CD audio, for example, has a sampling rate of 44.1 distortion that is caused by audio signals with frequencies higher than the Nyquist frequency, which is half of the system's sampling rate.
32.
When a signal is sampled at a frequency that is at least double the Nyquist frequency, it can be fully reconstructed by low-pass filtering since the first repeat spectra does not overlap the original baseband spectra.
33.
A few may also publish MTF curves, while others ( especially intensifier manufacturers ) will publish the response ( % ) at the Nyquist frequency, or, alternatively, publish the frequency at which the response is 50 %.
34.
Let's sample it faster than the Nyquist frequency, and compute respective Fourier transform FT ( f ) = F _ 1 ( w ) and discrete-time fourier transform DTFT ( f ) = F _ 2 ( w ).
35.
:: : That would have been true back in the bad old days of analogue transmission, but today, everything but " the last mile " is T1 / E1 carrier or its equivalent, and that has a Nyquist frequency of 4KHz.
36.
In digital instruments, the sampling rate of the analog to digital converter ( ADC ) is a factor, but the stated analog bandwidth ( and therefore the overall bandwidth of the instrument ) is usually less than the ADC's Nyquist frequency.
37.
As per the Nyquist & ndash; Shannon sampling theorem, a DAC can reconstruct the original signal from the sampled data provided that its bandwidth meets certain requirements ( e . g ., a baseband signal with bandwidth less than the Nyquist frequency ).
38.
This allows the anti-aliasing filter to be designed with a 3 dB down point of 2 MHz and an effective cutoff at 10 MHz ( the Nyquist frequency ), avoiding the artifacts of a very steep ( " brick-wall " ) filter.
39.
The maximum frequency that can be unambiguously represented by " digital " data is \ textstyle f _ s / 2 ( known as Nyquist frequency ) when the samples are real numbers, and \ textstyle f _ s when the samples are complex numbers.
40.
According to a generalized sampling theorem, N independent representations of a signal, each subsampled at 1 / N of the signal's Nyquist frequency, allow for the unambiguous " reconstruction " of the original signal from the aliased Doppler spectra of the N representations.
