Wu, R.Z. Lu, P. Sun, B.G. Tang, L.L. Wang, D.Y. Zhao, Y.K. JACoW Publishing Geneva, Switzerland 2673-5350 978-3-95450-236-3 10.18429/JACoW-IBIC2023-WEP011 English 347-349 storage-ring real-time SRF data-acquisition timing Contribution to a conference proceedings 2023 2023-12 https://doi.org/10.18429/JACoW-IBIC2023-WEP011 https://jacow.org/ibic2023/papers/wep011.pdf The decrease of beam emittance in the 4th generation light source greatly increases the electron density, thus the wakefields and beam impedance in the storage ring are significantly enhanced, resulting in various beam instabilities. Therefore, it is necessary to observe the transient state of beams using the bunch-by-bunch technique, so as to dig into these instabilities. Here a three-dimensional (3D) positions measurement instrument is designed based on data synchronization module (DSM) to acquire the transverse positions and longitudinal phases of beams in real-time.