摘要 |
<p>A television tuning system includes UHF and VHF signal paths each tuned by a tuning voltage and coupled to a common signal path by a diplexer. So that UHF signals will be attenuated so to not cause interferences with a VHF channel signal which is selected to be viewed, the UHF filter is detuned when a VHF channel is selected. Detuning the UHF filter is accomplished by modifying the tuning voltage for the UHF filter responsive to the VHF band-switching voltage.</p> |