The SSFS_Ctrl Acl version have been upgraded to Acl v0r33p1 to use a new facility for the filter definition(last parameter of the ACL_FILTER_SET keyword).

Today the 3rd boost filter use only real low second order poles and  zeros at low frequency : 

• ACL_FILTER_SET         "SSFS_B4_flt_boost"  2        -7.8        2000    20
• ACL_FILTER_POLES    SSFS_B4_flt_boost    50.0        0  # (first order)
• ACL_FILTER_POLES    SSFS_B4_flt_boost    50.0        0.5 #  (second order)
• ACL_FILTER_ZEROS    SSFS_B4_flt_boost    500            0 #
• ACL_FILTER_ZEROS    SSFS_B4_flt_boost    750            0.5 #

Usually Acl translate 2 first order poles or zeros into 1 second order filter, setting the ACL_FILTER_SET last parameter to 1 allows to disable it.

In this case the real poles and zeros can be easaly translated to  first order as

• ACL_FILTER_SET         "SSFS_B4_flt_boost_opt"  2        -7.8        2000    20      1
• ACL_FILTER_POLES    SSFS_B4_flt_boost_opt    50.0        0
• ACL_FILTER_POLES    SSFS_B4_flt_boost_opt    50.0        0.    50.0    0
• ACL_FILTER_ZEROS    SSFS_B4_flt_boost_opt    500         0
• ACL_FILTER_ZEROS    SSFS_B4_flt_boost_opt    750          0    750        0
   

The plots show the output signal and the digital noise level  for a computation running at DSP:

• for the first one using the second order filter without the numerical noise substraction
• for the second one using the first order filter for the low frequency poles and zeros  and  without the numerical noise substraction
• for the last one unsig the first order filter  with the numerical noise substraction enable

We modify the SSFS_Ctrl configuration file in order to have  the SSFS_B4_Err_Q_unnorm_10kHz channel equal to SPRB_B4_56MHz_Q  one.