[chirp_devel] Mode designator for YSF?

[Mathias Weyland]

On 2023-01-10 02:32, Dan Smith via chirp_devel wrote:

Hello

I can try but don't want to claim correctness on this, nor to know how 
things should be done best. And I don't want to fight over this :-). The 
radio that I played with could be set to one of: FM, DN, VW, AMS. This 
is the interactive setting used when operating; I am not sure whether 
this also corresponds to the choice available when programming (I'm not 
using any of those digital modes). AMS is the automatic mode that picks 
the "right" one of the other tree. I find this to be a sensible choice 
for multimode repeaters, but not everybody agrees: Some people only want 
to hear the digital traffic, others only the analog traffic and they 
would set their radio accordingly. AMS is also a bit annoying since it 
changes your transmit mode to whatever was last used on the repeater. 
This is cool because you are automatically responding in the same mode 
that somebody used for calling, but then again if you want to call, you 
always have to check your settings first to ensure you are on the 
desired mode. There is, however, a setting that allows you to set the 
default for that. (E.g. RX AMS, TX always FM). I don't remember if this 
is per-channel but that works for me.

As for the DN vs. VW thing: These are different ways the voice is 
encoded into a representation of the speech model and further treated 
with the usual techniques (whitening, interleaving etc.). In DN, a voice 
data "packet" and a metdata "packet" containing the call sign, GPS 
coordinates and other stuff are transmitted in an alternating fashion. 
IN VW, there is some kind of metadata pilot package in the beginning and 
then it's just voice data all the way, thus more of the channel's 
bandwidth is used for voice data -- in fact, all of it vs. half, which 
allows them to use a better speech model and the audio quality is 
supposed to be better. The tradeoff is that a receiving station doesn't 
see the call sign on late entry or if that pilot packet got crippled. 
Hence, I believe, the names "Digital Narrow" and "Voice Wide".

All that said, I'd have to check what happens if somebody has his radio 
set in DN and some VW is incoming, or vice versa. I guess it would still 
decode but not change the current TX setting? But in any case, I always 
thought of the VW and DN to be two modes that are more or less separate 
from each other. Offering them as individual choice would reflect that. 
With the flag/extra property instead, somebody's though process while 
programming the radio would go like 'Oh yeah, I want digital on that 
channel of course... ah yeah, and I want that to be in "Voice Wide" 
[with the trade-off mentioned above]'. That would also work, I guess. 
Thus the options/schemes are:

['FM', 'AMS', 'DN', 'VW'] or
['FM', 'AMS', 'YSF'] with the extra flag for improved 'VW' voice. That 
one would work according to the aforementioned thought process, but I 
don't like it because:

- Using a checkbox for DN vs. VW imposes some kind of default and I 
don't see why chirp should suggest one over the other.
- In "Fusion",  the "F" in "YSF" refers to fusing digital and analog 
into one thing. This was one of the marketing lines when the system was 
introduced, allowing for a smooth transition to digital and all that. As 
such, it was meant to describe the whole "digital plus analog together" 
idea. Using that term to discriminate the digital part from the analog 
part thus sounds wrong... But one could use 'Digital' instead of 'YSF' 
in the second scheme.

I hope that helps somewhat

Matt