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I want good noise immunity for an IC project I'm working on for my XJ and I'm planning on using TTL, which has .4V built in hysteresis. My question is, is that suffecient noise immunity or should I incorporate a one-shot and some Schmitt triggers to run the inputs on my IC's?
I'm very new to the electrical engineering thing so help me out :greensmok
If you bias the transistors correctly such that given the noise that your jeep sees (I think factory spec was a .1 to .5v AC signal is what every thing else on board would have to deal with). so a built in .4v noise variation should work assuming you have good grounds and you have not done any thing else to change the AC signals that are generated through the system.
with not knowing what TTL IC your trying to make I am not sure if you are using the term hysteresis correctly. That is the accuracy for an object (usualy in analog) to return back to its starting position when comming from the right compared to as if it was comming to the left.
i.e. A stepper motor with a linear position sensor. the motor is told to advance 5" and then return back to home. the sensor will read a slightly different reading then before it started (due to variations in the sensor and in the stepper motor). then the motor is told to go -5" and then back to home. the difference between the two is hysteresis.
Edit: Also to get rid of noise a combination of capacitors can get rid of most the noise since the block AC signals. but will effect the frequency response and gain of the circuit depending on how they are used and where they are located.
By hysteresis I'm mainly wondering if I should incorperate Schmitt triggers and/or a monostable multivibrator or if that's overkill. The project is a fairly simple preloadable U/D counter with a few features based on a 74LS169. Sorry for the amateur info, like I said, I'm still trying to get used to the electrical engineering thing.
by any chance are you going to school to be an electrical engineer? my guess is that what ever you are trying to do is being waaaayyy over engineered. don't get me wrong, its cool if you can figure this stuff out but from my experience there is the engineering world, and then there is the real world. I do I&C work for a boiler company and I have seen a ton of control systems that an engineer has designed which was plc based which could have been done with a few time delay relays...when I'm out in the sticks, my motto is K.I.S.S.
If you bias the transistors correctly such that given the noise that your jeep sees (I think factory spec was a .1 to .5v AC signal is what every thing else on board would have to deal with). so a built in .4v noise variation should work assuming you have good grounds and you have not done any thing else to change the AC signals that are generated through the system.
with not knowing what TTL IC your trying to make I am not sure if you are using the term hysteresis correctly. That is the accuracy for an object (usualy in analog) to return back to its starting position when comming from the right compared to as if it was comming to the left.
i.e. A stepper motor with a linear position sensor. the motor is told to advance 5" and then return back to home. the sensor will read a slightly different reading then before it started (due to variations in the sensor and in the stepper motor). then the motor is told to go -5" and then back to home. the difference between the two is hysteresis.
Edit: Also to get rid of noise a combination of capacitors can get rid of most the noise since the block AC signals. but will effect the frequency response and gain of the circuit depending on how they are used and where they are located.
yes Usually is also spelled wrong. Go to the off topic area if your prowling for a high post count.
I am sorry if two words with an extra "m" in there is cause for you to post Off-topic. I would hate to see what you do to any one who has 3 or more miss-spelled words or the people that suck at life and type the way they speak.
