diff --git a/matlab/@dynDate/dynDate.m b/matlab/@dynDate/dynDate.m
index 7851d2818..9da7d0a27 100644
--- a/matlab/@dynDate/dynDate.m
+++ b/matlab/@dynDate/dynDate.m
@@ -144,31 +144,45 @@ switch nargin
     date = dynDate();
     if isnumeric(b) && isscalar(b) && ismember(b,[1,4,12,52])
         date.freq = b;
-        if ~isnumeric(a)
-            error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be numeric!'])
-        end
-        if ~all(isint(a))
-            error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be a scalar or a 1*2 vector of integers!'])
-        end
-        if ~isequal(size(a),[1,2])
-            if b>1
-                error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be a 1*2 vector of integers.'])
-            end
-        else
-            if isequal(b,1) && isequal(a(2),1)
-                error(['dynDate:: Can''t instantiate the class! The second element of the first input argument ' inputname(a) ' must be equal to one (because freq==1)!'])
-            end
-        end
-        if a(2)<=0 || a(2)>b
-            error(['dynDate:: Can''t instantiate the class! The second element of the first argument ' inputname(a) ' must be a positive integer be <=' int2str(b) '!' ])
-        end
-        if length(a)==1
-            date.time = [a, 1];
-        else
-            date.time = a;
+    elseif ischar(b) && isequal(length(b),1) && ismember(upper(b),{'Y','A','W','M','Q'})
+        b = upper(b);
+        switch b
+          case {'Y','A'}
+            date.freq = 1;
+          case 'W'
+            date.freq = 52;
+          case 'M'
+            date.freq = 12;
+          case 'Q'
+            date.freq = 4;
+          otherwise
+            error(['dynDate:: Can''t instantiate the class! The second argument ' inputname(b) ' must be an integer equal to 1, 4, 12 or 52, or a character equal to ''Y'', ''A'', ''W'', ''M'' or ''Q''!'])
         end
     else
-        error(['dynDate:: Can''t instantiate the class! The second argument ' inputname(b) ' must be equal to 1, 4, 12 or 52.'])
+        error(['dynDate:: Can''t instantiate the class! The second argument ' inputname(b) ' must be an integer equal to 1, 4, 12 or 52, or a character equal to ''Y'', ''A'', ''W'', ''M'' or ''Q''!'])
+    end
+    if ~isnumeric(a)
+        error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be numeric!'])
+    end
+    if ~all(isint(a))
+        error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be a scalar or a 1*2 vector of integers!'])
+    end
+    if ~isequal(size(a),[1,2])
+        if date.freq>1
+            error(['dynDate:: Can''t instantiate the class! The first argument ' inputname(a) ' must be a 1*2 vector of integers.'])
+        end
+    else
+        if isequal(date.freq,1) && isequal(a(2),1)
+            error(['dynDate:: Can''t instantiate the class! The second element of the first input argument ' inputname(a) ' must be equal to one (because freq==1)!'])
+        end
+    end
+    if a(2)<=0 || a(2)>date.freq
+        error(['dynDate:: Can''t instantiate the class! The second element of the first argument ' inputname(a) ' must be a positive integer be <=' int2str(b) '!' ])
+    end
+    if length(a)==1
+        date.time = [a, 1];
+    else
+        date.time = a;
     end
   otherwise
     error('dynDate:: Can''t instantiate the class, wrong calling sequence!')