CBSE Class 12-science Answered
What do you mean by bandwidth of a signal? How much bandwidth is considered adequate for (i) speech signal (ii) music signal (iii) video and TV signals?
The information or message signal are also called as base band signal. In general, it spreads over a range of frequencies called the signal bandwidth.
(i) For speech signals, frequency range is from 300 Hz to 3100 Hz at the maximum end. Hence the bandwidth of speech signals = 3100 Hz - 300 Hz = 2800 Hz.
(ii) Different musical instruments produce high frequencies covering the entire range of audible frequencies from 20 Hz to 20 kHz. Hence, a bandwidth of about 20 kHz is required for music signal.
(iii) Video signals require about 4.2 MHz of bandwidth. As TV signals contain both video as well as voice, hence a signal band width of 4.5 MHz is required. But to avoid interference among telecast by different TV stations, a TV channel is usually allotted 6 MHz of bandwidth for transmission.