2017/02/20 by Erdélyi, Tamás
#Complex Variables (math.CV) #FOS: Mathematics
paper · doi:10.48550/arxiv.1702.06198
In signal processing the Rudin-Shapiro polynomials have good autocorrelation properties and their values on the unit circle are small. Binary sequences with low autocorrelation coefficients are of interest in radar, sonar, and communication systems. In this paper we study the oscillation of the modulus of the Rudin-Shapiro polynomials on the unit circle. We also show that the Rudin-Shapiro polynomials Pk and Qk of degree n-1 with n := 2k have o(n) zeros on the unit circle. This should be compared with a result of B. Conrey, A. Granville, B. Poonen, and K. Soundararajan stating that for odd primes p the Fekete polynomials fp of degree p-1 have asymptotically κ0 p zeros on the unit circle, where 0.500813>κ0>0.500668. Our approach is based heavily on the Saffari and Montgomery conjectures proved recently by B. Rodgers. We also prove that there are absolute constants c1 > 0 and c2 > 0 such that the k-th Rudin-Shapiro polynomials Pk and Qk of degree n-1 = 2k-1 have at least c2n zeros in the annulus \z ∈ \Bbb C: 1 - (c1)/(n) lt; |z| lt; 1 + (c1)/(n) \ .