【国外标准】 Standard Guide for Measuring Some Electronic Characteristics of Ultrasonic Testing Instruments

4.1 The recommended measurement procedures described in this guide are intended to provide performance-related measurements that can be reproduced under the specified test conditions using commercially available test instrumentation. These measurements indicate capabilities of sections of the ultrasonic testing instrument independent of specific transducers or examination conditions. Measurements are made from normally available connectors or test points so that no access to internal circuitry is required. Further, this guide is not intended for service, calibration, or maintenance of circuitry for which the manufacturer's instructions are available. It is intended primarily for pulse echo flaw detection instruments operating in the nominal frequency range of 100 kHz to 25 MHz, but the procedures are applicable to measurements on instruments utilizing significantly higher frequency components. 4.2 These procedures can be applied to the evaluation of any pulse-echo ultrasonic testing instrument which can be described as a combination of the electronic sections discussed in this guide. Note 2: These procedures are not intended to preclude the use or application of equipment for which some or all of the measurement techniques of this document are not applicable. 4.3 An ultrasonic testing instrument that cannot be completely described as a combination of the electronic sections discussed in this practice can be partially evaluated. Each portion of the ultrasonic testing instrument that is evaluated must fit the description for the corresponding section. 4.4 This guide is meant to be used by electronic personnel to evaluate the electronic system components and not the ultrasonic system characteristics. 1.1 This guide describes procedures for electronically measuring the following performance-related characteristics of some sections of ultrasonic instruments: 1.1.1 Power Supply Section:       line regulation,        battery discharge time, and        battery charge time. 1.1.2 Pulser Section:      pulse shape,       pulse amplitude,       pulse rise time, pulse length, and       pulse frequency spectrum. 1.1.3 Receiver Section:        vertical linearity,         frequency response,         noise and sensitivity, and         dB controls. 1.1.4 Time Base Section:      horizontal linearity, and       clock (pulse repetition rate). 1.1.5 Gate/Alarm Section:         delay and width,          resolution,          alarm level,          gain uniformity,          analog output, and          back echo gate. 1.2 This guide complements Practice E317 and is not intended for evaluating the performance characteristics of ultrasonic testing instruments on the inspection/production line. Note 1: No access to internal circuitry is required. 1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.