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  2. Q band - Wikipedia

    en.wikipedia.org/wiki/Q_band

    The Q band is a range of frequencies contained in the microwave region of the electromagnetic spectrum. Common usage places this range between 33 and 50 GHz, but may vary depending on the source using the term. [1] [2] The foregoing range corresponds to the recommended frequency band of operation of WR22 waveguides.

  3. q.h.s., qhs every night at bedtime quaque hora somni q.d.s, qds, QDS 4 times a day quater die sumendum q.i.d, qid 4 times a day quater in die q.h., qh every hour, hourly quaque hora q.o.d., qod every other day / alternate days quaque altera die q.p.m., qPM, qpm every afternoon or evening: quaque post meridiem q.s., qs a sufficient quantity

  4. Frequency-hopping spread spectrum - Wikipedia

    en.wikipedia.org/wiki/Frequency-hopping_spread...

    Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver .

  5. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and ...

  6. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves , are widely used in modern technology, particularly in telecommunication .

  7. Spectral efficiency - Wikipedia

    en.wikipedia.org/wiki/Spectral_efficiency

    Spread spectrum makes it possible to have as low a frequency reuse factor as 1, if each base station is divided into 3 cells by means of 3 directional sector antennas. This corresponds to a system spectrum efficiency of over 1 × 100 × 0.0017 = 0.17 (bit/s)/Hz per site, and 0.17/3 = 0.06 (bit/s)/Hz per cell or sector.

  8. Radar signal characteristics - Wikipedia

    en.wikipedia.org/wiki/Radar_signal_characteristics

    Radar transmission frequency spectrum of a trapezoid pulse profile Recent advances in signal processing techniques have made the use of pulse profiling or shaping more common. By shaping the pulse envelope before it is applied to the transmitting device, say to a cosine law or a trapezoid, the bandwidth can be limited at source, with less ...

  9. Optical heterodyne detection - Wikipedia

    en.wikipedia.org/wiki/Optical_heterodyne_detection

    The light signal is compared with standard or reference light from a "local oscillator" (LO) that would have a fixed offset in frequency and phase from the signal if the latter carried null information. "Heterodyne" signifies more than one frequency, in contrast to the single frequency employed in homodyne detection. [1]