| 摘要 |
<p>A monolithic signal scrambler comprising a transmission line section (52) formed on a ceramic substrate (62), including resonant line sections (64) disposed adjacent to the transmission line path on the substrate and selectively energized to cause a predetermined signal loss through the conductive transmission line path according to the resonant frequency of the activated resonant line sections. The scrambler according to one embodiment of the present invention includes 12 resonant line sections, each tuned to approximately coincide at the preferred frequency, whereupon the loss caused by the activated resonant sections adds a significant signal loss through the transmission line path at a particular selected frequency. As a result, when used as part of a TV cable distribution system, selective activation of the scrambler provides effectively complete suppression of a selected premium signal channel while maintaining accurate control of the signal attenuation characteristics in the process. Two embodiments are disclosed, wherein the first is an active circuit, and the second is a passive, hermetically packaged filter to be installed in the line of a TV cable distribution system between the standard four-port tap and the subscriber's TV set.</p> |
