[time-nuts] homebrew 13 dBm distribution amplifier based on NIST design 5 to 100 MHz

Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Sep 22 01:23:15 EDT 2008


Gerhard Hoffmann wrote:
> Hi all, 
>
> after reading "A low noise 100 MHz distribution amplifier for precision metrology"
> by M. Siccardi, S. Römisch, F. W. Walls, and A. De Marchi (NIST),
> I have implemented a homebrew version of their design.
>
> Circuits, simulation & measurement data are contained in:
>
> http://www.hoffmann-hochfrequenz.de/downloads/distri.zip
>
>
> Suggestions & ideas are welcome. 1:1 board layout of the next
> iteration will be available as .pdf or Gerber.
>
>
>
>
> regards, Gerhard, dk4xp
>
>   
Gerhard

The base bias divider network needs to be improved to ensure that the 
reverse isolation isn't compromised by the divider network:
Spit R2, R7, R9 into 2 equal (330 ohm) resistors connected in series and 
bypass all the resistor junctions with 100nF X7R or NP0 caps.
Bypass the bases of Q3 and Q4 with large value tantalum electrolytics 
(or plastic capacitors) as well.


Bruce




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