[time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?
csteinmetz at yandex.com
Tue Jan 6 18:42:14 EST 2015
>At 50 MHz, the loss from the common port is 12.8 dB, and the isolation
>between two ports sets of ports is either 38 or 48 dB
To get the worst-case output-to-output isolation, you need to test
two output ports that are electrically adjacent (i.e., that share the
same last 2:1 splitter, assuming that the 1:16 is a hierarchy of 1:2
splitters -- which is the case with the multi-output splitters I'm
familiar with). You may already have found an electrically-adjacent
pair (ports 7 and 8), but to be absolutely sure, you would need to
repeat the test from one output to each of the 15 others (or find a
full internal connection diagram, which does not seem to be on the
If it is a hierarchy of 1:2 splitters, you are correct that it is
effectively two, 1:8 splitters. In that case, each output port on
one of the 1:8 splitters is electrically equidistant from all of the
output ports on the other 1:8 splitter. But the same is not true of
the output ports of just one of the 1:8 splitters. In that case,
there is one adjacent output port, two output ports at one remove,
and four output ports twice removed. The isolation is generally
worst between adjacent outputs, and better at each remove. It is
logical to think that the adjacent output ports are 1-2, 3-4, ...
7-8, ... and 15-16 -- but this may not be the case.
I wouldn't bother retesting with out-of-band signals, but when you
test at 10MHz it is something to think about.
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