• J. Ning, C.-Y. Tan
  Fermilab, Batavia, Illinois

We build an electronical instrument to get the frequency response close to the pattern of transverse beam frequency response. The method is to apply 1)a time delay circuit with ADC, FIFO RAM and DAC; 2)a phase shift circuit which is an all pass filter with adjustable phase shift in the frequency range of 25kHz to 30kHz; in a feedback loop of 3)a commutating filter which is a high Q band pass filter. We can dynamically adjust the center frequency, the side band distance during the testing. With this instrument, some beam instruments can be tested without using the real beam.