发明名称 |
Detection of direct current in the presence of manchester-encoded signals |
摘要 |
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".
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申请公布号 |
US4734596(A) |
申请公布日期 |
1988.03.29 |
申请号 |
US19860847805 |
申请日期 |
1986.04.03 |
申请人 |
ADVANCED MICRO DEVICES, INC. |
发明人 |
CAMPBELL, DAVID L.;TEMBHEKAR, RAVINDRA D. |
分类号 |
H04L12/413;(IPC1-7):H03K5/153 |
主分类号 |
H04L12/413 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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