[TangerineSDR] Functional Specification v 0.3

[Tom McDermott]

Hi Bill, not sure the conversion is required for HDF5, but it is required
if sending to Gnuradio, and handy for listening.

The conversion is easy in C.

-- Tom, N5EG

On Mon, May 27, 2019, 6:24 PM Engelke, Bill <bill.engelke at ua.edu> wrote:

> Tom – a question for you – are you sure it is necessary to convert the
> 24-bit I and Q to single precision floating point? When I read the Digital
> RF 2.0 documentation, I find the following:
>
>
>
> Another design decision underlying Digital RF is the requirement to
> support storing RF data in
>
> rf_data in a variety of data types. Data can be written as either complex
> or real (i.e.,
>
> single-valued) numbers. Data formats can be any data format supported by
> the HDF5 standard,
>
> from bytes to 128 byte floating point numbers.
>
>
>
> Are you referring to a different version of Digital RF?    -73- Bill, AB4EJ
>
>
>
>
>
>
>
> *From:* Tom McDermott <tom.n5eg at gmail.com>
> *Sent:* Sunday, May 26, 2019 9:08 PM
> *To:* TAPR TangerineSDR Modular Software Defined Radio <
> tangerinesdr at lists.tapr.org>
> *Cc:* Scotty Cowling <scotty at tonks.com>; Engelke, Bill <
> bill.engelke at ua.edu>
> *Subject:* Re: [TangerineSDR] Functional Specification v 0.3
>
>
>
> Hi Bill - thanks for iterating the specification.  Here are a few comments
> on 0.3:
>
>
>
> There are no paragraph numbers to  reference, and the page numbers may
> change
>
> depending on how mark-up is selected by the reader, so I'll reference the
> Title of the paragraph.
>
>
>
> General Requirements - Assumptions and Dependencies:
>
>
>
> 1. The HD may be able to be reduced to 2TB if the 20GE snapshot
> can be made while recording to the ring buffer.  2T SSD drives
> are coming down in price faster than 4T.
>
>
>
> Technical Notes
>
>
>
> I am skeptical that a SBC-based host can run HDF5 and keep up
> with the received data. My quad Core I7-3740 3.4 GHz can not
>
> keep up with 4 x 192k from one antenna (one fourth the DE
>
> requested throughput). It may be better to run HDF5 only on the
>
> snapshot that is uploaded to the Central Server. That way it
>
> doesn't have to run at real-time speed, it only needs to code a small
>
> subset of the data and can run at a much slower rate paced by how
>
> fast the upload link is.
>
>
>
> Data format.  The DE will downconvert and decimate the received
> samples. This will produce 24 bit I and 24 bit Q samples, probably 2's
> complement binary.  These will need to be converted to single
> precision floating point I and floating point Q prior to HDF5 encoding.
>
>
>  -- Tom, N5EG
>
>
>
>
>
>
>
> On Fri, May 24, 2019 at 12:40 PM Engelke, Bill via TangerineSDR <
> tangerinesdr at lists.tapr.org> wrote:
>
> Scotty - Please see attached, updated to include some of the things
> discussed at Dayton.  Next I will work on the Functional Specifications for
> the Central Control & Database system.
>
>
>
> If anyone would like me to start posting to the TAPR github or somewhere,
> please just text credentials to my mobile number, below.  I can assure
> everyone that I will not make a mess of it, having done this before.
>
>
>
> W. D. Engelke (Bill), Asst. Research Engr.
>
> Center for Advanced Public Safety
>
> Cyber Hall
>
> The University of Alabama
>
> Tuscaloosa, AL 35487
>
> Desk: (205) 348-7244
>
> Mobile: (205) 764-3099
>
>
>
> --
> TangerineSDR mailing list
> TangerineSDR at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>
>
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