Abstract: A signal processing circuit comprises a difference stage for receiving an input signal to be processed and a feedback signal taken from an output signal of the circuit. The difference stage generates a difference signal corresponding to the difference between the input and feedback signal. An integrator stage is coupled to the difference stage to receive the difference signal and output an integrated signal. A time continuous pulse width modulating stage is coupled to the integrator stage to receive the integrated signal and to modulate the signal with reference to a continuously varying carrier signal. A continuous time feedback path is coupled to the output of the modulating stage and an input or the difference stage. The integrator stage comprises at least two integrators to provide second or higher order integration.