If you didn't have modulation it'd be the same signal going out the whole time, like a continuous tone - which can't really tell you that much. By modulating the signal you can say much more.
Explain why modulation is necessary or desirable.
Operating system
to maintain the constant frequency and the phase parameters at the output
In Frequency Modulation (FM), if the modulation frequency is doubled, the modulation index does not necessarily double; it depends on the amplitude of the modulating signal. In Amplitude Modulation (AM), the modulation index is defined as the ratio of the peak amplitude of the modulating signal to the carrier amplitude, so it remains unchanged with varying modulation frequency. For Phase Modulation (PM), similar to FM, the modulation index is influenced by the amplitude of the modulating signal and does not inherently double with the modulation frequency. Thus, modulation frequency and modulation index are not directly linked in this way for FM, PM, or AM.
the modulation system is of FM
Explain why modulation is necessary or desirable.
modulation is necessary for transmitting low frequency signal to long range with desired qualitative information
Modulation in radio broadcasting is important because it is necessary to adjust the carrier signal so that the information in the modulating signal can be broadcasted. You must have modulation in order to transmit thru a radio wave.
The delta modulation transmits only one bit for one sample. Thus the signaling rate and transmission channel bandwidth is quite small for delta modulation. The transmitter and receiver implementation is very much simple for delta modulation. There is no analog to digital converter involved in delta modulation. The disadvantages of delta modulation are slope overload distortion and granular noise. These are the two drawbacks of delta modulation.
Operating system
The wave in amplitude modulation must be a sine wave. A sine wave represents smooth repetitive oscillation, which is necessary for this process.
modulation means transmitting the signal which is to be transmitted along with the carrier wave, then at the receiver it is separated from the carrier and demodulated. So modulation is needed so as to transmit the signal over long distances with higher accuracy. Hence it is required before multiplexing.
to maintain the constant frequency and the phase parameters at the output
AM - Amplitude Modulation FM - Frequency Modulation
modulation
Frequency Modulation and Phase Modulation
frequency modulation..