If the autocorrelation function of the sinusoidal signal x(t) = A cos (ω0 t + ϕ) is R(τ), then R(0) is given by (in terms of power spectral density of R(τ) = S(f))

• A. \(R\left( 0 \right) = \mathop \smallint \limits_{ - \infty }^\infty S\left( f \right)df\)
• B. \(R\left( 0 \right) = \mathop \smallint \limits_{ - \infty }^\infty \exp \left\{ {S\left( f \right)} \right\}df\)
• C. R(0) = S(f)|f = ∞
• D. \(R\left( 0 \right) = \mathop \smallint \limits_{ - \infty }^\infty lnS\left( f \right)df\)