4 ms·

I've also been working up an idea. You can do a lot with a frontend and ADC that can be on a single board and push everything into the digital domain where boa

by edrxty 3y ago

I've also been working up an idea. You can do a lot with a frontend and ADC that can be on a single board and push everything into the digital domain where board to board connectors work better. I want to do a vhf/uhf+ dual slot modular SDR handheld that has first class data support, so no stupid AF modems to get APRS or M17.

ChuckMcM 3y ago
Pretty much. There is an interesting protocol for sending IQ data over Ethernet (VITA 49.2) which can be decoded in an FPGA and dumped into a data stream. LVDS pairs work too of course. I've got a 4MSPS ADC which is being driven by an ICE40 FPGA to generate a 1MSPS fully analytic stream. 1MHz of bandwidth isn't really good for WiFi or Bluetooth but you can easily do all of the common modulations in use by amateurs.
- edrxty 3y ago
  How are you thinking you'll structure your frontend? I've been looking at ZIF, maybe the CMX991 or similar. One thing I've also been investigating is the possibility of pushing the bandwidth way up to 10-20MHz and using a larger FPGA for DSP then conversion to PCIe. An increasing number of smaller SOCs/SOMs are supporting PCIe so that opens up interesting options like a CM4 on the low end or a Jetson Nano on the high end for all manner of shenanigans.
  - ChuckMcM 3y ago
    LNA -> band filter -> mixer -> LPF -> ADC | LO My current bodged together setup as 40/20/15/10M filters tied to a 4:1 RF switch (mini-circuits). The "easy" design is the reference design for the AD9863 (they even have layouts you can use) but I wanted to see if I could make it so that the entry level version was very inexpensive and you could add money for more capability.
    - edrxty 3y ago
      Nice, that's a good band selection. With the 9863 you could pretty much cover everything without even mixing but you'd be looking at some high end FPGAs and processors

by edrxty 3y ago

ChuckMcM 3y ago

Pretty much. There is an interesting protocol for sending IQ data over Ethernet (VITA 49.2) which can be decoded in an FPGA and dumped into a data stream. LVDS pairs work too of course. I've got a 4MSPS ADC which is being driven by an ICE40 FPGA to generate a 1MSPS fully analytic stream. 1MHz of bandwidth isn't really good for WiFi or Bluetooth but you can easily do all of the common modulations in use by amateurs.

edrxty 3y ago
How are you thinking you'll structure your frontend? I've been looking at ZIF, maybe the CMX991 or similar. One thing I've also been investigating is the possibility of pushing the bandwidth way up to 10-20MHz and using a larger FPGA for DSP then conversion to PCIe. An increasing number of smaller SOCs/SOMs are supporting PCIe so that opens up interesting options like a CM4 on the low end or a Jetson Nano on the high end for all manner of shenanigans.
- ChuckMcM 3y ago
  LNA -> band filter -> mixer -> LPF -> ADC | LO My current bodged together setup as 40/20/15/10M filters tied to a 4:1 RF switch (mini-circuits). The "easy" design is the reference design for the AD9863 (they even have layouts you can use) but I wanted to see if I could make it so that the entry level version was very inexpensive and you could add money for more capability.
  - edrxty 3y ago
    Nice, that's a good band selection. With the 9863 you could pretty much cover everything without even mixing but you'd be looking at some high end FPGAs and processors