Patent Number: 6,298,227

Title: Method and apparatus for frequency conversion for a receiver with a limited-accuracy oscillator

Abstract: A frequency converter that converts a signal at a radio frequency to an intermediate frequency using a limited-accuracy local oscillator. The frequency converter is configured to receive an analog signal at a first frequency and convert the analog signal to an intermediate frequency using the local oscillator. The frequency converter also includes an analog-to-digital converter to convert the intermediate frequency signal to a digital representation of the signal, and a plurality of digital filters, each configured to filter the digital representation of the signal by a frequency offset, each digital filter using a different frequency offset. There are also a plurality of correlators equal in number to the plurality of digital filters and each configured to generate a correlation of the filtered digital representation of the signal to known synchronization words shifted by the frequency offset of its respective digital filter. A selector is configured to derive a final frequency offset from the plurality of correlation results as a correction factor for the baseband signal.

Inventors: Molnar; Karl J. (Cary, NC)

Assignee: Ericsson Inc.

International Classification: H03J 7/02 (20060101); H04B 1/28 (20060101); H04B 001/26 ()

Expiration Date: 10/02/2018