0
\$\begingroup\$

I'm a new user to ADS (Advanced System design). I'm trying to design a discrete Colpitt oscillator at 100 MHz in ADS. Here's my schematic: enter image description here

Now I wanna check if my circuit works properly. I watched and read some tutorial but it seems like a lot of new stuff to me. Can anyone help me to solve the problem?

\$\endgroup\$
3
  • 1
    \$\begingroup\$ your circuit won't work! place the inductor between collector and Vcc \$\endgroup\$ – Hamid R. Tanhaei Jun 20 '20 at 3:23
  • \$\begingroup\$ Yes you’re right it’s a big mistake. Thank you! \$\endgroup\$ – Henry Nguyen Jun 20 '20 at 21:52
  • \$\begingroup\$ By the way do you know how to use ADS? I’m wondering which type of simulation I should use? \$\endgroup\$ – Henry Nguyen Jun 20 '20 at 21:53
2
\$\begingroup\$

Problems in coloured boxes: -

enter image description here

  • \$\color{red}{RED}\$ box - no joining junction at cross over point hence transistor gets no bias
  • \$\color{blue}{BLUE}\$ box - inductor passes DC freely and hence connects collector to ground
  • \$\color{purple}{PURPLE}\$ box lower - Move C4 into vacant space in upper purple box and replace C4 with a short
  • \$\color{purple}{PURPLE}\$ box upper - Move C4 into that position
\$\endgroup\$
9
  • \$\begingroup\$ thank you! By the way, do you know how to use ADS? Which type of simulation should I use? \$\endgroup\$ – Henry Nguyen Jun 20 '20 at 21:49
  • \$\begingroup\$ Sorry I don’t know how to use it. I use micro cap 12. Did the fix proposals work? BTW if you are looking for a very good sim with tons of library parts, micro cap is now free (as in free beer and just as tasty). Highly recommended. \$\endgroup\$ – Andy aka Jun 20 '20 at 21:56
  • \$\begingroup\$ yes it helped. Actually I referenced this 100 MHz CB Colpitt Oscillator from the book Discrete oscillator design, Linear, Nonlinear, Transient and Noise Domains by Randall Rhea. Here's the schematic in the book drive.google.com/file/d/1N_f_R-uc-O8s287DE5zs4xJFunk1mlHi/… I don't understand the meaning of CP1, port 1 and port 2. I tried to edit the circuit and made the above mistake. Have you got any idea what those things mean? \$\endgroup\$ – Henry Nguyen Jun 20 '20 at 22:35
  • \$\begingroup\$ No, I have no idea but I wouldn’t worry. \$\endgroup\$ – Andy aka Jun 20 '20 at 23:36
  • 1
    \$\begingroup\$ @HenryNguyen I think you should raise this as a new question because others will likely want to contribute. Firstly though, go through a few questions using the search bar above to see if anyone has already answered this. \$\endgroup\$ – Andy aka Jun 21 '20 at 14:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.