> How long to synchronize?
TBD but one 400ms frame I would guess.
> Any PAPR differences?
The waveform has 8 x 100 baud carriers so perhaps a PAPR improvement.
- David
--
Subversion Kills Productivity. Get off Subve
A repeatable test in simulation form would be better. Also some way to
define when a version fails.
On Sun, 2014-03-02 at 17:34 -0600, Ham Radio Java wrote:
> On Sun, Mar 2, 2014 at 4:50 PM, David Rowe wrote:
>
> Key question here is - how would you test any changes?
>
>
> It
Regarding the thoughts on a rig control "server" if you will.
Bruce mentioned rigctld about which I replied currently lacks what I
believe are certain critical features, among them security, proper
handling of mutliple clients, and no sequence control for commands.
While there is little question t
...and no fading. :-)Well, actually several of us worked DX with the AOR
modems. I have a few QSLs for my effort. It was the most frustrating mode I
ever used because of the poor sync robustness.
Mel
- Original Message -
From: Ham Radio Java
To: freetel-codec2@lists.so
On Sun, Mar 2, 2014 at 4:21 PM, Bruce Perens wrote:
> I don't even know how anyone got OFDM to work with an amplifier designed
> for SSB.
If you just stay out of compression, all is well. I got to work with a
religious broadcast station on a clear frequency, and the modem was
amazing. He kept
On Sun, Mar 2, 2014 at 4:50 PM, David Rowe wrote:
>
> Key question here is - how would you test any changes?
It would not be too difficult, but I was thinking of attacking the band
edges. You could do this with another user moving into your edge, and
another user noting at which Hz the current
On 03/02/2014 03:11 PM, David Rowe wrote:
> I have a candidate waveform (i.e. modulation and coding combination) that has
> a 10dB improvement over the current FreeDV waveform.
We'd be happy with a 6 dB real-life improvement. If you can really get
10 dB that's awesome.
> + 400ms (ish) of latency
Hi,
> How is your work on LDPC going?
I've been plugging away for a few months on this, and am getting my head
around the problem. I have a candidate waveform (i.e. modulation and
coding combination) that has a 10dB improvement over the current FreeDV
waveform.
To develop this waveform I made a
On 03/02/2014 02:17 PM, Ham Radio Java wrote:
> My experience is kind of old, as I was an user of the OFDM modem by
> AOR, and without fail, I'd sooner or later get jammed off the band by
> the friendly people down south, as I could sometimes manage a whole 25
> watts.
I don't even know how anyo
Hi Steve,
Our modem is much more robust than typical Ham data modems. If we get
some interference the modem comes right back, you don't lose an over.
HF data is tricky, you require high SNRs to overcome fades or
interferers. DV is different (at least I treat it differently), the
brain can error
My experience is kind of old, as I was an user of the OFDM modem by AOR,
and without fail, I'd sooner or later get jammed off the band by the
friendly people down south, as I could sometimes manage a whole 25 watts.
Apples and Oranges probably, but the thought came to me over breakfast:
"Does FDM
On 03/02/2014 01:55 PM, Ham Radio Java wrote:
> Where I'm going with this, isn't so much interleaving, but changing
> the bit pairing of the QPSK subbands.
I think the best you can do is to distribute the golay code evenly
across all of the carriers. That would deal with frequency-selective
fadi
On 03/02/2014 01:18 PM, David Rowe wrote:
> Is interference (intentional or otherwise) by other users a problem ATM?
I've only heard one report. And the offending station was W1AW! OK, one
of the portable W1AW's run for ARRL's centennial, and no doubt a
volunteer or walk-in operator.
However, co
Where I'm going with this, isn't so much interleaving, but changing the bit
pairing of the QPSK subbands. It might be just a wash, but if moving bits
can lessen the number on which the parity checker gives up, might be an
easy thing.
For example does V! and V2 have to be togther, and if spread ap
Is interference (intentional or otherwise) by other users a problem ATM?
I haven't heard anyone mention in to date. I have seen examples (some
on my blog posts) of good robustness to some overlap by SSB signals.
Those pitch/voicing/energy are protected by FEC, the parity bits for the
FEC are at t
On March 2, 2014 12:48:33 PM PST, Ham Radio Java wrote:
>You can see I might have stopped after the first two subbands, because with
>just a 150 Hz low-power jammer I can destroy your communications.
Isn't this entirely discounting the effect of the FEC?
Also, do we really have raw codec bit
I thought I would put down on paper my thoughts about the current FDM
implementation. No performance charts or anything like that, just a binary
bit placement.
The QPSK is of course fed 2-bits, which are used to create one of four
phases to one of the sixteen subbands (carriers if you like). You m
17 matches
Mail list logo
