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Problem with sending dtmf over pmr radio

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bilgekaan

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Hello,
I am trying to send dtmf signal over pmr radio. I am missing some dtmf codes in the receiver side.I checked the signals in the receiver side with a scope. I saw that signal is corrupt ( corruption is observed at the end of signal ). I attached scope snapshot. Blue is correct signal, orange is received.When
I changed the radio on the tx side, corruption level is changed(with different brand of pmr radio).
I am waiting for your suggestions and solution ideas.
regards
 

deepuj

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Re: dtmf over pmr radio

Looks like it might just be a simple phase shift... Is should not affect decoding (or I am missing something)! Try increasing the pulse length so that the decoder can decode it better...

Just a silly check.. you are ac coupling the signal input to the decoder using a blocking capacitor right?
 

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