gain control for 100Mhz

[Jay_Diddy_B]

Hi,

If you have a DAC in your function generator, have you considered varying the reference voltage to the DAC?

This is a DC voltage and therefore much easier to deal with.

You can put a small DAC between the reference and the reference input to the main DAC to control amplitude.

Jay_Diddy_B

[Fungus]

If you have a DAC in your function generator

Does he? That's the first mystery...

[Mechatrommer]

in my country a VGC is about 15 US . in large scale it is expensive 

good luck! i have an amplifier, err an opamp as an output stage in my FG, in that price range, just an opamp, no variable control nada...

Here's a circuit I found on the web. I think it will do what you're looking for. All you need is a cheap potentiometer:

that was everything i need . thanks . plz don't hurt ur brain to much

good luck! on not hurting your brain putting that in your 100MHz FG for the masses...

[tggzzz]

If you have a DAC in your function generator

Does he? That's the first mystery...

We did eventually manage to squeeze a partial schematic out of him, and it showed a differential current source. So a DAC is a good guess.

[navidrct]

Hi,

If you have a DAC in your function generator, have you considered varying the reference voltage to the DAC?

This is a DC voltage and therefore much easier to deal with.

You can put a small DAC between the reference and the reference input to the main DAC to control amplitude.

Jay_Diddy_B

My DAC have feedback but our purpose now is that don't use that

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[navidrct]

If you have a DAC in your function generator

Does he? That's the first mystery...

We did eventually manage to squeeze a partial schematic out of him, and it showed a differential current source. So a DAC is a good guess.

I'm new in forum thing . Sorry
I'll do my best . Thanks

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[tggzzz]

I'm new in forum thing . Sorry
I'll do my best . Thanks

Making mistakes is inevitable; we all do it. As I taught my daughter, "let's make new mistakes".

Understanding and applying what's in https://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/ is relevant to more thna this forum; it is valuable in alll aspects all of life.

[navidrct]

I'm new in forum thing . Sorry
I'll do my best . Thanks

Making mistakes is inevitable; we all do it. As I taught my daughter, "let's make new mistakes".

Understanding and applying what's in https://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/ is relevant to more thna this forum; it is valuable in alll aspects all of life.

Thanks

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[krish2487]

I am guessing he is not a native english speaker...


Therein is a part of the problem. This can be addressed


The other being, lack of clarity on what,how,why he wants help with...
This part will need a certain introspection on his part and clear framing of answers to those questions.
I, myself, am not a native english speaker and I find that writing down on a piece of paper helps me articulate better.
 

[tggzzz]

This part will need a certain introspection on his part and clear framing of answers to those questions.
I, myself, am not a native english speaker and I find that writing down on a piece of paper helps me articulate better.

I - as an English speaker - find that writing down the problem, approaches, solutions, unknowns helps me a very great deal. Often to the extent that I'm able to answer my own question without bothering other people.

Of course, it does help if you know what to write down, i.e. have a clue about how to approach problem definition and problem exploration and problem solving.

[krish2487]

Touche!! :-) critical thinking and problem solving abilities are the missing part of the equation. I just did not think of them first.

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[navidrct]

Let's create topic for that. [emoji1]
What feedback resistor do u suggest?

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