The GPS Airborne Approved PTS-SAASM is a frequency standard and complete master clock containing a GPS Rubidium Oscillator. This military timing system is one of the most reliable master clocks on the market today and is used for many of our U.S. security systems.
The definition of SAASM is Selective Availability/Anti-Spoofing Module. The PTS-SAASM is a state of the art frequency instrument offering a wide range of features and time and frequency outputs accurate to < 40ns rms to UTC (USNO) and 1x10-12 respectively.

GPS SA-ASM based with disciplined Rb oscillator. Single and dual redundant

This frequency standard offers a full suite of low phase noise outputs including: IRIG B, Have Quick, 10MHz, 1PPS, serial time navigation messages and provides a complete Network Time Server using NTP (Network Time Protocol).  The built-in web browser provides status information about the GPS system, monitoring of internal time errors and user access to a number of alarm thresholds.  Both single and dual redundant models are available for the PTS-SAASM.

The PTS-SAASM is used as a part of many time and frequency systems Brandywine makes for military customers.  In our November 2010 newsletter, Brandywine shares how they created a large time and frequency master clock system for a customer using the PTS-SAASM. Click here to go to our November Newsletter.


  • GPS disciplined atomic clock
  • Network time server
  • Dual redundant version available
  • Complete remote network control using standard web browser
  • SA-ASM GPS Receiver
  • 10MHz, 1PPS, Irig-B, serial and time codes
  • Timing accuracy < 40ns rms to UTC

This new generation of network appliance is economical and reliable and offers complete remote control and monitoring via a web-browser based interface.

The PTS-SAASM can be used in either a single or dual redundant configuration and in conjunction with one of Brandywine Communications range of Distribution Amplifiers, such as the FTSU-100.

Applications for the popular PTS-SAASM include central time and frequency systems, satellite earth stations, military communication systems, and high availability network time servers.

An extremely accurate internal rubidium oscillator is used as the internal time base that drives all the time and frequency outputs. This rubidium oscillator is disciplined using an advanced control algorithm, ensuring superior holdover performance. The time constants of this algorithm are user-adjustable to suit specific applications.

A low cost rack adapter is available (not shown).

The PTS-SAASM utilizes a 12 channel P(Y) code SAASM GPS receiver. It may also be disciplined to an external 1PPS/HaveQuick time code source.  A 100baseT Ethernet port is provided which is used both for monitoring and control of the instrument and for Network Time Protocol. This interface supports both fixed and dynamic IP address assignment via DHCP.

In addition to configuring the PTS-SAASM, the built-in web browser provides information on GPS, internal monitoring of time errors, and internal parameters of the atomic oscillator. The user may set thresholds of any monitored parameter to trigger an alarm.

A precision 1PPS time mark is available for synchronizing or calibrating other equipment and the IRIG B serial time code allows synchronization to be distributed to other computers, displays, and related equipment requiring precise time.

An ASCII serial port outputs any user-selected time of day message at a 1/sec rate for synchronizing other equipment. The same output port may also be configured to output 50 bit/sec BCD time code in accordance with ICD-GPS-060.

A high stability 10MHz sine wave output provides an ultra-stable, low phase noise frequency reference derived from an SC cut crystal that is locked to the rubidium reference

Product Specifications
Product Data Sheet
User Manual

1 PPS Output  
Connector SMA      
Type 5V 0-pk, 10 microseconds wide      
On Time Rising edge      
Serial Interface    
Port Function Setup and Control      
Connector DB9      
Type RS232      
Baud Rate 300-115,200 (Default 115k N, 8, 1)      
Sine Wave Output      
Number of outputs 1      
Connector SMA      
Frequency 10 MHz      
Level 2.5 Vpp into 50 Ohms      
Harmonic Distortion <25dBc      
Phase Noise (SSB)

Time Code Output 1      
Number of Outputs 1      
Code Format (link sel) IRIG B 1kHz or DC level      
Level 2.2 Vpp 600 Ohms HCMOS      
Connector SMA      
Time Code Output 2      
Number of outputs 1      
Code format 50 bit BCD ICD-GPS-060 or ASCII      
Level (link selectable) RS-232 (4,800, N, 8, 1) or BCD      
Connector DB-9      
ASCII format 1/sec user-programmable string      
Fault Alarm Status      
Output Type HCMOS level      
Output polarity User programmable      
Connector DB-9      
Instrument 0 to + 50°C      
Antenna -40 to +85°C      
Humidity To 95% non-condensing      
Power 110/230 Vac      
Optional Power 24 Vdc, -48 Vdc, 125 Vdc      
Dimensions 3.25” x 7.25”x 15.8”      
With rack mount adapter 19 inch Rack Mount, 3.48” (2U) height, 15.80” depth in rack      
Weight 5.5 pounds, typical      
GPS C/A Code Receiver Specification      
Receiver type Motorola Oncore UT+      
8 channel C/A code timing receiver      
L1 only      
P(Y) Code GPS Receiver Specification Option)
Receiver Type GRAM SA-ASM receiver
Satellite Signal GPS L1, L2 Dual Frequency
Satellite Code C/A, P(Y)
Receiver Type Parallel 12 Channel 12 all-in-view receiver
Position Accuracy 16m SEP in SA/AS environment with
  respect to WGS-84 with CV loaded
Warm start  
Anti-spoofing Accuracy maintained in spoofing environment up to 10db> satellite signals
Jamming Operates with 34dB J/S at both L1 and L2
Cold Start Requirement Automatic. No input of time or position
CV Fill compatibility Via KYK-13
Timing Accuracy  
Tracking satellites ±100 ns. Absolute UTC
  Std Deviation 20 ns
Holdover Mode One microsecond/day
Frequency Stability  
Tracking satellites See table below
Holdover Mode  
Aging <5x10-11/month after 30 days aging
Temperature ± 1x10-10 0 to 50°C
Ethernet Interface        
Type 10BaseT (100 base T optional)        
Connector RJ45        
Protocols Supported NTP (RFC1305), SNTP, Daytime        
Web Browser 5 pages        
  Status, GPS, Configuration, Alarms, Charts        
IP selection Static or Dynamic via DHCP        
Protocols Daytime, Telnet, FTP, DHCP, Time        
Other products        
FTSU-100 Frequency Synthesizer Distribution Amplifier        
Time/message display        
Video Time/message inserters        
Timing plug ins for CPCI, PCI, PC104, VME, PMC and ISA platforms        
Time and Frequency distribution        


Available upon request.


About Brandywine Communications

Brandywine Communications Inc. offers superior products to the time and frequency marketplace. Our mission is to provide the finest equipment coupled with excellent before and after sale service.

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Brandywine Communications
Ultra-Precision Time & Frequency

1153 Warner Ave
Tustin, CA 92780
Phone: +1 (714) 755-1050