Impact of VCO Topology on SET Induced Frequency Response

Laser experiments performed on two SiGe voltage controlled oscillator (VCO) circuit topologies show different output spectrums. Analytical models demonstrate that spectral response is determined by design features that impact modulated amplitude or frequency characteristic of transient signals. Further analysis of the two circuits shows the DC bias condition dependence on the topology during laser strikes, which is the main cause of the frequency and amplitude modulation of the transient output signal.