Frequency Multipliers and Dividers

[faisal]

hi
Plz mention the logic used behind analog frequency multipliers and dividers.
What are the disadvantages of using frequency multipliers and dividers in the microwave range.
Regards

 

[bouchy]

Hi Faisal,

1- frequency multipliers are used as signal generation technique, permeting one to abtain and utilize the harmonics of a fundamental frequency technique, meaning if your input frquency is "f" you can get 2xf or 3xf ...

2- one of the approches that is been used for analog divider and multiplier is gilbert cell multiplier, there is a lot of informations on this subjet on the internet.

3- at microwave frquency you can use either FETs, diode(varactor or varistor) or HEMPT... the idea here is simple:
source(Zs)--> input matching circuit(Filter) --> FET --> Output matching circuit(Filter)--> load (Zl)

the input filter prevents the output power at freq 2f from propagating back to the source. similarly, the output filter is necessary to ensure the power from the external source at freq f does not propagate beyound the FET and become absorbe by the load.

4- freq multiplier are predominantly employer in mmwave system as local oscillators, lower freq multiplier are still usefull. for example, they may serve as signal processing components in some frequency synthesizers.

one of the disadvantages of the frequency multiplier is the degradation of the inpuit signal noise properties.


good luck
bouchy