Jeulin Fibroptonic Mode D'emploi page 50

Optics
Fibroptonic
Ref : 202 012
1 Purpose
To discover the principle of optical fibre telephony (transmission through wire).
2 Experiment no. 7
ENGLISH
FIBROPTONIC
2.1 Equipment:
•
Transmitter
•
Receiver
•
Fibre
•
6, 9 or 12 V DC power supply
2.2 Experiment
•
Unwind the optical fibre as much as possible: the transmission and reception units
are separated by 5 m. Place the microphone switch on MIC and the transmitter
switch on On. The 2 green and red LEDs must come on.
•
A student speaks in the transmitter microphone (figure 12)
•
The receiver is placed on the table amongst the students. The sound can be
perfectly heard if the sound level (which we adjust using the potentiometer located
on the receiver unit) is sufficiently high.
Transmitter
Figure 12: Optical fibre telephone
2.3 Conclusion:
The transmitted audible signal modulates the infrared signal, which propagates through
the fibre. At the receiver end, the signal is "decoded" and the audible signal
reconstructed.
2.4 Alternative:
The student whistles regularly, the signal received can be viewed by connecting an
oscilloscope to the yellow and black terminals of the receiver.
This experiment therefore illustrates: the transmission, propagation, reception and
modulation of an infrared signal.
OPTICAL FIBER TELEPHONY
Optical fiber
Receiver
50
SHEET
04
Potentiometer