0
dB or dBW relativ to 1W
: dBm for dB relativ to 1 milliwatt. 0 dBm= 1 mW = -30dBW
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Its interesting,but these terms are used interchangeably at times, erroneously.The term dBm is used by
communications engineers and it is absolute.Most Power meters commercially available have this scale.
It is : dBm=10log(base 10)(P1/P2) at two different Power points.Power is read always across a 50 Ohm
resistor.IEEE has made this a standard and 1mW=0dBm(-40dBm is 100nW accross 50 Ohm and +20dBm is 100mW).
As far as I know dB(not DB)refers simly to gain(and loss/attenuation as -dB).It is different this time
as the equation is not Power but a simple ratio: dB=20log(base 10)(Gain or attenuation).One can have
a reference and above that reference he is talking in positive dBs(Gain) and below in negative dBs(loss
or attenuation).Such scales can then be modified as we have done for Acoustic Emission where we talk in
dBae and our refence is the "perfect" sensor giving us ONLY 1microVolt(!) Peak output noise.Anyway a
good goal.So for 40dBae a sensor/Amplifier(40dB Gain)output across a 50 Ohm resistor is 10mV.
What else can I help you with?
How do you convert dB to DBi?
To convert dB to dBi (decibels isotropic), you need to add 2.15 dB to the dB value. This adjustment accounts for the difference in reference points used in the two scales. So, if you have a value of x dB, the equivalent value in dBi would be x + 2.15 dBi.
What is the Difference between dband dbm?
dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an abbreviation for dB with respect to 1 mW and the "m" in dBm stands for milliwatt. dBm is different from dB. dBm represents absolute power, whereas in audio engineering the decibel is usually a voltage ratio of two values and is used then to represent gain or attenuation of an audio amplifier, or an audio damping pad.
What is the difference between DB and DBMS?
dBm us almost exactly the same as dB. The only difference is that there is a reference of 1 Watt = 0 dB, and 1 mW = 0 dBm. Sorry but that is incorrect. db is a ratio and not an absolute value, by it self it means nothing. you got the dbm part right, 1 mW = 0 dbm and it is an absolute value.
How do you convert 10W to dBm?
dBm us almost exactly the same as dB. The only difference is that there is a reference of 1 Watt = 0 dB, and 1 mW = 0 dBm. dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an abbreviation for dB with respect to 1 mW and the "m" in dBm stands for milliwatt. dBm is different from dB. dBm represents absolute power, whereas in audio engineering the decibel is usually a voltage ratio of two values and is used then to represent gain or attenuation of an audio amplifier, or an audio damping pad. PdBm = 10*log10(1000*10W) = 40dBm
What is the difference between Dbi and Dbm?
There are a few terms that need to be understood. [dBm,dBd,dBi and dB] For antennas, a common reference unit is the dBi, which states the gain of an antenna as referenced to an ISOTROPIC source. An Isotropic source is the perfect omnidirectional radiator, a true "Point Source", and does not exist in nature. Consider it a source which is the center of the sphere and the energy is coming equally out of it as a sphere. Now in reality nothing like that exists. It's also 2.41 dB BIGGER than the next common unit of antenna gain, the dBd, When you convert that to a real antenna. So a simple dipole antenna has a gain of 2.41dBi, and a gain of 0dBd, since we're comparing it to itself. Now lets talk about dBm, dBm is not is reference to anything else but the used as an actual gain ( say amplifiers ) , P(dBm)=10*LOG(1000*Power in milliwatts,10), an amp with an output of 30dBm puts out 1 Watt. It is not in refernce to two power level but directly correlating the gain of a device. Now when you talk about a dB it is a relative measure of two different power levels. 10log (p1/p2, 10).
What is fading margin?
Thermal fade margin TFM in db is the difference between the normal received signal RSL at the input of microwave receiver expressed in dbm and the receiver's threshold ( given by the manufacturer) expressed in dbm TFM = RSL - TH
What is thermal fade margin?
Thermal fade margin TFM in db is the difference between the normal received signal RSL at the input of microwave receiver expressed in dbm and the receiver's threshold ( given by the manufacturer) expressed in dbm TFM = RSL - TH
How do you convert dBm to dB?
the first convert the power in dBm to MW, the define of dBm=10 log (P MW) -10 log ( 1mw). example: let P=-2 dBm convert this to dB? answer: Pmw= inv log(-2/10)=0.630mw*1000 micw/mw=630 microw 10log(630)=28dB
How do you convert the 1db to dbm?
dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an abbreviation for dB with respect to 1 mW and the "m" in dBm stands for milliwatt. dBm is different from dB. dBm represents absolute power, whereas in audio engineering the decibel is usually a voltage ratio of two values and is used then to represent gain or attenuation of an audio amplifier, or an audio damping pad.
How do you convert dBm to watts?
dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an abbreviation for dB with respect to 1 mW and the "m" in dBm stands for milliwatt. dBm is different from dB. dBm represents absolute power, whereas in audio engineering the decibel is usually a voltage ratio of two values and is used then to represent gain or attenuation of an audio amplifier, or an audio damping pad.
Convert db to dbm?
Here's how to convert dB units (with usually a 1 Watt or whatever 1 value as reference) to dBm units (with a 1 miliWatt reference value):x= value to be convertedx [dB]= x + 30 [dBm]Proof:P= 1 Watt--> 10*log10(1)= 0 [dB] (this is 1 Watt in dB)--> 10*log10(1/(1*10^(-3)))= 10*log(1*10^3)= 30 dBm (this is 1 Watt to dBm)Now, if you do whatever number of examples you want to do, you'll end up in concluding the conversion dB to dBm is totally linear without of actually having to proof the linear properties. (i'm too lazy to write it here).Hope this helps....Regards,STMI
Prove dbm plus dbm equals db?
The decibel scale is a logarithmic scale where each change in three dB represents a power factor change of two. (3 dB is power times two, 6 dB is power times four, 9 dB is power times 8, etc. Similarly, -3dB is power divided by two, -6 dB is power divided by four, etc.) Zero dB is assigned some arbitrary reference power. One example is 1 mV across 600 ohms. If you double the voltage into a constant resistance, the power quadruples, so 2 mV would be +6 dB, 4 mV would be +12 dB, etc. The letter after dB is the reference power. In the case of dBm, it means that 0 dB is 1 milliwatt, so 2 milliwatt is +3 dB, etc. There are many dB scales, such as dBa, used in sound measurements. Still, fundamentally, 3 dB is a doubling of power, -3 dB is a halving of power, so, for any arbitrary scale, say dBq, then saying +6dBq is saying a power four times higher than 0 dBq. In the end, dBm plus dBm is delta dB, with no scale.
