Wavetek 3SR Dokumentacja Pobierz pdf (Strona 117)

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both forward and reverse signals present. This phenomenon may

present itself when performing a reverse noise test using the Stealth

Model 3ST transmitter. To minimize the likelihood of this occur-

ring, the transmitter should be configured such that the video signal

input level is at approximately 0 dBmV. In the event that instru-

ment-related intermodulation occurs, the reverse channel plan may

be set up such that the frequencies at which the intermod products

appear are not included. Unfortunately this eliminates the ability to

monitor the headend for CPD from a field test point. Alternatively,

a Stealth Model 3HRV can be used. This instrument is used for

reverse testing only, and as no forward signals are present on its

input, it is not susceptible to this phenomenon.

Figure 6. Low pass filter recommended for use in CPD analysis

Ron Hranac, Coaxial International, ([email protected])

David Devereaux-Weber, University of Wisconsin - Madison,

Low Pass Fi l t er

Bi-Directi onal

Test Poi nt

Measurement

Instrument

Input

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Wavetek 3SR Dokumentacja Strona 117