Motorola M12 Oncore User's Guide download pdf (Page 21)

Chapter 3 – Receiver Description

Motorola GPS Products - Oncore User’s Guide

100PPS OUTPUT (UT MODEL ONLY)

With the UT Oncore 2.x firmware, the timing output can be selected between 1PPS

and 100PPS. This is done using the Pulse Mode command (@@AP). See chapter 6 for

information on the format of this command.

When selected, the 100PPS signal is output on the same pin as the 1PPS. The 100PPS

signal has the same accuracy and stability characteristics as the 1PPS signal. Each

pulse is approximately 2-3 ms in duration (the pulse width is not accurately

controlled) so the 100PPS signal has a nominal duty cycle of approximately 25%.

Every hundredth pulse is 6-7 ms in duration. The leading edge of the pulse following

the long pulse corresponds to the top of the second (UTC or GPS, depending on the

Time Mode). Figure 3.7 shows a diagram of the 100PPS output signal.

The 1PPS Offset and 1PPS Cable Delay features work the same in 100PPS mode as

they do in 1PPS mode. In 100PPS mode, these commands are used to accurately

control the placement of the pulse after the long pulse.

Figure 3.7

Revision 5.0 08/30/02

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Motorola M12 Oncore User's Guide Page 21