How is amplitude modulation achieved?
Amplitude modulation is the process of varying the amplitude of the carrier signal in accordance with the amplitude of the message signal. Amplitude modulated signals can be produced by adding the carrier signal with the message signal and passing the resultant signal through a square law device (eg: FET).
What is efficiency of amplitude modulation?
We conclude that AM has a maximum practical efficiency of about 33 % due to the limitations placed on modulation index. If you try to improve the efficiency by raising m, you will introduce distortion when the signal is demodulated in the receiver.
What are the limitations of amplitude modulation?
Disadvantages of Amplitude Modulation:
- An amplitude modulation signal is not efficient in terms of its power usage.
- It is not efficient in terms of its use of bandwidth.
- AM detectors are sensitive to noise hence an amplitude modulation signal is prone to high levels of noise.
- Reproduction is not high fidelity.
What is meant by amplitude?
Amplitude, in physics, the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of the vibration path.
What is bandwidth in FM?
FM radio uses frequency modulation, of course. The frequency band for FM radio is about 88 to 108 MHz. The information signal is music and voice which falls in the audio spectrum. If FM transmitters use a maximum modulation index of about 5.0, so the resulting bandwidth is 180 kHz (roughly 0.2 MHz).
What are the advantages of FM over AM?
The main advantages of FM over AM are:
- Improved signal to noise ratio (about 25dB) w.r.t. to man made interference.
- Smaller geographical interference between neighboring stations.
- Less radiated power.
- Well defined service areas for given transmitter power.