Generation and Digital Correlation of Barker Code for Radars and Communication Systems

Abstract: The recent advances in semiconductor technology allow the realization of low cost hardware architecture for implementing the correlation codes, Barker and Taylor codes, with different lengths. There are many types of modulations used for pulse compression, but two that have seen wide applications are the Linear Frequency Modulation (LFM) and the phase-coded pulse. In this paper, we investigated the second one by the design of Barker code generator circuit using two different configurations. This is very important for modern radar transmitters and communication systems. Such codes enable the design of pulse compression circuit in sophisticated receivers to make use of their benefits in improving the resolution in angles and range as well as enhancement of signal to noise ratio(S / N) . In addition, we addressed the design of 7-bit digital correlator to focus on its correlation property. It is interesting to go beyond the theoretical study and analysis by applying the package of simulation to shed the light on all the details in time domain. Specifically, the binary phase variations (0,  ) between the modulating signal ,correlation codes, and the carrier signal. Taylor code ,double Barker code of length: 26, has good autocorrelation properties and we have found it with low cross- correlation. Therefore it is suitable in multi-user environment and to encode the carrier signal of long duration for transmitted pulses. Its combination with Barker code of length:13 leads to form different operating modes which is applied to fire control and early warning radars. Also it keeps constant side lobe level with low value which alleviates the effect of undesired received signals.

Keywords: Barker Code Generator; Taylor Code; Auto Correlation Function; Digital Correlator; Phase coding; Pulse Compression