What are different methods of FM generation?

FM signals can be generated using either direct or indirect frequency modulation: Direct FM modulation can be achieved by directly feeding the message into the input of a voltage-controlled oscillator. For indirect FM modulation, the message signal is integrated to generate a phase-modulated signal.

What is direct & indirect method of FM generation?

Answer: Direct FM For direct FM, the instantaneous frequency is directly varied with the information signal. The carrier frequency is varied using an oscillator where its resonant frequency is determined by variable components. Indirect FM As mentioned in the lecture notes, FM and PM are related to one another.

What are the direct methods for the generation of FM What are the drawbacks of direct method?

In direct method of FM generation, as the carrier generation is directly affected by the modulating signal, it is not easy to get high order stability in carrier frequency. The non linear characteristics of varactor diode produce a distorted FM signal due to harmonics in the modulating signal.

What is direct FM generation?

In direct FM generation, the instantaneous frequency of the carrier is changed directly in proportion with the message signal. For this, a device called voltage controlled oscillator (VCO) is used. This will vary the frequency of the oscillator to produce FM. The devices used are FET, transistor or varactor diode.

What is the basic principle of FM generation?

The basic principle behind FM is that the amplitude of an analog baseband signal can be represented by a slightly different frequency of the carrier. We represent this relationship in the graph below.

What is the main disadvantage of FM?

Disadvantages of FM: Much more Bandwidth (as much as 20 times as much). More complicated receiver and transmitter.

Which modulation is better AM or FM?

With FM, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied. FM signals have a great advantage over AM signals. Both signals are susceptible to slight changes in amplitude. With an AM broadcast, these changes result in static.

Why FM is used?

FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. Therefore, FM is used for most broadcasts of music or general audio (in the audio spectrum).