December 2019: Frequency Beating in RRF Supply Room

Table of Contents

Setup

In December 2019 measurements have been done using the following setup in the RRF supply room in building BG.

• two 'DDS h=1 signals' generated using two real DDS H=1 systems
• two timing receivers for phase measurements (pexaria, lm32 firmware); one TR per signal
• one timing receiver as cbu (pexaria, lm32 firmware)
• one timine reciever for generating a 'synch signal' (pexaria, config via 'saft tools')

The timing receiver have been connected to a White Rabbit network.

The 200 MHz input clock of the two DDS systems has been supplied by BuTiS.

BuTiS and White Rabbit are phase locked to each other by using a GPSDO as common reference clock.

The following parameters have been used

• https://github.com/GSI-CS-CO/bel_projects
  • branch b2b_dietrich_2019-11-05
  • commit 22a63fe
  • /modules/b2b-test/
• typical frequencies of ~1 MHz
• beating periods up to 100ms

Measurements

Figure: Measurements performed with 'real' DDS systems.

The figure above shows measurements performed with the real DDS hardware of SIS18 and ESR at BG1 (on 23 December 2019 ). The DDS systems receive their reference clocks from BuTiS. White Rabbit and BuTiS are phase locked to each other. The precision achieved for phase matching is ~1.5ns.

-- DietrichBeck - 27 Nov 2020