Patent ID: 7702044

Claim:
A wireless network device, comprising: a correlation module that correlates a predetermined portion of a radio frequency (RF) signal and that generates a correlation signal based on said correlation of said predetermined portion; an automatic gain control (AGC) module that generates a gain control signal based on said RF signal; a converter module that converts said RF signal to a digital RF signal; and a control module that selectively determines whether said RF signal is a radar signal based on said correlation signal and said gain control signal, and that generates a reset signal that resets said AGC module when a value of said digital RF signal decreases to less than a predetermined value, wherein said control module: divides said digital RF signal into N equal segments during a period between said gain control signal and said reset signal that follows said gain control signal, where N is an integer greater than one; counts zero-crossings in each of said N equal segments; determines a first difference between said zero-crossings in a first one of said N equal segments and said zero-crossings in a second one of said N equal segments; determines that said RF signal is a chirp radar signal when said first difference is greater than or equal to a first predetermined threshold; and determines that said RF signal is a tone radar signal when said first difference is less than said first predetermined threshold.