True dual-timebase arrangement for an oscilloscope

摘要

A dual timebase feature for digital storage oscilloscope includes an A/D converter for producing digital samples of a signal under test. The digital samples are applied to a first decimator for decimating the samples. A second decimator coupled to the output of the first decimator further decimates the samples. A pair of gates selectively couples the outputs of the first and second decimators to a memory. A controller controls one gate to select a high data rate record having a length shorter than an entire data record for storage in memory and for display as a zoom (i.e. detailed) record, and controls the other gate to select a low data rate record encompassing substantially all of said entire data record, for display as an overview record. The subject apparatus produces two data records of different data rates and encompassing different time periods.