methods and apparatus are disclosed for automated meter reading systems for determining quantities of a consumed utility product including electric , gas , and water service , using wireless data transfer . to compensate for the frequency drifts of the transmitters , these methods and apparatus , with minimum pre - processing of the received data , allow for on - the - fly adjustability of receiver bandwidth by merely changing a pre - calculated weighting function . as such , it is possible to use a fixed size discrete fourier transform , or in particular a fixed n - point fast fourier transform , for signals of different bandwidths .