Design and simulation of new ten-phase ring oscillator by coupling of two identical voltage controlled oscillators

In this paper, a new configuration of ten-phase ring voltage controlled oscillator (RVCO) is introduced.The introduced oscillator is realized by coupling of two identical five-stage ring oscillators.Coupling of the identical VCOs is done by reusing some of the active devices employed in the proposed circuit without using the extra components.Stages of each core VCO are derived from the current-starved delay cell.Due to the crosswise coupling, the signals at the common mode nodes of one VCO are injected into the other, and vice versa which this interaction forces the proposed circuit to generate ten output voltages with same amplitudes and frequencies.The proposed oscillator achieves a frequency tuning range of 60 % and produces ten output signals with 36o phase difference.The proposed circuit can oscillate from 1.1 GHz to 2.05 GHz by varying the controlling voltage from 0.55 V to 0.85 V.The circuit phase noise is -99.25 dBc/Hz at 1 MHz offset frequency and its figure of merit is -184 dBc/Hz.