an aspiring electronics engineer here. I do some electronics design for work and I'd like to know the following:
If I have an assembly of a main board, to which an FFC cable connects into a second board (A), to which another FFC cable connects to a last board. Some signals flow back and forth between these different boards (e.g. I2C), so I'd like to do some low-pass filtering for EMI. From my work I've learned you can put a filter in series close to the connector where the signal 'leaves' one board. Since my signal leaves my Main board, but also board A, does this mean I should put something like a T-filter in the signals in both the Main board and in board A? Or would the two filters -separated by some FFC length and PCB- still function as one filter anyway?
How do I design for EMC here?