[hpsdr] Suggesting VCTCXO oscillator

[Graham / KE9H]

Hi Glenn:

There are no current plans to respin the EXCALIBUR board.

At the time of design, the access to a 1 part per million stability
TCXO was the main determinant in the selection of the CXOH20
oscillator.

A circuit could certainly be configured as you describe.

You can inject a 10 MHz signal from pretty much any source
into HPSDR via the 10 MHz input connector on Excalibur.

Thanks,
--- Graham

==


Glenn wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi!
>
> Looking at the schematic of Excalibur, I found out that the crystal 
> oscillator is a CXOH20.
>
> http://openhpsdr.org/wiki/index.php?title=EXCALIBUR
>
> CXOH20   37 euro  +-1ppm    20mA   5V   SSB phase noise 
> -125dBc/Hz at 1kHz offset:
> http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&site=dk&keywords=CXOH20 
>
>
> -
>
> Have somebody thought about a voltage trimmed VCTCXO instead? - e.g. 
> VC-TXO-23SM-100-B:
>
> VC-TXO-23SM-100-B   8 euro   +-2,5ppm   1,5mA     3V   SSB phase noise 
> -130dBc/Hz at 1kHz offset:
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=XC1618CT-ND&itemSeq=84685641&uq=634061343209855345 
>
>
> Then a potentiometer - or a slow DA-converter can be used to trim it, 
> instead of a mechanical solution.
>
> /Glenn

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