digimess DS25 User Manual

DS25 Colour Digital Storage Oscilloscope User Manual

1

digimess

®

DS25

Portable Colour Digital Storage Oscilloscope

User's Manual

DS25 Colour Digital Storage Oscilloscope User Manual

2

www.digimessinstruments.co.uk

DS25 Colour Digital Storage Oscilloscope User Manual

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Copyright 2006

Änderungen und Irrtümer vorbehalten.

Nachdruck, auch auszugsweise, nur mit schriftlicher Genehmigung des Herstellers.

Alle Rechte vorbehalten.

Subject to alterations, errors excepted.

Reprints, also in extracts, are only allowed with written permission of the manufacturer.

All rights reserved.

DS25 Colour Digital Storage Oscilloscope User Manual

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WARRANTY

The perfect working order of the oscilloscope is guaranteed for 12 months as from delivery.
There is no warranty for faults arising from improper operation or from changes made to the
oscilloscope or from inappropriate application.
If a fault occurs please contact or send your oscilloscope to:

The oscilloscope should be sent in appropriate packing - if possible in the original packing. Please
enclose a detailed fault report (functions working incorrectly, deviating specifications and so on)
including unit type and serial number.
Would you also kindly verify warranty cases by enclosing your supply delivery note. Any repairs
carried out without reference to a valid warranty will initially be at the owner’s expense.
Should the warranty have expired, we will, of course, be glad to repair your oscilloscope as per our
General Terms Of Assembly And Service.

Agents details :

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Table of Contents

General Safety Requirements ______________________________________________ 7
Safety Terms and Symbols_________________________________________________ 8
General Characteristics of the DS25 Colour Digital Storage Oscilloscope __________ 9
Junior User’s' Guidebook________________________________________________ 10

Introduction to the Front Panel and the User's Interface of the DS series Oscilloscope __ 11
How to Carry out the General Inspection _______________________________________15
How to Carry out the Function Inspection ______________________________________16
How to Implement Probe Compensation________________________________________18
How to Set the Probe Attenuation Coefficient____________________________________ 19
How to Use the Probe Safely __________________________________________________ 20
How to Implement Auto-calibration____________________________________________ 21
Introduction to the Vertical System ____________________________________________22
Introduction to the Horizontal System__________________________________________ 23
Introduction to the Trigger System_____________________________________________24

Advanced User's Guidebook ______________________________________________ 25

How to Set the Vertical System ________________________________________________ 26
Implementation of Mathematical Manipulation Function__________________________ 32
Application of VERTICAL POSITION and VOLTS/DIV Knobs ____________________ 33
How to Set the Horizontal system______________________________________________ 34
Main Time Base ____________________________________________________________ 35
Window Setting_____________________________________________________________ 36
Window Expansion__________________________________________________________37
How to Set the Trigger System ________________________________________________38
Trigger Control_____________________________________________________________ 39
Edge Trigger _______________________________________________________________39
Video Trigger ______________________________________________________________ 42
How to Operate the Function Menu____________________________________________ 45
How to Implement Sampling Setup ____________________________________________ 45
How to Set the Display System ________________________________________________ 48

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Persist ____________________________________________________________________ 50

XY Format ____________________________________________________________________50

How to Save and Recall a Wave Form __________________________________________52
Save and Recall the Wave Form _______________________________________________53
How to Carry out the Auxiliary System Function Setting __________________________54
Do Self Cal (Self-Calibration) _________________________________________________ 55
SYS STAT (System State)_____________________________________________________55
How to Conduct Automatic Measurement_______________________________________ 57
Measure___________________________________________________________________ 57
How to Carry out Cursor Measurement ________________________________________59
Cursor Measurement________________________________________________________ 60
How to Use Executive Buttons_________________________________________________62
AUTOSET_________________________________________________________________ 62

Examples of Application _________________________________________________ 63

Example 1: Measurement of Simple Signals _____________________________________63
Example 2: Gain of the Amplifier in the Metering Circuit__________________________ 64
Example 3: Capture a Single Signal____________________________________________ 65
Example 4: Analyze the Details of a Signal ______________________________________ 67
Example 5: Application of X-Y Function________________________________________ 69
Example 6: Video Signal Trigger ______________________________________________71

Fault Treatment________________________________________________________ 73
Appendix A: Technical Specifications ______________________________________ 74
Appendix B: Enclosure __________________________________________________ 79
Appendix C: Maintenance, Cleaning and Repair _____________________________ 79

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General Safety Requirements

Before operating, please read the following safety precautions to avoid any
possible injury and prevent this product or any other products connected from
damage. In order to avoid any contingent danger, this product is only to be used
within the range specified.

Only qualified technicians should implement maintenance procedures.

Prevention of Fire or Bodily Injury.
Use the correct power line. Only use the power cord specially provided for this

product or one which has been approved.
Connect or Disconnect Correctly. When the probe or testing wire is connected to the

power lead, please do not connect and disconnect the probe or testing wire freely.
Product Grounding. This product is grounded through the power lead grounding

conductor. In order to prevent any electric shock, the grounding conductor must be
connected to the ground. It requires guarantee that this product has been already
grounded correctly before any connection with its input or output terminal.

Connect the probe correctly. The grounding end of the probe corresponds to the
grounding phase. Please don't connect the grounding end to the positive phase.
Pay attention to the nominal values of all terminals. In order to prevent any fire or
electric shock risks, please pay attention to all the nominal values and marks of this
product. Before implement any connections for this product, please read the user's
manual of this product to understand the information about the rated values further.

Do not operate without the instrument cover installed. If the cover or panel has
already been removed, please don't operate this product.

Use the proper fuse. Only the fuse complying with the specified type and nominal
value for this product can be used.

Avoid touching any exposed circuit. When the product is on power, please don't
touch the uncovered contacts and parts.

Please do not operate if a fault is suspected. If suspecting damage to this product,
please contact the qualified maintenance personnel for check.

Keep a good ventilation condition. Please consult the detailed installation
instruction in the user's manual so that this product can be erected correctly, keeping it
under a good ventilation condition.

Do not operate in a moist environment.
Do not operate in an explosive environment .
Keep the product’s surface clean and dry.

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Safety Terms and Symbols

Terms in this manual. The following terms may appear in this manual:

Warning. A warning statement indicates the conditions and actions which may

endanger the life safety.

Note. A note statement indicates the conditions and actions which may cause

damage to this product or other property.

Terms on the product. The following terms may appear on this product:
Danger: It indicates that there may be an immediate injury to you when you encounter

this mark.
Warning: It indicates that there may not be an immediate injury to you when you

encounter this mark.

Note: It indicates that there may be damage to this product or other property.
Symbols on the products. The following symbol may appear on the products:

High Voltage Please Consult the Manual. Protective Ground End Grounding End for Measurement Earth End on the Shell

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General Characteristics of the DS25
Colour Digital Storage Oscilloscope

 Bandwidth of 25MHz;
 Record length of 6,000 points for each channel;
 Sampling rates of 100MS/s for each channel;
 Read-out with the cursor;
 Five automatic measurement functions;
 Color liquid crystal display with high resolution and high contrast including

adjustable back light;

 Store and recall waveforms;
 Automatic setting function provides fast set up;
 Multiple-waveform calculation function;
 Detect average and peak values of a waveform;
 Digital real-time oscilloscope;
 Edge and video triggering function;
 USB communication ports;
 Different continuous display times;
 User interface in two languages.

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Junior User’s' Guidebook

This chapter deals with the following topics mainly:

 Introduction to the front panel and the user’s interface of the DS series oscilloscope
 How to carry out general inspection
 How to carry out functional inspection
 How to make a probe compensation
 How to set the probe attenuation coefficient
 How to use the probe safely
 How to implement an auto-calibration
 Introduction to the vertical system
 Introduction to the horizontal system
 Introduction to the trigger system

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Introduction to the Front Panel and the User's Interface of the
DS series Oscilloscope

When you get a new-type oscilloscope, you should get acquainted with its front panel
at first and the DS series digital storage oscilloscope is no exception. This chapter
makes a simple description of the operation and function of the front panel of the DS
series oscilloscope, enabling you to be familiar with the use of the DS series
oscilloscope in the shortest time. The DS series oscilloscope offers a simple front
panel with distinct functions for completing basic operations, in which the knobs and
function pushbuttons are included. The knobs have the functions similar to other
oscilloscopes. The 5 buttons in the column on the right side of the display screen are
menu selection buttons (defined as F1 to F5 from top to bottom respectively), through
which, you can set the different options for the current menu. The other pushbuttons
are function buttons, through which, you can enter different function menus or obtain
a specific function application directly.

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Fig. 1 The Front Panel of a DS series Oscilloscope

Function Buttons

Fig. 2 Explanatory Drawing for Operation of the DS series Oscilloscope

Back-light

Adjustment

Menu Selection

Vertical Control

Connector

Horizontal

Control

Trigger
Control

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Fig. 3 Illustrative Drawing of Display Interfaces

1. The Trigger State indicates the following information:

Auto: The oscilloscope is under the Automatic mode and is

collecting the waveform under the non-trigger state.

Trig' d: The oscilloscope has already detected a trigger signal and is

collecting the after-triggering information.

Ready: All pre-triggered data have been captured and the

oscilloscope has been already ready for accepting a trigger.

Scan: The oscilloscope captures and displays the waveform data

continuously in the scan mode.

Stop: The oscilloscope has already stopped the waveform data

acquisition.

2. Waveform Viewing Area.

3. The purple pointer indicates the horizontal trigger position, which can be adjusted

by the horizontal position control knob.

4. The reading shows the time deviation between the horizontal trigger position and

the screen centre line, which equals 0 in the screen center.

5. This reading shows the time deviation between the horizontal trigger position and

the window centre line, which is regarded as 0 in the window center.

6. It indicates the current function menu.

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7. It indicates the operation options for the current function menu, which changes

with the function menus.

8. The purple pointer shows the trigger level position.

9. The reading shows the trigger level value.

10. The reading shows the trigger source.

11. It shows the selected trigger type:

Rising edge triggering

Falling edge triggering

Video line synchronous triggering

Video field synchronous triggering

12. The reading shows the window time base set value.

13. The reading shows the main time base set value.

14. The two yellow dotted lines indicate the size of the viewing expanded window.

15. The icon shows the coupling mode of the CH2 channel.

“—“ indicates the direct current coupling
“ ~” indicates the AC coupling

16. The reading shows the vertical scale factor (the Voltage Division) of the CH2

channel.

17. The icon indicates the coupling mode of the CH1 channel:

The icon "–" indicates the direct current coupling
The icon "~" indicates the AC coupling

18. The reading indicates the vertical scale factor (the Voltage Division) of the CH1

channel.

19. The information shows the zero point positions of CH1 or CH2 channel.

20. The yellow pointer shows the grounding datum point (zero point position) of the

waveform of the CH2 channel. If the pointer is not displayed, it shows that this
channel is not opened.

21. The red pointer indicates the grounding datum point (zero point position) of the

waveform of the CH1 channel. If the pointer is not displayed, it shows that the
channel is not opened.

22. The positions of two purple dotted line cursors measurements.

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How to Carry on the General Inspection

After you receive a new DS series oscilloscope, it is recommended that you should
make a check of the instrument according to the following steps:

1. Check whether there is any damage caused by transportation.

If it is found that the packaging carton or the foamed plastic protection cushion has
suffered serious damage, do not throw it away until the complete device and its
accessories satisfy the electrical and mechanical property tests.

2. Check the Accessories

The supplied accessories have been already described in the Appendix B
“Accessories” of this Manual. You can check whether there is any loss of accessories
with reference to this description. If it is found that there is any accessory lost or
damaged, please get in touch with the distributor of digimess responsible for this
service.

3. Check the Complete Instrument

If it is found that there is damage to the appearance of the instrument, or the
instrument does not work normally, or fails in the performance test, please get in
touch with the digimess distributor responsible for this business. If there is damage to
the instrument caused by the transportation, please keep the package.

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How to Carry out the Function Inspection

Make a quick function check to verify the normal operation of the instrument,
according to the following steps:

1. Connect the Instrument to the Power and Push down the Power Switch Button.

The instrument carries out all self-check items and shows the prompt “Press any Key
Enter the Operating Mode”. Press the “UTILITY” button to get access to the
“FUNCTION” menu and push down F2 the menu selection button to call out the
function “Recall Factory”. The default attenuation coefficient set value of the probe in
the menu is 10X, shown as Fig. 4.

Fig. 4 Power on the Instrument

2. Set the Switch in the Oscilloscope Probe as 10X and Connect the
Oscilloscope with CH1 Channel.

Align the slot in the probe with the plug in the CH1 connector BNC, and then tighten
the probe with rotating it to the right side.

Connect the probe tip and the ground clamp to the connector of the probe
compensator, shown as Fig. 5.

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Probe comp

CH1

Fig. 5 Connection of the Probe

3. Press the AUTOSET Button.

The square wave of 1 KHz frequency and 5V peak-peak value will be displayed in
several seconds (see Fig. 6).

Fig. 6 Autoset

Check CH2 by repeating Step 2 and Step 3.

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How to Implement the Probe Compensation

When connecting the probe with any input channel for the first time, perform this
adjustment to match the probe with the input channel. A probe which is not
compensated or presents a compensation deviation will result in a measuring error or
mistake. For adjusting the probe compensation, please carry out the following steps:

1. Set the attenuation coefficient of the probe in the menu as 10X and that of the
switch in the probe as 10X, and connect the oscilloscope probe with the CH1
channel. If a probe hook tip is used, ensure that it keeps in close touch with the
probe. Connect the probe tip with the signal connector of the probe compensator
and connect the reference wire clamp with the ground wire connector of the
probe connector, and then press the button AUTOSET (see Fig. 5).

2. Check the displayed wave forms and regulate the probe till a correct
compensation is achieved (see Fig. 7 and Fig. 8).

Fig. 7 Displayed Wave Forms of the Probe Compensation

3. Repeat the steps mentioned if necessary.

Fig. 8 Adjust Probe

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How to Set the Probe Attenuation Coefficient

The probe has several attenuation coefficients, which will influence the vertical scale
factor of the oscilloscope.

If it is required to change (check) the set value of the probe attenuation coefficient,
press the function menu button of the channels used, then push down the selection
button corresponding to the probe till the correct set value is shown.

This setting will be valid all the time before it is changed again.

Note: The attenuation coefficient of the probe in the menu is preset to 10X when

the oscilloscope is delivered from the factory.

Make sure that the set value of the attenuation switch in the T5100 probe is the same
as the menu selection of the probe in the oscilloscope.

The set values of the probe switch are 1X and 10X (see Fig. 9).

Fig. 9 Attenuation Switch

Note: When the attenuation switch is set to 1X, the T5100 probe will limit the

bandwidth of the oscilloscope in 5MHz. If it is needed to use the whole bandwidth
of the oscilloscope, the switch must be set to 10X.

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How to Use the Probe Safely

The safety guard ring around the probe body protects your finger against the electric
shock, shown as Fig. 10.

Fig. 10 Finger Guard

Warning: In order to avoid suffering from an electric shock, please keep your

finger behind the safety guard ring of the probe body during operation.

In order to protect you from suffering an electric shock during your use of the

probe, do not touch the metal part of the probe tip when the probe is connected to
the signal source.

Before making any measurements, please connect the probe to the instrument and

connect the ground terminal to the earth.

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How to Implement Auto-calibration

The auto-calibration application can make the oscilloscope reach the optimum
condition rapidly to obtain the most accurate measurement value. You can carry out
this application program at any time, but when the range of variation of the ambient
temperature is up to or over 5C, this program must be executed.

For the performing of the self-calibration, all probes or wires should be disconnected
with the input connector first. Then, press the “UTILITY” button to call out the
FUNCTION menu; push down the F3 menu selection button to choose the option
“ Do Self Cal”; finally, run the program after confirming that everything is ready now.

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Introduction to the Vertical System

Shown as Fig.11, there are a series of buttons and knobs in VERTICAL
CONTROLS. The following practices will gradually direct you to be familiar with

the use of the vertical setting.

Fig. 11 Vertical Control Zone

1. Use the button “VERTICAL POSITION” knob to show the signal in the center
of the waveform window. The “VERTICAL POSITION” knob functions the
regulating of the vertical display position of the signal. Thus, when the
“VERTICAL POSITION” knob is rotated, the pointer of the earth datum point
of the channel is directed to move up and down following the wave form.

Measuring Skill

If the channel is in the DC coupling mode, you can rapidly measure the DC
component of the signal through the observation of the difference between the wave
form and the signal ground.

If the channel is in the AC mode, the DC component will be removed by filtration.
This mode helps you display the AC component of the signal with a higher
sensitivity.

2. Change the Vertical Setting and Observe the Consequent State Information
Change.

With the information displayed in the status bar at the bottom of the waveform
window, you can determine any changes in the channel vertical scale factor.

 Rotate the vertical “VOLTS/DIV” knob and change the “Vertical Scale Factor

(Voltage Division) ”, it can be found that the scale factor of the channel
corresponding to the status bar has been changed accordingly.

 Press buttons of “CH1 MENU”, “CH2 MENU” and “MATH MENU”, the

operation menu, symbols, wave forms and scale factor status information of the
corresponding channel will be displayed in the screen.

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Introduction to the Horizontal System

Shown as Fig.12, there are a button and two knobs in the “HORIZONTAL
CONTROLS”. The following practices will gradually direct you to be familiar with

the setting of the horizontal time base.

Fig. 12 Horizontal Control Zone

1. Use the horizontal “SEC/DIV” knob to change the horizontal time base setting
and observe the consequent status information change. Rotate the horizontal
“SEC/DIV” knob to change the horizontal time base, and it can be found that the
“Horizontal Time Base” display in the status bar changes accordingly. The
horizontal scanning speed steps from 5ns up to 5s in the sequence of 1=2=5.

2. Use the “HORIZONTAL POSITION” knob to adjust the horizontal position of
the signal in the waveform window. The “HORIZONTAL POSITION” knob is
used to control the triggering displacement of the signal or for other special
applications. If it is applied to triggering the displacement, it can be observed that
the wave form moves horizontally with the knob when you rotate the
“Horizontal Position” knob.

3. With the “HORIZONTAL MENU” button pushed down, you can set and
initiate the Window Expansion.

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Introduction to the Trigger System

Shown as Fig.13, there are a knob and four buttons in the “TRIGGER
CONTROLS”. The following practices will direct you to be familiar with the setting

of the trigger system gradually.

Fig. 13 Trigger Control Zone

1. Press the “TRIG MENU” button and call out the trigger menu. With the
operations of the 5 menu selection buttons, the trigger setting can be changed.

2. Use the “LEVEL” knob to change the trigger level setting.
With the rotation of the “LEVEL” knob, it can found that the trigger indicator in
the screen will move up and down with the rotation of the knob. With the
movement of the trigger indicator, it can be observed that the trigger level value
displayed in the screen changes.

3. Press the button “SET TO% 50” to set the trigger level as the vertical mid point
values of the amplitude of the trigger signal.

4. Press the “FORCE TRIG” button to force a trigger signal, which is mainly
applied to the “Normal" and "Single” trigger modes.

5. The “TRIG VIEW” button is used to reset the trigger horizontal position.

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Advanced User's Guidebook

You should already be familiar with the initial operations of “VERTICAL
CONTROLS”, “HORIZONTAL CONTROLS” and “TRIGGER CONTROLS”,

and the functions of the function areas, buttons and knobs in the front panel of the DS
series oscilloscope. Based on the introduction of the previous Chapter, the user should
have an intimate knowledge of the determination of the change of the oscilloscope
setting through observing the status bar. If you have not been familiar with the
above-mentioned operations and methods yet, we advise you to read the section of
“Chapter One Junior Users' Guidebook”.

This chapter will deal with the following topics mainly:

 How to Set the Vertical System
 How to Set the Horizontal System
 How to Set the Trigger System
 How to Carry on the Sampling Setup
 How to Set the Display System
 How to Implement the Storage and Call-out Operations
 How to Carry out the Auxiliary Function Setting
 How to Carry out the Automatic Measurement
 How to Carry out the Cursor Measurement
 How to Use Executive Buttons

It is recommended that you read this chapter carefully to get acquainted with the
various measurement functions and other operating methods of the DS series
oscilloscope.

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How to Set the Vertical System

The VERTICAL CONTROLS includes three menu buttons such as CH1 MENU,
CH2 MENU and MATH MENU, and four knobs such as VERTICAL POSITION ,
VOLTS/DIV ( one group for each of the two channels ).

Setting of CH1 and CH2

Every channel has an independent vertical menu and each item is set respectively
based on the channel.

With the “CH1 MENU” or “CH2 MENU” menu button pushed down, the system
shows the operation menu of the corresponding channel (see Fig. 14).

Fig. 14 Channel Setting Menu

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The description of the Channel Menu is shown in the following list:

Function Menu Setting Description

Coupling AC

DC

Block the AC component in the input signal.
Unblock the AC and DC components in the
input signal.

Channel OFF

ON

Close the measurement channel.
Open the measuring channel.

Probe 1X

10X
100X
1000X

Choose one according to the probe
attenuation factor to make the vertical scale
reading accurate.

Inverted OFF

ON

The wave form is displayed normally.
Initiate the wave form inverted function.

1. Setting Channel Coupling

Taking the Channel 1 for example, the measured signal is a square wave signal
containing the direct current bias. The operation steps are shown as below:

(1). Press the CH1 MENU button and call out the CH1 SETUP menu.
(2). Press the F1 menu selection button and select the Coupling item as “AC” to

set the channel coupling as ac mode, under which the direct current
component in the signal will be blocked.

Then, press the F1 menu selection button again and select the Coupling item as
“DC”, setting the channel coupling as dc mode, under which both dc and ac
components in the signal will be unblocked.

The wave forms are shown as Fig. 15 and Fig. 16.

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Fig. 15 AC Coupling

Fig. 16 DC Coupling

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2. Setting the Channel “ON/OFF”

Taking the Channel 1 for example, the operation steps are shown as below:
(1). Press the CH1 MENU button and call out the CH1 SETUP menu.
(2). Press the F2 menu selection button and select the Channel as OFF, with

Channel 1 switched off.

(3). Press F2 menu selection button again, select the channel as ON, with

Channel 1 is switched on.

3. Regulate the Attenuation Ratio of the Probe

In order to match the attenuation coefficient of the probe, it is required to adjust
the attenuation ratio coefficient of the probe through the operating menu of the
Channel accordingly. If the attenuation coefficient of the probe is 1:1, that of the
oscilloscope input channel should also be set to 1X to avoid any errors presented
in the displayed scale factor information and the measured data.

Take the Channel 1 as an example, the attenuation coefficient of the probe is 1:1,
the operation steps is shown as follows:

(1). Press the CH1 MENU button, access CH1 SETUP menu.
(2). Press the F3 menu selection button and select 1X for the probe.
The Figure 17 illustrates the setting and the vertical scale factor when the probe

of the attenuation coefficient of 1:1. is used.

Fig. 17 Regulation of the Attenuation Ratio of the Probe

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A List of the Attenuation Coefficients of Probes and the Corresponding Menu
Settings.

Attenuation Coefficient of the Probe

Corresponding Menu Setting

1:1 1X
10:1 10X
100:1 100X
1000:1 1000X

5. Setting of Wave Form Inverted

Wave form inverted: the displayed signal is turned 180 degrees against the phase
of the earth potential.

Taking the Channel 1 for example, the operation steps are shown as follows:
(1). Press the CH1 MENU button and get access to the CH1 SETUP menu.
(2). Press the F4 menu selection button and select ON in the Inverted. The wave

form inverted function is initiated.

(3). Press the F4 menu selection button again and select OFF for Inverted item.

The function of wave form inverted is closed off.

For the screen display, see Fig. 18 and Fig. 19.

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Fig. 18 Wave Form not Inverted

Fig. 19 Wave Form Inverted

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Implementation of Mathematical Manipulation Function

The Mathematical Manipulation function is used to show the results of the additive
and subtraction operations between Channel 1 and Channel 2.

Taking the additive operation between Channel 1 and Channels 2 for example, the
operation steps are as follows:

1. Press the MATH MENU button and call out the WAVE MATH menu.

2. Press the F3 menu selection button and choose CH1+CH2. The green calculated
wave form M is displayed in the screen; press the F3 menu selection button again,
the wave form M is closed off (see Fig. 20).

Fig. 20 Wave Form resulted from CH1 +CH2 Mathematical Manipulation

The corresponding FCL (Functional Capabilities List) of the Wave Form

Calculation

Setting Description

CH1-CH2 Subtract the Channel 2 wave form from the Channel 1

wave form.

CH2-CH1 Subtract the Channel 1 wave form from the Channel 2

wave form.

CH1+CH2 Add the Channel 1 wave form to the Channel 2.

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Application of VERTICAL POSITION and VOLTS/DIV Knobs

1. The .VERTICAL POSITION knob is used to adjust the vertical positions of the
wave forms of all Channels (including those resulted from the mathematical
operation).
The analytic resolution of this control knob changes with the vertical division.

2. The VOLTS/DIV knob is used to regulate the vertical resolution of the wave
forms of all channels (including those obtained from the mathematical
manipulation), which can determine the sensitivity of the vertical division with
the sequence of 1-2-5. The vertical sensitivity goes up when the knob is rotated
clockwise and goes down when the knob is rotated anticlockwise.

3. When the vertical position of the channel wave form is adjusted, the screen shows
the information concerning the vertical position at the lower left corner (see
Fig.21).

Fig. 21 Information about Vertical Position

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How to Set the Horizontal system

The HORIZONTAL CONTROLS includes the HORIZONTAL MENU button and
such knobs as HORIZONTAL POSITION and SEC/DIV.

1. HORIZONTAL POSITION knob: this knob is used to adjust the horizontal
positions of all channels (include those obtained from the mathematical
manipulation), the analytic resolution of which changes with the time base.

2. SEC/DIV knob: it is used to set the horizontal scale factor for setting the main
time base or the window.

3. HORIZONTAL MENU button: with this button pushed down, the screen shows
the operating menu (see Fig. 22).

Fig. 22 Time Base Mode Menu

The description of the Horizontal Menu is as follows:

Function Menu Setting Description

Main Time Base The setting of the horizontal main time base is

used to display the wave form.
Window Setup A window area is defined by two cursors.
Window
Expansion

The defined window area for display is

expanded to the full screen.

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Main Time Base

Press the F1 menu selection button and choose the Main Time Base. In this case, the
HORIZONTAL POSITION and SEC/DIV knobs are used to adjust the main

window. The display in the screen is shown as Fig. 23.

Fig. 23 Main Time Base

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Window Setting

Press the F2 menu selection button and choose Set Window. The screen will show a
window area defined by two cursors. In this case, the HORIZONTAL POSITION
and SEC/DIV knobs can be used to adjust the horizontal position and size of this
window area (see Fig. 24).

Fig. 24 Window Setting

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Window Expansion

Press the F3 menu selection button and choose Zone Window. As a result, the
window area defined by two cursors will be expanded to the full screen size (see Fig.

25).

Fig. 25 Zone Window

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How to Set the Trigger System

When the oscilloscope begins to collect the data and display the wave form depends
on a trigger. Once it is set correctly, the trigger can transfer the unstable display into a
meaningful wave form.

When beginning to collect data, the oscilloscope will collect adequate data to draw the
wave form at the left side of the trigger point at first. It will continuously perform the
data acquisition while waiting for the trigger condition. After a trigger is detected, the
oscilloscope will continuously collect data enough to draw the wave form at the right
side of the trigger point.

One knob and four function menu buttons are included in the trigger control zone.
LEVEL: Trigger the level control knob and set the signal voltage corresponding to

the trigger point.
SET TO %50: Set the trigger level as the vertical mid point value of the amplitude of

the trigger signal.
FORCE TRIG: It is a force trigger button for the generation of a trigger signal,

which is mainly used in the “Normal” and "Single” triggering modes.

TRIG VIEW: Trigger the resetting of the horizontal position.
TRIG MENU: It is a trigger menu button. When it is pressed, an operation menu will

be presented in the screen, shown as Fig. 26.

Fig. 26 Trigger Mode Menu

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Trigger Control

There are two trigger modes: Edge Trigger and Video Trigger. Each trigger mode
uses different function menu. The switching between two modes can be implemented
by pressing the F1 menu selection button.

Edge Trigger: It happens when the trigger input passes through a given level along
the set direction.

Video Trigger: Carry out the field or line video trigger of the standard video signal.
The Edge and Video Trigger menus are described respectively as below:

Edge Trigger

Under the Edge Trigger mode, a trigger happens in the trigger threshold value of the
input signal edge. When the Edge Trigger is selected, a trigger will occur in the
rising or falling edge of the input signal.

The Edge Trigger Menu is shown as Fig. 27.

Fig. 27 Edge Trigger Menu

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The Edge Trigger Menu is described as below:

Function Menu Setting Description

Slope Rising

Falling

Set a trigger on the rising edge of the signal.
Set a trigger on the falling edge of the signal.

Source CH1

CH2
EXT

EXT/5

Set Channel 1 as the trigger signal of the source.
Set Channel 2 as the trigger signal of the source.
Set the external trigger channel as the trigger signal
of the source.
Divide the External Trigger Source by 5 to expand
the external trigger level range.

Mode Auto

Normal

Single

Collect the wave form even if there is not trigger
condition is detected.
Collect the wave form only when the trigger
condition is fulfilled.
Collect a wave form when a trigger is detected then
stop sampling.

Coupling DC

AC
HF Rjc

LF Rjc

Block the direct current component.
Unblock all components.
Block the high-frequency signal and only unblock
the high-frequency component.
Block the low-frequency signal and only unblock
the low frequency component.

Make such settings in Channel 1 as Rising for Slop, Auto for Mode and DC for
Coupling. The operation steps are as follows:

1. Press the TRIG MENU button and call out the trigger menu.

2. Press the F1 menu selection button and select Edge for Type.

3. Press the F2 menu selection button and select Rising for Slope.

4. Press the F3 menu selection button and choose CH1 for Source.

5. Press the F4 menu selection button and choose Auto for Mode.

6. Press the F5 menu selection button and choose AC for Coupling. The display

in the screen is as Fig. 28.

7. Press the F2 menu selection button again and choose Falling for Slope. For

the screen display, see Fig. 29.

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Fig. 28 Wave Form Triggered on the Rising Edge

Fig. 29 Wave Form Triggered on the Falling Edge

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Video Trigger

After choosing “Video Trigger”, a trigger is possible in field or line of NTSC, PAL
or SECAM standard video signal.

The operation menu of Video Trigger is shown as Fig. 30.

Fig. 30 Video Trigger Menu

The description of the Video Trigger menu is shown the following table:

Function Menu Setting Description

Polarity Normal

Inverted

Applicable to the video signal of low black level.
Applicable to the video signal of high black level.

Source CH1

CH2
EXT

EXT/5

Set Channel 1 as the trigger signal of the source.
Set Channel 2 as the trigger signal of the source.
Set the external input channel as the trigger signal of
the source.
Divide the external trigger source by 5 and expand
the external trigger level range.

Sync Line

Field

Set a trigger synchronization in the vide line.
Set a trigger synchronization in the video field.

The operation steps for setting Channel 1 in Video Trigger Mode are as below:

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1. Press the TRIG MENU button and get access to the trigger menu.

2. Press the F1 menu selection button and choose Video for Type.

3. Press the F2 menu selection button and choose Normal for Polarity.

4. Press the F3 menu selection button and choose CHI1 for Source.

5. Press the F4 menu selection button and choose Field for Sync. The screen

display is shown as Fig. 31.

6. Press the F4 menu selection button again and choose Line for Slope. The

screen display is shown as Fig. 32.

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Fig. 31 Wave Form Triggered in the Video Field

Fig. 32 Wave Form Triggered in the Video Line

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How to Operate the Function Menu

The function menu control zone includes 6 function menu buttons and 3
immediate-execution buttons: SAVE/REL, MEASURE, ACQUIRE, UTILITY,

CURSOR, DISPLAY, AUTOSET, RUN/STOP and HARDCOPY.

How to Implement Sampling Setup

Press the ACQUIRE button and the menu is displayed in the screen, shown as Fig.

33.

Fig. 33 ACQU MODE Menu

The description of the Sampling Setup Menu is shown as follows:

Function Menu Setting Description

Sampling General sampling mode.
Peak Detection It is used for the detection of the jamming

burr and the possibility of reducing the
confusion.

Average value It is used to reduce the random and

don’t-care noises, with the optional
number of averages.

Averages 4, 16, 64,

128

Choose the number of averages.

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Change the ACQU Mode settings and observe the consequent variation of the wave
form displayed.

Fig. 34 Peak Detect mode, under which the burrs on the falling edge of the square wave

can be detected and the noise is heavy.

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Fig. 35 Common ACQU Mode display, in which no burr can be detected.

Fig. 36 The displayed wave form after the noise is removed under the Average Mode, in

which the average number of 64 is set.

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How to Set the Display System

Push down the DISPLAY button and the menu displayed in the screen is shown as
Fig. 37.

Fig. 37 Display Set Menu

The description of the Display Set Menu is shown as follows:

Function Menu Setting Description

Type Vectors

Dots

The space between the adjacent sampling points in

the display is filled with the vector form.
Only the sampling points are displayed.

Persist OFF

1sec
2sec
5sec
Infinite

Set the persistence time for each sampling point.

Format YT

XY

Show the relative relation between the vertical
voltage and the horizontal time.
Channel 1 is displayed on the horizontal axis and
Channel 2 on the vertical axis.

Carry Bitmap

Vectors

The data transmitted in communication are in the
bitmap form.
The data transmitted in communication are in the
vector form.

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Display Type: With the F1 menu selection button pushed down, you can shift
between Vectors and Dots types. The differences between the two display types can
be observed through the comparison between Fig. 38 and Fig.39.

Fig. 38 Display in the Vector Form

Fig. 39 Display in Dots form

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Persist

When the Persist function is used, the persistence display effect of the picture tube
oscilloscope can be simulated: the reserved original data is displayed in fade color and
the new data is in bright color. With the F2 menu selection button, different
persistence time can be chosen: 1sec, 2sec, 5sec, Infinite and Closed. When the
“Infinite” option is set for Persist time, the measuring points will be stored until the
controlling value is changed (see Fig. 40).

Fig. 40 Infinite Persistence Display

XY Format

This format is only applicable to Channel 1 and Channel 2. After the XY display
format is selected, Channel 1 is displayed in the horizontal axis and Channel 2 in the
vertical axis; the oscilloscope is set in the un-triggered sample mode: the data are
displayed as bright spots and the sampling rate is 1MS/s and can not be changed.

The operations of all control knobs are as follows:

 The Vertical VOLTS/DIV and the Vertical POSITION knobs of Channel 1 are

used to set the horizontal scale and position.

 The Vertical VOLTS/DIV and the Vertical POSITION knobs of Channel 2

are used to set the vertical scale and position continuously.

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The following functions can not work in the XY Format:

 Reference or digital wave form
 Cursor
 Auto Set
 Time base control
 Trigger control

Operation steps:

1. Press the DISPLAY button and call out the Display Set Menu.

2. Press the F3 menu selection button and choose the form as XY. The display

format is changed to be XY mode (see Fig. 41).

Fig. 41 XY Display Mode

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How to Save and Recall a Wave Form

Press the SAVE/REL button, you can save and call out the wave forms in the
instrument. The menu displayed in the screen is shown as Fig. 42.

Fig. 42 Wave Form Save Menu

The description of the Wave Form Save Menu is shown as the following table:

Function Menu Setting Description

Source CH1

CH2
MATH

Choose the wave form to be saved.

WAVE A , B

C , D

Choose the address in or from which the

waveform is saved or can be get access to..

Save Save the wave form of the source in the

selected address.

CHA OFF

ON

Switch on or off the display of the stored

wave form .

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Save and Recall the Wave Form

The DS series oscilloscope can store four wave forms, which can be displayed with
the current wave form at the same time. The stored wave form called out can not be
adjusted.

In order to save the wave form of the channel CH1 into the address A, the operation
steps should be followed:

1. Press the F1 menu selection button and choose CH1 for Source.

2. Press the F2 menu selection button and choose A for Wave.

3. Press the F3 menu selection button and save the wave form.

4. Press the F4 menu selection button and choose ON for CHA. The stored wave

form A will be displayed in the screen. The voltage level and time base level will
also be shown at the upper left corner of the display area at the same time (see
Fig. 43).

Fig. 43 Wave Saving

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How to Carry on the Auxiliary System Function Setting

Press the UTILITY button and the menu is displayed in the screen as Fig. 45.

Fig. 45 Function Menu

The description of the Auxiliary Function Menu is shown as the following table.

Function Menu Setting Description

System Status Display the system function menu.
Recall Factory Call out the factory settings.
Do Self Cal Carry out the self-calibration procedure.
Language Chinese

ENGLISH

Choose the display language of the
operating system.

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Do Self Cal (Self-Calibration)

The self-calibration procedure can improve the accuracy of the oscilloscope under the
ambient temperature to the greatest extent. If the change of the ambient temperature is
up to or exceeds 5C, the self-calibration procedure should be executed to obtain the
highest level of accuracy.

Before executing the self-calibration procedure, disconnect the probe or wire and the
input connector. Then press the F3 menu selection button and choose “Do Self Cal”.
After confirming it is all set, push down F3 button and choose “Do Self Cal”,
entering the self-calibration procedure of the instrument.

SYS STAT (System State)

Press the F1 menu selection button and choose “SYS STAT” item. The menu pops up
in the screen as Fig. 46.

Fig. 46 SYS STAT Menu

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The “SYS STAT” menu is described as the following table:

Function Menu Setting Description

Horizontal Show the horizontal parameter of the channel.
Vertical Show the vertical parameter of the channel.
Trigger Show the parameters of the trigger system.
Misc Adjust the Date and Time.

After entering into the SYS STAT menu, choose the corresponding function, with the
corresponding parameters shown in the screen. If press the F1 menu selection button
and choose the function item “Horizontal”, the Horizontal System State will be
displayed in the screen. Press any other function button and exit from the SYS STAT
menu (see Fig. 47).

Fig. 47 Horizontal System State

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How to Conduct the Automatic Measurement

With the Measure button pressed down, an automatic measurement can be
implemented. There are 5 types of measurements and 4 measurement results can be
displayed simultaneously.

Press the F1 menu selection button to choose Source or Type menu. You can choose
the channel to be measured from the Source menu and choose the measurement Type
(Freq, Cycle, Mean, PK–PK, RMS and None). The menu is displayed as Fig. 48.

Fig. 48 Measure Menu

Measure

Four automatic measured values can be shown one time at maximum for the wave
form of each channel. Only if the wave form channel is in the ON state can the
measurement be carried out. No automatic measurement can be made for the saved or
the mathematically manipulated wave form, or in the XY or Scan format.

Measure the frequency, the peak-to-peak value of the Channel CH1 and the mean, the

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RMS of the Channel CH2, according the following steps:

1. Press the F1 menu selection button and choose Source.

2. Press the F2 menu selection button and choose CH1.

3. Press the F3 menu selection button and choose CH1.

4. Press the F4 menu selection button and choose CH2.

5. Press the F5 menu selection button and choose CH2.

6. Press the F1 menu selection button and choose Type.

7. Press the F2 menu selection button and choose Freq.

8. Press the F3 menu selection button and choose Pk-Pk.

9. Press the F4 menu selection button and choose Mean.

10. Press the F5 menu selection button and choose Cyc RMS.
The measured value will be displayed in the reading window automatically (see Fig.

49).

Fig. 49 Automatic Measurement

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How to Carry on the Cursor Measurement

Press the CURSOR button to display the cursor measurement function menu (CURS
MEAS) in the screen, which includes Voltage Measurement and Time
Measurement, shown as Fig. 50.

Fig. 50 CURS MEAS Menu

The description of the cursor measurement menu is shown as the following table:

Function Menu Setting Description

Type OFF

Voltage
Time

Switch off the cursor measurement.
Display the voltage measurement cursor and
menu.
Show time measures the cursor and menu.

Source CH1, CH2 Choose the channel generating the wave form to

which the cursor measurement will be applied.
Delta Read the difference between cursors.
Cursor 1 Read the position of Cursor 1 (the Time is read

with reference to the horizontal trigger position

and the Voltage is to the ground point).
Cursor 2 Read the position of Cursor 1 (the Time is read

with reference to the horizontal trigger position

and the Voltage is to the ground point).

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Cursor Measurement

When carrying out the cursor measurement, the position of Cursor 1 can be adjusted
with the CURSOR 1 (VERTICAL POSITION) knob of Channel 1, and that of
Cursor 2 can be adjusted with the CURSOR 2 (VERTICAL POSITION) knob of
Channel 2.

Perform the following operation steps for the voltage cursor measurement of the
channel CH1:

1. Press CURSOR and recall the Curs Meas menu.

2. Press the F1 menu selection button to choose Voltage for Type, with two purple

dotted lines displayed along the horizontal direction of the screen, which
indicating CURSOR 1 and CURSOR 2.

3. Press the F2 menu selection button and choose CH1 for Source.

4. Adjust the positions of CURSOR 1 and CURSOR 2 according to the measured

wave form, with the absolute value of the voltage amplitude difference between
Cursor 1 and Cursor 2 displayed in the increment window. The current position
of Cursor 1 is displayed in the Cursor 1 window and that of Cursor 2 is displayed
in the Cursor 2 window (see Fig. 51).

Fig. 51 Wave Form of Voltage Cursor Measurement

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Carry out the following operation steps for the time cursor measurement of the
channel CH1:

1. Press “CURSOR” and recall the CURS MEAS menu.

2. Press the F1 menu selection button and choose Time for Type, with two purple

dotted lines displayed along the vertical direction of the screen, which indicating
Cursor 1 and Cursor 2.

3. Press the F2 menu selection button and choose CH1 for Source.

4. Adjust the positions of CURSOR 1 and CURSOR 2 according to the measured

wave form, with the cycle and frequency of Cursor 1 and Cursor 2 displayed in
the increment window. The current position of Cursor 1 is displayed in the Cursor
1 window and that of Cursor 2 is displayed in the Cursor 2 window (see Fig. 52).

Fig. 52 Wave Form of Cursor Measurement

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How to Use Executive Buttons

The executive buttons include AUTOSET, RUN/STOP and HARDCOPY.

AUTOSET

This button is used for the automatic setting of all control values of the instrument to
generate the wave form suitable for observation. Press the AUTOSET button and the
oscilloscope will perform the fast automatic measurement of the signal.

The function items of AUTOSET are shown as the following table:

Function Items Setting

Acquisition Mode Current
Vertical Coupling DC
Vertical Scale Adjust to the proper division.
Bandwidth Full
Horizontal Level Middle
Horizontal Sale Adjust to the proper division
Trigger Type Current
Trigger Source Show the minimum number of channels.
Trigger Coupling Current
Trigger Slope Current
Trigger Level Mid-point Setting
Trigger Mode Auto
Display Format YT

RUN/STOP:

Enable or disable the waveform sampling.

Notice:

Under the Stop state, the vertical division and the horizontal time base of the

wave form can be adjusted within a certain range, in other words, the signal
can be expanded in the horizontal or vertical direction.
When the horizontal time base equal to or is less than 50ms, the horizontal
time base can be expanded for 4 divisions downwards.

HARDCOPY:

Press the HARDCOPY button and the oscilloscope will transmit the

current screen display to the computer connected with it. The receiving software should be
installed in the superior computer, which should be connected the through the RS232
interface.

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Examples of Application

Example 1: Measurement of Simple Signals

Observe an unknown signal in the circuit, and display and measure rapidly the
frequency and peak-to-peak value of the signal.

1. Carry out the following operation steps for the rapid display of this signal:

1. Set the probe menu attenuation coefficient as 10X and that of the switch in the

probe switch as 10X.

2. Connect the probe of Channel 1 to the measured point of the circuit.

3. Push down the AUTOSET button.
The oscilloscope will implement the AUTOSET to make the wave form optimized,

based on which, you can further regulate the vertical and horizontal divisions till the
waveform meets your requirement.

2. Perform Automatic Measurement

The oscilloscope can measure most displayed signals automatically. Complete the
following operations for the measurement of frequency, cycle, mean and peak-to-peak
value:

1. Press the MEASURE button to show the automatic measurement function menu.

2. Press the F1 menu selection button and choose Source, with the Source menu

displayed.

3. Press the F2, F3, F4 and F5 menu selection buttons and choose CH1.

4. Press the F1 menu selection button again and choose Type, with the Type menu

displayed.

5. Press the F2 menu selection button and choose Freq.

6. Press the F3 menu selection button and choose Period.

7. Press the F4 menu selection button and choose Mean.

8. Press the F5 menu selection button and choose Pk-Pk.
Then, the frequency, cycle, mean and peak-to-peak value will present in the menu and

change periodically (see Fig. 53).

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Fig. 53 Waveform of Automation Measurement

Example 2: Gain of the Amplifier in the Metering Circuit

Set the probe menu attenuation coefficient as 10X and that of the switch in the probe
as 10X.

Connect the oscilloscope CH1 channel with the circuit signal input end and the CH2
channel to the output end.

Operation Steps

1. Push down the AUTOSET button and the oscilloscope will automatically adjust

the waveforms of the two channels into the proper display state.

2. Push down the MEASURE button to show the MEASURE menu.

3. Press the F1 menu selection button and choose Source.

4. Press the F2 menu selection button and choose CH1.

5. Press the F3 menu selection button and choose CH2.

6. Press the F1 menu selection button again and choose Type.

7. Press the F2 menu selection button and choose Pk-Pk.

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8. Press the F3 menu selection button and choose Pk-Pk.

10. Read the peak-to-peak values of Channel 1 and Channel 2 from the displayed

menu (see Fig. 54).

11. Calculate the amplifier gain with the following formulas.

Gain = Output Signal / Input signal

Gain (db) = 20×log (gain)

Fig. 54 Wave Form of Gain Measurement

Example 3: Capture the Single Signal

The digital storage oscilloscope takes the lead in providing the convenience capturing
of such non-periodic signals as pulse and burr, etc.. If you intent to capture a single
signal, you can not set the trigger level and the trigger edge unless you have a
particular priori knowledge of this signal. For example, if the pulse is the logic signal
of a TTL level, the trigger level should be set to 2 volts and the trigger edge be set as
the rising edge trigger. If it is uncertain as to the signal, you can make an observation

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of it in advance under the automatic or ordinary mode to determine the trigger level
and the trigger edge.

The operation steps are as follows:

1. Set the probe menu attenuation coefficient to 10X and that of the switch in the

probe to 10X.

2. Adjust the VOLTS/DIV and SEC/DIV knobs to set up a proper vertical and

horizontal ranges for the signal to be observed.

3. Press the button ACQUIRE to display the ACQUIRE Mode menu.

4. Press the F2 menu selection button and choose Peak Detect.

5. Press the TRIG MENU button to display the Trigger Mode menu.

6. Press the F1 menu selection button and choose Edge as the trigger type.

7. Press the F4 menu selection button and choose Single as the trigger mode.

8. Press the F2 menu selection button and choose Rising as the slope.

9. Rotate the LEVEL knob and adjust the trigger level to the mid-value of the

signal to be measured.

10. If the Trigger State Indicator at the top of the screen does not indicate Ready,

push down the RUN/STOP button and start Acquire, waiting the emergence of
the signal in conformity with the trigger conditions. If a signal reaches to the set
trigger level, one sampling will be made and then displayed in the screen. With
this function, any random occurrence can be captured easily. Taking the burst
burr of larger amplitude for example, set the trigger level to the value just greater
than the normal signal level, and then push down the RUN/STOP button and
wait. When there is a burr occurring, the instrument will trigger automatically and
record the wave form generated during the period around the trigger time. With
the HORIZONTAL POSITION knob in the horizontal control area in the panel
rotated, you can change the horizontal position of the trigger position to obtain
the negative delay, making an easy observation of the waveform before the burr
occurs (see Fig. 55).

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Fig. 55 Capture the Single Signal

Example 4: Analyze the Details of a Signal

Observe the Signal Containing Noises

If the signal is interfered by the noise, the noise may cause a failure in the circuit. For
the analyzing of the noise in detail, please operate the instrument according to the
following steps:

1. Press the ACQUIRE button to display the ACQU MODE menu.

2. Press the F2 menu selection button and choose Peak Detect.
In this case, the screen display contains the wave form of a random noise. Especially

when the time base is set as Low Speed, then noise peak and burr contained in the
signal can be observed with the peak detection (See Fig. 56).

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Fig. 56 Wave Form of the Signal Containing Noises

Separate Noises from the Signal

When analyze the wave form of a signal, you should remove the noise contained in it.
For the reduction of the random noise in the oscilloscope display, please operate the
instrument according to the following step:

1. Press the ACQUIRE button to show the ACQU MODE menu.

2. Press the F3 menu selection button and choose Average.

3. Press the F4 menu selection button and observe the wave form obtained from

averaging the wave forms of different average number.

After the averaging, the random noise is reduced and the detail of the signal is easier
to be observed. Shown as follows, after the noise is removed, the burrs on the rising
and falling edges appears (see Fig. 57).

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]

Fig. 57 Wave Form of the Noise-Removed Signal

Example 5: Application of X-Y Function

Examine the Phase Difference between Signals of two Channels

Example: Test the phase change of the signal after it passes through a circuit network.
Connect the oscilloscope with the circuit and monitor the input and output signals of

the circuit.
For the examination of the input and output of the circuit in the form of X-Y

coordinate graph, please operate according to the following steps:

1. Set the probe menu attenuation coefficient for 10X and that of the switch in the

probe for 10X.

2. Connect the probe of channel 1 to the input of the network and that of Channel 2

to the output of the network.

3. Push down the AUTOSET button, with the oscilloscope turning on the signals of

the two channels and displaying them in the screen.

5. Adjust the VOLTS/DIV knob, making the amplitudes of two signals equal in the

rough..

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6. Push down the DISPLAY button and recall the DISP SET menu.

7. Press the F3 menu selection button and choose XY for Format.

The oscilloscope will display the input and terminal characteristics of the network
in the Lissajous graph form.

8. Adjust the VOLTS/DIV and VERTICAL POSITION knobs, optimizing the

wave form.

9. With the elliptical oscillogram method adopted, observe and calculate the phase

difference (see Fig. 58).

Fig. 58 Lissajous Graph

Based on the expression sinq =A/B or C/D, where, q is the phase difference angle,
and the definitions of A, B, C, and D are shown as the graph above. As a result, the
phase difference angle can be obtained, namely, q =± arcsin (A/B ) or ± arcsin (C/D).
If the principal axis of the ellipse is in the I and III quadrants, the determined phase
difference angel should be in the I and IV quadrants, that is, in the range of (0- π /2)
or (3π / 2- 2π). If the principal axis of the ellipse is in the II and IV quadrants, the
determined phase difference angle is in the II and III quadrants, that is, within the
range of (π / 2 - π) or (π- 3π /2).

The signal must be

centered and kept in the

horizontal direction.

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Example 6: Video Signal Trigger

Observe the video circuit of a television, apply the video trigger and obtain the stable
video output signal display.

Video Field Trigger

For the trigger in the video field, carry out operations according to the following
steps:

1. Press the TRIG MENU button to display the trigger menu.

2. Press the F1 menu selection button and choose Video for Type.

3. Press the F2 menu selection button and choose Normal for Polarity.

4. Press the F3 menu selection button and choose CH1 for Source.

5. Press the F4 menu selection button and choose Field for Sync.

6. Adjust the VOLTS/DIV, VERTICAL POSITION and SEC/DIV knobs to

obtain a proper wave form display (see Fig. 59).

Fig. 59 Wave Form Obtained from Video Field Trigger

Video Line Trigger

For the trigger in the video line, please operate according to the following steps:

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1. Push down the TRIG MENU button to display the trigger menu.

2. Press the F1 menu selection button and choose Video.

3. Press the F2 menu selection button and choose Normal for Polarity.

4. Press the F3 menu selection button and choose CH1 for Source.

5. Press the F4 menu selection button and choose Line for Sync.

6. Adjust the VOLTS/DIV, VERTICAL POSITION and SEC/DIV knobs to

obtain the proper wave form display (see Fig. 60).

Fig. 60 Wave Form Obtained from the Video Line Trigger

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Fault Treatment

1. In the case of that the oscilloscope is still in the black-screen state without any

display after the power is switch on, implement the following fault treatment
procedure.

 Check whether the power connection is connected properly.
 Check whether the power switch is pushed down to the designated position.
 Restart the instrument after complete the checks above.
 If the product still does not work normally, please contact your digimess

representative.

2. After acquiring the signal, carry out the following operations if the wave form of

the signal is not displayed in the screen.

 Check whether the probe is properly connected to the signal connecting wire.
 Check whether the signal connecting wire is correctly connected to the BNC

(namely, the channel connector).

 Check whether the probe is properly connected with the object to be measured.
 Check whether there is any signal generated from the object to be measured ( the

trouble can be shot by the connection of the channel from which there is a signal
generated with the channel in fault).

 Make the signal acquisition operation again.

3. The measured voltage amplitude value is 10 times greater or smaller than the

actual value.

Check whether the channel attenuation coefficient conforms with the attenuation ration
of the probe used in practical application.

4. There is wave form displayed, but it is not stable.

 Check whether the Source item in the TRIG MODE menu is in conformity with

the signal channel used in the practical application.

 Check on the trigger Type item: The common signal chooses the Edge trigger

mode for Type and the video signal the Video. Only if a proper trigger mode is
applied, the wave form can be displayed steadily.

 Try to change the trigger coupling into the high frequency suppress and the low

frequency suppress to smooth the high frequency or low frequency noise
triggered by the interference.

5. No Display Responses to the Push-down of RUN/STOP.

Check whether Normal or Signal is chosen for Polarity in the TRIG MODE menu and
the trigger level exceeds the wave form range.
If it is, make the trigger level is centered in the screen or set the trigger mode as Auto.
In addition, with the AUTOSET button pressed, the setting above can be completed

DS25 Colour Digital Storage Oscilloscope User Manual

74

automatically.

6. After the AVERAGE value sampling is set in the ACQU MODE or the a longer

duration is set in the DISP MODE, the display rate is slowed down.

It is a normal phenomenon.

Appendix A: Technical Specifications

Unless otherwise specified, the technical specifications applied are applicable to the
probe with the attenuation switch setting 10X and the DS series digital oscilloscope.
Only if the oscilloscope fulfills the following two conditions at first, can these
specification standards be reached.

 This instrument should run for more than 30 minutes continuously under the

specified operating temperature.

 If the change range of the operating temperature is up to or exceeds 5C, open the

system function menu and execute the “Auto-calibration” procedure.

All specification standards can be fulfilled, except the one(s) marked with the word
“Typical”.

Sampling

ACQU Mode Sample

Peak Detection
Average

Sampling Rate 100 MS/s

Input

Input Coupling DC, AC
Input Impedance 1MΩ± 2%, connected with 20pF± 3pF in parallel
Probe attenuation c

oefficient

1X, 10X, 100X, 1000X

Max. Input Voltage 300V, Peak Value

Level

Sampling Rate Range 10S/s to 100MS/s
Waveform interpolation (sinx) /x
Record Length 6000 sampling points per channel
Scanning Speed Range
(S/div )

5ns/div to 5s/div, according to the stepping mode of

1- 2.5- 5.
Accuracy of Sampling Rate
and Delay Time

± 100ppm ( for any time interval equal to or greater

than 1ms)
Measuring Accuracy of Time
Interval (∆T) (Full
Bandwidth)

Single: ± (One Sampling Interval Time +100ppm ×

Reading +0.6ns)

>Averages of 16: ± (One Sampling Interval Time

+100ppm× Reading +0.4ns)

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DS25 Colour Digital Storage Oscilloscope User Manual

76

Vertical

A/D Converter Resolution of 8 bits, with the sampling carried out

in two channels at the same time.
Sensitivity (Volt/division)
Range (V/div )

5mV/div- 5V/div (at the input BNC)

Displacement Range ± 10div (5mV- 5V )
Simulative Bandwidth 25MHz
Single Bandwidth Full Bandwidth
Low frequency respond (AC
Coupling, - 3dB)

≥

5Hz (at BNC)

Rising Time (Typical, at
BNC )

≤17.5ns

DC Gain Accuracy ± 5%
DC Measuring Accuracy
( Average for ACQU MODE)

The voltage difference (∆V) between any two

points on the wave form after averaging the

captured wave forms of more than 16: ± (5%

Reading + 0.05 divisions).

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77

Trigger

DC Coupling Channel 1 and Channel 2: 1div (DC to Full

Bandwidth )
EXT 100mV(DC to Full Bandwidth)
EXT/5 500mV(DC to Full Bandwidth)

Trigger Sensitivity
(Edge Trigger)

AC Coupling It is the same as the DC coupling in case of

50Hz or more.
Internal ± 6 divisions from the screen center.

EXT ± 600mV

Trigger Level Range

EXT/5 ± 3V
Inside ± 0.3 div

EXT ± (40mV + 6% of Set Value)

Trigger Level
Accuracy (Typical): It
is applicable to the
signal with the rising
and falling time ≥ 20ns

EXT/5 ± (200mV +6% of Set Value)

Trigger Displacement Preliminary Trigger: 655 divisions

Post Trigger: 4 divisions.

Set Level to 50%
(Typical)

Operation under the condition of input signal frequency ≥
50Hz.
Internal Peak-to-peak value of 2 divisions
EXT 400mV

Trigger Sensitivity
(Video trigger, typical)

EXT/5 2V

Signal System and
Line/Field Frequency
(Video Trigger Type)

Supports the NTSC, PAL and SECAM broadcast systems
for any field frequency of line frequency.

Measurement

Cursor Measurement Voltage difference (∆V) and time difference (∆T)

between cursors.
Automatic
Measurement

Peak-to-Peak Value, Average , RMS , Frequency and

Cycle

Probe

1X Position 10X Position
Bandwidth DC: up to 4 MHz DC: up to full bandwidth
Attenuation Ratio 1: 1 10: 1
Compensation Range 10pf to 35pf
Input Resistance 1MΩ± 2% 10MΩ± 2%
Input Electric Capacity 85pf- 115pf 14.5pf- 17.5pf
Input Voltage 150 V DC 300 V DC

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78

General Technical Specifications
Display

Display Type 7.8 inch Color LCD (Liquid Crystal Display)
Display Resolution 640 (Horizontal) × 480 (Vertical) Pixels
Display Colors 256 Colors

Output of the Probe Compensator

Output Voltage
(Typical )

Approx 5V, with the Peak-to-Peak value equal to or
greater than 1MΩ of load.

Frequency (Typical ) Square wave of 1KHz

Power

Mains Voltage 100-240 VAC RMS, 50Hz, CAT II
Power Consumption < 15W
Fuse 1A, T grade, 250V

Environment

Temperature Working temperature: 0 to +40 C

Storage temperature: -20 to +60 C
Relative Humidity ≤ 90%
Height

Operating: 3,000 m

Non-operating: 15,000 m
Cooling Method Natural convection

Mechanical Specifications

Dimension 350mm× 157mm×120mm
Weight 1 kilogram (without battery option)

Interval Period of Adjustment:

One year is recommended for the calibration interval period.

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79

Appendix B: Enclosure

Standard Accessories:

 Passive probe: 2 pcs, 1.2 m, 1:1 (10:1)
 CDROM software
 USB cable
 Mains power cord.
 User's manual

Options:

 DS25-BATT – Lithium battery

Appendix C: Maintenance, Cleaning and
Repair

General Maintenance

Please don't store or put the instrument in the place where the liquid crystal display
will be directly exposed to the sunlight for a long time.

Caution: The instrument or probe should not be stained with the spraying agent,

liquid and solvent to avoid any damage to it.

Cleaning

Check the probe and instrument regularly according to their operating state. Clean the
external surface of the instrument following the steps shown as below:

1. Please wipe the dust from the instrument and probe surface with a soft cloth. Do

not make any scuffing on the transparent LCD protection screen when clean the
LCD screen.

2. Clean the instrument with a wet soft cloth not dripping water, during the period

of which please pay attention to the disconnection of power. It is recommended to
scrub with soft detergent or fresh water. Please don't apply any corrosive
chemical cleaning agent to prevent the instrument or probe from damage.

Warning : Before power on again for operation, it is required to confirm that

the instrument has already been dried completely, avoiding any electrical short circuit
or bodily injury resulting form the moisture.