This might be a silly question. But here goes …
In gr_fractional_interpolator_ff I observed that to make the filter
interpolate between input values you have to set the interpolation ratio
and this is because the block has this line in the code
(1.0 / interp_ratio)”. I always thought for a block named interpolator a
value of interpolation_ratio > 1 would be understood as increasing the
sampling rate by that factor. Is this not correct?