Brandywine Portable Timing Unit, User Manual, Page: 5 / 31

MANUAL P/N 900000118 REV D
5
1 Introduction
The Portable Timing Unit (PTU) is low cost, battery operated, transportable timing
system that is designed to provide precise time of day at point of use. The PTU may
be automatically synchronized by means of either GPS signals, or an serial time code
such as IRIG B or Have Quick.
Operation of the unit can be monitored via an Ethernet interface, or by means of
front panel indicators and displays. Outputs are 1PPS, Have Quick, IRIG B Time Code
and Network Time Protocol (NTP).
The unit is mounted in a rugged, weather proof case that may be easily transported
to the point of use. When AC power is available, the PTU’s built-in power supply will
automatically charge the internal batteries.
Reference Input Sources
The PTU is extremely flexible in its ability to synchronize to a variety of timing
sources. Available references are:
•
16 channel GPS SPS receiver (standard)
•
12 channel GB-GRAM SAASM GPS receiver (optional)
•
IRIG B Time Code (standard)
•
HaveQuick/1PPS from external GPS receiver (standard)
Once synchronized to the selected reference, the PTU will use the reference to
continuously calibrate its internal oscillator so that accurate time can be maintained
in the absence the reference. Front panel LEDs indicate the reference type in use,
and whether time is valid. The PTU can be configured to always use a particular
reference source, or automatically select whatever source is available.
Time Keeping
The internal time of the PTU is maintained by a high precision oscillator. Selection of
the oscillator type will determine the accuracy of the PTU when its reference, (such
as GPS) is not available. Available internal oscillator options are
•
Temperature Compensated Crystal Oscillator (TCXO) -option
•
Oven Controlled Crystal Oscillator (OCXO) standard
•
Atomic Rubidium Oscillator – option
Network Interface
The PTU incorporates an Ethernet connection that provides a convenient means of
monitoring status of the instrument via a computer and simple web browser. This
interface is also used to provide NTP synchronization, firmware updates and
Browser based setup features.
Output Signals
The PTU provides a variety of timing signal outputs, giving maximum application
flexibility
•
1PPS 1 Pulse Per Second Signal Time Mark
•
Have Quick Time Code
•
IRIG B Time Code
•
NTP