UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 15412

LogiCORE DA FIR Filter v.7 - What is zero-packing? Why can I only use zero-packing in interpolation or interpolated modes?

Description

Keywords: zero, pack, DA FIR, filter, interpolation, interpolated

What is zero-packing? Why can I only use zero-packing in interpolation or interpolated modes?

Solution

"Zero-packing" means that zeroes are inserted between the coefficients. A zero-packing of 3 indicates that 3 zeros are inserted between every coefficient; this creates an interpolated filter, which is typically used to create cheaper narrow band filters. However, this is still a single-rate FIR filter.

An interpolation filter zero-packs the data stream, and the zero-packing factor is inferred through the sampling rate change (a rate change of 4 means a zero-stuffing of 3). However, the zero-packing is never actually implemented, and a polyphase structure is used. (This is much more efficient, as multiplying by zero is a waste of logic.)

If you require a sample rate change, use the interpolation filter.
AR# 15412
Date Created 09/03/2007
Last Updated 04/01/2009
Status Archive
Type General Article