Some materials I found (not knowing "who needs what"....

[guitar_199]

Good morning to all and I hope you are doing well.

I notice that all kinds and types hang out here. Generally they are loosely categorized as those who need help and those that can give help. Me I am trying to learn and in so doing... I try to share. I'd like to post links to two videos I found (there may be more there that are useful) that explain and even demonstrate a couple of concepts found in communications radios. I hope nobody minds.

First up, "diodes as a switch". I knew that they were in there.... I just never gave any thought to how they are doing what they do. This is a pretty neat video where it is described what is going on...and then a couple of bench experiments with lab equipment that demonstrate how it works>



Next, the concept of RF Mixing and IFs. Again, I have had the theory in my head but this explanation and demo really helps get a picture of what is going on.



I can only hope that some might find it useful....

 

[guitar_199]

If I haven't upset anybody yet.... maybe I will with this one......

He has another one on phase locked loops. Again, he follows up with bench experiments .....WITH chips......shows how the parts and pieces behave when they are NOT in a loop...(he shows the operation of the VCO, the operation of the phase detector and it's output, type 1 and type 2 phase detectors, THEN closes the loop and demonstrates how the looped circuit behaves. THEN he brings in division and divide ratios in the reference and the VCO feedback legs to achieve frequency synthesis.

This one explains a lot...and you get to see the operation.....

 

[Shadetree Mechanic]

Bump

 

[Shadetree Mechanic]

Just found this again, bump.