Channel{1|2|3|4}:Srate - Keysight 8990B Programming Manual

CHANnel{1|2|3|4}:SRATe?

This query returns the sampling rate for the specified channel.
Syntax
Example
CHAN1:SRAT?
Remark
The sampling rate is the same for a channel pair (1 and 4 or 2 and 3).
Keysight 8990B Programming Guide
CHAN
1
2
3
4
?
:SRAT
Queries the channel 1 sampling rate.
CHANnel Subsystem 6
185