Hi Experts,
I am trying to setup optimization for a filter response skirts. An optimized filter skirt requires two slopping limit lines between which the filter response must pass through. Looking at optimization block, measurement s[2,1] should be below certain range of values and at the same time above certain range of attenuation values over a desired frequency range. It looks like a slopping channel through which filter skirt must pass through. How would one setup such goal condition in the optimization block using Genesys?
//RF
I am trying to setup optimization for a filter response skirts. An optimized filter skirt requires two slopping limit lines between which the filter response must pass through. Looking at optimization block, measurement s[2,1] should be below certain range of values and at the same time above certain range of attenuation values over a desired frequency range. It looks like a slopping channel through which filter skirt must pass through. How would one setup such goal condition in the optimization block using Genesys?
//RF
If i understand you correctly you are trying to set up the optimisation to define the slope of the filter skirt.
I don't believe Genesys can do this with a single line in the optimisation dialogue. All you need to do though is define a narrow band of frequencies above and below your cut-off points at which you need to provide a minimum attenuation. This figure will be your minimum stopband attenuation figure which hopefully you know.
Going with a Chebyshev topology the skirt slope is designed by the order number. With the order set the slope of the skirts will be set to a certain degree but if you need a certain level off attenuation at frequencies further away from those already defined you will need to add these in as a separate line in the optimisation dialogue.
See the attached picture
If the optimisation is struggling achieving the attenuation required you will need to consider raising the order of the filter, raising in band return loss spec or changing the topology.
Don’t forget that most physical realisations of filters have re-entrant characteristics so this needs to be considered if you need to maintain stopband attenuation over a frequencies a long way from the cut off.
Cheers
Dan