Patent ID: 6611322
Filing Date: 2003-08-26
Classification: G01M

Abstract:
An optical time domain reflectometer (OTDR) comprising:light pulse generating means, connected to one end of an optical fiber to be measured, for selectively emitting light pulses having a plurality of wavelengths to the optical fiber to be measured; light receiving means for receiving a light reflected from the optical fiber to be measured and then outputting a signal corresponding to an intensity of the reflected light; storage means for storing a signal output from the light receiving means as waveform data for each of the wavelengths; arithmetic operation means for obtaining, by arithmetic operations, a position and properties of an event based on the waveform data for each of the waveforms stored in the storage means; a display unit having a first display region and a second display region; display controlling means for displaying the waveform data for each of the wavelengths stored in the storage means in the first display region of the display unit and also displaying in a list a position and properties of an event corresponding to each wavelength obtained by the arithmetic operations of the arithmetic operation means in the second display region of the display unit to thereby facilitate grasping of a difference in characteristics of an optical fiber caused by a difference in wavelengths on the list; and waveform comparing means for comparing waveform patterns of events that have different wavelengths and occurrence positions within a predetermined distance range of event occurrence positions for each wavelength detected to thereby decide whether the waveform patterns agree, wherein a plurality of events decided by the waveform comparing means that waveform patterns thereof agree are displayed in such a manner that it can be recognized that they are a common event occurring at the same position along the optical fiber line; wherein when displaying in a list a position and properties of an event corresponding to each wavelength obtained by arithmetic operations of the arithmetic operation means in the second display region of the display unit, the display controlling means displays in the form of a table at least a number, an occurrence position, a type, characteristic values including a splice (connection loss) and a return loss, an employed wavelength &lgr; of an event obtained by arithmetic operations for each waveform data, and the display controlling means displays the events in a list in such a manner that common event numbers are added to the events which occur at common positions along the optical fiber to be measured.