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2.
Introduction
The bhi
Desk Top “Noise Away” amplified DSP noise cancelling speaker greatly
improves
the clarity and intelligibility of speech in radio and voice communication systems. It is
suitable for use in base station applications where background noise and interference
mean that you cannot clearly hear what is being said. The speaker will enable the user to
listen and concentrate “
stress-free
”. Suitable applications where the speaker will be of
great benefit are: Amateur radio, two-way radios, HF radios, marine communications,
scanners, taxi base stations etc.
The Desk Top “Noise Away”
incorporates unique DSP
technology to remove unwanted
background noise and interference from speech and has
up to 8 DSP filter levels, allowing
the user to optimise for their level of noise and
interference.
The speaker simply connects into the exten
sion speaker socket or
headphone socket of the radio communications equipment.
The Desk Top “Noise Away” comprises a 4” bass driver and a 1” tweeter unit, and an
amplified DSP noise cancelling unit capable of producing up to 2.5Watts RMS audio
power. The unit requires an audio input signal of between 80 and 500mW level and a DC
supply of between 12 and 18 Volts (300mA). The unit is supplied with a 1.2 metre audio
cable with a moulded 3.5mm jack plug for the audio input, as well as a 2.1mm fused DC
power lead and user manual.
The
bhi
Desk Top “Noise Away” is easy to set up and its functions are microprocessor
controlled, enabling simple operation via two the pushbuttons on the front of the speaker
grille: Power on/off audio bypass and DSP filter on/off and level select. The last selected
settings remaining in the memory when the unit is switched off.
Note:
The
speaker
is designed for speech signals and is not really suitable for music.
3.
DSP Noise cancellation.
The bhi DSP processes the incoming signal and differentiates the speech from the noise.
The unwanted noise and interference is then attenuated to leave only the speech. The
following diagrams are taken from actual audio signals and illustrate how the signal is
being processed.
Original signal.
Speech with a lot of background noise
Processed speech.
Speech with reduced noise
bhi
Desk Top “Noise Away” amplified DSP noise cancelling speaker
