The SR625 Frequency Counter is a NIST traceable frequency counting standard for calibrating base stations, transmitters and other types of communication systems. The SR625 Frequency Counter consists of frequency counter (SR620), high-accuracy rubidium timebase (PRS10), and 2 GHz input prescaler..sr625的率数器是NIST可校准基站率数标准传感器和其他类型的信系统。sr625的率数器由率数器SR620精度时基prs10和2 GHz入分器..The combination of the SR620 and the prescaler allows direct frequency measurements up to 2 GHz with twelve digits of resolution in a 100s measurement. The rubidium timebase ensures excellent short-term stability (lt;2 times; 10-11 Allan variance (1 s)) and long-term drift (lt;5 times; 10-11/month). The SR625’s warmup time is less than ten minutes rendering it ideal for field applications.的SR620和分器允直接测率2 GHz的十二位分率在100测相结合。时基确保好的短期稳定性lt2倍10-11伦方差1和期漂移lt5倍10-11日/月。sr625的热的时少于十分使其合现场应用。