Linear Interpolation

Now that we’ve finished our series on how to build an upsampling linear interpolator, let’s take a moment to collect the various posts in the series together.

First, we had a pre-series post, discussing how to resample using a sample and hold interperolator.

Given that context, our discussion of how to build a linear interpolator included posts on:

• How an upsampling linear interpolator works

• Bit-width allocation within an FPGA

• How to drop bits (i.e. round), to keep bit growth from getting out of hand

• How to debug DSP logic

The one topic in linear interpolation that wasn’t covered was how to build a downsampling linear interpolator. This hardly needs a discussion of its own, however, since a downsampler that downsamples by an integer amount can easily just select points at the output of the linear upsampler.

Hence, the posts above really cover the issue.