[sdiy] Equation for converting V PP to dBm?

[Neil Johnson]

Justin Owen wrote:

> Thanks again to everyone who chipped in on this - using Tom's  
> clearly explained working below...
>
> ...I got this: http://www.sdiy.org/juz/2164_comp_CV_VPP_01.jpg -  
> which shows CV against V PP for both predicted (via Tom's  
> calculations) and actual (via a 2164 on a breadboard).

Looks about the right shape, but without knowing your experimental  
setup its difficult to tell if the difference is due to the chip or  
the test setup.

> ...and this: http://www.sdiy.org/juz/2164_comp_CV_DB_01.jpg - which  
> shows CV against DB.
>
> Interestingly, as Andre mentioned - my measurements start to fall  
> off below approx. -40dB / 0.05 V PP - but I'm pretty sure I can  
> work on that.

What are you using to measure the input and output voltages?

> Neil's Decibel write up was also a help and worth bookmarking.
>
> http://www.milton.arachsys.com/nj71/ 
> index.phpmenu=2&submenu=2&subsubmenu=1

Broken link (its missing the '?') ...try this:

http://www.milton.arachsys.com/nj71/index.php? 
menu=2&submenu=2&subsubmenu=1

Cheers,
Neil
--
http://www.njohnson.co.uk