1020 Spring City Drive, Waukesha, WI 53186 ·
[email protected] · Phone: 262.522.6503
If the noise is a varying siren, it is greatly reduced as well but not as much as a pure tone.
Transient sounds are greatly reduced, especially if they are repetitious.
The net effect of the Digital Signal Processor is to reduce static, hiss, ignition noise, power line noise,
carriers, hum, and heterodynes, while passing voice and CW signals.
The adaptive nature of the noise reduction is apparent by observing its convergent time. You will
hear a single tone vanish in about 1 second. White noise diminishes in 1 to 2 seconds. Typical car
noise and emergency alarms take about 2 seconds to reduce.
Power Amplifier
CLRspkr contains a power amplifier integrated circuit. It produces 4 watts maximum into the 8 ohm
internal loudspeaker, when supplied with a 13.8 volt dc source. It will produce around 6 watts if
connected to a 4 ohm loudspeaker. Note that the circuit has protection for a shorted speaker, and
protection for overheating.
ClearSpeech Adaptive Speech Filter
The ClearSpeech Adaptive Speech Filter is a patented algorithm designed to filter noise from audio
signals containing both speech and noise. It is implemented in a circuit board containing DSP
circuitry and a small audio power amplifier. The circuit board is purchased under license from the
manufacturer, NCT Group, Inc.
Immunity from RF Interference
CLRspkr contains circuitry to reduce interference from transmitted radio signal. There are filters on
all input wires, and decoupling capacitors at key points throughout the electronics. There is a ferrite
inductor in series with the positive power lead.
Audio input is via a coupling transformer. The audio input ground is not connected to the power
return. This helps reduce any ground loops.
Specifications
Dimensions:
5.5 x 4.3 x 2.5 inches
Power Requirements:
9 to 18 Vdc
Audio Input:
High impedance, 0.5 volts ac.
Frequency Response:
300 Hz to 3400 Hz
Noise Reduction Characteristics:
Adaptive, white noise greater than 15 dB
Single tone, greater than 50 dB.
ClearSpeech® is a registered trademark of NCT Group, Inc.
Powerpole® is a registered trademark of
Anderson Power Products
