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US 4,736,385 AGranted
Transmitter and receiver circuit
AssigneeComputer Network Technology Corporation
InventorsWarren R. Pratt, Charles R. Rogers, Dennis G. Cope
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AssigneeComputer Network Technology Corporation
InventorsWarren R. Pratt, Charles R. Rogers, Dennis G. Cope
Estimating the term…
High frequency transmitter and receiver circuits are AC coupled for party line transmission over coaxial cable where the circuits are connectable to the cable by use of stinger taps and thereby eliminate the need to interrupt service when connecting the circuits to the cable. The transmitter circuit includes oppositely polled current sources which are alternately switched to the coaxial cable via the stinger tap or to a dummy load by current switches connected to data inputs via buffer circuits. A transmit enable circuit controls the current sources to be active or inactive and to prevent unbalances from saturating either current sources. The receiver includes a high input impedance biasing network and buffer amplifier that maintain the high input impedance even when power is off. Capacitance at the tap is reduced by a capacitor drive circuit which feeds input signal back to transmitter blocking diodes and to the trunk tap. A feed ahead network, differentiating network, and another buffer amplifier form a network for recovering the transmitted signal shape regardless of distance from the transmitter. A gated amplifier restores the shaped signal to logic levels ready for conversion to non-return-to-zero data. Filter and buffer circuits restrict level detection to signals in the frequency band of the transmitter. A threshold circuit sets the carrier sense detection level and a high gain amplifier converts signals above the threshold to ECL logic levels. After conversion of the ECL logic levels to TTL logic signals, a single shot produces a DC level from the logic level carrier signal. That DC carrier sense output enables data conversion circuits and drives a gate circuit for gating the gated amplifier.
In a data communication system having a coaxial cable and transmitter and receiver circuits for transmitting and receiving data connected to said coaxial cable along the length thereof, the transmitter circuit for transmitting data comprising:
A high frequency transmitter circuit adapted for connection to a coaxial cable for transmission of digital data, the improvement comprising:
A high frequency high gain receiver circuit adapted for connection to a coaxial cable for receiving therefrom transmitted digital data, the improvement comprising:
Dependencies are inferred from the claim text.