function [p, initialcross, finalcross, nextcross, midreference]= pulseperiod(x, varargin)
// This function estimate pulse period of real vector X.
// Calling Sequence
// p=pulseperiod(x)
// p=pulseperiod(x, Fs)
// p=pulseperiod(x, t)
// p=pulseperiod (x, t, 'Polarity', pol)
// p=pulseperiod(x, t, 'MidPercentReferenceLevel', N )
// p=pulseperiod(x, t, 'Tolerance', M)
// p=pulseperiod(x, t,'StateLevels', O)
// [p initialcross finalcross nextcross midreference]=pulseperiod(x)
// [p initialcross finalcross nextcross midreference]=pulseperiod(x, t)
// [p initialcross finalcross nextcross midreference]=pulseperiod(x, t)
// [p initialcross finalcross nextcross midreference]=pulseperiod(x, t, 'Polarity', pol)
// [p initialcross finalcross nextcross midreference]=pulseperiod(x, t, 'MidPercentReferenceLevel', N )
// [p initialcross finalcross nextcross midreference]= pulseperiod(x, t, 'Tolerance', M)
// [p initialcross finalcross nextcross midreference]= pulseperiod(x, t,'StateLevels', O)
// [p initialcross finalcross nextcross midreference]= pulseperiod(x, t,'StateLevels', O, 'fig', 'on' or 'off')
//
// Parameters
// x: real vector.
// Fs: specifies the sample rate, Fs, as a positive scalar, where the first sample instant corresponds to a time of zero.
// t: defiene instant sample time t as vector with same length of x, or specifies the sample rate, t, as a positive scalar.
// Polarity: specify the polarity of the pulse as either 'positive' or 'negative', where the default value is 'positive'
// MidPercentReferenceLevel: specify the mid percent reference leves as a percentage, default value of N is 50.
// Tolerance: define the tolerance value as real scaler value, where default value of M is 2.0.
// StateLevels: define the lower and upper state levels as two element real vector.
// fig: specify the logical input value to display figure as one of 'on' or 'off', where the default input in 'off'.
// p: returns a vector of difference between the mid-crossings of the initial transition of each positive-polarity pulse and the next positive-going transition
// initialcross: returns a vector of initial cross values of bilevel waveform transitions X
// finalcross: returns a vector of final cross values of bilevel waveform transitions X
// nextcross: returns a vector of next cross values of bilevel waveform transitions X
// midreference: return mid reference value corrosponding to mid percent reference value.
// Examples
//x = fscanfMat("macros/pulsedata_x.txt");
//t = fscanfMat("macros/pulsedata_t.txt");
//clf
//p = pulseperiod(x,t,'fig','ON')
//Output
// p =
//
// 0.5002996
//also it generates a pulse plot with pulse period
// See also
// Authors
// Jitendra Singh
// run statelevels and midcross function before running risetime function.
if or(type(x)==10) then
error ('Input arguments must be double.')
end
if length(varargin)==0 then
varargin=varargin;
end
sindex=[];
if length(varargin)>=1 then
a=1;
for i=1:length(varargin)
if type(varargin(i))==10 then
sindex(a)=i;
a=a+1;
end
end
end
pol='POSITIVE';
polidx=[];
fig='OFF'
index_on=[];
if (~isempty(sindex)) then
for j=1:length(sindex)
select convstr(varargin(sindex(j)), 'u') // validating input variable names
case {'STATELEVELS'}
if length(varargin) <=sindex(j) then
error(strcat(['parameter StateLevels required a value']));
end
if type(varargin(sindex(j)+1))==1 then
levels=varargin(sindex(j)+1);
elseif type(varargin(sindex(j)+1))==10 & convstr(varargin(sindex(j)+1), 'u')=='MIDPERCENTREFERENCELEVEL' | convstr(varargin(sindex(j)+1),'u')== 'TOLERANCE' | convstr(varargin(sindex(j)+1), 'u')=='FIG' | convstr(varargin(sindex(j)+1), 'u')=='POLARITY' then
error('parameter StateLevels required a value.')
elseif type(varargin(sindex(j)+1))==10 then
error('Expected STATELEVELS to be one of these types: double, Instead its type was char.')
end
case {'MIDPERCENTREFERENCELEVEL'}
if length(varargin) <=sindex(j) then
error(strcat(['parameter MidPercentRefernceLevel required a value.']));
end
if type(varargin(sindex(j)+1))==1 then
midpercentval= varargin(sindex(j)+1);
elseif type(varargin(sindex(j)+1))==10 & convstr(varargin(sindex(j)+1), 'u')=='STATELEVELS' | convstr(varargin(sindex(j)+1),'u')== 'TOLERANCE' | convstr(varargin(sindex(j)+1), 'u')=='FIG' | convstr(varargin(sindex(j)+1), 'u')=='POLARITY' then
error('parameter MidPercentRefernceLevel required a value.')
elseif type(varargin(sindex(j)+1))==10 then
error('Expected MidPercentRefernceLevel to be one of these types: double, Instead its type was char.')
end
case {'TOLERANCE'}
if length(varargin) <=sindex(j) then
error(strcat(["parameter Tolerance required a value"]));
elseif type(varargin(sindex(j)+1))==1 then
tolerance= varargin(sindex(j)+1);
elseif type(varargin(sindex(j)+1))==10 & convstr(varargin(sindex(j)+1), 'u')== 'STATELEVELS' | convstr(varargin(sindex(j)+1), 'u')== 'MIDPERCENTREFERENCELEVEL' | convstr(varargin(sindex(j)+1), 'u')=='FIG' | convstr(varargin(sindex(j)+1), 'u')=='POLARITY' then
error('parameter Tolerance required a value.');
elseif type(varargin(sindex(j)+1))==10 then
error('Expected Tolerance to be one of these types: double, Instead its type was char.');
end
case {'FIG'}
if length(varargin) <=sindex(j) then
error(strcat(['parameter fig required a value.']));
end
if type(varargin(sindex(j)+1))==1 then
error ('Expected fig to match one of these strings: on or off');
elseif type(varargin(sindex(j)+1))==10 & convstr(varargin(sindex(j)+1), 'u')=='STATELEVELS' | convstr(varargin(sindex(j)+1), 'u')== 'TOLERANCE' | convstr(varargin(sindex(j)+1), 'u')=='MIDPERCENTREFERENCELEVEL' | convstr(varargin(sindex(j)+1), 'u')=='POLARITY' then
error('parameter fig required a value.')
else
fig= convstr(varargin(sindex(j)+1), 'u');
end
if fig == 'OFF' | fig == 'ON' then
else
error('Expected fig to match one of these strings: on or off');
end
case{'ON'}
index_on=sindex(j)
if length(varargin) == 1 then
error ('Unexpected input.')
elseif type(varargin(sindex(j)-1))==1 then
error ('Unexpected input.');
elseif convstr(varargin(sindex(j)-1), 'u')~='FIG' then
error('Unexpected input');
end
case{'OFF'}
if length(varargin) == 1 then
error ('Unexpected input.')
elseif type(varargin(sindex(j)-1))==1 then
error ('Unexpected input.');
elseif convstr(varargin(sindex(j)-1), 'u')~='FIG' then
error('Unexpected input');
end
case{'POLARITY'}
if length(varargin)<=sindex(j) then
error ('Parameter polarity requires a value.')
end
if type( varargin(sindex(j)+1))==1 then
error ('POLARITY must be either ''Positive'' or ''Negative''.')
elseif type(varargin(sindex(j)+1))==10 & convstr(varargin(sindex(j)+1), 'u')== 'STATELEVELS' | convstr(varargin(sindex(j)+1), 'u')== 'MIDPERCENTREFERENCELEVEL' | convstr(varargin(sindex(j)+1), 'u')== 'TOLERANCE' | convstr(varargin(sindex(j)+1), 'u')=='FIG' then
error ('Parameter polarity requires a value.')
elseif convstr(varargin(sindex(j)+1), 'u') ~= 'POSITIVE' & convstr(varargin(sindex(j)+1), 'u')~= 'NEGATIVE' then
error ('POLARITY must be either ''Positive'' or ''Negative''.');
else
polidx=sindex(j);
end
case {'POSITIVE'}
if j==1 then
error(strcat(['Unexpected option:', " ", varargin(sindex(j))]));
elseif convstr(varargin(sindex(j)-1), 'u') ~= 'POLARITY'
error(strcat(['Unexpected option:', " ", varargin(sindex(j))]));
else
polinputidx= sindex(j);
pol= convstr(varargin (sindex(j)), 'u') ;
end
case {'NEGATIVE'}
if j==1 then
error(strcat(['Unexpected option:', " ", varargin(sindex(j))]));
elseif convstr(varargin(sindex(j)-1), 'u') ~= 'POLARITY'
error(strcat(['Unexpected option:', " ", varargin(sindex(j))]));
else
polinputidx= sindex(j);
pol= convstr(varargin (sindex(j)), 'u') ;
end
else
error(strcat(['Invalid optional argument'," ", varargin(sindex(j))]));
end // switch
end // for
end // if
//
if length(index_on)>0 then
varargin(index_on)='OFF';
end
if length(polidx)>0 then
varargin(polidx)=null();
varargin(polinputidx-1)=null();
end
[crossval midref levels t tolerance]= midcross(x, varargin(:));
upperbound= levels(2)- (tolerance/100)*(levels(2)-levels(1));
mostupperbound=levels(2)+ (tolerance/100)*(levels(2)-levels(1));
lowerbound= levels(1)+ (tolerance/100)*(levels(2)-levels(1));
mostlowerbound=levels(1)- (tolerance/100)*(levels(2)-levels(1));
int_pos=[];
final_pos=[];
int_neg=[];
final_neg=[];
nextcross_pos=[];
nextcross_neg=[];
if length(crossval)>=2 then
if x(1)>midref then
int_pos=crossval(2:2:$);
final_pos=crossval(3:2:$);
int_neg=crossval(1:2:$);
final_neg=crossval(2:2:$);
else
int_pos=crossval(1:2:$);
final_pos=crossval(2:2:$);
int_neg=crossval(2:2:$);
final_neg-crossval(3:2:$);
end
if length(int_pos)>=2 then
nextcross_pos=int_pos(2:$);
end
if length(int_neg)>=2 then
nextcross_neg=int_neg(2:$);
end
if length(int_pos)>length(final_pos) then
int_pos=int_pos(1:($-1))
elseif length(int_neg)>length(final_neg) then
int_neg=int_neg(1:($-1))
end
if length(int_pos)>length(nextcross_pos) then
int_pos=int_pos(1:($-1))
end
if length(final_pos)>length(nextcross_pos)
final_pos=final_pos(1:($-1))
end
if length(int_neg)>length(nextcross_neg) then
int_neg=int_neg(1:($-1));
end
if length(final_neg)>length(nextcross_neg) then
final_neg=final_neg(1:($-1));
end
end
p=[];
if pol=='POSITIVE' then // checking the input variable polarity
p= nextcross_pos-int_pos;
initialcross=int_pos;
finalcross=final_pos;
nextcross=nextcross_pos;
else
p= nextcross_neg-int_neg;
initialcross=int_neg;
finalcross=final_neg;
nextcross=nextcross_neg;
end
midreference=midref; // return midreference value
if fig=='ON' then // if the defined output is only 1, the it will provide the graphical representation of //levels
if length(p)==0 then
plot(t,x, 'LineWidth',1, 'color', 'black')
// xtitle('', 'Time (second)','Level (Volts)' );
plot(t,midreference * ones(1, length(t)),'-r', 'LineWidth',0.5)
plot(t,mostupperbound * ones(1, length(t)),'--r', 'LineWidth',0.5)
plot(t,levels(2) * ones(1, length(t)),'--k', 'LineWidth',0.5)
plot(t,upperbound * ones(1, length(t)),'--r', 'LineWidth',0.5)
plot(t,lowerbound *ones(1, length(t)),'--g', 'LineWidth',0.5)
plot(t,levels(1) * ones(1, length(t)),'--k', 'LineWidth',0.5)
plot(t,mostlowerbound * ones(1, length(t)),'--g', 'LineWidth',0.5)
xlabel("Time (second)", "fontsize",3, "color", "black" )
ylabel("Level (Volts)", "fontsize",3, "color", "black" )
legends(["Signal"; "upper boundary"; "upper state"; "lower boundary"; "mid reference"; "upper boundary"; "lower state"; "lower boundary"], [[1;1], [5;2], [1;2], [5;2], [5;1], [3;2], [1;2], [3;2]], opt='?')
else
plot(t,x, 'LineWidth',1, 'color', 'black')
plot(t,midreference * ones(1, length(t)),'-g', 'LineWidth',0.5)
//n=length(finalcross);
rects=[initialcross(1:2:$); levels(2)*ones(p(1:2:$)); p(1:2:$); (levels(2)-levels(1))*ones(p(1:2:$))]
col=-10*ones(p(1:2:$));
midc=[nextcross, initialcross, finalcross];
midcross=gsort(midc, 'c','i' )
plot(midcross, midreference*ones(midcross), "r*", 'MarkerSize',15);
plot(t,mostupperbound * ones(1, length(t)),'--r', 'LineWidth',0.5)
plot(t,levels(2) * ones(1, length(t)),'--k', 'LineWidth',0.5)
plot(t,upperbound * ones(1, length(t)),'--r', 'LineWidth',0.5)
plot(t,midreference * ones(1, length(t)),'-r', 'LineWidth',0.5)
plot(t,lowerbound *ones(1, length(t)),'--g', 'LineWidth',0.5)
plot(t,levels(1) * ones(1, length(t)),'--k', 'LineWidth',0.5)
plot(t,mostlowerbound * ones(1, length(t)),'--g', 'LineWidth',0.5)
xrects(rects, col);
xlabel("Time (second)", "fontsize",3, "color", "black" )
ylabel("Level (Volts)", "fontsize",3, "color", "black" )
legends(["pulse period"; "Signal"; "mid cross"; "upper boundary"; "upper state"; "lower boundary"; "mid reference"; "upper boundary"; "lower state"; "lower boundary"], [[-11; 2] , [1;1], [-10;5], [5;2], [1;2], [5;2], [5;1], [3;2],[1;2], [3;2]],1)
end
end
//
//
endfunction