Upload
subashini-pandiarajan
View
130
Download
3
Tags:
Embed Size (px)
Citation preview
MODULATION
process of varying one or more
properties of a periodic waveformcarrier
signal, with a modulating signal that contains information to be transmitted.
WHY TO MODULATE ANALOG SIGNAL?
Modulation is needed . . .• If the medium is Bandpass in nature.
• BANDPASS - the range of frequencies which are transmitted through a bandpass filter.
BANDPASS FILTER
• An electronic device or circuit.• Allows signals between two specific
frequencies to pass.• Prevents signals at unwanted
frequencies.• Example – Radio.
ANALOG ANALOG CONVERSION
• Analog signals are modified to represent analog data.
• Also known as Analog Modulation. • Required when BANDPASS is used.
AMPLITUDE MODULATION
• Process of changing the amplitude of high frequency carrier wave in accordance with intensity of signal is called AM.
• amplitude of the carrier wave : amplitude of the signal being modulated.
WHY WE NEED MULTIPLIER ?
• Has two analog inputs .• Output proportional to the product
of the two amplitudes• Ex. MICROPHONES
AMPLITUDE MODULATION
• If the modulation signal frequency increases, the amplitude of the carrier changes at a greater rate.
• B AM =2 B
• BAND WIDTH of AM Signal = TWICE the BANDWIDTH of MODULATING
Signal.
ADVANTAGES
• It is simple to implement.
• It can be demodulated using a circuit consisting of very few components.