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The 3 dB point belongs to the cutoff frequency or the corner frequency. There the 100 % voltage is then down to 70,7 % and the power is down to 50% at the same time.
Wiki User
∙ 14y ago
Wiki User
∙ 14y ago3 dB damping in voltage (70.7 %) at the ends of a frequency band means 50 percent damping in power. That was the reason to take this 3 dB value.
Wiki User
∙ 11y ago3dB of gain rolloff is a linear reduction of gain by a factor of 2. That makes it a good reference point.
Wiki User
∙ 9y agoIt doesn't have to be, another way of defining bandwidth is at a standing-wave ratio of 2, but 3 dB is a convenient level to take if there is no pressing reason to use another value.
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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 is processing gain?
The process gain (or 'processing gain') is the ratio of the spread (or RF) bandwidth to the unspread (or baseband) bandwidth. It is usually expressed in decibels (dB).For example, if a 1 kHz signal is spread to 100 kHz, the process gain expressed as a numerical ratio would be 100,000/1,000 = 100. Or in decibels, 10log10(100) = 20 dB.
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.
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.
What is the general purpose of a bandwidth meter?
It measures the bandwidth, or amount of data, which a user has used. This is useful for companies which have limits to the amount of bandwidth they have sold, or who sell bandwidth at a price per gigabyte.
What is the relation between Noise Bandwidth and 3-dB bandwidth in ideal systems?
Bn>B3bn
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 many signal levels are required when the bandwidth is 2MHz and signal to noise ratio is 8 dB?
Use Nyquist and Shannon Heartly theorem to solve this Nyquist theorem says that Channel Capacity C = 2 * Bandwidth * log2 (Number of Signal levels) Shannon Heartly theorem says that Channel Capacity C = Bandwidth * log2( 1 + SNR) Important points to consider while solving Bandwidth is expressed in Hz SNR is expressed in dB it must be converted using dB value = 10 log10(SNR) (10 dB = 10, 20 dB = 100, 30 dB = 1000 etc..)
What is gained?
The process gain (or 'processing gain') is the ratio of the spread (or RF) bandwidth to the unspread (or baseband) bandwidth. It is usually expressed in decibels (dB).For example, if a 1 kHz signal is spread to 100 kHz, the process gain expressed as a numerical ratio would be 100,000/1,000 = 100. Or in decibels, 10log10(100) = 20 dB.
What is processing gain?
The process gain (or 'processing gain') is the ratio of the spread (or RF) bandwidth to the unspread (or baseband) bandwidth. It is usually expressed in decibels (dB).For example, if a 1 kHz signal is spread to 100 kHz, the process gain expressed as a numerical ratio would be 100,000/1,000 = 100. Or in decibels, 10log10(100) = 20 dB.
What does 925 DB on jewelry mean?
What does DB 3 925 CN mean
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.
What connectors are used for serioa ports?
a male DB-25 and a male DB-9
What is 3(20 7)?
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.
What is a mechanism that can be used on Layer 3 switches to aggregate the bandwidth of multiple uplink routed ports?
etherchannel
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.
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.
