diff --git a/spacelab_transmitter/gmsk.py b/spacelab_transmitter/gmsk.py
index 8d53460..1bf86eb 100644
--- a/spacelab_transmitter/gmsk.py
+++ b/spacelab_transmitter/gmsk.py
@@ -52,7 +52,7 @@ def modulate(self, data, L=_GMSK_DEFAULT_OVERSAMPLING_FACTOR):
         :return: dur: Signal duration in seconds
         """
         I, Q, fs, dur = self.get_iq(data, L)
-        s_complex = np.complex64(I) - np.complex64(1j)*np.complex64(Q)  # Complex baseband representation
+        s_complex = I + 1j*Q    # Complex baseband representation
 
         return s_complex, fs, dur
 
@@ -71,14 +71,7 @@ def get_iq(self, data, L=_GMSK_DEFAULT_OVERSAMPLING_FACTOR):
         # Convert to array of bits
         data = self._int_list_to_bit_list(data)
 
-        data_buff = list()
-        for i in data:
-            if i == 0:
-                data_buff.append(1)
-            else:
-                data_buff.append(0)
-
-        data = np.array(data_buff)
+        data = np.array(data)
 
         # Timing parameters
         fc = self._baudrate                         # Carrier frequency = Data transfer rate in bps
@@ -90,7 +83,7 @@ def get_iq(self, data, L=_GMSK_DEFAULT_OVERSAMPLING_FACTOR):
         k = 1                                       # Truncation length for Gaussian LPF
         h_t = self._gaussian_lpf(Tb, L, k)          # Gaussian LPF with BT=0.25
         b_t = np.convolve(h_t, c_t, 'full')         # Convolve c(t) with Gaussian LPF to get b(t)
-        bnorm_t = b_t/max(abs(b_t))                 # Normalize the output of Gaussian LPF to +/-1
+        bnorm_t = b_t/np.max(np.abs(b_t))           # Normalize the output of Gaussian LPF to +/-1
 
         # Integrate to get phase information
         h = 0.5                                     # Modulation index (GMSK = 0.5)
diff --git a/spacelab_transmitter/usrp.py b/spacelab_transmitter/usrp.py
index 62b6985..d6539d3 100644
--- a/spacelab_transmitter/usrp.py
+++ b/spacelab_transmitter/usrp.py
@@ -51,6 +51,7 @@ def transmit(self, samples, dur, rate, freq):
 
         :return: True/False if successful or not.
         """
+        samples = samples.astype(np.complex64)
         samples = signal.resample_poly(samples, self._sample_rate, rate)
 
         if self._usrp.send_waveform(samples, dur, freq, self._sample_rate, [0], self._gain):
diff --git a/spacelab_transmitter/version.py b/spacelab_transmitter/version.py
index b31a74f..40e8b49 100644
--- a/spacelab_transmitter/version.py
+++ b/spacelab_transmitter/version.py
@@ -24,7 +24,7 @@
 __copyright__   = "Copyright The SpaceLab-Transmitter Contributors"
 __credits__     = ["Gabriel Mariano Marcelino, Vitória Beatriz Bianchin"]
 __license__     = "GPLv3"
-__version__     = "0.4.10"
+__version__     = "0.4.11"
 __maintainer__  = "Gabriel Mariano Marcelino - PU5GMA"
 __email__       = "gabriel.mm8@gmail.com"
 __status__      = "Development"