I think in addition to one table per language you will also need
different tables for 75m than for 20m., hihi.
Leigh/WA5ZNU
On Fri, 13 Oct 2006 1:15 am, Rein Couperus wrote:
I a working on such a scheme for PSKmail, with tables of 32k standard
words (1 for each language),
Need a Digital
: Digital Voice: Some thoughts after one week.
--- In digitalradio@yahoogroups.com, DuBose Walt Civ AETC
CONS/LGCA [EMAIL PROTECTED] wrote:
I've heard DV using LCP-10 and a 16 tone modem as well as a 39
tone modem at 1200 bps...it sounds robotic at best. But that could
have been just the systems
-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 11, 2006 3:54 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Digital Voice: Some thoughts after one
week.
The one common theme I see with much of the digital modes that require
the higher
Some more info:
I found a paper that describes some tests done with 2.4Kbps and
1.2kbps voice transmission over HF paths. It sounds like the 1.2
kbps gives useable voice quality.
I talked to a friend who had done some research for the military
back in the '80s on digital voice transmission
The WinDRM specification is very sketchy ..
Well,... you are invited to provide a better one.
but the FEC is not
described. The interleaving of the pilots and overhead data is
described but not the interleaving of the voice data.
It says This document describes the DIFFERENCE of mode
It was my understanding that the QAM-4 modulation was used for the text
transmission and you needed to use at least QAM-16 for the voice.
How many bps can you get through with QAM-4?
If LPC doesn't work at 1200 bps, then what other codec do you suggest?
Even MELP (which is a type of LPC)
voice.
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 11, 2006 2:17 AM
To: digitalradio@yahoogroups.com
Subject: [digitalradio] Re: Digital Voice: Some thoughts after one week.
Some more info:
I found a paper
: Wednesday, October 11, 2006 8:20 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Digital Voice: Some thoughts after one
week.
It was my understanding that the QAM-4 modulation was used for the text
transmission and you needed to use at least QAM-16 for the voice.
How many bps
--- In digitalradio@yahoogroups.com, DuBose Walt Civ AETC
CONS/LGCA [EMAIL PROTECTED] wrote:
I've heard DV using LCP-10 and a 16 tone modem as well as a 39
tone modem at 1200 bps...it sounds robotic at best. But that could
have been just the systems used (ANDVT/Mil-STD-188-110)
Walt/K5YFW
e: [digitalradio] Re: Digital
Voice: Some thoughts after one week.
The one common theme I see with much of the digital modes that require
the higher level of speed is that the required minimum S/N ratio hovers
around 10 db S/N. It seems to be true with DV voice, with SCAMP, and
also
It was my understanding that the QAM-4 modulation was used for the
text transmission
Negative.
Text and data can be anything from qam-4 to qam-64
FAC data (the callsign) is the only thing which is always qam-4
and you needed to use at least QAM-16 for the
voice.
Since the codecs used
The only solution to do voice exchange with a low S/N would
be to translate all the pronounced words in symbols
Exactly what i am thinking!
We need to establish a phoneme alphabet.
Then, a correlator is needed to extract those phonems from the voice
input. Each phonem should have duration
Hi Patrick and group,
I wonder if there would be much interest in this kind of DV? The main
argument was for having a high quality sounding voice in real time.
In the early 1980's, there used to be a product called HERO (Heath
Educational Robot) which allowed simple phoneme entry so that it
Glad that I was understanding that the 4-QAM was for the text part and
not voice. At least at this point of technology advancement.
Also, you had said earlier that:
Tests with a 1200 bit/sec LPC codec have been negative (bad
intellegibility).
From my understanding of the documentation for
--- In digitalradio@yahoogroups.com, Patrick Lindecker [EMAIL PROTECTED]
wrote:
I have listened some test in spanish with artificial voice reading
words. It was not too bad. The real problem is to translate voice in
symbols, in a reliable way.
Yes. There was that fairly recent QST article
From my understanding of the documentation for WinDRM, MELP
does work if the speed is at least 1,000 bps.
No. 1000 bp400ms (bit per 400 ms) or 2400 bps
This per second / per 400 millisecond mixture is confusing !
Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
Other
Oops, I forgot about that 400 ms time segment! Yes, now I see what you
mean.
Thanks for helping clarify this.
73,
Rick, KV9U
cesco12342000 wrote:
From my understanding of the documentation for WinDRM, MELP
does work if the speed is at least 1,000 bps.
No. 1000 bp400ms (bit per 400
--- In digitalradio@yahoogroups.com, Ed Hekman [EMAIL PROTECTED] wrote:
I found the specifications. The spec used for broadcast DRM can
be
found here:
http://webapp.etsi.org/exchangefolder/es_201980v020101p.pdf
The WinDRM spec can be found here:
Ed wrote:
Are there any communications engineers in this group that can
give us some idea whether a useable quality digitized voice can be
sent over a 2.5 KHz wide HF channel with SNR comparable to or less than
what is required for analog voice?
I was thinking about this today Ed. I'd
Even though I am not an engineer, we know from P-25 that digital voice
transmissions drop out before analog completely goes into the noise and
it is my understanding that the narrowest BW they use is 6.25 KHz. And
that is primarily for VHF/UHF frequencies that do not have the problems
we have
Tony wrote:
Ed wrote:
Are there any communications engineers in this group that can give
us some idea whether a useable quality digitized voice can be sent
over a 2.5 KHz wide HF channel with SNR comparable to or less
than what is required for analog voice?
I was thinking about
Even though I am not an engineer, we know from P-25 that digital voice
transmissions drop out before analog completely goes into the noise and
it is my understanding that the narrowest BW they use is 6.25 KHz. And
that is primarily for VHF/UHF frequencies that do not have the problems
we
kd4e wrote:
I am puzzled as to why one digital signal works well under poor
signal conditions and another does not.
You have to define poor conditions somehow.
It may be noise, multipath, ionospheric doppler, fading, etc. Each one
produces a different impairment, depending on the modulation
--- In digitalradio@yahoogroups.com, Tony [EMAIL PROTECTED] wrote:
Ed wrote:
Are there any communications engineers in this group that can
give us some idea whether a useable quality digitized voice can
be
sent over a 2.5 KHz wide HF channel with SNR comparable to or
less than
what
I found the specifications. The spec used for broadcast DRM can be
found here:
http://webapp.etsi.org/exchangefolder/es_201980v020101p.pdf
The WinDRM spec can be found here:
http://www.qslnet.de/member/hb9tlk/drm_h.html
Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
It is not so much that the package is different between voice and text
modes, but rather, the amount of data flowing through the link in a
given amount of time. In order to have voice transmissions with good
intelligibility and no breaks in the signal, you need a VERY robust
data link. The
--- In digitalradio@yahoogroups.com, Andrew O'Brien [EMAIL PROTECTED]
wrote:
I have been QRV on digital voice ,using WinDRM, and thought I
would offer
some rookie/newbie random thoughts.
1. This mode's performance may appear counter-intuitive for most
digital
mode operators. By that
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