Enter Company. Enter Email. Enter Password. Create Account. Already have an account? Sign In. Login Login to everything RF to download datasheets, white papers and more content. Forgot Password?
Don't have an account? Sign Up. Full Name:. Your company name:. Getting Media Kit. Cancel Download. Image Link. Cancel Save. Note: File Size should be less than 10MB. Therefore a small increase in decibels represents a large increase in intensity. For example — 10dB is 10 times more intense than 1dB, while 20dB is times more intense than 1dB. The decibel dB is a logarithmic unit used to measure sound level. It is also widely used in electronics, signals and communication. The dB is a logarithmic way of describing a ratio.
The ratio may be power, sound pressure, voltage or intensity or several other things. How many times more intense is a 60 dB sound than a 30 db?
In intensities, it is times louder. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Physics What is 3db frequency? Ben Davis March 23, What is 3db frequency? What are the types of active filters? It is just saying the filter cuts off half of the power at that frequency. The rate at which it drops off depends on the order of the system you are using.
Higher order can get closer and closer to a "brick wall" filter. Well, many reasons. All devices analog or digital have to do something with the signal. You can go as simple as a voltage follower up to something more complex like showing the signal on a screen or turning the signal into audio.
All of the devices required to convert your signal into something that is usable have attributes about them that are frequency dependent. It is just saying the filter cuts off half of the power at that frequency.
The rate at which it drops off depends on the order of the system you are using. Higher order can get closer and closer to a "brick wall" filter. Well, many reasons. All devices analog or digital have to do something with the signal. You can go as simple as a voltage follower up to something more complex like showing the signal on a screen or turning the signal into audio. All of the devices required to convert your signal into something that is usable have attributes about them that are frequency dependent.
One simple example of this is an opamp and its GBWP. So, on an O-scope they will add a low pass filter so that none of the internal devices are having to deal with frequencies above what they can handle. When an oscope says its -3dB point is MHz they are saying they have placed a low pass filter on its input has a cut off frequency -3dB point of MHz. The modulus graphic on the bode diagram of a first order high pass or low pass filter, can be approximated by two lines.
The point which the two lines meet, when compared to the real line gives us the number of -3db. This point is called the cutoff frequency. So, lots of systems are designed to operate in normal conditions until they met the cutoff frequency when they lose at maximum 3db.
If you operate with signal above that frequency the signal can be more attenuated. More info in Wikipedia about continuous low pass filters. The -3dB, come from 20 Log 0. Kellenjb's answer is excellent, I just wanted to add a webpage that gave me a "Ohhh" moment when I was reading about this -3db thing.
Maybe it helps to visualize. I read a tutorial on Band Pass filters which includes a great image of a Bode Plot. You can see the key image below.
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