Crash when selecting FSK in modulator in certain conditions

[whitequark]

Expected Behavior

Crash when selecting FSK in modulator in certain conditions.

Actual Behavior

No crash.

Steps To Reproduce

1. Open project nrfreverse.zip
2. Click on 'Generator'
3. Select 'LimeSDR-20200125_083302-2_402GHz-8MSps-2MHz'
4. Click 'Edit ...'
5. Under 'Modulation', select 'ASK'
6. Under 'Modulation', select 'FSK'
7. Observe crash:

raceback (most recent call last):
  File "/home/whitequark/Projects/urh/src/urh/controller/dialogs/ModulatorDialog.py", line 491, in on_modulation_type_changed
    self.set_default_modulation_parameters()
  File "/home/whitequark/Projects/urh/src/urh/controller/dialogs/ModulatorDialog.py", line 351, in set_default_modulation_parameters
    self.current_modulator.parameters = self.current_modulator.get_default_parameters()
  File "/home/whitequark/Projects/urh/src/urh/signalprocessing/Modulator.py", line 244, in get_default_parameters
    for i in range(self.modulation_order):
TypeError: 'float' object cannot be interpreted as an integer

Platform Specifications

• OS: Debian buster
• URH version: 5460cf5851ae8
• Python version: 3.7
• Installed via git

Workaround

With the following patch, modulator seems to work OK and produce signals that are demodulated by my nRF24L01+:

diff --git a/src/urh/signalprocessing/Modulator.py b/src/urh/signalprocessing/Modulator.py
index 9cdd7942..fc46b7e0 100644
--- a/src/urh/signalprocessing/Modulator.py
+++ b/src/urh/signalprocessing/Modulator.py
@@ -241,7 +241,7 @@ class Modulator(object):
             parameters = np.linspace(0, 100, self.modulation_order, dtype=np.float32)
         elif self.is_frequency_based:
             parameters = []
-            for i in range(self.modulation_order):
+            for i in range(int(self.modulation_order)):
                 parameters.append((i + 1) * self.carrier_freq_hz / self.modulation_order)
         elif self.is_phase_based:
             step = 360 / self.modulation_order

But from looking at the code this doesn't seem like the right fix to me.

[whitequark]

Thanks!