NAME:
       JDCNV
 PURPOSE:
       Converts Gregorian dates to Julian days   
 CALLING SEQUENCE:
       JDCNV,YR,MN,DAY,HR,JULIAN
 INPUTS:
       YR = Year (integer)  
       MN = Month (integer 1-12)
       DAY = Day  (integer 1-31) 
       HR  = Hours and fractions of hours of universal time (U.T.)
 OUTPUTS:
       JULIAN = Julian date (double precision) 
 CALLED BY:
	CT2LST, Ex2Int [1], Ex2Int [2], UTIME [1], UTIME [2], UT_2_YYDOY [1], ut_2_yydoy [2]
 EXAMPLE:
       To find the Julian Date at 1978 January 1, 0h (U.T.)
       JDCNV,1978,1,1,0.,JULIAN
       will give JULIAN = 2443509.5
 NOTES:
       (1) JDCNV will accept vector arguments 
       (2) JULDATE is an alternate procedure to perform the same function
 REVISON HISTORY:
       Converted to IDL from Don Yeomans Comet Ephemeris Generator,
       B. Pfarr, STX, 6/15/88

	See jitter_subs.pro header for history

NAME:
	jitter_subs
PURPOSE:
	A suite of routines for MDI jitter mode analysis
HISTORY:
 V4.1	20-Jan-95 (MDM) - Various cosmetic changes
			- Broke subroutines into JITTER_SUBS.PRO
			- Allowed sub-menu list to be selected
 V4.2	20-Jan-95 (MDM) - More modifications and adjustments
			- Added MF_SAMPLE structure to the summary
			  structure
			- Backup up 32 samples at missing 1/16th samples
			  (when 239 instead of 240)
 V4.3	23-Jan-95 (MDM) - Made freq peak intensity plot a log plot
 V4.4	27-Jan-95 (MDM) - Made patch to handle incomplete dataset
			  during MK_SUMMARY/SORT_ISS
 V4.5	 2-Feb-95 (MDM) - Patched to handle a mixture of ISS_MODE
			  and image data in a single file.
 V5.0	 6-Feb-95 (MDM) - Modified to pass an assortment of information
			  by replacing "ss_blocks" with a structure
			- Pass and display the input file name
			- Allow background subtraction
 V5.1	 7-Feb-95 (MDM) - Allowed reading/writing summary files on
			  non-SGI machine (byte swapping)
 V5.11	 8-Feb-95 (MDM) - Modified to print bkg subraction info on
			  the PLOT_FFT output
			- Added menu option to change data directory
 V6.00	17-Feb-95 (MDM) - Added Tarbell code to integrate and calculate
			  overall jitter
			- Allowed block selection by clicking on image
			- Allowed masking of spectra by marking bad
			  frequencies
			- Allowed totaling of selected ranges
 V6.01	17-Feb-95 (MDM) - Small changes in plotting format (oplot 0 line)
			- When removing points, remove only the top 3
 V6.10	 1-Mar-95 (MDM) - Various changes and additions
 V6.20  6-Mar-95 (MDM) - Added capability to add title to the plots/displays
 V6.21  6-Mar-95 (MDM) - Allow using previous background for background
			  subtraction
 V6.22	 7-Mar-95 (MDM) - Modification to not count the same frequency twice
			  when integrating to get a total (when marking two
			  regions which overlap)
 V7.00	 6-Feb-96 (MDM) - Modified to work on the flight system
 V7.01	11-Feb-96 (MDM) - Modified to read the raw TFR files
 V7.02	22-Feb-96 (MDM) - Changed all plot reference to "Power" to "Amplitude"
			- Added new option to plot X error,y error amplitude
			- Modified the title creation to be shorter
 V7.03	26-Jun-96 (MDM) - Mod to allow resetting of regions to integrate
			- Added menu option to save spectra to file
 V7.04 27-Jun-96 (MDM) - Corrected derivation of summary saved spectra file name
			- Converted integrated total to arcsec RMS
 V7.05	 9-Jul-96 (MDM) - Corrected to save "summary" variable in summary file
 V7.06 16-Jul-96 (MDM) - Made xmenu_sel the default.  Use "qxwin=0" to use
			  wmenu_sel
			- Made /data14/jitter the default directory
 V7.07	10-Sep-96 (MDM) - Modification to the way that the raw telemetry file is
			  read to fix a new error state
 V7.08	11-Nov-96 (MDM) - Modified DISP_FFT option to mark integrated blocks
			  selected
 V7.09 22-Jan-97 (MDM) - Added OUTDIR option to MK_SUMMARY
			- Added TFR_DIR to main program
 V7.10  4-Sep-97 (RIB) - Possible fix to subscripting problem
			  Updated default start and stop times in .jitter_do
 V7.11	25-Sep-97 (MDM) - Fix ss=ss_block to be a LONG, not string
			  (IDL Ver 5.0 broke this!?!?!)