Switchless multiband filter architecture

• US 9,413,325 B2
• Filed: 07/01/2014
• Issued: 08/09/2016
• Est. Priority Date: 07/01/2014
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated, Time Warner Cable Enterprises LLC (Charter Communications Incorporated)
• Original Assignee: Cable Television Laboratories Incorporated, Time Warner Cable Enterprises LLC (Charter Communications Incorporated)
• Inventors: Brooks, Paul, Hamzeh, Belal
• Primary Examiner(s): Puente, Eva
• Application Number:
  US14/321,496
• Publication Number:
  US 20160006407A1
• Time in Patent Office: 770 Days
• Field of Search: 375/222, 455/333
• US Class Current: 1/1
• CPC Class Codes: H03H 7/0138 Electrical filters or coupling circuits
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence

Abstract

A cable modem is provided in a premises. The cable modem is operated in a first mode with a first upstream passband. At least one fusible link in the cable modem is caused to be blown, which in turn causes the cable modem to upgrade to a second mode with a second upstream passband, greater than the first upstream passband, without use of any switch.

Claims

1. An apparatus comprising:

an input port;

an output port;

a low-pass filter connected between said input port and said output port;

a bandpass filter;

an inverter structure connected in series with said bandpass filter, said series-connected inverter structure and bandpass filter being connected in parallel with said low-pass filter between said input port and said output port, said inverter structure in turn comprising;

a transmission line; and

an inverter connected in parallel with said transmission line by at least one fusible link without the use of any switch; and

a controller coupled to said at least one fusible link;

wherein said inverter structure, said bandpass filter, and said at least one fusible link, are configured, and wherein said controller is configurable, such that signals of a first frequency range, equal to a passband of said low-pass filter, are passed from said input port to said output port under a first condition when said at least one fusible link is intact, and such that signals of a second frequency range, equal to said passband of said low-pass filter plus a passband of said bandpass filter, are passed from said input port to said output port under a second condition when said at least one fusible link is caused to be blown by said controller.

2. The apparatus of claim 1, wherein said controller has instructions stored therein in a non-transitory manner, which instructions configure said controller to cooperate with said inverter structure, said bandpass filter, and said at least one fusible link, such that signals of said first frequency range, equal to said passband of said low-pass filter, are passed from said input port to said output port under said first condition when said at least one fusible link is intact, and such that signals of said second frequency range, equal to said passband of said low-pass filter plus said passband of said bandpass filter, are passed from said input port to said output port under said second condition when said at least one fusible link is caused to be blown by said controller.

3. The apparatus of claim 1, wherein:

said bandpass filter comprises a first bandpass filter;

said inverter structure comprises a first inverter structure;

said transmission line comprises a first transmission line;

said inverter comprises a first inverter; and

said at least one fusible link comprises a first at least one fusible link;

further comprising;

a second bandpass filter;

a second inverter structure connected in series with said second bandpass filter, said series-connected second inverter structure and second bandpass filter being connected in parallel with said low-pass filter and said series-connected first inverter structure and first bandpass filter between said input port and said output port, said second inverter structure in turn comprising;

a second transmission line; and

a second inverter connected in parallel with said second transmission line by a second at least one fusible link without the use of any switch;

wherein said controller is also coupled to said second at least one fusible link; and

wherein said first and second inverter structures, said bandpass filter, and said first and second at least one fusible links are further configured, and wherein said controller is further configurable, such that signals of said first frequency range, equal to a passband of said low-pass filter, are passed from said input port to said output port under a first condition when said first and second least one fusible links are intact;

such that signals of said second frequency range, equal to said passband of said low-pass filter plus said passband of said first bandpass filter, are passed from said input port to said output port under said second condition when said first at least one fusible link is caused to be blown by said controller; and

such that signals of a third frequency range, equal to said passband of said low-pass filter plus said passbands of said first and second bandpass filters, are passed from said input port to said output port under a third condition when said first at least one fusible link and said second at least one fusible link are caused to be blown by said controller.

4. The apparatus of claim 1, wherein said first and second frequency ranges are radio frequencies.

5. The apparatus of claim 1, wherein said first frequency range is five to forty-two MHz and wherein said second frequency range is five to eighty-five MHz.

6. The apparatus of claim 1, wherein:

said apparatus comprises a data over cable system interface standard (DOCSIS) compliant cable modem; and

said signals of said first and second frequency ranges comprise upstream signals from said data over cable system interface standard (DOCSIS) compliant cable modem into said cable television network.

7. An apparatus comprising:

an input port;

an output port;

a full-band low-pass filter connected between said input port and said output port;

N bandpass filters, N being an integer at least equal to one;

N inverters connected in series with said N bandpass filters by N at least one fusible links without the use of any switch, said N series-connected inverters and bandpass filters being connected in parallel with said full-band low-pass filter between said input port and said output port; and

a controller coupled to said N at least one fusible links;

wherein said N inverters, said N bandpass filters, and said N at least one fusible links are configured, and wherein said controller is configurable, such that signals of a first frequency range, equal to a passband of said full-band low-pass filter less a combined passband of said N bandpass filters, are passed from said input port to said output port under a first condition when said N at least one fusible links are intact, and such that signals of a second frequency range, equal to said passband of said full-band low-pass filter, are passed from said input port to said output port under a second condition when said N at least one fusible links are caused to be blown by said controller.

8. The apparatus of claim 7, wherein said controller has instructions stored therein in a non-transitory manner, which instructions configure said controller to cooperate with said N inverters, said N bandpass filters, and said N at least one fusible links, such that signals of said first frequency range, equal to said passband of said full-band low-pass filter less said combined passband of said N bandpass filters, are passed from said input port to said output port under said first condition when said N at least one fusible links are intact, and such that signals of a second frequency range, equal to said passband of said full-band low-pass filter, are passed from said input port to said output port under said second condition when said N at least one fusible links are caused to be blown by said controller.

9. The apparatus of claim 7, wherein N=1.

10. The apparatus of claim 7, wherein N=2, and wherein said N inverters, said N bandpass filters, and said N at least one fusible links are further configured, and wherein said controller is further configurable, such that signals of a third frequency range, equal to a passband of said full-band low-pass filter less a passband of one of said N bandpass filters, are passed from said input port to said output port under a third condition when one of said N at least one fusible links are intact, and another of said N at least one fusible links are caused to be blown by said controller.

11. The apparatus of claim 7, wherein said first and second frequency ranges are radio frequencies.

12. The apparatus of claim 11, wherein said first frequency range is five to forty-two MHz and wherein said second frequency range is five to eighty-five MHz.

13. The apparatus of claim 7, wherein:

said apparatus comprises a data over cable system interface standard (DOCSIS) compliant cable modem; and

said signals of said first and second frequency ranges comprise upstream signals from said data over cable system interface standard (DOCSIS) compliant cable modem into said cable television network.

14. A method comprising the steps of:

providing a cable modem in a premises;

operating said cable modem in a first mode with a first upstream passband at least in part by;

passing a first portion of an upstream input signal through a low-pass filter;

splitting a second portion of said upstream input signal into a first sub-portion passed through a transmission line and a second sub-portion passed through an inverter connected in parallel with said transmission line by said at least one fusible link, said transmission line and said inverter together forming an inverter structure, said inverter structure being in series with a bandpass filter; and

rejoining said first and inverted second sub-portions of said second portion to cancel said second portion;

causing at least one fusible link in said cable modem to blow, to in turn cause said cable modem to upgrade to a second mode with a second upstream passband, greater than said first upstream passband, without use of any switch; and

operating said cable modem in said second mode at least in part by;

passing said first portion of said upstream input signal through said low-pass filter;

passing said second portion of said upstream input signal through said transmission line and said bandpass filter, said at least one fusible link now being blown so that said transmission line and said bandpass filter are in series; and

adding outputs of said low-pass filter and said bandpass filter.

15. The method of claim 14, wherein:

said bandpass filter comprises a first bandpass filter;

said inverter comprises a first inverter;

said transmission line comprises a first transmission line;

said inverter structure comprises a first inverter structure; and

said at least one fusible link comprises a first at least one fusible link;

said step of operating said cable modem in said first mode comprises;

passing said first portion of said upstream input signal through said low-pass filter;

splitting said second portion of said upstream input signal into said first sub portion passed through said first transmission line and said second sub-portion passed through said first inverter connected in parallel with said first transmission line by said first at least one fusible link;

rejoining said first and inverted second sub-portions of said second portion to cancel said second portion;

splitting a third portion of said upstream input signal into a third sub-portion passed through a second transmission line and a fourth sub-portion passed through a second inverter connected in parallel with said second transmission line by a second at least one fusible link, said second transmission line and said second inverter together forming a second inverter structure, said second inverter structure being in series with a second bandpass filter; and

rejoining said third and inverted fourth sub-portions of said third portion to cancel said third portion;

said step of operating said cable modem in said second mode comprises;

passing said first portion of said upstream input signal through said low-pass filter;

passing said second portion of said upstream input signal through said first transmission line, said first at least one fusible link now being blown so that said first transmission line and said first bandpass filter are in series;

passing said third portion of said upstream input signal through said second transmission line, said second at least one fusible link now being blown so that said second transmission line and said second bandpass filter are in series; and

adding outputs of said low-pass filter and said first and second bandpass filters;

further comprising operating said cable modem in a third mode by;

passing said first portion of said upstream input signal through said low-pass filter;

passing said second portion of said upstream input signal through said first transmission line in, said first at least one fusible link now being blown so that said first transmission line and said first bandpass filter are in series;

splitting said third portion of said upstream input signal into said third sub-portion passed through said second transmission line and said fourth sub-portion passed through said second inverter connected in parallel with said second transmission line by said second at least one fusible link, said second transmission line and said second inverter together forming said second inverter structure, said second inverter structure being in series with said second bandpass filter;

rejoining said third and inverted fourth sub-portions of said third portion to cancel said third portion; and

adding outputs of said low-pass filter and said first bandpass filter.

18. The method of claim 14, wherein:

in said step of operating said cable modem in said first mode with said first upstream passband, said first upstream passband is a first radio frequency passband; and

in said step of causing said at least one fusible link in said cable modem to blow, to in turn cause said cable modem to upgrade to said second mode with said second upstream passband, said second upstream passband is a second radio frequency passband.

19. The method of claim 18, wherein:

in said step of operating said cable modem in said first mode with said first upstream passband, said first upstream passband is five to forty-two MHz; and

in said step of causing said at least one fusible link in said cable modem to blow, to in turn cause said cable modem to upgrade to said second mode with said second upstream passband, said second upstream passband is five to eighty-five MHz.

20. The method of claim 14, wherein:

in said step of providing said cable modem, said cable modem comprises a data over cable system interface standard (DOCSIS) compliant cable modem; and

said step of operating said cable modem in said first mode with said first upstream passband comprises passing signals through said first upstream passband from said cable modem into a cable television network;

further comprising operating said cable modem in said second mode by passing signals through said second upstream passband from said cable modem into said cable television network.

16. A method comprising the steps of:

providing a cable modem in a premises, said cable modem comprising at least one fusible link which comprises one of N at least one fusible links, N being an integer at least equal to one; and

operating said cable modem in said first mode with a first upstream passband at least in part by;

passing a first portion of an upstream input signal through a full-band low-pass filter;

passing a second portion of said upstream input signal through N inverters connected in series with N bandpass filters by said N at least one fusible links; and

adding outputs of said full-band low-pass filter and said N bandpass filters to obtain an output having a bandwidth equal to a passband of said full-band low-pass filter less a combined passband of said N bandpass filters;

causing said at least one fusible link in said cable modem to blow, to in turn cause said cable modem to upgrade to a second mode with a second upstream passband, greater than said first upstream passband, without use of any switch; and

operating said cable modem in said second mode at least in part by passing said upstream input signal through said full-band low-pass filter.

17. The method of claim 16, further comprising operating said cable modem in a third mode by:

passing a third portion of an upstream input signal through a full-band low-pass filter; and

passing a fourth portion of said upstream input signal through N-1 inverters connected in series with N-1 bandpass filters by N-1 of said N at least one fusible links; and

adding outputs of said full-band low-pass filter and said N-1 bandpass filters to obtain an output having a bandwidth equal to a passband of said full-band low-pass filter less a combined passband of said N-1 bandpass filters.