diff --git a/brukeropusreader/opus_data.py b/brukeropusreader/opus_data.py
index fd3e648..6e2e13f 100644
--- a/brukeropusreader/opus_data.py
+++ b/brukeropusreader/opus_data.py
@@ -4,14 +4,6 @@ from numpy import linalg
 from scipy.interpolate import interp1d
 
 
-class NoInterpolatedDataException(Exception):
-    pass
-
-
-class WrongWavelengthsInConf(Exception):
-    pass
-
-
 class OpusData(object):
     def __init__(self, raw_data, interp=None, meta=None):
         self.raw_data = raw_data
@@ -25,38 +17,13 @@ class OpusData(object):
             dist = linalg.norm(y_r - self.raw_data[1], ord=1)
             print("L1 distance between series:", dist)
 
-    def gen_interp_waves(self, conf):
-        wunit = (conf.wave_start - conf.wave_end) / (float(conf.iwsize - 1))
-        a = conf.wave_start + wunit
-        iwavenumber = [0] * conf.iwsize
-        for i in range(len(iwavenumber)):
-            a -= wunit
-            iwavenumber[i] = a
-        return iwavenumber
-
-    def interpolate_spectra(self, conf):
+    def interpolate(self, start, stop, num):
         xav, yav = self.raw_data[0], self.raw_data[1]
-        ab_wavenumbers = self.raw_data[0]
-        iwavenumber = self.gen_interp_waves(conf)
-
-        xa_min = min(ab_wavenumbers)
-        xa_max = max(ab_wavenumbers)
-        n_interp = conf.iwsize
-        yi = []
-
-        f2 = interp1d(xav, yav, kind='cubic', assume_sorted=True)
-
-        for k in range(n_interp):
-            if iwavenumber[k] < xa_min:
-                if k == n_interp - 1:
-                    yi.append(yav[0])
-                else:
-                    print("Wrong wavelengths for interpolating data")
-            elif iwavenumber[k] > xa_max:
-                if k == 0:
-                    yi.append(yav[-1])
-                else:
-                    raise WrongWavelengthsInConf()
-            else:
-                yi.append(f2(iwavenumber[k]))
-        return iwavenumber, yi
+        iwavenumber = np.linspace(start,
+                                  stop,
+                                  num)
+        f2 = interp1d(xav, yav,
+                      kind='cubic',
+                      assume_sorted=True,
+                      fill_value='extrapolate')
+        return iwavenumber, f2(iwavenumber)