| 摘要 |
<p>The bandwidth of a two-way broadband transmission system (Figure 2) is expanded by frequency stacking shared band signals. The up conversion and down conversion systems utilize matched filters (27, 37 in Figure 2), which are directly connected without a combiner, to output the stacked signal in the up conversion system (Figure 3), and without a splitter to separate the stacked signals in the down conversion system (Figure 4). A single base local oscillator signal is used to generate all of the local oscillator signals needed in the system for up/down conversion. In a coax/HFC cable system, the single base local oscillator signal is generates by a redundant local oscillator in the headend and transmitted to all of the service area nodes in the downstream signal. A comb generator (69 in Figure 4) in each node and in the headend (69 in Figure 3) generates the local oscillator signals needed for up/down conversion as harmonics of the base local oscillator signal for system wide frequency stability.</p> |
