PWM to TTL...

[Morkai]

Hi everyone. I'm having some trouble figuring something out...

I want to take an incoming PWM signal, and convert it back to TTL...

I'm making a wireless infrared transmitter/receiver, that converts a TTL signal into a PWM signal, and then transmits it, and recovers the original TTL signal from the PWM signal. I'm transmitting at 9600 baud (4.8Khz)

I"m having problems figuring out how to do this. From what I know, best way to do it, is to convert the signal into a PAM signal, and then put it through an integrator and low pass filter to recover it.

If anyone has any ideas on how to do this, or any links/info, that would be great.

 

[Nigel Goodwin]

You don't give any indication of what the signal's like?, are you using specific pulse widths for a zero and a one?. If so you should also use an extra pulse width for a start bit, in order to identify the start of a byte.

You need to be aware that the received pulse aren't the same width as the transmitted ones, and also check that the system will cope with the speeds you're attempting!.

You might check my IR PIC tutorial which uses the Sony SIRCS system, this uses a PWM scheme.

Basically you need a micro-controller solution, hardware would be far more complicated.