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#4600883
Dear community, I am usually more an aerodynamic expert than an electronic guy and that is why I need your help. I have a fluidic oscillator working at frequencies around 5kHz and I want to do optical measurements. Since the laser and camera system is not able to work at such high frequencies I need to do phase locked measurements. Therefore it is important to more or less hit the same phase angle of the oscillation with each measurement shot. I do have an "online" voltage signal from hot wire measurements. To generate a 0->5Volt TTL trigger signal I need a circuit arrangement with a deterministic and short time delay. The goal is to start with the phase locked measurements at one point of the oscillation (defined phase angle equal to 0°) and later on add defined time delays to achieve phase angles of 30°, 60° and so on. Where exactly I start is not important. A snapshot of the voltage signal I have at 5kHz is attached. Also there is a curcit suggestion I thought about. I also would like to have a hysteresis to have a stable circuit against noice and signal flucutations, therefore it is based on the Schmitt trigger principle. If I choose for the given circuit Vref = 5V, Vin as my voltage signal and the resistors to R1 = 5kΩ, R = 5.1kΩ and R3 = 200kΩ I should get Vin_switch1 = 2,49V and Vin_switch2 = 2,56V. The Vout as a result should switch between 0 and 5V. My first question is, am I correct with this circuit and my calculations? Second, if I am right is it better to choose smaller resitors or higher resistors (since it it only a matter of their relations) to achieve minimal delay times due to the circuit. Third, is there any other/easier/smarter way to get my "online" TTL signal? I hope I explained everything in an understandable way. If not please feel free to ask! Thousand thanks in advance! Valentin
Attached files:
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voltage_signal.jpg
(410 KB)
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circuit.jpg
(60 KB)
