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28-449: The AN/SQS-26 weighed 27,215 kg (59,999 lb). It could be operated as a passive sonar on the 1.5 kHz frequency or as an active sonar at 3–4 kHz. Its maximum output was 240 kW and it had a range from 18 to 64 km (11 to 40 mi). It had direct path, bottom reflected, passive and convergence zone (CZ) capabilities. The original AX sonars were manufactured by General Electric Heavy Military Electronics. The "R" suffix

56-548: A more detailed treatment of this and the above frequency ranges, see Electromagnetic spectrum . Gravitational waves are also described in Hertz. Current observations are conducted in the 30–7000 Hz range by laser interferometers like LIGO , and the nanohertz (1–1000 nHz) range by pulsar timing arrays . Future space-based detectors are planned to fill in the gap, with LISA operating from 0.1–10 mHz (with some sensitivity from 10 μHz to 100 mHz), and DECIGO in

84-703: A person, the first letter of its symbol is uppercase (Bq). However, when an SI unit is spelled out in English, it should always begin with a lowercase letter (becquerel)—except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case . Like any SI unit, Bq can be prefixed ; commonly used multiples are kBq (kilobecquerel, 10  Bq ), MBq (megabecquerel, 10  Bq , equivalent to 1 rutherford ), GBq (gigabecquerel, 10  Bq ), TBq (terabecquerel, 10  Bq ), and PBq (petabecquerel, 10  Bq ). Large prefixes are common for practical uses of

112-499: Is an SI derived unit whose formal expression in terms of SI base units is s , meaning that one hertz is one per second or the reciprocal of one second . It is used only in the case of periodic events. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves . For high frequencies, the unit is commonly expressed in multiples : kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of

140-506: Is now only used for periodic phenomena. While 1 Hz replaces the deprecated term cycle per second , 1 Bq refers to one event per second on average for aperiodic radioactive decays. The gray (Gy) and the becquerel (Bq) were introduced in 1975. Between 1953 and 1975, absorbed dose was often measured with the rad . Decay activity was given with the curie before 1946 and often with the rutherford between 1946 and 1975. As with every International System of Units (SI) unit named after

168-473: Is the photon's energy, ν is its frequency, and h is the Planck constant . 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" and then adds: "It follows that

196-656: Is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as an activity of one per second , on average, for aperiodic activity events referred to a radionuclide. For applications relating to human health this is a small quantity, and SI multiples of the unit are commonly used. The becquerel is named after Henri Becquerel , who shared a Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity. 1 Bq = 1 s A special name

224-452: Is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). with the latter known as microwaves . Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens of terahertz (THz, infrared ) to a few petahertz (PHz, ultraviolet ), with the visible spectrum being 400–790 THz. Electromagnetic radiation with frequencies in the low terahertz range (intermediate between those of

252-446: The 0.1–10 Hz range. In computers, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz ( MHz ) or gigahertz ( GHz ). This specification refers to the frequency of the CPU's master clock signal . This signal is nominally a square wave , which is an electrical voltage that switches between low and high logic levels at regular intervals. As

280-468: The 1970s. In some usage, the "per second" was omitted, so that "megacycles" (Mc) was used as an abbreviation of "megacycles per second" (that is, megahertz (MHz)). Sound is a traveling longitudinal wave , which is an oscillation of pressure . Humans perceive the frequency of a sound as its pitch . Each musical note corresponds to a particular frequency. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20 000  Hz ;

308-636: The SQS-26CX and SQS-53 sonars is the digital computer interface with the Mk 116 anti-submarine warfare (ASW) weapon control system in the latter. In addition, AN/SQS-53 sonar can be fitted with the Kingfisher small obstacle (mines) avoidance sonar. Specifications: Versions: Hertz The hertz (symbol: Hz ) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle ) per second . The hertz

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336-535: The activity of 1 gram of radium-226 . The curie is defined as 3.7 × 10  s , or 37 GBq. Conversion factors: The following table shows radiation quantities in SI and non-SI units. W R (formerly 'Q' factor) is a factor that scales the biological effect for different types of radiation, relative to x-rays (e.g. 1 for beta radiation, 20 for alpha radiation, and a complicated function of energy for neutrons). In general, conversion between rates of emission,

364-406: The amount of activity of these radioactive materials, but should not be confused with the amount of exposure to ionizing radiation that these materials represent. The level of exposure and thus the absorbed dose received are what should be considered when assessing the effects of ionizing radiation on humans. The becquerel succeeded the curie (Ci), an older, non-SI unit of radioactivity based on

392-476: The average adult human can hear sounds between 20 Hz and 16 000  Hz . The range of ultrasound , infrasound and other physical vibrations such as molecular and atomic vibrations extends from a few femtohertz into the terahertz range and beyond. Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz. Radio frequency radiation

420-440: The event being counted may be a complete cycle); 100 Hz means "one hundred periodic events occur per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz , or a human heart might be said to beat at 1.2 Hz . The occurrence rate of aperiodic or stochastic events is expressed in reciprocal second or inverse second (1/s or s ) in general or, in

448-449: The hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, many experts have criticized this approach, which they claim is an easily manipulable benchmark . Some processors use multiple clock cycles to perform a single operation, while others can perform multiple operations in a single cycle. For personal computers, CPU clock speeds have ranged from approximately 1 MHz in

476-413: The highest normally usable radio frequencies and long-wave infrared light) is often called terahertz radiation . Even higher frequencies exist, such as that of X-rays and gamma rays , which can be measured in exahertz (EHz). For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies : for

504-616: The hyperfine splitting in the ground state of the caesium 133 atom is exactly 9 192 631 770  hertz , ν hfs Cs = 9 192 631 770  Hz ." The dimension of the unit hertz is 1/time (T ). Expressed in base SI units, the unit is the reciprocal second (1/s). In English, "hertz" is also used as the plural form. As an SI unit, Hz can be prefixed ; commonly used multiples are kHz (kilohertz, 10  Hz ), MHz (megahertz, 10  Hz ), GHz (gigahertz, 10  Hz ) and THz (terahertz, 10  Hz ). One hertz (i.e. one per second) simply means "one periodic event occurs per second" (where

532-454: The late 1970s ( Atari , Commodore , Apple computers ) to up to 6 GHz in IBM Power microprocessors . Various computer buses , such as the front-side bus connecting the CPU and northbridge , also operate at various frequencies in the megahertz range. Higher frequencies than the International System of Units provides prefixes for are believed to occur naturally in the frequencies of

560-727: The quantum-mechanical vibrations of massive particles, although these are not directly observable and must be inferred through other phenomena. By convention, these are typically not expressed in hertz, but in terms of the equivalent energy, which is proportional to the frequency by the factor of the Planck constant . The CJK Compatibility block in Unicode contains characters for common SI units for frequency. These are intended for compatibility with East Asian character encodings, and not for use in new documents (which would be expected to use Latin letters, e.g. "MHz"). Becquerel The becquerel ( / ˌ b ɛ k ə ˈ r ɛ l / ; symbol: Bq )

588-544: The rules for capitalisation of a common noun ; i.e., hertz becomes capitalised at the beginning of a sentence and in titles but is otherwise in lower case. The hertz is named after the German physicist Heinrich Hertz (1857–1894), who made important scientific contributions to the study of electromagnetism . The name was established by the International Electrotechnical Commission (IEC) in 1935. It

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616-413: The specific case of radioactivity , in becquerels . Whereas 1 Hz (one per second) specifically refers to one cycle (or periodic event) per second, 1 Bq (also one per second) specifically refers to one radionuclide event per second on average. Even though frequency, angular velocity , angular frequency and radioactivity all have the dimension T , of these only frequency is expressed using

644-480: The unit hertz. Thus a disc rotating at 60 revolutions per minute (rpm) is said to have an angular velocity of 2 π  rad/s and a frequency of rotation of 1 Hz . The correspondence between a frequency f with the unit hertz and an angular velocity ω with the unit radians per second is The hertz is named after Heinrich Hertz . As with every SI unit named for a person, its symbol starts with an upper case letter (Hz), but when written in full, it follows

672-403: The unit's most common uses are in the description of periodic waveforms and musical tones , particularly those used in radio - and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon , via the Planck relation E  =  hν , where E

700-460: The unit. For practical applications, 1 Bq is a small unit. For example, there is roughly 0.017 g of potassium-40 in a typical human body, producing about 4,400 decays per second (Bq). The activity of radioactive americium in a home smoke detector is about 37 kBq (1 μCi). The global inventory of carbon-14 is estimated to be 8.5 × 10  Bq (8.5 EBq, 8.5 exabecquerel ). These examples are useful for comparing

728-482: Was adopted by the General Conference on Weights and Measures (CGPM) ( Conférence générale des poids et mesures ) in 1960, replacing the previous name for the unit, "cycles per second" (cps), along with its related multiples, primarily "kilocycles per second" (kc/s) and "megacycles per second" (Mc/s), and occasionally "kilomegacycles per second" (kMc/s). The term "cycles per second" was largely replaced by "hertz" by

756-490: Was introduced for the reciprocal second (s ) to represent radioactivity to avoid potentially dangerous mistakes with prefixes. For example, 1 μs would mean 10 disintegrations per second: ( 10  s ) = 10  s , whereas 1 μBq would mean 1 disintegration per 1 million seconds. Other names considered were hertz (Hz), a special name already in use for the reciprocal second (for periodic events of any kind), and fourier (Fr; after Joseph Fourier ). The hertz

784-474: Was the result of a "Retrofit" by GE that incorporated improved designs derived from the AN/SQS-26CX sonar, also manufactured by GE. BX sonars were manufactured by EDO Corporation. CX sonars were manufactured by General Electric Heavy Military Electronics. AN/SQS-26CX sonar performs a 360-deg, long-range sector search at low frequency. AN/SQS-53 is an improved version of AN/SQS-26CX. The main difference between

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