Delay discriminator for Coran-C radio navigation system - is able to suppress echo and scattering pulses using specified elliptic and two pole filters

摘要

The delay discriminator, for LORAN-C and other radio navigation systems, discriminates between rapidly following pulses in the same frequency band as well as between pulses in different bands but close together is allows the suppression of echoes and scattering effects. The navigation receiver output is coupled to an elliptic filter (A) whose own output is amplified and passed to a two-pole synchronous filter (B). The latter filter consists of two one-pole filters which are separated by an amplifier. The elliptic filter has a step characteristic centered on the centre frequency whilst the two-pole filter has a continuous curve enclosing the step characteristics of the elliptical filter.