modulation is process of changing


Posted on Feb 4, 2014

Modulation is the process of changing some characteristics (e. g. amplitude, frequency or phase) of a carrier wave in accordance with the intensity of the signal is known as modulation. The figure shows the electronics circuit of a simple am modulator. It is essentially a CE amplifier having a voltage gain of A. The carrier signal is the input tothe amplifier. The modulating


modulation is process of changing
Click here to download the full size of the above Circuit.

signal is applied in the emitter resistance circuit. The carrier ec is applied at the input of the amplifier and the modulating signal es is applied in the emitter resistance circuit. The amplifier circuit amplifies the carrier by a factor A, so that the output is Aes. Since the modulating signal is a part of the biasing circuit, it products low frequency variations in the emitter circuit. This in turn causes variations in A . The result is that amplitude of the carrier varies in accordance with the strength of the signal. Consequently, amplitude modulated output is obtained across RL. It may be noted that carrier should not influence the voltage gain A; only the modulating signal should do this. To achieve this objective, carries should have a small magnitude and signal should have a large magnitude.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Knightrider lights for model cars
    Garden timer circuit with CD4000
    Atv Jr Transmitter 440Mhz Circuit
    Sound pressure meter
    Basics of Thyristors
    Power Conversion Principles
    Burglar alarm circuit
    By the PGA204 205 op amp OPA602 programmable AC coupled amplifier
    Source suspended programmable instrumentation amplifier PGA203
    Variety of signal generator circuit



    Top