A receiver or spectrum determiner includes stages, Fourier transforms, phase delays and a summer. The stages are coupled are in pipelined fashion along a signal path. Each of the stages has a respective output for providing at least one respective demodulated signal for the stage. The Fourier transforms are for receiving the respective demodulated signal and providing a respective Fourier transform. The phase delays each have a delay associated with the respective stage. Each phase delay is for receiving the respective Fourier transform and providing a respective phase delayed transform in accordance with the respective stage. The summer is for summing the respective phase delayed Fourier transform from each phase delay. The receiver can be an electronic intelligence (ELINT) receiver.