Signal Source
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Signal generator: generates a variety of waveforms.
Supports an output of type complex, float, int, and short
Parameters
(R): Run-time adjustable
- Sample Rate (R)
- Default value: samp_rate
- Sample rate (fs) is the average number of samples obtained in one second. Its units are samples per second or hertz e.g. 48,000 sample rate is 48 kHz.
- Waveform (R)
- options: [Constant, Sine, Cosine, Square, Triangle, Saw Tooth]
- For selection with a variable, the following values should be used:
- Constant = 100
- Sine = 101
- Cosine = 102
- Square = 103
- Triangle = 104
- Sawtooth = 105
- Frequency (R)
- Frequency of the waveform (default: 1000)
- Amplitude (R)
- Amplitude of the output (default: 1)
- Offset (R)
- Offset from zero (default: 0)
- Initial Phase (Radians) (R)
- Default: 0
Message Ports
- cmd
- The 'cmd' message port accepts message pairs.
- 'freq' . float value
- 'ampl' . float value
- 'phase' . float value
- 'offset' . float value
- For GNU Radio 3.8, the messages dont work correctly with pairs, but they do work fine with a dictionary. This issue is explained here.
- The amplitude of the signal source can be changed to 0.5 by adding the following PMT to the message strobe block.
pmt.dict_add(pmt.make_dict(), pmt.intern("ampl"), pmt.from_double(0.5))
- The above command creates a dictionary and adds a pmt pair of ("ampl", 0.5) to the dictionary.
- freq
- The value of frequency in the signal source can be changed by connecting a message strobe. The Message PMT parameter can be set to pmt.from_float(new_freq). In this way, the frequency of the signal source will be changed to new_freq value after the specified period in the message strobe.
- The 'freq' message port has been
deprecated in 3.9in favor of the 'cmd' message port.
Example Flowgraph
This flowgraph is for version 3.9+.
Example Output
Types of Waveforms:
Cosine (complex):
Constant:
Square:
Triangle:
Sawtooth:
Source Files
- C++ files
- sig_source_impl.cc
- Header files
- sig_source_impl.h
- Block definition
- analog_sig_source_x.block.yml