METHODS AND APPARATUSES FOR ESTIMATION AND COMPENSATION OF NONLINEARITY ERRORS

摘要

An estimation unit (30, 30a-c) for estimating a nonlinearity error of a conversion circuit (10), such as an ADC, adapted to receive a continuous-time input signal and output a digital output signal. The continuous-time input signal is essentially bandlimited to an angular frequency band [ω1, ω2 ], where ω1 (L-1)π/T, ω2Lπ/T, L is a positive integer, and T is a sample period of the conversion circuit. The estimation unit (30, 30a-c) comprises an input port (32, 32a-c) for receiving a digital input signal having a first sample rate 1/T and an output port (34, 34a-c) for outputting a digital estimated error signal also having the first sample rate. For each integer P_k in a set of integers, the estimation unit comprises a first linear filter unit (100-k) for generating a first signal s1(n) as a linear function of the digital input signal, an interpolation unit (105-k) for interpolating the first signal s1(n) to generate a second signal s2(m) having a second sample rate which is a factor L⋅R_k higher than the first sample rate, wherein L⋅R_k ≥ ω2⋅T⋅P_k/π, a nonlinearity unit (110-k) for generating a third signal s3(m) as (s2(m))P_k, and a second linear filter unit (115-k) for generating a component of the estimated error signal based on the third signal s3(m), wherein said component has the first sample rate. Furthermore, the estimation unit comprises an adder circuit (117) for generating the estimated error signal as the sum of the components of the estimated error signal. Moreover, a compensation circuit (20) comprising the estimation unit, corresponding methods for estimating and compensating nonlinearity errors, a computer program product, a computer readable medium, and a hardware-description entity are also disclosed.