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:
Mar. 29, 1988
Filed:
Apr. 03, 1986
David L Campbell, Sunnyvale, CA (US);
Ravindra D Tembhekar, Santa Clara, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
Method and apparatus suitable for inclusion in an integrated circuit transceiver meeting IEEE 802.3 standards which detects 'collisions' so that more than one station will not simultaneously transmit over a network. The method employs a novel three-pole cyclical low-pass filter which attenuates the ac component received over the network to less than 20 mV to allow collision detection within the 900 nanosecond budget allowed by the IEEE standard. A differential operational amplifier receives the signal from the network and a collision reference voltage. The signal generated by the differential amplifier is filtered by the low-pass filter and then coupled to a high-gain comparator which acts as a zero-crossing detector. The comparator generates ECL logic signals representing the occurrence or non-occurrence of a collision. The resulting collision detector operates over a wide range without the need for field 'trimming'.