Language Reference

PWRBW

Example

130

OUTPUT 723;"SNGLS;"

Activate single-sweep mode .

 

140

OUTPUT 723;"CENTERWL 750NM;SP 100NM;

Activate maximum-hold mode . Sweep

 

150

OUTPUT 723;"MXMH TRA;TS;TS;TS;TS;"

trace A four times .

 

160

OUTPUT 723;"PWRBW TRA,99.0?;"

Query bandwidth containing 99%

 

 

 

of the power contained in full span.

 

170

ENTER 723;P

Assign value to computer variable .

Description The PWRBW command ￿rst computes the combined power of all signal responses contained in a trace array, then calculates the bandwidth which

contains a percentage of the total power. For example, if 100% is speci￿ed, the power bandwidth equals the wavelength range of the trace data, which equals the span setting. If 50% is speci￿ed, trace elements are eliminated from each end of the array, until the combined power of the remaining signal responses equals 50% of the total power. The wavelength span of these remaining trace elements is the power bandwidth queried, centered around the center wavelength.

As another example, if PWRBW of 60% is requested, trace points are reduced from both ends until 20% of the power in one end and 20% of the power

in the other end is eliminated. The PWRBW command does not alter the contents of the source trace.

PWRBW must be used as either a query or as a source in another optical spectrum-analyzer command. Form a query by ending the PWRBW statement with a question mark (?). When used as a query, PWRBW gives the bandwidth equal to a percentage of the total power. Use PWRBW as a source by incorporating the PWRBW statement into any optical spectrum-analyzer command containing prede￿ned function in its syntax diagram. When PWRBW is used as a source, the bandwidth value is used for operation by the command that contains PWRBW.

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