HAMEG HM1008 User Manual
100 MHz CombiScope
HM1008
Manual
English
®
Hersteller HAMEG Instruments GmbH KONFORMITÄTSERKLÄRUNG
Manufacturer Industriestraße 6 DECLARATION OF CONFORMITY
Fabricant D-63533 Mainhausen DECLARATION DE CONFORMITE
Die HAMEG Instruments GmbH bescheinigt die Konformität für das Produkt
The HAMEG Instruments GmbH herewith declares conformity of the product
HAMEG Instruments GmbH déclare la conformite du produit
Bezeichnung / Product name / Designation:
Oszilloskop
Oscilloscope
Oscilloscope
Typ / Type / Type: HM1008
mit / with / avec: –
Optionen / Options / Options: –
mit den folgenden Bestimmungen / with applicable regulations / avec les
directives suivantes
EMV Richtlinie 89/336/EWG ergänzt durch 91/263/EWG, 92/31/EWG
EMC Directive 89/336/EEC amended by 91/263/EWG, 92/31/EEC
Directive EMC 89/336/CEE amendée par 91/263/EWG, 92/31/CEE
Niederspannungsrichtlinie 73/23/EWG ergänzt durch 93/68/EWG
Low-Voltage Equipment Directive 73/23/EEC amended by 93/68/EEC
Directive des equipements basse tension 73/23/CEE amendée par 93/68/CEE
Angewendete harmonisierte Normen / Harmonized standards applied / Normes
harmonisées utilisées:
General information regarding the CE marking
HAMEG instruments fulfi ll the regulations of the EMC directive. The
conformity test made by HAMEG is based on the actual generic- and
product standards. In cases where different limit values are applicable,
HAMEG applies the severer standard. For emission the limits for
residential, commercial and light industry are applied. Regarding the
immunity (susceptibility) the limits for industrial environment have
been used.
The measuring- and data lines of the instrument have much infl uence
on emmission and immunity and therefore on meeting the acceptance
limits. For different applications the lines and/or cables used may
be different. For measurement operation the following hints and
conditions regarding emission and immunity should be observed:
1. Data cables
For the connection between instruments resp. their interfaces and
external devices, (computer, printer etc.) suffi ciently screened cables
must be used. Without a special instruction in the manual for a reduced
cable length, the maximum cable length of a dataline must be less than
3 meters and not be used outside buildings. If an interface has several
connectors only one connector must have a connection to a cable.
Basically interconnections must have a double screening. For IEEE-bus
purposes the double screened cables HZ72S and HZ72L from HAMEG
are suitable.
2. Signal cables
Basically test leads for signal interconnection between test point and
instrument should be as short as possible. Without instruction in the
manual for a shorter length, signal lines must be less than 3 meters
and not be used outside buildings.
Sicherheit / Safety / Sécurité: EN 61010-1:2001 (IEC 61010-1:2001)
Überspannungskategorie / Overvoltage category / Catégorie de surtension: II
Verschmutzungsgrad / Degree of pollution / Degré de pollution: 2
Elektromagnetische Verträglichkeit / Electromagnetic compatibility /
Compatibilité électromagnétique
EN 61326-1/A1 Störaussendung / Radiation / Emission:
Tabelle / table / tableau 4; Klasse / Class / Classe B.
Störfestigkeit / Immunity / Imunitée: Tabelle / table / tableau A1.
EN 61000-3-2/A14 Oberschwingungsströme / Harmonic current emissions /
Émissions de courant harmonique:
Klasse / Class / Classe D.
EN 61000-3-3 Spannungsschwankungen u. Flicker / Voltage fl uctuations and fl icker /
Fluctuations de tension et du fl icker.
Datum /Date /Date
24. 02. 2005
Unterschrift / Signature / Signatur
Manuel Roth
Manager
This will not cause damage or put the instrument out of operation. Small
deviations of the measuring value (reading) exceeding the instruments
specifi cations may result from such conditions in individual cases.
4. RF immunity of oscilloscopes.
4.1 Electromagnetic RF fi eld
The infl uence of electric and magnetic RF fi elds may become visible
(e.g. RF superimposed), if the fi eld intensity is high. In most cases
the coupling into the oscilloscope takes place via the device under
test, mains/line supply, test leads, control cables and/or radiation.
The device under test as well as the oscilloscope may be effected by
such fi elds.
Although the interior of the oscilloscope is screened by the cabinet,
direct radiation can occur via the CRT gap. As the bandwidth of
each amplifi er stage is higher than the total –3dB bandwidth of the
oscilloscope, the infl uence RF fi elds of even higher frequencies may
be noticeable.
4.2 Electrical fast transients / electrostatic discharge
Electrical fast transient signals (burst) may be coupled into the
oscilloscope directly via the mains/line supply, or indirectly via test
leads and/or control cables. Due to the high trigger and input sensitivity
of the oscilloscopes, such normally high signals may effect the trigger
unit and/or may become visible on the CRT, which is unavoidable.
These effects can also be caused by direct or indirect electrostatic
discharge.
HAMEG Instruments GmbH
Signal lines must screened (coaxial cable - RG58/U). A proper ground
connection is required. In combination with signal generators double
screened cables (RG223/U, RG214/U) must be used.
3. Infl uence on measuring instruments
Under the presence of strong high frequency electric or magnetic fi elds,
even with careful setup of the measuring equipment an infl uence of
such signals is unavoidable.
2
Subject to change without notice
Contents
General information regarding the CE marking 2
100 MHz CombiScope HM1008 4
Specifi cations 5
Important hints 6
List of symbols used: 6
Positioning the instrument 6
Safety 6
Proper operation 6
CAT I 6
Environment of use. 6
Environmental conditions 7
Warranty and repair 7
Maintenance 7
Line voltage 7
Description of the controls 8
Basic signal measurement 10
Signals which can be measured 10
Amplitude of signals 10
Values of a sine wave signal 10
DC and ac components of an input signal 11
Timing relationships 11
Connection of signals 11
AUTOSET 19
Component tester 19
CombiScope 21
DSO Operation 22
DSO operating modes 22
Memory resolution 22
Memory depth 23
Horizontal resolution with X magnifi er 23
Maximum signal frequency in DSO mode 23
Display of aliases 23
Vertical amplifi er operating modes 23
Data transfer 23
HO710: RS-232 Interface. Remote control 24
Selection of Baud rate 24
Data transmission 24
Loading of new fi rmware 24
General information concerning MENU 25
Controls and Readout 26
First time operation and initial adjustments 12
Trace rotation TR 12
Probe adjustment and use 12
1 kHz adjustment 12
1 MHz adjustment 13
Operating modes of the vertical amplifi er 13
XY operation 14
Phase measurements with Lissajous fi gures 14
Measurement of phase differences in dual
channel Yt mode 14
Measurement of amplitude modulation 15
Triggering and time base 15
Automatic peak triggering (MODE menu) 15
Normal trigger mode (See menu MODE) 16
Slope selection (Menu FILTER) 16
Trigger coupling (Menu: FILTER) 16
Video (tv triggering) 16
Frame sync pulse triggering 17
Line sync pulse triggering 17
LINE trigger 17
Alternate trigger 17
External triggering 17
Indication of triggered operation (TRIG’D LED) 17
Hold-off time adjustment 17
Time base B (2nd time base). Delaying,
Delayed Sweep. Analog mode. 18
Alternate sweep 18
Subject to change without notice
3
HM1008
1 GSa/s Real Time Sampling, 10 GSa/s Random Sampling
1 MPt memory per channel allows Memory oom
up to 50,000:1
Two Channels 1mV – 20 V/cm
8-Bit Low Noise Flash A/D Converters
Pre/Post Trigger -100 % to +400 %
Time Base 50 s/cm – 5 ns/cm
Acquisition modes: Single Event, Refresh, Average, Envelope,
Roll, Peak-Detect
RS-232 Interface, optional: USB/RS-232, IEEE-488,
Ethernet/USB
Signal display: Yt and XY;
Interpolation: Sinx/x, Pulse, Dot Join (linear)
Analog Mode: see HM1000-2
100 MHz CombiScope
®
HM1008
Cursor measurement
choices in digital mode
Digital Mode: TV field and
zoomed display of one
selected line
Either PAL or NTSC: Line
triggering with line counter
4
Subject to change without notice
Technische Daten
100 MHz CombiScope®HM1008
Valid at 23 °C after a 30 minute warm-up period
Vertical Deflection
Channels:
Analog: 2
Digital: 2
Operating Modes:
Analog: CH 1 or CH 2 separate, DUAL (CH 1 and
CH 2 alternate or chopped), Addition
Digital: CH 1 or CH 2 separate, DUAL (CH 1 and
CH 2), Addition
X in XY-Mode: CH 1
Invert: CH 1, CH 2
Bandwidth (-3 dB): 2 x 0 - 100 MHz
Rise time: ‹ 3.5 ns
Overshoot: max. 1 %
Bandwith limiting (selectable): about 20 MHz (5 mV/cm - 20V/cm)
Deflection Coefficients(CH 1, 2):14 calibrated steps
1mV – 2mV/cm (10MHz) ±5% (0 - 10 MHz (-3dB))
5 mV – 20 V/cm ±3% (1-2-5 sequence)
variable (uncalibrated): › 2.5 :1 to › 50V/cm
Inputs CH 1, 2:
Input Impedance: 1 MΩ II 15 pF
Coupling: DC, AC, GND (ground)
Max. Input Voltage: 400 V (DC + peak AC)
Y Delay Line (analog): 70 ns
Measuring Circuits: Measuring Category I
Anal
og mode only:
Auxiliary input:
Function (selectable): Extern Trigger, Z (unblank)
Coupling: AC, DC
Max. input voltage: 100 V (DC +peak AC)
Triggering
Analog and Digital Mode
Automatic (Peak to Peak):
Min. signal height: 5mm
Frequency range: 10Hz - 200 MHz
Level control range: from Peak- to Peak+
Normal (without peak): Slope/Video
Min. signal height: 5mm
Frequency range: 0 - 200MHz
Level control range: –10 cm to +10cm
Operating modes: Slope/Video
Slope: positive, negative, both
Sources: CH 1, CH 2, alt. CH 1/2 (≥ 8mm), Line, Ext.
Coupling: AC: 10 Hz-200MHz
DC: 0 -200 MHz
HF: 30 kHz–200 MHz
LF: 0-5kHz
Noise Rej. switchable
Video: pos./neg. Sync. Impulse
Standards: 525 Line/60Hz Systems
625 Line/50Hz Systems
Field: even/odd /both
Line: all/line number selectable
Source: CH 1, CH 2, Ext.
Indicator for trigger action: LED
External Trigger via: Auxiliary Input (0.3Vpp, 100 MHz)
Coupling: AC, DC
Max. input voltage: 100 V (DC +peak AC)
Digital mode
Pre/Post Trigger: -100 % to +400% related to complete memory
Analog mode
2nd Trigger
Min. signal height: 5mm
Frequency range: 0 - 200MHz
Coupling: DC
Level control range: –10 cm to +10cm
Horizontal Deflection
Analog mode
Operating modes: A, ALT (alternating A/B), B
Time base A: 0.5s/cm - 50 ns/cm (1-2-5 sequence)
Time base B: 20 ms/cm – 50 ns/cm (1-2-5 sequence)
Accuracy A and B: ±3%
X Magnification x10: to 5 ns/cm
Accuracy: ±5%
Variable time base A/B: cont. 1:2.5
Hold Off time: var. 1:10 (LED-Indication)
Bandwidth X-Amplifier: 0 - 3 MHz (-3dB)
X Y phase shift ‹ 3°: ‹ 220kHz
Digit
al mode
Time base range (1-2-5 sequence)
Refresh Mode: 20 ms/cm - 5 ns/cm
with Peak Detect: 20ms/cm – 2 ms/cm (min. Pulse Width 10 ns)
Roll Mode: 50s/cm – 50 ms/cm
Accuracy time base
Time base: 50 ppm
Display: ±1%
MEMORY ZOOM: max. 50,000:1
Bandwidth X-Amplifier: 0 - 100 MHz (-3dB)
X Y phase shift ‹ 3°: ‹ 100 MHz
Digital Storage
Sampling rate (real time): 2x 500 MSa/s, 1 GSa/s interleaved
Sampling rate (random sampling): 10GSa/s
Bandwidth: 2 x 0 - 100 MHz (random)
Memory: 1 M-Samples per channel
Operating modes: Refresh, Average, Envelope/
Roll: Free Run/Triggered, Peak-Detect
Resolution (vertical): 8 Bit (25 Pts/cm)
Resolution (horizontal):
Yt: 11 Bit (200 Pts/cm)
XY: 8 Bit (25 Pts /cm)
Interpolation: Sinx/x, Dot Join (linear)
Delay: 1 Million x 1/Sampling Rate to
4 Million x 1/Sampling Rate
Display refresh rate: max.170 /s at 1 MPts
Display: Dots (acquired points only), Vectors (partly
interpolated), optimal (complete memory
weighting and vectors)
Reference Memories: 9 with 2 kPts each (for recorded signals)
Display: 2 signals of 9 (free selectable)
Operation/Measuring/Interfaces
Operation: Menu (multilingual), Autoset,
help functions (multilingual)
Save/Recall (instrument parameter settings): 9
Signal display: max. 4 traces
analog: CH 1, 2 (Time Base A) in combination with
CH 1, 2 (Time Base B)
digital: CH1,2 and ZOOM or Reference or
Mathematics)
Frequency counter:
6 digit resolution: ›1 MHz – 200MHz
5 digit resolution: 0.5 Hz – 1MHz
Accuracy: 50ppm
Auto Measurements:
Analog mode: Frequency, Period, Vdc, Vpp, Vp+, Vp-
also in digital mode: V
rms
, V
avg
Cursor Measurements:
Analog mode: Δt, 1/Δt (f), tr, ΔV, V to GND, ratio X, ratio Y
plus in digital mode: V
pp
, Vp+, Vp-, V
avg
, V
rms
, pulse count
Resolution Readout/Cursor: 1000 x 2000Pts, Signals: 250 x 2000
Interfaces (plug-in): RS-232 (HO710)
Optional: IEEE-488, Ethernet, Dual-Interface
RS-232/USB
Mathematic functions
Number of Formula Sets: 5 with 5 formulas each
Sources: CH 1, CH 2, Math 1-Math 5
Targets: 5 math. memories, Math 1-5
Functions: ADD, SUB, 1/X, ABS, MUL, DIV, SQ, POS,
NEG, INV
Display: max. 2 math. memories (Math 1-5)
Display
CRT: D14-375GH
Display area (with graticule): 8cm x 10cm
Acceleration voltage: approx. 14 kV
General Information
Component tester
Test voltage: approx. 7V
rms
(open circuit), approx. 50 Hz
Test current: max. 7 mA
rms
(short circuit)
Reference Potential : Ground (safety earth)
Probe ADJ Output: 1 kHz/1 MHz square wave signal 0.2 V
pp
(tr ‹ 4 ns)
Trace rotation: electronic
Line voltage: 105 – 253 V, 50/60 Hz ±10 %, CAT II
Power consumption: 42 Watt at 230V, 50Hz
Protective system: Safety class I (EN61010-1)
Weight: 5.6 kg
Cabinet (W x H x D): 285 x 125 x 380mm
Ambient temperature: 0° C ...+40° C
Accessories supplied: Line cord, Operating manual, 2 Probes 10:1 with at tenuation ID, Windows Software for control and data transfer
Optional accessories: HO720 Dual-Inter face RS-232/USB, HO730 Dual-Inter face Ethernet/ USB, HO740 Interface IEEE-488 (GPIB), HZ70 Opto-Interface (with
optical fi ber cable)
Subject to change without notice
5
Important hints
Important hints
Please check the instrument for mechanical damage or loose
parts immediately after unpacking. In case of damage we advise
to contact the sender. Do not operate.
List of symbols used:
Consult the manual High voltage
Important note Ground
Positioning the instrument
As can be seen from the fi gures, the handle can be set into
different positions:
A = carrying
B = handle removal and horizontal carrying
C = horizontal operating
D and E = operating at different angles
F = handle removal
T = shipping (handle unlocked)
B
C
B
T
A
C
D
F
E
D
E
A
PUkT
PUOGkT
PUkT
ANALOG
PUOPFGkT
PUkT
HGOFFD
PUOPFGkT
PUOPFGkT
HGOPFFD
DIGITAL
MIXED SIGNAL
COMBISCOPE
PUkT
HM1508
PUOPFGkT
PUOPFGkT
PFGkT
PUkT
1 GSa · 1MB
PUkT
150 MHz
PUOPFGkT PUOPFGkT
PUOPFGkT
VOLTS/DIVV
HGOPFFD
B
HAMEG
C O M B I S C O P E
PUk PUk
PUkT
PUkT
PUOPFGkT
PUOPFGkT
PUkT
PUOPF
PUOPF
PUkT
PUOPF
HGOPFFD
PUkT
PUkT
VOLTS/DIVV
VOLTS/DIVV
HGOPFFD
HGOPFFD
PUkT
PUOPFGkT
PUkT
HGOPFFD
PUkT
PUOPFGkT
PUk PUk
PUk PUk
PUOPFGkT
PGkT
PUkT PUkT
PUOPFGkT
PUOPFGkT
PUOPF PUOPF
PUOPFGkT
INPUTS
PUkTKl
PUkTKl
15pF
15pF
max
max
400 Vp
400 Vp
PUkT
Attention!
When changing the handle position, the instrument
must be placed so that it can not fall (e.g. placed
on a table). Then the handle locking knobs must be
simultaneously pulled outwards and rotated to the
required position. Without pulling the locking knobs
they will latch in into the next locking position.
Handle mounting/dismounting
The handle can be removed by pulling it out further, depending
on the instrument model in position B or F.
Safety
The instrument fulfi ls the VDE 0411 part 1 regulations for
electrical measuring, control and laboratory instruments and
was manufactured and tested accordingly. It left the factory in
perfect safe condition. Hence it also corresponds to European
Standard EN 61010-1 resp. International Standard IEC 1010-1.
In order to maintain this condition and to ensure safe operation
the user is required to observe the warnings and other directions
for use in this manual. Housing, chassis as well as all measuring terminals are connected to safety ground of the mains.
All accessible metal parts were tested against the mains with
2200 V
The oscilloscope may only be operated from mains outlets with
a safety ground connector. The plug has to be installed prior to
connecting any signals. It is prohibited to separate the safety
ground connection.
Most electron tubes generate X-rays; the ion dose rate of this instrument remains well below the 36 pA/kg permitted by law.
. The instrument conforms to safety class I.
DC
T
T
Safe operation may be endangered if any of the following
was noticed:
– in case of visible damage.
– in case loose parts were noticed
– if it does not function any more.
– after prolonged storage under unfavourable conditions (e.g.
like in the open or in moist atmosphere).
– after any improper transport (e.g. insuffi cient packing not
conforming to the minimum standards of post, rail or transport fi rm)
Proper operation
Please note: This instrument is only destined for use by personnel well instructed and familiar with the dangers of electrical
measurements.
For safety reasons the oscilloscope may only be operated from
mains outlets with safety ground connector. It is prohibited
to separate the safety ground connection. The plug must be
inserted prior to connecting any signals.
CAT I
In case safe operation may not be guaranteed do not use the
instrument any more and lock it away in a secure place.
6
Subject to change without notice
This oscilloscope is destined for measurements in circuits not
connected to the mains or only indirectly. Direct measurements,
Important hints
i.e. with a galvanic connection to circuits corresponding to the
categories II, III, or IV are prohibited!
The measuring circuits are considered not connected to the
mains if a suitable isolation transformer fulfi lling safety class
II is used. Measurements on the mains are also possible if
suitable probes like current probes are used which fulfi l the
safety class II. The measurement category of such probes must
be checked and observed.
Measurement categories
The measurement categories were derived corresponding to
the distance from the power station and the transients to be
expected hence. Transients are short, very fast voltage or current excursions which may be periodic or not.
Measurement CAT IV:
Measurements close to the power station, e.g. on electricity
meters
Measurement CAT III:
Measurements in the interior of buildings (power distribution
installations, mains outlets, motors which are permanently
installed).
Measurement CAT II:
Measurements in circuits directly connected to the mains
(household appliances, power tools etc).
Environment of use.
The oscilloscope is destined for operation in industrial, business,
manufacturing, and living sites.
Environmental conditions
check all operating modes and fulfi lment of specifi cations. The
latter is performed with test equipment traceable to national
measurement standards.
Statutory warranty regulations apply in the country where the
HAMEG product was purchased. In case of complaints please
contact the dealer who supplied your HAMEG product.
Maintenance
Clean the outer shell using a dust brush in regular intervals.
Dirt can be removed from housing, handle, all metal and plastic
parts using a cloth moistened with water and 1 % detergent.
Greasy dirt may be removed with benzene (petroleum ether) or
alcohol, there after wipe the surfaces with a dry cloth. Plastic
parts should be treated with an antistatic solution destined
for such parts. No fl uid may enter the instrument. Do not use
other cleansing agents as they may adversely affect the plastic
or lacquered surfaces.
Line voltage
The instrument has a wide range power supply from 105 to 253
V, 50 or 60 Hz ±10%. There is hence no line voltage selector.
The line fuse is accessible on the rear panel and part of the line
input connector. Prior to exchanging a fuse the line cord must
be pulled out. Exchange is only allowed if the fuse holder is
undamaged, it can be taken out using a screwdriver put into the
slot. The fuse can be pushed out of its holder and exchanged.
The holder with the new fuse can then be pushed back in place
against the spring. It is prohibited to ”repair“ blown fuses or to
bridge the fuse. Any damages incurred by such measures will
void the warranty.
Operating ambient temperature: 0 to + 40 degrees C. During
transport or storage the temperature may be –20 to +55 degrees C.
Please note that after exposure to such temperatures or in case
of condensation proper time must be allowed until the instrument has reached the permissible range of 0 to + 40 degrees
resp. until the condensation has evaporated before it may be
turned on! Ordinarily this will be the case after 2 hours. The
oscilloscope is destined for use in clean and dry environments.
Do not operate in dusty or chemically aggressive atmosphere
or if there is danger of explosion.
The operating position may be any, however, suffi cient ventilation must be ensured (convection cooling). Prolonged operation
requires the horizontal or inclined position.
Do not obstruct the ventilation holes!
Specifi cations are valid after a 20 minute warm-up period
between 15 and 30 degr. C. Specifi cations without tolerances
are average values.
Warranty and repair
HAMEG instruments are subjected to a rigorous quality control.
Prior to shipment each instrument will be burnt in for 10 hours.
Intermittent operation will produce nearly all early failures.
After burn in, a fi nal functional and quality test is performed to
Type of fuse:
Size 5 x 20 mm; 250V~, C;
IEC 127, Bl. III; DIN 41 662
(or DIN 41 571, Bl. 3).
Cut off: slow blow (T) 0,8A.
Subject to change without notice
7
Front Panel Elements – Brief Description
Front Panel Elements – Brief Description
The fi gures indicate the page for complete discriptions
POWER (pushbutton switch) 26
Turns scope on and off.
INTENS (knob) 26
Intensity for trace- and readout brightness, focus and trace
rotation control.
FOCUS, TRACE, MENU (pushbutton switch) 26
Calls the Intensity Knob menu to be displayed and enables
the change of different settings by aid of the INTENS knob.
See item 2.
REM (pushbutton switch) 26
Switches the displayed menu, the remote mode (REM lit)
off.
ANALOG/DIGITAL (pushbutton switch) 27
Switches between analog (green) and digital mode (blue).
STOP / RUN (pushbutton switch) 27
RUN: Signal data acquisition enabled.
STOP: Signal data acquisition disabled. The result of the last
acquisition is displayed.
MATH (pushbutton switch) 27
Calls mathematical function menu if digital mode is pre-
sent.
ACQUIRE (pushbutton switch) 28
Calls the signal capture and display mode menu in digital
mode.
SAVE/RECALL (pushbutton switch) 29
Offers access to the reference signal (digital mode only) and
the instrument settings memory.
SETTINGS (pushbutton switch) 30
Opens menu for language and miscellaneous function; in
digital mode also signal display mode.
AUTOSET (pushbutton switch) 30
Enables appropriate, signal related, automatic instrument
settings.
in the chapter CONTROLS AND READOUT
▼
VOLTS/DIV-SCALE-VAR (knob) 32
Channel 2 Y defl ection coeffi cient, Y variabel and Y scaling
setting.
AUTO / CURSOR MEASURE (pushbutton switch) 33
Calls menus and submenus for automatic and cursor sup-
ported measurement.
LEVEL A/B (knob) 34
Trigger level control for time base A and B.
MODE (pushbutton switch) 34
Calls selectable trigger modes.
FILTER (pushbutton switch) 35
Calls selectable trigger fi lter (coupling) and trigger slope
menu.
SOURCE (pushbutton switch) 35
Calls trigger source menu.
TRIG’d (LED) 36
Lit on condition that time base is triggered.
NORM (LED) 36
Lit on condition that NORMAL or SINGLE triggering is pre-
sent.
HOLD OFF (LED) 36
Lit if a hold off time > 0% is chosen in time base menu (HOR
pushbutton
X-POS / DELAY (pushbutton switch) 36
Calls and indicates the actual function of the HORIZONTAL
knob
HORIZONTAL (knob) 37
Changes the X position resp. in digital mode the delay time
(Pre- resp. Post-Trigger).
TIME/DIV-SCALE-VAR (knob) 37
Time base A and B defl ection coeffi cient, time base variable
and scaling control.
MAG (pushbutton switch) 37
10 fold expansion in X direction in Yt mode, with simulta-
neous change of the defl ection coeffi cient display in the
readout.
).
, (X-POS = dark).
HELP (pushbutton switch) 30
Switches help texts regarding controls and menus on and
off.
POSITION 1 (knob) 30
Controls position of actual present functions: Signal (cur-
rent, reference or mathematics), Cursor and ZOOM (digital).
POSITION 2 (knob) 31
Controls position of actual present functions: Signal (current,
reference or mathematics) Cursor and ZOOM (digital).
CH 1/2-CURSOR-CH3/4-MA/REF-ZOOM (pushbutton) 32
Calls the menu and indicates the current function of
POSITION 1 and 2 controls.
VOLTS/DIV-SCALE-VAR (knob) 32
Channel 1 Y defl ection coeffi cient, Y variabel and Y scaling
setting.
8
Subject to change without notice
HOR / VAR (pushbutton switch) 38
Calls ZOOM function (digital) and analog time base A and
B, time base variable and hold off control.
CH1 (pushbutton switch) 39
Calls channel 1 menu with input coupling, inverting, probe
and Y variable control.
VERT/XY (pushbutton switch) 39
Calls vertical mode selection, addition, XY mode and band-
width limiter.
CH2 (pushbutton switch) 41
Calls channel 1 menu with input coupling, inverting, probe
and Y variable control.
CH1 (BNC-socket) 41
Channel 1 signal input and input for horizontal defl ection in
XY mode.
Front Panel Elements – Brief Description
POWER
POWER
15
13
14
17
16
18
1 2 3
INTENS
POWER
!
EXIT MENU
REMOTE OFF
POSITION 1 POSITION 2
VOLTS / DIV
SCALE · VAR
20 V 1 mV 20 V 1 mV
CH 1
VAR
X-INP
!
CAT I
FOCUS
TRACE
MENU
REM
CH 1/2
CURSOR
MA/REF
ZOOM
AUTO/
CURSOR
MEASURE
VERT/XY
INPUTS
1MΩII15pF
max
400 Vp
4
ANALOG
DIGITAL
5 6 7 8 9 10 11 12
ANALOG
DIGITAL
MATH
RECALL
OSCILLOSCOPE
HM1008
·
1 MB
1 GSa
100 MHz
VOLTS / DIV
SCALE · VAR
CH 2 HOR MAG
RUN ACQUIRE SETTINGS HELP
STOP
LEVEL A/B
TRIGGER
MODE
FILTER
SOURCE
AUX
X-POS
DELAY
TRIG ’d
NORM
HOLD OFF
VAR
AUXILIARY INPUT
TRIGGER
EXTERN
!
CAT I
Z-INPUT
SAVE/
AUTOSET
HORIZONTAL
TIME / DIV
SCALE · VAR
50s 5ns
VAR
x10
1MΩ II
15pF
max
100 Vp
19
26
27
20
23
21
24
28
22
25
29
30
3431
32
33
35
MEMORY
COMBISCOPE
oom
CH2 (BNC-socket) 41
Channel 2 signal input.
AUX (pushbutton switch) 41
Calls AUXILIARY INPUT menu with intensity modulation (Z)
and external triggering selectable.
AUXILIARY INPUT (BNC-socket) 41
Input for external trigger or intensity (Z) modulation si-
gnal.
36
37
COMPONENT
TESTER
40
PROBE
ADJ
3839
PROBE / COMPONENT (pushbutton switch) 42
Calls COMPONENT TESTER mode settings and frequency
selection of PROBE ADJ signal.
COMPONENT TESTER (2 sockets with 4 mm Ø) 42
Connectors for test leads of the Component Tester. Left
socket is galvanically connected with protective earth.
PROBE / ADJ (socket) 42
Square wave signal output for frequency compensation of
x10 probes.
Subject to change without notice
9
Basic signal measurement
Basic signal measurement
Signals which can be measured
The following description pertains as well to analog as to
DSO operation. The different specifi cations in both operating
modes should be kept in mind.
The oscilloscope HM1008 can display all repetitive signals
with a fundamental repetition frequency of at least 100 MHz.
The frequency response is 0 to 100 MHz (-3 dB). The vertical
amplifi ers will not distort signals by overshoots, undershoots,
ringing etc.
Simple electrical signals like sine waves from line frequency
ripple to hf will be displayed without problems. However,
when measuring sine waves, the amplitudes will be displayed
with an error increasing with frequency. At 80 MHz the amplitude error will be around –10 %. As the bandwidths of individual instruments will show a certain spread (the 100 MHz
are a guaranteed minimum) the actual measurement error
for sine waves cannot be exactly determined.
Pulse signals contain harmonics of their fundamental frequency which must be represented, so the maximum useful
repetition frequency of nonsinusoidal signals is much lower
than 100 MHz. The criterion is the relationship between the
rise times of the signal and the scope; the scope’s rise time
should be <1/3 of the signal’s rise time if a faithful reproduction without too much rounding of the signal shape is to
be preserved.
The display of a mixture of signals is especially diffi cult
if it contains no single frequency with a higher amplitude
than those of the other ones as the scope’s trigger system
normally reacts to a certain amplitude. This is e.g. typical of
burst signals. Display of such signals may require using the
HOLD-OFF control.
Composite video signals may be displayed easily as the instrument has a tv sync separator.
The maximum sweep speed of 5 ns/cm allows suffi cient time
resolution, e.g. a 100 MHz sine wave will be displayed one
period per 2 cm.
The vertical amplifi er inputs may be dc or ac coupled. Use dc
coupling only if necessary and preferably with a probe.
Low frequency signals when ac coupled will show tilt (ac low
frequency – 3 dB point is 1.6 Hz), so if possible use dc coupling.
Using a probe with 10:1 or higher attenuation will lower the
–3 dB point by the probe factor. If a probe cannot be used
due to the loss of sensitivity dc coupling the scope and an
external large capacitor may help which, of course, must have
a suffi cient dc rating. Care must be taken, however, when
charging and discharging a large capacitor.
Amplitude of signals
In contrast to the general use of rms values in electrical engineering oscilloscopes are calibrated in Vpp as that is what is
displayed.
Derive rms from V
: divide by 2.84. Derive Vpp from rms: mul-
pp
tiply by 2.84.
Values of a sine wave signal
V
p
V
rms
V
mom
V
pp
V
= rms value
rms
V
= pp – value
PP
V
= momentary value, depends on time vs. period.
mom
The minimum signal for a one cm display is 1 mV
ded 1 mV/cm was selected and the variable is in the calibrated
position.
The available sensitivities are given in mV
pp
allow to indicate the amplitudes of the signals immediately on
the readout as the attenuation of probes is automatically taken
into account. Even if the probe attenuation was selected manually this will be overridden if the scope identifi es a probe with
an identifi cation contact as different. The readout will always
give the true amplitude.
It is important that the variable be in its calibrated position. The
sensitivity may be continuously decreased by using the variable
(see Controls and Readout). Each intermediate value between
the calibrated positions 1–2–5 may be selected. Without using
a probe thus a maximum of 400 V
may be displayed (20 V/div
PP
x 8 cm screen x 2.5 variable).
Amplitudes may be directly read off the screen by measuring
the height and multiplying by the V/div. setting.
Please note: Without a probe the maximum permis-
sible voltage at the inputs must not exceed 400 V
irrespective of polarity.
In case of signals with a dc content the peak value DC + AC
peak must not exceed + or – 400 V
. Pure AC of up to 800 VPP
P
is permissible.
If probes are used their possibly higher ratings are
only usable if the scope is dc coupled.
±5 % provi-
pp
or Vpp. The cursors
p
Dc coupling is preferable with all signals of varying duty cycle, otherwise the display will move up and down depending
on the duty cycle. Of course, pure dc can only be measured
with dc coupling.
The readout will show which coupling was chosen: = stands
for DC, ~ stands for AC.
10
Subject to change without notice
In case of measuring dc with a probe while the scope input is
ac coupled the capacitor in the scope input will see the input
dc voltage as it is in series with the internal 1 MΩ resistor.
This means that the maximum dc voltage (or DC + peak AC) is
that of the scope input, i.e. 400 V
! With signals which contain
P
dc and ac the dc content will stress the input capacitor while
the ac content will be divided depending on the ac impedance
of the capacitor. It may be assumed that this is negligible for
frequencies >40 Hz.
Considering the foregoing you may measure dc signals of up
to 400 V or pure ac signals of up to 800 V
with a HZ200 probe.
PP
Probes with higher attenuation like HZ53 100:1 allow to measure
dc up to 1200 V and pure ac of up to 2400 V
. (Please note the
PP
derating for higher frequencies, consult the HZ53 manual).
Stressing a 10:1 probe beyond its ratings will risk destruction of
the capacitor bridging the input resistor with possible ensuing
damage of the scope input!
In case the residual ripple of a high voltage is to be measured a
high voltage capacitor may be inserted in front of a 10:1 probe, it
will take most of the voltage as the value of the probe’s internal
capacitor is very low, 22 to 68 nF will be suffi cient.
If the input selector is switched to Ground the reference trace
on the screen may be positioned at graticule center or elsewhere.
DC and ac components of an input signal
voltage
peak
AC
DC
DC + AC
DC
AC
peak
= 400 V
max
The dashed curve shows an ac signal symmetrical to zero.
If there is a dc component the peak value will be dc + ac peak.
Timing relationships
The repetition frequency of a signal is equal to the number of
periods per second. Depending on the TIME/DIV setting one or
more periods or part of a period of the signal may be displayed.
The time base settings will be indicated on the readout in s/cm,
ms/cm, μs/cm and ns/cm. Also the cursors may be used to
measure the frequency or the period.
If portions of the signal are to be measured use delayed sweep
(analog mode) or zoom (DSO mode) or the magnifi er x 10. Use
the HORIZONTAL positioning control to shift the portion to be
zoomed into the screen center.
Pulse signals are characterized by their rise and fall times
which are measured between the 10 % and 90 % portions. The
following example uses the internal graticule of the crt, but also
the cursors may be used for measurement.
Measurement:
– Adjust the rising portion of the signal to 5 cm.
– Position the rising portion symmetrically to the graticule
centre line, using both Y and X positioning controls.
– Notice the intersections of the signal with the 10 and 90 %
lines and project these points to the centre line in order to
read the time difference.
Basic signal measurement
100%
90%
5 cm
10%
0%
t
tot
In the example it was 1.6 cm at 5 ns/cm equals 8 ns rise time.
When measuring very short rise times coming close to the scope
rise time it is necessary to subtract the scope’s (and if used the
probe’s) rise times geometrically from the rise time as seen on
the screen. The true signal rise time will become:
2
2
ta= t
t
is the rise time seen, t
tot
– t
tot
(3.5 ns with the HM1008), t
2
– t
osc
t
is the scope’s own rise time
osc
is the rise time of the probe, e.g.
t
2 ns. If the signal’s rise time is > 34 ns, the rise times of scope
and probe may be neglected.
ta= 82 - 3.52 - 22 = 6.9 ns
For the measurement of rise times it is not necessary to proceed
as outlined above. Rise times may be measured anywhere on
the screen. It is mandatory that the rising portion of the signal
be measured in full and that the 10 to 90 % are observed. In
case of signals with over- or undershoot the 0 and 100 % levels
are those of the horizontal portions of the signal, i.e. the overresp. undershoots must be disregarded for rise and fall time
measurements. Also, glitches will be disregarded. If signals
are very distorted, however, rise and fall time measurements
may be of no value.
For most amplifi ers, even if their pulse behaviour is far from
ideal, the following relationship holds:
350 350
t
=
——
a
B t
B =
——
a
tr/ns = 350/Bandwidth/MHz
Connection of signals
In most cases pressing the AUTOSET button will yield a satisfactory display (see AUTOSET). The following relates to special
cases where manual settings will be advisable. For a description
of controls refer to ”Controls and Readout“.
Take care when connecting unknown signals to the
inputs!
It is recommended to use probes whenever possible. Without
a probe start with the attenuator set to its 20 V/cm position.
If the trace disappears the signal amplitude may be too large
overdriving the vertical amplifi er or/and its dc content may be
too high. Reduce the sensitivity until the trace will reappear
onscreen. If calibrated measurements are desired it will be
necessary to use a probe if the signal becomes >160 Vp. Check
the probe specifi cations in order to avoid overstressing. If the
time base is set too fast the trace may become invisible, then
reduce the time base speed.
If no probe is used at least screened cable should be used,
such as HZ32 or HZ34. However, this is only advisable for low
Subject to change without notice
11
First time operation and initial adjustments
impedance sources or low frequencies (<50 kHz). With high
frequencies impedance matching will be necessary.
Nonsinusoidal signals require impedance matching, at both
ends preferably. At the scope input a feed through – 50 Ω-termination will be required. HAMEG offers a HZ22 termination. If
proper terminations are not used sizeable pulse aberrations will
result. Also sine wave signals of > 100 kHz should be properly
terminated. Most generators control signal amplitudes only if
correctly terminated.
HZ22 may only be used up to 7 V
or 20 VPP i.e. 1 W.
rms
For probes terminations are neither required nor allowed, they
would ruin the signal.
Probes feature very low loads at fairly low frequencies: 10 MΩ in
parallel to a few pF, valid up to several hundred kHz. However,
the input impedance diminishes with rising frequency to quite
low values. This has to be borne in mind as probes are, e.g.,
entirely unsuitable to measure signals across high impedance
high frequency circuits such as bandfi lters etc.! Here only FET
probes can be used. Use of a probe as a rule will also protect
the scope input due to the high probe series resistance (9 MΩ).
As probes cannot be calibrated exactly enough during manufacturing individual calibration with the scope input used is
mandatory! (See Probe Calibration).
Passive probes will, as a rule, decrease the scope bandwidth
resp. increase the rise time. We recommend to use HZ200 probes in order to make maximum use of the combined bandwidth.
HZ200 features 2 additional hf compensation adjustments.
First time operation and initial adjustments
Prior to fi rst time operation the connection between the instrument and safety ground must be ensured, hence the plug must
be inserted fi rst.
Use the red pushbutton POWER to turn the scope on. Several
displays will light up. The scope will then assume the set-up,
which was selected before it was turned off. If no trace and
no readout are visible after approximately 20 sec, push the
AUTOSET button.
As soon as the trace becomes visible select an average intensity with INTENS, then select FOCUS and adjust it, then select
TRACE ROTATION and adjust for a horizontal trace.
With respect to crt life use only as much intensity as necessary
and convenient under given ambient light conditions, if unused
turn the intensity fully off rather than turning the scope off and
on too much, this is detrimental to the life of the crt heater.
Do not allow a stationary point to stay, it might burn the crt
phosphor.
With unknown signals start with the lowest sensitivity 20 V/cm,
connect the input cables to the scope and then to the measuring object which should be deenergized in the beginning. Then
turn the measuring object on. If the trace disappears, push
AUTOSET.
Whenever the DC content is > 400 V
coupling must be used in
DC
order to prevent overstressing the scope input capacitor. This is
especially important if a 100:1 probe is used as this is specifi ed
for 1200 V
+ peak AC.
DC
AC coupling of low frequency signals may produce tilt.
If the dc content of a signal must be blocked it is possible to
insert a capacitor of proper size and voltage rating in front of the
probe, a typical application would be a ripple measurement.
When measuring small voltages the selection of the ground
connection is of vital importance. It should be as close to voltage
take-off point as possible, otherwise ground currents may deteriorate the measurement. The ground connections of probes
are especially critical, they should be as short as possible and
of large size.
If a probe is to be connected to a BNC connector use
a probe tip to BNC adapter.
If ripple or other interference is visible, especially at high sensitivity, one possible reason may be multiple grounding. The
scope itself and most other equipment are connected to safety
ground, so ground loops may exist. Also, most instruments will
have capacitors between line and safety ground installed which
conduct current from the live wire into the safety ground.
Trace rotation TR
The crt has an internal graticule. In order to adjust the defl ected
beam with respect to this graticule the Trace Rotation control
is provided. Select the function Trace Rotation and adjust for a
trace which is exactly parallel to the graticule.
Probe adjustment and use
In order to ensure proper matching of the probe used to the
scope input impedance the scope contains a calibrator with
short rise time and an amplitude of 0.2 V
± 1 %, equivalent to
pp
4 cm at 5 mV/cm when using 10:1 probes.
The inner diameter of the calibrator connector is 4.9 mm and
standardized for series F probes. Using this special connector is the only way to connect a probe to a fast signal source
minimizing signal and ground lead lengths and to ensure true
displays of pulse signals.
1 kHz adjustment
This basic adjustment will ensure that the capacitive attenuation
equals the resistive attenuation thus rendering the attenuation
of the probe independent of frequency. 1:1 probes can not be
adjusted and need no such adjustment anyway.
12
Subject to change without notice
incorrect correct incorrect
Operating modes of the vertical amplifier
Prior to adjustment make sure that the trace rotation adjustment was performed.
Connect the 10:1 probe to the input. Use dc coupling. Set
the VOLTS/DIV to 5 mV/cm and TIME/DIV to 0.2 ms/cm, both
calibrated. Insert the probe tip into the calibrator connector
PROBE ADJ.
You should see 2 signal periods. Adjust the compensation capacitor (see the probe manual for the location) until the square
wave tops are exactly parallel to the graticule lines (see picture
1 kHz). The signal height should be 4 cm ±1.6 mm (3% oscilloscope and 1% probe tolerance). The rising and falling portions
of the square wave will be invisible.
1 MHz adjustment
The HAMEG probes feature additional adjustments in the
compensation box which allow to optimise their hf behaviour.
This adjustment is a precondition for achieving the maximum
bandwidth with probe and a minimum of pulse aberrations.
This adjustment requires a calibrator with a short rise time (typ.
4 ns) and a 50 Ω output, a frequency of 1 MHz, an amplitude
of 0.2 V
requirements.
Connect the probe to the scope input to which it is to be adjusted.
Select the PROBE ADJ. signal 1 MHz. Select dc coupling and
5 mV/cm with VOLTS/DIV. and 0.1 μs/cm with TIME/DIV., both
calibrated. Insert the probe tip into the calibrator output connector. The screen should show the signal, rise and fall times will
be visible. Watch the rising portion and the top left pulse corner,
consult the manual for the location of the adjustments.
. The PROBE ADJ. output of the scope fulfi ls these
PP
Operating modes of the vertical amplifi er
The controls most important for the vertical amplifi er are:
VERT/XY
containing the operating modes and the parameters of the
individual channels.
Changing the operating mode is described in the chapter:
”Controls and Readout“.
Remark: Any reference to ”both channels“ always refers to
channels 1 and 2.
Usually oscilloscopes are used in the Yt mode. In analog mode
the amplitude of the measuring signal will defl ect the trace
vertically while a time base will defl ect it from left to right.
The vertical amplifi ers offer these modes:
– One signal only with CH1.
– One signal only with CH2.
– Two signals with channels 1 and 2 (DUAL trace mode)
In DUAL mode both channels are operative. In analog mode
the method of signal display is governed by the time base (see
also ”Controls and Readout“). channel switching may either
take place after each sweep (alternate) or during sweeps with
a high frequency (chopped).
The normal choice is alternate, however, at slow time base settings the channel switching will become visible and disturbing,
when this occurs select the chopped mode in order to achieve
a stable quiet display.
, CH1 , CH2 . They give access to the menus
incorrect correct incorrect
The criteria for a correct adjustment are:
– short rise time, steep slope.
– clean top left corner with minimum over- or undershoot,
fl at top.
After adjustment check the amplitude which should be the
same as with 1 kHz.
It is important to fi rst adjust 1 kHz, then 1 MHz. It may be necessary to check the 1 kHz adjustment again.
Please note that the calibrator signals are not calibrated with
respect to frequency and thus must not be used to check the
time base accuracy, also their duty cycle may differ from 1:1.The
probe adjustment is completed if the pulse tops are horizontal
and the amplitude calibration is correct.
In DSO mode no channel switching is necessary as each input
has its own A/D converter, signal acquisition is simultaneous.
In ADD mode the two channels 1 and 2 are algebraically added (±CH1 ±CH2). With + polarity the channel is normal, with
– polarity inverted. If + Ch1 and – CH2 are selected the difference
will be displayed or vice versa.
Same polarity input signals:
Both channels not inverted: = sum
Both channels inverted: = sum
Only one channel inverted: = difference
Opposite polarity input signals:
Both channels not inverted: = difference
Both channels inverted: = difference
One channel inverted: = sum.
Please note that in ADD mode both position controls will be
operative. The INVERT function will not affect positioning.
Often the difference of two signals is to be measured at signal
take-offs which are both at a high common mode potential.
While this one typical application of the difference mode one
important precaution has to be borne in mind: The oscilloscope vertical amplifi ers are two separate amplifi ers and do not
constitute a true difference amplifi er with as well a high CM
rejection as a high permissible CM range! Therefore please
observe the following rule: Always look at the two signals in
the one channel only or the dual modes and make sure that
they are within the permissible input signal range; this is the
case if they can be displayed in these modes. Only then switch
to ADD. If this precaution is disregarded grossly false displays
Subject to change without notice
13
Operating modes of the vertical amplifier
may result as the input range of one or both amplifi ers may
be exceeded.
Another precondition for obtaining true displays is the use of
two identical probes at both inputs. But note that normal probe
tolerances (percent) will cause the CM rejection to be expected
to be rather moderate. In order to obtain the best possible results proceed as follows: First adjust both probes as carefully
as possible, then select the same sensitivity at both inputs and
then connect both probes to the output of a pulse generator
with suffi cient amplitude to yield a good display. Readjust one
(!) of the probe adjustment capacitors for a minimum of overor undershoot. As there is no adjustment provided with which
the resistors can be matched a residual pulse signal will be
unavoidable.
When making difference measurements it is good practice
to fi rst connect the ground cables of the probes to the object
prior to connecting the probe tips. There may be high potentials
between the object and the scope. If a probe tip is connected
fi rst there is danger of overstressing the probe or/and the scope
inputs! Never perform difference measurements without both
probe ground cables connected.
XY operation
This mode is accessed by VERT/XY > XY. In analog mode
the time will be turned off. The channel 1 signal will defl ect in X
direction (X-INP. = horizontal input), hence the input attenuators,
the variable and the POSITION 1 control will be operative. The
HORIZONTAL control will also remain functional.
Channel 2 will defl ect in Y direction.
Please note:
– As the trigonometric functions are
periodic limit the calculation to
angles <90 degrees. This is where
this function is most useful.
– Do not use too high frequencies,
because, as explained above, the
two amplifi ers are not identical,
their phase difference increases with frequency. The spec
gives the frequency at which the phase difference will stay
<3 degrees.
– The display will not show which of the two frequencies does
lead or lag. Use a CR combination in front of the input of the
frequency tested. As the input has a 1 MΩ resistor it will be
suffi cient to insert a suitable capacitor in series. If the ellipse
increases with the C compared to the C short-circuited the
test signal will lead and vice versa. This is only valid <90
degrees. Hence C should be large and just create a barely
visible change.
If in XY mode one or both signals disappear, only a line or a point
will appear, mostly very bright. In case of only a point there is
danger of phosphor burn, so turn the intensity down immediately; if only a line is shown the danger of burn will increase the
shorter the line is. Phosphor burn is permanent.
a
sin ϕ =
b
a
cos ϕ = 1 – (—
b
a
ϕ = arc sin
b
—
2
)
—
Measurement of phase differences in dual channel
Yt mode
Please note: Do not use ”alternate trigger“ because the time
differences shown are arbitrary and depend only on the respective signal shapes! Make it a rule to use alternate trigger only
in rare special cases.
The x 10 magnifi er will be inoperative in XY mode. Please note
the differences in the Y and X bandwidths, the X amplifi er has
a lower – 3 dB frequency than the Y amplifi er. Consequently
the phase difference between X and Y will increase with frequency.
In XY mode the X signal (CH1 = X-INP). can not be inverted.
The XY mode may generate Lissajous fi gures which simplify
some measuring tasks and make others possible:
– Comparison of two signals of different frequency or adju-
stment of one frequency until it is equal to the other resp.
becomes synchronized.
– This is also possible for multiples or fractions of one of the
frequencies.
Phase measurements with Lissajous fi gures
The following pictures show two sine waves of equal amplitude
and frequency but differing phase.
ab
0° 35° 90° 180°
Calculation of the phase angle between the X- and Y-signals (after reading a and b off the screen) is possible using the following
formulas and a pocket calculator with trigonometric functions.
This calculation is independent of the signal amplitudes:
The best method of measuring time or phase differences is using
the dual channel Yt mode. Of course, only times may be read off
the screen, the phase must then be calculated as the frequency
is known. This is a much more accurate and convenient method
as the full bandwidth of the scope is used, and both amplifi ers
are almost identical. Trigger the time base from the signal
which shall be the reference. It is necessary to position both
traces without signal exactly on the graticule center (POSITION
1 and 2). The variables and trigger level controls may be used,
this will not infl uence the time difference measurement. For
best accuracy display only one period at high amplitude und
observe the zero crossings. One period equals 360 degrees.
It may be advantageous to use ac coupling if there is an offset
in the signals.
t = horizontal spacing of the
zero transitions in div
T= horizontal spacing for one
period in div
In this example t = 3 cm and T = 10 cm, the phase difference in
degrees will result from:
5 3
ϕ° =
—
T 10
or in angular units:
t 3
arc ϕ° =
T 10
· 360° = — · 360° = 108°
—
· 2π = — · 2π = 1,885 rad
14
Subject to change without notice
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