The Grass Valley Group, Inc.

Nvision, Inc.

David E Zimmerman

Birney D Dayton

A circuit for converting ECL logic level signals to CMOS logic level signals comprises a differential amplifier defining first and second current paths that are connected to a negative reference potential level. When the ECL input signal is logical zero, the first current path is non-conductive and the second path is conductive, and vice versa when the input signal is logical one. A first transistor has its base connected to the first current path, its emitter connected to a positive reference potential level, and its collector connected to the second current path. A second transistor has its base connected to the second current path, its emitter connected to the output terminal, and its collector connected to a ground reference potential level. A pull-up resistor is connected between the collector and emitter of the first transistor. The second current path includes the collector-emitter path of a third transistor, which has its base connected to the ground reference potential level and its collector connected to the base of the second resistor.

Circuit for converting an ECL signal into a CMOS signal

A tracking modulation limiter for laser diodes tracks from the output of a laser diode the maximum forward current. The maximum forward current is multiplied by a factor less than one to generate a control current representative of the maximum negative modulation for the laser diode. The control current is modulated by an input modulation signal and combined with the maximum forward current to drive the laser diode so that the drive current does not fall below threshold.

Growing community of inventors

Grass Valley, CA, United States of America

David E Zimmerman