Sometimes we have to send low frequency information, like the tone of the voice of someone talking on a telephone, over a specific channel that only permits a specific high frequency, such as radio frequencies (RF). So how do we do that? One simple, cost effective, and bandwidth efficient method is to change, or modulate, a known RF signal a certain way. Some common ways of modulating such a high frequency signal are Amplitude Modulation and Frequency Modulation. Each of these modulation techniques has its own advantages and disadvantages and are therefore more useful in certain applications.
the modulation system is of FM
Need for modulation: 1. Length of the antenna for a transmitter is inversly proportional to the frequency of the signal to be transmitted. So we try shift the frequency of the singal for the transmission to higher frequencies. 2. Every transmission of signal in a bandwidth is assigned with a particular frequency which is attained by modulating the signal with the carrier frequency. Different modulation techniques are implemented according to the requirements and compatibilities
QAM is a combination of phase modulation & amplitude modulation.
Frequency modulation Phase modulation
whatbis GMSK MODULATION ?
modulation
if we need simple transmitter and receiver, if we need low bandwidth
due to space vector modulation we can eliminate the lower order harmonics
amplitude modulation using collector modulator gives:More symmetrical envelope• Higher power efficiency• Higher output power• Need higher amplitude modulatingsignal
In a radio system ... Modulation is applied to a carrier. If the carrier wasn't modulated it wouldn't carry any information other than that the transmitter was working. Not very useful. It is the modulation which contains the "information" which we want to send.
Without modulation, there's be no way to get any information onto a carrier signal. There are several different types of modulation schemes for radio carriers and almost as many different types demodulators to decode the information so that it can be converted into a usable form. For instance, AM (amplitude modulation), FM (frequency modulation), digital modulation, quadrature amplitude, etc.
AM - Amplitude Modulation FM - Frequency Modulation
Frequency Modulation and Phase Modulation
if you are talking about a plane then its to set new modes unpromising if you will
frequency modulation..
due to velocity modulation density modulation occurs in TWT
The difference between frequency modulation and phase modulation is that with frequency modulation the angular frequency of the signal is modified while with the phase modulation, the phase angle of the signal is modified.