Keysight E4428C ESG RF Programming Manual page 209

Data Questionable Frequency Event Enable Register
Lets you choose which bits in the Data Questionable Frequency Event Register set the summary bit
(bit 5 of the Data Questionable Condition Register) to 1.
Command:
STATus:QUEStionable:FREQuency:ENABle <value>, where <value> is the sum of the decimal values
of the bits you want to enable.
Example: Enable bit 4 and bit 3 so that whenever either of those bits are set to 1, the Data Questionable
Frequency summary bit of the Data Questionable Condition Register is set to 1. Send the command
STAT:QUES:FREQ:ENAB 520 (16 + 8).
Query: STATus:QUEStionable:FREQuency:ENABle?
Response: Decimal value of the sum of the bits previously enabled with the
STATus:QUEStionable:FREQuency:ENABle <value> command.
Keysight Signal Generators Programming Guide
Programming the Status Register System
Status Groups
201