Patent ID: 7307557
Filing Date: 2007-12-11
Classification: H03F,H03M

Abstract:
1. A noise shaper for shaping a power spectral density of an input signal which consists of signal intervals, wherein each signal interval has a corresponding signal amplitude which is constant for a variable interval duration time of the signal interval, said noise shaper comprising: a calculator having at least one serially connected integrator, wherein each integrator calculates an integrated signal of different order from said input signal, and the calculator calculates an integrated error signal of M-th order according to an equation: wherein T 1 is a time an amplitude of an unquantized signal changes from a first amplitude A 11 to a second amplitude A 12 , T 2 is a time an amplitude of a quantized signal changes from a first amplitude A 12 to a second amplitude A 22 within a predetermined time period T of a clock signal (CLK), wherein 0<T 1 <1, 0<T 2 <1 in an n th clock interval, and k is an index variable; and a weighter which weights each integrated signal with a corresponding adjustable weighting coefficient according to a noise transfer function.