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Grand Master Source

Project description

When operating White Rabbit switches as time transmitter (mode master) the timing relies on the quality of the White Rabbit switch local oscillator.
If White Rabbit time receivers are connected that have a high quality local oscillator is can happen that the quality of the local oscillator of the WR switch in time transmitter master mode is not sufficient. The WR switch local oscillator center frequency might even be outside the frequency tuning range of the high quality oscillator of the WR time receiver.

The WR switch is therefor usually operated in Grand Master mode. However, a GPS source or Waveform generator (like Agilent 33600A) is not always available to source the WR switch with a 10 MHz and 1PPS signal. This is where the Grand Master Source project will be an easy and cheap solution based on a SiTime 10MHz TCXO (SIT5155).
Figure 1 shows a picture of a Grand Master Source and Figure 2 shows the open box.

Figure 1: Grand Master Source

Figure 2: The internals of the Grand Master Source

Performance:

Figure 3: The phase noise performance (-107dBc/Hz @ 10Hz offset) and spectrum of the 10MHz output signal.

Flash Programming

Unfortunately the Xilinx download cable connector pinout was messed up (see issue 1311). Connect the flying wires according to the Figure 4 below:

Figure 4: Connecting the Xilinx Programming Cable with flying leads.

In Vivado Hardware Manager, Add Configuration Memory Device "mt25gl128-spi-x1_x2_x4" (Micron 128 Mb flash), see figure 5.

Figure 5: FLASH programming.

Precompiled files:

.mcs
.bit

Design details

Issues

  • Xilinx download cable connector pinout messed up (issue 1311)
  • Schematics and Manufacturing files contain wrong (i.e. voltage controlled) oscillator part number. U13 must be SIT5155AI-FK-33E0-10.000000 (issue 1349)

Contacts

General questions about project

Status

Date Event
29-11-2023 Initial wiki.

8 March 2024

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