pro unh_timing

;Created: Mark Chutter, UNH
;Sep. 13, 2013
;
;Modified:
;Oct.  01, 2013 MWC changed tt2000_offset to long64 to maintain
;                   precision
;Nov. 12, 2013 MWC updated DSP digital delays from Ivan
;Nov. 26, 2013 MWC changed routine name
;Sep.  3, 2014 MWC cleaned up AFG and DFG delay code
;Oct. 23, 2014 MWC new delays from Werner
;Nov. 18, 2014 MWC update for Dec64 from Werner
;Mar. 27, 2015 MWC DAH!!! to avoid repeating a mistake, changing
;                  name of delay_dsp to dsp_correction
;Sep. 28, 2015 MWC updated DFG timing for DEC 64
;
;Description:
;This file defines the offset from TAI 0 to TT2000 and includes
;known most digital and analog delays

common tt2000_offset, tt2000_offset
common delay_afg, delay_afg_128, delay_afg_32, delay_afg_16, delay_afg_8
common delay_dfg, delay_dfg_rate
common dsp_correction, dsp_correction
common hsb_correction, hsb_correction
common delay_edi, delay_edi

;IDL> print, cdf_parse_tt2000('01-Jan-1958 00:00:00.000')
;  -1325419167816000000
;IDL> print, cdf_parse_tt2000('01-Jan-2000 11:58:55.816')
;                     0
;TT = TAI + 32.184 seconds - already taken into account
tt2000_offset = $;in nanoseconds
  cdf_parse_tt2000('01-Jan-1958 00:00:00.000')

;IWF supplied delay for each AFG sample rate, each OBS in seconds
;subtracting gives sample center time
delay_afg_128 = [0.01196, 0.01157, 0.01009, 0.01166]
delay_afg_32 = [0.19946, 0.19907, 0.19759, 0.19916]
delay_afg_16 = [0.44946, 0.44907, 0.44759, 0.44916]
delay_afg_8 = [0.94946, 0.94907, 0.94759, 0.94916]

;IWF supplied delay for each DFG sample rate in seconds
;[128/s, 32/s, 16/s, 8/s] for DEC 32, DEC64 is additional 7.81 ms
;subtracting gives sample center time
delay_dfg_rate = [0.00834, 0.19584, 0.44584, 0.94584]

;Add the CDPU's 24 microseconds to DSP values.
;from 108328revE_MMS_DSP_CEB_ICD.pdf
;DSP frequency dependent filter delays for 16kss channels
;"The delay must be subtracted from the packet time-stamp"
dsp_correction = dblarr(15)
dsp_correction[0] = -0.000183d
dsp_correction[1] = -0.000611d
dsp_correction[2] = -0.001527d
dsp_correction[3] = -0.003358d
dsp_correction[4] = -0.00702d
dsp_correction[5] = -0.01435d
dsp_correction[6] = -0.02900d ;256 samples/s
dsp_correction[7] = -0.05833d ;128 samples/s
dsp_correction[8] = -0.1169d
dsp_correction[9] = -0.2341d
dsp_correction[10] = -0.4689d
dsp_correction[11] = -0.9376d
dsp_correction[12] = -1.877d
dsp_correction[13] = -3.748d
dsp_correction[14] = -7.495d

;filter delay + PPS delay + sample/hold delay + analog
dsp_correction = dsp_correction + 0.0000237d - 0.0000033d - 0.0000606d

;DSP frequency dependent filter delays for 256kss channels
hsb_correction = dblarr(6)
hsb_correction[0] = -0.00001144d
hsb_correction[1] = -0.00003814d
hsb_correction[2] = -0.00009537d ;65536 samples/s
hsb_correction[3] = -0.0002060d
hsb_correction[4] = -0.0004272d
hsb_correction[5] = -0.0009308d

;filter delay + PPS delay + sample/hold delay; no  analog for HSB
hsb_correction = hsb_correction + 0.0000237d - 0.0000033d

delay_edi = 0.0000237d

end