LC oscillator sensitivity analysis

jlarkin · 2020-03-04T16:29:11+00:00

I'm designing a 125 MHz triggered LC oscillator. It's sufficiently nonlinear that I need to Spice it in transient/time domain mode. I want to explore frequency sensitivity to component values, supply voltages, stuff like that. But how to measure frequency accurately? Cursoring one cycle of oscillation on the screen is pretty crude. I guess I could use a delay line to compare the time of one edge to the previous one, essentially zoom the period. Or just note the absolute time of the zero cross of the 100th edge, and calculate from that. Analyzing oscillators in time domain is always tedious. I'm running this at 1 ps steps, so the sim runs are slow even before I try to measure frequency. Running with the LT Spice defaults does obviously weird things. Any suggestions? -- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"

Mar 04, 2020 24 Replies

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Joe Gwinn 6 years ago

There is a very good LCR meter from a Taiwanese source, that appears to have been the real manufacturer of the prior generation of a product from IET Labs, the inheritor of the General Radio line of instruments. Der EE DE-5000 is the OEM version of the discontinued IET Labs DE-5000. The IET Labs manual for the Der EE version is identical. The design originated with GR. I personally own a DE-5000, bought here:

Warning: Early models were vulnerable to mistakenly installing the

9-volt battery backwards.

Joe Gwinn

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John S 6 years ago

The manual looks great. The only thing it does not include is an estimate of battery life. Do you have any info on that from your personal experience?

The down side of this instrument is that 4 screws need to be removed to replace the battery, but if the battery lasts for a long time (several months) it might not be so bad.

Thanks, Joe.

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sroberts6328 6 years ago

Borrowed one of these once, from A&H, as their office is forty minutes from Campus. Also got a factory tour...

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Steve

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John S 6 years ago

Great! Send it to me. I'll pay the shipping charges.

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Joe Gwinn 6 years ago

Welcome.

I don't know the battery life, but I have not yet had to replace it.

Replacing the battery is pretty fast.

Joe Gwinn

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