cadence_choosing balun

[kogi88]

In cadence there are two ideal balun, one from rflib and other from analoglib. so which one suppose to use in designing mixer to convert single input rf to double output.
thank you

 

[Leo.cd]

use the balun in the analoglib , it will work correctly

 

[kogi88]

Thank you. it very helpful for me. now i designing for wideband mixer. so normally for fixed band, if wanna plot graph for conversion gain versus RF frequency we just vary RF freq and fixed LO freq. For my case i wanna check the stability level of conversion gain along the wideband range. Its mean that i need to vary RF freq in between the wideband range and at the same time LO freq shifted for certain (50MHz) value. - IF frequency fixed to 50MHz. There is any way to plot it? Pls help. i new for candence.

 

[Leo.cd]

if u change the LO freq, the state will change, so u can not sweep it. the parameter analysis can be used. but it will not plot the conversion gain in one graph

 

[kogi88]

So i need to plot manually one by one?

 

[Leo.cd]

Candence will plot the conversion gain of different LO freq in differernt curves(points) in one graph automatically.

 

[kogi88]

Its ok i got the solution ready have to select certain frequency points in the range of wideband and collect those points and replot necessary graph. But having one more problem, during plotting 1-dB compression point how to choose the sweep range. because different sweep range getting different 1dB point value.

 

[Leo.cd]

usually -30dBm or -40dBm is ok

 

[kogi88]

the sweep range? first i set -70 to -10 and then for second try i set for -80 to -10. the 1dB compression point value are not same.

 

[Leo.cd]

the 1dB compression point will change if change the starting point of your sweep. but it should change only a little. if it is change a lot, your circuit may have problems.
if u know where your receiver will be used, u can estimate the minimum power of the RF signal. set it to be the starting point

 

[kogi88]

ok i understand. Thank you. it really helpful alot. now i designing receiver for cognitive radio. If let say the application for tv then whats the minimum and maximum power of RF signal?

 

[Leo.cd]

It is maybe hard to say.

 

[kogi88]

can measure power gain in 1dB compression graph?

 

[Leo.cd]

I did not understand what you mean
there are two kinds of 1dB compression graph -- outpower 1dB compression and power gain 1dB compression
in the outpower 1dB compression graph, the slope in the range of linearity is the power gain
in the power gain 1dB compression graph, the value in the range of linearity is the power gain

 

[kogi88]

I did not understand what you mean
there are two kinds of 1dB compression graph -- outpower 1dB compression and power gain 1dB compression
in the outpower 1dB compression graph, the slope in the range of linearity is the power gain
in the power gain 1dB compression graph, the value in the range of linearity is the power gain

1dB compression curve is output power vs input power (RF). so its mean that any point in the range of linearity point (Pout - Pin) is power gain?

 

[Leo.cd]

I mean the slope of the graph in the range of linearity.