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Author Topic: Electronics design.  (Read 6720 times)

Offline Jokker

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Electronics design.
« on: September 12, 2009, 11:03:37 PM »

Im offering a electronics design service.
The device, I like to design, is a PWM with frequency modulation, because i think this is what you guys are looking for.

The specs could be:
- Character LCD displaying:
- Hz to Mhz frequency
- Duty cycle

Custom feature  could be linkage to a sensor output, but it is too complicated and not well controllable ..

If interested contact by replying here. Many thanks.

« Last Edit: February 29, 2016, 07:16:49 AM by hartiberlin »

Offline Jokker

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  • Posts: 84
Re: Electronics design.
« Reply #1 on: December 17, 2009, 07:40:41 PM »

First of all. How fast and in what amounts you want this devise to be delivered ?

At the moment iv got a ongoing project for a firm which need to be finished completely little before next winter and school is on.

Next, i like you to understand that very much could be done, but it requires resources. By resources i mean most of all big amount of work time and experience. The cost of product is not too much. Component value min is 10 $ and reasonable features with some performance 50 $  for signal part.

Experience = less time.

As i previously told im working on a project = experience.
Iv already done (much time to program) 
Very flexible LCD menu system , hardware real time clock calender, PID (parameter control) algorithm (good performance ... integer math )

What can be done.

Small amount of time:
- PWM with ~0.01 % duty cycle accuracy. Period is mostly constant (not much external circuity req.) (so not much frequency variation)

Medium amount of time:
- 2 PWM combined. low accuracy loss and variable frequency. (med amount of external circuitry required for MCU)

More amount of time:

- Same method (2 or more PWM)  to achieve waveforms  (anything you name or draw) Sampling and more complex algorithms are needed.  I cant tell you how high the frequency could be . Atm. i can tell (more sampling (good quality, resolution) = less max frequency.
-The very complex task could be to use more and more external circuitry (to combine) to  achieve what you need. Good part is i believe very high frequencies . Less good part is not ultimate variation in form.

Min and max  square wave (easiest) ?
 0 hz to Ghz (basically semiconductor performance ) - med amount of time.

To create a waveform with sharp edges variable rise time is needed... it might mean sampling but maybe it could be achieved with external circuitry so not much losses.

To create sine sampling is needed cant tell max freq atm accurately.. probably max i can say (ghz. is not too complicated. )

Q*What is the shortest reasonable pulse capability, 100 nanoseconds? less? same off length 16-17 milliseconds.

Probably little less that 10 ns wide pulse repeated in amount time, time you say. Again it is accuracy. Easy is 16 bit but iv seen (external) 24 bit PWMs  (tip* 4 bit max is 16 and 5 bit max is 32 ...) so you can get the picture about accuracy. and accuracy is 1/x bits.

Q*What voltages ?
It is related to switching element and capacitor element.  Btw ... i believe this part you may want to be controlled also. And voltage control is expensive because of transformer. Also could be achieved by capacitors and voltage progressive doublers but it is big energy loss and low variation also it is process, little like sampling.
So answer is better transformer = higher energy efficient voltage and switching element rise time (situation between ON OFF) is in nS

« Last Edit: December 17, 2009, 08:07:18 PM by Jokker »

Offline forest

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Re: Electronics design.
« Reply #2 on: February 28, 2016, 10:17:12 AM »
There is also second need, maybe less popular,however would be nice to have dyi sinewave generator with variable frequency and low distortion. The best one could have two channels of sinewaves with phase difference regulated (like 90,180 phase shift).
If you are experienced electronic designer then maybe you can also help with combining such sinewave generator with microcontroller so uc could adjust precisely sinewave output frequency by PWM output for example.
What do you think ? Any advice is appreciated.