diff --git a/python/__init__.py b/python/__init__.py
index f29e154..9e99e72 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -55,6 +55,7 @@
 from gsm_bcch_ccch_demapper import gsm_bcch_ccch_demapper
 from gsm_bcch_ccch_sdcch4_demapper import gsm_bcch_ccch_sdcch4_demapper
 from gsm_sdcch8_demapper import gsm_sdcch8_demapper
+from gsm_gmsk_mod import gsm_gmsk_mod
 from fn_time import *
 from txtime_bursts_tagger import *
 #from ctrl_if import *
diff --git a/python/transmitter/gsm_gmsk_mod.py b/python/transmitter/gsm_gmsk_mod.py
new file mode 100644
index 0000000..e8ecc7a
--- /dev/null
+++ b/python/transmitter/gsm_gmsk_mod.py
@@ -0,0 +1,69 @@
+# -*- coding: utf-8 -*-
+##################################################
+# GNU Radio Python Flow Graph
+# Title: GMSK Modulator for GSM
+# Author: Piotr Krysik
+# Description: GMSK Modulator for GSM
+# Generated: Wed Sep 20 21:12:04 2017
+##################################################
+
+from gnuradio import blocks
+from gnuradio import digital
+from gnuradio import gr
+from gnuradio.analog import cpm
+from gnuradio.filter import firdes
+import grgsm
+
+class gsm_gmsk_mod(grgsm.hier_block):
+
+    def __init__(self, BT=4, pulse_duration=4, sps=4):
+        gr.hier_block2.__init__(
+            self, "GMSK Modulator for GSM",
+            gr.io_signature(1, 1, gr.sizeof_char*1),
+            gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
+        )
+
+        ##################################################
+        # Parameters
+        ##################################################
+        self.BT = BT
+        self.pulse_duration = pulse_duration
+        self.sps = sps
+
+        ##################################################
+        # Blocks
+        ##################################################
+        self.digital_gmskmod_bc_0 = digital.gmskmod_bc(sps, pulse_duration, BT)
+        self.digital_diff_decoder_bb_0 = digital.diff_decoder_bb(2)
+        self.digital_chunks_to_symbols_xx_0 = digital.chunks_to_symbols_bf(([1,-1]), 1)
+        self.blocks_tagged_stream_multiply_length_0 = blocks.tagged_stream_multiply_length(gr.sizeof_gr_complex*1, "packet_len", sps)
+        self.blocks_float_to_char_0 = blocks.float_to_char(1, 1)
+
+        ##################################################
+        # Connections
+        ##################################################
+        self.connect((self.blocks_float_to_char_0, 0), (self.digital_gmskmod_bc_0, 0))    
+        self.connect((self.blocks_tagged_stream_multiply_length_0, 0), (self, 0))    
+        self.connect((self.digital_chunks_to_symbols_xx_0, 0), (self.blocks_float_to_char_0, 0))    
+        self.connect((self.digital_diff_decoder_bb_0, 0), (self.digital_chunks_to_symbols_xx_0, 0))    
+        self.connect((self.digital_gmskmod_bc_0, 0), (self.blocks_tagged_stream_multiply_length_0, 0))    
+        self.connect((self, 0), (self.digital_diff_decoder_bb_0, 0))    
+
+    def get_BT(self):
+        return self.BT
+
+    def set_BT(self, BT):
+        self.BT = BT
+
+    def get_pulse_duration(self):
+        return self.pulse_duration
+
+    def set_pulse_duration(self, pulse_duration):
+        self.pulse_duration = pulse_duration
+
+    def get_sps(self):
+        return self.sps
+
+    def set_sps(self, sps):
+        self.sps = sps
+        self.blocks_tagged_stream_multiply_length_0.set_scalar(self.sps)