systems and methods are described for providing a reconfigurable circuit having multiple distinct circuit configurations with respective distinct operating modes the circuit may be controllably configures to perform a fast fourier transform function , a multiplier function , and a divider function . in one exemplary practical application of the invention , the fast fourier transform function , multiplier function , and divider function may be used for signal demodulation , channel equalization and channel estimation for a wlan ieee 802 . 11 system .