Interpolated FIR (IFIR) for decimation

1. What is interpolating FIR filter?
2. Why are FIR filters generally preferred over IIR filters in multirate decimating and interpolating systems?

What is interpolating FIR filter?

The FIR Interpolation block upsamples an input by the integer upsampling factor L along the first dimension. The FIR interpolator (as shown in the schematic) conceptually consists of an upsampler followed by an FIR anti-imaging filter, which is usually an approximation of an ideal band-limited interpolation filter.

Why are FIR filters generally preferred over IIR filters in multirate decimating and interpolating systems?

2.4 Why are FIR filters generally preferred over IIR filters in multirate (decimating and interpolating) systems? Because only a fraction of the calculations that would be required to implement a decimating or interpolating FIR in a literal way actually needs to be done.