58
Keysight M8132A 640 GSa/s Digital Signal Processor User’s Guide
6
Remote Programming
Latency Calibration Commands
The Latency Calibration commands are used to initialize the deterministic
latency in the data path between the M8131A digitizer and the DSP. The
digitizer, as the module connected upstream in the data path, will be
referred to as the master in the command description. The DSP, as the
module connected downstream in the data path, will be referred to as the
slave. For deterministic latency initialization, a defined sequence of
commands must be sent to master and slave. For more information, refer
to the example program described in section “Continuous Streaming with
Constant Latency to DSP Module” in the M8131A user guide.
:CALibrate:LATency:LCMPeriod
Command
:CALibrate:LATency:LCMPeriod <lcm_period>
Description
This command sets the Least Common Multiple (LCM) period value to be
used for core clock phase alignment. On the master module, this value
determines the frequency of the signal sent out at the Sync Out. On the
slave module, this value determines the frequency of the signal used to
compare with the signal received at the Sync In. The formula for the
frequency is:
f = 400MHz / LCM period.
<lcm_period> The LCM period as an even integer between 2 and 32768.
Query
:CALibrate:LATency:LCMPeriod?
Description
This query returns the current LCM period.
:CALibrate:LATency:MODE
Command
:CALibrate:LATency:MODE {SEParate | COMBined}
Description
This command selects the latency calibration mode.
• SEParate – Phase alignment to the master’s core clock and latency
calibration are separate steps. This mode is used for latency setup
between M8131A and M8132A DSP.
• COMBined - Phase alignment to the master’s core clock and latency
calibration is done in the same step. This mode is used for the latency
setup between M8131A and M8121A AWG.
