need for modulation

Need for Modulation - The velocity of electromagnetic waves is 3 x 10 8 ms - 1 . On the other hand, the velocity of sound waves cannot be used to transmit intelligence to far off places. Only electromagnetic waves can be made to do this. Modulation is extremely necessa..

The velocity of electromagnetic waves is 3 x 10 8 ms - 1 . On the other hand, the velocity of sound waves cannot be used to transmit intelligence to far off places. Only electromagnetic waves can be made to do thi..

(i) Various electrical machines and noises cause amplitude disturbance in the transmission of amplitude-modulated wave. This makes the reception noisy. So, there is a need for different type of modulation, which can reduce the noise factor. Frequency modulation..

The wireless signal consists of radio frequency (high frequency) carrier wave modulated by audio frequency (low frequency). The diaphragm of a telephone receiver or a loud speaker cannot vibrate with high frequency. Moreover, this frequency is beyond the audible range of human ear. So, i..

Symmetric Modem Configuration - The simplest approach to the design of modems is to treat the entire PSTN as a linear analog network. [Note that PSTN is almost entirely due to the use of pulse-code modulation (PCM) for the transmission of voice signals..

Hz (audio-frequency range) cannot be efficiently radiated and do not propagate well in space. (ii) Simultaneous transmission of different signals by different transmitters would lead to confusion at the receiver. In order to solve these problems; we need to devise methods to convert or tr..

. These results indicate that: Some changes occurs in the nuclei of cells during differentiation. Differentiation does not result in the loss of, or permanent inactivation of, the genes; in fact it turns off the genes in a reversible manner. This means that a differentiated cell can de-differentiat..

. The ground station converts the received signal with the help of digital international conversion equipment to the local standard before relaying it. Frequency modulation is used for both 'up channel' and 'down channel' transmission. Though FM needs a larger bandwidth, it offe..