FINE RESOLUTION PHASE-SHIFTER FOR TPPI IMPLEMENTATION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Implementation of multi-quantum coherence (MQC) requires time delays and phase advances in small steps. Whereas we can produce very accurate timing using specialized ECL modules, accurate phase incrementing is a formidable task. To address this issue we procured a 6-20 GHz 12-bit phase shifter which we will use in our initial MQC work that relies on uniform spectrum excitation. A hardware control will be based on USB interfaced FPGA modules, which we already have. Phase cycle tables and look-up tables will be downloaded via USB and the unit will be controlled in real time using pulse sequence and phase advance/reset signal lines from the system DSP real-time controller. This will enable us to implement Time-Proportional Phase Incrementation (TPPI) for the MQC work.