Abstract: A portable data collector and analyzer apparatus and method provides predictive and preventative maintenance of a multiplicity of assets through the use of a unique architecture that allows a variety of different application programs to be downloaded to the apparatus for providing a single multi-purpose portable data collector and analyzer apparatus that can employ the variety of different application programs for configuring, inter alia, different measurements types, different transducers types and different signal processing types for collecting and analyzing sensed physical data from a variety of different assets found in industrial plants. A unique frequency shifting and decimation method is employed for spectrum calculation that, inter alia, retains DSP addressing efficiency and increases signal processing speed. Additionally, a unique synchronous sampling method is employed that generates synchronous sample waveforms from asynchronous sample waveforms.