Howtosignalprocessing
- What does it mean when frequency is negative?
- What is fractional frequency?
- Why does FFT have negative frequencies?
- Can FFT be negative?
What does it mean when frequency is negative?
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.
What is fractional frequency?
Fractional frequency reuse (FFR) is an interference management technique well-suited to OFDMA- based cellular networks wherein the cells are partitioned into spatial regions with different frequency reuse factors.
Why does FFT have negative frequencies?
The reason is that the Fourier transform is symmetric about the y-axis, because the Fourier transform is mathematically defined on the interval (-Inf,Inf). The actual Fourier transform therefore has negative frequencies.
Can FFT be negative?
FFT gave a result in complex coordinates. Absolute value of all data points should be taken . Power values are absolute values of complex numbers derived from FFT. They can not be negative unless they are contrasted to baseline or other conditions.
