[time-nuts] GLONASS receiver

Magnus Danielson magnus at rubidium.dyndns.org
Mon Aug 6 15:34:03 EDT 2012


Hi Sylvain,

On 08/06/2012 03:51 PM, Sylvain Munaut wrote:
> Hi,
>
>> GSM and derivates have +/- 50 ppb as frequency requirement, no time
>> requirement.
>
> Note that GSM also have the constraint that all timing / frequencies
> in the system must be derived from the same reference.
>
> This way carrier freq / symbol rate / gsm time are all linked the same way.

It's a synchronous system. It's neat how the timing of the transmission 
from the handsets is being steered (by quarter symbol solution) by the 
base-station such that they occur in the middle of their time-slots as 
being received by the base-station. The 13 MHz (actually 26 MHz or 52 
MHz in modern handsets) clock of the hand-set is steered to the 
frequency of the base-station. Thus, synthonisation and synchronisation 
can be achieved.

Cheers,
Magnus




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