Timing and Synchronization @ NML

1
Timing and Synchronization _at_ NML

• B. Chase
• 7/12/07

2
Time Standards

• There are two natural time metrics at NML
• NIST time which we can receive via GPS
• RF time based on the 1300 MHz Master Oscillator
  and a start trigger
• There is one unnatural time-base
• Power line based 60 Hz
• Power line synchronization is needed to alias out
  line harmonics in accelerator systems by beam
• Variability in power line frequency breaks the
  NIST and RF relationship

3
Suggested Time Metrics

• GPS time for non beam related sampling
• As good as 10ns accuracy and max resolution for
  SOME systems. As bad as 10 us for others
• Record the time for each start trigger (T0)
• RF time-base for the RF cycle
• Sub 100 fs accuracy and resolution
• This can be translated to seconds for non beam
  information (ie RF waveforms)
• For beam data the bunch number is used as an
  index
• Time, RF cycle (event delay), RF cycle(bunch)

4
Data Correlation

• Requirements
• An accurate meter stick clock lattice
• A time stamp model that supports the clock
  lattice (hardware and software)
• Analysis software that supports the multiple time
  base issue and will also support the multiple
  clock rates used in data acquisition

5
Clock Source Synchronization

• Various clocks used for DAQ and control must be
  aligned at T0 (start of RF process) synchronous
  with 60 Hz
• Master Oscillator RF_at_ 1300MHz,, Laser _at_ 81.25MHz,
  Controls clk _at_ 9.027778MHz, beam _at_ 81.25/n MHz,
  other?
• The LLRF LO _at_ 1313MHz will probably not be
  synchronized, LLRF clock _at_ LO/21

6
Sources of Clean RF

• Master Oscillator
• Main source but is only at one location
• RF Reference line
• Mostly for LLRF
• Very limited use for VERY good reasons
• Local Oscillator
• Mostly for LLRF
• Others can use for good reasons
• Control clock (9.02777MHz)
• Can be used with PLL or as is
• Guessing much higher jitter