High Precision Broadband Direct-Spread Signal Delay Control Based on Phase Controlled Waveform Hermite Interpolation

Abstract

When generating simulation satellite navigation signal, the delay of the broadband direct-spread satellite navigation signal needs to be controlled with high precision. A widely used signal delay control method was changing the phase of the NCO which drives the signal generation. But the signal delay variation that less than a NCO system clock cycle can’t be observed at every part of the signal at real time, when it control by the NCO method. The delay less than a NCO system clock cycle can only be observed by matching correlation. Therefore, this delay control can only be defined as an “average” delay control method, and it can’t be calibrated by using simple time domain measurement method, which is wildly used for calibrating the delay control of the VFD (Variable Fraction Delay) filter method that consumes a large amount of hardware resources. A high precision delay control method for broadband direct-spread signal based on NCO phase controlled waveform Hermite interpolation is proposed, which achieves the same time domain measurement performance with the VFD filter method at the precision of 10 ps level, but consumes much more less hardware resources. At last, the testing results verify the validity of the theoretical method.