6 Introduction

The Median Filter is a nonlinear digital filtering technique, often used to remove glitches from an analog signal.

The Median Filter is used to remove the noise from a signal. It forms a window of N (this IP supports N = 5, 7, and 9) adjacent samples and finds the median of these samples.

Examples:

  • If N = 9 and {15, 13, 25, 18, 35, 46, 61, 26, 9} is a set of input samples, then median is 25
  • If N = 7 and {12, 11, 27, 19, 9, 6, 3} is a set of input samples, then median is 11
  • If N = 5 and {15, 15, 12, 11, 10} is a set of input samples, then median is 12

Summary

The following table provides a summary of the Median filter characteristics.

Table 6-1. Median Filter Characteristics
Core VersionThis document applies to Median Filter v4.2.
Supported Device Families
  • PolarFire® SoC
  • PolarFire
  • RTG4™
  • IGLOO® 2
  • SmartFusion® 2
Supported Tool FlowRequires Libero® SoC v11.8 or later releases.
LicensingComplete encrypted RTL code is provided for the core, enabling the core to be instantiated with SmartDesign. Simulation, Synthesis, and Layout are performed with Libero software. Median Filter is licensed with encrypted RTL that must be purchased separately. For more information, see Median Filter.

Features

Median Filter has the following key features:

  • Finds the median of a set of input samples
  • Window sizes are adjustable (5, 7, and 9)

Implementation of IP Core in Libero Design Suite

IP core must be installed to the IP Catalog of the Libero SoC software. This is done automatically through the IP Catalog update function in the Libero SoC software, or the IP core is manually downloaded from the catalog. Once the IP core is installed in the Libero SoC software IP Catalog, the core is configured, generated, and instantiated within the SmartDesign tool for inclusion in the Libero project list.