SR625 - Frequency Counter with Rubidium Timebase

2 GHz prescaler input 11-digit frequency resolution (1 s) 10 MHz Rb timebase output Statistical analysis & Allan variance GPIB and RS-232 interfaces Rubidium atomic timebase 11-digit freq. resolution (1 s) Statistics & Allan variance SR625 Frequency Counter w/ Rb Timebase The SR625 Frequency Counter is a NIST traceable frequency counting standard for calibrating base stations, transmitters and many other types of communication systems. It combines the high resolution and wide variety of features found in the counter with the atomic accuracy of a rubidium timebase. FS752 GPS/GNSS DO FS725 Rb Frequency Standard SR620 Frequency Counter FS740 GPS Frequency Std. SG380 RF Signal Generator CG635 Clock Generator FS752 GPS/GNSS DO FS725 Rb Freq. Std. SR620 Freq. Counter FS740 GPS Freq. Std. SG380 RF Sig. Gen. CG635 Clock Generator SR625 Frequency Counter with Rb Timebase The SR625 Frequency Counter is a NIST traceable frequency counting standard for calibrating base stations, transmitters and many other types of communication systems. It combines the high resolution and wide variety of features found in the SR620 counter with the atomic accuracy of a rubidium timebase. Low Drift, High Accuracy The SR625 Frequency Counter consists of a frequency counter (SR620), a high-accuracy rubidium timebase (PRS10), and a 2 GHz input prescaler. The combination of the SR620 and the prescaler allows direct frequency measurements up to 2 GHz with twelve digits of resolution in a 100 s measurement. The rubidium timebase ensures excellent short-term stability (<2 × 10 -11 Allan variance (1 s)) and long-term drift (<5 × 10 -11 /month) . Simple, Portable Operation The SR625's warmup time is less than ten minutes making it ideal for field applications. An additional back-panel output provides a rubidium stabilized 10 MHz signal which can be used to drive other test equipment (e.g., synthesizers or spectrum analyzers). The standard GPIB and RS-232 interfaces allow for complete control and data acquisition from any laboratory computer. The SR625's performance makes it the standard for remote applications or laboratory calibration. Prescaler Sensitivity X Prescaler Sensitivity SR625 Frequency Counter Prescaler Sensitivity SR625 Frequency Counter SR625 Specifications The following specifications relate to the 2.2 GHz prescaler and the rubidium timebase of the SR625. Please see the section on the SR620 for general specifications relating to the counter. Accuracy at shipment <5 × 10 -11 /month, <5 × 10 -10 /year Short term stability 100 s Allan variance 10 minutes to meet short-term stability specification 70 W (at warmup), 100/120/208/240 VAC, 50/60×Hz 10 MHz, 1 Vpp sine wave See graph in Features section 700 mVpp square wave 17" × 3" × 14.5" (WHL) One year parts and labor on defects in materials and workmanship