spectrum of a signal

i have a vector matrix of a signal, how to find numerical value figure of merit of spectrum, 
such as 3dm main lobe width, highest side lobe level, main lobe power. Fs, sampling frequency 6 MHz.
My matrix is ftw = [-0.0001 + 0.0000i
   0.0009 + 0.0003i
   0.0032 + 0.0015i
   0.0057 + 0.0054i
   0.0081 + 0.0120i
   0.0080 + 0.0221i
   0.0032 + 0.0348i
  -0.0073 + 0.0485i
  -0.0257 + 0.0613i
  -0.0518 + 0.0699i
  -0.0862 + 0.0707i
  -0.1266 + 0.0599i
  -0.1691 + 0.0337i
  -0.2081 - 0.0104i
  -0.2380 - 0.0725i
  -0.2509 - 0.1505i
  -0.2404 - 0.2404i
  -0.2009 - 0.3350i
  -0.1289 - 0.4245i
  -0.0248 - 0.4982i
   0.1080 - 0.5442i
   0.2614 - 0.5527i
   0.4232 - 0.5159i
   0.5797 - 0.4297i
   0.7146 - 0.2963i
   0.8130 - 0.1206i
   0.8622 + 0.0848i
   0.8527 + 0.3052i
   0.7803 + 0.5214i
   0.6482 + 0.7148i
   0.4642 + 0.8680i
   0.2421 + 0.9664i
  -0.0001 + 0.9998i
  -0.2422 + 0.9664i
  -0.4641 + 0.8681i
  -0.6482 + 0.7146i
  -0.7808 + 0.5215i
  -0.8527 + 0.3052i
  -0.8623 + 0.0850i
  -0.8133 - 0.1208i
  -0.7151 - 0.2961i
  -0.5797 - 0.4297i
  -0.4232 - 0.5157i
  -0.2615 - 0.5528i
  -0.1083 - 0.5443i
   0.0243 - 0.4980i
   0.1287 - 0.4245i
   0.2008 - 0.3348i
   0.2404 - 0.2404i
   0.2508 - 0.1505i
   0.2377 - 0.0724i
   0.2078 - 0.0104i
   0.1685 + 0.0337i
   0.1261 + 0.0599i
   0.0861 + 0.0708i
   0.0519 + 0.0699i
   0.0252 + 0.0615i
   0.0070 + 0.0485i
  -0.0037 + 0.0349i
  -0.0082 + 0.0222i
  -0.0082 + 0.0120i
  -0.0062 + 0.0055i
  -0.0032 + 0.0015i
  -0.0010 + 0.0004i]