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matlabgnuradiognuradio-companion

the block "complex to Arg" in gnuradio

I want to realize the block "complex to Arg" which is a block in gnuradio in matlab.

I use the command angle in matlab. But some results aren't same as in gnuradio.

For example,

In matlab,

angle(1.646236600879293e+03 + 8.043715071772031e+00i) = 0.004886084452240

while in gnuradio,

the block returns 0.00294448575004935.

Can someone explain it? Or give me a hint on the command of matlab.

Solution

  • According to this discussion gnuradio does not use the libmath atan2 function for performance reasons. I believe matlab uses the libmath function instead. They also say that the error is larger in 0 or Pi/2, which is your case. Thus gnuradio arg and matlab angle are both correct, they just link to different implementations (of atan), with different performance and precision.