Technical data

9-8
Understanding the CITIfile Data Format
Useful Calculations
problems with the year 2000, when the shortened version of the year will be "00."
• The hour value should be in 24-hour "military" time.
• When writing a CITIfile and the fractional seconds value is zero, then the "seconds" value may be
printed either with or without a decimal point: either "47.0" or "47" would be acceptable. When reading
a CITIfile, the seconds value should always be read as if it were a floating point number.
Useful Calculations
This section contains information on computing frequency points and expressing CITIfile data in other data
formats.
Computing Frequency Points
In CITIfile, the frequency data is not listed point by point, only the start and stop values are given. If you
are using a spreadsheet program, you can create a new frequency column to the left of the data pairs. Use
the following formula to obtain each frequency point:
Fn = Fstart + {(n-1) * [(Fstop - Fstart) / (# of points - 1)]}
where:
Fstart = Start Frequency
Fstop = Stop Frequency
Fn = Frequency point with n being an integer
# of points = number of sample points per sweep
Here is an example of how this formula may be entered:
F1 = 30E3 + {(1-1) * [(6E9 - 30E3) / (201 - 1)]} = 30E3 = 30 kHz
F2 = 30E3 + {(2-1) * [(6E9 - 30E3) / (201 - 1)]} = 30E6 = 30 MHz
F201 = 30E3 + {(201 - 1) * [(6E9 - 30E3) / (201 - 1)]} = 6E9 = 6 GHz
Once these cells are entered, copy the formula to the remaining data points, and the frequency will be
indicated for each row.
Expressing CITIfile Data in Other Data Formats
CITIfile data is represented in real and imaginary pairs. Equations can be used to express this information
in logarithmic magnitude, phase, polar, and Smith chart formats. Refer to the following table for these
equations.