The Illustrated Dictionary of Electronics - Loscha

occultation • odometry 489netic radiation from that object. 2. The eclipsingof one object by another.occupied band A frequency band used by at leastone transmitting station regularly.occupied bandwidth For a given emission, thecontinuous band of frequencies (f 2 f 1 ) for whichthe mean (average) radiated power above f 2 andbelow f 1 is 0.5 percent of the total mean radiatedpower.occupied orbit In an atom, an orbit in which anelectron is present.Ocean Phonetic alphabet code word for the letter O.OCR Abbreviation of OPTICAL CHARACTER REC-OGNITION.oct Abbreviation of OCTAL.octal Abbreviation, oct. Based on the number eight.See, for example, OCTAL NUMBER SYSTEM.octal digit One of the figures in the group 0through 7 used in the OCTAL NUMBER SYSTEM.octal notation See OCTAL NUMBER SYSTEM.octal number system The base-eight system ofnumber notation. It uses digits 0 through 7.Compare BINARY NUMBER SYSTEM and DECI-MAL NUMBER SYSTEM. The octal system is oftenused as shorthand for otherwise-cumbersome binarynumbers. The binary number is separatedinto groups of three digits from right to left; eachsuch group is then converted into its decimalequivalent, with the result being the octal form ofthe binary number [e.g., binary 111 001 011 = octal713 (111 = decimal 7; 001 = decimal 1; and011 = decimal 3)].Decimal Octal0 01 12 23 34 45 56 67 78 109 1110 1211 1312 1413 1514 1615 1716 20octal number systemoctal-to-decimal conversion Conversion of numbersin the octal number system to numbers inthe more-familiar decimal number system.This is done by expressing the octal number seriallyin powers of eight. Thus, octal 12 = (1 × 8 1 ) +(2 × 8 0 ) = 8 + 2 = decimal 10.octant One-eighth of a circle; therefore, 45 degrees,or 0.5 quadrant.octave 1. The range of frequencies between a givenfrequency ( f ) and twice that frequency (2f ).2. The range of frequencies between a given frequency( f ) and half that frequency ( f/2).octave band A band of frequencies one octave wide(see OCTAVE).octave-band noise analyzer A noise analyzer havingbandpass-filter channels whose center frequenciesare one octave apart.octave-band pressure level Sound pressure levelwithin an OCTAVE BAND.octave pressure level See OCTAVE-BAND PRES-SURE LEVEL.OCTL Abbreviation of OPEN-CIRCUITED TRANS-MISSION LINE.octonary signal An eight-level signaling code.octonary system See OCTAL NUMBER SYSTEM.OD Abbreviation of OUTSIDE DIAMETER.odd-even check A method of checking the integrityof data transferred in a computer system, in whicheach word carries an extra digit to show whetherthe sum of ones in the word is odd or even.odd harmonic In a complex waveform, a harmonicthat is an odd-numbered multiple of the fundamentalfrequency (e.g., third harmonic, fifth harmonic,etc.). Compare EVEN HARMONIC.odd-harmonic intensification In a complex waveform,emphasis of the amplitude of odd harmonics,with respect to that of even harmonics, aproperty of some multivibrators and nonsinusoidalwaves.odd line In a conventional television picture, oneof the 262.5 odd-numbered horizontal linesscanned by the electron beam in developing theodd-line field. Compare EVEN LINE.odd-line field On a conventional television screen,the complete field obtained when the electronbeam has traced all the odd-numbered lines.Compare EVEN-LINE FIELD.odd-line interlace See ODD-LINE FIELD.odd parity check A computer check for an oddnumber of ones or zeros in digital data.Odex Trade name for a series of autonomousrobots developed by Odetics, Inc. They use legsfor locomotion. Noted for their ability to maneuverin places that most robots cannot reach.odograph An electromechanical or electronic plotterthat traces the path of a vehicle on a map, oron the image of a map as portrayed on a displayscreen.odometer An electromechanical device that indicatesthe speed of, and distance covered by, amoving vehicle or robot. Some such devices give aconstant position indication, via mathematicalintegration of the measured velocity (speed anddirection), relative to time. It can function in one,two, or three dimensions.odometry A method of speed, velocity, and/or positionsensing. It is commonly used in mobile