| ??? 07/13/05 23:29 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#97279 - Schematic Responding to: ???'s previous message |
Hallo Pradono,
sorry for being late, but was busy... This is your circuit as gif-file:  In this circuit there are several mistakes! 1. First LM318 does not work as active bandpass, as I suggested in an earlier post! Left terminal of C2 must be connected to the point, where R1 and C1 join each other. 2. Input impedance of bandpass is too low to provide adequate loading for the ultrasonic sensor. You shouldn't connect the sensor directly to this bandpass, but to a buffer stage. 3. As you use bipolar supply voltage for the LM318s, there's no need to bias the non-inverting input of U1 by half of positive supply voltage. You can connect this pin directly to signal ground. 4. The gain is much too high! As the first bandpass (if connected properly) provides a gain of 50 at 40kHz, you don't need further gain of 100 x 60 = 6,000. Your total gain then is 50 x 6,000 = 300,000 which is absolute total overkill! Such a circuit cannot work properly at all... 5. R10 must be located behind C9, not in front of. I would recommend you the following circuit:  Take care, the 180pF capacitors must be polystyrene, polypropylen or NP0!!! No other type!!! And they must show very little tolerance, less than +-1%!!! Power supply decoupling isn't shown in the schematic but nevertheless urgently needed. Use the one you draw in your schematic. Capacitor at 10kOhm poti can be in the range of 10...100n. Use only good capacitors for the 10n caps. Mica (polyester) or X7R is adequate. Kai |
| Topic | Author | Date |
| Ultrasonic Signal Processing | 01/01/70 00:00 | |
| Time dependant gain | 01/01/70 00:00 | |
| Further attenuation... | 01/01/70 00:00 | |
| Signal recovery. | 01/01/70 00:00 | |
| AGC? | 01/01/70 00:00 | |
| AGC as Steve said// | 01/01/70 00:00 | |
| My Algorithm was: | 01/01/70 00:00 | |
| My Algorithm was: | 01/01/70 00:00 | |
| Ultrasonic Ranging | 01/01/70 00:00 | |
| Matched filter on the rescue | 01/01/70 00:00 | |
| matched filters | 01/01/70 00:00 | |
| Phase locked amplifier | 01/01/70 00:00 | |
| Its a different thing | 01/01/70 00:00 | |
| Ah | 01/01/70 00:00 | |
| Thats the one.... | 01/01/70 00:00 | |
| Clever woman | 01/01/70 00:00 | |
| Just an idea | 01/01/70 00:00 | |
| The scope plot tells it all! | 01/01/70 00:00 | |
| Largest signal | 01/01/70 00:00 | |
| 'Greatest' echo is the wrong criterion! | 01/01/70 00:00 | |
| | 01/01/70 00:00 | |
| somehow I remember... | 01/01/70 00:00 | |
| No, no... | 01/01/70 00:00 | |
| Oops~ forgot... | 01/01/70 00:00 | |
| the product | 01/01/70 00:00 | |
| Power of transmission pulse | 01/01/70 00:00 | |
| Preamp circuit Here | 01/01/70 00:00 | |
| Add caps to remove base line noise | 01/01/70 00:00 | |
| Another potential problem... | 01/01/70 00:00 | |
| Problem with ADC? | 01/01/70 00:00 | |
| possible solution to the ADC problem | 01/01/70 00:00 | |
| Ok~ | 01/01/70 00:00 | |
| Debug Result | 01/01/70 00:00 | |
| ADC Sampling and code debugging | 01/01/70 00:00 | |
| sampling time | 01/01/70 00:00 | |
| Adc for Ultrasonic? | 01/01/70 00:00 | |
| Next, comes to "average" | 01/01/70 00:00 | |
| Why use the adc? | 01/01/70 00:00 | |
| Forgot to tell... | 01/01/70 00:00 | |
| Circle in RED | 01/01/70 00:00 | |
| Asking for help again - Filter | 01/01/70 00:00 | |
| Notch | 01/01/70 00:00 | |
| I don't know | 01/01/70 00:00 | |
| DSP | 01/01/70 00:00 | |
| Nah | 01/01/70 00:00 | |
| for the sake of learning | 01/01/70 00:00 | |
| so | 01/01/70 00:00 | |
| I agree | 01/01/70 00:00 | |
| Amplitude | 01/01/70 00:00 | |
| Op amps | 01/01/70 00:00 | |
| 100pF | 01/01/70 00:00 | |
| bypass ?? | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| No sort of bypass | 01/01/70 00:00 | |
| BTE054 BTE054USS2 | 01/01/70 00:00 | |
| Better noise control | 01/01/70 00:00 | |
| re: BTE054 | 01/01/70 00:00 | |
| Replace LMV6032 with LM324 | 01/01/70 00:00 | |
| re:low sensitivity | 01/01/70 00:00 | |
| re:no filtering | 01/01/70 00:00 | |
| Note | 01/01/70 00:00 | |
| Notch filter? | 01/01/70 00:00 | |
| No, | 01/01/70 00:00 | |
| Bandpass | 01/01/70 00:00 | |
| NOT a criticism | 01/01/70 00:00 | |
| Update... | 01/01/70 00:00 | |
| Umm... Nowadays? | 01/01/70 00:00 | |
| Op amp parameters | 01/01/70 00:00 | |
| "Filters for Dummy" | 01/01/70 00:00 | |
| Have you tried it with ..... | 01/01/70 00:00 | |
| Yes, I've tried it and it works well | 01/01/70 00:00 | |
| Basic electronics | 01/01/70 00:00 | |
| 0.002uF -> 3300uF | 01/01/70 00:00 | |
| re:noise | 01/01/70 00:00 | |
| Exactly the same | 01/01/70 00:00 | |
| test of signal | 01/01/70 00:00 | |
| It's over 1.2m | 01/01/70 00:00 | |
| TWO bypass caps. | 01/01/70 00:00 | |
| Two were found | 01/01/70 00:00 | |
| Usenet | 01/01/70 00:00 | |
| Why using a PLL, when a bandpass can ... | 01/01/70 00:00 | |
| which is why ,,,, | 01/01/70 00:00 | |
| Not sure what you meant.. | 01/01/70 00:00 | |
| Already | 01/01/70 00:00 | |
| But it MUST work properly!! | 01/01/70 00:00 | |
| Circuit here | 01/01/70 00:00 | |
| Op-amp to replace LM324 | 01/01/70 00:00 | |
| Non-inverting Input Voltage Divider | 01/01/70 00:00 | |
| LM567 | 01/01/70 00:00 | |
| re:LM324 | 01/01/70 00:00 | |
| re:wrong link | 01/01/70 00:00 | |
| No AGC | 01/01/70 00:00 | |
| AGC | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| re: no AGC | 01/01/70 00:00 | |
| LMC6032 is much more linear than LM324 | 01/01/70 00:00 | |
| re: | 01/01/70 00:00 | |
| re:attenuation of signal | 01/01/70 00:00 | |
| Good ones and bad ones | 01/01/70 00:00 | |
| another article of interest | 01/01/70 00:00 | |
| tramsmit & receive | 01/01/70 00:00 | |
| how to measure the distance perfectly? | 01/01/70 00:00 | |
| Fatal Error! | 01/01/70 00:00 | |
| How about this one.... | 01/01/70 00:00 | |
| Ultrasonic Detection Code! | 01/01/70 00:00 | |
| is that right? | 01/01/70 00:00 | |
| Not right,,,,, | 01/01/70 00:00 | |
| Thanks! | 01/01/70 00:00 | |
| another missing! | 01/01/70 00:00 | |
| i'll try it.. | 01/01/70 00:00 | |
| Some Applications of ultrasonic | 01/01/70 00:00 | |
| "Op amps for everyone" | 01/01/70 00:00 | |
| woo... tiring trip | 01/01/70 00:00 | |
| Check this one | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| is it not fundamentally wrong | 01/01/70 00:00 | |
| Both | 01/01/70 00:00 | |
| I knew that... | 01/01/70 00:00 | |
| Synthetic grounds | 01/01/70 00:00 | |
| no, Kai | 01/01/70 00:00 | |
| Steve, Erik | 01/01/70 00:00 | |
| The circuit works, but... | 01/01/70 00:00 | |
| Moral | 01/01/70 00:00 | |
| Puh, what antennas... | 01/01/70 00:00 | |
| Which means I can't use breadboard | 01/01/70 00:00 | |
| In one word. | 01/01/70 00:00 | |
| Using the LM318 | 01/01/70 00:00 | |
| Missing 10K | 01/01/70 00:00 | |
| More caps | 01/01/70 00:00 | |
| Where? | 01/01/70 00:00 | |
| Parallel | 01/01/70 00:00 | |
| Does it work now? | 01/01/70 00:00 | |
| Yes, it works fine | 01/01/70 00:00 | |
| Theoretical work missed | 01/01/70 00:00 | |
| Fatal Error! | 01/01/70 00:00 | |
| Another article to peruse | 01/01/70 00:00 | |
| Another one... | 01/01/70 00:00 | |
| same application | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| Why sorry? | 01/01/70 00:00 | |
| That's exactly what I want to do | 01/01/70 00:00 | |
| which one is the best way? | 01/01/70 00:00 | |
| Capacitors | 01/01/70 00:00 | |
| i've got it | 01/01/70 00:00 | |
| not the best solution | 01/01/70 00:00 | |
| Laser ranging | 01/01/70 00:00 | |
| how much | 01/01/70 00:00 | |
| I've withdrawn from the competition | 01/01/70 00:00 | |
| NOT finance | 01/01/70 00:00 | |
| Re: money is not everything | 01/01/70 00:00 | |
| Good Luck | 01/01/70 00:00 | |
| good luck | 01/01/70 00:00 | |
| Good luck | 01/01/70 00:00 | |
| Thanks! | 01/01/70 00:00 | |
| The noise again | 01/01/70 00:00 | |
| re:link | 01/01/70 00:00 | |
| Link | 01/01/70 00:00 | |
| this is the link | 01/01/70 00:00 | |
| re:noise | 01/01/70 00:00 | |
| 5-14 Khz | 01/01/70 00:00 | |
| re:5-14kHz | 01/01/70 00:00 | |
| The Noise Amplitude | 01/01/70 00:00 | |
| gain | 01/01/70 00:00 | |
| the problem is gain | 01/01/70 00:00 | |
| Schematic | 01/01/70 00:00 | |
| Thank You but... | 01/01/70 00:00 | |
| Thank You but... | 01/01/70 00:00 | |
| 1/4Watt is enough | 01/01/70 00:00 | |
| Simulation result | 01/01/70 00:00 | |
| Strange plots... | 01/01/70 00:00 | |
| How about Compensation? | 01/01/70 00:00 | |
| Not needed | 01/01/70 00:00 | |
| Bigger Pulse | 01/01/70 00:00 | |
| Bridge configuration can help | 01/01/70 00:00 | |
| The same circuit but... | 01/01/70 00:00 | |
| ...but much stronger | 01/01/70 00:00 | |
| I have tried | 01/01/70 00:00 | |
| What do you mean by ripple? | 01/01/70 00:00 | |
| The ripple | 01/01/70 00:00 | |
| No, it is not. The output from a logic | 01/01/70 00:00 | |
| Answer | 01/01/70 00:00 | |
| Yup Kai | 01/01/70 00:00 | |
| It's to adjust oscillating frequency | 01/01/70 00:00 | |
Finished | 01/01/70 00:00 | |
| Exams VS academic | 01/01/70 00:00 | |
| "Plan B" | 01/01/70 00:00 | |
| Universities in HongKong | 01/01/70 00:00 |