Hewlett-packard Company

Apple Inc.

Ronald K Larson

William P Cornelius

Matthew K Herndon

John L Imperato

A system that transmits signals through a communication channel. During operation, the system receives a sequence of bits for transmission through the communication channel. While transmitting a given bit, the system determines if the given bit has the same state as the previously transmitted bit. If so, the system uses a voltage-mode driver to drive a signal through the communication channel. Otherwise, the system uses a current source coupled to the voltage-mode driver to boost the drive-level of the voltage-mode driver. Note that the current source supplies a current to the communication channel without changing the impedance of the voltage-mode driver. In this way, the present invention compensates for frequency dependant losses in the communication channel without sacrificing impedance matching and without substantially increasing power consumption.

Hybrid voltage/current-mode transmission line driver

A microwave amplitude modulation system maintains constant amplitude attenuation at very high modulation rates over a broad range of microwave frequencies in response to voltage driving signals derived from modulation signals. In the system, the video input of a shunt-type PIN diode microwave amplitude modulation system is driven by a logarithmic voltage amplifier circuit which receives the modulation signals as an input.

Voltage driven microwave amplitude modulation system

An automatic power control system compensates for temperature variable components in a broadband signal generator by providing a reference signal generating circuit that is temperature matched with an automatic level control feedback circuit. The temperature matched components are either monolithic or placed in substantial thermal contact with one another. The signals from the matched signal paths are input to a summing circuit such that the effect of any temperature variation in one path is exactly offset by the corresponding temperature variation in the other path.

Automatic control system

A method is provided which minimizes the risetime of a pulse modulated microwave signal propagated through a frequency multiplier circuit which has an input blocking capacitor. The circuit is conditioned by injecting a pulse which charges the blocking capacitor to its steady state value. When a subsequent pulse modulated microwave signal is sent through the frequency multiplier circuit, there is no delay in risetime associated with charging the blocking capacitor of the frequency multiplier circuit.

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Mountain View, CA, United States of America

Ronald K Larson