Frequency Standards FS740 — GPS/GNSS Time and Frequency System FS740 GNSS Time and Frequency System · GPS/GNSS disciplined 10 MHz · 1 × 10−13 long-term stability · Time tag events to UTC or GPS · Sine, square, triangle, IRIG-B output The FS740 GPS/GNSS Time and Frequency System provides a 10 MHz frequency reference with a long-term stability of better than 1 × 10–13. The instrument can also time tag external events with respect to UTC or GPS and measure the frequency of user inputs. The instrument has DDS synthesized frequency outputs, adjustable rate (and width) pulse outputs, and an AUX output for arbitrary waveforms including an IRIGB timecode output. · Frequency counter with 12 digits/s Standard, OCXO, or Rubidium Timebase · Built-in distribution amplifiers The standard timebase provides 1 × 10–9 short-term frequency stability and phase noise of less than –100 dBc/Hz (10 Hz offset). An optional OCXO (ovenized crystal oscillator) timebase provides 1 × 10–11 short-term frequency stability and phase noise of less than –130 dBc/Hz (10 Hz offset). An optional Stanford Research Systems

FS740 Time and Frequency System rubidium timebase provides 1 × 10–12 short-term frequency stability, phase noise of less than –130 dBc/Hz (10 Hz offset), and a long-term holdover (lost GNSS signal) of better than 1 μs/day. SRS timing receivers require a net gain (after cable losses) of +20 dBi to +32 dBi, which is a very common level from a variety of available active antennas and typical cable lengths. The antenna input to SRS timing receivers have a female BNC connector, provide +5 V bias, and have a 50 Ω input impedance. SRS offers two antenna solutions, both of which have LNAs. All systems...

FS740 Time and Frequency System Graphical User Interface A graphical user interface allows the user to configure the instrument and see the results of time and frequency measurements. The instrument can be configured in one of three modes: There are two user inputs (one on the front, one on the rear-panel) for frequency and time tag events. The inputs have adjustable thresholds and slopes. Frequencies are measured with a precision of 1 × 10–11 in 1 s, 1 × 10–12 in 10 s, and 1 × 10–13 in 100 s. Time tags are reported with 1 ps resolution which is comparable to the short-term stability of the OCXO...

Oscillator type Temp. Stability Aging Phase noise (SSB) Stability Holdover OCXO Timebase Oscillator type Temp. Stability Aging Phase noise (SSB) Stability Rubidium Timebase Oscillator type Physics package Temp. Stability Aging Phase noise (SSB) Stability GNSS Receiver Satelite acq. time Almanac acq. time Optimized for static applications Oven controlled, 3rd OT, AT-cut crystal <2 x 10-6 (20 to 30 °C) <5 ppm/year (undisciplined to GPS) <-105 dBc/Hz (typical) See graphs next page <40 ps / 24 hr. Oven controlled, 3rd OT, SC-cut crystal <2 x 10-9 (20 to 30 °C) <0.2 ppm/year (undisciplined to GPS)...

Computer Interfaces Ethernet (LAN) RS-232 General AC power EMI Compliance Dimensions Weight Warranty 10/100 Base-T. TCP/IP & DHCP 4.8k-115.2k baud, RTS/CTS flow 90 to 264 VAC, 90 W 47 to 63 Hz with PFC FCC Part 15 (Class B), CISPR-22 (Class B) 8.5” x 3.5” x 13” (WHL) 10 lbs. One year parts and labor on defects in materials and workmanship SRS Stanford Research Systems Ordering information FS740 GPS Time and Frequency System $2950 Option 01 OCXO timebase $650 Option 02 Rubidium timebase $1500 Option A Five 10 MHz outputs $495 Option B Five Sine/Aux outputs $495 Option C Five Pulse outputs $495