Matlab generated code. Embedded implementation

Hello. I try to realize Cheby1 filter in embedded system ( stm32 based ). For this i get logs from microcontroller - there is blue line in graph. So there is noised raw data. Then i realize Cheby1 filter in Matlab and it work good - green line in graph. After that i generate C code using Matlab coder and move it in firmware for microcontroller as is. And there is result - red line in graph - it is gain cutted! What is the reason of it? Where am i mistaken?