CATV network with addressable filters receiving MSK upstream signals
First Claim
1. A CATV network comprising a bidirectional trunk for connection to a head end and bidirectional distribution lines connected to the trunk to which subscriber drops can be connected for carrying wideband downstream CATV signals, the head end including means for receiving upstream signals, the distribution lines including means for transmitting said upstream signals in at least one narrow frequency band, bandpass filter means connected in the upstream direction in each of the distribution lines having passbands corresponding to said at least one narrow frequency band for blocking upstream noise and signals which may appear on the distribution lines outside of that contained in said at least one narrow frequency band, each filter means including a gate for blocking all upstream signals, means in each filter means for receiving an address signal carried downstream on said distribution lines and for opening said gate upon said gate receiving said address signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A two-way CATV network which in the preferred embodiment uses gating upstream narrowband filters in the distribution lines and/or trunks to substantially reduce upstream noise gathering. The filters sense the upstream signal energy and open in the event the energy exceeds a predetermined threshold.
-
Citations
28 Claims
- 1. A CATV network comprising a bidirectional trunk for connection to a head end and bidirectional distribution lines connected to the trunk to which subscriber drops can be connected for carrying wideband downstream CATV signals, the head end including means for receiving upstream signals, the distribution lines including means for transmitting said upstream signals in at least one narrow frequency band, bandpass filter means connected in the upstream direction in each of the distribution lines having passbands corresponding to said at least one narrow frequency band for blocking upstream noise and signals which may appear on the distribution lines outside of that contained in said at least one narrow frequency band, each filter means including a gate for blocking all upstream signals, means in each filter means for receiving an address signal carried downstream on said distribution lines and for opening said gate upon said gate receiving said address signal.
- 7. A CATV network comprising a bidirectional trunk for connection to a head end and bidirectional distribution lines connected to the trunk to which subscriber drops can be connected for carrying wideband downstream CATV signals, the head end including means for receiving upstream signals, means for carrying high frequency band signals downstream and for carrying low frequency band signals upstream along the distribution lines of the trunk, the distribution lines including means for transmitting said upstream signals in at least two narrow frequency bands, bandpass filter means connected in the upstream direction in each of the distribution lines having passbands corresponding to said at least two narrow frequency bands for blocking upstream noise and signals which may appear on the distribution lines outside of that contained in said at least two narrow frequency bands, the upstream signals being comprised of two distinct separate narrowband MSK modulated carrier signals corresponding in frequency to said two narrow frequency bands.
- 9. A CATV network comprising a bidirectional trunk for connection to a head end and bidirectional distribution lines connected to the trunk to which subscriber drops can be connected for carrying wideband downstream CATV signals, the head end including means for receiving upstream signals, means for carrying high frequency band signals downstream and for carrying low frequency band signals upstream along the distribution lines of the trunk, the distribution lines including means for transmitting said upstream signals in at least two narrow frequency bands, bandpass filter means connected in the upstream direction in each of the distribution lines having passbands corresponding to said at least two narrow frequency bands for blocking upstream noise and signals which may appear on the distribution lines outside of that contained in said at least two narrow frequency bands, each filter means including a gate for blocking all upstream signals, the upstream signals being comprised of two distinct separate narrowband MSK modulated carrier signals corresponding in frequency to said two narrow frequency bands.
Specification