The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 2005
Filed:
Sep. 15, 1999
Alejandro H. Schwartzman, San Jose, CA (US);
Charles J. Naegeli, Montara, CA (US);
Alejandro H. Schwartzman, San Jose, CA (US);
Charles J. Naegeli, Montara, CA (US);
Cisco Technology, Inc., San Jose, CA (US);
Abstract
Apparatus and methods are disclosed for reducing noise leakage on the upstream channel from a cable modem. Noise leakage from cable modems, such as from a persistently enabled amplifier or other components in the modem, can accumulate on an upstream channel and reduce the overall signal-to-noise ratio of signals sent to the headend. In order to significantly reduce such noise leakage and to provide termination of the cable plant in the modem when the modem is not transmitting data, a cable modem arranged to improve its isolation is disclosed. The modem contains an upstream transmitter having a control line on which the upstream transmitter can emit a control signal. The modem also includes a switch component capable of being enabled and disabled by the control signal on the control line. The control signal from the upstream transmitter to the switch component enables the switch component thereby allowing a data signal to be transmitted on an upstream channel. The switch component includes two switches. One switch is a series switch used to enable and disable the transmission of data. Another switch is a shunt for providing termination of the cable plant. The cable modem also includes an amplifier for amplifying the data signal from the upstream transmitter before being transmitted on the upstream channel.