Automatic Level Control Techniques for DDS-based Designs - TODAY 8PM

[Karl W4KRL]

http://www.cwtd.org/May_6-2014.html

 

"Automatic Level Control Techniques for DDS-based Designs" will be the topic
on this Tuesday's episode #68 of "Chat With The Designers" at 8pm ET on
Teamspeak.

 

Most homebrewers know that DDS boards suffer from output level roll-off due
to the sampling theorem (sinc function), as well as due to gain-product
bandwidth limitations of amplifiers used after the LPF on the DDS boards.
And sometimes that roll-off can result in as much as five times lower
voltage level at 60 MHz than at the lower frequencies. For applications
using a DDS in accurate measurement applications, designers usually correct
for this frequency-dependent level change using some sort of calibration
technique ... which can sometimes be a challenge.

 

We have developed a relatively simple ALC circuit that appears to be working
splendidly at keeping the output of the DDS-60 at a relatively constant
output level from 1-60 MHz, and we'll be discussing the circuit and
techniques in-depth, along with different approaches to calibration in
measurement instruments benefiting from constant signal source levels.

 

The whiteboard used for each episode is at
http://www.cwtd.org/May_6-2014.html ... it's somewhat under construction at
the moment, but will be completed in time for the show on Tuesday.

 

Hope you can join us

 

!73, George N2APB & Joe N2CX www.cwtd.org

 

PS: It's easy to get on Teamspeak ...
http://www.cwtd.org/TeamspeakInstructions.html 

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