Thanks for the info. What's the standard to be 11 digits/s? For real 11 digits/s, the ADEV needs to reach the 1e-11 level? I'm not sure if my GPSDO & Rb is stable enough. Maybe 2 MV89A as the refclk and signal? TDC-GP22 has it problem, I will post some data/schematic/source code about it later. Thanks