function [activef]=activeVDSLf(f,afset,hamPSD)
%% ===========================================================================
% activeVDSLf - Generates a vector with active frequencies from
%               a set of start and stop frequencies
%
% Parameter:    f	Frequency axis
% Parameter:    afset	Active frequencies, start and stop points
% Parameter:    hamPSD	PSD for HAM bands
%
% Returns:      activef The active frequencies
%
% Examples:
%  f=1e3:1e3:12e6;
%  act=activeVDSLf(f,[138 2875 5225 6925]*1e3); % Direct use
%  plot(f,act)
%
%  % As part of a callback    
%  tfplan.PSD.active.actmaskds = ...
%    sprintf('activeVDSLf(f,[%s])',num2str([138 2875 5225 6925]*1e3));
%    
%% ===========================================================================

%% ===========================================================================
% Copyright (C) 2003-2009 by Forschungszentrum Telekommunikation Wien, Austria;
%                                                     All rights reserved. 
% Project       : FTW's xDSLsimu
% Author(s)     : Tomas Nordstrom (Tomas.Nordstrom@FTW.at)
%
% CVS:       $Id: activeVDSLf.m,v 1.3 2005/01/04 10:32:28 tono Exp $
%% ===========================================================================
% Change History
%      2003-12-01 (ToNo) Created to help etsi_tfplansVDSL
%% ===========================================================================

if nargin>2,
    HAM=1;
else
    HAM=0;
end
 
if mod(length(afset),2) == 1
    error('activeVDSLf: Not an even number for start and stop frequencies');
end;

activef = zeros(size(f));
for bandp = 1:2:length(afset);
    fix=find(f>=afset(bandp) & f<=afset(bandp+1));
    activef(fix)=1;
    if HAM
        fixham = hamPSD<10^-6;            % HAM band
        activef(fixham)=0;
    end;
end;