Vernier principle based optical double racetrack resonator (ODRR) with its constituent material as Silicon-on-insulator (SOI) having effective refractive index as 1.71 has been utilized for obtaining optical filter having wider free spectral range (FSR). Here delay line signal processing technique in Z-domain and Mason's gain formula are being used for analyzing the racetrack resonator. A free spectral range of 10.04THz is obtained for drop port which is very much comparable with the results with similar kind of architecture using other methods of analysis. Here interstitial spurious transmission is almost -100dB with negligible resonance loss. Group delay, dispersion characteristics and Finesse are also determined from this architecture. © 2015 IEEE.