Frequency Electronics, Inc. FEI-Zyfer, Inc.
GPS Time and Frequency Systems

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System Features:

High Performance:  
     Compact, Flexible
     Fully Featured

4 I/O Module Slots
     100+ Option Modules

 GPS Receiver:
Standard Civil C/A-Code
     and/or SAASM MPE-S
     Force 22E MRU Military

 User Interface:
Standard RS-232
     Optional Ethernet I/O
     (Telnet, SNMP)
     Keypad, LCD display

 Remote Access Utility:
     Zyfer™ Monitor

 Standard Outputs:
1 PPS, 10 MHz
(Rear Panel)

All units are calibrated
     with an in-house
     standard traceable
     to UTC


GSync Model 391

  GSync is the 1U compact chassis version of the popular and versatile CommSync II. The heart of the GSync is the GTF (GPS Time and Frequency) module within the unit. It is self-contained with a Quartz or Rubidium oscillator, and a commercial C/A GPS receiver or a military SAASM GPS receiver (either a Rockwell-Collins MPE-S GB-GRAM or a Trimble Force 22E MRU).

If a system needs a Primary Reference Source (PRS), the GSync provides either Standard Positioning Service (SPS) GPS (the civil C/A signal) or the very latest in GPS military technology - SAASM Precision Positioning Service (PPS) GPS receivers (for approved users only). With GPS as the reference source, the GSync provides a frequency accuracy of 1E-12 and a time accuracy of < 50 ns Peak to UTC, for calibrated units.

The GSync is also designed to take external inputs to provide internal frequency synchronization to the accuracy of the external source. There are two choices of disciplined oscillator selection. Depending on holdover requirements, an Ovenized Quartz Crystal Oscillator (OCXO) or a Rubidium Atomic Oscillator can be specified. The GSync can be
populated with up to (4) option modules.

There are a wide variety of output option modules available: Low-Phase Noise sine wave, T1/E1, Time Code, and Network Time Protocol (NTP). The full line of common GSync and CommSync II option modules are shown in the option module listing on our web site.
For Monitor and Control functions there is an RS-232 communication port on the rear panel of the chassis and a standard Ethernet port providing Telnet, SNMP, and Network Time Protocol (NTP), as well as PTPv2 IEEE 1588-2008.

FEI-Zyfer products come with a standard 2 year factory warranty (parts & labor).
   Rear Panel View  


Antenna / Comm
1 PPS / 10 MHz,
RJ-45 Ethernet

4 Input/Output
Hot-Swappable Option Module Slots

Power Supply
AC or DC


 Available Option Modules for CommSync II and GSync Products

Power Options System
Time Modules Clock Rate
 Output Specifications (a)
  Frequency Accuracy:  
 24 Hour Average  Rubidium Oscillator  Quartz Oscillator
 Locked to GPS  < 1E-12  < 1E-12
 Holdover (b) - first 24 hours  < 5E-11  < 1E-10
  Time Accuracy: - to UTC, for calibrated units (c)  
   Rubidium Oscillator  Quartz Oscillator
 Locked to GPS  < 50 ns Peak  < 50 ns Peak
 Holdover (b) - first 24 hours  < 3 μs  < 7 μs
  Short Term Stability (d) typical:  
 Allan Deviation  Rubidium Oscillator  Quartz Oscillator
 1 sec  < 3E-11  < 1E-11
 10 sec  < 1E-11  < 1E-11
 100 sec  < 3E-12  < 1E-10
  Phase Noise (d) typical:  
   Standard Output  Low Noise 5MHz
 1 Hz  < -90 dBc/Hz  < -105 dBc/Hz
 10 Hz  < -105 dBc/Hz  < -130 dBc/Hz
 100 Hz  < -125 dBc/Hz  < -150 dBc/Hz
 1 kHz  < -135 dBc/Hz  < -158 dBc/Hz
 GPS Receiver Options
 Standard GPS Receiver - Civil C/A-Code:
 Type:  8 to 12 channel, independent tracking
 Frequency:  1575.42 MHz (L1)
 Code:  C/A
 Acquisition Time:  Warm Start: < 2 minutes, Cold Start: < 20 minutes.
 SAASM GPS Receiver - Military P(Y)-Code:
 Type:  12 channel, independent tracking
 Frequency:  1575.42 MHz and 1227.60 MHz (L1 & L2)
 Code:  C/A and P(Y)
 Acquisition Time:  Warm Start: < 2 minutes, Hot/Cold Start: Dependent on
 Initialization Device
 Keyload Interface:  DS-102
 FORCE 22E MRU SAASM GPS Receiver - Military C/A and P(Y)-Code: (e)
 Type:  24 channel, simultaneous tracking of L1, L2 and C/A codes
 Frequency:  1575.42 MHz and 1227.60 MHz (L1 & L2)
 Code:  C/A and P(Y)
 Acquisition Time: (c)  Warm Start: < 2 minutes
 Hot/Cold Start: Dependent on Initialization Device
 Keyload Interface:  DS-102
 Standard Input/Output
 Rear Panel (All models)  
 1 PPS, 50 Ω, TTL level, BNC, Ext. Sync Input  
 RS-232 I/O connector  
 10 MHz, 50 Ω, TTL level, BNC connector  
 1 PPS, 50 Ω, TTL level, BNC connector  
 GPS Antenna, TNC connector  
 RJ-45 Fast Ethernet  
 SAASM Front Panel  
 1 Keyload connector, 1 Hot Start connector, 1 Zeroize button
 Power Options
 AC or DC Power Supply
 AC Input (115/230 VAC)  100-120 and 200-240 VAC, 100 Watts maximum, 47-63 Hz
 DC Input (24 VDC)  18 to 36 VDC, 100 Watts maximum
 DC Input (48 VDC)  36 to 76 VDC, 100 Watts maximum
 DC Input (12 VDC)  11.5 to 18 VDC, 150 Watts maximum
 DC Input (28 VDC aircraft bus)  22 to 29 VDC, 150 Watts maximum
 Chassis Physical Dimensions
 Height:  44 mm (1.75") (1U)
 Width:  448 mm (17.65) (19" EIA Rack)
 Depth:  381 mm (15.0") including connectors
 Weight:  10 lbs. (max.)
 Operating Temperature:  0° C to 50° C
 Rate of Change:  10° C/Hour
 Storage Temperature:  -40° C to +85° C
 Relative Humidity:  5 % to 95 %, non-condensing
 Altitude, Operating:  -60 m to 4000 m
 Altitude, Storage:  -60 m to 9000 m
 EMC / EMI: FCC Code of Federal Regulations 47CFR Part 15, Subpart B, Class B
(a) After 24 hours of GPS locked operation, fixed antenna location, antenna delays entered.
(b) After 48 hours of continuous operation.
(c) 2σ (95.5 % probability).
(d) Detailed specifications for various output modules: See "Option Module User's Manual 385-8003".
(e) U.S. Government policy restricts the sale of Precise Positioning Service (PPS) equipment to those
authorized by the U.S. Department of Defense. Non-U.S. authorized users must purchase PPS equipment
through the Foreign Military Sales (FMS) process.
(f) Dependent on the accuracy of initialization parameters from PLGR or DAGR handheld SAASM GB-GRAM receivers, or other initialization devices.
(g) Located on front panel.

Product specifications subject to change without notice.


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