Wavetek 3HRV Manual de usuario descargar pdf (Pagina 4)

4

Making accurate digital average power

measurementsis addressed with the

digiCheckmeasurement function. The

digiCheckfeature is compatible with

most non-bursty digitalmodulations in

use today (that is, 16, 32, 64, and 256

QAM, QPR, QPSK, VSB, and CAP16).

Analog and digital signal limits

Analog signalthreshold limits have

always been a technician’s favorite fea-

ture of Acterna instruments. Automatic

limit checks provide a quickGO/NO-GO

status for audio and video levels. The

SDA Series extends this capability with

a dedicated digitallimit set that can be

applied exclusivelyto the forward digi-

tal carriers defined in a channel plan.

By assigning separate analog and digi-

tal limits, test time is reduced, since no

calculation is necessary to determine if

analog and digitallevel relationships

are within system specifications.

Analog and digital limitcapabilities

are available in both the Scan and

Autotest modes.

Sweepless Sweep display

Graphical reverse testpointcompensation The Navigator userinterface, common on all

Acterna SDA meters

Tilt measurement

Tilt is the easiest and mostefficient

tool for balancing amplifiers. For cable

plants requiring multiple tilt measure-

ments, such as comparing today’stilt

measurementwith a historicalrecord,

and then making an additionalmeas-

urement for a new wider channel plan,

the technician simply uses markers to

indicate the tilt channels that define

the new limits.

Intermodulation distortion

Intermodulation distortion (CSO/CTB)

can be automatically measured using

the CTB/CSO mode from the spectrum

analyzer. CTB/CSO distortions pro-

duced by intermodulation of analog TV

carriers can degrade the signal quality

of QAM modulated signals used by

digitalvideo and cable modems.

Scan measurement

Scan mode provides a quickgraphical

view of the entire channel plan with

bars representing the video levelfor

each channel. Both video and audio

may be displayed.

Carrier-to-noise measurement:

in-service

Carrier-to-noise measurement (on

non-scrambled channels) is justas

easy, and there is no need to remove

modulation from the video carrier.

No tunable preselector filter is needed.

Hum measurement: in-service

Measuring hum on a channel (non-

scrambled) isas simple aspressing the

“HUM” keyand since the instrument is

battery powered, the measurement is

independent of ground loops, there-

fore isolated from the line (mains).

Hum reveals itself as either single

(60 Hz) or double (120 Hz) horizontal

bars across the video screen. The level

of either can be measured.

The single-channel level display shows both video

and audio levels (eithersingle or dual sound/

NICAM) and the difference between the two

Digital channel average power measurements can

be made using the digiCheck

™

feature

Tilt mode performs automatictilt calculations

between any two of nine designated carriers

1 2 3 4 5 6 7 8

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