any one could you explain about dbMicro to dbm convertion.
dBm is dB above 1mW into a 50 Ohm load. by ""dbMicro" I believe you mean dBuV, or dB above a microvolt.
This website calculator also explains a little bit about how to convert between the two. Just remember that the dBm number assumes a 50 Ohm load resistance. Otherwise it would make no sense to talk about a conversion between a voltage and a power.