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5-27
Programming Commands
CALCulate1 Subsystem
DATA?
Queries
uncorrected
frequency-spectrum data of the input laser line.
Syntax
:CALCulate1:DATA?
Attribute
Summary
Preset
State: not affected
SCPI Compliance: standard
Query Only
Description
The returned values are in squared Watts (linear) units. No amplitude or fre-
quency correction is applied to the values. To obtain the logarithmic (dB)
result, normalize the returned values by the largest value, then take five times
the logarithm of the returned values.
Be prepared to process a large amount of data when this query is sent. The
amount of data returned depends on the measurement update state of the
instrument which can be set using the :CALCulate1:TRANsform:FRE-
Quency:POINts command or the resolution argument of an instrument func-
tion. Refer to “Measurement Instructions” on page 5-15.
When
NORMAL
measurement update is specified, over 580 kilobytes of data
(34,123 values) can be returned to the computer. When
FAST
measurement
update is specified, over 72 kilobytes of data (4,268 values) can be returned.
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,+3.1
0491300E+001,+1.13409400E+001,+5.07832500E+001,+2.77746200E+001,+3.89150500E+001,+3.50217
600E+001,+7.34649800E-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 commands. Use
the :CALCulate1:TRANsform:FREQuency: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 (65,536) values. Only the frequency domain data
corresponding to 700-1650 nm wavelength (in vacuum) is returned (34,123
values). In
FAST
measurement mode, the data consists of 8K (8,192) values of
which 4,268 values are returned.