[hpsdr] New Hermes 2M Board

[James Malone]

Please keep the discussion on the list!

Tnx

Wa3lbi



Sent from my iPhone

> On Jul 10, 2017, at 11:49 PM, Tony Hagen <prosdr at gmail.com> wrote:
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hello Helmut,
> 
> Please keep the discussion on the list ... very interesting even we cant be an active participant
> 
> 73
> Tony
> 
> .........................................
> -----Original Message----- From: hpsdr-request at lists.openhpsdr.org
> Sent: Tuesday, July 11, 2017 3:28 AM
> To: hpsdr at lists.openhpsdr.org
> Subject: Hpsdr Digest, Vol 137, Issue 7
> 
> Send Hpsdr mailing list submissions to
> hpsdr at lists.openhpsdr.org
> 
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> or, via email, send a message with subject or body 'help' to
> hpsdr-request at lists.openhpsdr.org
> 
> You can reach the person managing the list at
> hpsdr-owner at lists.openhpsdr.org
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Hpsdr digest..."
> 
> 
> PLEASE change your subject line in any replies to this digest to reflect the actual subject!!!  Also please trim quotes of previous messages to a minimum necessary to maintain context. Remember: if you post using fancy rtf or html, it will not be read by Digest recipients without a big effort. We all thank you for this thoughtfullness.
> 
> Today's Topics:
> 
>  1. Re: New Hermes 2M Board (Larry Gadallah)
>  2. Re: New Hermes 2M Board (Helmut Oeller)
>  3. Re: New Hermes 2M Board (n3evl)
>  4. Re: New Hermes 2M Board (ad0es)
>  5. WG:  New Hermes 2M Board (Helmut Oeller)
>  6. Re: WG: New Hermes 2M Board (H.A. Meijer)
>  7. Re: WG: New Hermes 2M Board (Jim Sanford)
>  8. Re: New Hermes 2M Board (Doug Ronald)
>  9. Re: New Hermes 2M Board (Shirley M?rquez D?lcey)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sun, 9 Jul 2017 20:35:32 -0700
> From: Larry Gadallah <lgadallah at gmail.com>
> To: Helmut <dc6ny at gmx.de>
> Cc: HPSDR Lists <hpsdr at lists.openhpsdr.org>
> Subject: Re: [hpsdr] New Hermes 2M Board
> Message-ID:
> <CAPtFaQv5i7nZ6y3s4hEL7DNu0z5vdds1HL9=5YQp2efOp8hdsg at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
> 
> Hi Helmut:
> 
> Thanks for your comments. I think point 1 is quite a bit more complex
> than we can address on our e-mail list, but another difference is that
> in most cases, we amateurs are dealing with analog modulation schemes,
> whereas virtually all cellular systems are now digital, which does
> reduce the required dynamic range of a receiver. Nonetheless, I think
> we agree that current generation ADCs are sufficient to the task, if
> that task is emulating a conventional analog HF radio. Personally, I
> am intrigued with the possibilities of multiple simultaneous
> receivers, wideband or spread-spectrum modulation techniques (albeit
> most are not legal in the amateur services at this time) and so on;
> implementing these would involve less decimation and process gain, and
> hence would push the ADC dynamic range requirements higher.
> 
> For point 2, I should have made it clear that, yes, I was first
> addressing frequency stability, which is not the same as phase
> noise/jitter. Of the two, I agree that phase noise/jitter is more
> important for dynamic range performance. Poor frequency stability is
> just annoying, and should be less difficult to solve than getting
> better jitter performance.
> 
> Cheers,
> 
>> On 9 July 2017 at 14:35, Helmut <dc6ny at gmx.de> wrote:
>> Hi Larry,
>> 
>> I agree with you in a lot points, but would like to correct two items:
>> 
>> 1. 16 Bit, 130 Msps ADCs are more than sufficient for ham radio applications
>> and beat most analogue radios. The typical 100 dB dynamic range refer to the
>> entire Nyquist zone. You have to add the process gain for narrow
>> band/channel operation. Cellular systems- in particular the new 5G- operate
>> at frequencies from 0.8 to 39 GHz and they all need an analogue up/down
>> conversion into the 'digital' baseband. This architecture limits the dynamic
>> range, not the 16 Bit ADC at the IF.
>> 2. Don't mix frequency stability over some hours with jitter. HPSDR sampling
>> oscillators are VCXOs and PLL-disciplined from a central 10 MHz reference.
>> Every designer knows that too much jitter of the sampling oscillator will
>> reduce the dynamic range of the ADC performance. A typical phase noise of
>> -152 dBc/Hz at 10 kHz offset is fine. Long before Mr. Sherwood and others
>> recognized this fact, Walt Kester of Analog Devices pointed to the jitter
>> influence in his tutorials.
>> 
>> 73, Helmut, DC6NY
>> 
>> 
> 
> 
> 
> -- 
> Larry Gadallah, VE6VQ/W7                          lgadallah AT gmail DOT com
> PGP Sig: B5F9 C4A8 8517 82AC 16B6  02B6 0645 69F0 1F29 A512
> 
> 
> ------------------------------
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/