diff --git a/SpecDisperser/SpecDisperser.py b/SpecDisperser/SpecDisperser.py
index 6c065c0db00d2656d098c4d66732df553cbaeb86..a5240cea5d5080fdc35883a1e6092866c66122d6 100644
--- a/SpecDisperser/SpecDisperser.py
+++ b/SpecDisperser/SpecDisperser.py
@@ -60,7 +60,7 @@ def rotate90(array_orig=None, xc=0, yc=0, isClockwise=0):
 
 class SpecDisperser(object):
     def __init__(self, orig_img=None, xcenter=0, ycenter=0, origin=[100, 100], tar_spec=None, band_start=2550,
-                 band_end=10000, isAlongY=0, conf='../param/CONF/csst.conf', gid=0):
+                 band_end=10000, isAlongY=0, conf='../param/CONF/csst.conf', gid=0, deltLamb = 0.01):
         """
         orig_img: normal image,galsim image
         xcenter, ycenter: the center of galaxy in orig_img
@@ -97,6 +97,7 @@ class SpecDisperser(object):
         self.band_start = band_start
         self.band_end = band_end
         self.spec = tar_spec
+        self.deltLamb = deltLamb
 
         self.beam_flux = OrderedDict()
 
@@ -132,7 +133,7 @@ class SpecDisperser(object):
         lam_index = argsort(lam_beam)
         conf_sens = self.grating_conf.sens[beam]
 
-        lam_intep = np.linspace(self.band_start, self.band_end, int((self.band_end - self.band_start) / 0.5))
+        lam_intep = np.linspace(self.band_start, self.band_end, int((self.band_end - self.band_start) / self.deltLamb))
 
         thri = interpolate.interp1d(conf_sens['WAVELENGTH'], conf_sens['SENSITIVITY'])
         spci = interpolate.interp1d(self.spec['WAVELENGTH'], self.spec['FLUX'])
diff --git a/SpecGen/SpecGenerator.py b/SpecGen/SpecGenerator.py
index 106298715d37f1caed7def3a3389dc5b666c00f3..8aae91678fd6a8f17fa447283b6bd78ff967fb51 100644
--- a/SpecGen/SpecGenerator.py
+++ b/SpecGen/SpecGenerator.py
@@ -21,6 +21,7 @@ import random
 
 from astropy.table import Table
 import matplotlib.pyplot as plt
+import time
 
 import mpi4py.MPI as MPI
 
@@ -76,13 +77,13 @@ class SpecGenerator(object):
         return SED
 
 
-    def generateSpec1dforGal(self, s_n = 1.0, re = 1, pa = 90,q_ell = 0.6,limitfluxratio=0.9):
+    def generateSpec1dforGal(self, s_n = 1.0, re = 1, pa = 90,q_ell = 0.6,limitfluxratio=0.9,deltLamb = 0.01):
 
         specConfile = self.config.conFiles[self.grating]
 
         throughput_f = self.config.senFisle[self.grating] + self.config.orderIDs[self.beam] + '.fits'
 
-        sed = self.generateSEDfromFiles(self.sedFile,2500,10000,0.01)
+        sed = self.generateSEDfromFiles(self.sedFile,2500,10000,deltLamb)
 
         x_nominal = int(np.floor(self.xcenter + 0.5))
         y_nominal = int(np.floor(self.ycenter + 0.5))
@@ -118,7 +119,7 @@ class SpecGenerator(object):
                                             ycenter=y_nominal, origin=origin_star,
                                             tar_spec=sed,
                                             conf=specConfile,
-                                            isAlongY=0)
+                                            isAlongY=0, deltLamb = deltLamb/2.)
 
         spec_orders = sdp.compute_spec_orders()
         
@@ -130,6 +131,7 @@ class SpecGenerator(object):
 
         Aimg_ = Aimg_ + (self.skybg + self.dark)*self.t*self.expNum
 
+        np.random.seed(int(time.time()))
         Aimg_ = np.random.poisson(Aimg_)
         for i in np.arange(self.expNum):
             Aimg_ = self.addReadoutNois(img = Aimg_, readout = self.readout)
@@ -253,13 +255,13 @@ class SpecGenerator(object):
         return specTab, Aimg, stamp.array, saturePix
 
 
-    def generateSpec1dforStar(self,limitfluxratio = 0.8):
+    def generateSpec1dforStar(self,limitfluxratio = 0.8, deltLamb = 0.01):
         import matplotlib.pyplot as plt
         specConfile = self.config.conFiles[self.grating]
 
         throughput_f = self.config.senFisle[self.grating] + self.config.orderIDs[self.beam] + '.fits'
 
-        sed = self.generateSEDfromFiles(self.sedFile,2500,10000,0.01)
+        sed = self.generateSEDfromFiles(self.sedFile,2500,10000,deltLamb)
 
         x_nominal = int(np.floor(self.xcenter + 0.5))
         y_nominal = int(np.floor(self.ycenter + 0.5))
@@ -293,7 +295,7 @@ class SpecGenerator(object):
                                             ycenter=y_nominal, origin=origin_star,
                                             tar_spec=sed,
                                             conf=specConfile,
-                                            isAlongY=0)
+                                            isAlongY=0,deltLamb = deltLamb/2.)
 
         spec_orders = sdp.compute_spec_orders()
         
@@ -304,7 +306,7 @@ class SpecGenerator(object):
         Aimg_ = Aimg_orig
 
         Aimg_ = Aimg_ + (self.skybg + self.dark)*self.t*self.expNum
-
+        np.random.seed(int(time.time()))
         Aimg_ = np.random.poisson(Aimg_)
         for i in np.arange(self.expNum):
             Aimg_ = self.addReadoutNois(img = Aimg_, readout = self.readout)
@@ -424,6 +426,7 @@ class SpecGenerator(object):
         return specTab, Aimg, stamp.array, saturePix
 
     def addReadoutNois(self, img = None, readout = 5):
+        random.seed(time.time())
         for i in range(img.shape[0]):
             for j in range(img.shape[1]):
                 img[i,j] += round(random.gauss(mu = 0, sigma = readout))