diff --git a/crpptbx/AUG/aug_help_parameters.m b/crpptbx/AUG/aug_help_parameters.m
index 6fae2053ce8e0ff79a220abff60b118b3c370092..dde25b8d29b6ed5273c2a8a1ec86c4fbf44147bd 100644
--- a/crpptbx/AUG/aug_help_parameters.m
+++ b/crpptbx/AUG/aug_help_parameters.m
@@ -28,6 +28,7 @@ help_struct_all = struct(...
 % $$$                     char(10) 'cxrs: (time_interval can have several nbs) take data and average over time interval(s) only, plots from CXRS_get_profiles are then provided' ...
 % $$$                     ' as well'];
 help_struct_all.extra_arg_sf2sig = 'extra parameters given to sf2sig type of calls, should be effective full args in one string like extra_arg_sf2sig= ''''''-ed'''',2''';
+help_struct_all.special_signal = 'specific parameter,area-base,param-set,time-base signal, can be provided as 4th signal in data_request if explicit. Example: ''special_signal'',''param:gyro_freq''';
 help_struct_all.fit_tension = ['smoothing value used in interpos fitting routine, -30 means ''30 times default value'', thus -1 often a' ...
                     ' good value' char(10) ...
 		    'cxrs, nete: if numeric, default for all cases, if structure, default for non given fields'];
diff --git a/crpptbx/AUG/gdat_aug.m b/crpptbx/AUG/gdat_aug.m
index d3b9ec7b14e4874dad559fc822b22dabd6eff1ff..a08ab492d76fb2669084d0d316511310bf544d58 100644
--- a/crpptbx/AUG/gdat_aug.m
+++ b/crpptbx/AUG/gdat_aug.m
@@ -230,10 +230,14 @@ end
 extra_arg_sf2sig = '[]';
 if isfield(gdat_params,'extra_arg_sf2sig') && ~isempty(gdat_params.extra_arg_sf2sig)
   extra_arg_sf2sig = gdat_params.extra_arg_sf2sig;
-else
-  gdat_params.extra_arg_sf2sig = extra_arg_sf2sig;
 end
 gdat_params.extra_arg_sf2sig = extra_arg_sf2sig;
+%
+special_signal = '';
+if isfield(gdat_params,'special_signal') && ~isempty(gdat_params.special_signal)
+  special_signal = gdat_params.special_signal;
+end
+gdat_params.special_signal = special_signal;
 
 % if it is a request_keyword can obtain description:
 if ischar(data_request_eff) || length(data_request_eff)==1