title: A speed and frequency substandard for tachograph calibration equipment.
abstract: The process of calibrating a tachograph makes use of a mechanical head drive unit and an electronic clock tester. Both these devices should be checked against a standard at 6-month intervals. The design of such a substandard, based on a highly stable 1 MHz crystal oscillator, is described.
mesh_terms: D000063:Accidents, Traffic; D002138:Calibration / Q000592:standards; D004581:Electronics / Q000295:instrumentation; D004864:Equipment and Supplies / Q000592:standards*; D005554:Forensic Medicine; D006801:Humans