Boris Spokoinyi

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60 GHz Synthesizer

One of our past projects is a 57 GHz - 64 GHz frequency synthesizer with an on-board crystal reference (CVHD-950-50) and an external reference input. Phase noise is -111.5 dBc/Hz at 1MHz, and RMS jitter is 2.8º, or 0.13ps.


Opto-Electrical converter

For this project we have done modeling of a 10Gbps Opto-Electrical system in Agilent ADS. The system consists of a laser diode, photo diode, amplifiers and interconnects. Models of the active components were generated for ADS and validated according to spice models and datasheets. Interconnect analysis was performed in Ansys HFSS (full 3D EM simulation) and ADS Momentum (2.5D EM). Time-domain reflectometry (TDR), S-parameter and Eye-diagram simulations were performed. The simulations showed the client where the problems are in the design. TDR simulation showed missmatch locations. S-parameter simulation showed 3-dB bandwidth, matching losses, and group delay ripple. Eye-diagram simulation showed AM/PM noise conversion, amplitude noise, reflections due to missmatch, and ultimatly the bit error rate. 


The Eye-diagram for whole system, after suggested improvements:


Example TDR measurements from one of the connector vendors (very close to what was simulated in ADS/HFSS):