Abbreviation for nanoamp. One billionth of an Amp or 10-9 Amps.


NA Mismatch Loss

The loss of power at a joint that occurs when the transmitting half has a numerical aperture greater than the NA of the receiving half. The loss occurs when coupling light from a source to fiber, from fiber to fiber, or from fiber to detector.

NA Mismatch Loss


Abbreviation for National Association of Broadcasters. A trade association that promotes and protects the interests of radio and television broadcasters before Congress, federal agencies and the Courts.


National Electric Code® (NEC):




Abbreviation for National Cable Television Association. The major trade association for the cable television industry.


Near Infrared



Near-end Crosstalk (NEXT, RN)




Abbreviation for National Electrical Manufacturers Association. Organization responsible for the standardization of electrical equipment, enabling consumers to select from a range of safe, effective, and compatible electrical products.





Network Topology


Network Topology



Abbreviation for National Fire Protection Association. Publisher of the National Electrical Code®, and 300 other codes and standards through a full, open-consensus process.



Abbreviation for nanometer. One billionth of a meter or 10-9 meters.








Noise Equivalent Power (NEP)



Noise Figure (NF)



Non Dispersion-shifted Fiber (NDSF)



Non Dispersion-shifted Fiber (NDSF)



Non Zero-dispersion-shifted Fiber (NZ-DSF)




The deviation from linearity in an electronic circuit, an electro-optic device or a fiber that generates undesired components in a signal. Examples of fiber nonlinearities include SBS, SRS, FWM, SPM, XPM, and Intermodulation.



Abbreviation for nonreturn to zero. A common means of encoding data that has two states termed “zero” and “one” and no neutral or rest position.



Abbreviation for nanosecond. One billionth of a second or 10-9 seconds.





Numerical Aperture (NA)

The light-gathering ability of a fiber; the maximum angle to the fiber axis at which light will be accepted and propagated through the fiber. NA = sin a, where a is the acceptance angle. NA also describes the angular spread of light from a central axis, as in exiting a fiber, emitting from a source, or entering a detector.

Numerical Aperture (NA)


Abbreviation for nanowatt. One billionth of a Watt or 10-9 Watts.


Nyquist Frequency

The lowest sampling frequency that can be used for analog-to-digital conversion of a signal without resulting in significant aliasing. Normally, this frequency is twice the rate of the highest frequency contained in the signal being sampled. Also called Nyquist rate.