What is the Nyquist frequency formula?
The frequency fn = 1/2Δt is called the Nyquist frequency. When spectra are presented for digital data, the highest frequency shown is the Nyquist frequency.
Why is the Nyquist frequency half the sampling rate?
In units of samples per second its value is twice the highest frequency (bandwidth) in Hz of a function or signal to be sampled. Conversely, for a given sample rate, the corresponding Nyquist frequency in Hz is the largest bandwidth that can be sampled without aliasing, and its value is one-half the sample-rate.
What is Nyquist Theorem and why does it matter?
The Nyquist theorem specifies that a sinuisoidal function in time or distance can be regenerated with no loss of information as long as it is sampled at a frequency greater than or equal to twice per cycle.
How is the Nyquist frequency of a signal determined?
According to the Shannon-Whitaker theorem , accurate reconstruction of a signal requires sampling at a frequency which is at least twice the cut-off frequency. Given a system in which the signal is sampled at a frequency f0, the Nyquist frequency is defined as half the sampling frequency. f n =0.5f 0.
How is the Nyquist sampling theorem quantized?
Quantization is not discussed on this page. The Nyquist sampling theorem states that if a signal is sampled at a rate dscan and is strictly band-limited at a cutoff frequency fC no higher than dscan / 2, the original analog signal can be exactly reconstructed. The frequency fN = dscan / 2 is called the Nyquist frequency.
Is the Nyquist frequency too high for Moire?
As we have mentioned, system response above the Nyquist frequency (0.5 cycles per pixel), can lead to aliasing artifacts such as moiré, but there are some problems with MTF measurements— especially with the slanted-edge MTF measurement, which is Imatest’s preferred method (in most instances).
What kind of MTF response does Nyquist have?
With sharp lenses, MTF response extended well beyond the Nyquist frequency. The 14n behaved very badly in the vicinity of Nyquist (63 lp/mm), as shown in this MTF test chart image, supplied by Sergio Lovisolo.