TeachLogic VoiceLink Plus - Manual (Page 7)

a brief word about infrared
Infrared is a light ray that is below the visible
spectrum, just like the sound spectrum extends
beyond your hearing ability. An example of infrared
transmission is the remote control for your TV set.
When a button is pressed, a beam of infrared light
is emitted by a Light Emitting Diode (LED) from the
remote control. It is detected by a receiving diode
in your TV set. When you press a certain command
on your control, the internal electronics cause the
infrared light to flicker in a programmed sequential
pattern (called modulating the light beam). The
modulated infrared beam is detected by a receiving
diode and is electronically decoded. The decoded
signal activates the circuitry to perform the
command function on your TV set.
So how does this apply to the infrared
communication system you are about to start
using? The microphone/transmitter has several
Light Emitting Diodes (LED) that emit infrared light
beams to the sensor located in the ceiling of the
room. Now when you talk into the microphone, the
microphone element modulates the light beam,
causing it to flicker in sync with your speech. The
sensor detects the sequential signal and the
electronic circuitry in the VoiceLink PLUS converts
that sequential signal into a line level analog audio
signal. Now that audio signal can be fed into an
amplifier. The amplifier magnifies the electronic
signal and sends it output to the speakers. This
causes the speaker cone to move in sync with
your voice. The speaker replicates your voice and
disperses your voice evenly throughout the room.
1
Infrared will not
penetrate a solid surface
thus preventing any
transmission going
out of the room.
“What’s said in
the room, stays in
the room”
IR transmission
The IR transmitter
transmits directly to the
sensor. However; due to
the strength of the IR
transmitter, the infrared
signal will bounce off the
walls, ceiling and floor for
reception thus providing
continuous connectivity
throughout the room.
Benefit: total freedom
of movement within the
room with no restriction
of orientation.