TeachLogic Spectrum III User Manual
Page 7
a brief word about infrared
Infrared is a light ray that is below the visible
spectrum, just like the sound 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 the 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 corner 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 Spectrum III 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 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
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.
Infrared will not
penetrate a solid surface
thus preventing any
transmission from
going out of the room.
“What’s said in
the room, stays in
the room”.