function tykw_gt_mfreq,rdata

;+
; NAME:
;       TYKW_GT_MFREQ
;
; PURPOSE:
;       This procedure is getting the frequency information  from the
;       TYKW raw data
;
; CALLING SEQUENCE:
;       mfreq=tykw_gt_mfreq(rdata)
;
; INPUTS:
;       rdata: structure of the raw data
;
; OPTIONAL INPUT KEYWORDS:
;
; OUTPUTS:
;       mfreq: frequency ID (0: 9GHz, 1: 4GHz, 2: 2GHz, 3: 1GHz)
;
; HISTORY:
;    4/6/79        ver.0.0 K. Shibasaki as fortran program
;    Sep. 09, 1994 ver.1.0 M. Nishio
;    Jan. 10, 1995 ver.2.0 M. Nishio
;    Apr. 13, 1995 ver.3.2 M. Nishio
;    Apr. 13, 1995 ver.4.0 M. Nishio
;    May. 23, 1995 ver.5.0 M. Nishio
;    May  01, 1995 ver.5.2 M. Nishio
;    Apr. 25, 1995 ver.5.0 M. Nishio
;
;    1999-01-12 ported to IDL by TY
;
;-

case rdata(0).channel of
  10 : mfreq=0 ; 9 GHz I
  11 : mfreq=0 ; 9 GHz V
  12 : mfreq=1 ; 4 GHz I
  13 : mfreq=1 ; 4 GHz V
  14 : mfreq=2 ; 2 GHz I
  15 : mfreq=2 ; 2 GHz V
  16 : mfreq=3 ; 1 GHz I
  17 : mfreq=3 ; 1 GHz V
endcase

return,mfreq
end