Abstract: A silicon active analog filtering buffer apparatus and its method of operation is disclosed to receive an input signal and generates a synthesized output signal. The apparatus comprises a pulse generator for receiving the input signal and producing a sequence of delayed signal pulses in response to the input signal. A control logic circuit is connected to the pulse generator for generating scheduling on/off operation control signals. An array of switched current sources includes a number of switch means each connected to the control logic for receiving a corresponding one of the generated scheduling on/off operation control signals for shaping pre-determined waveforms. An output stage providing an amplified 15 current output for shaping to form the synthesized output signal. No complex computational procedure is necessary for the creation of the output filtered signal. Power consumption, as well as device physical dimensional characteristics are both reduced.

Abstract: A circuit for collision detect of ethernet mainly includes a comparator, a controlling logic, level adjusters, collision counters and a packed length detector. The collision counter is used to detect a collision frequency of Ethernet data transmission. When the collision detector makes any error in collision detection, the controlling logic will drive the level adjusters to adjust the collision level signal up or down to provide more accurate collision detection. An additional packet length detector is used for detecting the length of data packets, so that abnormal short packets can be detected and, if so, a collision signal can be sent in the network.

Abstract: A surrounding circuit for the local area network transceiver comprises isolation transformer, electric resistance, Diodes, transmitting circuit, transistor, electric capacitor, and input circuit; in order to slow down the rising time and falling time of the signal, the circuit can effectively improve the output signal waveform at the secondary coil of the isolation transforming and make it similar to sine wave which decreases the possibility of high frequency radiation. The circuit also provides a receiving surrounding circuit connected to the output of the transmitting surrounding apparatus which can eliminate the Common Mode Noise, has the effect of isolation, and at the same time allows the low-frequency collision signal to enter the transceiving circuit and maintains enough high input impedance.

Abstract: The present invention relates to an apparatus for transmitting and receiving Manchester coded digital data for IEEE 802.3 Ethernet/Cheapernet type local area network. The apparatus mainly comprises, an isolation transformer, a signal converter with one end connected to one side of the isolation transformer, a receiver with its input connected to the other end of the signal converter, a capacitor located in the receiver and a transmitter with its output connected to the other side of the isolation transformer whereby the isolation transformer and the capacitor may isolate the external terminals from the main circuit. Moreover, the receiver and the transmitter can be integrally formed with a controller and thus to reduce the cost.