Measurement of Phase Noise in Oscillators

The other day, I happened to sneak out some time for myself after having sent the kids to play in the neighborhood park. I made myself a hot cup of coffee and settled on the couch hoping to enjoy the silence in the house. But was it really silent?? Well... the constant tick-tock of the oscillating pendulum of the wall clock in my living room kept disturbing the silence in the air!

Oscillators, they are used in almost all electronic gadgets we have around us. Oscillators are circuits that produce continuous and repeated waveform without any input. They create an alternating current waveform with the desired frequency. However, just like the clock in my living room, oscillators are known to inherently produce phase noise. This can disturb the performance and output of the circuit, making it essential to measure the phase noise of oscillators.

Spectre RF allows you to measure the phase noise of oscillators in the Virtuoso Analog Design Environment products. It lets you characterize noise performance of the oscillators. Depending upon your circuit, you can set up the "pss and pnoise" analyses or the "hb and hbnoise" analyses in the Choosing Analyses form to measure cycle jitter (Jc), cycle-to-cycle jitter (Jcc), and amplitude modulation (AM) and phase modulation (PM) components of phase noise. This is an averaged noise measurement over one cycle of the oscillator.

To learn more, watch the Measuring Phase Noise Oscillators video on Cadence Online Support. Click the video link now or visit Cadence Online Support and search for the video under Video Library.

Related Resources

• Spectre Circuit Simulator and Accelerated Parallel Simulator RF Analysis in ADE Explorer User Guide

Note: For more information on Cadence products and services for RF design, visit www.cadence.com.

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Jommy Thomas