Voltage controlled oscillator (VCO) employing nested oscillating loops

摘要

The VCO is comprised of first and second "nested" oscillating loops. The first loop includes M cascaded inverters interconnected to normally oscillate at a given fixed frequency. The second loop includes N cascaded inverters where the input of the first of the N inverters is connected to the output of one of the M inverters and where the output of the Nth inverter is coupled to the output of a different one of the M inverters, whereby at least one of the M inverters is common to the two loops, and where M and N are integers. A control voltage is coupled to at least one of the N inverters to vary its conductivity and cause the frequency of oscillation of the two loops to change.