As essential specifications of correlation domain for signal quality evaluation, distortions of the S-curve, including bias and slope distortions of the zero-crossing point, are usually selected as indicators of optimisation in the process of designing the channels of receivers or navigation satellites. Focusing on this issue, we present a detailed analysis of slope distortion in the presence of group delay and amplitude distortions. After validating the theoretical results, we present further discussions about the impacts of different group delay terms on slope distortions. The results indicate that both the odd-order and the even-order terms have impacts on the slope distortion, and higher odd-order terms have less slope distortion compared with the lower odd-order terms. These results are useful for evaluating the slope distortion from the group delay and guiding improvement in design of the channel.

Pb(Sc1/2Ta1/2)O3 (PST) relaxor ferroelectric ceramics were investigated widely in the past decades for their excellent pyroelectric, ferroelectric and dielectric properties and comprehensive applications in uncooled focal plane arrays infrared detectors and other electronic devices. However, some other ferroelectrics could be added into the PST ceramics to form the complex perovskite ferroelectrics with better electric properties. In this paper, (1-x)PST-xPZT(PSTZT) relaxor ferroelectric ceramics were prepared by wolframite precursor process (named two-step -sintering method, TSSM). The experiment results showed that the PSTZT ceramics with pure perovskite structure could be prepared by using TSSM. The temperature dependence of permittivity and dielectric loss of PSTZT ceramics were investigated in detail, which indicated that PSTZT ceramics showed partly diffusive phase transition with little frequency dispersion. The dielectric and pyroelectric properties of PSTZT ceramics were also investigated and discussed.