40 dB has ten times the power of 30 dB. 50 dB has another ten times as much power.
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.
The power in the wave is [ 30 dB = 1,000 times ] greater.
(90 dB - 70 dB) = 20 dB = 100 times as much sound power.(100 times 'as much' = 99 times 'more')
Given P = 100 watts. Reference sound intensity Po = 10^−12 W. Reference sound intensity level LPo = 0 dB. Get power level LP in dB when entering sound power P in watts. Power level LP = 10×log (P / Po) dB = 10×log (100 / 10^−12) = 140 decibels (dB).
dB (decibel) is a logarithmic measure of the ratio of two power values, for example, two signal strengths. This is often used for power gain or power loss. For example, a loss of 10 dB means that the signal degrades by a factor of 10, a loss of 20 dB means that the signal degrades by a factor of 100, and a loss of 30 dB means that the signal degrades by a factor of 1000.
When the power (energy) is dropped to the value of 50 percent, the decibel loss is 3 dB, but the voltage is dropped to the value of 70.1 percent. Power drop to 50 % means -3 dB; that is 70.1 % voltage drop. Power drop to 25 % means -6 dB; that is 50 % voltage drop.
an output power which is one - quarter of the input power
yes
Gain in decibels is a logarithmic base 2 scale with a multiplier of 3, so 3 db is twice the power, 6 db is four times, etc. Gain of -3.5 db means a power loss of 21.17, or a ratio of about -2.25. Note, however, that this is power, not voltage. Since power is voltage times amperes, and since amperes is voltage divided by resistance, in order to achieve a power loss of 2.25, the voltage must change by the square root of that, so the voltage changed by -1.5.
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.
40 dB has ten times the power of 30 dB. 50 dB has another ten times as much power.
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.
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.
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.
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.
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.