Effect of Numerically Controlled Oscillator Bit Width in Phase Meters

Fuente: arXiv
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Autori principali: Jiang, Yuan-Ze, Feng, Yu-Jie, Chen, Liu-Yang, Lu, Bai-Fu, Xia, Qi, Zhou, Ze-Bing, Liang, Yu-Rong
Natura: Preprint
Pubblicazione: 2025
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author Jiang, Yuan-Ze
Feng, Yu-Jie
Chen, Liu-Yang
Lu, Bai-Fu
Xia, Qi
Zhou, Ze-Bing
Liang, Yu-Rong
author_facet Jiang, Yuan-Ze
Feng, Yu-Jie
Chen, Liu-Yang
Lu, Bai-Fu
Xia, Qi
Zhou, Ze-Bing
Liang, Yu-Rong
contents Projects aiming to detect gravitational waves (GWs) in space in the millihertz range will utilize interferometers to measure the separations between free-falling test masses. The phasemeter measures the phase changes of the interference signals caused by the test masses' relative movements. The measurement sensitivity of the phasemeter is one of the key factors in the detection. In this work, we reviewed the core metrology of the phasemeter and evaluated the ultra-low noise performance of the phasemeter with analog signals. Frequency readout noise related to the bit width of the numerically controlled oscillator (NCO) inside the phasemeter is identified as one of the main noise sources of phase measurement theoretically and experimentally. After increasing the NCO bit widths, the single-channel phase noise of the phasemeter reached 2.0 μrad/Hz^{1/2} at 6 mHz, and the differential phase noise reached 0.4 μrad/Hz^{1/2} at 6 mHz. The phase noise performances remained consistent within the carrier frequency range of 4.9 MHz to 25.1 MHz.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11608
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Effect of Numerically Controlled Oscillator Bit Width in Phase Meters
Jiang, Yuan-Ze
Feng, Yu-Jie
Chen, Liu-Yang
Lu, Bai-Fu
Xia, Qi
Zhou, Ze-Bing
Liang, Yu-Rong
Instrumentation and Methods for Astrophysics
Projects aiming to detect gravitational waves (GWs) in space in the millihertz range will utilize interferometers to measure the separations between free-falling test masses. The phasemeter measures the phase changes of the interference signals caused by the test masses' relative movements. The measurement sensitivity of the phasemeter is one of the key factors in the detection. In this work, we reviewed the core metrology of the phasemeter and evaluated the ultra-low noise performance of the phasemeter with analog signals. Frequency readout noise related to the bit width of the numerically controlled oscillator (NCO) inside the phasemeter is identified as one of the main noise sources of phase measurement theoretically and experimentally. After increasing the NCO bit widths, the single-channel phase noise of the phasemeter reached 2.0 μrad/Hz^{1/2} at 6 mHz, and the differential phase noise reached 0.4 μrad/Hz^{1/2} at 6 mHz. The phase noise performances remained consistent within the carrier frequency range of 4.9 MHz to 25.1 MHz.
title Effect of Numerically Controlled Oscillator Bit Width in Phase Meters
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2502.11608