# The 'Nyquist theorem' specifies the minimum sampling rate to be

 [ A ]    equal to highest frequency of signal [ B ]    twice the highest frequency of a signal [ C ]    None of these [ D ]    twice the bandwidth of a signal [ E ]    equal to lowest frequency of signal
 Answer : Option D Explanation : The Nyquist Theorem, also known as the sampling theorem, is a principle that engineers follow in the digitization of analog signals. Any analog signal consists of components at various frequencies. The highest frequency component is an analog signal determines the bandwidth of that signal. The higher the frequency, the greater the bandwidth, if all other factors are held constant. Suppose the highest frequency component, in hertz, for a given analog signal is fmax. So, according to Nyquist theorem, the sampling rate must be at least 2 fmax, or twice the highest analog frequency component. If the sampling rate is less than 2 fmax, some of the highest frequency components in the analog input signal will not be correctly represented in the digitized output.