Method and apparatus for use with received electromagnetic signal at a frequency not known exactly in advance
US9577864B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 2013 |
| Grant date | Feb 21, 2017 |
| Priority date | — |
| Expiry date | Oct 3, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/361
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In a software receiver, a received electromagnetic signal is sampled in “slices”, each having a duration of some multiple of a reference frequency. The samples of each slice are correlated with values in a pair of reference signals, such as sine and cosine, at the reference frequency. This yields a two-tuple for each slice, which two-tuples may be stored. The stored two-tuples can be simply added to arrive at a correlation value of narrower bandwidth than that of any slice taken alone. The stored two-tuples can be taken in sequence, each rotated by some predetermined angle relative to its predecessor in sequence, and the rotated two-tuples summed to arrive at a correlation value with respect to a frequency that is offset from the reference frequency to an extent that relates to the predetermined angle. In this way, the receiver is able to proceed despite the transmitted frequency not being known exactly in advance and does not require prodigious storage or computational resources.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.