- Any periodic waveform can be expressed as the sum of sine waves with frequencies at integer or harmonic multiples of the fundamental frequency of the waveform and with appropriate maximum amplitudes and phases.. - Reed organ is also called Harmonica, as the reeds are tuned to vibrate at harmonics of the fundamental signal.. - Spectrum, of a signal is the range of frequencies that it contains. - Bandwidth, of a signal is the width of the spectrum. - The bandwidth of the intelligent voice signal is 3100 Hz. - Bit rate, is the number of bits transmitted per second.. - Baud rate, is the signaling speed. - That is the number of times the signal changes its value , e.g., voltage per second.. - 2400Hz) to represent 0 and 1 per unit time of the signal. - So, the maximum bit rate is the same as the signal rate, 3.1 kbps.. - Power is the amount of energy per unit time and is unit is Watts.. - The milliwatt is the unit of measure used for power in telecommunications circuits.. - The relative power of output to input will tell us the gain of the amplifier, P o /P I = 1000mW/10mW. - The unit of measure used to compare two power levels is the decibel (dB).. - dB tells us the ratio of two power levels, that is it expresses the gain of the system.. - Signal-to-Noise Ratio:. - One of the most fundamental laws used in telecommunications is Shanon's law.. - For a bandwidth of 3.1 kHz and a signal to noise ratio of 30 dB (a ratio of 1000/1), the maximum data rate is 31 kbps.
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