Re: [Discuss-gnuradio] digital noise input

[Eric Blossom]

On Fri, Nov 17, 2006 at 07:13:05PM -0800, Oussama Sekkat wrote:
> Hi,
> 
> I am still trying to measure the digital output noise (from the LFRX_A
> daughterboard).

Another random thought:

Since you are using the LFRX and it's DC coupled you must turn off
the ADC DC offset removal control loop in the FPGA.

  /*!
   * \brief Enable/disable automatic DC offset removal control loop in FPGA
   *
   * \param bits  which control loops to enable
   * \param mask  which \p bits to pay attention to
   *
   * If the corresponding bit is set, enable the automatic DC
   * offset correction control loop.
   *
   * <pre>
   * The 4 low bits are significant:
   *
   *   ADC0 = (1 << 0)
   *   ADC1 = (1 << 1)
   *   ADC2 = (1 << 2)
   *   ADC3 = (1 << 3)
   * </pre>
   *
   * By default the control loop is enabled on all ADC's.
   */
  bool set_dc_offset_cl_enable(int bits, int mask);


In python:

  u.set_dc_offset_cl_enable(0x0, 0x3)


Eric