions of the signal before and after loss of lock are phase coherent.