On 6/20/2015 6:25 AM, Jim Lux wrote:
This makes a good case for the "30dB/decade very close in"
Somewhat had asked about "how" close in the 30 dB/decade is good for. There is a reference about this issue. The book Edson: Vacuum Tube Oscillators has what I believe is the first published calculation of oscillator phase noise. Way before Kurakowa and Leeson. Edson has a formula that gives the 3 dB bandwidth of the oscillator signal. It's not really a bright line. This bandwidth is typically a small fraction of a Hz for the oscillators Edson is talking about. However, for an unsophisticated 10 GHz oscillator, it might amount to something that matters. I think Edson also had a paper in Proc. IRE around 1950 that might have discussed this. An interesting anecdote about Edson's book. When I got out of college I worked on RF oscillator design for Boeing Electronic Products and learned about what was then a very obscure topic called phase noise. I was no expert, but could at least say the right buzz words. At the time, the only book about synthesizers was Phaselock Techniques, which I studied extensively. It didn't have much on phase noise. In 1975, I interviewed for a job at another company designing marine radios. They wanted to replace crystals with a synthesizer. The hiring manager I interviewed with was just about at the end of his rope because most applicants couldn't even spell phase noise. At some point, I realized I had a lock on the job. My new boss taught me all about phase noise using Edson as a text book. Rick _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
