DRO: encircle clockwise to satisfy Nyquist criteria

soon · Dec 1, 2004

DJ explained DRO design steps replying Gecky's post . It looks pretty simple. I found it's also easy to get S11>1 when the TLOC=40. But I found it's so difficult to get 'moving from the uper side of the smith chart to the lower as a function of frequency'. It must be the Nyquist criteria. I was required by the HB simulator to get 'clockwise encircle around 1+j0'. Tried all the length from 10 to 360 (degree in ideal line) but can't get that.

Another mystery to me is the meaning of the Osctest imepdance. I don't understand what it physically mean. Why it was set to 1.1 ohm? Sometimes I change it and then I can get S11>1 and clockwise encircle. But I still can't see oscillation in HB.

Help please! Thanks in advance.

Soon

gecky · Dec 2, 2004

Hi Soon,

DJ explained DRO design steps replying Gecky's post . It looks pretty simple. I found it's also easy to get S11>1 when the TLOC=40. But I found it's so difficult to get 'moving from the uper side of the smith chart to the lower as a function of frequency'. It must be the Nyquist criteria. I was required by the HB simulator to get 'clockwise encircle around 1+j0'. Tried all the length from 10 to 360 (degree in ideal line) but can't get that.

I have problem understanding this clock wise rotation issue too... But note: if you use the tune tool to adjust the length for the DR couple ML, chances are you'll go on forever without getting any osc.... Instead, manually change the lenght and click simulate each time... Fine tuning using the tune tool after you get osc to acheive better gain is ok. BUT, do quit the tune tool and re-sim to maje sure it works!

As for your second Qn, I can't answer...

DRO: encircle clockwise to satisfy Nyquist criteria

soon

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gecky

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DRO: encircle clockwise to satisfy Nyquist criteria

soon

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