function WUPSMPLE, x
;+
; NAME:
; 	 WUPSMPLE
;
; PURPOSE:
;	This function performs an upsampling operation.
;
; CATEGORY:
;	Wavelets
;
; CALLING SEQUENCE:
;    y = WUPSMPLE(x) 
;
; INPUTS:
;    x:   1-d signal, of length n
;
; OUTPUTS:
;   y:   1-d signal, of length 2*n with zeros
;       interpolating alternate samples
;       y(2*i-2) = x(i-1), i=1 ..n
;
; EXAMPLE:
;
; SEE  ALSO:
;	wdndydhi, wdndydlo, wupdydhi, wiwtpo, waconv
;
; MODIFICATION HISTORY:
; 	Written by:	Amara Graps		November, 1994
;Translated from MatLab Wavelab routine: upsample.m
;-

n = N_ELEMENTS(x)*2
y = FLTARR(n)

;use the IDL way to create an index array
a = 1 & b = 2 & c = n-1
indx_arr = WMKIARRY( a, b, c) 

y(indx_arr)=x

;
; Algorithm Source:  WaveLab Version 0.600
; WaveLab WWW site: http://playfair.stanford.edu/ 
; WaveLab Questions? e-mail wavelab@playfair.stanford.edu
;   
    

RETURN, y 
END 
;***************************************************