Left upper: observed 3 mm band spectrum toward the center of NGC 1068 from 84.0 to 92.2 GHz. We mark each identified spectral line, using its rest frequency. The original RMS is about 1.50 mK at a frequency resolution of 0.195 MHz. The RMS is 0.45 mK after smoothing to the frequency resolution of 5.273 MHz at the rest frequency of 86.847 GHz. Eighteen lines were identified in this band, except for C₂ H (1–0), which rangesfrom 87.284 to 87.447 GHz. Right upper: CH₃OH (5_−1,5–4_0,4) (filled yellow) and Gaussian fitting profile (red line). The RMS is 0.41 mK at a velocity resolution of 12.47 km s⁻¹. Left lower: SiO (2–1), H¹³CO⁺ (1–0), and HCO (1_0,1–0_0,0) (filled yellow), overlaid with Gaussian fitting profiles (red for SiO, blue for H¹³ CO⁺, light blue forHCO, and green for the combination of the three components). The RMS is 0.37 mK at the velocity resolution of 24.27 km s⁻¹. Right lower: SiO (5–4) (blue line and filled yellow) overlaid with SiO (2–1) (red line). The RMS is 0.94 mK for SiO (5–4) at a velocity resolution of 21.85 km s⁻¹, while it is 0.32 mK for SiO (2–1) at a velocity resolution of 24.27 km s⁻¹.