Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How to covert PWM signal to PPM signal by logic chip beyond 5MHz frequency?

Status
Not open for further replies.
M

melooop

Newbie level 4
Joined
Nov 27, 2015
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
56
How to covert PWM signal to PPM signal by logic chip beyond 5MHz frequency? MCU output PWM signal, but I need PPM signal, How to get PPM signal by logic chip?

Thanks a lot!
 

I would use a 74HC4538 monostable configured as a negative-edge triggered, non-retriggerable one shot.

You have to use the 74HC version, the normal CD version is too slow.
 

If you take the positive transition of your 5 MHZ as the clock edge, the the negative edge will occur at some time after depending on the percentage of modulation. Use the negative edge to fire a short period monostable and its output position will vary time wise with the modulation.
As the period at 5 MHZ is 20 nS, there is not much time to do any thing complicated. Depending on how wide you swing your pulse width, the error at the lowest pulse width will increase due to the firing time of the mono. I think the monostable should have a period of less then 1 nS.
Frank
 

My designing logic circuit skll is poor, may you give a circuit by 74HC version? Thanks a lot.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top