Download Agilent Technologies E1445A User`s guide

Applications and Example Programs
Synthesizer Switching Speeds
Switch/blanking time is established by the following criteria:
• 350 us for all frequencies 560 MHz or less
• 350 us for all frequencies above 560 MHz with long switch/blanking
mode set (long blanking is typically used when external leveling is
enabled or when using low ALC bandwidth)
• 150 us for all frequencies above 560 MHz with normal
switch/blanking mode set
• 50 us for all frequencies above 560 MHz with power-only mode set
• 20 ms is added, to each of the times listed above, any time the step
attenuator (Option 1E1) is changed
Once switch/blanking time is completed, the settling time begins.
Settling time is user-definable and can be adjusted between a minimum
and maximum value; longer periods of settling time can be specified in
order to gain additional accuracy. Both switch/blanking time and
settling time are used every time a new frequency or power is set up in
the synthesizer. (For more information, refer to “Settling Time” on page
5-23.)
HPE6432_SetLongBlankingState(instrumentHandle,
blankingEnable); is used to indicate whether or not long blanking
time is used during frequency or power changes. This command does
not specify that the RF output be blanked, it only specifies that the
switch/blanking time be set to 350 us.
HPE6432_SetBlankingState(instrumentHandle,
longblankingEnable); is used to turn the blanking on or off for the
RF output during the switch/blanking time.
In summary, there is a delay time that is required by the synthesizer to
change between frequencies or power or both. This delay time is a
combination of the switch/blanking time and settling time. The
switch/blanking time is dependent on the criteria listed above while the
settling time is user-definable and dependent on the accuracy required
of the final signal. If RF blanking is on during switch/blanking time,
you do not see the effects on the RF output, but if RF blanking is off
during switch/blanking time, you see all of the effects on the signal that
might include spurious signals, harmonics, and other glitches. Whether
RF blanking is on or off has no effect on settling time, it only affects the
RF output during switch/blanking time.
Agilent E6432A Microwave Synthesizer User’s Guide
5-21