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Will anyone tell me some of the applications coincidence detectors have in measurements and instrumentation? I would like to know whether there are any sensors utilizing coincident detection for measurements of any kind (applications of the coincident detector for sensing any parameter).

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  • \$\begingroup\$ PET scanning for one en.wikipedia.org/wiki/Positron_emission_tomography see the 'Emission' section \$\endgroup\$
    – Neil_UK
    Oct 21, 2021 at 15:15
  • \$\begingroup\$ What did you have in mind? \$\endgroup\$ Oct 21, 2021 at 18:13
  • \$\begingroup\$ @TonyStewartEE75 I need an example of a sensor (used for measuring some parameter like voltage) that makes use of the coincident detector. Can it be used in signal conditioning? \$\endgroup\$ Oct 21, 2021 at 18:27

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There are thousands, perhaps billions of examples ( as Carl Sagan would say) of “coincidence detection” in both time, frequency and spacial domains.

This applies in both analog and digital domains.

Coincidence has several meanings but originally meant in the same space and time. For the purpose of this answer, I will choose only electronic examples. It could be in same time in picoseconds or nanoseconds and up with a timing window to include events and exclude all others.

1: by chance, or by accident, meaning random without known correlation. e.g. Noise in a signal or looking for a pattern of periodic signals in the time and frequency domain . e.g. the SETI project ;)

2: An occurrence in nature e.g. "Mother Nature" by season or diurnal changes or by imperfections such as dust or moisture in transformer oil or by design of engineered combustion response high voltage pulse ignition coil triggers combustion of fuel. (Spark plug)

  • Unintended coincidence example: Partial Discharge or PD are the events that occur due to high voltage in a contaminating molecule with a lower dielectric detonation of particles occurs when excited with excessive electric field [kV/mm] creating an initial tiny spark at the same phase in a sinusoidal high voltage. This may occur in AC transmission of high voltage and may be detected coincidentally by UV, gamma rays, Rigowski coils, camera, UHF antenna when contaminants get accelerated in or on the surface of a insulator or dielectric. This may cascade into bigger detonations and is measured by the nanocoulombs of discharge and the coincident time in phase of a grid cycle.

3: Coincidence of pulses such as ionizing particles or photo emissions by stimulated emission of an isotope, CATscan, PET scan, Gamma etc in two or more detectors simultaneously, or of two or more signals simultaneously in a circuit.

An unusual coincidence is the emission of a single photon from a diamond with stimulation within a 1ns window.

4: Coincidence of digital "sync pattern" , an expected digital serial pattern in a synchronous channel.

  • Auto-correlation bit patterns are often selected for frame sync to enable possible detection in the presence of bit errors where the coincidence pattern of matching bits peaks during when expected in a shift register. Before this occurs, one must have word sync after clock sync by coincidence of bit energy transition or state of "1 or 0" (read SERDES decoder), bit edge ,centre clock edge or any other method of extracting clock from data transitions or Run-length limited (RLL code) patterns, depending on the baseband encoding and detector type.

What a coincidence?

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  • \$\begingroup\$ Any questions? Need more examples? hall sensors coincident with magnetic flux reversal of rotor. If too early, the motor or fan stalls in BLDC control. \$\endgroup\$ Oct 21, 2021 at 23:38

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