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Ramin Farmani - Ahmad Bahreyni
Summer 2009
Design and Develop a
88-108MH !"#$ %8&m'FM (ransmi))er
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*re+a,e
Designing a Transmitter
FM & AM a brief introduction
Class C Power Amplier a briefintroduction
Designing Circuit
Schematic and PCB Dipole and agi Antenna
Tuning
!"#$"#$%%#'% M() *+!,att FM Transmitter
-
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Designing a (ransmi))er
Analog & Digital Comple.it/
0.tra Comple.it/ in 1F 0lectronic
Dene our Pro2ect 1e3uests 4o5ernmental 1ules in Countries
!"#$"#$%%#'% M() *+!,att FM Transmitter
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FM AM Modula)ion
FM & AM in Broadcasting
AM a Brief 6ntroduction
FM a Brief 6ntroduction
!"#$"#$%%#'% M() *+!,att FM Transmitter
7
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./ASS . AM*/FR
!"#$"#$%%#'% M() *+!,att FM Transmitter
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8ce
6c
Class A
Class AB
Class B
.lass .
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./ASS B AM*/FR R$
The Class B amplier is biased at cuto9: in other words there is no bias+
The amplier relies on the input signal to bias the transistor+ The rst '+; 5olts of thesignal in is lost because the transistor does not turn on until the base 5oltage reaches'+;8+
Amplier is 5er/ e+
Amplier is used to amplif/ power in situations where wa5eform is not important ?power
supplies@
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+V
12V
1kTP1
1.0 kHz
-5/5V
1k
NPN
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./ASS . BAS34
The Class C amplier has a negati5e 5oltage at the base and )ero 5olts at the
emitter+ The Base0mitter 2unction is re5erse biased+ The transistor will turn on at a
signal 5oltage of 7+;8+ The transistor will onl/ conduct a small pulse through to the
collector output+
Amplier is 5er/ e
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CASS C APP6CAT6E
Collector resonant circuit responds to an impulse b/ =ringing> at its resonant
fre3uenc/+ This is liGe pushing someone on a swing+ A sharp short push each trip
allows the swing to oscillate bacG and forth at its resonant fre3uenc/+ Collector
impulses occur b/ design at the resonant fre3uenc/ of the tanG circuit+ 1esonant
circuit continues to ring and restores the sine wa5e at the output Class C Amplier is
used in radio"1F applications and is also called a =tuned> amplier+
!"#$"#$%%#'% M() *+!,att FM Transmitter
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1 u F
C11uH
-4V DC
+V
12V
TP3
1.0 kHz
-5/5V
1k
NPN
Positi5e alternations lled in b/tanG circuit ring
1esonant ?tanG@ circuit
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Designing .ir,ui)
Audio Preamplier
!"#$"#$%%#'% M() *+!,att FM Transmitter
H
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Designing .ir,ui)
FM Modulator and Escillator
!"#$"#$%%#'% M() *+!,att FM Transmitter
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!"#$"#$%%#'% M() *+!,att FM Transmitter
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