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Timing & Frequency

Brandywine GPS Airborne Approved PTS-SAASM Network Ready Master Clock
Product Overview
  • GSP 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


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.

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.

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

Specifications & Detail
PPS Output
Connector SMA
Type 5V0-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) <-130 dBc/Hz (10Hz) typical
<-140 dBc/Hz (100Hz) typical
<-150 dBc/Hz (1000 Hz) typical
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
P(Y) Code GPS Receiver Specification Option)
Receiver Type GRAM SA-ASM receiver
Satellite Signal GPS L1, L2Dual 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 <120 seconds with Almanac, CV loaded
Anti-spoofing Accuracy maintained in spoofing environment up to 10db> satellite signals
Jamming Operates with 34dB J/S at both L1and 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 ± 1x10-100 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

Data Sheet & Downloads