[hpsdr] Phoenix

[Helmut Oeller]

Hi Steve,

thanks for your clarifications and your motivation. It was never my
intention to slowdown your drive and I don't want to dive deeper into a
technic and economic discussion about the concept details. You asked for
guidelines of a reliable frontend:

1. to lift the typical noise figure of the ADC around 40dB, at least
for  f>10 MHz a preamp with 20 dB gain is necessary.

2. on the other hand ADC clipping must be prevented due to too much
gain: 31dB step att like Hermes or 20 dB fix att like Mercury will help.

3. Antialiasing filtering is mandatory: LPF for 1. Nyquist. If the
concept allows undersampling, seperate BPF filters with reasonable
stopband attenuation are to provide.

73, DC6NY


Am 15.04.2023 um 16:16 schrieb ad0es:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi,
>
> One benefit that I see is that with the FFT, FIR, etc processing being
> done on the GPU/CPU as opposed to
> the FPGA the algorithms used can be quickly changed without having to
> re-program an FPGA.  This also allows
> a lot more users to be able to play with the algorithms. Few people
> have the ability to program FPGA hardware.
>
> Another that I plan to work on is diversity reception with 2 ADCs.
> With all the I/Q data sitting in the Cuda/GPU space
> at the end of the DSP pass, you could continue to process the 2
> streams for diversity.
>
> Another is the shear number of virtual receivers you can support. I
> once had 57 running in a test.
>
> I also see the possibility of doing digital mode decoding of the I/Q
> data with the Cuda/GPU.
>
> And how about Automatic Signal Classification?  Have Cuda code look
> for all the Olivia signals it can find...
>
> Where I first started the sw I was using a GTX780 which has 2304 cores.
> I did the 57 receiver test with a gtx1080 which has 2560 cores.
> But now the "standard" is more like an RTX3070 which has 5888 cores.
> Step up to an RTX3090 and get 10496 cores.
> And you can put several in the same box to double your processing power!
>
> The common denominator in this is Cuda processing.  You can do MUCH,
> MUCH more than just FFT/FIR processing
> with this combination of hardware.
>
> Steve, AD0ES
>
> On 4/15/23 6:22 AM, Helmut Oeller wrote:
>>        *Just my 2 cts: When Phil, VK6PH, presented his DFC idea at
>> the SDR
>>        Academy 2016 (HR Friedrichshafen) he spoke about a firehose to
>>        fill the total amount of digital data (1. Nquist zone) directly
>>        into a PC for processing. This is certainly an interesting
>>        approach for (presently) frequencies up to 50 MHz. But e.g.
>>        compared with HERMES I can't detect any benefit of the important
>>        RF performance as the ADC/DAC is the limiting factor
>> (IM,blocking,
>>        phase noise etc.)
>>
>>
>
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