ANEM Operating Manual
ANEM Operating Manual
Page 8
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Audio
Source
ANEM
Audio
In
Audio
Out
Power
2.4 Connections.
The
ANEM
is connected in-line between the equipment
and the loudspeaker or headphones, as shown in the
following block diagram.
Connect the 3.5mm mono lead supplied to the extension
speaker socket of your equipment and the audio in socket
on the
ANEM
. Connect a loudspeaker or headphones to
the audio out socket on the
ANEM
.
Warning:
The 3.5mm
mono Audio Out socket provides variable audio output
for an external speaker (4 ohm - 8 ohm impedance) or
earphones. The audio level varies according to the
volume setting of the equipment that the ANEM is being
used with. When you plug mono earphones into the Audio
Out socket (stereo earphones can be used with the bhi
audio adapter ADP-S001), the SP-PH toggle switch
MUST BE
set to the “PH” position, to prevent the
possibility of injury to your ears.
Look in section 6.4 for audio adapters to suit most
equipment and applications.
Connect the fused DC power lead to a power supply
capable of providing 12 - 18VDC @ 300mA. The centre
pin of the power connector is positive (the lead with the
white stripe is positive). If you require a separate power
supply then refer to section 6.4 for details.
The unit is now ready for use.
Figure 5. Block diagram
2.
Module Over
view
.
Page 21
The
ANEM
requires a signal of 125mV rms or greater for
optimum performance. Signals lower than this may be used
but the noise cancellation performance will decrease, as
the signal levels drops. If the unit is used with low level
signals such as microphones, the signal will need
amplifying before applying it to the
ANEM
.
Due to the adaptive nature of the noise cancellation a
small delay may be heard when the audio signal
changes. For optimum performance provide the module
with a constant signal where possible.
When switching on the unit a small audio thump may be
heard in the loudspeaker or headphones.
Figure 15. Input circuit -
module powered down
22
W
OUT
12
Agnd
Agnd
9
10
V
Audio
Input
R6
IN
Load
11
The audio input to the
module is loaded at
22
W.
This load is
effectively connected
across the output load
when the unit is
switched off
(bypassed).
This will reduce the
impedance presented
to the audio source.
For example:
8
W
will reduce to 5.9
W
4
W
will reduce to 3.4
W
4.3.3 Change to output load.
4.3.4 Other signal considerations.
4.
Technical Information.
Speaker or headphones
