Date and Real Time Clock Reference in Spectran | PPM – Aaronia SPECTRAN V6 Support Forum

#1 · 31/03/2021, 11:36

How does Spectran gets its Timing reference (Date and Real time Clock) for Time stamping IQ data when GPS functionality is not equipped in Spectran?
When Multi Spectrans are stacked together with one of them with GPS functionality, will other Spectrans (without GPS Functionality) be able to get their timing information (date and time reference) from the Spectran with GPS functionality?

#2 · 31/03/2021, 12:37

Data Time stamping is done with a precision 100MHz Clock.

In case GPS is not used, the PC date and time is synchronized with the 100MHz Clock. In order to improve Time stamping, the GPS option is used.
Spectran V6 has an PPS input which can be used to sync the internal 100MHz from an external source; typically from a GPS signal. However this is an input only, so no, you can not master from one Spectran V6 into multiple Spectran V6 slaves.

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#3 · 31/03/2021, 14:01

If you are referring to PPM signal in the Spectran block diagram, then it is shown as bidirectional. Master can be OUTPUT configured and Slaves can be configured as INPUT. Is assumption correct?

#4 · 31/03/2021, 14:41

Yes, this is how the hardware is build.

However, the output function is not available to the user. Switching between input and output by user control can permanently damage the device.

Next problem in your setup idea is to duplicate master ppm into multiple slave ppm without loosing performance. Additionally the software must identify master Spectran V6 and transfer date and time from master to the connected slaves too.

I refer to the PPM signal as PPS since it precisely outputs a rising edge every second.

#5 · 31/03/2021, 14:54

I expected this functionality based on the study of the Spectran Block Diagram (bi-directional PPM) and assumed that RTSA Software will facilitate the transfer of necessary Date and Time configuration in the slave Spectrans.

I presume you are referring to user controlling PPM as output and damaging the Spectran may be due to more than one PPM being configured as output which can cause damage.

Is it not possible to configure only One as PPM Output and others as PPM input in the Spectran Stacking. This could be controlled/ checked by RTSA Software which configures Spectrans in a cluster.

#6 · 31/03/2021, 18:04

Don't get me wrong: you point to a useful setup that the hardware could support. It is just a question to implement it in software and characterize this setup properly.

#7 · 01/04/2021, 07:57

So, I understand that PPS can be configured as output though, it may not have checks and controls when multiple Spectran are connected together in the RTSA Software and therefore you are not recommending.

As an information I want to know the Fanout, driving capacity, of the PPM port signal, that is how many input PPM ports can be connected to one single PPM output port.

#8 · 01/04/2021, 09:40

Spectran V6 PPM output is designed to drive CMOS compatible loads up to 20uA.