  The primary purpose of the Fermilab Recycler Ring Transverse Digital Damper
System is to prevent instabilities due to high phase space densities of the
cooled antiproton beam. The system was designed to facilitate Beam Transfer
Function measurements using a signal analyzer connected to auxiliary system
ports for timing and diagnostic purposes. The Digital Damper System has the
capability for both open and closed loop measurements. The Beam Transfer
Function provides direct measurement of the machine impedance, and beam and
lattice parameters such as betatron tune and chromaticity. An overview of the
technique is presented along with analysis and results from open and closed
loop measurements in the Fermilab Recycler Ring.
