Wireless MODEM for 950 MHz Digital Communication. Supervised by Dr. R C Tripathi. Abhishek Mitra and Nerdev Sharma IIIT Allahabad Fifth Semester Mini Project. 19 th February 2002. Backdrop:Guglielmo Marconi, pioneer of Wireless. Wireless. Communication but without wires.
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Dr. R C Tripathi
Abhishek Mitra and
Fifth Semester Mini Project
19th February 2002
Backdrop:Guglielmo Marconi, pioneer of Wireless
DDS Control Word From Parallel Port
Direct Digital Synthesizer
Crystal Oscillator @ 25 MHz
Data from Serial Port
9V to 3.3 V
RF Out 950MHz
f1 = Frequency transmitted for Binary 1 (950 MHz)
f2 = Frequency transmitted for Binary 0 (950.1 MHz)
f1 – f2 = Frequency Deviation (100 KHz)
The two peaks at 915.0 MHz and 915.10 Mhz demonstrate FSK.
10.7 MHz BPF
At the mixer output we get sum and difference of the two frequencies as the mixer multiplies the signals.
2 COS(A)*COS(B) = COS(A+B) + COS (A-B)
Data to Serial Port
Input from IF Stage
Quadrature FSK Demodulator
Output of Amplifier fed to Slicer
After Decision by Slicer
Figures showing the Wmodem