Chen, F.Z. Chen, J. Lai, L.W. Leng, Y.B. Wu, T. Yu, L.Y. Yuan, R.X. JACoW Publishing Geneva, Switzerland 978-3-95450-201-1 10.18429/JACoW-IBIC2018-MOPC17 English 150-153 MOPC17 FEL cavity experiment undulator background Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-IBIC2018-MOPC17 http://jacow.org/ibic2018/papers/mopc17.pdf Shanghai soft X-ray Free Electron Laser (SXFEL) has acquired the custom designed Digital BPM processor used for signal processing of cavity BPMs and stripline BPMs. In order to realize monitor the beam position accurately, it has high demand for DBPM system performance. Considering the crosstalk may introduce distortion and influence beam position resolution, it is important to analyze and compensate the crosstalk to improve the resolution. We choose the CBPM signal to study the crosstalk for its narrowband and sensitive for phase. The main experiment concept is successive accessing four channels to form a signal transfer matrix, which including amplitude frequency response and phase response information. And the compensation algorithm is acquire four channel readouts, then using the signal transfer matrix to reverse the true signal to ensure the accurate beam position measurement. This concept has already been tested at SXFEL and hopeful to compensate the crosstalk sufficiently.