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Early uses of the term Nyquist frequency, such as those cited above, are all consistent with the definition presented in this article.Some later publications, including some respectable textbooks, call twice the signal bandwidth the Nyquist frequency; [6] [7] this is a distinctly minority usage, and the frequency at twice the signal bandwidth is otherwise commonly referred to as the Nyquist rate.
Fig 1: Typical example of Nyquist frequency and rate. They are rarely equal, because that would require over-sampling by a factor of 2 (i.e. 4 times the bandwidth). In signal processing, the Nyquist rate, named after Harry Nyquist, is a value equal to twice the highest frequency of a given function or signal
The sampling theorem was implied by the work of Harry Nyquist in 1928, [11] in which he showed that up to independent pulse samples could be sent through a system of bandwidth ; but he did not explicitly consider the problem of sampling and reconstruction of continuous signals.
The Nyquist rate is defined as twice the bandwidth of the signal. Oversampling is capable of improving resolution and signal-to-noise ratio, and can be helpful in avoiding aliasing and phase distortion by relaxing anti-aliasing filter performance requirements. A signal is said to be oversampled by a factor of N if it is sampled at N times the ...
Both downsampling and decimation can be synonymous with compression, or they can describe an entire process of bandwidth reduction and sample-rate reduction. [ 1 ] [ 2 ] When the process is performed on a sequence of samples of a signal or a continuous function, it produces an approximation of the sequence that would have been obtained by ...
Nyquist's original paper also provided the generalized noise for components having partly reactive response, e.g., sources that contain capacitors or inductors. [6] Such a component can be described by a frequency-dependent complex electrical impedance (). The formula for the power spectral density of the series noise voltage is
Output signal bandwidth is 30 Mhz of video bandwidth for luma (Y) and 15 Mhz of video bandwidth for chroma (P b, P r). Audio is recorded with a sampling rate of 48 kHz stored at 16 bits per sample in linear tape tracks, sampling rate for luma is 74.25 Mhz and 37.125 Mhz for chroma stored at 8 bits per sample.
The noise power at the output of the amplifier (i.e. the noise power coupled to an impedance-matched load that is connected to the amplifier output) is P out = Gk B (T R + T amp)B, where G is the amplifier power gain, and T amp is the amplifier noise temperature. In the Y-factor technique, P out is measured for two different, known values of T R.