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Design >> RF Design >> Mixer Noise Folding
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Message started by aaron_do on May 22^nd, 2008, 7:44am

Title: Mixer Noise Folding
Post by aaron_do on May 22^nd, 2008, 7:44am

Hi all,

I simulated a mixer using pss and pnoise analysis and by changing the number of sidebands, I was able to see the effect of noise folding. What i observed was the noise folding seems to have a negligible effect except for the image frequency which can be cancelled off later anyway.

So my question is, is this true in general, or is it just simulation, or is it just my mixer?

thanks,
Aaron

Title: Re: Mixer Noise Folding
Post by pancho_hideboo on May 22^nd, 2008, 5:23pm

aaron_do wrote on May 22^nd, 2008, 7:44am:

I simulated a mixer using pss and pnoise analysis and by changing the number of sidebands, I was able to see the effect of noise folding. What i observed was the noise folding seems to have a negligible effect except for the image frequency which can be cancelled off later anyway.
So my question is, is this true in general, or is it just simulation, or is it just my mixer?

It depends on mixer scheme. If your mixer is oriented to linear multiplier rather than up/down mixer, linearity of local signal will be good.
So large amplitude of higher order harmonics of local are not generated in mixer.

Or just your local signal's amplitude is small or its waveform is sinusoidal so that it does not include or generate higher order harmonics of local.
Try increase amplitude of local or feed rectangular pulse as local.