Patent ID: 7129873

Claim:
A variable-order delta sigma modulator comprising: a plurality of integrators arranged in sequence to have a construction that supplies an output signal from one said plurality of integrators to at least one integrator of a next-stage; means of disconnecting or connecting circuits, provided in connection parts to supply the output signal to the next stage integrators; a quantization error circuit coupled to the outputs of said plurality of integrators and adapted to generate a quantization error; a circuitry to feed back said quantization error to the input of said one plurality of integrators; means of controlling the disconnecting or connecting means on the basis of a detected or set sampling frequency, whereby an order of the modulator is made variable in relation to the detected or set sampling; and a control means that switches the order of the modulator into an order optimum to a new sampling frequency, accompanied with the switching of the sampling frequency, on the basis of a table showing connections or disconnections of the integrators by the means that vary the order of the delta sigma modulator and the combination of plural integrators, and a table showing relations between the sampling frequencies and the optimum orders.