Harmonic terminations in nonlinear circuits

[APPUARPITA]

Greetings,
It has been observed that in any nonlinear circuits such as , diode mixers, active mixers and in some power amplifiers(biased in CLASS-F) where harmonic terminations are such that ; for odd harmonics terminations open circuits are being used where as for even harmonics short circuit terminations are being used.If we use in reverse way what will happen ?

Can any body clarify this......., it will be useful to me very much as i am trying to design nonlinear multiplier circuits and mixers.

Regards,

APPUARPITA

 

[frankrose]

I am not an expert of this territory, but odd harmonics needs to generate square waves.
At any amplifier class the power dissipation is generated at the overlap of the transient voltage and current. Thus, if we use abrupt switching by square wave for the voltage for example, the overlap time decreases. So at class-F the efficiency of the amplifier is improved by the decreased power dissipation on the output device.

Otherwise with odd harmonics you cannot generate square wave.

And at mixers we use square waves because the conversion gain depends on the local oscillator's fundamental amplitude. The highest reachable voltage value in some cases VDD-VSS, and sometimes easy to generate this with rail-to-rail square waves. A disadvantage at mixers the odd harmonic mixing products but with output filtering they are supressable.

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Otherwise with odd harmonics you cannot generate square wave.

Otherwise with even harmonics...
Sorry for typo.

 

[mtwieg]

In the case of a class F (usually tuned to get square wave drain voltage and half-sinusoidal drain current waveforms) you end up with the inverse class F (square wave drain current, half sinusoidal drain voltage). Here's a handy chart:

https://imgur.com/a/ZKn01rp

Browse through literature and you'll see lots of references to novel "inverse" amplifier classes.