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Atomic clocks usually have an external PPS output, although internally they may operate at 9,192,631,770 Hz. [3] PPS signals have an accuracy ranging from 12 picoseconds to a few microseconds per second, or 2.0 nanoseconds to a few milliseconds per day based on the resolution and accuracy of the device generating the signal.
A heart rate monitor (HRM) is a personal monitoring device that allows one to measure/display heart rate in real time or record the heart rate for later study. It is largely used to gather heart rate data while performing various types of physical exercise. Measuring electrical heart information is referred to as electrocardiography (ECG or EKG).
Resting heart rate is often correlated with mortality. In the Copenhagen City Heart Study a heart rate of 65 bpm rather than 80 bpm was associated with 4.6 years longer life expectancy in men and 3.6 years in women. [27] Other studies have shown all-cause mortality is increased by 1.22 (hazard ratio) when heart rate exceeds 90 beats per minute. [7]
A child aged 1–3 years old can have a heart rate of 80–130 bpm, a child aged 3–5 years old a heart rate of 80–120 bpm, an older child (age of 6–10) a heart rate of 70–110 bpm, and an adolescent (age 11–14) a heart rate of 60–105 bpm. [12] An adult (age 15+) can have a heart rate of 60–100 bpm. [12]
A pulse watch, also known as a pulsometer or pulsograph, [1] is an individual monitoring and measuring device with the ability to measure heart or pulse rate. Detection can occur in real time or can be saved and stored for later review.
Measuring the pulse rate is therefore a convenient way to estimate the heart rate. [7] Pulse deficit is a condition in which a person has a difference between their pulse rate and heart rate. It can be observed by simultaneous palpation at the radial artery and auscultation using a stethoscope at the PMI, near the heart apex , for example.
The PRF is normally much lower than the frequency. For instance, a typical World War II radar like the Type 7 GCI radar had a basic carrier frequency of 209 MHz (209 million cycles per second) and a PRF of 300 or 500 pulses per second. A related measure is the pulse width, the amount of time the transmitter is turned on during each pulse.
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).