Howtosignalprocessing
Key focus: As per Nyquist ISI criterion, to achieve zero intersymbol interference (ISI), samples must have only one non-zero value at each sampling instant. is the symbol period) shown in Figure 1, where the transmitter, channel and the receiver are represented as band-limited filters.
- What is the formula of Nyquist criterion?
- What does the Nyquist criterion tell us?
- What is Nyquist criterion pulses?
- How does pulse shaping reduce ISI?
What is the formula of Nyquist criterion?
According to Nyquist theory Z=N+P (for any system, whether it is stable or unstable). For the stable system, Z=0, i.e. No roots of characteristics equation should be at RHS. So for the stable system N = –P.
What does the Nyquist criterion tell us?
The Nyquist criterion states that a repetitive waveform can be correctly reconstructed provided that the sampling frequency is greater than double the highest frequency to be sampled.
What is Nyquist criterion pulses?
Nyquist proposed a condition for pulses p(t) to have zero-ISI when transmitted through a channel with sufficient bandwidth to allow the spectrum of all the transmitted signal to pass. Nyquist proposed that a zero–ISI pulse p(t) must satisfy the condition.
How does pulse shaping reduce ISI?
As the image illustrates, the maximum amplitude of the pulse-shaping filter occurs in the middle of the symbol period. In addition, the beginning and ending portions of the symbol period are attenuated. Thus, ISI is reduced by providing a pseudo-guard interval which attenuates signals from multi-path reflections.
