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Conversion Gain of mixer?

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mitgrace

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conversion gain

Dear All :

I design a mixer the imput is 100M, and the LO is 100.2MHz and LO is squart wave. How do I run Conversion Gain of mixer ? If I use the cadence spectre-RF , I use Pxf function. How to see the result ? What frequency of Conversio Gain do u see ? 200KHz ?? Thanks
 

szekit

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try pss or qpss. you should see the fundamental at 200khz (or 200.2Mhz). search for the cadence manuel on mixer simulation online.
 

vfone

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The difference of the output level (200kHz) minus input level (100MHz) represents the conversion gain of the mixer.
 

biff44

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In most applications, a square wave is not what you want to use for the LO.

A square wave has a lot of spectral content, so you are in essence folding over the noise of all those sidebands into the IF.
 

mitgrace

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Dear biff44 :

Because the LO is about 100MHz. it is divide by D-flip flop, so that the waveform is square wave, So that this is my big problems, How to correct simulation for mixer ? I read many manuel , Don't describe it ? Can you give me some suggestion ? Thnaks
 

safwatonline

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hello,
i was wondering what makes LO being square make any diffrence as far as i know LO is used only for switching and in either cases the RF is multiplied by a square wave "even with sine LO" as we dont mutiply the two signals but the LO controls the switch and also as far as i know the LO being a square is an advantage as the switching will be more ideal "faster", so i don't get what is the problem.
 

mitgrace

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Dear safwatonline :

Thanks your comment. But How do I do the simulation using spectre-RF . I see the manuel, It teach us to using port (LO , Sin type) to do conversion gain ,NF ? But it is diffent with square wave. This is my confuse point. How to solve this problem, Thanks
 

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