- #1

Tom48

- 37

- 0

Hi,

as I am in need of Low- and Highpass filters i would like to simulate my circuit using LT-Spice.

I hope that i can get optimal caps and coils values like that.

So i simply started to build my pi-network lowpass filter in LT-Spice and got the simulation results (please check the picture in the attachement)

On my board i have a SMA connector, that ouputs the RF-Signals of an antenna mux and that same SMA connector is also used for the circuit board's supply voltage of 9V.

So now i need a Lowpass filter for the DC supply and a Highpass filter for the RF-Singnals.

I would like to simulate this in Spice, however I am not sure how to approach.

E.g. I am not sure what frequencies should pass for the DC supply and where to start blocking? (Lowpass)

For the RF-Signals, i need 860-870MHz to pass. (Highpass)

What are the typical values to start with?

(please check attachement for my filter structure and first approach to simulation, i started with a lowpass filter for the DC supply)

In Spice i made an AC analysis :

AC Amplitude: 10V

points per octave= 100, start frequency= 1Hz, end frequency=200MEG

Also I am think there's more about this simulation, i guess i also somehow should model the load etc.?

I would like to be able to estimate the values of my filters using simulation but I am way too new in this field so i hope you can help me.

I appreciate every little hint, explanations and links to further information! :)

Thank you in advance! :)Kind regards, Tom.

as I am in need of Low- and Highpass filters i would like to simulate my circuit using LT-Spice.

I hope that i can get optimal caps and coils values like that.

So i simply started to build my pi-network lowpass filter in LT-Spice and got the simulation results (please check the picture in the attachement)

On my board i have a SMA connector, that ouputs the RF-Signals of an antenna mux and that same SMA connector is also used for the circuit board's supply voltage of 9V.

So now i need a Lowpass filter for the DC supply and a Highpass filter for the RF-Singnals.

I would like to simulate this in Spice, however I am not sure how to approach.

E.g. I am not sure what frequencies should pass for the DC supply and where to start blocking? (Lowpass)

For the RF-Signals, i need 860-870MHz to pass. (Highpass)

What are the typical values to start with?

(please check attachement for my filter structure and first approach to simulation, i started with a lowpass filter for the DC supply)

In Spice i made an AC analysis :

AC Amplitude: 10V

points per octave= 100, start frequency= 1Hz, end frequency=200MEG

Also I am think there's more about this simulation, i guess i also somehow should model the load etc.?

I would like to be able to estimate the values of my filters using simulation but I am way too new in this field so i hope you can help me.

I appreciate every little hint, explanations and links to further information! :)

Thank you in advance! :)Kind regards, Tom.