PTU
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 synchronised 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 Number | Description | Oscillator Type | Power Supply | Form Factor | Power Type | Output Format | Input Format |
|---|---|---|---|---|---|---|---|
| PTU-OCXO | Portable Timing Unit - OCXO Oscillator Option | OCXO | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-RB | Portable Timing Unit Rubidium Oscillator Option - GPS Input Option | Rubidium | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-TCXO | Portable Timing Unit TCXO - GPS Input Option | TCXO | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-RB-28VDC | Portable Timing Unit Rubidium Oscillator Option 28VDC | Rubidium | Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-RB-115VAC | Portable Timing Unit Rubidium Oscillator Option 115VAC | Rubidium | Single AC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-OCXO-HQ | PTU, OCXO Oscillator Option, HI-Z Have Quick Input | OCXO | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-OCXO | Portable Timing Unit with OCXO Oscillator Option | OCXO | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-OCXO-IRIG | Portable Timing Unit OCXO Oscillator Option - GPS Input Option W/ IRIG | OCXO | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
| PTU-100E | Portable Timing Unit - 100BaseT Ethernet Version | Rubidium | Single AC, Single DC, Internal Li-Ion Battery | 6" x 8" x 12" | AC, DC, Battery | 1PPS, IRIG, Have Quick, RS232 | GPS, Have Quick/1PPS, IRIG |
Features
Reference Input Sources
The PTU is extremely flexible in its ability to synchronise 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 synchronised 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 synchronisation, 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 |
