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:
Dec. 09, 2003
Filed:
Dec. 09, 1998
Lawrence M. Burns, Mountain View, CA (US);
Ravi Ramachandran, San Jose, CA (US);
3Com Corporation, Santa Clara, CA (US);
Abstract
A method and apparatus for performing an operability test on a communications system device such as a cable modem is provided. The testing method comprises the steps of providing a set of output test data to the communications system device being tested, and generating an output signal with the device in a manner that is responsive to the output test data. In the case of a cable modem, the output signal is generated by the modem's modulator. The output signal is then provided as an input to a reflective mixer which generates a reflected signal in response to the output signal and directs it back into the communications system device being tested. The communications device can then use the reflected signal to generate a set of input test data that can be compared to the output test data to check the accuracy of the device's operation. In the case of a cable modem, the reflected signal is demodulated by a demodulator at one or more frequencies, and this demodulated data can then be compared to the output test data. In one case, the testing method is controlled by a computer device running a program of instructions to carry out the aforementioned steps. The computer device can send command signals to the modulator and the demodulator to place them in a test mode. Within this mode, the computer device can command the modulator to generate a particular output signal and command the demodulator to demodulate at certain frequencies.