Fsk Modulation and Demodulation

2413 Words Aug 16th, 2011 10 Pages
FSK MODULATION AND DEMODULATION PROGRAM USING MATLAB

LIST OF TABLES:
CHAPTER 1: INTRODUCTION. 1.1-INTRODUCTION TO WIRELESS MODEM. 1.2-INTRODUCTION TO FREQUENCY SHIFT KEYING 1.2.1-FSK MODULATOR 1.2.2-FSK DEMODULATION
CHAPTER 2: COMPONENT DESCRIPTION. 2.1-LIST OF COMPONENTS 2.2-DESCRIPTION OF FUNCTIONAL DIAGRAM 2.2.1 IC 555.
2.2.2 565 PLL.
CHAPTER 3: CIRCUIT DIAGRAM AND WORKING.
3.1-CIRCUIT DIAGRAM OF FSK MODULATOR USING IC555.
3.2-CIRCUIT DIAGRAM OF FSK DEMODULATOR USING PLL 555
CHAPTER 4: OPERATION OF FSK. 4.1-OPERATION OF FSK MODULATOR USING IC555. 4.2-OPERATION OF FSK DEMODUALTOR USING PLL 565.
CHAPTER 5: PROGRAMING USING MATLAB. 5.1-FSK MODULATION USING MATLAB. 5.2-FSK DEMODULATOR USING MATLAB.
CHAPTER 6: OUTPUT
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On the receiving end, the demodulator works by detecting one or both of the frequencies, often with a band-pass filter, regenerating the input signal. You can also use a signal processor to convert the carrier from time domain to frequency domain with a fourier transform, and then pick off the signal that way.) The FSK method of modulating/demodulation is typically limited to low frequency signal rates, such as 300 bits per second
1.2.2: FSK DEMODULATION:
FSK demodulation is the process of recovering the original signal by detecting the frequencies involved in the original modulation. Typically, this is done with a bandpass amplifier tuned to one of the two frequencies, followed by a amplitude demodulator. The output is the original signal. It is possible, though often unecessary, to use two bandpass ampliers, one for each frequency, but this is redundant. It is also possible to use a digital signal processing technique to perform a fourier transform on the input signal, but that can be complex and costly.
This is the method used in very early modems, up to around 1200 baud.
It is also possible, using FSK, to send multiple signals across one line. Simply pick suitable frequencies for each modulation state, and mix the outputs into one consolidated analog signal. On the other end, you have multiple bandpass filters running at the same time and, as long as the chosen frequencies are

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