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GPS-4 Time and Frequency Standard |
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The GPS4 is a time and frequency standards that offers high stability outputs synchronized to GPS and packaged in a compact chassis. Often specified outputs such as 1PPS, 10MHz, sine, two serial ports and IRIG B are a standard in this unit. Synthesized frequencies of 19.6608MHz, 2.048MHz and 1.544MHz are also available. The GPS4 also has exceptional holdover performance on the 10MHz sine wave. Status indicators and hardware status & control lines complete the feature list of this economical time and frequency instrument.
- GPS synchronization
- Low cost
- Time code output
- Two serial ports
- 10 MHz output
| 1 PPS Output |
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| Connector |
BNC |
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| Type |
TTL into 50 Ohms |
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| On Time Edge |
Rising edge |
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| Serial Interface |
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| Number of Ports |
2 |
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| Connector |
DB9 |
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| Type |
RS-232 or RS-422 (option) |
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| Baud Rate |
50-19,200 |
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| Time Port |
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| Data |
Time and Date |
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| Message Rate |
1PPS Continuous |
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| Control Port |
System set up and control |
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| IRIG B Time CCCCCode |
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| Carrier Frequency |
1kHz |
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| Data |
Seconds through Days |
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| Amplitude |
3Vpp into 600 Ohms |
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| Modulation Ratio |
3.3 to 1 |
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| Connector |
BNC |
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| Environmental |
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| Temperature |
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| Instrument |
-10°C to +60°C (DT 15°C per hour) |
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| Antenna |
-40 to +85°C |
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| Humidity |
To 95% non-condensing |
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| Power |
15 Vdc |
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| Optional |
24 Vdc, -48 Vdc |
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| Dimensions |
5.8” x 5.5” x 1.5” |
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| Weight |
3lb typical |
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| EMC Emission |
To EN50081-1 as EN55022 |
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| EMC Immunity |
To EN50082-1 as EN1000-4-2 ESD, |
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IEC 801-3 HF Field, IEC 801-4 Burst |
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| 10MHz Sine Wave Output |
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| Connector |
BNC |
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| Level |
1 Vrms into 50 Ohms |
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| Accuracy |
5x10-12/24 hours when locked |
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| Holdover |
1x10-10/24 hours average |
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| Phase Noise |
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| 100Hz |
-140dBc/Hz |
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| 1000Hz |
-150dBc/Hz |
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| 10000Hz |
-155dBc/Hz |
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| Stability |
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| 1Sec |
1x10-11 |
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| 10Sec |
1x10-11 |
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| 100Sec |
8x10-12 |
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| 1000Sec |
1x10-11 |
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| GPS Specifications |
| Satellite Signal |
GPS L1 1575.42 MHz |
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| Satellite Code |
C/A 1.023 Mhz |
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| Receiver Type |
Parallel 8 Channel, 8 Satellites tracked |
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continuously and simultaneously |
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| Position Accuracy |
2.4m horizontal, 5m altitude with |
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position averaging |
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| Warm start |
<20 seconds |
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| Autonomous Start |
<120 seconds |
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| Cold Start Requirement |
Automatic. No input of time or position |
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required |
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| Timing Accuracy |
| Tracking satellites |
±100 ns. Absolute UTC Std Deviation |
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34 ns. Hourly mean 25 ns |
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| Holdover Mode |
<8 µsec/8 hours |
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| Synthesizer Outputs |
| Frequencies |
19.9608MHz, 1.544MHz, 2.048MHz |
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| Accuracy |
Same as 10MHz |
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| Amplitude |
TTL into 50 Ohms |
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| Connector |
BNC |
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| Status Indicators |
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| Power Good |
Flashes when out of tolerance |
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| Locked |
Illuminated to system locked to GPS |
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| Holdover Mode |
GPS input lost, making corrections to or |
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osc. based on learned information |
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| Alarm |
Illuminated when: |
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a. Internal GPS receiver fault |
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b. System Power Failure |
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c. PLL out of lock |
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| Hardware Status/Control Lines |
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| Connector |
DB-9 |
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| Levels |
Open Collector |
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| Max Pull up Voltage |
+5Vdc |
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| Sink Current |
30ma |
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| Status bit 1 |
/Time Lock |
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| Status bit 2 |
/System good |
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| Reset Input |
/System Reset Input |
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| Options |
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| IRIG B DC Shift |
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GPS-4 Data Sheet