FM transmitter
Today,
I'm just gonna show you the FM transmitter that I made during my
EECE252 lab. This course is about signal and processing. We were given
two choice wheather to build FM transmitter or AM receiver. I chose to
build FM transmitter because FM is way cooler. huhu
I'm just gonna show you the FM transmitter that I made during my
EECE252 lab. This course is about signal and processing. We were given
two choice wheather to build FM transmitter or AM receiver. I chose to
build FM transmitter because FM is way cooler. huhu
Basically
the circuit is consist of input (microphone), mixer (BJT) and antenna
(wire). There is also a tuner (blue device) to tune the transmitter to
desired frequency.
the circuit is consist of input (microphone), mixer (BJT) and antenna
(wire). There is also a tuner (blue device) to tune the transmitter to
desired frequency.
FYI
FM signal consume huge bandwidth but as a trade off the signal is
almost imune to inteference while AM signal is vice versa.
FM signal consume huge bandwidth but as a trade off the signal is
almost imune to inteference while AM signal is vice versa.
This
is how it works: there is two different signals, one called information
signal and another is called carrier signal. The info signal which
contains our desired info i.e. voice, music, data etc. is then
modulated to the carrier signal which is basically a simple sinusoidal
wave range 88MHz to 108MHz (for standard FM radio spectrum) that carry
our info wirelessly accross the medium (air) to any radio (FM
receiver).
is how it works: there is two different signals, one called information
signal and another is called carrier signal. The info signal which
contains our desired info i.e. voice, music, data etc. is then
modulated to the carrier signal which is basically a simple sinusoidal
wave range 88MHz to 108MHz (for standard FM radio spectrum) that carry
our info wirelessly accross the medium (air) to any radio (FM
receiver).
We
also learn the mathematics behind it. For FM, after modulation the
frequency respond has Bassel Function property and it is depends on the
modulation index which is entirely depends on the designed circuit. For
AM simply find the product of two wave function.Here calculus play a
big role.
also learn the mathematics behind it. For FM, after modulation the
frequency respond has Bassel Function property and it is depends on the
modulation index which is entirely depends on the designed circuit. For
AM simply find the product of two wave function.Here calculus play a
big role.
So I did it within 45 minutes but only desparation I get. I tested it using a conventional radio but no sound coming out from it. I went home and try to troubleshoot it using multimeter but failed. Sigh!.... I saw others manage to tap the microphone and heard results on the radio which is so awesome. This is my first time building a real life FM transmitter (although I suck). Now I'm seeing my future as an electrical engineer become brighter and brighter. :)
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