[amsat-bb] Re: General Telemetry Question
dave at thejohnsonsonline.net
Mon Dec 9 06:49:33 PST 2013
In the case of FUNcube the on board sensors give their readings as n bit
values when they are interrogated. This data is agregated into a data frame
for transmission using forward error correction to improve the s/n ratio.
The problem with on board conversion is that you would have to store the
scaling/offset/logarithmic values for all channels on board, in rom.
These are usually only characterised during thermal cycling / illumination
testing etc and would have to be uploaded to the satellite rom. Not
necessarily a simple task.
It is easier to do it on the ground where we can tweak the calculation
On 9 Dec 2013 13:52, "Dave Marthouse" <dmarthouse at gmail.com> wrote:
> I noticed over the years that satellite beacon downlinks transmit their
> telemetry in a form that must be translated by a telemetry app to their
> engineering values. Since the information is transmitted from the
> why not provide the engineering values in the downlink without the extra
> step having to be done on the ground? What is the logic of doing this?
> Dave Marthouse N2AAM
> dmarthouse at gmail.com
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