Larry D Morrison

US Patent:

48412570, Jun 20, 1989

Filed:

Mar 28, 1988

Appl. No.:

7/173799

Inventors:

Larry R. Morrison - Bountiful UT
Vaughn J. Jenkins - Bountiful UT

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

H03D 1300
H03L 708

US Classification:

331 26

Abstract:

A high-speed sample and hold phase detector for clock and data recovery systems is provided with a differentiating circuit coupled to a source of coded input data signals to provide bi-level differentiated output sampling pulses which are applied to a high-speed transformer. The output of the high-speed transformer is coupled to a high-speed fullwave diode bridge rectifying circuit whose output provides the error signal for the clock and data recovery circuit. The transformer is provided with a secondary winding having a center tap connected to a bi-level clock having clock signals whose rate is at twice the data rate. The D. C. error signal voltage amplitude is proportional to the phase difference between the clock signal connected to the center tap of the secondary winding of the transformer and the differentiated sampling pulses. The sampling pulses are employed to sample the clock signal which provides higher stability and enhances noise reduction.