Properties:

• Convolution of two half-length rectangular windows
• Main lobe twice as wide as that of a rectangular window of length $M$ (i.e., not that of the half-length rectangular window which generates the triangular window via self-convolution).
• First side lobe twice as far down as rectangular case (-26 dB)
• Often applied implicitly to sample correlations of finite data
• Also called the ``tent function''
• $M-1$ often replaced by $M$ or $M+1$ to avoid including endpoint zeros