MDO3000 Programmer Manual.pdf - 第616页
Commands Listed in A lphabetical Order RF:SPECTRogra m:STATE? might return 0, indicating that the spectrogram function is o ff . RF:SPECTRogram:TIMe? (Query Only) Queries the number of seconds in the spectrogram since co…
Commands Listed in Alphabetical Order
RF:SPECTRogr
am:SLICETIMe? (Query Only)
Returns the time stamp of the selected spectrogram slice (specified using
:RF:SPECTRogram:SLICESELect).
The value represents the number of seconds since spectrogram acquisitionswere
started after the instrument was powered up, or since the spectrogram was cleared
(see RF:SPE
CTRogram).
Group
RF
Syntax
RF:SPECTRogram:SLICETIMe?
Examples
RF:SPECTR:SLICETIME? returns 0.0E+0.
RF:SPECTRogram:STATE
This command switches the frequency domainspectrogramdisplayonoroff.
The spectrogram illustrates how frequency and amplitude change over time.
It is useful for monitoring slowly-changing RF events, and for identifying
low amplitude signals too subtle for the eye to catch in a regular frequency
domain display. The x-axis shows frequency, and the y-axis shows time.
Amplitude is represented by the color of the trace. Cold colors (blue, green)
indicate low amplitude, and hot colors (red, yellow) indicate high amplitude.
When acquisitions are stopped, you can navigate back through each spectrum
slice in the spectrogram by using the RF:SPECTRogram:NUMSLICEs? and
RF:SPECTRogram:SLICESELect commands.
Conditions
MDO3000, MDO4000/B, or MDO4000C models with option SA3 or SA6 only.
Group
RF
Syntax
RF:SPECTRogram:STATE {OFF|ON|0|1}
RF:SPECTRogram:STATE?
Related Commands
RF:SPECTRogram:NUMSLICEs?, RF:SPECTRogram:SLICESELect
Examples
RF:SPECTRogram:STATE ON or 1 turns the frequency domain spectrogram
display on.
MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-585
Commands Listed in Alphabetical Order
RF:SPECTRogra
m:STATE?
might return 0, indicating that the spectrogram
function is off.
RF:SPECTRogram:TIMe? (Query Only)
Queries the number of seconds in the spectrogram since continuous acquisition
started. The value returned is always <= 0.
Group
RF
Syntax
RF:SPECTRogram:TIMe?
Examples
RF:SPECTR:TIME? might return -66.8174, indicating that there were
66.8174 seconds in the spectrogram since continuous acquisition started.
RF:SPECTRUMMode
When only the frequency domain waveforms are displayed (no time domain
waveforms), you can choose whether the MDO4000/B/C should use Triggered
mode or Free Run mode. (MDO3000 series models only use Free Run mode.)
When Triggered mode is selected, you can control all trigger settings, including
Normal and Auto triggering. When Free Run mode is selected, the oscilloscope
generates RF acquisitions as fast as possible. The default is
FREErun. (On an
MDO4000/B/C series model, in order to display only the frequency domain
waveforms, you need turn off all time domain waveforms, including channels1-
4, digital channels 0 - 15, buses, time domain math waveforms, time domain
reference waveforms, and any RF vs. Time traces.)
When the MDO4000/B/C oscilloscope displays both
time and frequency domain
waveforms, then the instrument’s trigger system is in control of the Triggered
mode and the RF acquisitions.
NOTE. Note: the Free Run spectrum mod
e is only possible when all analog and
digital channels are turned off.
Conditions
MDO4000/B/C models only.
Group
RF
Syntax
RF:SPECTRUMMode {TRIGgered|FREErun}
RF:SPECTRUMMode?
2-586 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual
Commands Listed in Alphabetical Order
Arguments
TRIGgered ties
RF acquisitions to the scope's unified triggering system for all
channels.
FREErun acqui
res RF data as often as processing allows, without waiting for
trigger events.
Examples
RF:SPECTRUMMode TRIG sets the RF spectrum mode to TRIGgered.
RF:SPECTRUMMode? might return FREERUN, indicating the spectrum mode
is free run, the default.
RF:SPECTRUMTrace (No Query Form)
Resets the spectrum traces, RF_MINH old, RF_MAXHold and RF_AVErage.
Group
RF
Syntax
RF:SPECTRUMTrace {RESET}
Examples
RF:SPECTRUMTRACE RESET resets the spectrum traces: RF_MINHo ld,
RF_MAXHold and RF_AVErage.
RF:SQUELCH:STATE
This command turns the squelch control on or off for the RF Frequency vs. Time
and RF Phase vs. Time traces. When squelch is on, only the portions of these
traces where the amplitude exceeds the squelch threshold are displayed. This
prevents the display of Phase and/or Frequency for signals that are at or near noise
levels. The RF amplitude can be observed in the RF Amplitude vs. Time trace.
Conditions
MDO4000/B/C models only.
Group
RF
Syntax
RF:SQUELCH:STATE {OFF|ON|0|1}
RF:SQUELCH:STATE?
Related Commands
RF:SQUELCH:THReshold
MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-587