[time-nuts] DIY Frequency extension for HP Agilent 53181A, 53131A or 53181A

Rick Karlquist richard at karlquist.com
Sun Feb 15 19:39:03 UTC 2009

Samuel D. [x86/CPC] wrote:
>  - How does the counter aware about the option used ? There is no
> "intelligence" on the option board, so, the counter may detect the type of
> prescaler with some pull-up or pull-down resistors somewhere.

Don't be surprised if the option is activated in software.
Therefore, even installing the genuine board may not work.
Of course, you can always build a prescaler in an external
box and feed it into the front panel connector intended for
low frequenices.  You can use the math functions on the counter
to scale the display.

Rick Karlquist N6RK

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