Stanford FS725 Benchtop Rubidium Frequency Standard
Time/Frequency Instruments (Distributed only in Germany.)
Operation
| Output frequencies | 10 MHz sine, 5 MHz sine, 10 ms wide 1 pps pulse |
| 10 MHz / 5 MHz amplitude | 0.5 Vrms, ±10% (1.41 Vpp or +7 dBm) |
| 1pps pulse amplitude | 2.5 V into 50W, 5 V into HiZ |
| Phase noise (SSB) | <-130 dBc/Hz (10 Hz) <-140 dBc/Hz (100 Hz) <-150 dBc/Hz (1 kHz) <-155 dBc/Hz (10 kHz) |
| Spurious | <-100 dBc (100 kHz BW) |
| Harmonics | <-60 dBc |
| Accuracy at shipment | ±5 ´ 10-11 |
| Aging (after 30 days) | <5 ´ 10-11 (monthly) <5 ´ 10-10 (yearly) 5 ´ 10-9 (20 years, typical) |
| Short term stability (Allan variance) |
<2 ´ 10-11 (1 s) <1 ´ 10-11 (10 s) <2 ´ 10-12 (100 s) |
| Holdover | 72 hour Stratum 1 level (1 ´ 10-11) |
| Frequency retrace | ±5 ´ 10-11 (72 hrs off, then 72 hrs on) |
| Settability | <5 ´ 10-12 |
| Trim range | ±2 ´ 10-9 (0 to 5 VDC) ±0.5 ppm (via RS-232) |
| Warm-up time | <6 minutes (time to lock) <7 minutes (time to 1 ´ 10-9) |
| Front Panel Indicators (Green LEDs) | |
| Power | ``On" when AC power is applied |
| Locked | ``On" when frequency is locked to rubidium |
| 1pps input | Blinks with each 1 pps reference input applied to rear panel |
| 1pps sync | ``On" when 1 pps output is synchronized within ±1 m s of 1pps input |
| Receive | Blinks ``on" when RS-232 characters are received by FS725 |
| Send | Blinks ``on" when RS-232 characters are sent by FS725 |
| Rear Panel Connections | |
| Frequency Adjust | 0-5 VDC to adjust frequency by +/- 0.002 ppm (normally unconnected) |
| 1 pps input | One 100 kW input. Requires CMOS level pulses (0 to 5 VDC). If an external 1 pps input is applied, lock is maintained between the 1 pps input and 1 pps output with computer adjustable time constant from 8 minutes to 18 hours. |
| 10 MHz outputs | Two 50 W isolated 10 MHz sine outputs |
| 5 MHz output | One 50 W, 5 MHz sine output |
| 1 pps output | One 50 W pulse output. |
| Optional outputs | Each option board provides four 10 MHz, one 5 MHz and one 1 pps outputs. Up to 3 boards may installed. |
| Alarm relays | Max current, 3 A. SPDT, normally open or normally closed. May be wired in parallel with other relays to ``wire-or" a single alarm. |
| Rb lock | Relay status matches the front panel ``Locked" LED. |
| 1 pps | Relay status matches the front panel ``1 pps sync" LED |
| RS-232 | 9 pin connector configured as DCE, 9600 baud. Windows RbMon Software is provided. |
| Environmental | |
| Operating temperature | +10 °C to +40 °C |
| Temperature stability | Df/f <±1 ´ 10-10 (+10 °C to +40 °C) |
| Storage temperature | -55 °C to +85 °C |
| Magnetic field | Df/f <2 ´ 10-10 for 1 Gauss field reversal |
| Relative humidity | 95% (non-condensing) |
| General | |
| AC power | 90 to 132 VAC or 175 to 264 VAC, 47 to 63 Hz, 50 Watts |
| Dimensions | 8.5"´3.5"´13" (WHL) |
| Weight | 9 lbs |
| Warranty | One year parts and labor on materials and workmanship |
