Analog to analog conversion - Amplitude modulation

ANALOG TO ANALOG CONVERSION

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.

TYPES

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.

AMPLITUDE MODULATION

WHY WE NEED MULTIPLIER ?

• Has two analog inputs .• Output proportional to the product

of the two amplitudes• Ex. MICROPHONES

VIDEO

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.