Pdf amplitude modulation

Sharlene Katz James Flynn. Antenna too large! Use modulation to transfer information to a higher frequency. Amplitude modulation is the simplest of the three to understand. The transmitter just uses the information signal, Vm t to vary the amplitude of the carrier, Vco to produce a modulated signal, VAM t.

Here are the three signals in mathematical form Amplitude Modulation - A continuous-wave goes on continuously without any intervals and it is the baseband message signal, which contains the This wave has to be modulated. According to the standard definition, "The amplitude of the carrier signal varies in accordance with the instantaneous The FM bandwidth of the VCO is an important piece of design information for applications that require knowledge of how fast a VCO will respond. Figure- 3 Bessel Functions for FM carrier and sideband amplitude.

Modulation: What and Why? Join Meta-Analysis Resources. Powered by. Badges Report an Issue Terms of Service. This line helps recreating the exact shape of the modulating signal. This imaginary line on the carrier wave is called as Envelope. It is the same as the message signal. A carrier wave, after being modulated, if the modulated level is calculated, then such an attempt is called as Modulation Index or Modulation Depth.

It states the level of modulation that a carrier wave undergoes. The maximum and minimum values of the envelope of the modulated wave are represented by A max and A min respectively. Hence, the equation for Modulation Index is obtained. This is often denoted in percentage called as Percentage Modulation. It is the extent of modulation denoted in percentage, and is denoted by m. For instance, if this value is less than 1, i.

It is called as Under-modulation. Such a wave is called as an under-modulated wave. If the value of the modulation index is greater than 1, i. It would look like the following figure. Such overmodulated wave causes interference, which cannot be eliminated. The bandwidth is the difference between lowest and highest frequencies of the signal.