A time-domain method for pseudo-spectral characterization

We present a generic method for determining transfer function of a DUT using simple time-domain computations in place of conventional computationally intensive frequency domain methods. Our method uses a chirp stimulus and an average of absolute value to extract energy in different frequency bins. For an N-0-size spectrum, this enables a reduction of computational complexity from N-0 ln N-0 multiply-accumulates (using an FFT) to N-0 accumulates. This makes it an attractive strategy for BIST. We present the theoretical basis, test case simulations, and a comparison with the FFT method.