I've been following development for a while too, and think I can answer
some of these questions
In the main, though, the questions can be answered by understanding the
difference between the CODEC (which is used to encode and decode voice into
bits and bytes) and the modem (which is used to encode and decode bits and
bytes onto a radio channel.)
Codec2 the codec is not finished yet, and is gradually improving.
So far there are two modems: fdmdv (which has previously been used with
different codecs) and gmskmodem (which is a work in progress and is similar
to the D*STAR modem)
There is also not going to be a product in the way you are talking about -
instead there will be one part of a suite of components which can be built
to create products.
On 5 November 2012 15:03, Thomas Kocourek <[email protected]> wrote:
> Questions like:
>
> What happens when the sender and receiver equipment drift apart in
> frequency?
>
This depends on the modem being used. With the FDMDV modem, the receiver
can track the transmitter's frequency in exactly the same way as PSK31
transmissions are tracked.
Does using FM modulation vs SSB modulation give better stability to the QSO?
>
That depends on the radio channel being used. On a local V/UHF channel I'd
imagine that FM would give a better stability. On a DX HF channel, a
signal from a standard FM transmitter would use too much bandwidth and not
be as energy efficient as an SSB-type signal.
Remember, though, that we will be sending data, not audio, so "FM" and
"SSB" won't directly be used.
> Assuming FM modulation, is the resulting RF spectrum narrower or the same
> as analog voice?
>
It can be narrower. Or it can be the same and have extra error correcting
applied. This all depends on the modem being used, but with the correct
modem we should be able to achieve narrower channel spacing than is
currently used.
> Are there plans to make the product self-tracking to mitigate question 1?
>
See the answer to Q1 - this happens already
> What hardware is supported by the product? In other words, minimum
> computer specs, interface to radio, etc.
>
Minimum computer specs can't be judged yet. First of all codec2 needs to
be completed, and then people need to spend time optimising the code to
make it run better (which means it can be used on slower computers)
The interface to the radio will depend on the modem. It could be audio
(for FDMDV-type modems,) via the 9k6 data port, or something else.
Is there a feedback mechanism established yet for the general public once
> the product is released?
>
For the codec itself, it is better to give feedback before it is released.
Encode your own voice, then decode it, and see if there are significant
problems with the sound.
For products built on the codec, that will depend on the product and the
type of feedback.
Hopefully anyone with more knowledge than me will correct any factual
errors I've made.
Dan MD1CLV
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