Nov 9, 2013 #1 A AAOAA Junior Member level 2 Joined Oct 31, 2013 Messages 20 Helped 0 Reputation 0 Reaction score 0 Trophy points 1 Activity points 150 Dear all, I have the gain @100Khz in bode plot almost=0dB, while the actual gain= 20 log(Vout/Vin)=20 log(3/0.005)= 55.56dB (from the transient vales) Could someone please explain why I have this weird bode plot gain reading? Regards
Dear all, I have the gain @100Khz in bode plot almost=0dB, while the actual gain= 20 log(Vout/Vin)=20 log(3/0.005)= 55.56dB (from the transient vales) Could someone please explain why I have this weird bode plot gain reading? Regards
Nov 9, 2013 #2 D dick_freebird Advanced Member level 7 Joined Mar 4, 2008 Messages 8,988 Helped 2,333 Reputation 4,683 Reaction score 2,520 Trophy points 1,393 Location USA Activity points 71,585 Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop.
Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop.
Nov 9, 2013 #3 crutschow Advanced Member level 6 Joined Feb 22, 2012 Messages 4,469 Helped 999 Reputation 1,996 Reaction score 1,129 Trophy points 1,393 Location Colorado USA Zulu -7 Activity points 25,336 I believe it's because your formula for generating the value of R3 only works in the transient mode.
Nov 9, 2013 #4 A AAOAA Junior Member level 2 Joined Oct 31, 2013 Messages 20 Helped 0 Reputation 0 Reaction score 0 Trophy points 1 Activity points 150 Could you tell me please, what do you mean by this? dick_freebird said: Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop. Click to expand... - - - Updated - - - - - - Updated - - - """I believe it's because your formula for generating the value of R3 only works in the transient mode""" Here is R3 behaviour, I think its fine. Attachments Sensor.jpg 82.4 KB · Views: 82
Could you tell me please, what do you mean by this? dick_freebird said: Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop. Click to expand... - - - Updated - - - - - - Updated - - - """I believe it's because your formula for generating the value of R3 only works in the transient mode""" Here is R3 behaviour, I think its fine.
Nov 9, 2013 #5 keith1200rs Super Moderator Staff member Joined Oct 9, 2009 Messages 10,865 Helped 2,065 Reputation 4,130 Reaction score 1,596 Trophy points 1,403 Location Yorkshire, UK Activity points 57,270 You cannot expect a gain of 2000 at 100kHz from the LT1037. Keith
Nov 9, 2013 #6 FvM Super Moderator Staff member Joined Jan 22, 2008 Messages 52,478 Helped 14,756 Reputation 29,794 Reaction score 14,120 Trophy points 1,393 Location Bochum, Germany Activity points 298,338 Bad habbit of cross posting. I believe it's because your formula for generating the value of R3 only works in the transient mode. Click to expand... No, it does work (although you can't derive this from the transient waveforms). The simulation however doesn't measure the OP "gain". It measures V(out) in dB which is OP gain multiply attenuation by the bridge modulation factor multiply V(in). Last edited: Nov 9, 2013
Bad habbit of cross posting. I believe it's because your formula for generating the value of R3 only works in the transient mode. Click to expand... No, it does work (although you can't derive this from the transient waveforms). The simulation however doesn't measure the OP "gain". It measures V(out) in dB which is OP gain multiply attenuation by the bridge modulation factor multiply V(in).
Nov 9, 2013 #7 A AAOAA Junior Member level 2 Joined Oct 31, 2013 Messages 20 Helped 0 Reputation 0 Reaction score 0 Trophy points 1 Activity points 150 keith1200rs said: You cannot expect a gain of 2000 at 100kHz from the LT1037. Keith Click to expand... I didnt expect it 2000 at all, but my question was why the bode plot doesnt show the right gain (~0dB istead of 55dB)?
keith1200rs said: You cannot expect a gain of 2000 at 100kHz from the LT1037. Keith Click to expand... I didnt expect it 2000 at all, but my question was why the bode plot doesnt show the right gain (~0dB istead of 55dB)?
Nov 9, 2013 #8 keith1200rs Super Moderator Staff member Joined Oct 9, 2009 Messages 10,865 Helped 2,065 Reputation 4,130 Reaction score 1,596 Trophy points 1,403 Location Yorkshire, UK Activity points 57,270 I don't know why you think your gain is 55dB in the transient analysis. You are putting 1V peak in and getting around 1.4V peak out. Keith
I don't know why you think your gain is 55dB in the transient analysis. You are putting 1V peak in and getting around 1.4V peak out. Keith
Nov 10, 2013 #9 A AAOAA Junior Member level 2 Joined Oct 31, 2013 Messages 20 Helped 0 Reputation 0 Reaction score 0 Trophy points 1 Activity points 150 dick_freebird said: Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop. Click to expand... Could you please tell me what do you mean precisely by this?
dick_freebird said: Begin with the validity of your AC analysis' operating point solution, i.e. whether the amplifier is linear and closed loop. Click to expand... Could you please tell me what do you mean precisely by this?