Chapter 1 Flashcards
Cards pertaining to the basics of DSP
In this spectrum graph, what do the two axis represent?
- The X-axis is the range of frequencies
- The Y-axis shows the strength or amplitude of each frequency component.
What is the fundamental frequency?
The fundamental frequency is the lowest frequency component of a signals spectrum.
What is the dominant frequency?
The dominant frequency is that of a signal which has the largest amplitude.
What are harmonics?
Harmonics are the higher frequency signals which intersect with the fundamnetal frequency at it’s offset point. (this is probably the wrong word)
What is phase, and how is it measured ?
A phase offset is a measurement of where in a period a certain signal component starts. It is measured in radians.
What is a timestep ?
Time step is the duration between samples. It is calculated by dividing 1 by the sample frequency.
What is a harmonic strucure?
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What is the Nyquist Frequency?
The highest frequency measurable by a given sampling rate, which is usually 1/2 the sample frequency.
What is the difference between fft and rfft (numpy)
fft is the numpy module which procides functions pertaining to the Fast Fourier Transform. rfft is an fft process that real values, not complex ones.
What is a spectrogram?
A spectrogram is a common way to visualize non-periodic signals. It is a two dimensional representation of a span of frequencies (y axis) in the time domain (x-axis) with some symbolic representation of amplitude of the signal (often color) to represent the strength of certain frequencies at a given time. Think Reaper frequency comparisons.
What is this symbol ?
That is the symbol “Phi” which represents phase.
Frequency is the _______ of phase, conversely, phase is the ________ of frequency.
Frequency is the derivative of phase, conversely, phase is the integral of frequency.
What is Leakage ?
Leakage is the manifestation of artificial signals in a spectrum analysis created through DFT related to the discontinuity at the beginning and end of the generated signal.
What is Windowing?
Windowing is a method for reducing leakage artifacts in signal data by smoothing out the discontinuity between the beginning and end of the segment.
Define Uncorrelated Uniform Noise
Uncorrelated uniform noise (UU Noise), is a signal which contains random values from a uniform distribution (every value in the range is equally likely). The aspect of this noise that makes it “uncorrelated” is that all the values are independant (no discernable connection or predictable sequence).
