IBM 8265, Руководство по подготовке площадки

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IBM 8265: Planning and Site Preparation Guide
Common Mode Attenuation
Common mode attenuation measurements are made with the twisted pair driven and
monitored common mode with respect to the shield using a 50 ohm network analyzer.
No additional impedance matching devices are required.
Common mode attenuation in dB/km, measured on 100 m reels, must be bounded by
the following function:
for all frequencies (f) in MHz between 50 MHz and 600 MHz. k
o
is 95 dB/km for Type
1A and 135 dB/km for Type 9A.
Near-End Crosstalk (NEXT)
Notes:
1. Crosstalk measurements from 9.6 kHz to 20 MHz were performed on 305 m
(or greater) reels.
2. Crosstalk measurements from 20 MHz to 300 MHz were performed on 100 m
reels using a North Hills 13410 balun or equivalent.
3.
(f) in MHz.
Frequency Type 1A Type 9A Type 6A Notes
9.6 kHz–5 MHz -58 dB -52 dB -52 dB 1
8 MHz -54.9 dB -48.9 dB -48.9 dB 1
10 MHz -53.5 dB -47.5 dB -47.5 dB 1
16 MHz -50.4 dB -44.4 dB -44.4 dB 1
20 MHz -49.0 dB -43.0 dB -43.0 dB 1
5–20 MHz see note 3 see note 3 see note 3 1, 3
25 MHz -47.5 dB -41.5 dB -41.5 dB 2
31.25 MHz -46.1 dB -40.1 dB -40.1 dB 2
62.5 MHz -41.5 dB -35.5 dB -35.5 dB 2
100 MHz -38.5 dB -32.5 dB -32.5 dB 2
20–300 MHz see note 3 see note 3 see note 3 2, 3
A f
( )
k
0
f
50
-------
≤
NEXT(f) NEXT 5
( ) ≤
15
f
5
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 
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