Im trying to implement the Wigner distribution and I'm stuck on how to take the conjugate of a single point in a function. I can understand finding the conjugate of a function, and the conjugate of a complex number, but I cant understand how to take the conjugate of a single point of a purely real time series such as an ECG.
The equation I'm using is the Claasen and Mecklenbräuker auto-Wigner Distribution, and it goes like this. $\text{W}_\text{x}[n,m] = 2\Sigma_{k=\frac{N}{2}+1}^{\frac{N}{2}-1}e^{-j2km}\text{x}[n+k]\text{x}^*[n-k]$
Where $m$ is frequency, $n$ is the current discrete point, N is the number of discrete time points in $\text{x}[n]$. In this example, $\text{x}[n]$ is a biological signal such as an ECG.
Im confused on how to calculate $x^{*}[n]$. Because my ECG signal is not made up of complex numbers, it has purely real numbers.