Polyphase equiangular tight frames

An equiangular tight frame (ETF) is a type of optimal packing of lines in a finitedimensional Hilbert space. ETFs arise in various applications, such as waveform design for wireless communication, compressed sensing, quantum information theory and algebraic coding theory. In a recent paper, signature matrices of ETFs were constructed from abelian distance regular covers of complete graphs. We extend this work, constructing a new infinite family of complex ETFs. Our approach involves designing matrices whose entries are polynomials over a finite abelian group, namely polyphase matrices of finite filter banks.