Hello, I simulated the filter described here. https://www.zl2pd.com/SingleSpanOsc.html
The filter simulation gives much ripple throughout the hf band. Also it does not give any notch at 48mhz as the author states. What is wrong about my simulation?
Here is a screenshot.
I'm not an oscillator type but can tell you that the author has a typo in his design. I see the same thing.
FYI: I'm not familiar with with your simulation tool but notice that it says "Linear V".
I'm not an oscillator type but can tell you that the author has a typo in his design. I see the same thing.
FYI: I'm not familiar with with your simulation tool but notice that it says "Linear V". View attachment 77665
look at the photo of the complete oscillator by the author http://www.zl2pd.com/img/SpanOsc/WideSpanOscFrontView.jpg
the little figure after the mixer shows the filter response he claims. LPF at 35mhz and a deep notch at 48mhz as well
To have a cutoff frequency at 35MHz and a deep notch at 48GHz, something has to give. Either there will be high ripple and poor return loss as in this design or a higher order filter or a combination of filters (LPF & notch).
My point was that a higher order filter may be necessary. A 5th order filter will have poor return loss and > 2dB of ripple to achieve this slope. Maybe his design can tolerate this.
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Here is the results of a 7th order elliptical. The values look reasonable but I've not run a yield or optimization.