Time discriminator of spread spectrum signal with minimum frequency modulation in format of MSK-BOC

This article is about the time discriminator of spread spectrum signal with minimum frequency modulation in format of MSK-BOC.

The structure of the coherent time discriminator was considered. The synchronous detector has two quadrature channels to highlight quadrature video-frequency noise-like signals from the input observation. Multiplying results of the quadrature components and the reference signals are combined and then are integrated over an interval equal to the period of noise-like signal repetition, producing an error signal for the current period. After reading and memorizing the current count, the integrator is reset to zero and goes up to the next frame formation. The output error signal counts of the discriminator fed to the loop filter and to the reference signal generator of delay locked loop.

The noise immunity analysis of considered discriminator has been made, using the equivalent temporal fluctuations as the criterion scattering, which are at the discriminator input of tracking system-s linearized model.

Expression for the discriminatory characteristics of coherent time discriminator was obtained.

It has been shown, that signals with MSK-DOC (n, n) format provide significant advantages in delay measurement accuracy compared to traditional MSK signal (a win by the mean square error is two times) by allowing to simplify the implementation of coherent time discriminator.