User`s manual

Page 1
1 Overview
1.1 Introduction
MicroDAC 5 is the latest generation of DAC's most popular tactical digital
adaptive filter. The MicroDAC 5 is designed to complement your tactical
surveillance efforts, packaging the most commonly used filters in a powerful and
easy-to-operate unit.
MicroDAC 5 contains four different filters for removing common noise problems
in surveillance audio. The four filters are:
 A Multi-Channel Adaptive filter. This filter can be used as a reference
canceller to remove up to three reference signals. This filter can also be
configured as a one-channel adaptive filter, or deconvolver, to remove
common noises such as power hum, tones, and echoes.
 A One-Channel adaptive filter. Following the reference canceller, this
second adaptive filter removes any remaining tonal noise or
reverberations.
 A Highpass filter. This filter removes low-frequency rumble that lies below
the range of normal speech.
 An Automatic Gain Control. This filter boosts low-level speech for easier
hearing while leaving unaffected the parts of the signal that are already at
a comfortable listening level.
The MicroDAC 5 is suitable for processing recorded audio or for use in live
listening situations, but it is specifically designed for easy use in a tactical
environment. The unit comes programmed with default settings that are
appropriate for the most common audio situations. The software utility that
accompanies the MicroDAC 5 allows finer control of the filtering behavior of the
unit, and can be used to build a configuration that works best for your recorded
audio or listening environment. Your configuration can then be programmed into
the unit for tactical use.
1.2 Original Factory Configuration
In the factory configuration, the two adaptive filters are always running at default
settings that are appropriate for cancellation of most common noises. Sensible
adaptive filter lengths and delays are chosen. A sensible adapt rate is selected
so that the filter can adapt in reasonable time to most noises without becoming
unstable. Auto-scaling of the adapt rate based on the signal power aids filter