Les fréquences

Contents

Fréquence & période

Formules de calculs de fréquences et de périodes

Symbole | Nom | Valeurs | Formule |

f | Fréquence |

Hz (Hertz)
10³Hz = KHz (Kilo Hertz)
10⁶Hz = MHz (Méga Hertz)
10⁹Hz = GHz (Giga Hertz)

| f = 1 / T |

T | Période |

s (seconde)
10^-3s = ms (milli seconde)
10^-6s = µs (micro seconde)

| T = 1 / f |

Exemples de calculs de fréquences

T=20ms => 1/(20.10^-3) = 10³/20 = 10²/2 = 100/2 = 50 Hz

T=125µs => 1/(125.10^-6) = 10^-6/125 = 1000000/125 = 8 KHz

f=62,5Hz => 1/62,5 = (1000/10³).16 = 16 ms.

Tranches du spectre de fréquences

Spectre de fréquences
Fréquences	Domaine d'application de ces fréquences
3 -> 30 KHz	VLF (Very low frequency).
30 -> 300 KHz	LF (Low frequency).
150 -> 300 KHz	Partie de LF qui comprend les ondes longues (radio civile).
300 KHz-> 3 MHz	MF (Medium frequency)
500 -> 1500 KHz	Partie de MF qui comprend les ondes moyennes (radio civile).
3 -> 30 MHz	HF (High frequency). Ondes courtes.
27 MHz	CB (radio amateur).
30 -> 300 MHz	VHF (Very high frequency).
30 -> 88 MHz	Télévision (bande 1).
88 -> 108 MHz	Bande FM civile
108 -> 150 MHz	Bande réservée à l'aviation.
150 -> 170 MHz	Bande réservée aux pompiers, ambulances, police, taxi.
170 -> 230 MHz	Télévision (bande 2).
230 -> 400 MHz	Bande réservée à l'aviation.
300 MHz -> 3 GHz	UHF (Ultra high frequency).
390 -> 1550 MHz	Bande L
460 -> 860 MHz	Télévision (bande UHF).
900 MHz	GSM
1,2 GHz	GPS
1 -> 8 GHz	Satcom
1550 MHz-> 3,9 GHz	Bande S
3,9 -> 6,2 GHz	Bande C (par exemple : Bemilcom)
3 -> 30 GHz	SHF (Supra high frequency).
6,2-> 10,9 GHz	Bande X (dont Satcom)
19 -> 20 GHz	Bande KU (TV Sat).
30 -> 300 GHz	EHF (Extremly high frequency).
300 -> 3000 GHz	ESHF (Extremly supra high frequency).

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Document created the 20/07/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/frequences.html

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