PICO MACOM INC.
12500 Foothill Blvd. • Lakeview Terrace, CA 91342 • (818) 897-0028 • (800) 421-6511 • FAX (818)824-7197
Signal Combining Methods - CATV Channels
T
he output levels of the modulator should be
the same as the output of the off-air strip ampli-
fiers. The
PFAM 550SUB
modulators are
usually combined with either the
SP600
**,
LBS/HBS
**
or
72
series strip amplifiers. Three
methods are suggested to combine
strip amplifier, modulator and
processor outputs.
I N S T A L L A T I O N
6
T
he
CHC-16U
** provides both signal com-
bining and post amplification of the headend
signals. Up to 16 channels may be combined
using the
CHC-16U
. The combiner gain is 15
dB per channel.
T
he
PHC-12U
consists of two rows of direc-
tional 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.
*BS - Denotes low, medium, high and superband 2 volt strip amps.
72* - Denotes low, medium. and high band 4 volt strip amps.
** - Also available for 220 VAC NTSC systems.
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-30RK550
** post amplifier.
Ch. 2
Ch. 3
Ch. 4
+36dBmv
+60dBmv
M600
SP600
*BS/72*
V
A
+52dBmv
+52dBmv
+52dBmv
+10dBmv
+14dBmv
+10dBmv
SP600
*BS/72*
V
A
+52dBmv
+52dBmv
+52dBmv
+10dBmv
+14dBmv
+10dBmv
M600
SP600
*BS/72*
V
A
+50dBmv
+50dBmv
+50dBmv
+10dBmv
+14dBmv
+10dBmv
Ch. 2
Ch. 3
Ch. 4
PAD
+58dBmv
EVEN CHANNELS
Ch. 2
Ch. 3
Ch. 4
ODD CHANNELS
+43dBmv
+43dBmv
+36dBmv
+60dBmv
6dB PAD
6dB PAD
RF
IN
RF
IN
RF
IN
RF
IN
RF
IN
RF
IN
M600
PFAM550
SUB
PHC-12U
-16dB
CHC-16U
+10dB
to
+15dB
CA-30RK550
CA-30RK550
PFAM550
SUB
PFAM550
SUB
