Appendix B UNITS OF MEASUREMENT

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Name	Abbreviation	Unit of	Equivalent or definition
atmosphere	atm	pressure	1 atm is normal atmospheric pressure 1 atm = 1.013 x 105 N/m2 = 1.013 bar = 14.7 lbs/in2
bar	-	pressure	1 bar = 106 dynes/cm2 = 106 µbar = 0.9869 atm
bel	-	intensity level	see decibel below
cent	-	frequency ratio (interval)	1 cent corresponds to a frequency ratio of 21/1200 100 cents = 1 semitone 1200 cents = 1 octave
cycles per second	cps	frequency	1 cps = 1 Hz (see hertz below)
decibel	dB	intensity level	1 dB = 0.1 bel = log I1/I2 where I1 = 10.I2
dyne	dyn	force	1 dyn = 10-5 N = 1 gm cm/sec2
erg	-	energy	1 erg = 10-7 J = 1 gm cm2/sec2
gigahertz	gHz	frequency	1 gHz = 109 Hz = 103 mHz = 106 kHz
hertz	Hz	frequency	1 Hz = 1 cycle/sec = 1 cps 1000 Hz = 1 kHz = 1 kc
joule	J	energy	1 J = 107 erg = 1 kg m2/sec2
kilocycle	kc	* frequency	1000 cycles 1 kilocycle/sec = 1 kc = 1000 cps = 1 kHz
kilohertz	kHz	frequency	1 kHz = 1000 Hz
megacycle	mc	* frequency	106 cycles 1 megacycle/sec = 1 mc = 106 cps = 1 mHz
megahertz	mHz	frequency	1 mHz = 106 Hz = 103 kHz
mel	-	pitch	1000 Hz at 40 dB is defined as 1000 mels
microbar	µbar	pressure	1 microbar = 10-6 bar = 1 dyne/cm2 Threshold of Hearing is 2 x 10-4 µbar
microsecond	µsec	time	1 µsec = .001 ms = 10-6 sec
mil	-	distance (thickness)	1 mil = .001 inch
millisecond	ms	time	1 ms = .001 sec
Newton	N	force	1 N = 105 dyn = 1 kg m/sec2
noy	-	noise	See PERCEIVED NOISE LEVEL
Pascal	Pa	pressure	1 Pa = 1 N/m2 = 106 µPa
phon	-	loudness	See: PHON, EQUAL LOUDNESS CONTOURS
sabin	-	absorption	1 sabin is equivalent to 1 squre foot of a surface absorbing all incident energy
sone	-	loudness	1 sone = 40 phons
watt	w	energy flow or power	1 watt = 1 joule/sec

* The terms kilocycle and megacycle, just as the basic term cycle, are often used loosely meaning frequency units. Proper frequency specification would be cycles/sec, kilocycles/sec, megacycles/sec. Partly due to this ambiguity, ther terms hertz, kilohertz and megahertz have been introduced as standard units of frequency.

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