PTU

Network Ready Portable Timing Unit

The Portable Timing Unit (PTU) is a 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 including SAASM GPS, or by a serial time code such as IRIG B or Have Quick. Outputs include: NTP, IRIG A, IRIG B, IRIG G, Have Quick, and 1PPS. A range of options are available for the oscillator which include: Rubidium, OCXO, or TCXO. Built in a rugged, weather-proof case the PTU is easily transportable to any location and can be used in all weather conditions to give precise Time and Frequency.

Variations

Model NumberDescriptionOscillator TypePower SupplyForm FactorPower TypeOutput FormatInput Format
PTU-OCXOPortable Timing Unit - OCXO Oscillator OptionOCXOSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-RBPortable Timing Unit Rubidium Oscillator Option - GPS Input OptionRubidiumSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-TCXOPortable Timing Unit TCXO - GPS Input OptionTCXOSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-RB-28VDCPortable Timing Unit Rubidium Oscillator Option 28VDCRubidiumSingle DC, Internal Li-Ion Battery6" x 8" x 12"DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-RB-115VACPortable Timing Unit Rubidium Oscillator Option 115VACRubidiumSingle AC, Internal Li-Ion Battery6" x 8" x 12"AC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-OCXO-HQPTU, OCXO Oscillator Option, HI-Z Have Quick InputOCXOSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-OCXOPortable Timing Unit with OCXO Oscillator OptionOCXOSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-OCXO-IRIGPortable Timing Unit OCXO Oscillator Option - GPS Input Option W/ IRIGOCXOSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG
PTU-100EPortable Timing Unit - 100BaseT Ethernet VersionRubidiumSingle AC, Single DC, Internal Li-Ion Battery6" x 8" x 12"AC, DC, Battery1PPS, IRIG, Have Quick, RS232GPS, Have Quick/1PPS, IRIG

Features

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

A high precision oscillator maintains the internal time of the PTU. 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

Internal Battery Backup

The PTU contains an internal 7Ah battery that will operate the system in the event prime power is lost. The battery charge is monitored and maintained whenever prime power is applied to the PTU. Status is indicated by front panel LED’s. Battery life is dependent upon the oscillator configuration selected and the ambient temperature, but 5 hours is typical for the OCXO version.

Time Display

An 11-digit display indicates Years, Days, Hours, Minutes and Seconds. A front panel switch controls the illumination of the display to conserve battery life.

External Event Input

The PTU includes an external event input that will latch the time of external events applied as pulses to this input. The time tags are stored in an internal memory and may be displayed and retrieved using the network interface.

Weatherproof Enclosure

The PTU is housed in a sturdy weatherproof enclosure that is suitable for outdoor use in all weather conditions.

Specifications

GPS Receiver
Satellite Signal GPS L1 1575.42 MHz
Satellite Code C/A 1.023 MHz
Receiver Type Parallel 16-Channel. All-in-view satellites tracked continuously and simultaneously.
Warm Start <10 sec (Open Sky)
Autonomous Start <60 seconds Cold Start (Open Sky)
Cold Start Requirements Automatic: No input of time or position required
Position Accuracy 2.4 m horizontal, 5 m altitude with respect to WGS84 after 24 hour position averaging
Timing Accuracy (Tracking Satellites) +/- 50 ns. absolute UTC, Std Deviation 15ns (OCXO)
Timing Accuracy (Holdover mode, +/- 5°C) < 20ms/day (TCXO), < 50 usec/day (OCXO), < 5 usec /day (Rb)
1PPS Output
Connector Type BNC
Output Level 0-5V or 0-10V into 50 ohms link selectable by user
On Time Rising Edge
Network Interface
Interface Type 10BaseT
Network Protocols TCP/IP, UDP, NTPv3, HTTP, SNMP v1, DHCP
Serial Interface
Interface Type RS232
Baud Rate 9600, N, 8, 1
Content User configurable, broadcast 1/sec
IRIG Time Code Output
Connector Type BNC
Code Type B125, standard IRIG A135, E115, G145 optional
Control Functions IEEE 1344
Output Level 3 Vpp into 600 ohm
Have Quick Output
Connector Type BNC
Code Type Have Quick II per ICD-GPS-060
Levels 0-5V
Alarm Status
Alarm Status Voltage free relay changeover contacts
Status Indicator LEDs
Status Indicator LED's Power, GPS Locked, Time Valid, IRIG, Have Quick, Fault, Battery Charge, Battery Low
1PPS Input
Connector Type BNC
Input Level 2.5V to 5V
Input Impedance 50 ohms
Have Quick Input
Connector Type BNC
Code Type Have Quick II per ICD-GPS-060
IRIG Time Code Input
Connector Type BNC
Code Type B120, B122, B123, B125
Control Functions IEEE 1344 supported
Input Impedance 600 ohm
Input Level 1-6 Vpp
External Event Input
Trigger Rising Edge triggered
Isolation Optical
Input Impedance 5K
Max no. of Event Last 100 events are stored
Max Repetition Rate > 500 usec between events
Battery
Battery Life at 25 +/- 15 deg. C 24 hours (TCXO), 5 hours (OCXO), 3 hours (Rb)
Battery Charging Temperature -20 deg. C to 50 deg. C
Environmental
Temperature Instrument: -40 to +60 deg. C, Rb1 Option: -10 to +50 deg. C, Rb2 Option: -20 to +60 deg. C
Humidity 95%
Sealing IP54, NEMA 3
Power 85-265VAC 50/60Hz, 12VDC
EMC Emmission EN55022, FCC Chapter 15 Part B
EMC Immunity EN55024
Physical
Dimensions 6" Wide, 8" High, 12" Deep
Weight 11 lb. Typical

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