Path: Home > JJ > Page245 > JJG 482-2017

Price & Delivery

US$369.00 · In stock · Download in 9 seconds
JJG 482-2017: Laboratory Standard Microphones(Free-field Reciprocity Method)
Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure
Status: Valid

Std ID	Version	USD	Buy	Deliver [PDF] in	Title (Description)
JJG 482-2017	English	369	Add to Cart	4 days [Need to translate]	Laboratory Standard Microphones(Free-field Reciprocity Method)
JJG 482-2005	English	839	Add to Cart	4 days [Need to translate]	Verification regulation of laboratory standard microphones (free-field reciprocity method)
JJG 482-1987	English	439	Add to Cart	4 days [Need to translate]	Verification Regulation of Standard Condenser Microphones (Free-Field Reciprocity Method)

JJG 482-2017: Laboratory Standard Microphones(Free-field Reciprocity Method)

---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.
(Laboratory standard microphone verification procedures (free field reciprocity method) National Metrology Verification Regulations of the People's Republic Laboratory standard microphone (free field reciprocity law) Released on.2017-11-20 2018-05-20 implementation The General Administration of Quality Supervision, Inspection and Quarantine issued Laboratory standard microphone (free field reciprocity method) verification procedures Microphones (Free-fieldReciprocityMethod) Replace JJG 482-2005 Focal Point. National Acoustic Metrology Technical Committee Drafted by. China Testing Technology Research Institute China Institute of Metrology Shenzhen Institute of Metrology and Quality Inspection This procedure entrusts the National Acoustic Metrology Technical Committee to explain Drafters of this procedure. E Zhiqun (China Testing Technology Research Institute) He Longbiao (China Institute of Metrology) Niu Feng (China Institute of Metrology) Pu Zhiqiang (China Testing Technology Research Institute) Zhang Guoqing (Shenzhen Metrology and Quality Inspection Institute)

table of Contents

Introduction (II) 1 Scope (1) 2 References (1) 3 terms and units of measurement (1) 3.1 Laboratory Standard Microphone (1) 3.2 Reciprocal microphone (1) 3.3 Microphone Sound Center (1) 3.4 Electrical Transfer Impedance (2) 3.5 Acoustic Transfer Impedance (2) 4 Overview (2) 5 Metrological performance requirements (2) 5.1 Frequency response of free field sensitivity level (2) 6 General technical requirements (3) 6.1 Mark (3) 6.2 Calibration Information (3) 7 Measuring instrument control (3) 7.1 Verification conditions (3) 7.2 Verification project (4) 7.3 Verification method (4) 7.4 Processing of verification results (7) 7.5 Verification cycle (7) Appendix A Data of the sound center position of the microphone (8) Appendix B Air attenuation coefficient (9) Appendix C Format of Internal Page of Verification Certificate and Verification Result Notice (10)

Introduction

This procedure is prepared in accordance with the rules given in JJF1002-2010 “Rules for the preparation of national metrological verification procedures”. This procedure is based on the national standard GB/T 20441.1-2010 "Electroacoustic measuring microphones Part 1. Real Laboratory Standard Microphone Specifications and GB/T 20441.3-2010 Electroacoustic Measurement Microphones Part 3. Mining The original method for the free field calibration of laboratory standard microphones using reciprocity technology" to JJG 482-2005 The standard microphone (free field reciprocity method) is revised. Compared with JJG 482-2005, except editorial modification The technical changes are as follows. --- Modified the scope of application of the procedure, adding the LS2 type laboratory standard microphone; --- Modified the verification method and operation steps of the free field sensitivity level. The previous versions of this procedure are released. ---JJG 482-2005; ---JJG 482-1987. Laboratory standard microphone (free field reciprocity method) verification procedure

1 Scope

This procedure is applicable to LS1 and LS2 laboratory standard sound transmissions that meet the requirements of GB/T 20441.1-2010. The first verification, subsequent verification and in-use inspection of the device.

2 reference files

This procedure refers to the following documents. JJG 175-2015 working standard microphone (electrostatic exciter method) JJG 449-2014 octave and fractional octave filter JJF1001-2011 General Measurement Terms and Definitions JJF1034-2005 Acoustic measurement terminology and definition GB/T 3102.7 Acoustics and units GB/T 3947 acoustic terminology GB/T 20441.1-2010 Electroacoustic measuring microphones - Part 1. Specification for laboratory standard microphones GB/T 20441.3-2010 Electroacoustic measuring microphones - Part 3. Reciprocal Primary method for free field calibration of standard microphones 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 terms and units of measure

This procedure uses the quantities and units specified in GB/T 3102.7. The following terms and definitions defined by JJF1001-2011, JJF1034-2005 and GB/T 3947 apply to This procedure. 3.1 laboratory standard microphone laboratorystandardmicrophone Calibration methods can be calibrated to very high accuracy condenser microphones using primary calibration methods such as closed coupling cavity reciprocity. consider The mechanical size and electroacoustic characteristics of the machine depend on strict requirements over time stability and dependence on environmental conditions. [GB/T 20441.1-2010, definition 3.2] 3.2 Reciprocal microphone reciprocalmicrophone For linear passive microphones, the open and reverse transfer impedances of the open circuit are equal in magnitude. [GB/T 20441.3-2010, definition 3.1] 3.3 microphone sound center acousticcentreofamicrophone For transmitting microphones, a given frequency of the sinusoidal signal and a point in the specified direction and distance, around this The point is observed in a small range from which an approximately spherical wavefront of the emission is presented. [GB/T 20441.3-2010, definition 3.3] ...