If the bit rate is faster, is not the signal wider as well? Would we be sacrificing a narrow band mode to achieve a faster bit rate? Digital TV looks and sounds great but the signal width is awesome! Those who think SSB can be improved and achieve a broadcast-quality signal by adding audio processors are also widening their signals on the band.
As someone else has already mentioned, it might take a complete overhaul of the vocoder, rendering everyone's current radio obsolete. However, I agree with you in some respects. I wish the audio coming from the radio were better and not so tinny-sounding. I have improved the audio quality more to my liking by adding an external speaker with good low frequency response. It makes a big difference especially as I have some high frequency hearing loss from my years in the military. 73 de Tim, AF1G ---- n2gyn <[email protected]> wrote: ============= Thank you all for you reply and comments. Let me make myself clearer. I would like to see the audio quality of D-Star be improved. To MY ears' everyone sound like a robot. I thought this was due to the low bit rate. I am NOT impressed with the digital voice mode. I want to hear a more natural sounding voice. My telephone sounds better. How could this be achieved if not by bit rate? John ==================================================== --- In [email protected], "Ted Wrobel" <twro...@...> wrote: > > Hi John, > > Not quite sure what you are thinking, but here is a brief overview of the > DStar data stream. > > The input to / output from the data processing 'module' of the radio is a > 9600 Baud stream - which equates to roughly 960 eight bit characters per > second. > > The logic of the system digitizes the voice in and passes it to the AMBE > Vocoder that compresses the data stream - a lot. > > It is the compresion by the Vocoder that is both the strength and weakness > of DStar. The compression makes a low data rate (and thus low bandwidth) > possible, but it also means that the re-constituted voice is an > approximation of the voice input. Generally the reconstructed voice is > pretty good, and given the bandwidth it is really quite remarkable. > > In any case, the baud rate of the system is fixed and cannot be modified at > any stage of the process without making the resulting stream unrecognizable > to other DStar systems. > > Note that the data rate over the internet can be much higher, but the chain > from repeater controller to / from the radio is fixed for DV comms at 9600. > > > 73 > Ted > W1GRI > > _____ > > From: [email protected] [mailto:[email protected]] > On Behalf Of n2gyn > Sent: Tuesday, August 31, 2010 16:54 > To: [email protected] > Subject: [DSTAR_DIGITAL] Bit Rate? > > > > > Most radios are sent to 8bit. Can all radio's bit rate be changed? > I believe it is the LOW bit rate that lowers the quality of d-star's audio. > Is there a sub menu in the radio's. Also can the repeater's rate be change > to a higher rate? > John >
