Re: [Discuss-gnuradio] Half-Band Filter Module Output Clipping?

[Matt Ettus]

Bruce McGuffin wrote:
> > Based on the coefficients, we can guarantee that the final sum will 
> > have a magnitude which fits in 20 bits, including the sign bit.  We 
> > can just drop those extra sign bits, since they'll all be the same.
> >
> > Matt
> >   
> So I'm curious. If the final sum fit into 20 bits, why were the 
> accumulation and
> following sum carried out with 24 or 25 bits?
>
> Bruce

If we changed the coefficients we might need more bits.

Matt