Hello, why i have to wait for 100ms ? ONE HOUR AND HALF, ltspice

Thread Starter

michael1978

Joined Jun 29, 2014
309
Hi, i start to learn ltspice, so i make on foster seeley, and i have to whait one hour and half for transien 100m, can be something faster thanks.
 

Audioguru

Joined Dec 20, 2007
11,249
I cannot convert the TXT file to an ASC file type.

Michael, please post your schematic of the ASC file. On the other website you had the timebase in ".TRAN" set to see radio frequencies instead of the 1kHz modulation frequency. I showed you how to set ".TRAN". Then you said, "it takes one hour and 30 minutes" without saying the the simulation takes the long time. The thought my reply delay was one hour and 30 minutes because I was busy chatting on other forums.
 

Thread Starter

michael1978

Joined Jun 29, 2014
309
I cannot convert the TXT file to an ASC file type.

Michael, please post your schematic of the ASC file. On the other website you had the timebase in ".TRAN" set to see radio frequencies instead of the 1kHz modulation frequency. I showed you how to set ".TRAN". Then you said, "it takes one hour and 30 minutes" without saying the the simulation takes the long time. The thought my reply delay was one hour and 30 minutes because I was busy chatting on other forums.
here is our foster seeley
foster seeley.png
 

Audioguru

Joined Dec 20, 2007
11,249
You are shorting C2 directly to the +12V power supply instead of connecting C2 to the output (collector) of the transistor.
 

Bordodynov

Joined May 20, 2015
2,871
Adding a separating transformer to the output (in order to exclude a constant component) requires a large calculation time T> RLoad * Cd * 10.If you reconcile with the constant component (meaning that in the real scheme it will be excluded), then it is enough to calculate several ms.By the way.Large distortions are associated with a large modulation factor.Because of this, the gain of the transistor varies greatly from the frequency (the limiter also did not help).I specified (tuned to resonance) the capacitors.
 

Thread Starter

michael1978

Joined Jun 29, 2014
309
Adding a separating transformer to the output (in order to exclude a constant component) requires a large calculation time T> RLoad * Cd * 10.If you reconcile with the constant component (meaning that in the real scheme it will be excluded), then it is enough to calculate several ms.By the way.Large distortions are associated with a large modulation factor.Because of this, the gain of the transistor varies greatly from the frequency (the limiter also did not help).I specified (tuned to resonance) the capacitors.
Hi, and what you think to do?
 

Bordodynov

Joined May 20, 2015
2,871
You are not making a radio, instead you are simulating the detector of a radio.

I used an online LC resonance program to tune the LC circuits and changed a few things controlling the Sim program:
Audioguru,
Your circuit variant works far from resonance.You have not taken into account the parasitic capacitance of the transistor (5pf) and the large capacitances of Schottky diodes (100-200pF).I tried to calculate capacitances using standard formulas, but I did not achieve a resonance, and so I just picked them up in the analysis of AC.It is easy to check if resonance is working in the first stage.Look at the signal on the collector in your and my version of the circuit.Note that I also used the limiter.Also see the peak to peak of 1 kHz at the output.
 
Top