Friday, 28 June 2013
Kirisun S780 information on vocoder and standard
The radios are available on 409shop for $128, or on ebay for $140 or £90.
So here it is:
Vocoder: BBMR. Apparently developed by a Chinese university. (According to 409shop, who told me that that is what the factory told them) Must be a lower cost alternative to AMBE and RALCWI.
I have recently found out that the Chinese manufacturers have access to a chip that includes the vocoder, the Linktop LT1801A ASIC (That's Application Specific Integrated Circuit).
It includes the CPU+DSP+VOCODER+DAC+ADC apparently.
DSP: digital signal processing
DAC: digital to analog converter
ADC: analog to digital converter
It is possible that this chip is used in the radio, but its difficult to extract information from anyone in the Chinese PMR industry!
It uses 6.25KHz FDMA (so not DMR compatible)
It appears to be either dPMR with a different, manufacturer chosen, vocoder, or NDR. (NDR is actually still dPMR, but just with a certain set vocoder)
On this dPMR document, it talks about different vocoders which can be used by radios folowing the dPMR standard. The default one to use for the dPMR standard is AMBE+2, then it mentions the RALCWI vocoder, and there is something about another vocoder which will be selected by the Chinese DRA (Digital Radio Association), who are going to be going through a selection process to choose a vocoder for NDR (narrow digital radio). Finally it says that a manufacturer specific vocoder may be used.
After some further research, I have discovered that dPMR, NDR, and DCR (Japanese version), are all the same thing, but with slight variations. The second two (NDR and DCR) both conform to the dPMR standard, but have a slight variation, for example, the vocoder is different for NDR radios. They are like sub-standards, as in they follow the main standard, but specify their own vocoders.
I think this was made so that manufacturers can simply call their product an NDR radio if it uses the vocoder chosen by the DRA, or a dPMR radio if it uses the AMBE+2 vocoder.
It is possible that this radio follows the NDR standard and the vocoder used in this standard is BBMR, but this is not confirmed. I cannot even find any information on the NDR standard itself.
Which standard it follows is important because it decides whether it can communicate with other radios of that standard. Even when radios are using different vocoders, if they are both the same standard, they should be able to send text messages and status messages between one another.
If you want to see a video of it in action, there are now a few videos on YouTube, the easiest way to find them is via a search
There are also these photos from the Russian website 5radio.ru. Credit goes to them.
Check their website for a few more photos of the menus. http://5radio.ru/index.php?productID=1783
Finally, a good source of information is the yahoo group on this radio: http://groups.yahoo.com/group/S780/
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