Digital Equipment ChannelWorks, Network Installer Manual

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Pre-Installation Checklist B-7
CABLE PLANT - SITE EVALUATION
Cable Plant -- Site Evaluation
This section is intended to record the parameters requiring verification at each site where ChannelWorks
equipment will be installed. The parameters are divided into two groups. It is preferred that recorded values
in the first group be based on actual measurements to facilitate ease of installation and eliminate any potential
surprises. The values recorded in the second group may be based on actual measurements or on data recorded
at a recent cable plant certification.
The required specifications for a ChannelWorks network are given in Table 2. Note that one of the required
measurements is outlet to outlet variation. This is a target variation between signals transmitted at the
network outlets as measured at the input to the translator. This is a network wide specification based on data
taken at individual sites. To determine this value, complete all the individual site measurements and, from
that data, record the following:
Maximum Return Path Loss dB
Minimum Return Path Loss dB
Calculate:
Return Outlet to Outlet Variation dB
Max Return Path Loss - Min Return Path Loss
Table 2. Unit/Cable Plant Specifications
Use additional sheets to describe the test setup/equipment used for the measurements and to record any interfering
signals* or other possible problems observed while testing.
* = It is highly desirable to obtain operating channel peak hold plot recorded over a 24 hour period at the headend.
Transmit Center Frequency 10 MHz to 174 MHz
Transmit Power +54 dBmV typical
Receive Center Frequency 54 to 550 MHz
Receive Level -5 to +15 dBmV
Outlet to Outlet RX Level (at headend) Variation 6 dB
Amplitude Flatness
±
1 dB
Carrier to Noise Ratio
≥
30 dB
Carrier to Hum Ratio
≥
40 dB
Carrier to Second Order Beat
≥
60 dB
Carrier to Third Order Beat
≥
51 dB