Pico Macom A860 Installation And Operation Manual page 7

A860 Manual.qxd 11/21/05 10:34 AM Page 7
Installation
A860
Signal Combining Methods
The output levels of the modulator should be the same as the output of the off-air strip amplifiers. The A860 modulators are usually
combined with either the DSP806 channel processors, or XBS series strip amplifiers. Three methods are suggested to combine strip
amplifier, modulator and processor outputs.
The C860 twenty-four channel 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. Normally, the odd channels are combined on one row while
even channels are combined on the other row of directional couplers. The combiner loss is 28-30 dB per channel. Used with an L860
distribution/launch amplifier the system's RF output provides high quality, distortion-free programming.
The CHC-16U/860 provides both signal combining and post-amplification of the headend signals. Up to 16 channels may be com-
bined using the CHC-16U/860. The combiner gain is 15 dB per channel.
The 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-30RK1000 or L860 post amplifier.
XBS – Denotes low, medium, high and superband 2 volt strip amps.
Ph: 800-421-6511 www.picomacom.com 7
Rev. 11/05