function varargout=tach(varargin)

 [hr]=tach(recordName,annotator,N,N0,ouputSize)

    Wrapper to WFDB TACH:
         http://www.physionet.org/physiotools/wag/tach-1.htm

    Reads a WFDB record and Annotation file to return:


 hr     
       Nx1 vector of doubles representing a uniformly sampled and
       smoothed instantaneous heart rate signal. The output are samples 
       of the instantaneous heart rate signal in units of beats per minute.

 Required Parameters:

 recorName
       String specifying the name of the record in the WFDB path or
       in the current directory.

 annotator  -
       String specifying the name of the annotation file in the WFDB path or
       in the current directory.

 Optional Parameters are:

 N 
       A 1x1 integer specifying the sample number at which to stop reading the 
       annotation file (default read all = N).
 N0 
       A 1x1 integer specifying the sample number at which to start reading the 
       annotation file (default 1 = begining of the record).

 outputSize

    A 1x1 integer specifying the number of output samples (ie estimated
    heart rate intervals) such that the output 'hr' is a vector of 
    size (outputSize-1) x 1.


 Written by Ikaro Silva, 2013
 Last Modified: January 24, 2014
 Version 1.1

 Since 0.0.1

 %Example 1- Read a signal and annotaion from PhysioNet's Remote server:
[hr]=tach('challenge/2013/set-a/a01','fqrs'); 
plot(hr);grid on;hold on