At+t Corp.

Robert K Montgomery

Mark Haner

Joseph H Havens

An adaptive equalizer (also called a laser interface) for generating an electrical modulating signal for use by a laser to modulate an optical data signal. The laser has a non-linear modulation response pattern such that the optical data signal comprises a primary data signal and a plurality of harmonic distortion products. The adaptive equalizer operates by generating a correction electrical signal having a frequency equal to a frequency of one of the harmonic distortion products (this harmonic distortion product is nulled by operation of the adaptive equalizer). The adaptive equalizer detects the phase and amplitude of the harmonic distortion product. Then, the adaptive equalizer phase shifts the correction electrical signal in accordance with the detected phase such that the correction electrical signal and the harmonic distortion product are conjugately matched. The adaptive equalizer amplifies the phase shifted correction electrical signal in accordance with the detected amplitude such that the phase shifted correction electrical signal and the harmonic distortion product are equal in amplitude. Then, the amplified and phase shifted correction electrical signal is combined with an electrical data signal to form the electrical modulating signal.

Adaptive equalizer for analog optical signal transmission

A carrier generator circuit for use in a modem employed in a wireless communication system is described. The carrier generator circuit includes a voltage controlled oscillator comprising an N-stage ring oscillator to generate N balanced vectors of equal magnitude and arbitrary phase difference. The carrier generator circuit also includes a phase corrector to add two of the balanced vectors to generate a sum vector and to subtract the two balanced vectors to generate a difference vector. The sum vector and difference vector have a phase difference of 90 degrees. The sum vector represents an I (in-phase) carrier signal component and the difference vector represents a Q (quadrature-phase) carrier signal component. These I and Q carrier signal components can be used to transmit and receive data signals.

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Neshanic Station, NJ, United States of America

Robert K Montgomery