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TFBPICKUP

Pickup for a transverse feedback loop
Parallel capable? : no
Parameter Name Units Type Default Description
ID   STRING NULL System identifier
PLANE   STRING x "x" or "y"
RMS_NOISE $M$ double 0.0 RMS noise to add to position readings.
A0   double 0.0 Filter coefficient
A1   double 0.0 Filter coefficient
A2   double 0.0 Filter coefficient
A3   double 0.0 Filter coefficient
A4   double 0.0 Filter coefficient
A5   double 0.0 Filter coefficient
A6   double 0.0 Filter coefficient
A7   double 0.0 Filter coefficient
A8   double 0.0 Filter coefficient
A9   double 0.0 Filter coefficient
A10   double 0.0 Filter coefficient
A11   double 0.0 Filter coefficient
A12   double 0.0 Filter coefficient
A13   double 0.0 Filter coefficient
A14   double 0.0 Filter coefficient
GROUP   string NULL Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup





This element is used together with the TFBDRIVER element to simulate a digital transverse feedback system. Each TFBPICKUP element must have a unique identification string assigned to it using the ID parameter. This is used to identify which drivers get signals from the pickup.

A 15-term FIR filter can be defined using the A0 through A14 parameters. The input to the filter is the turn-by-turn beam centroid at the pickup location. The output of the filter is simply $\sum_{i=0}^{14} a_i C_i$, where $C_i$ is the position from $i$ turns ago. Note that $\sum_{i=0}^{14} a_i$ must be zero. Otherwise, the system will attempt to correct the DC orbit. The output of the filter is the input to the driver element(s).

See Section 7.2.14 of Handbook of Accelerator Physics and Engineering (Chao and Tigner, eds.) for a discussion of feedback systems.


next up previous
Next: TMCF Up: Element Dictionary Previous: TFBDRIVER
Robert Soliday 2014-03-21