[Dstar] D-Star Bandwidth

[Steven Samuel Bosshard (NU5D)]

Howdy again,

The dstar signal is already 6.25 kHz wide between the upper and lower
-26 dB from center (maximum or peak) points and/or  nearly 12.5 kHz wide
at between the upper and lower -60 dB down from center (maximum or peak)
points, so it is what it is.  This bandwidth transports a 2.4 kB/s voice
stream plus forward error correction (1.2 kB/s) on the voice plus a 1.2
kB/s straight thru (no fec) data stream for a thru put of around 4.8
kB/s.  I believe this is cited in the JARL and ARRL and probably WIA
dstar description documents.  Different data rates would change the
occupied bandwidth, but the signal then would no longer be dstar as we
know it.  Best regards,  Steve NU5D - ps, there are certainly many much
more knowledgeable folks about who have much keener information.  sb


vk2bzwestlakes wrote:
>
> Steven,
>
>  
>
> Thank you for the reply. I'm afraid I have no technical  knowledge of
> worth, on the D-star process. Certainly not enough to calculate a
> modulation index for the requirement. It is obvious that D-Star as we
> have had it supplied, is in a platform that is compatible with
> existing FM repeater  systems. That is of course what you have tested.
> I wonder, if it was put into a special digital transceiver of minimal
> bandwidth requirement, what that requirement would be?    Would it be
> 2.7KHz, and that is similar to a SSB transmission?
>
> Would the data rate effect the bandwidth? Would this increase it to
> your 6.25KHz? or is it 6.25KHz simply to increase the audio level in a
> wide demodulation environment?
>
>  
>
> I believe that in the future bandwidth will be a important
> consideration in all amateur communications. We are of course still in
> the 1960s with our FM transmissions. I remember that in Australia , in
> 1965 we went from 60 KHz to 30KHz in commercial networks which has
> translated to 25 KHz  allocated in the amateur service.
>
>  
>
> VK2BZ
>

-- 
A Decibel saved is a Decibel earned.....

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