Design and Design and Fabrication of a Q-Fabrication of a Q-BPM Calibration Tone BPM Calibration Tone
Generator for the Generator for the ATF2ATF2
Ian BullockIan Bullock
August 14, 2008August 14, 2008
ATF2ATF2
Q-BPMsQ-BPMs
Cavity BPMs attached to quadrupole magnetsCavity BPMs attached to quadrupole magnets Give 6426 MHz signal downmixed to 20 MHzGive 6426 MHz signal downmixed to 20 MHz 20 MHz signal is then digitized and analyzed to 20 MHz signal is then digitized and analyzed to
determine beam position to better than 100 nmdetermine beam position to better than 100 nm
Need for a Calibration Need for a Calibration ToneTone
Downmix boards have variable gainDownmix boards have variable gain Gain must be calibrated to precisely Gain must be calibrated to precisely
determine electron bunch displacementdetermine electron bunch displacement
Calibration Tone DesignCalibration Tone Design
714 MHz input from master oscillator714 MHz input from master oscillator TTL logic input to control when output is onTTL logic input to control when output is on 6426 MHz output similar in frequency to signal 6426 MHz output similar in frequency to signal
obtained from a passing electron bunchobtained from a passing electron bunch
Calibration Tone Calibration Tone RequirementsRequirements
10 dBm 714 MHz input 10 dBm 714 MHz input 25 dBm 6426 MHz output25 dBm 6426 MHz output High switch isolation High switch isolation Low noise floorLow noise floor Spectrally pure outputSpectrally pure output
Calibration Tone Design Calibration Tone Design
SMA Connector DesignSMA Connector Design
RF SwitchRF Switch
FinalFinalBPFBPF
TriplerTripler
DoublerDoubler
SplitterSplitter
MixerMixer
AmpAmp
AmpAmp
HPFHPF LPFLPF 6426 6426 MHzMHzOutOut
714714MHzMHzInIn
TTL InTTL In
LPFLPF
SMA Design OutputSMA Design Output
SMA Switching SMA Switching PerformancePerformancePower Measured from Downmix Power Measured from Downmix Board at Board at
20 MHz20 MHz 40 MHz40 MHz 6426 MHz6426 MHz
Switch Switch on:on: 11 dBm11 dBm -43 dBm-43 dBm -81 dBm-81 dBm
Switch Switch off: off: -80 dBm-80 dBm -100 dBm-100 dBm -100 dBm-100 dBm
PCB DesignPCB Design
ConclusionsConclusions
6426 MHz output acceptable6426 MHz output acceptable Switch isolation also sufficientSwitch isolation also sufficient
PCB design still to be testedPCB design still to be tested Final amplifier neededFinal amplifier needed Installation in chassis requiredInstallation in chassis required
AcknowledgementsAcknowledgements
Doug McCormickDoug McCormick Steve Rock, Susan Schultz, Farah Steve Rock, Susan Schultz, Farah
RahbarRahbar SLAC, SULI, DOESLAC, SULI, DOE
Top Related