0
dB expresses the ratio of two powers.
Negative dB doesn't mean negative power.
It means a negative ratio . . . less power compared to more power,
or the power decreased.
Wiki User
∙ 10y ago
Add your answer:
Earn +20 pts
What is db levels?
The decibel (db) is a logarithmic unit that indicates the ratio of a physical quantity (usually power or intensity) relative to a specified or implied reference level
How will an increase in amplitude and power affect dB?
The decibel (dB) scale is logarithmic. An increase of power by a factor of 10 is an increase of +10 dB. If power increases by a factor of 100, that is equivalent to +20 dB.The decibel (dB) scale is logarithmic. An increase of power by a factor of 10 is an increase of +10 dB. If power increases by a factor of 100, that is equivalent to +20 dB.The decibel (dB) scale is logarithmic. An increase of power by a factor of 10 is an increase of +10 dB. If power increases by a factor of 100, that is equivalent to +20 dB.The decibel (dB) scale is logarithmic. An increase of power by a factor of 10 is an increase of +10 dB. If power increases by a factor of 100, that is equivalent to +20 dB.
What db has no sound?
dB is a logarithmic scale, so the answer, basically, is negative infinity.dB is a logarithmic scale, so the answer, basically, is negative infinity.dB is a logarithmic scale, so the answer, basically, is negative infinity.dB is a logarithmic scale, so the answer, basically, is negative infinity.
What is the implication of negative voltage gain?
If the input and output are expressed in volts, then negative gain means a 180° phase shift. If the ratio of output to input is expressed in dB, then negative gain means attenuation, i.e., less power out than power in.
Is there more energy in a 30 dB or 40dB sound wave?
40 dB has ten times the power of 30 dB. 50 dB has another ten times as much power.
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.
How many milliwatts in 36 dB?
I guess the reference power for 0 dB is 1 milliwatt. Then the power level 36 dB means a power ratio of 10^(36/10) = 3981 to 1.
What do means by 3 dB?
3 dB is a change in power by a factor of 2. If it is plus, i.e. +3dB, power is doubled. If it is minus, i.e. -3dB, power is halved. 6 dB, then is a factor of four, or quarter; 6 dB is a factor of eight, or eighth, etc. The actual equation is 3 log2 (POWER OUT / POWER IN).
If transmitter power is increased from 200 Watts to 400 Watts how do you convert to Db form?
Decibels (db) is relative power, log base 2, times 3. Increasing power from 200 watts to 400 watts is doubling power, so the decibel change is +3 db.800 watts would be +6 db, 1600 watts would be +9 db, 100 watts would be -3 db, 50 watts would be -6 db, and so on.
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
What does one calculate dB power?
This calculation will give you the ratio, in decibels, between two power values. For example, you can calculate the difference in dB between two amplifiers with different power output specifications calculate in dB Power Ratio.
What is 3 dB?
3 dB is a way to describe the amount by which power increases when it doubles.1 dB = increase 26%2 dB = increase 58%3 dB = double4 dB = 2.51 times5 dB = 3.16 times6 dB = 4 times (3 dB + 3 dB = double double)7 dB = 5 times8 dB = 6.31 times9 dB = 8 times (3+3+3 = double double double)10 dB = 10 timesSimilarly-1 dB = decrease 26%-2 dB = decrease 58%-3 dB = halve-4 dB = decrease 2.51 times...etc...The equation is:dB change = 3 log2 ( final power / initial power )Edit:The more "official" equation used to compute a decibel Gain/Loss when comparing power values is this:GdB = 10*log10(Pout/Pin)Where GdB is the gain in power (if the value is negative, it means loss)and Pout is the power level seen at the outputand Pin is the power level seen at the inputAlso, 0 dB means no change in power.Note: If you're measuring an amplitude (like a Voltage or Current value), then the decibel equation increases by a factor of 2:GdB = 20*log10(Pout/Pin)So, to double an amplitude, a 6dB increase would be required.In other words, take the values at the top of this answer, and double the left side of the equation, and that's how it works with amplitudes.Lastly, it's important to understand that when multiplying in the linear world, you are adding in the decibel world. If you double a power level 2 times (e.g. 10 watts -> 20 watts -> 40 watts), you are multiplying 4 fold, but you are increasing by 6 dB (3dB + 3dB = 6dB).BUT if your talking about audio (sound) 1db is the smallest change in sound volume the human ear can detect.
