Can radio frequency negative? If frequency is defined as an absolute number then there can be no negative frequencies, but if it is a real number negative frequencies can exist. You do need two signals

If frequency is defined as an absolute number then there can be no negative frequencies, but if it is a real number negative frequencies can exist. You do need two signals to distinguish between positive and negative frequencies, the same as you need two numbers to define a complex number.

### Can omega be negative?

Let ω be a nonnegative parameter with units of radians/second. Then the angular function (angle vs. time) −ωt + θ, has slope −ω, which is called a negative frequency. But when the function is used as the argument of a cosine operator, the result is indistinguishable from cos(ωt − θ).

Can you have a negative angular frequency?

Since rotation has two directions then the angular frequency may be positive or negative. One has a positive angular frequency and the other has a negative angular frequency. These two components when represented in the angular frequency scale they appear on the opposite side around the the zero angular frequency.

Why is FFT negative frequencies?

The ‘negative frequencies’ derive from the way the two-sided Fourier transform (as computed by fft) is characteristically depicted. The fft function returns a vector that appears to begin at the zero frequency and extends to the sampling frequency. The actual Fourier transform therefore has negative frequencies.

## What is negative frequency in FFT?

Negative frequency is the rotation vector in the opposite direction to the positive frequency. For example it is necessary to have a real (non-comlex) signal. Then we have two vectors rotating in opposite directions.

### What is the concept of negative frequencies?

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.

Can a beat frequency be negative?

The beat frequency is the absolute value of the difference between the two frequencies. A negative frequency would not make sense. Consider three frequencies.