Undersampling based IQ demodulator for particle accelerator cavities: design, implementation and characterization
This work details the development and validation of a high-precision, cost-effective undersampling-based IQ demodulation system for high-frequency RF signals, designed for particle accelerator cavity control. Theoretical modeling of Track-and-Hold Amplifiers (THAs) revealed that clock phase noise si...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad del País Vasco |
| Repositorio: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/75436 |
| Acceso en línea: | http://hdl.handle.net/10810/75436 |
| Access Level: | acceso abierto |
| Palabra clave: | Radio Frequency (RF) subsampling IQ/ modulation/demodulation Track-and-Hold Amplifiers (THA) magnetrons |
| Sumario: | This work details the development and validation of a high-precision, cost-effective undersampling-based IQ demodulation system for high-frequency RF signals, designed for particle accelerator cavity control. Theoretical modeling of Track-and-Hold Amplifiers (THAs) revealed that clock phase noise significantly impacts measurement accuracy, with an order of magnitude increase in jitter or signal frequency leading to a two-order-of-magnitude rise in output noise. An analytical study also informed compensation strategies for ”quadrature oscillations” arising from small deviations between the modulation and demodulation frequencies (further confirmed in simulations and experimentally). A prototype, built on the NI FlexRIO PXIe platform with a 14-bit, 250 MS/s ADC, incorporates an FPGA-based Tayloe detector featuring a pipelined CORDIC algorithm and real-time THA non-linearity correction. Experimental validation confirmed accurate demodulation and oscillation mitigation across several Nyquist Zones. Its successful application to a magnetron signal demonstrated robust capture of complex amplitude and phase dynamics, highlighting its potential for Low-Level RF control in accelerators |
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