ISO INTERNATIONAL STANDARD 19235 First edition 2015-10-15 Analogue quartz clocks Timing accuracy Horloges analogiques a quartz - Précision du temps Reference number IS0 19235:2015(E) SO Institute of Sta dardization5956617 IS02015 vided by IHS under Not for Resale, 2015/11/30 07:16:53 itted without license from IHS IS0 19235:2015(E) COPYRIGHTPROTECTEDDOCUMENT IS02015,PublishedinSwitzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org Intenationaibr PrganizationforStandardization Not for Resale, 2015/11/30 07:16:53 etworking permitted without license from IHS IS0 19235:2015(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. ..1 2 Terms and definitions 3 Basic parameters and requirements of timing accuracy 3.1 Mean instantaneous rate .1 3.2 Voltage coefficient, Cu. .1 3.3 Temperature coefficient, Ct 2 4 Test methods. .2 4.1 Test conditions. .2 4.1.1 Test environment 2 4.1.2 Power supply .2 4.1.3 Pre-running .2 4.2 Test apparatus. .2 4.3 Testing 2 4.3.1 Mean instantaneous rate .2 4.3.2 Voltage coefficient, Cu. 4.3.3 Temperature coefficient, Ct ..3 Annex A (informative) Main factors affecting the timing accuracy .5 Annex B (informative) Timing accuracy expressions of quartz clocks .6 Bibliography. 7 iii see=Zhejiang Institute of Standardization 5956617 vided by IHS underI ithout license from IHS