A Time Base Option for Arbitrary Selection of Sample Rate in Digital Storage Oscilloscopes

The design and implementation of a time base system that allows arbitrary selection of the sample rate in digital storage scopes with very fine frequency resolution is presented. The proposed solution relies on a suitable memory management strategy and a short digital filter with dynamically generated coefficients. It represents an alternative to the use of external clocks, which, due to the bandwidth restriction of the external path, can effectively be used to control the sample rate only on a limited portion of the whole range. The value of the proposed solution consists of widening the functionalities of general-purpose instruments such as digital storage oscilloscopes (DSOs) with limited impact on precision.