[TangerineSDR] Functional Specification v 0.3

Tue May 28 11:01:58 EDT 2019

FWIW, I had no trouble capturing 4 x 384 kHz slices with HDF5 on an older i7 laptop with SSD.

On May 28, 2019, 10:58 AM, at 10:58 AM, "Engelke, Bill via TangerineSDR" <tangerinesdr at lists.tapr.org> wrote:
>Tom – let’s talk more about the throughput issue. As I mentioned
>before, I am working right now on a way to do some benchmarking to
>start gauging what is possible.  I have a related question for you:
>
>
>-          On your quad core I7, have you narrowed down where the
>bottleneck is?  There have been some discussions that a rotating hard
>drive might not be able to keep up with the data rate, no matter what
>format is used.  (Something else I am going to test). It is quite
>possible that the compute time to put the data out as HDF5 might be the
>smaller part of the time budget, and disk writing the larger.
>
>-          At today’s prices, a 2 TB or 4 TB SSD is a budget buster,
>but this might not be the case in 2024.
>
>Any thoughts?  I am building a crude prototype to see if I can save
>multiple channels off a Red Pitaya using HDF5 (Digital RF actually, but
>it uses HDF5), and compare throughput using both spinning drive on USB3
>and SSD. -73- Bill
>
>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<mailto: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
>
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>
>
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