DS-GPS-CLOCK
TECHNICAL REFERENCE MANUAL
4.1. GPS based operation
The base of any GPS receiver is precise time measurement. In addition to the position information a
precise PPS (pulse per second) is generated by the GPS engine. This pulse is used to synchronize a 40
MHz oscillator with software PLL (phase locked loop). The result is an ultra-stable 40 MHz clock source
which is completely free of drift over time.
Out of this 40 MHz base clock, the programmable clock divider generates the clock frequency for the
standard data acquisition system which is being output on the 9-pin DSUB connector or 4-pin Lemo
connector.
4.2. IRIG based operation
The IRIG signal contains the binary-coded time (year, day of year, hours, minutes, seconds, fractions of a
second) modulated on a sine wave carrier. This signal is decoded to the PPS and the drift-free 40 MHz
clock.
The following IRIG time codes are supported:
●
IRIG-A (10 Hz)
●
IRIG-B (1 Hz)
4.3. LED Description
4.3.1. Power
The power LED is solid green when the DS-GPS-CLOCK is in normal operation.
Image 2: LED lights
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