National Semiconductor Corporation

The Boeing Company

James C Braatz

Hee Wong

Shu-Ing Ju

Michael Schwartz

Rodney Alan Hughes

Tuan A Dao

A transceiver providing Fiber Channel data transfer speeds may be implemented in a lower performance process technology as a single unit, thereby reducing cost. A serializer and deserializer each having multiple lower frequency clocks are provided to obtain the equivalent of a high speed clock capable of use in Fiber Channel systems. Lower speed parallel data is converted to higher speed serial data, and vice versa. A digital frequency counter along with a phase detection circuit provides synchronization. Comma detection is provided for data word alignment.

Fibre channel transceiver

Rejection of local oscillator harmonic response is provided in a mixing circuit with a pair of harmonic gating switches serially connected to the outputs of a balanced differential switching mixer and controlled by a gate clock signal having twice the frequency of a local oscillator signal controlling the switching mixer. An aperture or duty cycle of the gate clock signal determines which harmonic is rejected or suppressed, which is preferably a third and/or fifth harmonic since response of the balanced differential switching mixer to even harmonics is negligible. The resulting simple, efficient circuit is readily integrated directly into a phase-alternating mixer structure for a chopper-direct-conversion radio.

Harmonic rejection gated-switching mixer

Growing community of inventors

Kent, WA, United States of America

James C Braatz