MDO3000 Programmer Manual.pdf - 第614页
Commands Listed in A lphabetical Order running, are ig nored. The query form returns the currently selected spectrogram slice. T o use this com mand, first turn on the spectrogram ( RF:SPECTRogram:ST A TE ). Then query th…
Commands Listed in Alphabetical Order
RF:SPECTRogr
am (No Query Form)
Clears the spectrogram.
Conditions
Available for MDO4000/B/C and MDO3000 series models only.
Group
RF
Syntax
RF:SPECTRogram {CLEAR}
Arguments
CLEAR clears the spectrogram.
Examples
RF:SPECTR CLEAR clears the spectrogram.
RF:SPECTRogram:NUMSLICEs? (Query Only)
This query returns the number of spectrogram slices that are currently being
rendered. A spectrogram slice is a section of the spectrogram representing one
interval, or slice, of time in the spectrogram record.
Conditions
MDO3000, MDO4000/B, or MDO4000C models with option SA3 or SA6 only.
Group
RF
Syntax
RF:SPECTRogram:NUMSLICEs?
Related Commands
RF:SPECTRogram:STATE,RF:SPECTRogram:NUMSLICEs?,
Examples
RF:SPECTRogram:NUMSLICEs? might return 85, indicating that the spectrogram
is made up of 85 individual time slices.
RF:SPECTRogram:SLICESELect
This command specifies the spectrogram slice number that is to be displayed.
The slice can only be selected or changed when acquisitions have been stopped.
As soon as acquisitions start again, the slice number is reset to 0 (the latest slice).
Attempts to select a slice number outside of range, or when acquisitions are
MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-583
Commands Listed in Alphabetical Order
running, are ig
nored. The query form returns the currently selected spectrogram
slice.
To use this com
mand, first turn on the spectrogram (RF:SPECTRogram:STATE).
Then query the number of slices (RF:SPECTRogram:NUMSLICEs?). Stop the
acquisition when you’ve reached the number of desired slices. Then select the
slice to display (RF:SPECTRogram:SLICESELect).
Each slice of the spectrogram corresponds to a single RF acquisition. The FFT
samples the entire spectrum for the incoming signal (at the rate with which new
spectrums are acquired). The newest spectrum is on the bottom edge of the
spectrogram, and the oldest is on the top edge. When the oscilloscope is stopped,
you can sc
roll “back in time” through the spectrogram using the spectrum slice
control. When you select a spectrogram slice, it is displayed in the bottom
window as the RF Normal trace.
NOTE. When acquisitions are stopped and the spectrogram is displayed, the
spectrogram slice trace is displayed as the RF Normal frequency domain trace.
Condi
tions
MDO3000, MDO4000/B, or MDO4000C models with option SA3 or SA6 only.
Group
RF
Syntax
RF:SPECTRogram:SLICESELect <NR1>
RF:SPECTRogram:SLICESELect?
Related Commands
RF:SPECTRogram:STATE, RF:SPECTRogram:NUMSLICEs?,
Arguments
<NR1> is an integer that specifies the spectrogram slice number that is to be
displayed.
For the MDO4000/B/C models, allowable slice numbers range from 0 to –327 in
full-screen mode, and 0 to –147 in split-screen mode. For MDO300
0models,
there is no split-screen mode – the slice numbers always range from 0 to –197.
(The range is negative because the numbering starts with the latest slice (0) and
proceeds backwards in time.)
Examples
RF:SPECTRogram:SLICESELect –5 would select the slice that is five
acquisitions before the most recent one.
RF:SPECTRogram:SLICESELect? might return 0, indicating that the latest
spectrogram slice is being displayed.
2-584 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual
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