SDH/PDH分析仪抖动发生器的校准

Anautomatic jittercalibration system for jitter generatoraccuracyin SDH/PDH analyzer

本文介绍了上海市计量测试技术研究院建立的有线数字通信检测装置中SDH/PDH分析仪抖动发生器校准系统,本系统可以校准高达10Gbit/s的电口和光口的抖动发生器输出抖动,所使用的标准仪器为频谱分析仪、75Ω/50Ω阻抗变换器和用于光输出信号抖动校准的O/E转换器。校准方法为Bessel函数的比值法和宽带调频法,对于小抖动值,则使用Bessel函数比值法;而对于JJG(YD)044-1998SDH数字传输分析仪检定规程中所需要校准的10UIp-p的抖动,则使用宽带调频法与比值法相结合。用NI公司的Labview软件编写了抖动自动测试软件,通过与信息产业部通信计量中心对同一台装置同一组数据的校准结果比较,表明二者之间相当一致,证明了本抖动发生器校准系统方案设计合理,计量准确可靠。

This article introduces the calibration system of jitter generator used in SDH/PDH analyzer which is part of the digital wire communication measurement system built at Shanghai Institute of Measurement ＆ Testing Technology （SIMT）, As high as 10Gbit/s jitter output of the jitter generator with either electrical or optical port can be calibrated with the system, the instruments utilized include E4440 spectrum analyzer,75Ω/50 Ω impedance adapter and 83440C O/E converter dedicated for jitter calibration of optical output signal. Ratio of Bessel Function and Wide-band FM （WBFM） are adopted as calibration approaches, for small jitter value Ratio of Bessel Function approach is used whereas the combination of Ratio of Bessel Function and WBFM approach is used when calibrating the 10Ulp-p jitter accuracy required by JJG （YD） 044-1998 Regulation of Verification for SDH Transmission Analyzer. Automatic measurement software was also made with Labview from NI to improve measurement efficiency. The measurement results were compared with the same group of results from the same equipment measured by Metrology and Calibration Center of MII, the conclusion is that they are quite close to each other, which approves that the approach to realize the calibration system is rational and credible and the results are accurate and reliable.