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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.
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Milliwatts to dbm conversion?
The 'm' in dBm means the power is referenced to 1mW. So, the power in dBm equals 10 times the log of the power in mW, or P(dBm) = 10*log(P(mW)/1mW). For example, 1W = 1000mW, so 10*log(1000/1) = 30dBm.
What is 90 dB plus 90 dB?
90 dB + 90 dB is not 180 dB. Decibels are not on linear scale, they are on a logarithmic scale, which better approximates how humans perceive loudness. You can get around the math by adding 3 decibels for every doubling of values, so 90 dB + 90 dB = 93 dB. For example: The sound pressure level of one person in conversational speech is 60dB. The maximum sound pressure level achieved in an underground railway is 100dB. If you have two people speaking, 60dB+60dB=63dB. So the achieved SpL is 63dB. It is not 120dB, which is significantly louder than an underground railway, in fact, it is about the SpL of a rock concert. The maximum theoretical value of sound is 194dB (which probably cant be achieved since it requires a sound-wave to oscillate into negative pressures (in Pascals))
What is the effective radiated power formula?
EIRP (Dbm)= Output Power(Dbm)-Losses(from cables & adapters)+Antenna Gain(Db)
Calculate the power out put of an amplifier that has an input of 15 μw and a gain of 25dB?
If you want to work in watts, convert 25dB to a scalling factor: 3dB = 2 x input 10dB = 10 x input 20dB = 100 x input ...25dB = 10 ^ (25/10) = 316.2 x input So the output is 15 micro Watts x 316.2 = (4700)/(10^6) = 4.7 milli watts If you want to work in dB, then convert 15 micro watts to dB: 10 * log |P| = dB = 10*log |15 x 10^6| = -48.2dB ***When you have very small (ie negative) dB, it is often referred to in dBm, or 1/1000 of dB ( 30 dBm = 0 dB) so the output is -18.2dBm + 25 = 6.8dBm, or -23.2dB
How 3db dandwidth equals half power bandwidth?
"3 dB" is a nickname for "1/2 power". "1/2 power" in dB = 10 log(1/2) = 10 (-0.30103) = -3.01 dB
How do you get power output with a given power input of 20dbm and three power gain which is Ap1 equals 10 ap2 equals 4 ap3 equals 23?
Two ways to do it. In this particular problem, it's a matter of opinionwhich one is easier and which one is harder.Way #1:Convert dBm to watts, multiply by gains, convert output watts to dBm.+20 dBm = 0.1 watt.Output power = (0.1 watt) x (ap1) x (ap2) x (ap3) = 0.1 x 10 x 4 x 23 = 92 watts = +49.64 dBmWay #2:Convert each gain ratio to dB, then add all dB to input power.ap1 = 10 = 10 dBap2 = 4 = 6.02 dBap3 = 23 = 13.62 dB+20 dBm + 10dB + 6.02 dB + 13.62 dB = +49.64 dBm
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
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
Milliwatts to dbm conversion?
The 'm' in dBm means the power is referenced to 1mW. So, the power in dBm equals 10 times the log of the power in mW, or P(dBm) = 10*log(P(mW)/1mW). For example, 1W = 1000mW, so 10*log(1000/1) = 30dBm.
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.
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.
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.
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
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.
What is 90 dB plus 90 dB?
90 dB + 90 dB is not 180 dB. Decibels are not on linear scale, they are on a logarithmic scale, which better approximates how humans perceive loudness. You can get around the math by adding 3 decibels for every doubling of values, so 90 dB + 90 dB = 93 dB. For example: The sound pressure level of one person in conversational speech is 60dB. The maximum sound pressure level achieved in an underground railway is 100dB. If you have two people speaking, 60dB+60dB=63dB. So the achieved SpL is 63dB. It is not 120dB, which is significantly louder than an underground railway, in fact, it is about the SpL of a rock concert. The maximum theoretical value of sound is 194dB (which probably cant be achieved since it requires a sound-wave to oscillate into negative pressures (in Pascals))
What is the effective radiated power formula?
EIRP (Dbm)= Output Power(Dbm)-Losses(from cables & adapters)+Antenna Gain(Db)
How many watts of power are represented by 0 dbm?
A decibel is a measure of relative power, to compare one power level with another. 'dBm' means dB relative to 1 milliwatt and is a common unit of power in communications systms, and 0 dBm is the same thing as 1 milliwatt.
