Multi-Rate Signal Processing for Obtaining Higher-Order Derivatives of Low-Frequency Signals

摘要

In this paper, a multi-rate signal processing technique is pro posed for obtaining the higher-order derivatives of digital signals with an improved signal-to-quantization noise ratio (SQNR). Th e technique consists of an oversampling analog-todigital conversion (ADC) unit with a dithering process and a multi-stage down sampling process followed by a high performance digital differentiator with a down sampler using a factor of 2. In the cascaded multi-stage process, each stage contains a simple half-band low-pass filter with the same down sampler using a factor of 2. The proposed technique uses an extremely small finite impulse response (FIR) filter size; h ence, it req uires much less memory and computations in comparison to the single-stage process. Both computer simulations and experimental data processing demonstrate the effectiveness of the proposed method.