Distortion usually increases with frequency??

[canarybird33]

Hello

Why is said that "Distortion usually increases with frequency" ?
and
what is the importance of SNR over SNDR? I mean that why they use these to concept ?

thanks:grin:

 

[chuckey]

As the frequency increases, the gain of amplifiers fall off so the negative feedback is less effective. The effect of stray capacity means that as the frequency increases the amplifier has to deliver more current to charge and discharge it rapidly. This effect is called slew rate.
Frank

 

[canarybird33]

I afraid I couldn't understand yet!!

you mean at high frequency, devices have to work on more speed and if they don't have enough slew rate it causes distortion.yes?
But is it the only reason for every devices?
what else do you think?
what about inter-modulations? what about the importance of the harmonics at high frequencies? do the have any effects?

 

[crutschow]

Inter-modulation and harmonics are the result of distortion, not the cause.
The importance of those depends upon your application.

 

[canarybird33]

why harmonics and inter-modulation are important(or appear) at high freq. but not at medium or low freq. ???

don't we have them at medium or low freq. ???

 

[FvM]

We have them at low frequencies, e.g. audio applications, too. Your assumption is wrong. at least in general.

Similary, I'm missing a clear question in your posts. Application range, devices of interest. Some of the mentioned parameters are specific to applications, others are more generally used.