VOLTCRAFT DSO-1084E, DSO-1104E, DSO-1204E, DSO-1254E, DSO-1084F User guide
...
DSO1000E/F Series
Digital Storage Oscilloscope
User Manual
(Version 1.3)
Copyright Decl aration
All rights reserved; no part of this document may be reproduced or transmitted in any
form or by any means, electronic or mechanical, without prior written permission from
our company.
Our company reserves all rights to modify this document without prior notice. Please
contact our company for the latest version of this document before placing an order.
Our company has made every effort to ensure the accuracy of this document but does
not guarantee the absence of errors. Moreover, Our company assumes no
responsibility in obtaining permission and authorization of any third party patent,
copyright or product involved in relation to the use of this document.
Digital Storage Oscilloscope I
General Safety Summary
Read the following safety precautions to avoid injury and prevent damage to this
product or any products connected to it. To evade potential hazards, use this product
only as specified.
Only qualified personnel should perform maintenance.
Avoid fire or personal injury.
Use suitable power cord. Use only the power cord specified for this product and
certified for the country of use.
Connect and disconnect properly. Connect a probe with the oscillosc ope before it is
connected to measured circuits; disconnect the probe from the oscilloscope after it is
disconnected from measured circuits.
Ground the product. This product is grounded through the grounding conductor of the
power cord. To avoid electric shock, the grounding conductor must be connected to
earth ground. Before making connections to the input or output terminals of the product,
ensure that the product is properly grounded.
Connect the probe in a righ t way. The probe ground lead is at ground potential. D o
not connect the ground lead to an elevated voltage.
Check all terminal ratings. To avoid fire or shock hazard, check all ratings and
markings on the product. Ref er to the product manual for detailed information about
ratings before making connections to the product.
Do not operate without covers. Do not operate this product with covers or panels
removed.
Avoid exposed circuitry. Do not touch exposed connections and components when
power is present.
Do not operate with suspected failures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Assure good ventilation.
Do not operate in wet/damp environments.
Do not operate in an explosive atmosphere.
Keep product surfaces clean and dry.
Digital Storage Oscilloscope II
Safety Terms and Symbols
It represents the damage possibly caused to the product or other
Terms on the product. The following terms may appear on the product:
Danger It represents that har ms may be caused to you at once if you perform the
operation.
Warning It represents that latent harms may be caused to you if you perform the
operation.
Notice
properties if you perform the operation.
Characters on the product. The following characters may appear on the product:
Notice
Please read
the manual
Protective
ground terminal
Measuring
ground terminal
Chassis
ground terminal
Product Scrapping
Device Recycling
We need extract and util ize natural resources to produce this device. If you do not
reclaim the device in a proper way, some substances it contains may become harmful
or poisonous to environments or human bodies. To avoid them being released outside
and to minimize the waste of natural resources, we suggest you reasonably call back
this device to ensure proper recovery and recycling of most materials within it.
Digital Storage Oscilloscope III
Brief Introduction to the Series of digital storage oscilloscope
DSO1000E/F Series osc ill oscopes cover the bandwi dt hs from 80MHz to 200MHz, and
provide the real-time up to 1GSa/s. In addition, they have 7 inch color TFT LCD as well
as WINDOWS-style interfaces and menus for easy operation.
What’s more, the plenty menu information and the easy-to-operate buttons allow you to
gain information as much as possible in measurement; the multifunctional knobs and
the powerful shortcut keys help you save a lot of time in operation; the Auto Scale
function lets you detect sine and square waves automatically; By using the three
methods the oscilloscope provides (context-sensitive, hyperlinks, and an index), you
may master all operations on the device in quite a short time so as to greatly improve
your efficiency in production and development.
Model Channels Bandwidth Sample Rate AFG
DSO-1084E 4 80MHz 1GS/s DSO-1104E 4 100MHz 1GS/s DSO-1204E 4 200MHz 1GS/s DSO-1254E 4 250MHz 1GS/s DSO-1084F 4 80MHz 1GS/s Yes
DSO-1104F 4 100MHz 1GS/s Yes
DSO-1204F 4 200MHz 1GS/s Yes
DSO-1254F 4 250MHz 1GS/s Yes
Digital Storage Oscilloscope IV
Contents
Copyright Declaration ................................................................................................ I
General Safety Summary ....................................................................................... II
Safety Terms and Symbols .................................................................................... III
Product Scrapping ................................................................................................. III
Brief Introduction to the Series of digital storage oscilloscope ............................... IV
Contents ................................................................................................................... V
Chapter 1 Introduction ........................................................................................ 1
1.1 General Inspection ................................................................................... 2
1.2 Prepare Instrument for Use ....................................................................... 3
1.3 Accidence of the user interface ................................................................. 4
1.4 Functional Check ...................................................................................... 5
1.4.1 Connect the oscilloscope ...................................................................... 5
1.4.2 Observe the waveform ......................................................................... 5
1.5 Probe Introduction .................................................................................... 6
1.5.1 Safety ................................................................................................... 6
1.5.2 Probe Check Wizard ............................................................................. 6
1.5.3 Manual Probe Compensation ............................................................... 6
1.5.4 Probe Attenuation Setting ..................................................................... 7
Chapter 2 Function Introduction ........................................................................ 9
2.1 Menu and Control Keys .......................................................................... 10
2.2 Connector ............................................................................................... 11
2.3 Universal Knobs and Softkeys ................................................................ 11
2.4 Oscilloscope Setup ................................................................................. 12
2.5 Horizontal Controls ................................................................................. 13
2.6 Vertical System ....................................................................................... 14
2.6.1 Vertical Controls ................................................................................. 14
2.6.2 Math Operation ................................................................................... 16
2.7 Trigger System ....................................................................................... 20
Digital Storage Oscilloscope V
2.7.1 Edge Trigger ....................................................................................... 22
2.7.2 Pulse Trigger ...................................................................................... 22
2.7.3 Video Trigger ...................................................................................... 24
2.7.4 Slope Trigger ...................................................................................... 25
2.7.5 Overtime Trigger ................................................................................. 26
2.7.6 Window Trigger .................................................................................. 27
2.7.7 Pattern Trigger .................................................................................... 27
2.7.8 Interval Trigger ................................................................................... 29
2.7.9 Under Amp Trigger ............................................................................. 30
2.7.10 UAR T Triggering ................................................................................. 31
2.7.11 LIN T riggering ..................................................................................... 34
2.7.12 CAN T riggering ................................................................................... 35
2.7.13 SPI T riggering ..................................................................................... 36
2.7.14 IIC T rigger .......................................................................................... 37
2.8 Save/Recall ............................................................................................ 39
2.8.1 Internal Save and Recall ..................................................................... 40
2.8.2 External save and recall ..................................................................... 41
2.9 Measure System ..................................................................................... 42
2.9.1 Scale measurement ............................................................................ 42
2.9.2 Cursor measurement .......................................................................... 42
2.9.3 Automatic Measurement ..................................................................... 43
2.10 Acquire ................................................................................................... 47
2.10.1 XY Mode ............................................................................................ 50
2.10.2 Roll Mode ........................................................................................... 51
2.11 Display ................................................................................................... 51
2.12 Utility System .......................................................................................... 52
2.12.1 Update Firmware ................................................................................ 52
2.12.2 Self Calibration ................................................................................... 53
2.12.3 Pass/Fail ............................................................................................ 53
2.13 Fast Action Buttons ................................................................................. 54
2.13.1 AU TO SCALE ..................................................................................... 55
2.13.2 Default Setup...................................................................................... 56
Digital Storage Oscilloscope VI
Chapter 3 Waveform Generator ........................................................................ 59
3.1 Set Wave Type and Parameters ............................................................. 59
3.2 Edit Arbitrary Waveform .......................................................................... 60
3.3 Output Arbitrary Waveform...................................................................... 62
Chapter 4 Troubleshooting ............................................................................... 63
4.1 Problem Settlement ................................................................................ 63
Chapter 5 General Care and Cleaning ............................................................. 65
5.1 General Care .......................................................................................... 65
5.2 Cleaning ................................................................................................. 65
Appendix A: T echnical Specifications ................................................................... 66
Appendix B: Accessories ....................................................................................... 73
Appendix C Harmful and Poisonous Substances or Elements ............................ 74
Appendix D To replace the fuse ........................................................................... 75
Appendix E Open Source Information ............................................................ 77
Digital Storage Oscilloscope VII
Chapter 1 Introduction
General Inspection
Prepare Instrument for Use
Accidence of the user interface
Functional Check
Probe Introduction
Digital Storage Oscilloscope 1
1.1 General Inspection
Please check the instrument as following steps after receiving an oscilloscope:
Check the shipping container for damage:
Keep the damaged shipping container or cushioning mat erial until the c ontents of
the shipment have been checked for completeness and the instrument has been
checked mechanically and electrically.
Check the accessories:
Accessories supplied with the instrument are listed in "Accesso ri es" in th is manual.
If the contents are incomplete or damaged, please notify the franchiser.
Check the instrument:
In case there is any mechanical damage or defect, or the instrument does not
operate properly or fails performance tests, please notify the franchiser.
Digital Storage Oscilloscope 2
1.2 Prepare Instrument for Use
Adjust the Supporting Legs
Adjust the supporting legs properly to use them as stands to tilt the oscilloscope
upwards for stable placement of the oscilloscope as well as better operation and
observation.
Connect the Power Cord
Connect the power cord as desired. Turn the instrument on by pressing the power
switch in the lower left corner of front panel.
If the instrument does not turn on, verify that the power cord is firmly connected
(power-line voltage is automatically sensed at power-on). Also make sure that the
instrument is connected to an energized power source.
Power Switch:
To turn off the instrument, please press power switch.
Digital Storage Oscilloscope 3
1.3 Accidence of the user interface
This section will make you understand the front operation panel of this series of digital
oscilloscope at first before use.
Figure 1-2 Interface display
1. Voltcraft logo
2. Trigger Stat us
Auto: The oscillosc ope works in auto mode and is acquiring waveforms in the
absence of triggers.
Ready: All pre-triggered data have been acquired and the oscilloscope is ready to
accept a trigger.
Roll: The oscilloscope is acquiring and displaying waveform data continuously in
roll mode.
Stop: The oscilloscope has stopped acquiring waveform data.
3. Readout shows main time base setting.
4. Sample rate.
5. Main Time Base Window
Digital Storage Oscilloscope 4
CH1: to connect with the probe
PROBE COMP
6. Tigger time
7. Trigger level, Readout tells trigger level.
8. Operating Menu shows different information for respective function keys.
9. If this icon lights up/active, it means the USB disk has been connected.
10. If this icon lights up/active, it means the wave generator works
11. The inf orm ation of coupling, B andwidth and volt/div of CH1~CH4.
12. Channel Marker
13. Window displays waveform.
1.4 Functional Check
Follow the steps below to perform a quick functional check to your oscilloscope.
1.4.1 Connect the oscilloscope
Set the switch on the probe to 10X and connect the probe to Channel 1 on the
oscilloscope. First, align the slot in the probe connector with the protuberance on the
CH1 BNC and push to connect; then, turn to right to lock the probe in place; after that,
connect the probe tip and reference lead to the PROBE COMP connectors. The r e i s a
mark on the panel: Probe COMP ~2V@1KHz.
1.4.2 Observe the waveform
Press the [Auto Scale] button and y ou should see within a few seconds a square wave
of about 2V peak-to-peak at 1KHz in the display. Press the CH1 MENU button twice to
remove Channel 1. Push t h e CH2 MENU button and repeat the steps to observe CH2,
CH3 and CH4.
Digital Storage Oscilloscope 5
1.5 Probe Introduction
1.5.1 Safety
When using the probe, keep your fingers behind the guard on the probe body to avoid
electric shock. Do not touch metallic portions of the probe head while it is connected to
a voltage source. Connect the probe to the oscilloscope and connect the ground
terminal to ground before you start any measurements.
1.5.2 Probe Check Wizard
Every time you connect a probe to an input channel, you shoul d use the probe check
wizard to verify that this probe is operating correctly.
Use the vertical menu (for example, push the CH1 MENU button) to set the Probe
attenuation factor.
1.5.3 Manual Probe Compensation
Upon the first connection of a probe and an input channel, you should manually
perform this adjustment to match the probe to the input channel. Uncompensated or
Digital Storage Oscilloscope 6
Compensated correctly
Undercompensated
miscompensated probes may lead to errors or faults in measurement. To adjust the
probe compensation, follow the steps below.
1. Set the Probe option attenuation in the channel menu to 10X. Set the switch on the
probe to 10X and connect the probe to Channel 1 on the oscilloscope. If you use the
probe hook-tip, ensure it is firmly inserted onto the probe. Attach the probe tip to the
PROBE COMP ~2V@1KHz connector and the reference lead to the PROBE COM P
Ground connector. Display the channel and then press the Auto Scale button.
2. Check the shape of the displayed waveform.
Overcompensated
3. If necessary, use a nonmetallic screwdriver to adjust the variable capacity of your
probe until the shape of the waveform turns to be t he same as the above figure.
Repeat this step as necessary. See the figure below for the way of adjustment.
1.5.4 Probe Attenuation Setting
Probes are of various attenuation factors which affect the vertical scale of the si gnal.
The Probe Check function is used to verify if the P robe attenuation option matches the
attenuation of the probe.
You can push a vertical menu button (such as the CH1 MENU button) and select the
Probe option that matches the attenuation factor of your probe.
Make sure that the Attenuation switch on the probe matches the Probe option i n the
oscilloscope. Switch settings are 1X and 10X.
When the Attenuation switch is set to 1X, the probe limits the bandwidth of the
oscilloscope to 6MHz. To use the full bandwidth of the oscilloscope, be sure to set the
Digital Storage Oscilloscope 7
switch to 10X.
Digital Storage Oscilloscope 8
Chapter 2 Function Introduction
This chapter provides some general information that you need to learn before using an
oscilloscope. It contains:
Menu andCcontrol Keys
Connector
Universal Knobs and Softkeys
Oscilloscope Setup
Horizontal Controls
Vertical System
Trigger System
Save/Recall
Measure System
Acquire
Display
Utility System
Fast Action Buttons
Digital Storage Oscilloscope 9
2.1 Menu and Control Keys
As shown in the figure below:
Figure 2-1 Control keys
All the keys are described as follows:
[CH1], [CH2], [CH3], [CH4]: display setup menus of channel 1 and channel 2.
[Math]: display “Arithmetical operation” waveform menu.
[Horizontal]: Set Horizontal system.
[Trig Menu]: display Trigger control menu.
[Force Trig]: It is used for finishing acquisition of the current waveform no matter
whether the oscilloscope detects trigger, and it is mainly applied to “Normal” and
“Single” in the trigger mode.
[Default]: recall the default factory setup.
[Help]: enter the on-line help system.
[Utility]: display “UTILITY FUNCTION” menu.
[Cursors]: display the “CURSOR” menu. The [V0] knob can be used for
regulating the position of the cursor when the “CURSOR” menu is displayed and
the cursor is triggered.
[Meas]: show the “Measure” menu.
[Wave Gen]: show the waveform generator menu.
[Save Recall]: show the “Save/Recall” menu of setups and waveform.
[Display]: show the “Display” menu.
[Auto Scale]: automatically set the control state of the oscilloscope so as to
display suitable waveform.
Digital Storage Oscilloscope 10
V0:
menu options (
Press this knob to reset data (trigger holdoff, overtime of the overtime
trigger and slope trigger), select menu options and so on. Easy to operate.
Press the
waveform generator function.
[Run/Stop]: continuously acquire waveform or stop acquisiti on
[Single]: Acquire a single trigger, finish acquisition and then stop.
2.2 Connector
Figure 2-2 Connector
CH1, CH2, CH3, CH4: for an input connector of a measured signal.
EXT TRIG: be used as an input connector of an external trigger source. Use
[Trig Menu] button to select “External” trigger source (only for Edge trigger), and
the trigger signal source can be used for tri ggering in the third channel while
acquiring data.
Gen Out: Waveform signal output.
Probe compensation: The probe compensation signal is output and grounded
so that the probe is matched with the channels of the oscilloscope.
2.3 Universal Knobs and Softkeys
Universal Knob. Under different menu options, it supports selecting
MEASURE), moving cursors and levels (Slope Trigger).
Wave Gen button on the front panel to open the arbitrary
Digital Storage Oscilloscope 11
of the screen and give a full screen display of waveforms. Push it again to
show the menu options.
F1
functional. They are in charge of
selecting corresponding menu options on the screen in different menu
modes.
This functional softkey is mainly used to turn pages and confirm a
selection, such as
Hide/Show softkey. Push it to hide the menu options on the right side
-F5: These five softkeys are all multi-
‘next page’, ‘previous page’.
2.4 Oscilloscope Setup
While operating the oscilloscope, you may often use three features: Auto Scale, savi ng
a setup and recalling a setup. Hereinafter they are introduced one by one.
Auto Scale: This function can be us ed to adjust the horizontal and vertical scales of
the oscilloscope automatically and set the trigger coupling, type, positi on, slope, level
and mode, etc., to acquire a stable waveform display.
Saving a Setup: By default, the oscilloscope will save the setup each time before
being closed, and automatically recall the setup once being turned on. (Note: If you
modify the setup, please wait for more than 1 second before turning off the
oscilloscope to ensure the proper storage of new settings.) You can save 10 settings
permanently in the oscilloscope and reset them as necessary.
Recalling a Setup: The oscilloscope can recall any of your saved setups or the default
factory setup.
Default Setup: The oscilloscope is preset for normal operations when it is shipped
from the factory. This is the default setup. You may recall this setup at any time for your
requirements.
Digital Storage Oscilloscope 12
2.5 Horizontal Controls
Use the horizontal controls to change the horizontal scale and position of waveforms.
The horizontal position readout shows the time represented by the center of the screen,
using the trigger time as zero. When you change the horizontal scale, the waveform will
expand or contract to the screen center. The readout near the upper right of the screen
shows the current horizontal position in second. The oscilloscope also has an arrow
icon at the top of the graticule to indicate the horizontal position.
1. Horizontal Position Knob: Used to control the trigger position against the screen
center. Push this button to reset the trigger point back to the screen center.
AN: Used to set the horizontal position as zero.
Universal Knob
2.SEC/DIV Knob: Used to change the horizontal time scale so as to magnify or
compress the waveform horizontally. If the waveform acquisition is stopped (by using
the [Run/Stop] or [Single] button), the SEC/DIV control will expand or compress the
waveform.
Note: Press SEC/DIV Knob to enter Dual-window Mode.
Digital Storage Oscilloscope 13
Location of expanded window data in memory
Minor Window
(Expanded Window)
Single-window Mode
Dual-window Mode (Full Screen)
Major Window
Press SEC/DIV Knob again to exit Dual-window Mode.
2.6 V ert ical System
2.6.1 Vertical Controls
Vertical controls can be used to display and remove waveforms, adjust vertical scale
and position, set input parameters and perform math calculations. Each channel has a
separate vertical menu to set. See below for menu description.
Digital Storage Oscilloscope 14
1X
Vertical Position
Volts/div
1. Vertical Position Knob: Move the channel waveform up and down on the screen.
In dual-window mode, move the waveforms in both windows at the same time in a
same di rection. Push this knob to return waveforms to the vertical center positi on on
the screen. Two channels correspond to two knobs.
2. VOLTS/DIV Knob
Control the oscilloscope to magnify or attenuate the source signal of the channel
waveform. The vertical size of the display on the screen will change (increase or
decrease) to the ground level. Also you may use this knob to switch between coarse
and fine.
3. Menu (CH1, CH2, CH3, CH4): Display vert ical menu options; turn on or off the
display of channel waveforms.
Options Settings Comments
DC passes both DC and AC components of the input
Coupling
BW 20MHz
Div
DC
AC
GND
OFF
ON
Coarse
Fine
signal.
AC blocks the DC component of the input signal and
attenuates signals below 10Hz.
Ground disconnects the input signal.
Limits the bandwidth to reduce display noise; filters
the signal to eliminate noise and other unnecessary
HF components.
Selects the resolution of the VOLTS/DIV knob.
Coarse defines a 1-2-5 sequence. Fine changes the
resolution to small steps between the Coarse
settings.
Probe
10X
100X
1000X
Selects a value according to the probe attenuation
factor so as to ensure correct vertical readouts.
Reduce bandwidth to 6MHz when using a 1X probe.
Digital Storage Oscilloscope 15
The invert function turns the displayed waveform 180
trigger is also inverted.
Invert
Coupling
If the channel adopts a DC coupling mode, you can quickly measure the DC
component of the signal by observing the difference between the waveform and the
signal ground.
If the channel adopts an AC coupling m ode, the DC component in the signal is
filtered. By this mode, the AC component of the signal is displayed at a higher
sensitivity.
If the channel adopts a GND coupling mode, cut off the input signal. Inside the
channel, the channel input is connected with a zero volt reference electric level.
Fine Resolution
In the fine resolution setting, the vertical scale readout di splays the actual VOLTS/DIV
setting. The vertical scale changes only after you adjust the VOLTS/DIV control and set
to coarse.
Remove Waveform Display
To remove a waveform from the screen, first push the menu button to display the
vertical menu, then push again to remove the waveform. A channel waveform which is
unnecessary to be displayed can be used as a trigger source or for math operations.
OFF
ON
degrees, with respect to the ground level. When the
oscilloscope is triggered on the inverted signal, the
2.6.2 Math Operation
The series of scope supports many math operations between analog channels
waveforms, including addition (+), subtraction (-), multiplication (*), division (/) and FFT.
You can use cursors to measure it. The contents of this chapter:
• Units for Math Waveforms
• Math Operators
• To Adjust the Math Waveform Scale and Offset
Note: If the analog channel or the math function display is truncated (waveforms do not
display on the screen completely), the resulting math will also be truncated.
Operation Unit
Digital Storage Oscilloscope 16
Addition (+)or subtraction (-) V
multiplication (*)
division (/) None
FFT dB, Vrms,
Addition or Subtraction
Math operators perform arithmetic operations - add or subtract operation - on any two
analog input channels. When you select addition or subtraction, the Source A and
Source B values are added or subtracted point by point, and the result is displayed.
1. Press the [Math] button on the front panel to enter the MATH function menu.
2. Press the Source 1 and Source 2 softkey respectively, and then turn the Universal
Knob to select the source to do math operation. Analog channels (CH1~CH4) can be
used as Source 1 or source 2.
3. Press the Operation softkey and then turn the universal to select + or -to make
addition or subtraction operation. The resulting math waveform is displayed on the
screen and labeled with “M”.
V∧2
Scale: Press the Scale softkey, and then turn the Universal Knob to select the vertical
scale.
Digital Storage Oscilloscope 17
Multiplication and Division
Math operators perform arithmetic operations multiplication or divisi on operation on
any two analog input channels. When you select multiplication or division, the Source
1 and Source 2 values are multiplied or divided point by point and the result is
displayed.
1. Press the [Math] button on the front panel to enter the MATH function menu.
2. Press the Source 1and Source 2 softkey respectively, and then turn the Universal
Knob to select the source to do math operation. Analog channels (CH1 ~CH4) can be
used as Source 1 or source 2.
3. Press the Operation softkey and then turn the universal to select * or / to make
multiplication or division operation. The resulting math waveform is displayed on the
screen and labeled with “M”.
Scale: Press the Scale softkey, and then turn the Universal Knob to select the vertical
scale.
FFT Operation
FFT is used to compute the fast Fourier transform using analog input channels or
reference waveforms. FFT takes the digitized time record of the specified source and
transforms it to the frequency domain. When the FFT function is selected, the FFT
spectrum is plotted on the oscilloscope display as magnitude in dBV versus frequency.
The readout for the horizontal axis changes from time to frequency (Hertz) and the
vertical readout changes from volts to dB. FFT operation can facilitate the following
works:
Measure harmonic components and distortion in the system
Measure the characteristics of the noise in DC power
Analyze vibration
To display a FFT waveform:
1. Press the [Math] butt on on the front panel to open the MATH function menu.
2. Press the Operation softkey and then turn the Universal Knob to select FFT. The
resulting math waveform is displayed on the screen and label ed with “M”.
3. Press the Source softkey, and then turn the Universal Knob to select the source to
do FFT operation. Analog channels (CH1~CH4) can be used as the source.
Digital Storage Oscilloscope 18
Window
Measurement
Characteristics
Waveform
same as no windows.
Waveform
Flattop
(Triangle)
stronger
Waveform
uency accuracy
than Hanning
4. Press Center softkey and then turn the Universal Knob to adjust the frequency of
the frequency domain waveform corresponding to the horizontal center of the screen.
5. Press Span softkey and then turn the Universal Knob to adj ust the the horizontal
scale of the frequency domain waveform.
6. Pres s the Vertical Units softkey to select the unit of vertical axis. The units of the
vertical axis can be dB or Vrms which use a logarithmic scale or a linear scale to
display vertical amplitude respectively. If you need to display the FFT frequency
spectrum in a relatively larger dynamic range, dBVrms is recommended.
7. Pres s the Scale softkey to select the vert ical scal e.
8. Press the Window softkey, and then turn the Universal Knob to select an
appropriate window.
Spectral leakage can be considerably decreased when a window function is used. The
series of scope provides six kinds of FFT window functions which have different
characteristics and are applicable to measure different waveforms. You need to select
the window function according to different waveforms and their characteristics. Please
read the table below carefully to make an appropriate option according to the input
signal.
Rectangular
Hanning
Hamming
Blackman
Bartlett
Flattop
Pulse or
Transient
Periodic
Transient or
short pulse
Single frequency
signal, search for
higher order
harmonics.
Narrow band
signal with
Periodic
Special-purpose window applicable to
discontinuous waveforms. This is actually the
Better frequency, poorer a mplitude accuracy than
A litter bit better frequency resolution than
Hanning.
The best amplitude resolution; the poorest
frequency resolution
Better frequency resolution.
Better amplitude, poorer freq
Digital Storage Oscilloscope 19
9. Pres s the Show-Only softkey to select to display FFT operation results only and
not display the source channel.
Note:
Signals with DC components or deviation would cause an error or deviation of the
FFT waveform components. To reduce the DC components, set the C hannel Coupling
to AC.
To reduce the random noise and aliasing frequency components of repetitive or
single pulse, set the Acquisition of the oscilloscope to Average.
Using Cursors to measure FFT waveform
To make cursor measurements, press the Cursors button to turn the cursors, and then
press the Mode softkey to s elect Manual or Track, Use the AX and BX cursors to
measure frequency values and the difference between two frequency values (BX-AX).
Use the AY and BY cursors to measure amplitude in dB and difference in amplitude
(BY-AY).
2.7 Trigger System
The trigger determines when the oscilloscope begins to acquire data and dis play a
waveform. Once a trigger is properly set up, the oscilloscope can convert unstable
displays or blank screens to meaningful waveforms. Here introduce some basic
concepts about trigger.
Trigger Source: The trigger can be generated with multiple sources. The most
common one is the input channel (CH1~CH4). Whether the input signal is displ ayed or
not, it can trigger normal operations. Also the trigger source can be any signal
connected to an external trigger channel (only for Edge trigger).
Trigger Mode: Y ou can select the Auto or Normal mode to define how the oscilloscope
acquires data when it does not detect a trigger condition. Auto Mode performs the
acquisition freely in absence of valid trigger. It allows the generation of untriggered
waveforms with the time base set to 100ms/div or slower. Normal Mode updates the
displayed waveforms only when the oscilloscope detects a valid trigger condition.
Digital Storage Oscilloscope 20
Trigger Level
Indicates Trigger
Points
Acquisition Interval
Acquisition
Before this update, the oscilloscope still displays the old waveforms. This mode shall
be used when you want to only view the effectively triggered wveforms. In this mode,
the oscilloscope displays waveforms only after the first trigger. To perform a single
sequence acquisition, push the [Single] button.
Trigger Position: The horizontal position control establishes the time between the
trigger position and the screen center.
Trigger Level: It sets the amplitude level the signal must cross to cause an acquisition
when using the Edge or Pulse Width trigger.
Force Trigger: Used to complete an acquisition regardless of an adequate trigger
signal. This button becomes useless if the acquisition is already stopped.
Trigger Level
Holdoff: To use Trigger Holdoff, push the Trig Menu button and press Holdoff softkey.
The Trigger Holdoff function can be used to generate a stable display of complex
waveforms (such as pulse trains). Holdoff is the time between when the oscilloscope
detects one trigger and when it is ready to detect another. During the holdoff time, the
oscilloscope will not trigger. For a pulse train, the holdoff time can be adjusted to let the
oscilloscope trigger only on the first pulse in the train.
Holdoff
Interval
Holdoff
Digital Storage Oscilloscope 21
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