Inventors:
Benton Holzwarth - Tigard OR
Assignee:
Tektronix, Inc. - Wilsonville OR
International Classification:
G01R 1320
Abstract:
A digital oscilloscope of the type that processes (30) the digital waveform values of the waveform record using interpolation and/or decimation (81) to produce a main trace record (91) and first (92) and second (93) zoomed trace records, and uses those records to produce (40) a main trace display (65) and first (61) and second (62) zoomed trace displays is improved by providing (94) a first zoom box (63) encompassing that portion of the main trace (65) display shown in the first zoomed trace (61) display and a second zoom box (64) encompassing that portion of the main trace (65) display shown in the second zoomed trace (62) display. Controls for the two zoom boxes are ganged together so that they both have a horizontal-time dimension determined (85) by a relationship between horizontal-time settings of the first zoomed trace display and horizontal-time settings of the main trace display and vertical-amplitude dimensions determined (87) by a relationship between vertical-amplitude settings of the first zoomed trace display and vertical-amplitude settings of the main trace display. The horizontal-time separation between the first and second zoomed displays, and therefore the two zoom boxes, is controllable (50) by an operator and provided as a readout (66) for measurement convenience.