What did Harry Nyquist do?
In 1932 Nyquist discovered how to determine when negative feedback amplifiers are stable. His criterion, generally called the Nyquist stability theorem, is of great practical importance. During World War II it helped control artillery employing electromechanical feedback systems.
Who discovered Nyquist theorem?
Harry Nyquist
| Harry Nyquist | |
|---|---|
| Nationality | Swedish |
| Citizenship | Swedish / American |
| Alma mater | Yale University University of North Dakota |
| Known for | Nyquist–Shannon sampling theorem Nyquist rate Johnson–Nyquist noise Nyquist stability criterion Nyquist ISI criterion Nyquist plot Nyquist frequency Nyquist filter Fluctuation dissipation theorem |
How do you calculate Nyquist frequency?
Divide the sampling rate by two to calculate the Nyquist frequency for your system. For example, if the sampling rate of your system is 10 Ms/s (10,000,000 samples per second), the Nyquist frequency of your system will be 5 MHz.
Why does Nyquist theorem matter?
This theorem was the key to digitizing the analog signal. Nyquist’s work states that an analog signal waveform can be converted into digital by sampling the analog signal at equal time intervals. Even today as we digitize analog signals, Nyquist’s theorem is used to get the job done.
Why do we use Shannon and Nyquist theorem?
The Nyquist–Shannon sampling theorem is a theorem in the field of signal processing which serves as a fundamental bridge between continuous-time signals and discrete-time signals. The theorem also leads to a formula for perfectly reconstructing the original continuous-time function from the samples.
What is aliased frequency?
Aliasing is an undesired effect in which the sampling frequency is too low to accurately reproduce the original analog content, resulting in signal distortion. Frequency aliasing is a common problem in signal conversion systems whose sampling rate is too slow to read input signals of a much higher frequency.
Who was Harry Nyquist and what did he do?
Harry Nyquist ( / ˈnaɪkwɪst /, Swedish: [ˈnŷːkvɪst]; February 7, 1889 – April 4, 1976) was a Swedish electronic engineer who made important contributions to communication theory. Nyquist was born in the village Nilsby of the parish Stora Kil, Värmland, Sweden.
How did Harry Nyquist contribute to feedback control theory?
The Nyquist stability criterion can now be found in all textbooks on feedback control theory. His early theoretical work on determining the bandwidth requirements for transmitting information laid the foundations for later advances by Claude Shannon, which led to the development of information theory.
Why was Harry Nyquist’s discovery called Johnson noise?
The understanding of noise is of critical importance for communications systems. Thermal noise is sometimes called Johnson noise or Nyquist noise because of their pioneering work in this field. In 1932 Nyquist discovered how to determine when negative feedback amplifiers are stable.
What is the significance of the Nyquist rate?
Nyquist rate: sampling rate twice the bandwidth of the signal’s waveform being sampled; sampling faster than this rate assures that the waveform can be reconstructed accurately. Nyquist frequency: half the sample rate of a system; signal frequencies below this value are unambiguously represented.