removed dc offset

Author: GvozdevLeonid

python_hackrf/pyhackrf_tools/pyhackrf_sweep.pyx

@@ -117,6 +117,7 @@ cpdef int sweep_callback(c_pyhackrf.PyHackrfDevice device, cnp.ndarray[cnp.int8_
     cdef uint64_t start_frequency = device_data['start_frequency']
 
     cdef cnp.ndarray fftOut
+    cdef cnp.ndarray raw_iq
     cdef cnp.ndarray pwr
 
     cdef uint32_t fft_1_start = 1 + (fft_size * 5) // 8
@@ -160,7 +161,9 @@ cpdef int sweep_callback(c_pyhackrf.PyHackrfDevice device, cnp.ndarray[cnp.int8_
 
         index += (pyhackrf.PY_BYTES_PER_BLOCK - data_length)
 
-        fftOut = fft((buffer[index:index + data_length:2] / 128 + 1j * buffer[index + 1:index + data_length:2] / 128) * window)
+        raw_iq = buffer[index:index + data_length:2] / 128 + 1j * buffer[index + 1:index + data_length:2] / 128
+        raw_iq -= raw_iq.mean()
+        fftOut = fft(raw_iq * window)
         pwr = np.log10(np.abs(fftOut * norm_factor) ** 2) * 10.0
 
         if sweep_style == pyhackrf.py_sweep_style.LINEAR: