prog.book : chapter1.fm 68 Mon Feb 15 09:24:37 1999
Power Meter Remote Operation
Getting the Best Speed Performance
1-68
HP E4418B/E4419B Programming Guide
For example, with a filter length of 4 and
SENS:SPE
set to
20
,
approximately 5 readings/sec will be calculated by the power meter.
In general, free run mode will provide the best speed performance from
the power meter (especially in 200 readings/sec mode).
Output Format
The power meter has two output formats for measurement results:
ASCii
and
REAL
. These formats can be selected using the
FORMat
command.
When
FORMat
is set to
REAL
, the result returned is in IEEE 754
floating-point format (note that the byte order can be changed using
FORMat:BORDer
).
The
REAL
format is likely to be required only for 200 readings/sec mode as
a means to reduce bus traffic.
Units
The power meter can output results in either linear or log units. The
internal units are linear and therefore optimal performance will be
acheived when the results output are also in linear units (since the
overhead of performing a log function is removed).
Command Used
In free run trigger mode,
FETC?
must be used to retrieve a result.
In other trigger modes, there are a number of commands which can be
used, for example,
MEAS?, READ?, FETC?
Note that the
MEAS?
and
READ?
commands are compound commands i.e., they perform a
combination of other lower level commands. In general, the best speed
performance will be achieved using the low level commands directly.
200 Readings/Sec
In the highest speed setting, the limiting factor tends to be the speed of
the controller being used to retrieve results from the power meter and to a
certain extent the volume of HP-IB traffic. The latter can be reduced using
the
FORMat REAL
command to return results in binary format. The
former is a combination of two factors:
Summary of Contents for E4418B
Page 25: ...prog book chapter1 fm 1 Mon Feb 15 09 24 37 1999 1 Power Meter Remote Operation ...
Page 138: ...prog book ch2meas fm 1 Mon Feb 15 09 24 37 1999 2 MEASurement Instructions ...
Page 200: ...prog book ch3calc fm 1 Mon Feb 15 09 24 37 1999 3 CALCulate Subsystem ...
Page 228: ...prog book ch4cal fm 1 Mon Feb 15 09 24 37 1999 4 CALibration Subsystem ...
Page 242: ...prog book ch5disp fm 1 Mon Feb 15 09 24 37 1999 5 DISPlay Subsystem ...
Page 260: ...prog book ch6form fm 1 Mon Feb 15 09 24 37 1999 6 FORMat Subsystem ...
Page 264: ...prog book ch7mem fm 1 Mon Feb 15 09 24 37 1999 7 MEMory Subsystem ...
Page 294: ...prog book ch8out fm 1 Mon Feb 15 09 24 37 1999 8 OUTput Subsystem ...
Page 302: ...prog book ch9sens fm 1 Mon Feb 15 09 24 37 1999 9 SENSe Subsystem ...
Page 360: ...prog book ch10stat fm 1 Mon Feb 15 09 24 37 1999 10 STATus Subsystem ...
Page 384: ...prog book ch11syst fm 1 Mon Feb 15 09 24 37 1999 11 SYSTem Subsystem ...
Page 420: ...prog book ch12trig fm 1 Mon Feb 15 09 24 37 1999 12 TRIGger Subsystem ...
Page 434: ...prog book ch13unit fm 1 Mon Feb 15 09 24 37 1999 13 UNIT Subsystem ...
Page 442: ...prog book ch14serv fm 1 Mon Feb 15 09 24 37 1999 14 SERVice Subsystem ...
Page 452: ...prog book ch15ieee fm 1 Mon Feb 15 09 24 37 1999 15 IEEE488 2 Command Reference ...
Page 481: ...prog book progIX doc 6 Mon Feb 15 09 24 37 1999 Index 6 HP E4418B E4419B Programming Guide ...