Use Usb Or Lan Connection Instead Of Gpib; Minimize Dut/Instrument Setup Changes; Avoid Unnecessary Use Of *Rst; Avoid Automatic Attenuator Setting - Keysight N9000A Manual

SCPI Programming Fundamentals
Techniques for Improving Measurement Performance
• When doing bottom/middle/top measurements on Base Stations, you can reduce transactions by making a time slot
active at each of the B,M,T frequencies. Then, issue three measurements at once in the programming code and
retrieve three data sets with just one bus transaction pair (write, read).
For example, send READ:PFER? <Freq_bottom>; PFER? <Freq_middle>; PFER? <Freq_top>. This single
transaction initiates three different phase and frequency error measurements at each of the three different frequencies
provided and returns three sets of data.

Use USB or LAN Connection instead of GPIB

USB and LAN networks allow faster data input and output, relative to GPIB. This is especially important if you are moving
large blocks of data.
Note that LAN transfer speeds are affected by the volume of LAN traffic, and may be degraded if, for example, the
instrument is connected to a busy enterprise LAN. Thus you may want to use a private LAN that is dedicated for the test
system.

Minimize DUT/instrument Setup changes

• Some instrument setup parameters are common to multiple measurements, making it possible to organize the test
process in such a way as to minimize setup changes. If the process involves nested loops, make sure that the
innermost loop is the fastest. Also, check whether the loops could be nested in a different order to reduce the number
of parameter changes as you step through the test.
• If you must switch between measurements, remember that if you have already set your Meas Setup parameters for a
measurement, and you want to make another one of these measurements later, you should use the query
READ:<meas>?.
The MEASure:<meas>?. command resets all the settings to the defaults, while READ changes back to that
measurement without changing the setup parameters from the previous use.
• If you must switch between measurements, remember that Mode Setup parameters remain constant across all the
measurements in a given mode (for example, Center/Channel Frequency, Amplitude, Radio Standard, Input Selection,
Trigger Setup). You do not need to re-initialize these parameters each time you change to a different measurement.

Avoid Unnecessary Use of *RST

Remember that while *RST does not change the current Mode, it presets all the measurements and settings to their
factory defaults. This forces you to reset the instrument's measurement settings even if they use similar mode setup or
measurement settings. See
Note also that *RST may put the instrument in Single measurement/sweep for some modes.

Avoid Automatic Attenuator Setting

Many of the one-button measurements use an internal process for automatically setting the value of the attenuator. It
requires measuring an initial burst to identify the proper attenuator setting before the next burst can be measured
properly. If you know the amount of attenuation or the signal level needed for your measurement, just set it.
Note that spurious types of measurements must be done with the attenuator set to automatic (for measurements such as:
Output RF Spectrum, Transmit Spurs, Adjacent Channel Power, Spectrum Emission Mask). These types of measurements
start by tuning to the signal, then they tune away from it and must be able to reset the attenuation value as needed.

Avoid using RFBurst trigger for Single Burst Signals

RFBurst triggering works best when measuring signals with repetitive bursts. For a non-repetitive or single burst signals,
use the IF (video) trigger or external trigger, depending on what you have available.
"Minimize DUT/instrument Setup changes" on page 32.
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