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What happens if sampling is below the Nyquist rate?
As the sampling frequency decreases, the signal separation also decreases. When the sampling frequency drops below the Nyquist rate, the frequencies will crossover and cause aliasing.
What is the minimum Nyquist sampling rate?
The minimum sampling rate is often called the Nyquist rate. For example, the minimum sampling rate for a telephone speech signal (assumed low-pass filtered at 4 kHz) should be 8 KHz (or 8000 samples per second), while the minimum sampling rate for an audio CD signal with frequencies up to 22 KHz should be 44KHz.
What is the need of Nyquist rate in sampling process?
This theorem states that the highest frequency which can be represented accurately is one half of the sampling rate. The Nyquist rate specifies the minimum sampling rate that fully describes a given signal; in other words a sampling rate that enables the signal’s accurate reconstruction from the samples.
When the sampling frequency is less than the Nyquist value?
It is the critical rate of sampling. If the signal xt is sampled above the Nyquist rate, the original signal can be recovered, and if it is sampled below the Nyquist rate, the signal cannot be recovered. The following figure explains a signal, if sampled at a higher rate than 2w in the frequency domain.
Which is the correct sampling rate for the Nyquist frequency?
The Nyquist frequency is ( fs /2), or one-half of the sampling rate. In other words, the proper sampling rate (in order to get a satisfactory result) is the Nyquist rate, which is 2 x fM, or double the highest frequency of the real-world signal that you want to sample.
What is the problem with the Nyquist criterion?
The problem is that in this digital age, analogue signals are sampled digitally, i.e. at fixed sampling rates. The Nyquist criterion states that the sampling rate should be at least twice the target frequency of the signal. Suppose the target signal is a simple sinusoid with a frequency f (Fig. 1).
When does sampling rate need to be at least FS?
If a signal has frequency rate of fM, then the sampling rate needs to be at least fs such that: A term that is commonly used is the “Nyquist frequency.” The Nyquist frequency is ( fs /2), or one-half of the sampling rate.
What happens when you sample a sine wave below Nyquist?
Nyquist gives you the minimum sampling rate so that you can determine the frequency of a periodic wave. If you sample a sine wave at 0.75 Nyquist, you get a false sine wave as shown in black dashes. This is called aliasing and it occurs at any frequency below Nyquist.