Hi. I would like to use the AD9434 (500 MSPS) with a variable gain front-end. The input signal is broadband with relevant content between 5 MHz and 250 MHz. The LPF before the ADC should be a 3rd or 4th order Bessel. Two channels will run in parallel so the ADL5202 dual VGA seems like a good fit.
Is there an appropriate reference design I could get started with (e.g. VGA --> Bessel LPF --> high-speed ADC)?
Are there filter design application notes or software that would help with the Bessel filter design?