Mocomtech SLM-5650 - Manual (Page 37)

SLM-5650 Satellite Modem Revision 2
Introduction MN/SLM5650.IOM
1–17
1.8.5 BER Performance with Asymmetrical Adjacent Carriers
Operating in the presence of two adjacent asymmetrical carriers, one lower in frequency and one
higher in frequency, and each adjacent carrier symbol rate (R"
s
) = 2.0 R'
s
, the modem
performance is not degraded more than indicated in Table 1-10, Column four, and a and b.
Performance is measured with the adjacent carriers center frequencies offset (X/2) times
(R'
s
+ R"
s
) Hz from the test carrier center frequency, where X is the spacing factor and R'
s
is the
modulation symbol rate in Hz of the test carrier, and R"
s
is the modulation symbol rate in Hz of
each adjacent carrier. For modulation symbol rates below 38.4 ksps, this paragraph does not
apply.
a. For X (spacing factor) = 1.2, and R"
s
= 2.0 R'
s
, the asymmetric degradation shall
be IAW one of the values in Table 1-10, Column four, and the corresponding test
carrier E
s
/N
0
in Column one. Select a test carrier E
s
/N
0
that will yield timely
results based on modulation and coding used in the test configuration. The
adjacent carriers E
s
/N
0
are set to the corresponding value in Column two.
b. For the case of (1.4/2)(R'
s
+ R"
s
) Hz carrier spacing, the degradation is
< 0.2 dB.