what kind of filter for Angelia board
Posted: Tue May 16, 2017 6:46 pm
Hi
I’m trying to design my “next SDR” with an Angelia board (built from component level) and some aspects of the Hermes/Angelia/Orion architectures go beyond my understanding. Particularly the input frontend
Initially, every HPSDR/Hermes/Angelia and Orion MK1 was using a combination of lpf and hpf triggered by the famous “J16” in the “Hermes Control” tab. Choosing the right lpf and hpf was giving each user the ability to configure any bandwidth bpf filter.
An 8000DLE early adopter told me that this design seems to be abandoned by Apache, and RX filters are now simple and fixed bpf filters. (literature found on Apache Labs web speak about BPF too)
- With this bpf architecture, I imagine that the TX Path LPF is not in use during RX (or does-it, to enhance the upper cutoff slope of the filter ?) Am I right ?
- Is the 8000DLE Bpf topology still controlled by the software option “Hermes Ctrl”? Yes/no ? (just insane curiosity, not an important detail for my own homebrewing)
- For which reason the Alex HPF/LPF setup screen asks for a “low” and “high” frequency limit ? (in other words, why 2 frequencies when a lpf or a hpf has only one rollon or rolloff frequency ?)
- How are equipped Angelia or Orion “200D” for the RX2 path ? bpf, hpf and a lpf “synchronized” with le tx lpf, or no filter at all? Documentation is not really clear on that point, and I tried to RTFM without finding any answer. The general “block diagram” of the Apache brochure hides all these details behind an orange square marked as “anan 100D/200D only blocks”. Published schematics don’t speak about a specific filtering in the RX2 path
- Is there any technical reason (except cost & switching simplicity) to adopt a bpf topology instead of the Alex architecture ?
I hope someone will be able to understand my rotten English and my existential questions
73’
Marc f6itu
I’m trying to design my “next SDR” with an Angelia board (built from component level) and some aspects of the Hermes/Angelia/Orion architectures go beyond my understanding. Particularly the input frontend
Initially, every HPSDR/Hermes/Angelia and Orion MK1 was using a combination of lpf and hpf triggered by the famous “J16” in the “Hermes Control” tab. Choosing the right lpf and hpf was giving each user the ability to configure any bandwidth bpf filter.
An 8000DLE early adopter told me that this design seems to be abandoned by Apache, and RX filters are now simple and fixed bpf filters. (literature found on Apache Labs web speak about BPF too)
- With this bpf architecture, I imagine that the TX Path LPF is not in use during RX (or does-it, to enhance the upper cutoff slope of the filter ?) Am I right ?
- Is the 8000DLE Bpf topology still controlled by the software option “Hermes Ctrl”? Yes/no ? (just insane curiosity, not an important detail for my own homebrewing)
- For which reason the Alex HPF/LPF setup screen asks for a “low” and “high” frequency limit ? (in other words, why 2 frequencies when a lpf or a hpf has only one rollon or rolloff frequency ?)
- How are equipped Angelia or Orion “200D” for the RX2 path ? bpf, hpf and a lpf “synchronized” with le tx lpf, or no filter at all? Documentation is not really clear on that point, and I tried to RTFM without finding any answer. The general “block diagram” of the Apache brochure hides all these details behind an orange square marked as “anan 100D/200D only blocks”. Published schematics don’t speak about a specific filtering in the RX2 path
- Is there any technical reason (except cost & switching simplicity) to adopt a bpf topology instead of the Alex architecture ?
I hope someone will be able to understand my rotten English and my existential questions
73’
Marc f6itu