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5-18 CALCulate1 Subsystem
The following string is a typical example of the first few
returned values:
+4.02646500E+001,+6.78125100E+001,+6.17986600E+001,+4.26768200E
+001,+4.80245300E+001,+3.10491300E+001,+1.13409400E+001,+5.07832
500E+001,+2.77746200E+001,+3.89150500E+001,+3.50217600E+001,+7.3
4649800E-001,+5.64983800E+000,
Notice that only measurement values are returned to
the computer. There is no first value that indicates the
number of values contained in the string as there is, for
example, with the FETCh, READ, and MEASure com-
mands. Use the :CALCulate1:TRANsform:FRE-
Quency:POINTs command to query the number of
points the :CALC1:DATA? returns.
When NORMAL measurement mode is selected, the
uncorrected frequency domain data consists of 64K val-
ues. Only the frequency domain data corresponding to
1270–1650 nm wavelength (in vacuum) is returned
(15,047 values). In FAST measurement mode, the data
consists of 32K values of which 7,525 values are
returned.
In NORMAL measurement mode, the frequency spacing
between values is uniform and is equal to 3.613378
GHz. Note that the spacing between values is not uni-
form in wavelength units. The values returned are in
ascending optical frequency.
The first value of the uncorrected frequency data corre-
sponds to an optical frequency of 181.6915 THz
(1650.008 nm). The last value of the uncorrected fre-
quency data corresponds to an optical frequency of
236.0584 THz (1269.993 nm). For example, a laser line
peak located at the 3,000th returned value has an opti-
cal frequency of:
,
(
)
=
+
frequency
181.6915 THz
2 999 3.613378 GHz
=
192.5280 THz
or, 1557.137 nm (in vacuum).
When FAST measurement mode is selected, the fre-
quency spacing between elements is uniform and is
equal to 7.226756 GHz. Note the spacing between val-
ues is not uniform in wavelength units. The values
returned are in ascending optical frequency. Only the
frequency domain data corresponding to 1270–1650 nm
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