Description:
The original QISO still provides the brute force isolation for the most complex headend multiple channel line-up problems at the master headend. Originally designed as a single-channel high level amplifier, the QISO has shown practical uses as an active splitter operating with multiple channels in the 30 to 35 dBmV output range depending on channel loading.
When an operator was faced with serving multiple systems from a single headend, standard CATV splitters and combiners were employed to route processor and modulator outputs to their respective launch destinations (each community served). The low isolation of these splitters and couplers provided the signal feedback path for channels used in one community to create co-channel on different local channels on the same frequency in the other communities served from the common headend. With the internal isolation of the push-pull hybrids and the well-matched directional couplers of QISO, the feedback path is eliminated.
All four ports of each amplifier are padded to provide unity gain (or 18 dB gain) to each output port. The values may be changed to provide the exact level to each headend combiner. This allows one adjustment at the output of the modulator or processor to set the correct level in every channel line-up. All the SXP pads are accessible from the front of the rack should the user wish to alter the loss or gain at any or all four output ports.
The standard QISO is powered only by +24 volts DC with less than 10 millivolts of AC ripple from battery or regulated power supply sources. An external DC powering source was chosen to power the amplifier because of the dense environment in the headends and the difficulty of providing power outlets. An AC-powered model is also available for systems that do not wish to provide DC powering systems. |
Features:
 Eases multiple channel line-ups
Blocks all feedback paths
50 dB port-to-port isolation
Loop-through input coupler
Hybrid output on each port (4)
Pad for each output port (4)
Unity Gain Splitting Function
DC Powered for reliability
550, 750 & 870 MHz Models |
