Switchless multiband filter architecture
First Claim
Patent Images
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.
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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.
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Citations
20 Claims
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1. An apparatus comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus comprising:
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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. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method comprising the steps of:
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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. - View Dependent Claims (15, 18, 19, 20)
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16. A method comprising the steps of:
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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. - View Dependent Claims (17)
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Specification