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From early in the 20th century, the radio frequency of 500 kilohertz (500 kHz) was an international calling and distress frequency for Morse code maritime communication. . For much of its early history, this frequency was referred to by its equivalent wavelength, 600 meters, or, using the earlier frequency unit name, 500 kilocycles (per second) or 500 k
The hertz is defined as one per second for periodic events. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" [3] [4] and then adds: "It follows that the hyperfine splitting in the ground state of the ...
The first fully mechanical analog computer, the Z1, operated at 1 Hz (cycle per second) clock frequency and the first electromechanical general purpose computer, the Z3, operated at a frequency of about 5–10 Hz. The first electronic general purpose computer, the ENIAC, used a 100 kHz clock in its cycling unit. As each instruction took 20 ...
8 kHz: ISDN sampling rate 10 4: 10 kHz 14 kHz: Acoustic – the typical upper limit of adult human hearing 17.4 kHz: Acoustic – a frequency known as the Mosquito, which is generally only audible to those under the age of 24. 25.1 kHz Acoustic – G 10, the highest pitch sung by Georgia Brown, who has a vocal range of 8 octaves. 44.1 kHz
Up until the procedure was replaced by the Global Maritime Distress and Safety System (August 1, 2013 in the U.S.), maritime radio stations were required to observe radio silence on 500 kHz (radiotelegraph) for the three minutes between 15 and 18 minutes past the top of each hour, and for the three minutes between 45 and 48 minutes past the top ...
In this example there are 1000 pulses per second (one kilohertz pulse rate) with a gated pulse width of 42 μs. The pulse packet frequency in this example is 27.125 MHz of RF energy. The duty cycle for a pulsed radio frequency is the percent time the RF packet is on, 4.2% for this example ([0.042 ms × 1000 pulses divided by 1000 ms/s] × 100).
Today's NYT Connections puzzle for Tuesday, December 10, 2024The New York Times
The cycle per second is a once-common English name for the unit of frequency now known as the hertz (Hz). Cycles per second may be denoted by c.p.s., c/s, or, ambiguously, just "cycles" (Cyc., Cy., C, or c). The term comes from repetitive phenomena such as sound waves having a frequency measurable as a number of oscillations, or cycles, per ...