EXPLORING THE SAMPLING RATE REQUIREMENTS FOR BEHAVIOURAL AMPLIFIER MODELLING

David H. Wisell

Abstract

In this paper it is shown that for the purpose of nonlinear power amplifier behavioural modelling, the sampling rate can be set to the Nyquist rate of the input signal, rather than to the Nyquist rate of the output signal by making use of Zhu’s generalized sampling theorem. This claim is supported by measurements on a basestation power amplifier. The findings are that the model error obtained when the output signal is sampled at the Nyquist rate of the input signal is approximately 1.5 dB higher than when the sampling rate is set to the Nyquist rate of the output signal. However, if a sampling rate of twice the Nyquist rate of the input signal is used, which is still typically, much lower than the Nyquist rate of the output signal, the degradation is only 0.2 dB. These are important findings that will substantially ease the requirements on ADCs used in measurement setups used for amplifier modelling.

Keywords

amplifier modelling, generalized sampling theorem, undersampling

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PWC-2006-TC4-005u.pdf

DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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