filter realization help

[maduba]

I need a help with filter realization. I dont understand how this works. This is a multiply and accumulate filter, I dont understand why cof[0] constant is multiplied, here is the code cof is the filter coefficients and sample is the samples. Any help with this very appreciated. Thank you

 

[Ian Rogers]

cof is a pointer to an array of different constants. sample is multiplied by the appropriate one.. cof[x] is indexing that array.

 

[maduba]

thank you for the reply. I also dont understand why item /= 4 used?

 

[Ian Rogers]

No Idea... Possibly there are multiple items per constant...

 

[maduba]

Thank you for the reply. This is a decimating filter. Thank you very much about the explanation about cof[0].It is clear for me. I have a another question. This is also part of code and related. I dont understand how this works. I dont understand why mac function called twice.