Tektronix 1760 series, Руководство пользователя

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Glossary
G-4
1760 Series Component Waveform/Vector Monitor User Manual
CW
Continuous Wave. Refers to a separate subcarrier sine
wave used for synchronization of chrominance information.
dB (Decibel)
A decibel is a logarithmic unit used to de-
scribe signal ratios. For voltages, dB = 20 Log
10
(V
1
/V
2
).
DC-Coupled
A connection configured so that both the
signal (AC component) and the constant voltage on which it
is riding (DC component) are passed through.
DC Restorer
A circuit used in picture monitors and wa-
veform monitors to clamp one point of the waveform to a
fixed DC level.
Demodulator
In general, this term refers to any device
which recovers the original signal after it has modulated a
high-frequency carrier. In television it may refer to:
(1) An instrument, such as a TEKTRONIX 1450, which
takes video in its transmitted form (modulated onto the pic-
ture carrier) and converts it to baseband.
(2) The circuits which recover R--Y and B--Y for NTSC sys-
tems or U and V for PAL systems from the composite signal.
Digital Components
Component signals in which the
values for each pixel are represented by a set of numbers.
Distortion
If a sine wave of a single frequency is put into
a system, and harmonic content at multiples of that frequen-
cy appears at the output, there is harmonic distortion present
in the system. Harmonic distortion is caused by nonlineari-
ties 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. Adja-
cent lines in the picture are in alternate fields.