Carrier regeneration circuit for digital transmission systems

Abstract

Abstract Circuit for regenerating the carrier wave for a digitally modulated wave comprising an oscillator (17) which can be voltage-controlled through an error signal epsilon ( phi ) so as to drive the phase of the oscillator, the modulated wave being introduced to two channels, one in phase (10) and the other in quadrature (20) with the carrier, the two channels being brought together by a phase comparison device (25) which generates the error signal and a sampling clock (H1). The phase comparison device (25) operates alternately as a phase detector and as a frequency detector and, for this purpose, comprises means for selecting the points received with the aid of selection zones formed of ring portions, adjoining certain states of the constellation. The signals from the phase- and quadrature-channels serve to address a memory (26) which contains information on whether or not the point received belongs to one of the selected zones, as well as the amplitude and the sign of the error which relate thereto. The phase comparison device (25) further comprises means (28, 29) of generating the sampling clock (H1) which, in acquisition mode (not locked on) only check the base clock H for these selected zones and which, in permanent mode (locked on) check all the leading edges of the clock H in order to form the sampling clock. …<IMAGE>…

Inventors

• 👤 Sari c/o Société Civile S.P.I.D. Hikmet

Bibliographic Details