GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
CONTENTS PAGE
1. PRODUCT INTRODUCTION.................. .......... ........... .........
1-1.Description……………………………………………….
1-2.Feature…………………………………………………...
1
1
2
2. TECHNICAL SPECIFICATION………………………….. 4
3. PRECAUTIONS BEFORE OPERATION…….…………..
3-1.Unpacking the instrument………………….…………..
3-2.Checking the Line Voltage…………………..………….
3-3.Environment……………………………………..………
3-4.Equipment Installation and Operation………………....
3-5.CRT Intensity……………………………………………
3-6.Withstanding Voltage of Input Terminals……………...
7
7
7
8
8
8
8
4. PANEL INTRODUCTION……………………..…………..
4-1.Front Panel……………………………………………….
4-2.Rear Panel……………………………………….………
9
11
30
5. OPERATION METHOD………………………………...…
5-1.Readout Display……………………………………..…...
5-2.Connecting Input Signals..………………………………
5-3.Adjustment and Checks…………………………………
5-4.Function Check…..………………………………………
5-5.Basic Operation………….….…………………………...
5-6.Measurement Application……………………………….
32
32
34
35
37
39
47
6. MAINTENANCE……………………………………………
6-1.Fuse Replacement………………………………………..
6-2.Line Voltage…………………………………………..….
6-3.Cleaning………………………………………………….
51
51
51
52
7. BLOCK DIAGRAM………………………………………... 53
USER MANUAL
SAFETY TERMS AND SYMBOLS
These terms may appear in this manual or on the product:
WARNING. Warning statements identify condition or
practices that could result in injury or loss of life.
CAUTION. Caution statements identify conditions or
practices that could result in damage to this product or
other property.
The following symbols may appear in this manual or on the product:
DANGER ATTENTION Protective Earth(ground)
High Voltage refer to Manual Conductor Terminal
Terminal
i
ii
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
FOR UNITED KINGDOM ONLY
NOTE: This lead/appliance must only be wired by competent persons
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT: The wires in this lead are coloured in accordance with
the following code:
Green/ Yellow: Earth
Blue: Neutral
Brown: Live (Phase)
As the colours of the wires in main leads may not correspond with the
colours marking identified in your plug/appliance, proceed as follows:
USER MANUAL
This cable/appliance should be protected by a suitably rated and
approved HBC mains fuse: refer to the rating information on the
equipment and/or user instructions for details. As a guide, cable of
0.75mm
2
should be protected by a 3A or 5A fuse. Larger conductors
would normally require 13A types, depending on the connection
method used.
Any moulded mains connector that requires removal /replacement
must be destroyed by removal of any fuse & fuse carrier and disposed
of immediately, as a plug with bared wires is hazardous if a engaged
in live socket. Any re-wiring must be carried out in accordance with
the information detailed on this label.
The wire which is coloured Green & Yellow must be connected to the
Earth terminal marked with the letter E or by the earth symbol
or coloured Green or Green & Yellow.
The wire which is coloured Blue must be connected to the terminal
which is marked with the letter N or coloured Blue or Black.
The wire which is coloured Brown must be connected to the terminal
marked with the letter L or P or coloured Brown or Red.
If in doubt, consult the instructions provided with the equipment or
contact the supplier.
iii
iv
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
EC Declaration of Conformity
We
GOOD WILL INSTRUMENT CO., LTD.
No. 7-1, Jhongsing Rd., Tucheng City, Taipei County 236, Taiwan
GOOD WILL INSTRUMENT (SUZHOU) CO., LTD.
No. 69 Lushan Road, Suzhou New District Jiangsu, China.
declares that the below mentioned product
GOS-6112
is herewith confirmed to comply with the requirements set out in the Council
Directive on the Approximation of the Law of Member States relating to
Electromagnetic Compatibility (89/336/EEC, 92/31/EEC, 93/68/EEC) and Low
Voltage Equipment Directive (73/23/EEC).
For the evaluation regarding the Electromagnetic Compatibility and Low Voltage
Equipment Directive, the following standards were applied:
EN 61326-1: Electrical equipment for measurement, control and laboratory
Conducted and Radiated Emissions
EN 55011 class B: 1991
EN 55022 class B: 1994
Current Harmonic
EN 61000-3-2: 1995
Voltage Fluctuation
EN 61000-3-3: 1995
Surge Immunity
Conducted Susceptibility
Power Frequency Magnetic fie ld
Voltage Dips/ Interrupts
Low Voltage Equipment Directive 73/23/EEC & amended by 93/68/EEC
Safety Requirements
EN 61010-1: 1990+A1: 1992+A2: 1995
IEC 61010-1: 1990+A1: 1992+A2: 1995
use –– EMC requirements (1997+A1: 1998)
Electrostatic Discharge
EN 61000-4-2: 1994
Radiated Immunity
ENV 50140: 1993
Electrical Fast Transients
EN 61000-4-4: 1995
EN 61000-4-5: 1995
EN 61000-4-6: 1996
EN 61000-4-8: 1993
EN 61000-4-11: 1994
USER MANUAL
1.PRODUCT INTRODUCTION
1-1. Description
The GOS-6112 is a 100MHz, two-channel, dual-sweep, portable oscilloscope
for general purpose use. A microprocessor-based operating system controls
most of the functions of the instrument, including cursor readout and
digitized panel setting. On-sc reen alphanumeric readout and cursor fu nction
for voltage, time, frequency and phase measurement provide extraordinary
operational convenience.
The vertical deflection system has two input channels. Each channel has 11
basic deflection factors from 2mV to 5V per division. The horizontal
deflection system provides single, dual or delayed sweeps from 0.5s to 50ns
per division (delayed sweep, 50ms to 50ns per division). The trigger system
provides stable triggering over the full bandwidth of the vertical deflection
system.
v
1
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
1-2.Features
Additionally, the oscilloscope offers several other features:
1) High intensity and internal graticule CRT
The oscilloscope employs a high intensity 6-inch retangular type
cathode-ray tube with red internal graticule. It display s clear readable
traces even at high sweep speeds. Internal graticule lines eliminate
parallax-viewing error between the trace and the grat icule line .
2) Temperature compensation
The oscilloscope uses a temperature compensation circuit to reduce the
drift of base line and DC balance.
3) 20MHz bandwidth limit
When it is hard to observe or trigger a signal because a high-frequency
component is superimposed on the signal, use the 20MHz BWL
function to reduce the bandwidth of the vertical deflection system and
trigger system to 20MHz.
4) TV triggering
Exclusive TV sync separator circuit technology provides stable TV
signal measurements on fields, frames and lines.
5) Z-axis intensity modulation
For applying a blanking signal from an external source. The trace
displayed on the screen may be intensity-modulated where pulse signal
or time-scale marks are required.
USER MANUAL
6) Trigger signal output
The signal selected by the TRIGGER SOURCE is available. This
output may be used to connect to a frequency counter or other
instrument.
7) Panel setups lock
To avoid unintentional touch of the setting, the feature is extremely
useful for long term and repetitive measurements that used to be
performed under the same test condition of the oscilloscope setting.
8) LED indicator and buzzer alarm
The LED’s located in the front panel assist operation and indicated
additional information. Incorrect operation and the electrical end
position of control knobs are indicated by a warning beep.
9) SMD manufacturing technology
The instrument is built by using the most advanced SMD technology
so as to reduce the number of internal wiring and shorten the foil rout e
on the pc board. This will also greatly increase the high frequency
performance and the reliability of the product.
2
3
GOS-6112 OSCILLOSCOPE
USER MANUAL
2.TECHNICAL SPECIFICATIONS
Sensitivity 2mV~5V/DIV,11 step in 1-2-5 sequence
VERTICAL
DEFLECTION
SYSTEM
TRIGGER
SYSTEM
Sensitivity Accuracy
Vernier Vertical Sensitivity
Frequency Bandwidth(-3dB) DC ~ 100MHz (2mV/DIV:DC ~ 20MHz)
Rise Time 3.5ns (2mV/DIV:17.5ns)
Signal Delay Leading edge can be monitored
Maximum Input Voltage 400V (DC+AC) at 1kHz or less
Input Coupling AC, DC, GND
Input Impedance
Vertical Modes
CHOP Repetition Frequency Approx. 250kHz.
Polarity (INV) CH2 only
Bandwidth Limit ed 20MHz
Common-mode
Rejection Ration
Dynamic Range 8 div at 60MHz, 5 div at 100MHz.
Trigger Modes AUTO, NORM, TV
Trigger Source CH1, CH2, LINE, EXT
Trigger Coupling AC, DC, HFR, LFR
Trigger Slope +/- polarity or TV sync polarity
Trigger Sensitivity
Trigger Level Range
TV Sync TV-V,TV-H
Max. External Input Voltage 400V (DC + AC peak) at 1k Hz
External Input Impedance
±3% (5 DIV at the center display )
Continuously variable to 1/2.5 or less than
panel-indicated value
1MΩ±2% // 25pF approx.
CH1,CH2,DUAL(CHOP/ALT),ADD(DIFF mode can
be established when the CH2 is in the INV mode)
50:1 or better at 50kHz
Mode Frequency INT EXT
AUTO
TV Sync signal 1DIV 200mVpp
INT : ± 4 DIV or more
EXT : ± 0.4 V or more
1MΩ± 5% ∕∕ 25pF approx.
10Hz~20MHz 0.35DIV 50mVpp
20MHz~100MHz 1.5DIV 150mVpp
DC~20MHz 0.35DIV 50mVppNORM
20MHz~100MHz 1.5DIV 150mVpp
4
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
HORIZONTAL
DEFLECTION
SYSTEM
X-Y
OPERATION
CURSOR
READOUT
FUNCTION
CRT
Z-AXIS
INPUT
USER MANUAL
Horizontal Modes MAIN(A), ALT, DELAY(B)
A (main) Sweep Time
B (delay) Sweep Time 50nS~50mS/DIV
Accuracy ± 3% (± 5% at × 10 MAG)
Sweep Magnification × 10 (maximum sweep time 5nS/DIV)
Hold Off time Variable
Delay Time 1uS~5S
Delay Jitter 1/20000 or less
Alternate Separation Variable
Sensitivity Accuracy
X-axis Bandwidth DC~500kHz (-3dB)
Phase Error
Cursor Measurement Function
Cursor Resolution 1/100 DIV
Effective Cursor Range Vertical: ± 3 DIV; horizontal: ± 4 DIV
Panel setting
Type
Phosphor P31
Accelerating Potential 12kV approx.
External intensity modulation
Coupling DC
Voltage 5V or more
Maximum Input Voltage 30V (DC+AC peak) at 1kHz or less
Bandwidth DC~5MHz
50nS~0.5S/DIV, continuously variable
(UNCAL)
X-axis, Y-axis selectable
X-axis: CH1, CH2Æ 2mV~5V/DIV ± 3%
EXT Æ 0.1V/DIV ± 5%
Y-axis: CH1,CH2Æ 2mV~5V/DIV ± 3%
3°or less at DC~50kHz
ΔV,ΔV%,ΔVdB,ΔT,1/ΔT,ΔT%,Δ
Vertical: V/DIV (CH1,CH2),UNCAL, ADD,
INV, P10, AC/DC/GND.
Horizontal: S/DIV (MTB, DTB), UNCAL
x 10MAG, Delay time, Hold-off.
Trigger: Source, Coupling, Slope, Level ,
TV-V/TV-H.
Others: X-Y, LOCK.
6-inch rectangular type with internal graticule
0%, 10%, 90% and 100% markers.
8 x 10 DIV (1 DIV = 1 cm)
Θ
.
TRIGGER
SIGNAL
OUTPUT
CALIBRATOR
OUTPUT
SPECIAL
FUNCTION
LINE POWER
REQUIREMENT
OPERATING
ENVIRONMENT
STORAGE
TEMPERATURE
& HUMIDITY
MECHANICAL
SPECIFICATION
ACCESSORIES
USER MANUAL
Voltage
Frequency Response DC~10MHz
Output Impedance
Waveform 1kHz ± 5%, square wave
Voltage 2Vpp ± 2%
Impedance
Panel Setups Lock Provided
Voltage
Frequency 50Hz or 60Hz
Power Consumption Approx. 90VA, 70W(max.)
Indoor use
Altitude up to 2000 m
Ambient temperature :
To satisfy specifications : 10° to 35℃ ( 50° to 95°F )
Maximum operating ranges: 0° to 40℃( 32 °to 104°F )
Relative humidity:85% RH(max.) non condensing
Installation Category II
Pollution degree 2
-10° to 70℃, 70%RH(maximum)
Dimensions 310 W × 150 H × 455 D (mm)
Weight Approx. 9kgs (19.8 lbs)
Power cord….............……….. 1
Instruction manual…………… 1
Probe (×1/×10)…………..… 2
25mV/DIV approx. in 50Ω termination
50Ω approx.
2kΩ approx.
AC 100V, 120V, 230V ± 10% selectable
5
6
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
3.PRECAUTIONS BEFORE OPERATION
3-1.Unpacking the Oscilloscope
The product has been fully inspected and tested before shipping from the
factory. Upon receiving the instrument, please unpack and inspect it to
check if there is any damages caused during transportation. If any sign of
damage is found, notify the bearer and/or the dealer immediately.
3-2.Checking the Line Voltage
The oscilloscope can be applied any kind of line voltage shown in the
table below. Before connecting the power plug to an AC line outlet, make
sure the voltage selector of the rear panel is set to the correct position
corresponding to the line voltage. It might be damaged the instrument if
connected to the wrong AC line voltage.
WARNING. To avoid electrical shock the power cord
protective grounding conductor must be connected to
ground.
When line voltages are changed, replace the required fuses shown as below:
Line voltage Range
100V
120V
108-132V
WARNING. To avoid personal injury, disconnect the power
Fuse Line voltage Range
90-110V
cord before removing the fuse holder.
T 1A 250V 230V 207-250V T 0.4A 250V
Fuse
USER MANUAL
3-3.Environment
The normal ambient temperature range of this instrument is from 0° to
40°C (32° to 104°F). To operate the instrument over this specific
temperature range may cause damage to the circuits.
Do not use the instrument in a place where strong magnetic or electric
field exists as it may disturb the measurement.
3-4.Equipment Installation, and Operation
Ensure there is proper ventilation for the vents in the oscilloscope case. If
this equipment is used not according to the specification, the protection
provided by the equipment may be impaired.
3-5.CRT Intensity
To prevent permanent damage to the CRT phosphor, do not make the
CRT trace brighten excessively or leave the spot stay for an unreasonably
long time.
3-6.Withstanding Voltages of Input Terminals
The withstanding voltages of the instrument input terminals and probe
Input terminals are shown in the following table. Do not apply voltages
higher than these limits.
Input terminal Maximum input voltage
CH1, CH2, inputs 400V (DC + AC peak)
EXT TRIG input 400V (DC + AC peak)
Probe inputs 600V (DC + AC peak)
Z AXIS input 30V (DC + AC peak)
CAUTION. To avoid instrument damage, do not apply exceeding
maximum input voltage of 1 kHz the frequency to the instrument.
7
8
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
4. PANEL INTRODUCTION
After the instrument is switched on, all the important settings are displayed
in the readout. The LED’s located on the front panel assist operation and
indicate additional information. Incorrect operation and the electrical end
positions of control knobs are indicated by a warning beep.
Except the Power pushbutton (POWER), the Focus control (FOCUS), and
the Trace Rotation control, all other controls are electronically selected,
and their functions and sett ings can t herefor e be store d.
The front panel is subdivided into six sections:
z Display controls
z Vertical controls
z Horizontal controls
z Trigger controls
z Measurement control
z Input connectors
USER MANUAL
Front panel of GOS-6112
9
10
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
4-1.Front Panel
Display controls
The display controls adjust the on-screen appearance of the waveform and
provide a probe compensation signal source.
FOCUS
CAL
2Vp-p
1 KHz
5
ROTATION
4 3
TRACE INTEN
OFF
(1).POWER – Pushbutton and symbols for ON(1) and OFF(0).
When switch on the oscilloscope to have all LEDs lighted and the
software version will be displayed on the screen. After the Internal test
is completed successfully, the normal operation mode is present. Then
the last settings become activated and the LED indicates the ON
condition.
(2).INTEN – TRACE/READOUT – Control knob with associated
pushbutton and readout display.
The control knob is used for adjusting the traces and readout intensity.
Turning the knob clockwise to increase the intensity and turning it
counterclockwise to decrease the intensity.
The TRACE/READOUT pushbutton is for selecting the intensity
function and indicates the letter “TRACE INTEN” or “READOUT
INTEN” in the readout. Press the pushbutton briefly for the following
sequences:
“TRACE INTEN” — “READOUT INTEO” — “TRACE INTEN”
TRACE/
POWER
READOUT
21
USER MANUAL
(3).TRACE ROTATION
The TRACE ROTATION is for aligning the horizontal trace in
parallel with graticule lines. This potentiometer can be adjusted with a
small screwdriver.
(4).FOCUS
The control knob effects both the trace and the readout sharply.
(5).CAL
The terminal provides a reference signal of 2Vp-p at 1kHz for probe adjustment.
Vertical controls
The vertical controls select the displayed signals and control the
amplitude characteristics.
910
VERTICAL
13
15
POSITION
C1
8
20MHz
7
AC/DC
CURSOR
BWL POS
V1/2
VOLTS/DIV
2mV
5V
CH1
VAR
GND
Px10
17 19 18 20
C2
ALT/
CHOP/
ADD
5V
AC/DC
POSITION
INV
VOLTS/DIV
VAR
Px10
TRACE
2mV
CH2
GND
SEP
11
12
14
16
11
12
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
(7).20MHz BWL – Pushbutton with indicator LED.
Briefly pressing the pushbutton, the bandwidth is reduced to approx.
20MHz, and the measurement is made by eliminating undesired high
frequency signal from the waveform. Also the high frequency
component over 20MHz is eliminated from the trigger signal.
(8).CURSOR POS - △V1/2 — Pushbutton with double function and
associated indicator LED.
The function of Cursor Position or CH1/CH2 Position can be selected
only after the pushbutton of Cursor Function is pressed to appear
enabling their cursor measurement. Press the pushbutton once briefly
to have the related LED lighted, the CH1/CH2 POSITION control
knob is then operated as CURSOR 1/CURSOR 2 POSITION control.
△V1/2
The function is required and available only in DUAL mode in
combination with △V (Voltage) measurement. Pressing and holding
the pushbutton, then switch between CH1 and CH2, the measured
result will be displayed by the readout with “△V1…” or “△V2… ”
providing the defection coefficient is calibrated. The settings of the
cursors must be related to the signal of the selected channel.
(9).CH1 POSITION – C1 — Control knob with double function.
The vertical trace position of channel 1 can be set with the control knob,
which is also operated as CURSOR 1 position control in cursor
measurement mode.
(10)CH2 POSITION – C2 — Control knob has several functions.
The vertical trace position of channel 2 can be set with the cont rol
knob, which is also operated as CURSOR 2 position control in cursor
measurement mode. In alternate time base mode, this control knob
can be used to separate the DELAY time base trace from the MIAN
time base trace. Please note TRACE SEP (11).
(11)TRACE SEP
The instrument contains a trace separate function which is required in
the alternate time base mode to separate the DELAY time ba se trace(s)
from the MAIN time base in vertical direction. Consequently this
function is only available in alternate time base mode. Press the
pushbutton once to have the related LED lighted, the CH1 POSITION
control knob is then operated as vertical position control for the
trace(s) of the DELAY time base.
(12)ALT/CHOP/ADD-INV
The pushbutton has sever al function s, which are requ ired and avail able
only when both channels are active.
ALT– Displays in the readout, indicates alternate channel switching.
After each time base sweeps the instrument internally, switches over
from channel 1 and channel 2 and vi ce versa.
CHOP– Indicates chopper mode.
The channel switching occurs constantly between channel 1 and
channel 2 during each sweep.
ADD– Displays in the readout, indicates additional mode.
Whether the algebraic sum (addition) or the difference (subtraction) of
both input signals is displayed, depends on the phase relationship and
the INV setting. As a result, both signals are displayed as one signal.
For correct measurements, the deflection coefficients for both channels
must be equal.
INV—Pressing and holding the pushbutton to set the channel 2 invert
function on or off. The invert on condition is indicated with a horizontal
bar above “CH2” in the readout. The invert function causes the signal
display of channel 2 to be inver ted by 180
USER MANUAL
o
.
13
14
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
(13)CH1 VOLTS/DIV.
(14)CH2 VOLTS/DIV– Control knob for channel 1/channel 2 has double
function.
Turning the knob clockwise to increase the sensitivity in 1-2-5 sequence
and turning it in the opposite direction (CCW) to decrease. The
available range is from 2mV/div up to 5V/div. The knob is
automatically switched inactive if the relate d channe l is switched off.
The deflection coefficients and additional information regarding the
active channels are displayed in the readout.
ie. “CH1=deflection coefficient, input coupling”. The “=” symbolizes
calibrated measuring conditions and is replaced by the “>” symbol in
uncalibrated conditions.
(15)CH1-VAR.
(16)CH2-VAR — Pushbutton with double function.
CH1/CH2
Pressing briefly the CH1(CH2) button to set the cannel 1 (channel 2) of
the instrument on, the deflection coefficient will be displayed in the
readout indicating the current conditions (“CH1…”/ “CH2…”).
VAR
Pressing and holding the pushbutton to select the VOLTS/DIV function
between attenuator and vernier (variable). The current setting is
displayed by the “>” symbol in the readout.
After switching on the VAR, turn the VOLTS/DIV control knob
counterclockwise to reduce the signal height, and the deflection
coefficient becomes uncalibrated.
USER MANUAL
(17)CH1 AC/DC.
(18)CH2 AC/DC
Pressing the pushbutton briefly to switch over from AC (~ symbol) to
DC (= symbol) input coupling. The setting is displayed in the readout
with the deflection coefficient.
(19)CH1 GND– P×10
(20)CH2 GND – P×10 –Pushbutton has two functions.
GND
Each time when the pushbutton is pressed briefly, the input of the
vertical amplifier is grounded. It is displayed in the readout as an earth
(ground) symbol “ ”.
P×10
Pressing and holding the pushbutton to select the indicated deflection
coefficient of the channel displa yed in the read out betwee n 1:1 and 10:1.
The probe factor of 10:1 is displayed in the readout with the probe
symbol in front of channel indicat ion (e.g. “P10”, CH1) When proceed
cursor voltage measurement, the probe factor will be automatically
included. The symbol must not be activated unless a 10:1 attenuator
probes are used.
15
16
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
Horizontal controls:
The horizontal controls select the time base operation mode and adjust the
horizontal scale, position and magnification of the signal.
HORIZONTAL
POSITION
23
22
21
(21)TIME/DIV– Control knob with double function.
Turning the knob clockwise to reduce the deflection coefficient in a
1-2-5 sequence and turning it in the opposite direction (CCW) to
increase. The time coefficient(s) will be displayed in the readout.
In MAIN time base (MTB) mode, time deflection coefficients between
0.5s/div and 50ns/div can be chosen in 1-2-5 sequence, if the ×10
MAG function is not activated.
During alternate (ALT) and DELAY time base (DTB) operation, the
control knob changes the DELAY time base setting in 1-2-5 sequence.
The available deflection coefficient range is from 50ms/div up to
50ns/div (without ×10 MAG), but the availability depends on the
MAIN time base setting. The internal control of the oscilloscope
prevents the DELAY time deflection coefficient from becoming higher
than the MAIN deflection coefficient, as such an operation condition
would make no sense.
MAIN/
ALT /
DELAY
X-Y
TIME/DIV
0.5S
SETUPS
LOCK
VAR
50nS
x10
MAG
24
25
USER MANUAL
(22)MAIN/ALT/DELAY—X-Y – Pushbutton for time base mode
selection.
The instrument contains two-time base designated MAIN and DELAY.
With the aid of the DELAY time base, signal parts displayed by the
MAIN time base can be expanded in X-direction. The expansion ratio
depends on the time deflection coefficient ratio of both time bases (ie.
“MTB=0.1ms”, “DTB=1μs”=100). With higher expansion ratio the
DELAY time base trace intensity reduces. Each time when press the
pushbutton briefly, the time base mode changes in the sequence of
MAIN-ALT-DELAY-MAIN. The actual setting is displayed in the
readout.
MAIN
The TIME/DIV control knob is operated only under the MAIN time
base mode. The readout then displays the main time coefficient alone.
The time base setting for this condition will be stored if the time base
mode is changed.
ALT
If the alternate time base mode is selected, the TIME/DIV knob only
controls the DELAY time base switch. The alternate ti me base mode is
a sub-function of the DELAY time base mode and both time base
traces can be displayed simultaneously. Consequently the readout can
display both time deflection coefficient. A window sector which
indicates part of signal is also visible on the MAIN trace and is
displayed by the DELAY time base.
The window segment can be shifted horizontally by the DELAY TIME
control continuously. The difference between the beginning of both the
MAIN time base trace and the window sector shows the delay time.
The information is also displayed in the readout with an approximate
value (e.g. “DLY=0.125ns”) related to the calibrated MAIN time
17
18
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
coefficient (uncalibrated i.e. “DLY>0.125ms”). The width of the
window segment decreases when the DELAY time coefficient is set to
a lower value (higher time deflection speed).
For better reading, the vertical position of the DELAY time base trace
position can be shifted (please note TRACE SEP (11)).
DELAY
In the DELAY time base mode, the display of the MAIN traces, the
window sector and the MAIN time coefficient will disappear from the
readout. As the trace separation is no longer required under the
circumstances, the functio n would be switched off too. Consequently ,
only the DELAY time coefficient is displayed by the readout.
X-Y
Switch on or off the X-Y mode by pressing and holding the button. In
the X-Y mode, the deflection coefficient is displayed in the readout.
The Y axis input is selected by setting the vertical mode pushbutton to
the CH1, CH2 and both modes, and the X axis input is selected by
setting the TRIGGER SOURCE pushbutt on to the CH1, CH2 and EXT.
(23)H POSITION
The control knob enables a horizontal position shift of the signals. In
combination with ×10 MAG the function makes it possible to shift any
part of the signal on the screen.
(24)×10 MAG—SETUPS LOCK— Pushbutton has double function and
associated MAG LED.
Each time when this pushbutton is pressed, the MAG LED located
above will be switch on or off. If the MAG LED is lighted, the signal
display in all time base modes will be expanded 10 folds and
consequently only a tenth part of the signal curve is visible. The
interesting part of the signal can be made visible with the aid of the H.
POSITION control.
USER MANUAL
SETUPS LOCK
Pressing and holding the pushbutton, then switch the panel setups lock
function on or off. To avoid unintentional touch of the setting, the
feature is extremely useful for long term and repetitive measurements
that need to be performed under the same test condition of the
oscilloscope setting.
(25)VAR
Pressing and holding the pushbutton to select the TIME/DIV (21)
control knob function between time base switch and vernier (variable).
The variable function is activated in the MAIN time base only.
After switching on the VAR, the time deflection coefficient is still
calibrated until further adjustments are made. Turn the TIME/DIV (21)
control knob counter clockwise to increase the time deflection
coefficient (reduce the deflection speed) and the deflection coefficient
becomes uncalibrated. Instead of “A=10μs”, the readout then displays
“A>10μs” indicating the uncalibrated condition. This setting is stored
if the instrument is switched to ALT or DELAY time base mode.
Switch off the VAR by pressing and holding the pushbutton of time
base mode again, then set the time deflection coefficient back into the
calibrated condition.
19
20
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
Trigger controls
The trigger controls determine the sweep start timing for both si gnal and
dual trace operation.
TRIGGER
LEVEL
27
26
(26)MODE – Pushbutton and indicator LEDs.
Pressing the pushbutton to select the trigger mode. The actual setting
is indicated by a LED.
Each time when the MODE pushbutton is pressed the trigger mode
changes in the sequence:
ATO—NML—TV—ATO
ATO (Auto)
Select the automatical mode, the sweep free-runs will display a
baseline trace when there is no trigger signal or the frequency is below
10Hz. The setting of triggering level changed only when the TRIGGER
LEVEL control is adjusted to a new level setting.
-
+
SOURCE
MODE
ATO
NML
TV
SLOPE
DELAY TIME
CH1
CH2
EXT
HO
COUPLING
32 31
AC
DC
HFR
LFR
TV-V/
TV-H
28
29
30
USER MANUAL
NML (Normal)
Select the normal mode, the input signal will trigger the sweep when
the TRIGGER LEVEL control is set within the peak-to-peak limits of
an adequate trigger signal. When the sweep is not triggered, no
baseline trace will be displayed.
TV
Separate the video sync signal from the composite waveform and
direct it to the triggering circuit. The horizontal or vertical sync signals
are selected by TV-V/TV-H pushbutton. Please refer to the
TV-V/TV-H (31).
(27)LEVEL—Control knob
Turning the control knob causes a different trigger input setting
(voltage), and set to a suitable position for the starting of triggered
sweep of the waveform. An approximate trigger level setting (voltage)
value will be displayed in the readout. When rotate clockwise the
control knob, the trigger point moves toward the positive peak of the
trigger signal and rotate it counterclockwise to move the trigger point
toward the negative peak of the trigger signal.
When the setting (voltage) value is out of the changing portion of the
observation waveform, the synchronization sweep stops. Sometimes a
“?” will be displayed on the left of the valued display, that indicates
that direct reading is impossible if AC, HFR, LFR coupling or VAR of
vertical deflection is set.
21
22
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
(28)COUPLING –Pushbutton and indicator LEDs.
Pressing the pushbutton to select the trigger coupling. The actual
setting is indicated by a LED and by the readout (“source, slope, AC”).
Each time when the COUPLING pushbutton is pressed the trigger
coupling changes in the sequence:
AC—DC—HFR—LFR
AC
Attenuates trigger signal frequency components below 10Hz and
blocks the DC component of the signal.
AC coupling is useful for triggering on AC waveforms that have a
large DC offset.
DC
Couples DC and all frequency components of a triggering signal to the
trigger circuitry.
DC coupling is useful for most signals, especially for providing a
stable display of low-frequency or low-repetition-rate signals.
HFR (High Frequency Reject)
Attenuates high-frequency triggering signal components above 40kHz.
HFR coupling is useful for providing a stable display of low-frequency
components of complex waveforms and eliminates high-frequency
interference from the trigger signal.
USER MANUAL
(29)SOURCE—Pushbutton and associated LEDs.
Pressing the pushbutton to select the trigger signal source or the X
signal for an X-Y operation. The actual setting is indicated in a LED
and by the readout (“SOURCE”, slope, coupling).
CH1
The signal applied to the channel 1 input connector is the source of
the trigger signal.
CH2
The signal applied to the channel 2 input connector is the source of
the trigger signal.
(Line)
The triggering signal is obtained from a sample of the AC power
source waveform. The trigger source is useful when the displayed
waveform frequency is time related to the AC power source
frequency.
EXT
The external signal applied through the EXT input connector is used
for the external triggering source signal. When in the dual X-Y
operation, the X-axis operates with the external signal.
LFR (Low Frequency Reject)
Attenuates low-frequency triggering signal components below 40kHz
and blocks the DC component of the trigger signal.
LFR coupling is useful for producing stable triggering on the
high-frequency components of complex waveforms and rejecting
low-frequency interference or power supply hum from the trigger
signal.
23
24
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
(30)DELAY-HO—Control knob with a double function and associated
LED.
The control knob has two different functions depending on the time
base mode.
HO (Hold-off time)
In MAIN time base mode, the control knob applies to the hold off
time setting, the HO-LED associated with the knob is dark, th e hold
off time is set to minimum.
Switch on the LED by turning the control knob clockwise and extend
the hold off time until the maximum is reached. An approxi mate hold
off time value will be displayed in the readout (“HO: %”).
The hold off time is automatically set to minimum (LED is dark), i f
the MAIN time base setting is changed. The hold off time setting is
stored and deactivated if ALT (MAIN and DELAY) or DELAY time
base mode is selected.
DELAY TIME
In ALT (MAIN and DELAY) and DELAY time mode, the knob
controls the delay time setting.
Under the ALT time base mode, the delay time is visi ble on the main
trace, beginning at the trace start and ending at the start of the
window sector. An approximate delay time value will be displayed in
the readout (“DLY=”).
If only select DELAY time base, the delay time can also be varied,
but there would be no window sector as the main trace is not visible.
USER MANUAL
(31)TV-V/TV-H—Pushbutton for video sync signal selection.
TV-V
Start the main trace at the beginni ng of a video signal field. SLOPE
polarity must match the composite sync polarity (i.e, “–” for negative
sync) to obtain TV field triggering on the vertical sync pulse.
TV-H
Start the main trace at the beginning of a video signal line. SLOPE
polarity must match the composite sync polarity to obtain TV line
triggering on the horizontal sync pulse.
The current setting is displayed in the readout under item “source,
video polarity, TV-H”.
(32)SLOPE ( )—Pushbutton for the triggering slope or video
polarity selection.
If in the AUTO or NML trigger mode, briefly pressing the pushbutton
to select the slope of the signal which is used for triggering the time
base generator. Each time when the pushbutton is briefly pressed, the
slope direction will switch fro m falling edge to rising edge, and vice
versa.
The current setting is displayed in the readout under item “source,
SLOPE, coupling”.
If in the TV trigger mode, briefly pressing the pushbutton to select the
video polarity, which will be displayed in the readout with a “+”
symbol of positive video signal and a “–” symbol of negative video
signal.
25
26
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
Measurement and Panel setting Control
The measurement section controls the on-screen readout and the cursor
measurements.
CURSOR
FUNCTION
ON/OFF
33
(33)CURSOR FUNCTION-ON/OFF—Pushbutton with two functions.
ON/OFF
Pressing and holding either pushbutton to switch both cursor lines on
or off. As the cursor lines are part of the rea dout, they are vi sible only
when the readout is switched on.
CURSOR FUNCTION
Each time when the pushbutton is briefly pressed the seven
measurement functions will be selected in the sequence as below:
△V : Voltage difference measurement.
△V% : Voltage difference percentage measurement
(5div=100% reference)
△VdB : Voltage gain measurement.
(5div=odB reference, △VdB=20 log, div/5div).
△T : Time difference measurement.
1/△T : Frequency measurement.
△T% : Time difference percentage measurement.
(5div=100% reference).
△θ : Phase measurement.
(5div=350
o
reference).
USER MANUAL
Input connectors
The input section is where the input signals are commonly connected to
the oscilloscope.
(35)CH1—Input BNC socket
This BNC socket is the signal input for channel 1. In X-Y mode,
signals at this input are used for the Y or X deflection. The outer
(ground) connection is galvanically connected to the instrument
ground and consequently to the safety earth contact of the line/mains
plug.
(36)CH2—Input BNC socket
This BNC socket is the signal input for channel 2. In X-Y mode,
signals at this input are used for the X or Y deflection. The outer
(ground) connection is galvanically connected to the instrument
ground and consequently to the safety earth contact of the line/mains
plug.
(37)Ground socket—Banana Socket galvanically connected to safety
earth.
This socket can be used a reference potential connection for DC and
low frequency signal measurement purposes.
27
28
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
(38)EXT—This BNC socket is the external trigger signal input.
In dual X-Y mode, signals at this input are used for the X deflection.
Pressing the TRIG. SOURCE (29) pushbutton until the information of
“EXT, slope, coupling” is shown up in the readout and the TRIG.
SOURCE “EXT” LED is lighted, switches the input on.
The outer (ground) connection is galvanically connected to the
instrument ground and consequently to the safety earth contact of the
line/mains plug.
The maximum input voltages of the instrument input terminals and probe
input terminals are listed in the section of 3-6.Withstanding voltage of
Input terminals”. Do not apply voltage higher than the limit.
USER MANUAL
4-2.Rear Panel
The rear panel provides input power and additional signal connections.
WARNING
TO AVOID ELECTRIC SHOCK THE POWER CORD PROTECTIVE GROUNDING
CONDUCTOR MUST BE CONNECTED TO GROUND.
FOR CONTINUED FIRE PROTECTION. REPLACE ONLY WITH SPECIFIED
TYPE AND RATED FUSE.
NO OPERATOR SERVICEABLE COMPONENTS INSIDE. DO NOT REMOVE
QUALIFIED PERSONNEL.
COVERS. REFER SERVICING TO
(39)Line voltage selector and input fuse holder—Select power source
and contain the primary power fuse
The fuse rating is shown in the section of 3-2 Checking the line
voltage.
(40)AC power input connector
Connect the AC power cord to the power supply of instrument, the
power cord protective-ground connection is connected to the exposed
metal part of the instrument. The power cord must be connected to a
proper grounded source for electrical-shock protection.
(41)TRIGGER SIGNAL Output—BNC socket
The signal selected by the TRIG. SOURCE (29) is available. This
output may be used to connect to a frequency counter or other
instrument.
120
100
230
ENSURE THE POWER IS REMOVED FROM
THE INSTRUMENT BEFORE REPLACING THE FUSE
RANGE
LINE VOLTAGE
SELECTION
(50/60Hz)
90~110V
110V
108~132V
120V
207~250V
230V
POWER MAX. 70 WATTS, 90VA
IEC1010 250V CAT
39
AC
TRIGGER SIGNAL Z-AXIS
OUTPUT
INPUT
INTO 50
30Vpk MAX.
W
CAT
25mV/DIV
FUSE
T 1A
250V
T 0.4A
250V
40
41 42
29
30
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
(42)Z-Axis Input—BNC socket
Connect external signals to the Z-axis amplifier for intensity
modulating the CRT display. This terminal is DC-coupled. The
intensity is lowered by a positive signal, while it is increased by a
negative signal.
USER MANUAL
USER MANUAL
5. OPERATION METHOD
This section contains basic operation information and techniques that
should be considered before proceeding any measurement. As for the
location and function of instrument controls, connectors, and indicators,
refer to the “Instruction of Front Panel and Rear Panel” of this manual.
5-1.Readout Display
The CRT readout display indicates how to set up the instrument controls.
No physical marking shown on the r otating switches indicates the control
setting. A key to the location and type of readout information displayed is
illustrated in figure 5-1:
31
32
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
USER MANUAL
5-2.Connecting Input Signals
Grounding
The most reliable signal measurements are made when the oscilloscope
and the unit under test are connected by a common reference (ground
lead) in addition to the signal lead or probe. The ground lead of the probe
provides the best grounding method for signal interconnection and
ensures the maximum amount of signal-lead shielding in the probe cable.
A separate ground lead (with a banana plug) can also be connected from
the unit under test to the oscilloscope ground jack on the front panel.
Probes
A probe provides the most convenient way to connect an input signal to
the oscilloscope. The standard ×1/×10 probes supplied to the oscilloscope
are shielded against electromagnetic interference and have a high input
impedance for low circuit loading.
CAUTION. To get the best waveform precisely, keep
probe ground and signal leads as short as possible.
Misadjust probe compensation can cause measurement error. Check and
adjust probe compensation whenever a probe is moved to a different
channel or oscilloscope. As for the probe compensation adjustment
procedure, refer to the “Probe Compensation”.
Coaxial Cables
Signal input cable can greatly affect the accuracy of a displayed
waveform. To maintain original frequency characteristics of the input
signal, use only high-quality, low-loss coaxial cables. Coaxial cables must
be terminated at both ends in their characteristic impedance to prevent
signal reflections within the cable. Use suitable impedance-matching
devices.
33
34
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
5-3.Adjustments and checks
Trace Rotation Adjustment
Normally, when the trace is in parallel with the center horizonta l graticule
line, there will be no need to adjust the TRACE ROTAT ION. If ne cessary,
adjust the TRACE ROTATION to make the baseline trace parallel to the
center horizontal graticule line by using a small straight-blade
screwdriver or alignment tool.
Probe Compensation
To minimize the distortion of measured waveforms, check the
compensation of your probes before using them. The probe compensation
should be checked periodically whenever the probes are moved to
different input channels.
1. Install the probes onto the oscilloscope (Press the BNC connector onto
the channel input and rotate the connector to lock it into place).
2. Set the probe slide switches to the ×10 position.
3. Briefly pressing the CH1/CH2 button to set the oscilloscope to channel
1 and channel 2.
4. Pressing and holding the P×10 button to set the indicated deflection
coefficient of the channel displayed in the readout as a symbol “P10”.
5. Attach the probe tips to the CAL connection in the front of the
oscilloscope.
6. Set the oscilloscope controls to display both channels:
VERTICAL: VOLTS/DIV 1V
COUPLING DC
ALT/CHOP/ADD CHOP
HORIZONTAL: MODE MTB
TIME/DIV 0.5ms
TRIGGER: MODE ATO
SOURCE CH1 or CH2
COUPLING AC
SLOPE
USER MANUAL
7. Observe the displayed waveform and compare them with the
waveforms shown in figure 5-2. If either probe needs to be adjusted,
proceed the step 8. If either probe does not need to be adjusted, proceed
the “Function Check”.
Figure 5-2 Typical Compensation Waveform
8.Adjust the probe by using a small insulated screwdriver. Slowly rotate
the adjustment control until the probe is properly compensated.
35
36
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
5-4.Function Check
When you start to check the operation of your oscilloscope, proceed the
following instruction:
1. Install the ×10 probes onto CH1 and CH2 inputs.
2. Connect the probe tips to the CAL test point of the oscilloscope.
3. Set the oscilloscope controls to display both channels:
VERTICAL: VOLTS/DIV 1V
COUPLING DC
ALT/CHOP/ADD CHOP
HORIZONTAL: MODE MTB
TIME/DIV 0.5ms
TRIGGER: MODE ATO
SOURCE CH1 or CH2
COUPLING AC
SLOPE
The figure 5-3 below illustrates a satisfactory display. The waveform
should be approximately 2Vp-p at a frequency of 1kHz that confirms
the vertical and horizontal deflection function of the oscilloscope.
USER MANUAL
4. Set both CH1 and CH2 COUPLING to GND.
5. Use the CH1 and CH2 POSITION controls to align both traces on the
center graticule.
6. Open the CH2 INV by pressing and holding the pushbutton.
7. Set to the ADD mode by pressing the ALT/CHOP/ADD pushbutton
briefly.
8. Set both CH1 and CH2 COUPLING to DC.
9. The figure 5-4 below shows a satisfactory display. The display will
show a flat trace located on the center gracticule that confirms the
channel balance and ADD offset function.
Figure 5-4 Display 2
10. Set to the CHOP mode by pressing the ALT/CHOP/ADD pushbutton
briefly.
11. Turn off the CH2 INV by pressing and holding the pushbutton.
Figure 5-3 Display 1
37
38
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
5-5.Basic Operation
Displaying CH1 or CH2
To display the signal from a signal channel, pressing briefly the CH1 or
CH2 pushbutton to set the oscilloscope to channel 1 or channel 2.
Displaying CH1 and CH2
To display both signals at the same time, proceed the following steps:
1.Set the CH1 and CH2 on. The figure 5-5 below shows two synchronous
waveforms in the both modes.
2.Adjust the CH1 or CH2 POSITION control to position the two
waveforms.
3.Set the ALT/CHOP/ADD button to CHOP mode if the waveforms are
flickering.
USER MANUAL
Displaying the sum or difference of CH1 and CH2
To display the algebraic sum or dif ference of CH1 and CH2, proc eed the
following steps:
1.Set the ALT/CHOP/ADD button to ADD mode. The figure 5-6 below
shows the sum of the waveforms from figure 5-5.
2.Set the CH2 INV on by pressing an d holding the button, if necessary,
to display the different waveform.
3. Pressing and holding one of the VAR buttons to set the VOLT/DIV
control knob to vernier (variable). Then adjust one channel to the other
in the event of gain difference.
Figure 5-6 Typical ADD waveform
Figure 5-5 Both typical waveforms
39
40
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
Comparing Frequency and phase (Single X-Y Operation)
To compare the frequency and phase between two signals by using the
X-Y mode. The X-Y waveform displays different amplitude, frequency,
and phase. The figure 5-7 shows a typical waveform made up of two
signals that are of the same frequency and amplitude, but approximate
o
45
out of phase.
To use the oscilloscope in the signal of X-Y mode, proceed the following
steps:
1. Connect the horizontal or X-axis signal to the CH1 input.
2. Connect the vertical or Y-axis signal to the CH2 input.
3. Set the CH1 off, and set the CH2 on.
4. Set the X-Y mode on by pressing and holding the button.
5. Set the TRIG SORCE button to CH1.
Use the HORIZONTAL POSITION control to adjust the X-axis.
Note: When high frequency signals are displayed in the X-Y
operation, note the frequency bandwidths and phase difference
between X and Y axis. Refer to “2. SPECIFICATION” section for
details.
USER MANUAL
Setting up Dual X-Y Operation
To use the oscilloscope in the dual X-Y mode, proceed the following steps:
1. Connect the horizontal or X-axis signal to the EXT (X) input.
2. Connect one of the vertical or Y-axis signal to the CH1 (Y1) input.
3. Connect either of the vertical or Y-axis signal to the CH2 (Y2) input.
4. Set the CH1 and CH2 on.
5. Set the ALT/CHOP/ADD button to CHOP mode.
6. Set the X-Y mode on by pressing and holding the button.
The figure 5-8 shows two X-Y waveforms in the dual X-Y mode.
Figure 5-8 Typical dual X-Y display
Setting Up delayed-sweep Operation
A delayed sweep is used to magnify any portion of a complex waveform
in the horizontal direction.
To display the delayed sweep operation, proceed the following steps:
1. Briefly pressing the MAIN/ALT/DELAY pushbutton to set to MAIN
time base of the horizontal mode. Effect triggering by main sweep and
set MAIN TIME/DIV control as desired.
Figure 5-7 Typical single X-Y display.
41
42
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
2. Set the MAIN/ALT/DELAY button to ALT mode, and set the time
range of the DELAY TIME/DIVE control to be magnified.
The figure 5-9 below shows the main and delayed sweeps appear
simultaneously on the screen, and the window sector will appear.
3.Adjust the DELAY TIME control to move continuously the window
sector. Bring the window sector to the position to be magnified. Then,
the waveform between the window sector is magnified to occupy the
full area of the screen.
4.If necessary, press the TRACE SEP pushbutton to set the LED on. The
delayed sweep trace can be shifted vertically about ±3 divisions with
respect to the main sweep trace for the convenience of observation by
the POSITION control.
Figure 5-9 ALT Mode Figure 5-10 Delay Mode
5.Set the DELAY mode to measure the magnified waveform only by
pressing the MAIN/ALT/DELAY button. The magnified waveform
shown in figure 5-10.
USER MANUAL
Magnifying Waveform Events
Use the ×10 MAG pushbutton to view small portions of a waveform as
which is too far back from the starting point to view by using the
TIME/DIV control. To use the ×10 MAG button, proceed the following
steps:
1. Adjust the TIME/DIV to the fastest sweep that displays the event.
2. Rotate the HORIZONTAL POSITION control to move the event to
display on the center of screen.
3. Press the ×10 MAG button to switch the MAG LED on.
When above procedures have been done, the displayed waveform will be
expanded 10 times to the right and left from the center of screen as center
of expansion.
Operating HO (Hold off time) Control
When the measured signal is a complex waveform with two or more
repetition frequencies (period), triggering with the LEVEL control alone
may not be sufficient to attain a stable waveform display. In such a case,
the sweep can be stable synchronized to the measured signal waveform
by adjusting the HO (Hold off) time of the sweep waveform.
Figure 5-11(a) shows several different waveforms which overlapped on
the screen, marking the signal observation unsuccessful when the hold
off is set to minimum (the HO-LED is dark).
Figure 5-11(b) shows the undesirable portion of the signal is held off.
The same waveforms are displayed on the screen without overlapping.
43
44
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
Figure 5-11(a)
Figure 5-11(b)
Triggering of Video signal
In the work concerned with TV, complex signals and containing video
signal, blanking pedestal signal, and synchronizing signal are often
measured.
Press the TRIG MODE pushbutton to set the TV position. The built-in
active TV-Sync-separator provides the separation of frame or line sync
pulses from the video signal. To trigger the oscilloscope at the vertical
(frame) rate, press the TV-V/TV-H pushbutton to set TV-V coupling. To
trigger the oscilloscope at the horizontal (line), press the TV-V/TV-H
pushbutton to set TV-H coupling. The figure 5-12(a) shows vertical
signal of TV-V and Figure 5-12(b) shows horizontal signal of TV-H.
USER MANUAL
Figure 5-12(a) TV-V Figure 5-12(b) TV-H
The polarity of the synchronization pulse is critical for the slope selection.
The figure 5-13(a) and 5-13(b) shows the examples of TV polarity
synchronization signals.
Figure 5-13(a) (–) Sync signal. Figure 5-13(b) (+) Sync signal
45
46
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
5-6.Measurement Appl icat ion
The oscilloscope has a cursor measurement system for making accurate,
direct-readout voltage, time, frequency and phase measurements. The
measurements described in this section are examples of typical
applications using this measurement system. After becoming familiar
with the controls, indicators, and capabilities of the instrument, you can
develop convenient methods to make the special measurement for your
own applications.
Proceed a measurement by using the cursor according to the following
steps:
1. Pressing and holding the CURSOR FUNCTION-ON/OFF pushbutton
to turn on the cursor and measurement readout.
2. Briefly pressing the pushbutton to select the seven measurement
function in the sequence as below:
△ V —△V% —△VdB —△T — 1/△T —△T% —△Θ —△V
3. If the associated indicator CURSOR POS-LED is lighted, rotate the
C1-POSITION control to position the cursor 1 and rotate the
C2-POSITION control to position the cursor 2.
4. Read the measurement value on the screen. Typical measurement
readouts and applications are shown in Figure 5-14. The measurement
values are automatically controlled by the VOLTS/DIV and TIME/DIV
control settings.
USER MANUAL
Figure 5-14: Cursor Measurement
(a).Typical △V (Voltage difference) for AC
voltage.
When both CH1 and CH2 are turned on, the
measurement value of CH1( △ V1) or
CH2(△V2) can be displayed by pressing
and holding the △V1/2 pushbutton.
(b).Typical △V%(Voltage percentage) cursor
measurement for overshoot of square
waveform.
A voltage percentage measurement is done
by first setting a reference for the full scale
(amplitude) waveform: 5div=100%.
(c).Typical △ VdB(voltage gain) cursor
measurement for –3dB bandwidth
application.
The percentage reference is: 5div=0db.
The measurement values calculate the
voltage gain from the formula:
△VdB=20 log(△Vdiv/5div)
(d).Typical △ T(Time difference) cursor
measurement for rise time.
Proceed rise-time or fall-time measurement
requiring some additional signal scaling by
using the graticale rise-time measurement aids.
Number 0%, 10, 90 and 100 are etched near
the left vertical gratical line. Use the following
steps as a guideline to in making rise-time measurement:
47
48
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
1. Set the VOLTS/DIV and VAR controls to provide an exact
five-division vertical display.
2. Use the vertical POSITION control to control the ne gative amplit ude
of the signal on the 0% reference line and the positive amplitude on
the 100% reference line.
3. Increase the TIME/DIV setting to stretch out the rising edge of the
waveform as much as possible to improve the cursor placement
accuracy.
4. Use the C1-POSITION control to align the cursor 1 to the rising
edge at the point where it crosses the 10% reference gratic ule line.
Then use the C2-POISITION control to align the cursor 2 to the
point where the rising edge crosses the 90% graticule line and read
the rise time displayed in the CRT readout.
(e).Typical 1/△T cursor function for frequency
measurement.
When the two cursors are superimposed at
two edge points of the one period waveform
by the C1-POSITION and C2-POSITION
controls, the measurement value is displayed
in frequency units on the upper side of the
screen.
(f).Typical △ T%(Time difference percentage)
cursor function for duty-cycle measurement
of square waveform.
A time difference percentage measurement is
done by first setting a reference for the full
cycle of waveform period: 5div=100%.
USER MANUAL
(g).Typical △Θcursor function for phase
measurement.
A phase measurement is done by first setting
o
a reference for the full 360
period:
5div-360
o
.
NOTE. When the VOLTS/DIV or the TIME/DIV controls are in
uncalibrated setting, the △V and △T measurement values will be
displayed with divisions.
When the vertical mode is set to the ADD mode, and the CH1 and CH2
VOLTS/DIV controls are set to different scales, the △V measurement
values will be displayed with divisions.
waveform
49
50
GOS-6112 OSCILLOSCOPE
GOS-6112 OSCILLOSCOPE
USER MANUAL
6.MAINTENENCE
The following instructions are executed by quali fied personnel only. To avoid
electrical shock, do not perform any servicing other than the operating
instructions unless you are qualified to do so.
6-1.Fuse Replacem ent
If the fuse blows, the power lamp indicators will not light and the
oscilloscope will not start. The fuse should not normally open unless a
problem has developed in the unit. Try to determine and correct the cause
of the blown fuse and replace only with a fuse of the correct rating and type
on the rear panel.
WARNING. For continued fire protection. Replace fuse
only with 250V fuse of the specified type and rating, and
disconnect power cord before replacing fuse.
6-2.Line Voltage Conversion
The primary winding of the power transformer is tapped to permit operation
from 100, 120 or 230VAC 50/60Hz line voltage. Conversion from one line
voltage to another is done by changing the line voltage selector switch as
shown in page 7. The rear panel ide ntifies the line vo ltage to which the unit
was factory set. To convert to a different line voltage, perform the
following procedur e:
(1).Make sure the power cord is unplugged.
(2).Adjust the line voltage selector switch to the desired line voltage
position.
(3).A change in line voltage may also require a corresponding change of
fuse value. Install the correct fuse value as listed on rear panel.
USER MANUAL
6-3.Cleaning
To clean the oscilloscope, use a soft cloth dampened in a solution of mild
detergent and water. Do not spray cleaner directly onto the oscilloscope
because it may leak into the cabinet and cause damage.
Do not use chemicals containing benzine, benzene, toluene, xylene,
acetone, or similar solvents. Do not use abrasive cleaners on any portion
of the oscilloscope.
51
52
GOS-6112 OSCILLOSCOPE
7.Block Diagram
USER MANUAL
53
Loading...