Keysight Technologies 86120B, User Manual

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158
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 frequency
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:FREQuency:POINts command or
the resolution argument of an instrument function.
Refer to “Measurement Instruc-
tions” on page 146 .
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:
+4.02001,+6.78001,+6.17001,+4.26001,+4.802453
00E+001,+3.10001,+1.13001,+5.07001,+2.77001,
+3.89001,+3.50001,+7.34649800E-001,+5.64000,
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 :CALCu-
late1: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 correspond-
ing 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.