Random Source

Generates a number of samples of random numbers of [min, max) meaning the max value won't be included. Repeat samples if specified. Useful for creating bytes of information for testing a modulator.

Ex: With min=0 and max=2, the sequence 01110101... of length num_samps will be generated.

Supports an output of type int, short, and byte.

This block differs from Random Uniform Source:

This block uses Numpy to generate a fixed random vector of values. The output of this block repeats every num_samps, and hence has high autocorrelation with that period.
The algorithms used to generate the random numbers differ, as well: Numpy, and hence Random Source, use MT19937¹, whereas the Random Uniform Source uses XOROSHIRO128+, which has a period of 2¹²⁸-1 and is hence to be preferred if autocorrelation over a window of length num_samps is relevant.

Parameters

(R): Run-time adjustable

Output type

Available options are int, short or byte

Minimum

The lower limit of the range of generated values (included in the output)

Maximum

The upper limit of the range of generated values (not included in the output)

Num Samples

Total number of samples that are generated in the output

Repeat

Yes/No

Example Flowgraph

Source Files

C++ files

TODO

Header files

TODO

Public header files

TODO

Block definition

TODO

Computational Performance

File:Benchmark prng.grc done on a Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz, 8GB RAM VOLK 2.5.0, GNU Radio 3.10.0.0-rc1, Linux 5.15.11

Block	Number of Samples / Period after which samples repeat	Throughput (in 106 samples per second)	Note
Random Source	1000	838	default setting
Random Source	220=1,048,576	824
Random Source	224	812
Random Source	228	813	Initialization of the random vector needs nearly 30s, eats 4GB of RAM
Random Uniform Source	2128-1	282

---

¹ The slightly superior randomness properties of MT19937 over XOROSHIRO128+ don't matter within the maximum size of a vector of values on a PC, and are generally unnoticable in an SDR contex