1. A method of determining a maximum value of a fast Hadamard transform, said method comprising the steps of: calculating N−1 radix- 2 equivalent stages of an N-stage fast Hadamard transform; calculating a plurality of maximum pair values &verbar;a&verbar;&plus;&verbar;b&verbar;, one for each pair (a,b) of inputs from the N−1 th stage; determining said maximum value from said plurality of maximum pair values; and wherein N is a positive integer.