JJG 722-2018 English PDF

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JJG 722-2018: Standard Digital Clocks
Status: Valid

JJG 722: Historical versions

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
JJG 722-2018	419	Add to Cart	4 days	Standard Digital Clocks	Valid
JJG 722-1991	399	Add to Cart	3 days	Verification Regulation of Standard Digital Clock	Obsolete

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GB/T 3222.1   JJF 1234   JJF 1396   JJG 802   JJG 488   JJG 238   

Basic data

Standard ID: JJG 722-2018 (JJG722-2018)
Description (Translated English): Standard Digital Clocks
Sector / Industry: Metrology & Measurement Industry Standard
Classification of Chinese Standard: A57
Word Count Estimation: 18,184
Date of Issue: 2018-02-27
Date of Implementation: 2018-08-27
Older Standard (superseded by this standard): JJG 722-1991
Regulation (derived from): AQSIQ Announcement No. 26 of 2018
Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine

JJG 722-2018: Standard Digital Clocks

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Standard Digital Clocks National Metrology Verification Regulations of the People's Republic Standard digital clock Published on.2018-02-27 2018-08-27 implementation The General Administration of Quality Supervision, Inspection and Quarantine issued Standard digital clock Replace JJG 722-1991 Focal Point. National Time Frequency Measurement Technical Committee Drafting unit. Beijing Oriental Metrology and Testing Institute China Institute of Metrology This procedure entrusts the National Time Frequency Measurement Technical Committee to explain Drafters of this procedure. Li Jun (Beijing Oriental Metrology and Testing Institute) Wang Weibo (China Institute of Metrology) Wei Wei (Beijing Oriental Metrology and Testing Institute)

table of Contents

Introduction (II) 1 Scope (1) 2 References (1) 3 Overview (1) 4 Metrological performance requirements (2) 4.1 Main oscillator frequency (2) 4.2 Display time (2) 4.3 Synchronization deviation (2) 4.4 Delay amount (2) 4.5 clock speed (2) 4.6 Frequency long-term parameters (2) 5 General technical requirements (2) 5.1 Appearance and Accessories (2) 5.2 Normal work (3) 6 measuring instrument control (3) 6.1 Verification conditions (3) 6.2 Verification project (3) 6.3 Verification method (3) 6.4 Certification Certificate (6) 6.5 verification period (6) Appendix A Verification Record Format (7) Appendix B Verification Certificate/Verification Result Notice Format (9)

Introduction

This procedure is based on JJF1002-2010 “Rules for the Preparation of National Metrology Verification Procedures”. This procedure is a revision of JJG 722-1991 Standard Digital Clock. Compared with JJG 722-1991, In addition to editorial changes, the main technical changes in this procedure are as follows. --- update of some technical indicators; --- Increase the type of GNSS timing standard digital clock, and increase the timing stability of the verification project; --- The verification of the acceleration rate project is revised to the frequency long-term parameter item. The previous versions of this procedure are released as follows. ---JJG 722-1991. Standard digital clock verification procedure

1 Scope

This procedure applies to the first verification of a standard digital clock (including the GNSS timing standard digital clock). Continued verification and in-use inspection.

2 reference files

This procedure refers to the following documents. JJF1180 time frequency measurement terminology and definition JJF1403 Global Navigation Satellite System (GNSS) Receiver (Time Measurement) Calibration Specification JJG 181 quartz crystal frequency standard JJG 292 铷 atomic frequency standard JJG 1004 hydrogen atom frequency standard For dated references, only the dated version applies to this Code; any undated quotation The latest version (including all amendments) applies to this procedure.

3 Overview

The standard digital clock (hereinafter referred to as the clock) is a time display device that displays hours, minutes, and seconds in numbers. Main vibration of the clock The device is a quartz crystal oscillator or an atomic frequency standard; the operation mode is divided into autonomous operation mode of the main oscillator and GNSS timing. Step mode, in which GNSS timing synchronization mode decodes time information and receives clock by receiving GNSS satellite signals The main vibrator is locked and tamed to provide high performance standard time. The basic principle is shown in Figure 1. Figure 1 GNSS timing standard digital clock working principle diagram The traditional clock includes three parts in addition to the main oscillator. frequency divider and display unit, synchronization device and precise delay adjustment. ......

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