PICO MACOM, INC.
12500 Foothill Blvd. • Lakeview Terrace, CA 91342 • (818) 897-0028 • (800) 421-6511 • FAX (818) 834-7197
Signal Combining Methods
6
T
he output levels of the modulator should be
the same as the output of the off-air strip ampli-
fiers. The
PM45
modulators are usually com-
bined with either the
SP860
signal processor,
LBS/MBS/FMSEP/UBS
series strip amplifi-
ers. Three methods are suggested
to combine strip amplifier, modu-
lator and processor outputs.
T
he
PHC-12U
twelve channel passive headend
combiner
consists of two rows of directional
couplers combined by a hybrid splitter. The
directional coupler combining provides high
isolation (40 dB) between the inputs. Nor-
mally, the odd channels are combined on one
row while even channels are combined on the
other row of directional couplers. The com-
biner loss is 16 dB per channel.
T
he
CHC-16U/860
sixteen channel active
headend combiner provides both signal com-
bining and post amplification of the headend
signals. Up to 16 channels may be combined
using the
CHC-16U/860
. The combiner gain is
10 dB per channel.
T
he final method of combining signals uses
three hybrid splitters per headend rack. The
odd channels are combined in one splitter, the
even-channels in another splitter and the two splitters are combined to a
single output with a third splitter. Each rack is then combined with a final
splitter prior to the
CA-30RK860
post amplifier.
NOTE :
*
Denotes either LBS, MBS, HBS or FMS model numbers.
I N S TA L L AT I O N
SP860
*BS
V
A
+10dBm
+10dBmV
+55dBmV
RF
IN
RF
IN
Ch. 2
Ch. 3
Ch. 4
CHC-16U/860
+6 dB to +10 dB
Ch. 2
Ch. 3
Ch. 4
+29dBmV
+59dBmV
SP860
*BS
V
A
+45dBmV
+45dBmV
+45dBmV
+10dBmV
+10dBmV
RF
IN
RF
IN
PM45
PHC-12U
-16dB
CA-30RK860
SP860
*BS
V
A
+10dBmV
+10dBmV
EVEN CHANNELS
Ch. 2
Ch. 3
Ch. 4
ODD CHANNELS
+37dBmV
+37dBmV
+33dBmV
+60dBmv
RF
IN
RF
IN
CA-30RK860
10 dB
ATTENUATION
15 dB
ATTENUATION
+45dBmV
+45dBmV
+45dBmV
PM45
10 dB
ATTENUATION
15 dB
ATTENUATION
+45dBmV
+45dBmV
+45dBmV
PM45
10 dB
ATTENUATION
15 dB
ATTENUATION
3 dB
ATTENUATION
