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An absorption wavemeter is a simple electronic instrument used to measure the frequency of radio waves.It is an older method of measuring frequency, widely used from the birth of radio in the early 20th century until the 1970s, when the development of inexpensive frequency counters, which have far greater accuracy, made it largely obsolete.
More advanced systems were of the deflection type, ordinarily used for measuring low frequencies but capable of being used for frequencies as high as 900 Hz. There are two common types, the BTH resonance frequency meter and the Weston frequency meter. Both use electrical resonance to create a magnetic field to move a pointer, differing in their ...
Used to measure the time between alternating power cycles. Also a casual term for a short period of time. centisecond: 10 −2 s: One hundredth of a second. decisecond: 10 −1 s: One tenth of a second. second: 1 s: SI base unit for time. decasecond: 10 s: Ten seconds (one sixth of a minute) minute: 60 s: hectosecond: 100 s: milliday: 1/1000 d ...
the maximum modulation frequency (or range of modulation frequencies) of an optical modulator; the range of frequencies in which some measurement apparatus (e.g., a power meter) can operate; the data rate (e.g., in Gbit/s) achieved in an optical communication system; see bandwidth (computing).
Spectrum analyzer based measurement can show the phase-noise power over many decades of frequency; e.g., 1 Hz to 10 MHz. The slope with offset frequency in various offset frequency regions can provide clues as to the source of the noise; e.g., low frequency flicker noise decreasing at 30 dB per decade (= 9 dB per octave). [3]
The modified Allan variance measure is a frequency stability measure, just as is the Allan variance. ... The degrees of freedom represents the number of free ...
A pendulum with a period of 2.8 s and a frequency of 0.36 Hz. For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term frequency is defined as the number of cycles or repetitions per unit of time.
A frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency counters usually measure the number of cycles of oscillation or pulses per second in a periodic electronic signal. Such an instrument is sometimes called a cymometer, particularly one of Chinese manufacture. [citation needed]