How to recover data which is coded using machester line coding?

[iVenky]

I want to recover data from the machester line coded format.

One way is to recover the clock. But how do you recover the clock?
There are few conditions though. I can't have a reference clock in my circuit. This means that I have to extract the clock always as the data comes in. This clearly eliminates PLL so don't tell me about recovering the clock through PLL. Do you know any method to recover the clock?

Is it possible to recover the data without using the clock may be using some kind of asynchronous sequential circuit?

Thanks in advance.:grin::grin:

 

[godfreyl]

According to Wikipedia it's self-clocking, so there should be no problem. There's some info here to start with:
https://en.wikipedia.org/wiki/Manchester_code
https://en.wikipedia.org/wiki/Clock_recovery
https://en.wikipedia.org/wiki/Self-clocking_signal

 

[iVenky]

I know that it is self clocking. But the problem is to recover the clock from the signal. As I had told you before I can't have a separate local oscillator in the receiver which means that you can rule PLL. That "clock recovery" link in wiki uses PLL. I need to get the clock from the data without using any reference clock.

 

[godfreyl]

IMHO, with no oscillator and no clock, you're going to have a tough time. Surely you need some sort of timing information to tell the difference between a long pulse and a short pulse? I suppose you could do it with an integrator.

 

[yuvko]

here is one way to do it (with known clock rate):
1) wait for a change on your rx line.
2) from the change 3/4 of the clock rate cycle.
3) get the Rx line level as data (1 or 0).
go back to step 1

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[ZacharyRoth]

Yes, there are some data recovery software available to recover your data!