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-rwxr-xr-xapps/grgsm_trx14
-rw-r--r--python/trx/radio_if.py14
2 files changed, 26 insertions, 2 deletions
diff --git a/apps/grgsm_trx b/apps/grgsm_trx
index 1c0581f..45312e6 100755
--- a/apps/grgsm_trx
+++ b/apps/grgsm_trx
@@ -25,6 +25,8 @@ import signal
import getopt
import sys
+from gnuradio import eng_notation
+
from grgsm.trx import ctrl_if_bb
from grgsm.trx import radio_if
from grgsm.trx import fake_pm
@@ -45,6 +47,7 @@ class Application:
# PHY specific
phy_sample_rate = 4 * 1625000 / 6
+ phy_freq_offset_hz = None
phy_tx_antenna = "TX/RX"
phy_rx_antenna = "RX2"
phy_rx_gain = 30
@@ -67,6 +70,10 @@ class Application:
self.bind_addr, self.remote_addr,
self.base_port)
+ # Optional frequency offset
+ if self.phy_freq_offset_hz is not None:
+ self.radio.freq_offset_hz = self.phy_freq_offset_hz
+
# Power measurement emulation
# Noise: -120 .. -105
# BTS: -75 .. -50
@@ -110,6 +117,7 @@ class Application:
" -G --tx-gain Set TX gain (default %d)\n" \
" --rx-antenna Set RX antenna (default %s)\n" \
" --tx-antenna Set TX antenna (default %s)\n" \
+ " --freq-offset Shift baseband freq. (e.g. -500M)\n" \
" --ppm Set frequency correction (default %d)\n"
print(s % (
@@ -128,7 +136,7 @@ class Application:
"i:b:p:a:s:g:G:h",
["help", "remote-addr=", "bind-addr=", "base-port=",
"device-args=", "sample-rate=", "rx-gain=", "tx-gain=",
- "ppm=", "rx-antenna=", "tx-antenna="])
+ "ppm=", "rx-antenna=", "tx-antenna=", "freq-offset="])
except getopt.GetoptError as err:
# Print(help and exit)
self.print_help()
@@ -167,6 +175,10 @@ class Application:
self.phy_tx_antenna = v
elif o in ("--ppm"):
self.phy_ppm = int(v)
+ elif o in ("--freq-offset"):
+ # Convert /\d+(\.\d+)?(M|k)?/ to Hz
+ offset_hz = eng_notation.str_to_num(v)
+ self.phy_freq_offset_hz = offset_hz
def sig_handler(self, signum, frame):
print("Signal %d received" % signum)
diff --git a/python/trx/radio_if.py b/python/trx/radio_if.py
index d2afcf6..407e724 100644
--- a/python/trx/radio_if.py
+++ b/python/trx/radio_if.py
@@ -4,7 +4,7 @@
# GR-GSM based transceiver
# Follow graph implementation
#
-# (C) 2016-2017 by Vadim Yanitskiy <axilirator@gmail.com>
+# (C) 2016-2018 by Vadim Yanitskiy <axilirator@gmail.com>
# (C) 2017 by Piotr Krysik <ptrkrysik@gmail.com>
#
# All Rights Reserved
@@ -29,6 +29,7 @@ import grgsm
from math import pi
+from gnuradio import eng_notation
from gnuradio import digital
from gnuradio import blocks
from gnuradio import uhd
@@ -59,6 +60,7 @@ class dict_toggle_sign(gr.basic_block):
class radio_if(gr.top_block):
# PHY specific variables
+ freq_offset_hz = None
rx_freq = 935e6
tx_freq = 890e6
osr = 4
@@ -274,11 +276,21 @@ class radio_if(gr.top_block):
return self.ppm / 1.0e6 * 2 * pi * fc / self.sample_rate
def set_rx_freq(self, fc):
+ if self.freq_offset_hz is not None:
+ fc += self.freq_offset_hz
+ print("[#] Shifting RX freq. to %s (offset is %s)"
+ % (eng_notation.num_to_str(fc),
+ eng_notation.num_to_str(self.freq_offset_hz)))
self.phy_src.set_center_freq(fc, 0)
self.rotator_src.set_phase_inc(self.calc_phase_inc(fc))
self.rx_freq = fc
def set_tx_freq(self, fc):
+ if self.freq_offset_hz is not None:
+ fc += self.freq_offset_hz
+ print("[#] Shifting TX freq. to %s (offset is %s)"
+ % (eng_notation.num_to_str(fc),
+ eng_notation.num_to_str(self.freq_offset_hz)))
self.phy_sink.set_center_freq(fc, 0)
self.rotator_sink.set_phase_inc(-self.calc_phase_inc(fc))
self.tx_freq = fc