Electronic oscillators having a plurality of phased outputs and such oscillators with phase-setting and phase-reversal capability

A multiphase electronic oscillator comprising:

• a loop of a first plurality of delay stages, the first plurality of delay stages being serially coupled to one another by a first plurality of nodes, the loop being folded to provide two concentric rings of delay stages;
• a plurality of negative-resistance elements, each element having a first output coupled to a node on the first concentric ring and a second output coupled to a node on the second concentric ring, each output of each negative-resistance element being capable of switching between a first voltage level and a second voltage level and presenting a negative resistance to a signal coupled to the output during at least a portion of a transition between voltage levels, the first and second voltage levels being opposite steady-state points, wherein each negative-resistance element has a bias to move the voltages at its outputs toward opposite steady-state points, and to switch one of its outputs to the opposite steady-state point when the other output is prompted to switch states by an external signal;
• a control chain of a second plurality of delay stages, the second plurality of delay stages being serially-coupled to one another by a second plurality of nodes, the control chain having a first terminal end and a second terminal end;
• and
• a plurality of control circuits, each control circuit having an input coupled to a node of the control chain, each control circuit being coupled to at least a node of the loop or a negative-resistance element and causing the resistance seen at a node of the loop to be modified in relation to a signal at its input.