User`s manual

from a concealed microphone that has interfering radio/TV audio. The RIGHT (REF) input is the

noise reference, usually the audio output from a second radio/TV tuned to the same channel.

The signals are first fed through the stereo Limiter, which helps prevent the signals from distorting

on overload. The Limiter internally “links” the two channels, such that an overload on either input

channel will cause the levels to be reduced equally on both channels. This minimizes the impact on

the 2CH Adaptive filter solution.

The limited signals then enter the first stage 2CH Adaptive filter, which is configured as follows:

Table 4: 2CH MODE First Stage Factory Presets

Parameter Preset Value

Filter Size 3472 taps

Delay Channel Input (Primary)

Delay 100 samples

Adapt Rate 16

Adapt Mode Auto

Output Residue

Algorithm LMS

Reference Compensation Enabled

Crash Detect Enabled

After the first stage of filtering, the signal enters the second stage 1CH Adaptive filter, which is

configured as follows:

Table 5: 2CH MODE Second Stage Factory Presets

Parameter Preset Value

Filter Size 128 taps

Prediction Span Delay 2 samples

Adapt Rate 32

Adapt Mode Auto

Output Residue

Algorithm LMS

Crash Detect Enabled

Next, the signal is 200Hz Highpass filtered, to remove any low frequency noises that may remain

after processing, and 3200Hz Lowpass filtered to remove high frequency hiss.

Finally, a 10dB AGC is applied to correct for near party / far party talkers, and to provide a good

output level for recording.