Wavetek 147 Specifikace stáhnout pdf (Strana 391)

Glossary

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Edit Box On many LCD screens you are required to make changes, or have

the option of making changes to system parameters. In these instances the

Edit box appears as the last line of the LCD screen. It also carries

instructions, when appropriate. such as “Press ENTER….”

Equalization Reducing distortion of frequency and/or phase by

compensating for attenuation and/or time-delay at frequencies within the

transmission band.

Frequency Modulation (FM) A modulating signal varies the frequency of

the carrier wave.

HDTV High Definition TV: can be either analogue or digital.

Headend The control center of a cable television system. The headend

receives incoming signals from satellites, broadcast antennae, etc., then

amplifies, converts, processes and combines signals as required for

transmission along cable lines to hubs or nodes for distribution to cable

subscribers’ house drops.

HFC Hybrid Fiber Coax

HPF High Pass Filter

HSM Headend Stealth Modem. Transmits spectrum data stored in the

PathTrak System Headend Control Unit to the StealthTrak meter via the

forward RF telemetry path.

Hub A signal distribution point that receives signals directly from the

headend; a sub-station comprising a collection of nodes. A hub facilitates

trouble-shooting and changes within the overall system. Larger cable

systems have multiple hub sites.

Hum Low-Frequency Modulation of a carrier when it passes through an

active or passive component. Shows on TV screen as bar(s) scrolling slowly

up through the picture. Measured in Stealth as dBmV or as a percentage.

Ingress RF “leaking in” to a reverse path, interfering with transmission.

Interruption into the cable line by through breaks in the integrity of the cable

Inter-modulation Modulation of a TV carrier frequency by power line

frequencies and harmonics, or other low-frequency disturbances.

Inter-modulation Distortion Nonlinear distortion produced by the presence

of inter-modulation. Harmonics are not included in this category.

IPPV Impulse Pay-Per-View

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Wavetek 147 Specifikace Strana 391