MDO3000 Programmer Manual.pdf - 第81页

Command Groups When the two man ual markers are turned on, the Reference Marker is no longer automatically attached to the highe st amplitude peak. It can now be moved t oa n y desired location. This enables easy measure…

Command Groups

Spectrogram sl

ices are generated by taking each spectrum and ﬂipping it on its

edge, so that it is one pixel row tall. Each new acquisition adds another slice at the

bottom of the spectrogram, and the previous acquisitions (slices) move up one

row; you can then navigate backwards through the history of the spectrogramby

selecting slice numbers to view. (The spectrogram slice trace is displayedas

the RF Normal trace.)

Spectrum Mo

de: Triggered

and Free Run

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 only uses Free Run mode.) When Triggered

mode is se

lected, 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. (To display only the frequency domain

waveforms, turn off all time domain waveforms, including channels 1- 4, digital

channels 0 - 15, buses, time domain math waveforms, time domain reference

waveforms, and any RF vs. Time traces.)

When the oscilloscope displays both time and frequency domain waveforms,

then the instrument’s trigger system is in control of the Triggered mode andthe

RF acq

uisitions.

Using Markers in the

Frequency Domain for

Measurement and Analysis

For frequency domain measurements, up to 11 automatic markers are available

to assist with quickly identifying the frequency and amplitude of peaks in the

spe

ctrum based upon user threshold and excursion settings. If more peaks meet

the criteria than the desired number of markers, then the highest amplitudepeaks

are shown. Two manual markers are also available for measuring non-peak areas

of interest, and to measure Noise Density and Phase Noise. If manual markersare

off, the reference marker is automatically placed on the highest amplitudepeak.

With manual markers on, the reference marker becomes the “A” manual marker.

utomatic peak markers are on by default.

Each automatic marker has a readout associated with it. These can be absolute

r delta readouts. An absolute marker readout shows the actual frequency and

amplitude of the associated marker. A delta marker readout shows the frequency

and amplitude of the automatic markers relative to the Reference Marker.

The Reference Marker’s readout indicates absolute frequency and amplitude,

regardless of the readout type. (It is marked on the display with a red R in a

triangle.) The marker measurement readouts are absolute in dBm or relativetothe

reference marker in dBc (dB below carrier amplitude).

The threshold and excursion settings deﬁne which peaks are marked automatically.

The threshold is a minimum amplitude that a signal must cross to be a valid peak.

If the threshold is lower, more peaks will tend to qualify for markers. If the

threshold is higher, fewer peaks tend to qualify for markers. The excursion is how

far a signal needs to fall in amplitude between marked peaks to be another valid

peak. If the excursion is low, more peaks will tend to qualify for markers. Ifthe

excursion is high, fewer peaks will tend to qualify for markers.

2-50 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual

Command Groups

When the two man

ual markers are turned on, the Reference Marker is no longer

automatically attached to the highest amplitude peak. It can now be moved toany

desired location. This enables easy measurement of any part of the spectrum,

as well as delta measurements to any part of the spectrum. This also lets you

measure non-peak spectral content of interest. The readouts for manual markers

indicate frequency, amplitude and noise (just like automatic marker readouts).

Taking Auto

matic

Measurements in the

Frequency Domain

You can take three automatic measurements in the frequency domain:

1. Channel Power (CP) — The total power within the bandwidth, deﬁned by

the Channel Width.

2. Adjacent Channel Power Ratio (ACPR) — The power in the main channel

and the ratio of channel power to main power, for the upper and lower halves of

each adjacent channel.

3. Occupied Bandwidth (OBW) — The bandwidth that contains the speciﬁed

percentage of power within the analysis bandwidth.

Triggering using RF

Power L evel as a Source;

Searching

The ability to use the RF power level as the source for edge triggering and

searching is provided standard with the MDO4000/B and MDO4000C with

option SA3 or SA6 series models. With the MDO4TRIG (Advanced Trigger)

application module installed, the RF power level can also be used as the source

for p

ulse width, time-out, runt, logic, and sequence triggering. (See page 2-76,

Trigger Command Group.) A number of search commands are also available.

(See page 2-61, Search Command Group.)

Transfe rring and Saving

RF Trace Information

u can perform waveform transfer commands and queries using RF traces. (See

page 2-95, Waveform Transfer Command Group.)

traces can be saved to an .ISF or .CSV ﬁle for subsequent recall to any of the

4 internal reference memory locations. The oscilloscope can also save, butnot

recall, RF acquisitions as .TIQ ﬁles. You can import .TIQ ﬁles into Tektronix

SignalVu-PC software (PC based), SignalVu software (oscilloscope based),

RSAVu software (PC based) or into a Tektronix real-time spectrum analyzer for

pulse analysis and demodulation analysis. (See page 2-58, Save and Recall

Command Group.)

NOTE. The RF input replaces the Aux Input connector on the front panel,

therefore aux-in commands and arguments are not supported on the MDO4000/B,

MDO4000C with option SA3 or SA6, and MDO3000 models with 4-channels.

MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-51

Command Groups

Table 2-37: RF C

ommands

Item Description

MARKER:M<x>:AMPLitude:

ABSolute?

This query ret

urns the actual amplitude (vertical) value of the either of the two manual markers

that are available for frequency domain traces, in dBm.

MARKER:M<x>

:AMPLitude:

DELTa?

This query returns the delta amplitude (vertica l) value of either of the two manual markers that

are available for frequency domain traces, in relation to the Reference Marker.

MARKER:M<x>:FREQuency:

ABSolute

This command speciﬁes the actual frequency (horizontal) value of either of the two manual

markers tha

t a re available for frequency domain traces.

MARKER:M<

x>:FREQuency:

DELTa?

This query

returns the delta frequency (horizontal) value of either of the two manual markers

that are available for frequency domain traces, in relation to the Reference Marker.

MARKER:M<x>:NOISEDensity?, This c ommand returns the noise density of the RF_NORMal trace at the speciﬁed marker

position in <RF Units>/Hz units, where <RF Units> are the units speciﬁed by the command

RF:UNIts

MARKER:

M<x>:PHASENoise?

This com

mand returns the phase noise of the RF_NORMal trace at the speciﬁed marker

position in dBc/Hz units.

MARKER:

MANual

This command switches on or off the manual markers a and b that are available for frequency

domain traces.

MARKER:PEAK:EXCURsion This command speciﬁes the excursion value, in user-selected units, for the frequency domain

trace a

utomatic peak markers. You can select the units with the command RF:UNIts.

MARKER:PEAK:MAXimum

This c

ommand speciﬁes the maximum number of frequency domain trace peaks that should

have automatic markers associated with them. This can be a number between 1 and 11.

MARKER:PEAK:STATE This command switches on or off the automatic peak markers that are available for frequency

domain traces. The default is 1 (on). There are up to 11 automatic markers.

MARKER:PEAK:THReshold

This command speciﬁes the threshold value, in the same vertical units as the source waveform,

of t

he automatic peak markers available f or frequency domain traces. (Use the RF:UNIts

to specify the units.)

MAR

KER:REFERence

This command changes the Center Frequency to the frequency indicated by the Reference

Marker, in effect moving the Reference Marker to the center of the screen.

MARKER:REFERence:

AMPlitude?

This query returns the amplitude (vertical) value of the Reference Marker in dBm when markers

e turned on (using the command MARKER:PEAK :STATE or MARKER:MANual).

MARKER:REFERence:

REQuency?

his query returns the frequency of the Reference Marker when the frequency domain

trace markers have been turned on (using either the command MARKER:P EAK:STATE or

MARKER:MANual).

MARKER:TYPe

This command speciﬁes the marker type (either DELTa or ABS olute) to use when the automatic

markers for the frequency domain traces are turned on. To turn on the automatic markers,

use the command MARKER:PE AK:STATE.

RF:CLIPPing? Returns a boolean indicating whether the RF input is “clipping” due to input over/under-range

detection.

RF:DETECTionmethod:MODe This command speciﬁes whether the R F detection within the oscilloscope occurs automatically

or manually. T he default is AUTO. If you set the detection method mode to MANual, you

are then able to use the related

RF:DETECTionmethod commands to specify detection

method options for the frequency dom ain traces (the options are

MINUSpeak, SAMple,

PLUSpeak and AVErage).

2-52 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual