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ET 2530 FM Transmitter project
FM Transmitter Project 32ITTMAX2606
Antoine Gregory Belot
ET2530-Communication 1
ITT Technical Institute
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ET 2530 FM Transmitter project
FM Transmitter Operations
The FM Transmitter is a FM modulation Transmitter witch modulates an intelligence
signal and a carrier frequency. The modulation takes place in the MAX2606 chip. The tuning is
accomplished through the filter circuitry and the use of the 100,000 ohm pot. The volume is
controlled by the 10,000 ohm pot. The tuning circuitry is connected to pin 3 of the MAX2606
chip. The volume is also connected to pin 3. The output is taken from pin 6 and sent to an
antenna. Negative feedback is supplied to pin 4 from the output. Pin 5 is set for Vcc at 5V
through the use of a voltage regulator. The input signal is supplied through the use of 2 RCA
jacks.
From my experience the project was a success, I had no difficulties putting the circuit
together. I enjoyed soldering the components to the board; this gave me much needed practice. I
believe the sound was adequate for the power level of the transmitter. The only thing is when the
volume of the transmitter was too loud I got a little distortion.
Theory of operation
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ET 2530 FM Transmitter project
The FM transmitter works as follows first power is supplied through the voltage regulator
that steps down the voltage to 5 volts. Second pin 5 is supplied 5 volts from the voltage
regulator. Pin 6 is the output from the MAX2606 witch is supplied through a capacitor to remove
any DC element in the signal, and then the signal is sent to an antenna. Pin 6 through a voltage
divider the two 1,000 ohm resistors sends negative feedback to pin 4 for frequency stability. Five
volts is sent to the 100,000 ohm. Pot t set a differential between ground and Vcc in the pot.
Tuning is accomplished at pin 3 through the use of a 2 pole low pass filter the 100,000 ohm pot
accomplish that job by changing the RC circuit value. Volume is controlled by the 10,000 ohm
pot by limiting the current supplied by the RCA jacks. The inductance is used by the chip to
create a RLC circuit with in fact is part of the tuning circuit. The MAX2606 also amplifies the
signal for transmission through the antenna.
List of parts
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ET 2530 FM Transmitter project
7805 Voltage regulator IC
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ET 2530 FM Transmitter project
FM transmitter schematic
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