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  2. Coherence time (communications systems) - Wikipedia

    en.wikipedia.org/wiki/Coherence_time...

    Coherence time is actually a statistical measure of the time duration over which the channel impulse response is essentially invariant, and quantifies the similarity of the channel response at different times. In other words, coherence time is the time duration over which two received signals have a strong potential for amplitude correlation.

  3. Error correction code - Wikipedia

    en.wikipedia.org/wiki/Error_correction_code

    The code-rate of a given ECC system is defined as the ratio between the number of information bits and the total number of bits (i.e., information plus redundancy bits) in a given communication package.

  4. MACD - Wikipedia

    en.wikipedia.org/wiki/MACD

    The MACD indicator thus depends on three time parameters, namely the time constants of the three EMAs. The notation "MACD(a,b,c)" usually denotes the indicator where the MACD series is the difference of EMAs with characteristic times a and b, and the average series is an EMA of the MACD series with characteristic time c. These parameters are ...

  5. Coherence time - Wikipedia

    en.wikipedia.org/wiki/Coherence_time

    The coherence time, usually designated τ, is calculated by dividing the coherence length by the phase velocity of light in a medium; approximately given by = where λ is the central wavelength of the source, Δν and Δλ is the spectral width of the source in units of frequency and wavelength respectively, and c is the speed of light in vacuum.

  6. Analog-to-digital converter - Wikipedia

    en.wikipedia.org/wiki/Analog-to-digital_converter

    An analog signal is continuous in time and it is necessary to convert this to a flow of digital values. It is therefore required to define the rate at which new digital values are sampled from the analog signal. The rate of new values is called the sampling rate or sampling frequency of the converter.

  7. Digital signal - Wikipedia

    en.wikipedia.org/wiki/Digital_signal

    A digital signal is a signal that represents data as a sequence of discrete values; at any given time it can only take on, at most, one of a finite number of values. [1] [2] [3] This contrasts with an analog signal, which represents continuous values; at any given time it represents a real number within a continuous range of values. Simple ...

  8. List of mathematical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_mathematical_constants

    A mathematical constant is a key number whose value is fixed by an ... the constant π may be defined as the ratio of the length ... Wallis's constant 2.09455 ...

  9. Hedonic index - Wikipedia

    en.wikipedia.org/wiki/Hedonic_index

    A hedonic index is any price index which uses information from hedonic regression, which describes how product price could be explained by the product's characteristics.. Hedonic price indexes have proved to be very useful when applied to calculate price indices for information and communication products (e.g. personal computers) and housing, [1] because they can successfully mitigate problems ...