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  2. Sound amplification by stimulated emission of radiation

    en.wikipedia.org/wiki/Sound_amplification_by...

    This concept can be more conceivable by imagining it in analogy to laser theory. Theodore Maiman operated the first functioning LASER on May 16, 1960 at Hughes Research Laboratories, Malibu, California, [6] A device that operates according to the central idea of the "sound amplification by stimulated emission of radiation" theory is the thermoacoustic laser.

  3. Sampling (signal processing) - Wikipedia

    en.wikipedia.org/wiki/Sampling_(signal_processing)

    The image sampling frequency is the repetition rate of the sensor integration period. Since the integration period may be significantly shorter than the time between repetitions, the sampling frequency can be different from the inverse of the sample time: 50 Hz – PAL video; 60 / 1.001 Hz ~= 59.94 Hz – NTSC video

  4. Perot Museum of Nature and Science - Wikipedia

    en.wikipedia.org/wiki/Perot_Museum_of_Nature_and...

    On September 20, 1946, the Dallas Health Museum was founded by a group chartered as the Dallas Academy of Medicine. It was renamed the Dallas Health and Science Museum in 1958. The name was changed yet again to the Science Place in 1981. In 1995, the Dallas Children's Museum was founded elsewhere. An exterior view of the museum's main staircase

  5. Intermodulation - Wikipedia

    en.wikipedia.org/wiki/Intermodulation

    A frequency spectrum plot showing intermodulation between two injected signals at 270 and 275 MHz (the large spikes). Visible intermodulation products are seen as small spurs at 280 MHz and 265 MHz. 3rd order intermodulation products (D3 and D4) are the result of nonlinear behavior of an amplifier.

  6. Harmonic analysis - Wikipedia

    en.wikipedia.org/wiki/Harmonic_analysis

    Harmonic analysis is a branch of mathematics concerned with investigating the connections between a function and its representation in frequency.The frequency representation is found by using the Fourier transform for functions on unbounded domains such as the full real line or by Fourier series for functions on bounded domains, especially periodic functions on finite intervals.

  7. Discrete-time Fourier transform - Wikipedia

    en.wikipedia.org/wiki/Discrete-time_Fourier...

    From uniformly spaced samples it produces a function of frequency that is a periodic summation of the continuous Fourier transform of the original continuous function. In simpler terms, when you take the DTFT of regularly-spaced samples of a continuous signal, you get repeating (and possibly overlapping) copies of the signal's frequency ...

  8. Four-wave mixing - Wikipedia

    en.wikipedia.org/wiki/Four-wave_mixing

    This diagram describes the four-wave mixing interaction between frequencies f 1, f 2, f 3 and f 4. When three frequencies (f 1, f 2, and f 3) interact in a nonlinear medium, they give rise to a fourth frequency (f 4) which is formed by the scattering of the incident photons, producing the fourth photon.

  9. Amplifier - Wikipedia

    en.wikipedia.org/wiki/Amplifier

    The frequency range handled by an amplifier might be specified in terms of bandwidth (normally implying a response that is 3 dB down when the frequency reaches the specified bandwidth), or by specifying a frequency response that is within a certain number of decibels between a lower and an upper frequency (e.g. "20 Hz to 20 kHz plus or minus 1 ...