Glossary

Distortion If a sine wave of a single frequency is put into a system, and harmonic content at multiples of that frequency appears at the output, there is harmonic distortion present in the system. Harmonic distortion is caused by non-linearities in the system.

Equalizer The pulses which occur before and after the broad pulses in the vertical interval.

Envelope Detection A demodulation process in which the shape of the RF envelope is sensed. This is the process used by a diode detector.

Field In interlaced scan systems, the information for one picture is divided up into two fields. Each field contains one half of the lines required to produce the entire picture. Adjacent lines in the picture are in alternate fields.

Frequency Modulation (FM) is the process by which the frequency of a carrier signal is varied in proportion to the signal of interest. In both the NTSC and PAL television systems, audio information is transmitted using FM.

Frame A frame (sometimes called a ”picture”) contains all the information required for a complete picture. For interlaced scan systems, there are two fields in a frame.

Front Porch The portion of the video signal between the end of active picture time and the leading edge of horizontal sync.

Gamma (NTSC) Since picture monitors have a non-linear relationship between the input voltage and brightness, the signal must be correspondingly predistorted. Gamma correction is always done at the source (camera) in television systems: the R, G, and B signals are converted to R1/V, G1/V, and B1/V. Values of about 2.2 are typically used for gamma.

Gamma (PAL) Since picture monitors have a non-linear relationship between the input voltage and brightness, the signal must be correspondingly predistorted. Gamma correction is always done at the source (camera) in television systems: the R, G, and B signals are converted to R1/V, G1/V, and B1/V. Values for gamma range from 2.2 to 2.8.

G-4

1740A/1750A Series Waveform/Vector Monitor User Manual