AboutDave Nyce Expertise I have been an electronics engineer for 25 years. I can answer questions on analog and digital circuits and my specialty is sensors.
Experience I am the inventor on 23 US patents, and also some foreign ones. Developed sensors for over 25 years. Licensed private pilot (airplane and rotorcraft), have HAM radio license. I'm not an expert in computer networking.
I am a 22 boy , an assistant Engineer of Audio Engg... Would you mind answering my simple questions ?
Q : 1 dBm = ? Watt
and what is " dBm , dBu , dBV , dBr , dBg " ?
Please answer me ASAP , THANKS !!!!!!!!
Regards
Answer When the range of measurements is too wide to use a linear scale, a logarithmic scale based on the decibel can be used. The decibel is a ratio between two levels.
When the two levels are powers, the formula is:
gain or loss in dB = 10 log10 P1/P2
When the two levels are voltage or current, the formula is:
gain or loss in dB = 20 log10 V1/V2
So, if a power ratio is 3 dB, that means a power ratio of 2 times.
If a voltage ratio is 6 dB, that means a voltage ratio of 2 times.
Often, one of the values in the ratio is a standard value, the other being compared to it. For dBm, the m stands for 1 milliwatt, so the value is compared to 1 milliwatt. So, 0 dBm is 1 milliwatt.
dBu is relative to .775V, because it is the voltage developed by 1 mW when appled to 600 ohms.
dbV is relative to 1 Volt
dBr (relative) is used to specify various levels in a circuit relative to a specified zero level point.
