# hertz

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## hertz

(hûrts) [for Heinrich R. HertzHertz, Heinrich Rudolf
, 1857–94, German physicist. He confirmed J. C. Maxwell's electromagnetic theory and in the course of experiments (1886–89) produced and studied electromagnetic waves (known also as hertzian waves, or radio waves).
], abbr. Hz, unit of frequency, equal to 1 cycle per second. The term is combined with metric prefixes to denote multiple units such as the kilohertz (1,000 Hz), megahertz (1,000,000 Hz), and gigahertz (1,000,000,000 Hz).

## hertz

(herts) Symbol: Hz. The SI unit of frequency, defined as the frequency of a periodic phenomenon that has a period of one second. The frequency range of electromagnetic radiation is about 3000 Hz (very low frequency radio waves) to about 1022 Hz (high-frequency gamma rays).

## hertz

[hərts]
(physics)
Unit of frequency; a periodic oscillation has a frequency of n hertz if in 1 second it goes through n cycles. Also known as cycle per second (cps). Symbolized Hz.

## hertz

A unit of frequency, abbr. Hz; one cycle per second.

## hertz

The frequency of any cyclic repetition. One hertz (Hz) is one cycle per second. The number of cycles per second is expressed in hertz. Kilohertz (kHz) is a frequency of one thousand cycles per second. Megahertz (MHz) is a frequency of one million cycles per second. The term is named after Heinrich Hertz, a German physicist (1857–1894). Also called a cycle.

## hertz

the derived SI unit of frequency; the frequency of a periodic phenomenon that has a periodic time of 1 second; 1 cycle per second.

## Hertz

1. Gustav . 1887--1975, German atomic physicist. He provided evidence for the quantum theory by his research with Franck on the effects produced by bombarding atoms with electrons: they shared the Nobel prize for physics (1925)
2. Heinrich Rudolph . 1857--94, German physicist. He was the first to produce electromagnetic waves artificially

## Hertz

Abbreviated "Hz," one Hertz is equal to one cycle per second. In 1883, Heinrich Hertz detected electromagnetic waves, and his name was adopted to measure the number of electromagnetic waves, or cycles, in a signal. Hertz is widely used to refer to the clock rate of a CPU; for example, 2 GHz means two billion cycles per second. The term is also used for other repeating cycles such as frame rate; for example, a 60 Hz TV displays 60 frames per second. See MHz, GHz and space/time.
References in periodicals archive ?
Basis for sudden cardiac death prediction by T-wave alternans from an integrative physiology perspective.
Also, the T-wave slope and the isoelectric level are required to be applied these algorithms.
The most common ECG abnormality associated with stroke was T-wave changes (44%).
DIAGNOSIS: Sinus rhythm; an atrial premature complex; sagging ST-segments, low T-waves, and prominent U-waves suggesting hypokalemia.
T-wave inversion is a particularly difficult conundrum in athletes as it may represent the only sign of an inherited heart muscle disease, even in the absence of any other features and before structural changes in the heart can be detected (15).
Keywords: Wellen's syndrome, T-wave inversion, Coronary angiography (JPMA 62: 548; 2012).
Among patients who died of CCHF, early QRS transition zone, T-wave changes, LBBB or RBBB were more frequently encountered compared to those who survived CCHF (Table 1).
The T-wave alternans was detected in simulated ECG signals.
Over 1 year, patients with the abnormal T-wave patterns were about twice as likely as other patients to have a cardiac event that necessitated a defibrillator.
Among these 177 patients, 68% had a positive or indeterminate T-wave alternans exercise test, while 32% had a QRS duration greater than 120 milliseconds.
Tests to identify a subset of patients who may not actually need or profit from a device--that would have tremendous implications for the cost-benefit ratio of this form of treatment," noted the cardiologist, who cochaired a session on T-wave alternans testing.
Studies show that heart patients with this electrical change, called T-wave alternans, face a much greater risk of arrhythmia and SCD than do those without the underlying disorder.

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