I am doing a Wireless ECG. I get the ECG signal and I transmit it via FM. Once I input the ecg signal to the FM transmitter input the CRO automatically displays frequencies in MHz range even without any link/connection from the circuit to the CRO. What could be wrong?

 

You've discovered radio.

Does the trace go away when you hook the ground clip to receiver circuit ground?

 

You've discovered radio.

Does the trace go away when you hook the ground clip to receiver circuit ground?

The trace goes away when I remove the ground connection from the Fm transmitter and comes only when I connect the ground clip back to the transmitter ground! I am using a Transcend MP3 player as the FM receiver.