Grass Valley Dictionary

Dictionary of Technical Terms - N

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NAM (non-additive mix)

1. A transition between two video signals in which the signal with the highest instantaneous amplitude is passed. 2. Addition of two or more video signals in a circuit in which the signal with the largest instantaneous amplitude is passed.

One one-billionth (0.000000001).

1 x 10-9 meter. Used in telecommunications as a measurement of signal wavelength.

nanosecond (ns)

One billionth of a second (0.000000001 second).

1. A communications channel of less than full voice grade. 2. A frequency band whose width is greater than 1 percent of the center frequency and less than one-third octave.

narrow blanking width

An adjustment of the width of blanking used in the early stages of video production that allows for a wider than normal image area. The blanking width is later widened to normal, which in effect, crops the image area horizontally and produces a visually cleaner edge.

Network channel terminating equipment.

Non-drop frame mode.

In telecommunications, the local end of a communications link.

negative NAM (non-additive mix)

Addition of two or more signals in a circuit in which the signal with the lowest instantaneous amplitude is passed.

1. The affiliation of television or radio stations such as ABC, CBS, NBC, CBC, BBC, etc. 2. A combination of electrical elements, such as a group of interconnected computers.

The range of grey levels, from black to white, but without color. For neutral areas in the image, the RGB signals will all be equal; in color difference formats the color difference signals will be zero.

Near instantaneous companded audio multiplex. A digital audio coding system originally developed by the BBC for point-to-point links. A later development, NICAM 728 is used in several European countries to provide stereo digital audio to home television receivers.

Unwanted disturbance within an electronic system. Interference pre-sent in a video picture.

The most common value for a conductor or component that falls between maximum and minimum limits of a tolerance range.

non-additive mix

noncomposite video

A video signal that includes blanking but no sync.

In GVG equipment specifications, refers to atmospheric humidity that has remained in vapor form and has not turned to liquid where it contacts equipment surfaces. (GVG specifications usually permit humidity up to 90%, non-condensing.)

non-drop frame time code

SMPTE time code format that continuously counts a full 30 frames per second. Because NTSC video does not operate at exactly 30 frames per second, non-drop frame time code will count 108 more frames in one hour than actually occur in the NTSC video in one hour. The result is incorrect synchronization of time code with clock time. Drop frame time code solves this problem by skipping or dropping two frame numbers per minute except at the tens of the minute count.

non-linear encoding

Relatively more levels of quantization are assigned to small amplitude signals, relatively fewer to the large signal peaks.

Having a gain varying as a function of signal amplitude.

non-sequential assembly

See checkerboard assembly.

non-sync detector

A circuit that detects when two video signals are not synchronous.

A memory system whose stored data is undisturbed by removal of operating power.

normalling jacks (through-connection)

Jacks that, when not acting as inputs or outputs, return the signal to its normal path by way of an internal spring connection inside the jack. (TV and portable radio earphone jacks are usually normalling.)

An arrangement of electronic components designed to attenuate a specific frequency band. Also called a "band stop filter."

Notice of proposed rulemaking.

Non-return to zero. A data stream in which the logic level remains a 1 during transmission of consecutive data 1's.

Non return to zero inverse. A video data scrambling scheme that is polarity insensitive. 0 = no change in logic; 1 = a transition from one logic level to the other.

National Telecommunications and Information Agency.

National Television Systems Committee. Organization that formulated standards for the NTSC television system. Now describes the American system of color telecasting which is used mainly in North America, Japan, and parts of South America. NTSC television uses a 3.579545 MHz subcarrier whose phase varies with the instantaneous hue of the televised color and whose amplitude varies with the instantaneous saturation of the color. NTSC employs 525 lines per frame and 59.94 fields per second.

numerical aperture

A number that defines the light gathering ability of a specific fiber. The numerical aperture is equal to the sine of the maximum acceptance angle.

Nyquist frequency (Nyquist rate)

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.

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