[hpsdr] Status of Hermes Gigabit

[Helmut]

John, the theme intrigued me: I checked the data sheet of the internal 5V
step-down switching regulator LT3680 and did some measurements at my HERMES.
Currently the LT3680 operates with a load current of approximately 1.2A,
i.e. at  roughly 30 per cent of its specified capability. Though I guess
that further 350 mA are no big challenge for this device and no reason for
confusion.

Anyway speed needs energy. We have to live with this law, hi.

73, Helmut, DC6NY

-----Ursprüngliche Nachricht-----
Von: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von John
Marvin
Gesendet: Donnerstag, 30. April 2015 00:48
An: hpsdr at lists.openhpsdr.org
Betreff: Re: [hpsdr] Status of Hermes Gigabit

***** High Performance Software Defined Radio Discussion List *****

Thanks Helmut for the additional information. I was concerned about the
extra power, because the demand for Gigabit is kind of a chicken/egg issue,
and was wondering if it was only an issue with the internal regulator. I was
concerned by the "lab bench" comment, possibly indicating not being able to
deliver the current where it was needed, even when using an external 5V
regulated supply using J10.

There is no need right now Gigabit since the firmware supports only 384 Khz
max bandwidth per receiver (which can be stitched as is done in PowerSDR).
But the firmware source supports the possibility of turning on higher
bandwidth per receiver, which is one reason that Gigabit would be useful.
The other reason would be the future protocol where most of the DSP is done
off board. In that scenario Gigabit speeds would be a requirement.

I've been wondering if the Gigabit support is just a modification of the
existing 100Mbit support, i.e. both could be supported with the same
firmware, or if it's an either/or situation due to the Gigabit support being
a significantly different design, possibly taking too many resources to
support both speeds as originally designed based on the J13 jumper.

John
AC0ZG

On 4/29/2015 3:32 PM, Helmut wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Thanks Steve for sharing the info. No worries with HERMES. The additional
> 350 mA is only a issue for the internal 5V regulator on HERMES, but there
a
> DC-terminal in front of the power switch on the board for external 13.8V
and
> 5V supplies (J10).
>
> 73, Helmut, DC6NY
>
> -----Ursprüngliche Nachricht-----
> Von: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Steve
> Haynal
> Gesendet: Mittwoch, 29. April 2015 22:46
> An: hpsdr at openhpsdr.org
> Betreff: Re: [hpsdr] Status of Hermes Gigabit
>
> ***** High Performance Software Defined Radio Discussion List *****
>
>
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