Hameg HM604 Service manual
Table of contents
Technical Data
Accessories .....................
Operating Instructions
General Information
Use of tilt handle
Safety.
Operating conditions
Warranty
Maintenance
Mains/Line voltage change
Type of Signal
Amplitude Measurements
Time Measurements
Connection of Test Signal
Operating
First Time Operation
Trace Rotation TR
DC Balance Adjustment
Use and Compensation of Probes
Operating Modes of the Y Amplifier
X-Y Operation
X-Y Phase Measurements
Dual Trace Phase Difference Measurements
Measurement of an amplitude modulation
Triggering and
Triggering of video signals
Function of variable HOLD OFF control
Sweep Delay /After Delay Triggeringe
Delay Mode Indication
Component Tester
Miscellaneous
Test Patterns
Short Instruction
Front Panel Elements
Folder with Front View
Test Instructions
General
Cathode-Ray Tube: Brightness, Focus,
Astigmatismus Check
Symmetry and Drift of
Calibration of the Vertical Amplifier
Transmission Performance of the Vertical Amplifier
............................T2
Operating Modes: CH I/II-TRIG.
Triggering Checks
Timebase
SweepDelay
Component Tester
Trace Alignment
Miscellaneous
....................
.................
......................
.....................
...................
...................
.....................
.................
...................
Timebase
................
..................
...................
.......................
Linearity, Raster Distortions . T 1
CHOP., INV. l/II and XY-Betrieb . T 2
.................
......................
....................
.................
..................
...................
...............
................
............
............
...............
............
...............
.............
............
.............
............
..............
..............
...............
thevertical
........
.......
......
......
Amplifier
.........
l/II,
DUAL, ADD,
....
. .
....
M 10
P
1
Z 1
M 1
M 1
M 1
M 2
M 2
M 2
M 2
M 3
M 3
M 4
M 5
M 6
M 7
M 7
M 7
M 8
M 9
Ml 0
Ml 0
Ml 1
Ml 1
Ml 2
Ml3
Ml 3
Ml 5
Ml 5
Ml 7
Ml 8
K 1.
K
2
T 1
T 1
T 1
T 1
T 3
T 3
T 4
T 4
T 4
T 4
Oscilloscope
HM 604
Service Instructions
General .......................S 1
Instrument Case Removal ............. S 1
Operating Voltages ................. S 1
Minimum Brightness ................ S 1
Astigmatismus control ............... S 1
Trouble Shooting the Instrument ..........S 2
Replacement of Components and Parts ......S 2
Replacement of the Power Transformer ......S 2
Adjustments ....................S 3
Circuit Diagrams
Block Diagram
Wiring Diagram
Identification of Components
Y Input, Attenuator, Preamplifier CH.
Y intermediate Amplifiers, Trigger Pre-Amplifiers,
Component Tester
Y Final Amplifier
Post Trigger, Field Selector
Timebase (analog)
Timebase
Tim,ebase Generator
X Final Amplifier, Calibrator
CRT and HV circuit
Power Supply
Component Locations
XY Board
TB Board
PTFS Board
TBG, CAL, YF Boards
CO, EY, Z Boards
...................
...................
..................
(digital)
..................
....................
......................
......................
.....................
..................
................
.............
.................
................
.............
.................
................
............
l/II
......
D 1
D 2
D 3
D 4
D 5
D 6
D 7
D 8
D 9
DlO
Dl
D12
D13
D14
D15
D16
D17
D18
1
Subject to change without notice
9.88. 604
Specification
Vertical
Operating modes: Channel I or Ch. II separate,
Channel I and II: alternate or chopped.
(Chopper frequency approx.
Sum or difference of Ch. I and Ch. II,
(with invert buttons for both Channels).
XY-Mode: via Channel I and Channel II.
Frequency range: 2x DC to 6OMHz (- 3dB).
Risetime: approx. 5.8ns. Overshoot: II %.
Deflection coefficients: 12 calibrated steps
from 5 mV/div. to
variable 2.5: 1 to min.
Accuracy in calibrated position:
Y-Magnification x5 (calibrated) to 1 mV/div.
(Frequency range DC to
input impedance: 1 MQ II
Input coupling: DC-AC-GD (Ground)
Input voltage: max. 400V (DC + peak AC).
Y-output from CH I or CH II, = 50
Delay Line: approx. 90ns.
Mhtion
ZOV/div
50V/cm.
0.5MHz).
in l-Z-5 sequence,
+3%.
20MHz. -
3OpF.
3dB.
mV,Jdiv.
(50
Trigger System
With automatic
normal with level control from DC- 100 MHz.
LED indication for trigger action.
Slope: positive or negative.
Sources: Ch. I, Ch. II, line, external.
Coupling: AC (21
Threshold: external
Active TV-Sync-Separator for line and frame.
Slope positive or negative.
2nd. Triggering
trolled (independent from slope direction).
+ selection for TV mode.
Threshold: 1 div; typlcal
Trigger bandwidth:
lOHz-IOOMHz (P5mm
OHz
LF
HF(?50kHzmlOOMHz).
to approx. 20 MHz), DC
(DC -
550 kHz),
r50mV.
(Del. Trig.):
0.5div.
225
Hz to 60 MHz.
autom. or slope con-
height)
52)
60 MHz Universal Oscilloscope
2 Channels, 1
Timebase: 2.5s/div. to 5ns/div. including
Triggering:
mV/div.
DC-lOOMHz,
Sensitivity, Delay Line, Component Tester
x10
Magnifier&Sweep Delay
TV Sync Separator, After-Delay Trigger
Time coefficients: 23 calibrated steps
from
50ns/div.
variable 2.5: 1 to min.
accuracy in calibrated position:
with X-Magnifier
Hold-Off time: variable (2 5 : 1).
Delay: 7 decade steps
from 1 OOns
Bandwidth X-Amplifier:
Input X-Amplifier via Channel
sensitivity see Ch. II specification.
X-Y phase shift:
Ramp output: approx 5V. positive going
Test voltage: max.
Test current: max.
Test frequency: 50 - 60 Hz (line frequency).
Cathode-ray tube:
rectangular screen, internal graticule 8x10 cm.
Total acceleration voltage: 12
Trace rotation: adjustable on front panel.
Calibrator: square-wave generator switchable
from
Output voltage: 0.2V and 2V fl
Protective system Safety Class I
Linevoltage: 110. 125, 220,
Line frequency: 50 to 60Hz.
Power consumption: = 40 Watt.
Weight: approx. 8kg. Colour: techno-brown.
Cabinet: W 285, H 145, D 380mm.
Lockable tilt handle.
to 1
s/div
in l-2-5 sequence,
2.5s/div,
x10 (k
to 0.1 s, variable approx 10 : 1 to 1 s.
<3”
below 120
8.5V,,,
8mA,,,
150CTB31
=
1
kHz
to 1 MHz
+3%.
5%) to =
DC-5MHz (-3dB).
II,
(open circuit).
(shorted).
P43l123,
(t,
approx. 3ns).
24OV- *IO%.
5nsIdiv..
kHz.
kV.
%.
(IEC
348).
With its variety of operating and trigger modes, the HM604 is a new in-
novative general purpose oscilloscope satisfying a wide range of exacting re-
quirements in laboratory, production, and service. The dual-channel measure-
ment amplifier ensures highly faithful waveform transfer characteristics,
which can be readily checked on the built-in fast-risetime 1 MHz Calibrator
from probe tip to CRT screen! Using Y-axis magnification, the instrument’s
high sensitivity enables stable displays of very small signals as low as 0.5
mV.
An analog output is provided for connecting multimeters or counters. Another
important feature is the internal delay line for observations of the leading edge
of a signal. As in dual-time base oscilloscopes, the HM604 features a calibrated sweep delay mode, allowing smallest waveform sections to be expanded
up to 1000 times.
The
HM604’s
most outstanding feature, however, is the unique, newly
developed automatic After-Delay Trigger mode to ensure extremely stable
displays and jitter-free measurements of asynchronous signal sections and
bursts or pulse trains, independent of amplitude fluctuations. An active
TV-
Sync-Separator further enhances trigger quality of video frame and line signals. In the alternate trigger mode, two signals of different frequencies can be
compared.
With this state-of-the-art oscilloscope, HAMEG again sets a new price/
performance standard which is not likely to be met by others in this category.
Users will be particularly impressed by the instrument’s outstanding versatility
and ease of operation. These features are possible in the HM604 due to
HAMEG’s
meticulous attention to detail and many decades of successful
design experience.
-
Subject to change
without
notice
Test
Cable Banana - BNC
Coaxial test cable; length 1.15 m, characteristic impedance 5Ofi.
Cable capacitance
12OpF.
Input voltage max.
5OOV,.
HZ32
Modular Probes
The clear advantage over ordinary probes are field replaceable
parts and the HF-compensation feature on the 10: 1 attenuator pro-
bes For the first time, probes in this price range allow adjustments
of their HF-characteristics to match individually the input impedance of each scope. This is particularly important for scopes with
higher bandwidths (>SOMHz), as otherwise strong overshoot or
rounding may occur, when measuring fast-rising square waves.
An exact HF-compensation, however, is only possible with square-
wave generators having a
already feature such a calibration generator. For other oscillo-
scopes, it is available as accessory item
following Modular Probes are available (HZ36 without HF-com-
pensation):
risetime <5ns.
Most
HZ60-2.
HAMEG
scopes
At present the
Test Cable BNC-BNC
Coaxial test cable; length 1 m, characteristic impedance
Cable capacitance 126pF. Input voltage max.
5OOV,.
Adapter Banana - BNC
Two 4mm binding posts
male plug. input voltage max.
5Ofz
Through-Termination
For terminating systems with
Maximum load 2 W. Max. voltage 1
(19mm
between
5OOV,.
5OS2
centers)
characteristic impedance.
OV,,,.
HZ34
500.
HZ20
to standard BNC
HZ22
Carrying Cases
For HM 103
For HM203, HM204. HM205, HM208, HM408. HM604,
HM605 and HM 1005
Viewing Hood
For HM203, HM204, HM205, HM208, HM408, HM604, HM605
and HM 1005
Scope-T-tar
HZ95
HZ96
HZ47
HZtiOa
Type
Attenuation Ratio
Bandwidth min. (MHz)
Risetime
(ns)
Inp. Capacitance
Inp. Resistance (MR)
Inp. Voltage max.
Cable Length (m)
Spare Cable for HZ36
Spare Cable for HZ51, HZ54
Sparepart Kit (2 sprung
Special probe for AM-demodulation and wobbulator measure-
ments. HF-Bandwidth
age 250mV -
peak AC. Cable length 1.2m.
High
For measurement of voltages up to
approx. 500 mQ. Recommended load resistance1
(switchable). Attenuation ratio 1000 : 1. Bandwidth 1 MHz. Cable
length 1.5 m. BNC connector.
5OV,,,.
Vdtaget
HZ36
selectable
l:l/lO:l 1O:l
IO/
3513.5
(pF)
47/18
(V,)
hooks, 2 screw tips, 1 ground cable)
I’mbe
HZ51 HZ52 HZ53
IO:1
100
150
<2
16
l/10
600 600
1.5 1.2
IOOkHz
DC isolation Voltage 200V DC including
10
-5OOMHz
(HF) 1OO:l
250
tl.4
16
10 100
600 1200
1.5 1.5
(+ldB).
150
<2
65
AC
HZ54
selectable
1:1/10:1
IO/
150
35/<2
40/I
l/10
600
1.2
HZ39
HZ57
HZ46
InputVolt-
Hz58
15kV,,.
Input resistance
Ma/l
0
MQ
For Checking the Y amplifier, timebase, and compensation of all
probes, the
square-wave generator with switchable frequencies of DC, 1
IOOHz,
nals of 25
100x probes); accuracy +q %. Battery-powered.
8
I-IO-I
mV,,
HZ6O-2
is a crystal-controlled, fast rising (typ. 3ns)
OOkHz,
and 1 MHz. Three BNC outputs provide sig-
into 50 M,
0.25V,,
and
2.5V,,
(open circuit for 1 Ox and
Component-Tester
Indispensable for trouble-shooting in electronic circuits. Single
component and in-circuit tests are both possible. The HZ65 operates with all scopes, which can be switched to X-Y operation (ext.
horizontal deflection). Non-destructive tests can be carried out on
almost all semiconductors, resistors, capacitors, and coils. Two
sockets provide for quick testing of the 3 junction areas in any small
power transistor. Other components are connected by using 2
banana jacks. Test leads supplied.
Examples of Test Displays:
ShortcircuIt
Capacitor
33~F
Junction E-C Z-Diode
-lO-
HZ65
t8V
Printed in West Germany 5/90
Zl
Operating Instructions
General Information
This oscilloscope is easy to operate. The logical arrange-
ment of the controls allows anyone to become familiar with
the operation of the instrument after a short time, however,
experienced users are also advised to read through these
instructions so that all functions are understood.
Immediately after unpacking, the instrument should be
checked for mechanical damage and loose parts in the interior. If there is transport damage, the supplier must be informed immediately. The instrument must then not be put
into operation.
Check that the instrument is set to the correct mains/line
voltage. If not, refer to instructions on page M2.
Use of tilt handle
To view the screen from the best angle, there are three dif-
ferent positions (C, D, E) for setting up the instrument. If the
instrument is set down on the floor after being carried, the
handle remains automatically in the upright carrying posi-
tion (A).
In order to place the instrument onto a horizontal surface,
the handle should be turned to the upper side of the oscilloscope (C). For the D position
should be turned in the opposite direction out of the carry
ing position until it locks in place automatically underneath
the instrument. For the E position (20” inclination), the
handle should be pulled to release it from the D position and
swing backwards until it locks once more.
The handle may also be set to a position for horizontal carry-
ing by turning it to the upper side to lock in the B position. At
the same time, the instrument must be moved upwards,
because otherwise the handle will jump back.
B
6
(IO’
inclination), the handle
E
cict
20”
Safety
This instrument has been designed and tested in accordance with
Electronic Measuring Apparatus, and has left the factory
in a safe condition. The present instruction manual contains
important information and warnings which have to be followed by the user to ensure safe operation and to retain the
oscilloscope in safe condition. The case, chassis and all
measuring terminals are connected to the protective earth
contact of the appliance inlet. The instrument operates according to Safety C/ass I (three-conductor power cord with
protective earthing conductor and a plug with earthing contact). The mains/line plug shall only be inserted in a socket
outlet provided with a protective earth contact. The protective action must not be negated by the use of an extension
cord without a protective conductor.
Warning! Any interruption of the protective conductor
inside or outside the instrument or disconnection of the
protective earth terminal is likely to make the instru-
ment dangerous. Intentional interruption of the protec-
tive earth connection is prohibited. The mains/line plug
should be inserted before connections are made to
measuring circuits.
The grounded accessible metal parts (case, sockets, jacks)
and the mains/line supply contacts (line, neutral) of the in-
strument have been tested against insulation breakdown
with 2000 Vr.m.s.
Under certain conditions, 50 Hz or 60Hz hum voltages can
occur in the measuring circuit due to the interconnection
with other mains/line powered equipment or instruments.
This can be avoided by using an isolation transformer
(Safety Class II) between the mains/line outlet and the
power plug of the instrument. When displaying waveforms
where the “low-level” side of the signal is at a high potential, even with the use of a protective isolation transformer,
it should be noted that this potential is connected to the os-
cilloscope’s case and other accessible metal parts. High
voltages are dangerous. In this case, special safety precau-
tions are to be taken, which must be supervised
personnel if the voltage is higher than 42V.
Most cathode-ray tubes develop X-rays. However, the
dose equivalent rate falls far below the maximum per-
missible value of
Whenever it is likely that protection has been impaired, the
instrument shall be made inoperative and be secured
against any unintended operation. The protection is Ii kely to
be impaired if, for example, the instrument
-
shows visible damage,
-
fails to perform the intended measurements,
-
has been subjected to prolonged storage under un-
favourable conditions (e.g. in the open or in moist envi-
ronments),
-
has been subject to severe transport stress (e.g. in poor
packaging).
IECPublication346,SafetyRequirementsfor
(5OHz).
by qualified
36pA/kg (0.5mRlh).
Subject to change without notice
Ml
Operating conditions
Maintenance
The instrument has been designed for indoor use.
The permissible ambient temperature range during operation is + 15°C
. . .
+3O”C. It may occasionally be subjected to
temperatures between + 10°C and - 10°C without degrad-
ing its safety. The permissible ambient temperature range
for storage or transportation is -40°C .
+70X.
The maximum operating altitude is up to 2200m (non-
operating 15000m). The maximum relative humidity is up
to 80%.
If condensed water exists in the instrument it should be
acclimatized
before switching on. In some cases (e.g.
extremely cold oscilloscope) two hours should be allowed
before the instrument is put into operation. The instrument
should be kept in a clean and dry room and must not be
operated in explosive, corrosive, dusty, or moist environ-
ments The oscilloscope can be operated in any position,
but the convection cooling must not be impaired. The
wen-
tilation holes may not be covered. For continuous operation the instrument should be used in the horizontal position, preferably tilted upwards, resting on the tilt handle.
The specifications stating tolerances are only valid if
the instrument has warmed up for 30 minutes at an
ambient temperature between
+15C”
and +3OC9 Values not stating tolerances are typical for an average
instrument.
Warranty
Each instrument runs through a quality test with 10 hour
burn-in before leaving the production. Practically every early
failure is detected in intermittent operation by this method.
However, it is possible that a component fails only after a
lengthy operating period. Therefore a functional guaran-
tee of 2 years is given for all units. The condition for this is
that no modifications have been made in the instrument. In
the case of shipments by post, rail or carrier it is recom-
mended that the original packing is carefully preserved.
Transport damages and damage due to gross negligence
are not covered by the guarantee.
In the case of a complaint, a label should be attached to the
housing of the instrument which describes briefly the faults
observed. If at the same time the name and telephone
number (dialing code and telephone or direct number or
department designation) is stated for possible queries, this
helps towards speeding up the processing of guarantee
claims.
Various important properties of the oscilloscope should be
carefully checked at certain intervals. Only in this way is it
largely certain that all signals are displayed with the accuracy on which the technical data are based. The test
methods described in the test plan of this manual can be
performed without great expenditure on measuring instruments. However, purchase of the new HAMEG scope tester HZ 60, which despite its low price is highly suitable for
tasks of this type, is very much recommended.
The exterior of the oscilloscope should be cleaned regularly
with a dusting brush. Dirt which is difficult to remove on the
casing and handle, the plastic and aluminium parts, can be
removed with a moistened cloth (99% water +I % mild
detergent). Spirit or washing benzine (petroleum ether) can
be used to remove greasy dirt. The screen may be cleaned
with water or washing benzine (but not with spirit (alcohol)
or solvents), it must then be wiped with a dry clean lint-free
cloth. Under no circumstances may the cleaning fluid get
into the instrument. The use of other cleaning agents can
attack the plastic and paint surfaces.
Switching over the mains/line voltage
The instrument is set for 220V (240V U.K.) line voltage on
delivery. It can be switched over to other voltages at the
fuse holder combined with the 3-pole appliance inlet at the
rear of the instrument. Firstly the fuse holder printed with
the voltage values is removed using a small screw driver
and - if required - provided with another fuse. Refer to the
table below for the prescribed value of the fuse. Then
replace the fuse holder so that the impressed white triangle
points to the desired voltage. Here pay attention that the
cover plate is also correctly engaged. The use of repaired
fuses or short circuiting the fuse holder is not allowed. Damage arising because of this is not covered by the guarantee.
Fuse type: Size 5 x 20 mm; 250 V-, C;
IEC 127, Sheet III; DIN 41 662 (possibly DIN
sheet 3).
Cutoff: time lag
Line voltage
llOV-flO%
125V- &IO%
22ov- &IO%
24OV- &IO%
(T).
Fuse rating
TO.63 A
TO.63 A
T0.315A
T0.315A
.41
571
M2
Subject to change
wlthout
notice
Type of Signal
All types of signals with a frequency spectrum below
60 MHz can be displayed on the HM 604. The display of sim-
ple electrical processes such as sinusoidal RF and AF signals or ripple poses no problems. However, when square or
pulse-shaped signals are displayed it must be remembered
that their harmonic content must also be transmitted. In
this case, the bandwidth of the vertical amplifier must be
considerably higher than the repetition frequency of the sig-
nal. In view of this, accurate evaluation of such signals with
the HM 604 is only possible up to a maximum repetition rate
of
6MHz.
Operating problems can sometimes occur when
composite signals are to be displayed, especially if they do
not contain any suitable level components and repetition
frequency which can be used for triggering. This occurs, for
example, with burst signals. To obtain a stably triggered display in these cases, it may be necessary to use Normal Triggering, HOLD OFF time control, and/or
control.
TIME/DIV.
variable
If a sinusoidal waveform, displayed on the oscilloscope screen, is to be converted into an effective (rms) value, the resulting peak-to-peak value must be divided by
2x-
=
2.83. Conversely, it should be observed that sinusoidal voltages indicated in
V,,,
(V,,,)
have 2.83 times the potential difference in V,,. The relationship between the different voltage magnitudes can be seen from the following figure.
Voltage values of a sine curve
v
= effective value;
rms
V,,
= peak-to-peak value;
V,
= simple peak or crest value;
V,,,
= momentary value.
Video signals are easily triggerable by the aid of the active
TV sync separator (TV SEP. switch).
For optional operation as a DC or AC voltage amplifier, each
channel is provided with a DC-AC coupling switch. The DC
position should only be used with an attenuator probe or at
very low frequencies or if the determination of DC voltage
content of the signal is absolutely necessary.
However, when investigating very low-frequency pulses,
misleading ramp-offs may occur with AC coupling. In this
case, DC operation is to be preferred if the signal voltage is
not superimposed on a too high DC voltage level. Otherwise, a capacitor of adequate capacitance must be con-
nected before the input of the vertical amplifier (switched to
DC coupling). It should be remembered that this capacitor
must have a sufficiently high breakdown voltage. DC opera-
tion is also recommended for the display of logic and pulse
signals, particularly if their pulse duty factor changes perma-
nently during operation. Otherwise, the display will move
up and down with any change. DC voltages can only be
measured in the DC position.
Amplitude Measurements
The minimum signal voltage required at the vertical amplifier
input for a display of 1 cm is approximately
achieved with the attenuator control set at
7mV,,.
5mV/cm,
This is
its var-
iable control in the fully clockwise position and pulled
out. However, smaller signals than this may also be dis-
played. The deflection coefficients on the input attenuators
are indicated in
mV/cm
or V/cm (peak-to-peak value).
The magnitude of the applied voltage is ascertained by
multiplying the selected deflection coefficient by the
vertical display height in cm.
If an attenuator probe x 70 is used, a further multiplication by a factor of 70 is required to ascertain the correct
voltage value.
For exact amplitude measurements the variable con-
trol on the attenuator switch must be set to its calibra-
ted detent CAL. When turning the variable control ccw
the sensitivity will be decreased by a factor of 2.5.
Therefore every intermediate value is possible within
the 7-2-5 sequence.
With direct connection to the vertical input, signals up to
4OOV,, may be displayed (attenuator set to
ZOV/cm,
variable control ccw).
When pulling the variable control knob (MAG x5), the sen-
sitivity is increased by a factor of 5. Hence follows a min. deflection coefficient of 1
mV/cm
(reduced bandwidth).
In general electrical engineering, alternating voltage data
normally refers to effective values (rms = root-mean-
square value). However, for signal magnitudes and voltage
designations in oscilloscope measurements, the peak-to-
peakvoltage (V,,) value is applied. The latter corresponds to
the real potential difference between the most positive and
most negative points of a signal waveform.
Subject to change without notice
With the designations
H = display height in cm,
= signal voltage in
U
V,,
at the vertical input,
D = deflection coefficient in V/cm at attenuator switch,
the required quantity can be calculated from the two given
quantities:
=
D-H
U
H=;
D+
M3 604
However, these three values are not freely selectable. They
have to be within the following limits (trigger threshold, ac-
curacy of reading):
H between 0.5 and
U between 1
D between
5mV/cm
D between 1 mV/cm and
(with
pulled MAG x5 knob). As a rule, all signals to be displayed are periodically repeat-
mV,,
and 16OV,,,
8cm,
if possible 3.2 to
and
20V/cm
4V/cm
8cm,
in l-2-5 sequence.
in l-2-5 sequence
Examples:
Set deflection coefficient D = 50 mV/cm 2 0.05 V/cm,
observed display height H = 4.6 cm,
required voltage U =
Input voltage U =
5V,,,
0.05.4.6
= 0.23 V,,.
set deflection coefficient D = 1 V/cm,
required display height H = 5: 1 = 5cm
Signal voltage U =
22OV,,;2.fl=
622
V,,
(voltage > 16OV,,, with probe X 10 : U = 62.2 V,,),
desired display height H = min.
3.2cm,
max.
8cm.
max. deflection coefficient D = 62.2 : 3.2 = 19.4V/cm,
min. deflection coefficient D = 62.2 : 8 = 7.8V/cm,
adjusted deflection coefficient D =
If
the applied signal is superimposed on a DC (direct
lOV/cm
voltage) level the total value (DC + peak value of the alternating voltage) of the signal across the Y-input must
not exceed
*4OOV(see
figure). This same limit applies to
normal x 10 attenuator probes, the attenuation ratio of
which allows signal voltages up to approximately 1
to be evaluated. Voltages of up to approximately
,OOOV,,
2,4OOV,,
may be measured by using the HZ53 high voltage probe
which has an attenuation ratio of 100: 1. It should be noted
that its AC
peakvalue
is derated at higher frequencies. If a
normal x 10 probe is used to measure high voltages there is the
risk that the compensation trimmer bridging the attenuator
series resistor will break down causing damage to the input
of the oscilloscope. However, if for example only the residual ripple of a high voltage is to be displayed on the oscil-
loscope, a normal x 10 probe is sufficient. In this case, an appropriate high voltage capacitor (approx. 22-68nF) must be
connected in series with the input tip of the probe.
Voltage
’
DC +
AC,,,k
=
I
peak
F@u
AC
DC
DC
.-
/\
/
/
I
Total value of input voltage ’ -
The dotted line shows a voltage alternating at zero volt level. When superim-
posed a DC level, the addition of the positive peak and the DC voltage results
in the max. voltage (DC + AC,,,,).
4OOV,,,.
-.
-1
/
‘\
AC
\
\.
\
1
1’
/
!
/
’
\
\
Time
\
\
‘\
\
\
/
\,
It is very important that the oscilloscope input coupling is
set to DC, if an attenuator probe is used for voltages higher
than 400V (see page M6: Connection of Test Signal).
Time Measurements
ing processes and can also be designated as periods. The
number of periods per second is the recurrence frequency
or repetition rate. One or more signal periods or even part of
a period may be shown as a function of the adjustment of
the
TIMEIDIV.
DIV. switch are indicated in s/cm,
cordingly, the dial is subdivided into three sectors. The duration of a signal period or a portion of the waveform is
ascertained by multiplying the relevant time (horizon-
tal distance in cm) by the time coefficient selected on
the
TIME/DIV.
knob on the
detent CAL. for accurate measurement (arrow horizontal
and pointing to the right).
With the designations
L
= displayed wave length in cm of one period,
T = time in seconds for one period,
F
= recurrence frequency in Hz of the signal,
T,
= time coefficient in s/cm on
and the relation F =
stated
:
T =
L.T,
F
-
=
L.Tc
With X-MAG.
be divided by 10.
However, these four values are not freely selectable. They
have to be within the following’limits:
L
between 0.2 and 1 Ocm, if possible 4 to 1 Ocm,
T between 5 ns and 1 OS,
F
between 0.1 Hz and 60 MHz,
T,
between
(with X MAG. x 10
T,
between 5 ns/cm and
(with pushed X MAG.
Examples:
Displayed wavelength L = 7 cm,
set time coefficient T, = 0.5 ps/cm,
required period T =
c
required rec. freq. F = 1:(3.5.1
/
Signal period T =
set time coefficient T, = 0.2 s/cm,
required wavelength L = 0.5 : 0.2 =
switch. The time coefficients on the TIME/
ms/cm,
and ps/cm. Ac-
switch. The time variable control (small
TIME/DIV.
switch) must be in its calibrated
timebase
l/T,
the following equations can be
1
L
xl0
button depressed the T, value must
50ns/cm
and 1 s/cm in l-2-5 sequence
=
1
F.Tc
in out position), and
lOOms/cm
x10
7.0.5.1
in l-2-5 sequence
button).
O-” =
3.5~s
OP6)
= 286
0.5s,
2.5cm.
switch
kHz.
T,
T,
=
=
;
&
.
M4 604
Subject to change without notice
Displayed ripple wavelength L = 1 cm,
set time coefficient T, = 10 ms/cm,
required ripple freq. F = 1 : (1 .10.10-3) = 100Hz.
If magnification is used, this product must be divided by 10.
The
fall
time of a pulse can also be measured by using this
method.
TV-line frequency F = 15 625 Hz,
set time coefficient T, = 10 @cm,
required wavelength L = 1: (15 625.1
Sine wavelength L = min.
Frequency F = 1
max. time coefficient T, = 1 :
min. time coefficient T, = 1
set time coefficient T, = 0.2
required wavelength L = 1: (1
Displayed wavelength L =
set time coefficient T, = 0.5
pressed MAG X 10 button: T, = 0.05
required rec. freq. F = 1: (0.8.0.05.1
required period T = 1: (25.1
If the time is relatively short as compared with the complete
signal period, an expanded time scale should always be
applied (X MAG
tained time values have to be divided by
intervals at optional points of the signal can be measured
more exactly with the aid of the sweep delay. With it, the
display and measurement of time intervals, which are smal-
ler than 1 % of the full signal period, are possible. The smallest measurable time interval is, on the whole, dependent on
the obtainable brightness of the CRT. The limit is an expansion of approximately 1000 times. Using a Viewing Hood
HZ47, more expansion is possible, provided that the time
coefficient set on the
S@cm
basic period. Otherwise, the fastest sweep speed deter-
mines the greatest possible expansion.
When investigating pulse or square waveforms, the critical
feature is the
transients, ramp-offs, and bandwidth limits do not unduly
influence the measuring accuracy, the
measured between 10% and 90% of the vertical pulse
height. For peak-to-peak signal amplitude of
which are symmetrically adjusted to the horizontal center
line, the internal graticule of the CRT has two horizontal dotted lines
tenuator switch with its variable control together with the
Y-POS. control so that the pulse height is precisely aligned
with the 0 and 100 % lines. The 10 % and 90 % points of the
signal will now coincide with the two lines, which have a
distance of
additional subdivision of
the product of the horizontal distance in cm between
these two coincidence points and the time coefficient
setting.
(and using the X MAG x 10 facility) for the signal’s
risetime
&2.4cm
f2.4cm
kHz,
x10
from the center line. Adjust the Y at-
4cm,
max. 1 Ocm,
(4.1 03)
:(I O-1 03)
ms/cm,
03-
0.8cm,
ys/cm,
06)
= 40 ns.
button pushed). In this case, the ascer-
TIME/DIV.
of the voltage step. To ensure that
from the horizontal center line and an
0.2cm.
The
0p5)
=
6.4cm.
=
0.25ms/cm,
= 0.1
m&m,
0.2 - 1
0p3)
= 5cm.
@cm,
Ov6)
= 25 MHz,
70.
Very small time
switch is greater than
risetime
risetime
is generally
6cm
height,
is given by
100%
90%
-I
qot t-
The above figure shows correct positioning of the oscilloscope trace for accurate
With a time coefficient of O.O5ys/cm and pushed X MAG
x10
button the example shown in the above figure results
in a measured total
ttor
=
1.6cm.O.O5@cm:
When very fast risetimes are being measured, the rise-
times of the oscilloscope amplifier and the attenuator probe
have to be deducted from the measured time value. The
risetime
formula.
In this
of the oscilloscope amplifier (approx. 5.8ns), and t, the
risetime
then t,,, can be taken as the
lation is unnecessary.
Calculation of the example in
signal
of the signal can be calculated using the following
t,
=
v
ttot2 - t
ttot
is the total measured risetime,
of the probe (e.g. = 2 ns). If
risetime
t,
= V 8* -
risetime
risetime
2 -
osc
5.8* - 2*
measurement.
of
10 = 8ns
t
2
P
to,,
is the
ttot
is greater than 42 ns,
risetime
= 5.1 ns
of the pulse, and calcu-
tie
figure above results in a
risetime
Connection of Test Signal
Caution: When connecting unknown signals to the oscillo-
scope input, always use automatic triggering and set the
DC-AC input coupling switch to AC. The attenuator switch
should initially be set to POV/cm.
Sometimes the trace will disappear after an input signal has
been applied. The attenuator switch must then be turned
back to the left, until thevertical signal height is
With a
probe must be inserted before the oscilloscope’s vertical
input. If, after applying the signal, the trace is nearly
blanked, the period of the signal is probably substantially
signa!
amplitude greater than 16OV,,, an attenuator
only3-8cm.
Subject to change
wlthout
notlce
longer than the set value on the
should be turned to the left to an adequately greater time
coefficient.
The signal to be displayed should be fed to the vertical input
of the oscilloscope by means of a shielded test cable, e.g.
the HZ32 or HZ34, or by a x 10 or x 100 attenuator probe.
The use of these shielded cables with high impedance cir-
cuits is only recommended for relatively low frequencies
(up to approx. 50kHz). For higher frequencies, and when
the signal source is of low impedance, a cable of matched
characteristic impedance (usually
In addition, and especially when investigating square or
pulse waveforms, a resistor equivalent to the characteristic
impedance of the cable must also be connected to the cable
directly at the input of the oscilloscope. When using a 509
cable, such as the HZ34, a
HZ22 is available from HAMEG. When investigating square
or pulse waveforms with fast risetimes, transient
phenomena on both the edge and top of the signal may become visible if the correct termination is not used. It must
be remembered that the
dissipate a maximum of 2 watts. This power consumption
is reached with 1
If a x 10 or x 100 attenuator probe is used, no termination is
necessary. In this case, the connecting cable is matched di-
rectly to the high impedance input of the oscilloscope.
When using attenuator probes even high internal imped-
ance sources are only slightly loaded by approximately
10 MQ I I 16 pF or 100 MQ I I7 pF respectively. Therefore,
when the voltage loss due to the attenuation of the probe
can be compensated by a higher sensitivity setting on the
HM 604, the probe should always be used. Also it should be
remembered that the series impedance of the probe provides a certain amount of protection for the input of the os-
cilloscope amplifier. It should be noted that all attenuator
probes must be compensated in conjunction with the oscil-
loscope (see: Probe Adjustment, page M8).
If a x IO or x 100 attenuator probe is used at voltages
higher than 400 V, the DC input coupling must always
be set. With AC coupling, the attenuation is frequency-de-
pendent, the pulses displayed can exhibit ramp-off, DC-volt-
age contents are suppressed - but loads the respective
input coupling capacitor of the oscilloscope. The electric
strength of which is maximum 400V (DC + peak AC). For
the suppression of unwanted DC voltages, a capacitor of
adequate capacitance and electric strength may be con-
nected before the input tip of the probe (e.g. for ripple
measurements).
It is important to remember that when low voltage signals
are being investigated the position of the ground point on
the test circuit can be critical. This ground point should always be located as close as possible to the measuring
point. If this is not done, serious signal deformation may
OV,,,
50R
5OQ
through-termination will only
or with
TIMEIDIV.
5OQ)
is recommended.
through-termination type
28V,,
sine signal.
switch. It
result from any spurious currents through the ground leads
or test chassis parts. This comment also applies to the
ground leads on attenuator probes which ideally should be
as short and as thick as possible. For connection of a probe
to a BNC socket, a BNC-adapter should be used. It forms
often a part of the probe accessory. Grounding and matching problems are then eliminated.
Hum or interference voltage appearing in the measuring circuit (especially with a small deflection coefficient) is possibly caused by multiple grounding, because equalizing currents can flow in the shielding of the measuring cables (voltage drop between non-fused earthed conductors of other
line powered devices, which are connected to the oscilloscope or test object, e.g. signal generators with anti-interference capacitors).
Operating
For a better understanding of these Operating Instructions
the front panel picture at the end of these instructions can
be unfolded for reference alongside the text.
The front panel is subdivided into three sections according
to the various functions. The INTENS., FOCUS and TR
(trace rotation) controls are arranged on the left directly
below the screen of the cathode-ray tube (CRT). Continuing
towards the right are the horizontal magnification button (X
MAG. x10), the switch for calibrator frequency selection
(1
kHz/l
MHz) and calibrator output sockets
(CAL.). The COMPONENT TESTER pushbutton and its
measuring socket are located on the right side.
The X-Section, located on the upper right, next to the screen,
contains the red POWER pushbutton and indicating LED, all
controls for
zontal trace position (X-POS.), sweep delay (DELAY), TV
separator (TV SEP.) together with the field select button
(FIELD
doff adjustment (HOLD OFF).
The lower Y-Section contains the controls for the vertical
deflection system. On the right and left in this section are located: vertical input connector, DC-AC-GD input coupling
slide switch, Y-POS. control, INVERT pushbutton, attenuator switch with variable control, and ground jack. All
these controls and connectors exist in duplicate for each of
the Channels I and II. Three pushbuttons for selecting the
operating mode are arranged below the attenuator
switches: CH
These are explained later.
The instrument is so designed that even incorrect operation
will not cause serious damage. The pushbuttons control
only minor functions, and it is recommended that before
commencement of operation all pushbuttons are in the
“out” position. After this the pushbuttons can be operated
depending upon the mode of operation required.
timebase
l/II),
the XYmode button (XV), and the knob for
l/II
(TIME/DIV.),
triggering (TRIG.), hori-
-TRIG l/II, DUAL and ADD.
0.2V/2V
hol-
M6 604
Subject to change without notice
The HM 604 accepts all signals from DC (direct voltage) up
to a frequency of at least
voltages the upper frequency limit will be
ever, in this higher frequency range the vertical display
height on the screen is limited to approx. 6cm. The time resolution poses no problem. For example, with 100 MHz and
the fastest adjustable sweep rate (5ns/cm), one cycle will
be displayed every 2cm. The tolerance on indicated values
amounts to
be measured can therefore be determined relatively accu-
rately. However, from approximately 25 MHz upwards the
measuring error will increase as a result of loss of gain. At
40MHz
11 % should be added to the measured voltage at this frequency. As the bandwidth of the amplifiers differ (normally
between 65 and 70 MHz), the measured values in the upper
limit range cannot be defined exactly. Additionally, as al-
ready mentioned, for frequencies above
dynamic range of the display height steadily decreases. The
vertical amplifier is designed so that the transmission performance is not affected by its own overshoot.
f3%
in both deflection directions. All values to
this reduction is about 10%. Thus, approximately
60MHz (-3dB).
For
80MHz.
60MHz
sinewave
How-
the
First Time Operation
Check that the instrument is set to the correct mains/
line voltage. (Refer to page
Before applying power to the oscilloscope it is recom-
mended that the following simple procedures are performed:
-
Check that all pushbuttons are in the out position, i.e. released.
-
Rotate the three variable controls with arrows to their
calibrated detent.
-
Set the variable controls with marker lines to their mid-
range position (marker lines pointing vertically).
-
The LEVEL control knob should be on its left stop (AT).
-
The three lever switches in the X-Section should be set
to their uppermost position.
-
Both input coupling slide switches for CH.1 and
the Y-Section should be set to the GD position.
Switch on the oscilloscope by depressing the red POWER
pushbutton. An LED will illuminate to indicate working
order. The trace, displaying one baseline, should be visible
after a short warm-up period of 10 seconds. Adjust
and X-POS. controls to center the baseline. Adjust
TENS. (intensity) and FOCUS controls for medium bright-
ness and optimum sharpness of the trace. The oscilloscope
is now ready for use.
If only a spot appears (CAUTION! CRT phosphor can be
damaged.), reduce the intensity immediately and check
that the X-Y pushbutton is in the released (out) position. If
the trace is not visible, check the correct positions of all
knobs and switches (particularly LEVEL knob in AT position
and DELAY MODE lever switch to OFF).
M2).
CH.11
Y-P0S.I
IN-
in
To obtain the maximum life from the cathode-ray tube, the
minimum intensity setting necessary for the measurement
in hand and the ambient light conditions should be used.
Particular care is required when a single spot is displayed, as a very high intensity setting may cause damage
to the fluorescent screen of the CRT. Switching the oscilloscope off and on at short intervals stresses the cathode of
the CRT and should therefore be avoided.
Trace Rotation TR
In spite of Mumetal-shielding of the CRT, effects of the
earth’s magnetic field on the horizontal trace position
cannot be completely avoided. This is dependent upon
the orientation of the oscilloscope on the place of work.
A centred trace may not align exactly with the horizon-
tal center line of the graticule. A few degrees of misalignment can be corrected by a potentiometer acessi-
ble through an opening on the front panel marked
TR.
DC Balance Adjustment
The vertical preamplifiers for
matched dual
After long periods of use the FET characteristics may
change which can alter the DC balance of the vertical
amplifier. A quick check of DC Balance can be made on each
channel by pulling the fine amplitude control MAG x5 and
pushing it back. If the trace moves from the vertical position
(up or down) more than 1 mm, the DC Balance will require
readjustment. This check should be made after a 20-minute
warm-up period.
FETs
connected as input source followers.
Adjustment procedure
The following instructions should be performed to obtain
the correct DC balance adjustment of both channels.
-
Remove all input cables and adjust oscilloscope controls
to display the baseline.
-
Center the baseline using Y-POS. and X-POS. controls.
-
Set attenuator switches to
switches to GD.
-
Release all pushbuttons in the Y-Section.
-
Place the oscilloscope so that it rests
right position) and locate DC balance adjustment potentiometer access holes - marked
CH.11 -
which are found underneath the instrument.
-
Insert a screwdriver (blade approx.
20 mm) in
is located behind the hole.
-
Pull and push the
just balance pot so that the baseline no longer moves up
or down. When the trace remains steady, correction of
CH.1
-
Depress CH I/II-TRIG.
procedure for
CH.1
hole. A plastic guide with slotted bottom
is completed.
CH.II.
CH.1
variable control MAG x5 and ad-
CH.1
and
CH.11
contain
5mV/cm
l/II
button. Repeat adjustment
and input coupling
firmlyon
CH.1
its back (up-
DC-BALANCE
3mm,
length min.
Subject to change without notice
M7 604
Use and Compensation of Probes
To
display an undistorted waveform on an oscilloscope, the
probe must be matched to the individual input impedance
of the vertical amplifier.
small insulated non-metallic screwdriver or trimming tool,
the trimmer has to be adjusted slowly until the tops of the
squarewave signal are exactly parallel to the horizontal
graticule lines. (See Fig. above for 1
amplitude shown should be 4cm + 1.2 mm (= 3 %), During
this adjustment, the signal edges will remain invisible.
The HM604’s built-in calibration generator provides a
squarewave signal with a very low
switch-selectable frequencies of approx.
at two output sockets below the CRT screen. One output
provides
0.2V,, *I
% for 10: 1 probes, and
present at the other, for 100: 1 probes.
risetime
1 kHz and 1
(<5ns), and
MHz
2V,,
+I % are
Adjustment at 1 MHz
Probes
They incorporate resonance deemphasizing networks
trimmer in conjunction with inductances and capacitors)
which permit - for the first time - probe compensation in
the range of the upper frequency limit of the vertical oscillo-
When the attenuator switches are set to 5mV/cm vertical
deflection coefficient, these calibration voltages correspond to a screen amplitude of
The output sockets have an internal diameter of
accommodate the internationally accepted shielding tube
diameter of modern
Modular
4cm.
Probes and F-series
4.9mm
slimline
probes. Only this type of construction ensures the
extremely short ground connections which are essential for
an undistorted waveform reproduction of non-sinusoidal
scope amplifier. Only this compensative adjustment
ensures optimum utilisation of the full bandwidth, together
with constant group delay at the high frequency end,
thereby reducing characteristic transient-distortion near the
to
leading signal edge (e.g. overshoot, rounding, ringing, holes
or bumps) to an absolute minimum.
Using the probes HZ51, 52, and 54, the full bandwidth of
the HM 604 can be utilized without risk of unwanted waveform distortion.
high frequency signals.
Prerequisite for this HF-adjustment is a squarewave
Adjustment at 1
The C-trimmer adjustment compensates the capacitive
loading on the oscilloscope input (approx.
HM604). By this adjustment, the capacitive division
assumes the same division ratio as the ohmic voltage
kHz
3OpF
with the
generator with fast
impedance (approx.
quency of approx. 1 MHz. The calibrator output of the
HM604 meets these requirements when the pushbutton
1 MHz is depressed.
divider to ensure an equal division ratio for high and low frequencies, as for DC. (For
set to 1: 1, this adjustment is neither required nor possible).
A baseline exactly parallel to the horizontal graticule lines is
a major condition for accurate probe adjustments. (See also
‘Trace Rotation
TR’,
Connect the probes (Types HZ51, 52, 53,
CH.1 input. All pushbuttons should be released (in the ‘out’
position), and all push-pull knobs pushed ‘in’. Set the input
coupling switch to DC, the attenuator switch to 5mV/cm,
and the
controls to CAL. position. Plug the probe tip into the appropriate calibrator output socket, i.e. IO:1 probes into the
0.2V
1
TIME/DIV.
socket, 100: 1 probes into the 2.OV socket.
kHz
incorrect correct
Approximately 2 complete waveform periods are displayed
on the CRT screen. Now the compensation trimmer has to
be adjusted. Normally, this trimmer is located in the probe
1: 1
page M7.)
switch to
probes or switchable probes
54,
or HZ37) to
0.2ms/cm,
and all variable
incorrect
Connect the probe
the calibrator pushbutton
should be released (‘out’ position). Set the input coupling
switch to DC, attenuator switch to
DIV. switch to 0.1
position.
Insert the probe tip into the output socket marked
waveform will be displayed on the CRT screen, with leading
and trailing edges clearly visible. For the HF-adjustment
now to be performed, it will be necessary to observe the ris-
ing edge as well as the upper left corner of the pulse top. To
gain access to the HF-compensation trimmer, the plastic
cover of the probe connecting box has to be slid off after
unscrewing the probe cable. The connecting boxes of the
HZ51 and HZ54 contain one R-trimmer screw, each, while
that of the HZ52 provides three. These R-trimmers have to
be adjusted in
top is as straight as possible. Overshoot or excessive round-
ing are unacceptable. This is relatively easy on the HZ51
and HZ54, but slightly more difficult on the HZ52. The rising
edge should be as steep as possible, with the pulse top
remaining as straight and horizontal as possible.
head. On the 100: 1 probe HZ53, however, it is located in
the connecting box at the other end of the cable. Using a
On the HZ52, each of the three trimmers has a clearly
kHz.)
The signal
HZ51,52,
and 54 will also allow for HF-adjustments.
risetime
(HZ51,52,
l&cm.
(typical 4ns). and low output
5OQ).
providing
or 54) to CH.1 input. Depress
1MHz.
Set all variable controls to CAL.
0.2V
and 2V at a fre-
All other pushbuttons
5mV/cm,
and TIME/
such a manner that the beginning of the pulse
0.2V.
(R-
A
M8 604
Subject to change without notice
defined area of influence on the waveform shape (see Fig.),
offering the added advantage of being able to ‘straighten
out’ waveform aberrations near the leading edge.
The adjustment sequence must be followed in the order
described, i.e. first at 1
frequencies should not be used for timebase calibrations.
The pulse duty cycle deviates from 1 : 1 ratio.
Adjustment points of the probes
HZ51, HZ54
Prerequisites for precise and easy probe adjustments, as
well as checks of deflection coefficients, are straight horizontal pulse tops, calibrated pulse amplitude, and
osc.
I
Tz (I+)
1
CAL.
potential at the pulse base. Frequency and duty cycle are
relatively uncritical.
(NF) T,
response,
generator outputs are of particular importance.
kHz,
then at 1 MHz. The calibrator
zero-
For interpretations of transient
fast pulse risetimes and low-impedance
(I-F) T,
T3 T, T,
T,_:
alters the middle frequencies
Ti: alters the leading edge
T,: alters the lower frequencies
T,
(NF) 1
-
IOnskm
-
HZ52
T, (LF)
After completion of the HF-adjustment, the signal
amplitude displayed on the CRT screen should have the
same value as during the 1
kHz
adjustment.
Probes other than those mentioned above, normally have a
larger tip diameter and may not fit into the calibrator outputs Whilst it is not difficult for an experienced operator to
build a suitable adapter, it should be pointed out that most
of these probes have a slower risetime with the effect that
the total bandwidth of scope together with probe may fall
far below that of the HM604. Furthermore, the
HF-adjust-
ment feature is nearly always missing so that waveform distortion can not be entirely excluded.
Providing these essential features, as well as switch-select-
able output-frequencies, the calibrator of the HM 604 can,
under certain conditions, replace expensive squarewave
generators when testing or compensating
wideband-
attenuators or -amplifiers. In such a case, the input of an
appropriate circuit will be connected to one of the
CAL.-out-
puts via a suitable probe.
The voltage provided at a high-impedance input (I
5OpF)
will correspond to the division ratio of the probe used
(10:
1 =
20mV,,,
Suitable probes are
For low-impedance inputs (e.g. 50
100:
HZ51,
1 =
also
20mV,,
52, 53, and 54.
Q),
from 2V output).
a 1: 1 probe can be
MSJ
II
15-
employed which, however, must be fully terminated with a
5052
through-termination. Suitable probe types are HZ50
and HZ54. The latter must be switched to the 1: 1 position,
and the HF-trimmer in the connecting box turned fullycoun-
terclockwise.
When connected to the
0.2V
CAL. socket, and using the
HZ50, this arrangement will provide approx. 40mV,, at
50Q circuit input, and approx.
24mV,,
if the HZ54 is used.
The voltages given here will have larger tolerances than 1 %
since operation of a 1: 1 probe together with a
5OQ
load is
very uncommon.
incorrect
Adjustment
1 MHz
Subject to change without notice
correct
incorrect
Using the 2V CAL. socket under similar conditions is only
possible with the HZ54 probe. The potential obtained at the
5OQ
input will then be approx.
190mV,,,
but with almost
twice the risetime. Accurate readings of the available input
voltage can be shown directly on the HM604 when con-
necting a
5OQ
through-termination between the BNC plug
of the probe and the input of the oscilloscope.
Operating Modes of the Y Amplifier
The required operating modes are selected on three
pushbuttons located in the Y-Section. For Mono operation
all pushbuttons should be in the out position, the instrument is then operating on Channel/only.
M9
604
For Mono operation with Channel
pushbutton has to be pressed. When the DUAL button is
depressed, the HM604 is in
mode, the channels are displayed consecutively (alternate
mode). This mode is not suitable for the display of very low
frequency signals
or jump. Under these conditions,
depressed additionally selecting chopped mode. In this
position, both channels then share the trace during each
sweep period. For the display of high frequency signals, the
type of channel switching selected is less important.
To select the add mode only the ADD button should be
depressed. The signals on both channels are then added
together. If in this mode one channel is inverted (pushbutton INVERT depressed), then the difference between the
two channels is displayed. For both of these operating
modes, the vertical position of the trace depends on the setting of the Y-POS. controls of both channels.
(<l kHz),
as the tracewill appear to flicker
II,
the CH
Dualchannel
the ADD
l/II
-TRIG.
operation. In this
button should be
l/II
nal frequencies up to 120
quency the inherent phase difference between the vertical
and horizontal system makes accurate measurements difficult. In this mode, one of the
horizontal deflection (X) while the other signal provides the
vertical deflection (Y).
0”
The phase angle between the two signals can be deter-
mined from the Lissajous pattern as follows:
cos
cp
35”
=
1/ I-@
kHz.
sin cp =
However, above this fre-
sinewave
signals provides
90” 180”
E
Differentialmeasurements
urement of the voltage drop across floating components
(both ends above ground). Two identical probes should be
used for both vertical inputs. Using a separate ground connection and notconnecting the probe or cable shields to the
circuit under test avoid ground loops (hum, common-mode
disturbances).
X-Y Operation
For X-Yoperation, the pushbutton in the X-Section marked
X-Y must be depressed. The X signal is then derived from
the
Channe///(HOR.
during X-Y operation is determined by the setting of
the Channel II input attenuator and variable control.
This means that the sensitivity ranges and input impedances are identical for both the X and Y axes. However, the
Y-POS.II
is taken over by the X-POS. control. It is important to note
that the X MAG.
the sweep, should not be operated in the X-Y mode. It
should also be noted that the bandwidth of the X amplifier
is approximately
phase difference between both axes is noticeable from
50
The Y-Input signal may be inverted by using the INVERT
(channel I) facility.
control is disconnected in this mode. Its function
kHz
upwards.
INP.). The calibration
x10
facility, normally used for expanding
5MHz
X-Y Phase Measurements
The X-Y phase measurement method can be used to meas-
ure the phase difference between two signals of the same ence signal occupies exactly 10 divisions (see next figure).
frequency. This provides a method of measurement for sig-
techniques allow direct meas-
ofthexsignal
(-3dB), and therefore an increase in
= arc sin
%J
This simple formula works for angles less than
independent from both deflection amplitudes on the
screen.
Caution!
If a single spot appears (both deflection voltages are missing)
reduce the intensity immediately, as a high intensity setting
may cause damage to the fluorescent screen of the CRT.
f
b
90”,
it is
Dual-Trace Phase Difference Measurements
Phase comparison between two signals of the same fre-
quency can be made using the dual-trace feature (DUAL
button depressed). This method of phase difference meas-
urement can be used up to the frequency limit of the vertical
system. To make the comparison, use the following procedure:
Set the Input Coupling switches to the same position, and
the CH. I/II-TRIG.
reference signal (Phase 0”) is connected. Select ALT. chan-
nel switching for frequencies above 1
frequencies below 1
time delay to connect the signals to the input connectors.
Set the Input Attenuator switches and the CH I and CH II var-
iable controls so that the displays are approximately equal
and about five divisions in amplitude. Set the TIME/DIV.
switch to a sweep rate which displays about one cycle of
the waveform. Move the waveforms to the
graticule with the Y-P0S.I and
Turn the Variable Time Control until one cycle of the refer-
Each division represents 36” of the cycle.
l/II
pushbutton to the channel where the
kHz,
and CHOP. for
kHz.
Use probes which have equal
center
Y-POS.II
controls.
of the
Ml0 604
Subject to change without notice
Figure 2
Amplitude modulated oscillation: F = 1 MHz; f = 1 kHz;
m = 50 %
; UT =
28.3
mVrms.
Dual-Trace Phase Difference Measurements
T =
Horizontal distance
t
= Horizontal distance of zero-crossing points (cm).
foroneperiod(cm).
Assume a horizontal difference of 3 divisions (t = 3cm) and
a period of
10
divisions (T = 1 Ocm), the phase difference
91
can be calculated using the following formula:
=
108”
l.885rad
or
arcg,
-2~t =$ a2~~
=f
respectively.
Measurement of an amplitude modulation
The momentary amplitude u at time t of a HF-carrier voltage, which is amplitude modulated without distortion by a
sinusoidal AF voltage, is in accordance with the equation
u
=
U,.
sinQt
+
0,5m
. UT - cos(S&w)t -
where
= unmodulated carrier amplitude
U,
S2= 2~rF
0
=2nf
= angular carrier frequency
= modulation angular frequency
m= modulation factor (S 1 P 100
The lower side frequency F-fand the upper side frequency
F+f
arise because of the modulation apart from the carrier
frequency
F.
T
0,5m *
Figure 1
Amplitude and frequency spectrum for AM display (m = 50%)
UT
4
I
F-f F F+f
The display of the amplitude-modulated
evaluated with the oscilloscope provided the frequency
spectrum is inside the oscilloscope bandwidth. The time
base is set so that several cycles of the modulation frequency are visible. Strictly speaking, triggering should be external with modulation frequency (from the AF generator or a
demodulator). However, internal triggering is frequently possible with normal triggering using a suitable LEVEL setting
and possibly also using the time variable adjustment.
0,5m
- UT -
cos(l(r+o)t
%).
UT
0,5m
-
UT
4
HF
oscillation can be
Oscilloscope setting for a signal according to figure 2:
Depress no buttons.
TIM
E/DIV. :
0.2
Triggering: NORMAL with LEVEL-setting; internal (or
Y:
ms/div.
CH. I; 20mV/div; AC.
external) triggering.
If the two values
ulation factor is calculated from
a-
m =
a+b
aand
b
resp. m =
bare read from the screen, the mod-
a*.
100
[%J
where a = UT (l+m) and b = UT (l-m).
The variable controls for amplitude and time can be set arbitrarily in the modulation factor measurement. Their position does not influence the result.
Triggering and Timebase
With the LEVEL knob in locked position (turned ccw to AT
position = automatic triggering), a baseline is displayed con-
tinuously even when no signal is present. In this position it is
possible to obtain stable displays of virtually all uncomplicated, periodically repeating signals above 30 Hz. Adjustments of the
With normal triggering (LEVEL knob not in AT position) and
LEVEL adjustment, triggering of time/div. deflection can be
set in any point of a given signal. The triggering range which
can be set with the LEVEL control depends greatly on the
amplitude of the displayed signal. If it is less than 1 div, then
the range is quite small and performance of settings requires a delicate touch.
If the
LEVEL
ble.
In order to obtain a satisfactory stable display, the
must be triggered synchronously with the test signal. The
trigger signal can be derived from the test signal itself,
when internal triggering is selected, or from a frequency related signal applied to the external trigger input.
timebase
then are limited to
timebase
setting.
control is incorrectly set, no trace will be visi-
timebase
Subject to change without notice
Ml1 604
Loading...