Howtosignalprocessing
Negative frequency is an idea associated with complex exponentials. A single sine wave can be broken down into two complex exponentials ('spinning numbers'), one with a positive exponent and one with a negative exponent. That one with the negative exponent is where you get the concept of a negative frequency.
- Why there is no negative frequency?
- Can you have a negative beat frequency?
- Can the frequency of light be negative?
- Can wavelength be negative in physics?
Why there is no negative frequency?
In the "real" world, you don't need negative frequencies (because, as mentioned before, a real signal always consists of equal parts at positive and negative frequencies, for example, the sine is a difference of two exponentials with a positive and a negative frequency with the same absolute value).
Can you have a negative beat frequency?
The beat frequency is the absolute value of the difference between the two frequencies. A negative frequency would not make sense.
Can the frequency of light be negative?
When describing the propagation of light, the equations require that we describe the light field as having both positive and negative frequencies. A negative frequency would indicate a wave made up of photons that have a negative energy, something that doesn't necessarily make a lot of sense.
Can wavelength be negative in physics?
For example, if nI is smaller than nF, then the wavelength will be positive which corresponds to absorption. If nF is smaller than nI, then the wavelength will be negative which corresponds to an emission.
