Giga-tronics 8650B Series, Руководство по эксплуатации

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Series 8650B Universal Power Meters
3-124 Publication 31470-001, Rev C, November 2, 2017
3.19.7 Peak Hold
The Peak Hold feature causes the measured value to hold at the highest instantaneous power measured from
the time the feature is enabled until it is reset (the measured value changes only when it is rising to a new
maximum, or when it is reset).
When the Peak Hold feature is selected, the minimum average power level that can be accurately measured is
-20 dBm. This has been implemented to increase accuracy and maintain wide bandwidth of Peak Hold
measurement over the peak power range of -20 dBm to +20 dBm. The Peak Hold selection will also affect
Histogram measurement if there is power below -20 dBm. To obtain accurate average power measurements
below -20 dBm, the Peak Hold feature should be disabled.
The Peak Hold feature can only be used in the standard measurement collections modes (not in the fast modes),
and only in a modulated measurement mode (MAP, PAP or BAP). Peak Hold is not recommended for use in
combination with the V
PROP
F function.
3.19.7.1 Enabling the Peak Hold Feature
The Peak Hold feature is enabled or disabled by simple commands consisting of one of two function codes:
Syntax: [AE or BE] [PH0 or PH1]
[AE or BE] prefix specifies Sensor A or Sensor B
PH0 disables the Peak Hold function
PH1 enables the Peak Hold function
Example: AE PH1 ! ENABLES THE PEAK HOLD FEATURE FOR SENSOR A
Example 2: BE PH0 ! DISABLES THE PEAK HOLD FEATURE FOR SENSOR B
Description: Like the MN0 and CR0 commands, The PH0 command will disable Crest Factor and Min/Max
measurements. Sending the PH1 command after Peak Hold is enabled will reset it. Peak Hold
will also reset when sending a CR1 command (See Section 3.8).
3.19.7.2 Reading the Peak Hold Value
The Peak Hold value is read over the bus using a simple command:
Syntax: [AE or BE] PKH
[AE or BE] prefix specifies Sensor A or Sensor B
PKH reads the current value stored by the Peak Hold function
Example:
AE PKH ! READS THE PEAK HOLD VALUE FOR SENSOR A
Description: The Peak Hold feature monitors the maximum power as it is measured, but does not provide any
feedback to the controller until a PKH command is received. To monitor for a limit violation, the
Limits feature may be more useful (See Section 3.15).