The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 10, 1984
Filed:
Oct. 26, 1981
Martin Graham, Berkely, CA (US);
Rolm Corporation, Santa Clara, CA (US);
Abstract
A phase-locked loop for use in the common T1 systems. The phase relationship of the clock pulse output of a voltage controlled oscillator is determined with respect to an incoming data pulse train. If the clock signal leads the data signal, an error signal of a first polarity is applied to an integrator whose output is provided to the VCO to reduce the frequency of the clock pulse. If the clock signal lags the data signal, an error signal of a second polarity is applied to the integrator whose output is provided to the VCO to increase the frequency of the clock pulse. The logic of the circuitry is such that the output of the integrator is always either increasing or decreasing, even if there is zero phase error between the clock pulse and data pulse (i.e. the loop has infinite gain for zero error). The integrator continues to integrate in a first direction until the frequency of the clock pulses is adjusted so far that the lead is changed to a lag or vice-versa, with respect to the next data pulse.