Hameg HM407 User Manual

General information regarding the CE marking .......... 2
General Information ........................................................ 4
Use of tilt handle ............................................................ 4
Safety ............................................................................. 4
Intended purpose and operating conditions ................. 4
EMC ............................................................................... 5
Maintenance .................................................................. 5
Protective Switch-Off .................................................... 5
Power supply ................................................................. 5
Type of signal voltage ..................................................... 6
Amplitude Measurements ............................................. 6
Total value of input voltage ........................................... 7
Time Measurements ..................................................... 7
Connection of Test Signal ............................................. 8
Controls and readout....................................................... 9
Table of contents
Menu ................................................................................ 22
First Time Operation ..................................................... 23
Trace Rotation TR ........................................................ 23
Probe compensation and use ...................................... 23
Adjustment at 1kHz ..................................................... 23
Adjustment at 1MHz ................................................... 24
Operating modes of the vertical
amplifiers in Yt mode ................................................... 2 4
X-Y Operation ............................................................... 25
Phase comparison with Lissajous figures .................. 25
Phase difference measurement
in DUAL mode (Yt)....................................................... 25
Phase difference measurement in DUAL mode ........ 25
Measurement of an amplitude modulation ................ 26
Triggering and time base............................................. 26
Normal Triggering ........................................................ 27
(Slope) .................................................................... 27
Trigger coupling ........................................................... 2 7
Triggering of video signals........................................... 28
Line triggering (~) ........................................................ 28
Alternate triggering...................................................... 28
External triggering ........................................................ 28
Trigger indicator “TR” ................................................. 29
HOLD OFF-time adjustment ....................................... 29
(Only in analog mode).................................................. 29
Delay / After Delay Triggering ..................................... 29
(Only in analog mode).................................................. 29
Oscilloscope
E
Horizontal resolution.................................................... 3 4
Maximum signal frequency in storage mode ............. 34
Alias signal display ....................................................... 35
Operating modes of the vertical amplifiers ................ 35
Test Instructions ............................................................ 35
Genera l ......................................................................... 35
Cathode-Ray Tube: Brightness and Focus,
Linearity, Raster Distortion .......................................... 35
Astigmatism Check ...................................................... 35
Symmetry and Drift of the Vertical Amplifier ............. 35
Calibration of the Vertical Amplifier............................. 36
Transmission Performance .......................................... 36
of the Vertical Amplifier............................................... 36
Operating Modes:CH.I/II, DUAL, ADD, CHOP.,
INVERT and X-Y Operation.......................................... 36
Triggering Checks ........................................................ 36
Time base ..................................................................... 37
Hold Off time (analog mode only)............................... 37
Component Tester ....................................................... 37
Trace Alignment ........................................................... 3 7
HM 407
Auto Set ........................................................................... 3 1
Save/Recall ..................................................................... 31
Component Tester (analog mode)............................... 31
General......................................................................... 31
Using the Component Tester...................................... 32
Test Procedure ............................................................ 32
Test Pattern Displays ................................................... 32
Testing Resistors ......................................................... 32
Testing Capacitors and Inductors ................................ 32
Testing Semiconductors .............................................. 32
Testing Diodes ............................................................. 32
Testing Transistors ...................................................... 3 2
In-Circuit Tests ............................................................. 33
Storage Mode ................................................................. 33
Signal recording modes ............................................... 34
Vertical resolution ........................................................ 34
St.080598-Hüb/goRR
Subject to change without notice
Service Instructions ....................................................... 37
General ......................................................................... 37
Instrument Case Removal ........................................... 37
Caution ......................................................................... 38
Operating Voltages ...................................................... 38
Maximum and Minimum Brightness .......................... 38
Astigmatism control .................................................... 38
Trigger Threshold......................................................... 38
Trouble-Shooting the Instrument................................ 38
Adjustments ................................................................. 39
RS232 Interface - Remote Control ............................... 39
Safety ........................................................................... 39
Operation ..................................................................... 39
RS-232 Cable ............................................................... 39
RS-232 protocol ........................................................... 39
Baud-Rate Setting........................................................ 39
Data Communication ................................................... 39
Front Panel HM407......................................................... 40
1
KONFORMITÄTSERKLÄRUNG DECLARATION OF CONFORMITY DECLARATION DE CONFORMITE
Herstellers HAMEG GmbH Manufacturer Kelsterbacherstraße 15-19 Fabricant D - 60528 Frankfurt
Bezeichnung / Product name / Designation:
Oszilloskop/Oscilloscope/Oscilloscope
Typ / Type / Type: HM407
mit / with / avec: -
Optionen / Options / Options: HO79-6
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
General information regarding the CE marking
Instruments
Angewendete harmonisierte Normen / Harmonized standards applied / Normes harmonisées utilisées
Sicherheit / Safety / Sécurité
EN 61010-1: 1993 / IEC (CEI) 1010-1: 1990 A 1: 1992 / VDE 0411: 1994 Überspannungskategorie / Overvoltage category / Catégorie de surtension: II Verschmutzungsgrad / Degree of pollution / Degré de pollution: 2
Elektromagnetische Verträglichkeit / Electromagnetic compatibility Compatibilité électromagnétique
EN 50082-2: 1995 / VDE 0839 T82-2 ENV 50140: 1993 / IEC (CEI) 1004-4-3: 1995 / VDE 0847 T3 ENV 50141: 1993 / IEC (CEI) 1000-4-6 / VDE 0843 / 6 EN 61000-4-2: 1995 / IEC (CEI) 1000-4-2: 1995 / VDE 0847 T4-2 Prüfschärfe / Level / Niveau = 2
EN 61000-4-4: 1995 / IEC (CEI) 1000-4-4: 1995 / VDE 0847 T4-4: Prüfschärfe / Level / Niveau = 3
EN 50081-1: 1992 / EN 55011: 1991 / CISPR11: 1991 / VDE0875 T11: 1992 Gruppe / group / groupe = 1, Klasse / Class / Classe = B
Datum /Date /Date Unterschrift / Signature /Signatur
02.03.1998
Dr. J. Herzog
Technical Manager/Directeur Technique
®
HAMEG instruments fulfill 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 influence 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.) sufficiently 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 long. 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 long.
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. Influence on measuring instruments.
Under the presence of strong high frequency electric or magnetic fields, even with careful setup of the measuring equipment an influence of such signals is unavoidable. This will not cause damage or put the instrument out of operation. Small deviations of the measuring value (reading) exceeding the instruments specifications may result from such conditions in individual cases.
HAMEG GmbH
2
Subject to change without notice
Specifications
Vertical Deflection
Operating modes: Channel I or CH II separate,
Channel I and II: alternate or chopped (Chopper Frequency approx. 0.5MHz)
Sum or Difference from Channel I and ± Ch. II, XY-Mode: via CH I (X) and CH II (Y). Frequency range: 2x DC to 40MHz (3dB).
Risetime: <8.75ns. Overshoot: 1%. Deflection coefficient: 14 calibrated positions variable 2.5:1 to min. 50V/div.
1mV/div and 2mV/div: ±5% (0 to 10MHz (-3dB)) 5mV/div to 20V/div: ±3% (1-2-5sequence). Input impedance: 1M II 15pF.
Input coupling: DC - AC - GD (Ground) Input voltage: max. 400V (DC + peak AC).
Triggering
Automatic(peak to peak): Normal: DC-100MHz, LED for trigger indication. Slope: positive or negative. Sources: CH I or II, line, ext.
Coupling: AC (10Hz -100MHz), DC (0-100MHz), Triggering ext.: 0.3Vpp from DC to 100MHz
Active TV-Sync-Separator (field & line, pos, neg.) 2nd triggering (Del. Trig.): normal with level
Time coefficients: 1-2-5 sequence, Accuracy ±3% Analog: 22 cal. positions from 0.5s - 50ns/div. Digital:
Variable (analog) 2.5:1 up to 1.25s/div.
X-MAG. x10: analog to 10ns/div., dig. to 0.1µs/di v ±5% Delay: 120ms - 200ns, variable, Hold-off time (analog): variable to approx. 10:1. Bandwidth X-amplifier (analog): 0-3MHz (3dB).
Input X-amplifier via Channel II, Sensitivity see
X-Y-phase shift : <3° below 120kHz.
Operating modes: Refresh, Roll, Single, XY,
Envelope, Average (2 to 512 waveforms).
Automatic Dot Join function Sample Rate: max. 100MS/s (8 bit) Refresh rate: max. 180/s Record length: 2048 x 8 bit per channel.
Reference memoryReference memory
Reference memory: 2 x 2k x 8bit (EEPROM).
Reference memoryReference memory
Resolution: Y: 25 points/div, X: 200 points/div. Pre-/Posttrigger: 25, 50, 75, 100, -25,
Manual (front panel switches); Auto Set (automatic parameter selection). Save/Recall of 9 user-defined parameter settings RS232 interface for remote control via a PC. Remote control (Option) HZ68. Multifunction- Interface HO79-6(Option): RS232,
IEEE-488, Centronics (Postscript, HPGL, PCL, EPSON).
Readout: Display of parameter settings. Cursor measurement of V, t or 1/t
separate or in tracking mode.
Test voltage: approx. 7V Test current: max. 7mA Test frequency: approx.50Hz
One test lead is grounded (Safety Earth).
CRT: D14-364GY/123 or ER151-GH/-,rectangular screen (8x10cm) internal graticule
Acceleration voltage: approx 2000V Trace rotation: adjustable on front panel Calibrator: square-wave generator (tr <4ns) 1kHz/1MHz; Output: 0.2V ±1%. Analog Intensitymodulation, max. +5V (TTL). Line voltage: 100-240V AC ±10%, 50/60Hz Power consumption: approx. 42 Watt at 50Hz.
Min./Max. ambient temperature: 0°C...+40°C Protective system: Safety class I (IEC1010-1) Weight: approx. 5.6kg, color: techno-brown Cabinet: W 285, H 125, D 380 mm 3/98
CH I alternate CH II (≤ 0.8div.)
HF (50kHz - 100MHz), LF (0 - 1.5kHz).
control DC to 100 MHz.
Horizontal Deflection
25 cal. positions from 100s - 1µs/div.
Digital Storage
Operation / Control
Component Tester
General Information
≤≤
20Hz-100MHz (≤0.5div),
≤≤
Channel II.
-50, -75%.
(frequency),
(open circuit).
rms
(short circuit).
rms
40MHz Analog-/Digital-Scope HM407
Auto-Set, Save/Recall, Readout/Cursor, RS232 Interface Analog: 2 x DC-40MHz, max. 1mV/div, Timebase 0.5s/div - 10ns/div
Triggering DC - 100MHz, Component Tester, 1MHz Calibrator
Digital: Max. Sampling Rate 100MS/s, Timebase 100s/div - 0.1µs/div
Storage 2 x 2048 x 8 bit, Reference Memory, Post/Pre-Trigger
.
The worldwide success of HAMEG´s HM205 and HM305 has led to the introduction of the new microprocessor controlled HM407 Analog/Digital oscilloscope. This instrument offers much more performance and specifications over its predecessores. The HM407 incorporates a microprocessor-based system that extensively automates operation. The majority of signals can be displayed by simply pressing the “Autoset“ button. A “Save/Recall“ function is available for storing frequently used setup parameters.
The increased maximum sampling rate of 100MS/s now allows to capture a
10MHz signal in “Single“ mode with 10 samples (dots) per period. The automatic Dot-Join function provides linear connections between the captured points,
ensuring that all digitized signals are displayed without gaps. New features are the two reference memories, allowing their contents to be compared with the live signal at any time. Cursors can be activated for waveform measurements. All important parameter settings are displayed on the CRT screen. The built-in RS232- Interface enables remote control operation and signal processing via a PC.
Unique in its price range is also the analog section of the HM407. The increased bandwidth of 40MHz (-3dB) allows the stable display of signals up to 100MHz. As always, the Component Tester with one-button control is a standard feature in the HM407. This is also true for the switchable 1kHz/1MHz Calibrator which permits you to check the transient characteristics from probe tip to the screen at any time.
All in all, the new HM407 presents itself as a practical hands-on oscilloscope for today’s progressive measurement requirements offering a price/performance ra­tio that sets new standards world-wide.
Screen photo of stored sinewave signals. Screen shot of measurement software.
Storage Modes: Refresh, Single, Roll, Average and Envelope
Accessories supplied: Line Cord, Operators Manual, 2 Probes1:1/ 10:1
Subject to change without notice
3
General Information
General Information
This oscilloscope is easy to operate. The logical arrangement of the controls allows anyone to quickly become familiar with the operation of the instrument, 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.
Symbols
ATTENTION - refer to manual Danger - High voltage Protective ground (earth) terminal
Use of tilt handle
To view the screen from the best angle, there are three different positions (C, D, E) for setting up the instrument. If the instrument is set down on the floor after being carried, the handle automatically remains in the upright carrying position (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 (10° inclination), the handle should be turned to the opposite direction of the carrying 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 carrying by turning it to the upper side to lock in the B position. At the same time, the instrument must be lifted, because otherwise the handle will jump back.
The case, chassis and all measuring terminals are connected to the protective earth contact of the appliance inlet. The instrument operates according to Safety Class I (three­conductor 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.
The mains/line plug must be inserted before connections are made to measuring circuits.
The grounded accessible metal parts (case, sockets, jacks) and the mains/line supply contacts (line/live, neutral) of the instrument have been tested against insulation breakdown with 2200V DC.
Under certain conditions, 50Hz 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 device being investigated.
Most cathode-ray tubes develop X-rays. However, the dose equivalent rate falls far below the maximum permissible value of 36pA/kg (0.5mR/h).
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 likely to be impa­ired if, for example, the instrument
• shows visible damage,
• fails to perform the intended measurements,
• has been subjected to prolonged storage under unfavorable conditions (e.g. in the open or in moist environments),
• has been subject to severe transport stress (e.g. in poor packaging).
Safety
This instrument has been designed and tested in accordance with IEC Publication 1010-1 (overvoltage category II, pollution degree 2), Safety requirements for electrical equipment for measurement, control, and laboratory use. The CENELEC regulations EN 61010-1 correspond to this standard. It has left the factory in a safe condition. This 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 a safe condition.
Intended purpose and operating conditions
This instrument must be used only by qualified experts who are aware of the risks of electrical measurement.
The instrument is specified for operation in industry, light industry, commercial and residential environments.
Due to safety reasons the instrument must only be connected to a properly installed power outlet, containing a protective earth conductor. The protective earth connection must not be broken. The power plug must be inserted in the power outlet while any connection is made to the test device.
The instrument has been designed for indoor use. The permissible ambient temperature range during operation is +10°C (+50°F) ... +40°C (+104°F). It may occasionally be subjected to temperatures between +10°C (+50°F) and -10°C (+14°F) without degrading its safety. The permissible ambient temperature range for storage or transportation is -40°C (­40°F) ... +70°C (+158°F). 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
4
Subject to change without notice
General Information
explosive, corrosive, dusty, or moist environments. The oscilloscope can be operated in any position, but the convection cooling must not be impaired. The ventilation 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 30minutes at an ambient temperature between +15°C (+59°F) and +30°C (+86°F). Values without tolerances are typical for an average instrument.
EMC
This instrument conforms to the European standards regarding the electromagnetic compatibility. The applied standards are: Generic immunity standard EN50082-2:1995 (for industrial environment) Generic emission standard EN50081-1:1992 (for residential, commercial and light industry environment).
This means that the instrument has been tested to the highest standards.
Please note that under the influence of strong electromagnetic fields, such signals may be superimposed on the measured signals.
Under certain conditions this is unavoidable due to the instrument’s high input sensitivity, high input impedance and bandwidth. Shielded measuring cables, shielding and earthing of the device under test may reduce or eliminate those effects.
Warranty
HAMEG warrants to its Customers that the products it manufactures and sells will be free from defects in materials and workmanship for a period of 2 years. This warranty shall not apply to any defect, failure or damage caused by improper use or inadequate maintenance and care. HAMEG shall not be obliged to provide service under this warranty to repair damage resulting from attempts by personnel other than HAMEG representatives to install, repair, service or modify these products.
In order to obtain service under this warranty, Customers must contact and notify the distributor who has sold the product. Each instrument is subjected to a quality test with 10 hour burn-in before leaving the production. Practically all early failures are detected by this method. In the case of shipments by post, rail or carrier it is recommended 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.
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 +1% 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.
Protective Switch-Off
This instrument is equipped with a switch mode power supply. It has both overvoltage and overload protection, which will cause the switch mode supply to limit power consumption to a minimum. In this case a ticking noise may be heard.
Power supply
The oscilloscope operates on mains/line voltages between 100VAC and 240VAC. No means of switching to different input voltages has therefore been provided.
The power input fuses are externally accessible. The fuseholder is located above the 3-pole power connector. The power input fuses are externally accessible, if the rubber connector is removed. The fuseholder can be released by pressing its plastic retainers with the aid of a small screwdriver. The retainers are located on the right and left side of the holder and must be pressed towards the center. The fuse(s) can then be replaced and pressed in until locked on both sides.
Use of patched fuses or short-circuiting of the fuseholder is not permissible; HAMEG assumes no liability whatsoever for any damage caused as a result, and all warranty claims become null and void.
Fuse type: Size 5x20mm; 0.8A, 250V AC fuse; must meet IEC specification 127, Sheet III (or DIN 41 662 or DIN 41 571, sheet 3). Time characteristic: time-lag (T).
Attention! There is a fuse located inside the instrument within the switch mode power supply:
Size 5x20mm; 0.8A, 250V AC fuse; must meet IEC specification 127, Sheet III (or DIN 41 662 or DIN 41 571, sheet 3). Time characteristic: fast (F).
This fuse must not be replaced by the operator!
Maintenance
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 HAMEG scope tester HZ 60, which despite its low price is highly suitable for tasks of this type, is very much
Subject to change without notice
5
Type of signal voltage
Type of signal voltage
The oscilloscope HM407 allows examination of DC voltages and most repetitive signals in the frequency range up to at least 40MHz (-3dB).
The vertical amplifiers have been designed for minimum overshoot and therefore permit a true signal display.
The display of sinusoidal signals within the bandwidth limits causes no problems, but an increasing error in measurement due to gain reduction must be taken into account when measuring high frequency signals. This error becomes noticeable at approx. 14MHz. At approx. 18MHz the reduction is approx. 10% and the real voltage value is 11% higher. The gain reduction error can not be defined exactly as the -3dB bandwidth of the amplifiers differ between 40MHz and 42MHz. For sinewave signals the -6dB limit is approx. 50MHz.
When examining square or pulse type waveforms, attention must be paid to the harmonic content of such signals. The repetition frequency (fundamental frequency) of the signal must therefore be significantly smaller than the upper limit frequency of the vertical amplifier.
Displaying composite signals can be difficult, especially if they contain no repetitive higher amplitude content which can be used for triggering. This is the case with bursts, for instance. To obtain a well-triggered display in this case, the assistance of the variable holdoff function or the delayed time base may be required. Television video signals are relatively easy to trigger using the built-in TV-Sync-Separator (TV).
The relationship between the different voltage magnitudes can be seen from the following figure.
Voltage values of a sine curve Vrms = effective value; Vp = simple peak or crest value; Vpp = peak-to-peak value; Vmom = momentary value.
The minimum signal voltage which must be applied to the Y input for a trace of 1div height is 1mVpp (± 5%) when this deflection coefficient is displayed on the screen (readout) and the vernier is switched off (VAR-LED dark). However, smaller signals than this may also be displayed. The deflection coefficients are indicated in mV/div or V/div (peak-to-peak value).
The magnitude of the applied voltage is ascertained by multiplying the selected deflection coefficient by the vertical display height in div. If an attenuator probe x10 is used, a further multiplication by a factor of 10 is required to ascertain the correct voltage value.
For optional operation as a DC or AC voltage amplifier, each vertical amplifier input is provided with a DC/AC switch. DC coupling should only be used with a series-connected attenuator probe or at very low frequencies or if the measurement of the DC voltage content of the signal is absolutely necessary.
When displaying very low frequency pulses, the flat tops may be sloping with AC coupling of the vertical amplifier (AC limit frequency approx. 1.6 Hz for 3dB). In this case, DC operation is preferred, provided the signal voltage is not superimposed on a too high DC level. Otherwise a capacitor of adequate capacitance must be connected to the input of the vertical amplifier with DC coupling. This capacitor must have a sufficiently high breakdown voltage rating. DC coupling is also recommended for the display of logic and pulse signals, especially if the pulse duty factor changes constantly. Otherwise the display will move upwards or downwards at each change. Pure direct voltages can only be measured with DC-coupling.
The input coupling is selectable by the AC/DC pushbutton. The actual setting is displayed in the readout with the ” = ” symbol for DC- and the
~symbol for AC coupling.
Amplitude Measurements
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-peak voltage (Vpp) value is applied. The latter corresponds to the real potential difference between the most positive and most negative points of a signal waveform.
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 2x2 = 2.83. Conversely, it should be observed that sinusoidal voltages indicated in Vrms (Veff) have 2.83 times the potential difference in Vpp.
For exact amplitude measurements, the variable control (VAR) must be set to its calibrated detent CAL position.
With the variable control activated the deflection sensitivity can be reduced up to a ratio of 2.5 to 1 (please note “controls and readout”). Therefore any intermediate value is possible within the 1-2-5 sequence of the attenuator(s).
With direct connection to the vertical input, signals up to 400Vpp may be displayed (attenuator set to 20V/div, variable control to 2.5:1).
With the designations
H= display height in div, U= signal voltage in Vpp at the vertical input, D= deflection coefficient in V/div at attenuator switch,
the required value can be calculated from the two given quantities:
However, these three values are not freely selectable. They have to be within the following limits (trigger threshold, accuracy of reading):
H between 0.5 and 8div, if possible 3.2 to 8div, U between 1mVpp and 160Vpp, D between 1mV/div and 20V/div in 1-2-5 sequence.
Examples: Set deflection coefficient D = 50mV/div 0.05V/div, observed display height H = 4.6div, required voltage U = 0.05x4.6 = 0.23Vpp. Input voltage U = 5Vpp, set deflection coefficient D = 1V/div, required display height H = 5:1 = 5div.
6
Subject to change without notice
Type of signal voltage
Signal voltage U = 230Vrmsx2√2 = 651Vpp (voltage > 160Vpp, with probe 10:1: U = 65.1Vpp), desired display height H = min. 3.2div, max. 8div, max. deflection coefficient D = 65.1:3.2 = 20.3V/div, min. deflection coefficient D = 65.1:8 = 8.1V/div, adjusted deflection coefficient D = 10V/div.
The previous examples are related to the CRT graticule reading. The results can also be determined with the aid of the DV cursor measurement (please note “controls and readout”). The input voltage must not exceed 400V, independent from the polarity.
If an AC voltage which is superimposed on a DC voltage is applied, the maximum peak value of both voltages must not exceed + or - 400V. So for AC voltages with a mean value of zero volt the maximum peak to peak value is 800Vpp.
If attenuator probes with higher limits are used, the probes limits are valid only if the oscilloscope is set to DC input coupling.
If DC voltages are applied under AC input coupling conditions the oscilloscope maximum input voltage value remains 400V. The attenuator consists of a resistor in the probe and the 1M input resistor of the oscilloscope, which are disabled by the AC input coupling capacity when AC coupling is selected. This also applies to DC voltages with superimposed AC voltages. It also must be noted that due to the capacitive resistance of the AC input coupling capacitor, the attenuation ratio depends on the signal frequency. For sinewave signals with frequencies higher than 40Hz this influence is negligible.
peak and the DC voltage results in the max. voltage (DC + ACpeak).
Time Measurements
As a rule, most signals to be displayed are periodically repeating processes, also called periods. The number of periods per second is the repetition frequency. Depending on the time base setting (TIME/DIV.-knob) indicated by the readout, one or several signal periods or only a part of a period can be displayed. The time coefficients are stated in ms/div, µs/div or ns/div. The following examples are related to the CRT graticule reading. The results can also be determined with the aid of the T and 1/T cursor measurement (please note “ controls and readout”).
The duration of a signal period or a part of it is determined by multiplying the relevant time (horizontal distance in div) by the (calibrated) time coefficient displayed in the readout. Uncalibrated, the time base speed can be reduced until a maximum factor of 2.5 is reached. Therefore any intermediate value is possible within the 1-2-5 sequence.
With the designations L = displayed wave length in div of one period,
T = time in seconds for one period, F = recurrence frequency in Hz of the signal, Tc= time coefficient in ms, µs or ns/div and the relation F = 1/T, the following equations can be stated:
With the above listed exceptions HAMEG 10:1 probes can be used for DC measurements up to 600V or AC voltages (with a mean value of zero volt) of 1200Vpp. The 100:1 probe HZ53 allows for 1200V DC or 2400Vpp for AC.
It should be noted that its AC peak value is derated at higher frequencies. If a normal x10 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 oscilloscope, a normal x10 probe is sufficient. In this case, an appropriate high voltage capacitor (approx. 22­68nF) must be connected in series with the input tip of the probe.
With Y-POS. control (input coupling to GD) it is possible to use a horizontal graticule line as reference line for ground potential before the measurement. It can lie below or above the horizon­tal central line according to whether positive and/or negative deviations from the ground potential are to be measured.
Total value of input voltage
However, these four values are not freely selectable. They have to be within the following limits:
L between 0.2 and 10div, if possible 4 to 10div, T between 10ns and 5s, F between 0.5Hz and 100MHz, Tc between 100ns/div and 500ms/div in 1-2-5 sequence
(with X-MAG. (x10) inactive), and
Tc between 10ns/div and 50ms/div in 1-2-5 sequence
(with X-MAG. (x10) active).
Examples: Displayed wavelength L = 7div, set time coefficient Tc = 100ns/div, required period T = 7x100x10 required rec. freq. F = 1:(0.7x10
-9
= 0.7µs
-6
) = 1.428MHz.
Signal period T = 1s, set time coefficient Tc = 0.2s/div, required wavelength L = 1:0.2 = 5div.
Displayed ripple wavelength L = 1div, set time coefficient Tc = 10ms/div, required ripple freq. F = 1:(1x10x10
-3
) = 100Hz.
TV-line frequency F = 15625Hz, set time coefficient Tc = 10µs/div, required wavelength L = 1:(15 625x10-5) = 6.4div.
The dotted line shows a voltage alternating at zero volt level. If superimposed on a DC voltage, the addition of the positive
Subject to change without notice
Sine wavelength L = min. 4div, max. 10div, Frequency F = 1kHz, max. time coefficient Tc = 1:(4x10
3
) = 0.25ms/div, min. time coefficient Tc = 1:(10x103) = 0.1ms/div, set time coefficient Tc = 0.2ms/div, required wavelength L = 1:(10
3
x0.2x10-3) = 5div.
7
Type of signal voltage
Displayed wavelength L = 0.8div, set time coefficient Tc = 0.5µs/div, pressed X-MAG. (x10) button: Tc = 0.05µs/div, required rec. freq. F = 1:(0.8x0.05x10 required period T = 1:(25x10
6
) = 40ns.
-6
) = 25MHz,
If the time is relatively short as compared with the complete signal period, an expanded time scale should always be applied (X-MAG. (x10) active). In this case, the time interval of interest can be shifted to the screen center using the X-POS. control.
When investigating pulse or square waveforms, the critical feature is the risetime of the voltage step. To ensure that transients, ramp-offs, and bandwidth limits do not unduly influence the measuring accuracy, the risetime is generally measured between 10% and 90% of the vertical pulse height. For measurement, adjust the Y deflection coefficient using its variable function (uncalibrated) together with the Y-POS. control so that the pulse height is precisely aligned with the 0% and 100% lines of the internal graticule. The 10% and 90% points of the signal will now coincide with the 10% and 90% graticule lines. The risetime is given by the product of the horizontal distance in div between these two coincident points and the calibrated time coefficient setting. The fall time of a pulse can also be measured by using this method.
The following figure shows correct positioning of the oscilloscope trace for accurate risetime measurement.
measure in any display position and at any signal amplitude. It is only important that the full height of the signal edge of interest is visible in its full length at not too great steepness and that the horizontal distance at 10% and 90% of the amplitude is measured. If the edge shows rounding or overshooting, the 100% should not be related to the peak values but to the mean pulse heights. Breaks or peaks (glitches) next to the edge are also not taken into account. With very severe transient distortions, the rise and fall time measurement has little meaning. For amplifiers with approximately constant group delay (therefore good pulse transmission performance) the following numerical relationship between rise time tr (in ns) and bandwidth B (in MHz) applies:
Connection of Test Signal
In most cases briefly depressing the AUTO SET causes a useful signal related instrument setting. The following explanations refer to special applications and/or signals, demanding a manual instrument setting. The description of the controls is explained in the section “controls and readout”.
Caution: When connecting unknown signals to the oscilloscope input, always use a x10 probe, automatic triggering and set the input coupling switch to DC (readout). The attenuator should initially be set to 20V/div.
With a time coefficient of 10ns/div (X x10 magnification active), the example shown in the above figure results in a total measured risetime of
= 1.6div x 10ns/div = 16ns
t
tot
When very fast risetimes are being measured, the risetimes of the oscilloscope amplifier and of the attenuator probe has to be deducted from the measured time value. The risetime of the signal can be calculated using the following formula.
In this t the oscilloscope amplifier (approx. 8.75ns), and t of the probe (e.g. = 2ns). If t can be taken as the risetime of the pulse, and calculation is
is the total measured risetime, t
tot
is greater than 100ns, then t
tot
is the risetime of
osc
the risetime
p
unnecessary. Calculation of the example in the figure above results in a signal
risetime
= 162 - 8.752 - 22 = 13.25ns
t
r
The measurement of the rise or fall time is not limited to the trace dimensions shown in the above diagram. It is only particularly simple in this way. In principle it is possible to
Sometimes the trace will disappear after an input signal has been applied. Then a higher deflection coefficient (lower input sensitivity) must be chosen until the vertical signal height is only 3-8div. With a signal amplitude greater than 160Vpp and the deflection coefficient (VOLTS/DIV.) in calibrated condition, an attenuator probe must be inserted before the vertical input. If, after applying the signal, the trace is nearly blanked, the period of the signal is probably substantially longer than the set time deflection coefficient (TIME/DIV.). It should be switched to an adequately larger time coefficient.
The signal to be displayed can be connected directly to the Y­input of the oscilloscope with a shielded test cable such as HZ32 or HZ34, or reduced through a x10 or x100 attenuator probe. The use of test cables with high impedance circuits is only recommended for relatively low frequencies (up to approx. 50kHz). For higher frequencies, the signal source must be of low impedance, i.e. matched to the characteristic resistance of the cable (as a rule 50). Especially when transmitting square and pulse signals, a resistor equal to the characteristic impedance of the cable must also be connected across the cable directly at the Y-input of the oscilloscope. When using a 50 cable such as the HZ34, a 50 through termination type HZ22 is available from HAMEG. When transmitting square signals with short rise times, transient phenomena on the edges and top of the signal may become visible if the correct termination is not used. A terminating resistance is sometimes recommended with sine signals as well. Certain amplifiers, generators or their attenuators maintain the nominal output
tot
voltage independent of frequency only if their connection cable is terminated with the prescribed resistance. Here it must be noted that the terminating resistor HZ22 will only dissipate a maximum of 2Watts. This power is reached with 10Vrms or at 28.3Vpp with sine signal. If a x10 or x100 attenuator probe is used, no termination is necessary. In this case, the connecting cable is matched directly to the high impedance input of the oscilloscope. When using attenuators probes, even high internal impedance sources are only slightly loaded (approx. 10M II 12pF or 100M II 5pF with HZ53). Therefore, if the voltage loss due to the attenuation of the
8
Subject to change without notice
Controls and readout
probe can be compensated by a higher amplitude setting, the probe should always be used. The series impedance of the probe provides a certain amount of protection for the input of the vertical amplifier. Because of their separate manufacture, all attenuator probes are only partially compensated, therefore accurate compensation must be performed on the oscilloscope (see Probe compensation ).
Standard attenuator probes on the oscilloscope normally reduce its bandwidth and increase the rise time. In all cases where the oscilloscope bandwidth must be fully utilized (e.g. for pulses with steep edges) we strongly advise using the probes HZ51 (x10) HZ52 (x10 HF) and HZ54 (x1 and x10). This can save the purchase of an oscilloscope with larger bandwidth.
The probes mentioned have a HF-calibration in addition to low frequency calibration adjustment. Thus a group delay correction to the upper limit frequency of the oscilloscope is possible with the aid of an 1MHz calibrator, e.g. HZ60.
In fact the bandwidth and rise time of the oscilloscope are not noticeably changed with these probe types and the waveform reproduction fidelity can even be improved because the probe can be matched to the oscilloscopes individual pulse response.
If a x10 or x100 attenuator probe is used, DC input coupling must always be used at voltages above 400V. With AC coupling of low frequency signals, the attenuation is no longer independent of frequency, pulses can show pulse tilts. Direct voltages are suppressed but load the oscilloscope input coupling capacitor concerned. Its voltage rating is max. 400 V (DC + peak AC). DC input coupling is therefore of quite special importance with a x100 attenuation probe which usually has a voltage rating of max. 1200 V (DC + peak AC). A capacitor of corresponding capacitance and voltage rating may be connected in series with the attenuator probe input for blocking DC voltage (e.g. for hum voltage measurement).
With all attenuator probes, the maximum AC input voltage must be derated with frequency usually above 20kHz. Therefore the derating curve of the attenuator probe type concerned must be taken into account. The selection of the ground point on the test object is important when displaying small signal voltages. It should always be as close as possible to the measuring point. If this is not done, serious signal distortion may result from spurious currents through the ground leads or chassis parts. The ground leads on attenuator probes are also particularly critical. They should be as short and thick as possible. When the attenuator probe is connected to a BNC­socket, a BNC-adapter, should be used. In this way ground and matching problems are eliminated. Hum or interference appearing in the measuring circuit (especially when a small deflection coefficient is used) is possibly caused by multiple grounding because equalizing currents can flow in the shielding of the test cables (voltage drop between the protective conductor connections, caused by external equipment connected to the mains/line, e.g. signal generators with interference protection capacitors).
Controls and readout
The following description assumes that the operating mode “COMPONENT TEST” is switched off.
parameter settings are displayed in the screen readout when the oscilloscope is on.
The LED indicators on the large front panel facilitate operation and provide additional information. Electrical end positions of controls are indicated by acoustic signal (beep).
All important measuring
All controls, except the power switch (POWER), the calibration frequency pushbutton (CAL. 1kHz/1MHz), the FOCUS control and the trace rotation control, are electronically set and interrogated. Thus, all electronically set functions and their current settings can be stored and also remotely controlled. Some controls are only operative in the digital mode or have a different function. Explanations pertaining to them are indicated with the hint “storage mode only”.
The large front panel is, as is usual with Hameg oscilloscopes, is marked with several fields.
The following controls and LED indicators are located on the top, to the right of the screen, above the horizontal line:
(1) POWER - Pushbutton and symbols for ON (I) and OFF (O).
After the oscilloscope is switched on, all LEDs are lit and an automated instrument test is performed. During this time the HAMEG logo and the software version are displayed on the screen. After the internal test is completed successfully, the overlay is switched off and the normal operation mode is present. Then the last used settings become activated and one LED indicates the ON condition.
It is possible to modify certain functions (SETUP) or to call automatic calibration procedures (CALIBRATE).
relating to this see section “MENU”
(2) AUTOSET - Pushbutton
Briefly depressing this pushbutton results in an automatic instrument setting automatically selecting Yt mode. The instrument is set to the last used Yt mode setting (CH I,
CH II or DUAL). SEARCH (SEA) and DELAY (DEL and DTR) mode is
automatically switched off.
Please note “AUTO SET”
.
For details
.
STORAGE MODE ONLY
Additionally, AUTOSET automatically selects refresh mode (RFR) when SINGLE (SGL) or ROLL (ROL) function is in operation.
(3) RM - LED
The remote control mode can be switched on or off (”RM” LED dark) via the RS232 interface. On condition that the “RM” LED is lit, all electronically selectable controls on front panel are inactive. This state can be left by depressing the AUTOSET pushbutton provided it was not deactivated via the interface.
STORAGE MODE ONLY
The RM-LED is lit during data transfer via the built in RS232 interface. At this time the controls are inactive.
(4) INTENS - READOUT - Control knob with associated
pushbutton and LEDs. This control knob is for adjusting the trace (A) and readout
intensity (RO). Turning this knob clockwise increases and turning it counterclockwise decreases the intensity.
The READOUT pushbutton below is for selecting the function in two ways.
Subject to change without notice
9
Controls and readout
If the readout (RO) is not switched off, briefly pressing the READOUT pushbutton switches over the INTENS knob function indicated by a LED in the sequence:
Yt (time base) mode: A - RO - A XY mode: A - RO - A. Component Test: A - RO - A.
Pressing and holding the READOUT pushbutton switches the readout on or off. In readout off condition the INTENS knob function can consequently not be set to RO.
Switching the readout off, may be required if interference is visible on the signal(s). Such interference may also originate from the chopper generator if the instrument is operated in chopped DUAL mode.
With the exception of the letters “CT” all other READOUT information is switched off in COMPONENT TEST mode.
All INTENS settings are stored after the instrument is switched off.
The AUTOSET function switches the readout on. The INTENS setting for each function is automatically set to the mean value, if less intensity was previously selected.
Attention! The time base ranges are dependent on the operating mode Analog or Digital (storage). The following data relate to operation without X magnification (X-MAG. x10).
Analog mode:
Time base from 500ms/cm to 50ns/cm (without trace delay).
With trace delay, from 20ms/cm to 50ns/cm. Delay ranges from 20ms/cm to 100ns/cm.
Digital mode:
Time bases from 100s/cm to 1µs/cm. This results in the following behavior when switched
from analog to digital mode and vice versa:
1. If in analog mode, the time base has been selected between 500ns/cm and 50ns/cm, then on switching to digital mode the lowest available time coefficient will be automatically selected, i.e. 1µs/cm. If now one switches back to analog mode without having made any time base changes in the digital mode, then the last time base selected in the analog mode is again active (e.g. 500ns/cm).
If on the other hand, the time base is changed after switching over to digital mode (e.g. to 2µs/cm). Then, when switched back to analog mode, the time base in analog mode will be set to the value selected in the digital mode (e.g. 2µs/cm).
(5) T R - Trimming potentiometer.
The trace rotation control can be adjusted with a small screwdriver (
(6) FOCUS - Control knob.
This control knob effects both the trace and the readout sharpness.
(7) STOR. ON / HOLD - Pushbutton with two functions.
STOR. ON
Pressing and holding the button switches from analog (Yt or XY) to storage mode and vice versa. If CT (Component Tester) mode is present (only available in analog mode), it must be switched off first to enable switching over to storage mode.
The oscilloscope is in analog mode if none of the LED’s associated with the STOR.MODE (9) pushbuttons are lit and a pre- or post-trigger value (PT...%) is not indicated by the readout. Pressing and holding the STOR. ON button switches over to the digital mode, but without changing the channel operating mode (CH I, CH II, DUAL, ADD and XY). The actual signal capture mode is indicated by one of the STOR. MODE-LED‘s (RFR - ENV - AVM - ROL) and in addition displayed by the readout. In digital XY mode the RFR-LED is lit and the readout indicates XY.
If digital SINGLE event (SGL) capture mode is selected, all STOR. MODE-LED‘s are dark, but the readout displays the pre- or post-trigger value (PT...%).
please note “trace rotation TR”
)
2.If a time base between 100s/cm and 1s/cm has been set in the digital mode and the mode is switched to analog, then the time base in analog mode is automatically set to 500ms/cm. The rest is as described before.
The X-MAG x10 setting remains unchanged when switched from analog to digital mode and vice versa.
STORAGE MODE ONLY
If by pressing and holding the STOR. ON / HOLD button, the mode is switched to digital, then one of the associated LED’s lights up. Which one it is, depends on the last selected digital operation.
Exception Switching over from analog SINGLE mode to digital mode sets the instrument automatically to digital SINGLE mode.
Attention The possibilities of delayed trace and the related operations with delayed time base are not available in digital mode.
For additional information regarding the digital mode, see section STORAGE OPERATION.
HOLD
STORAGE MODE ONLY
Briefly pressing the STOR. ON / HOLD pushbutton switches over between protected and unprotected mode of the current memory contents.
The current contents of the memory are protected against overwriting when HLD (HOLD) instead of channel
10
Subject to change without notice
Controls and readout
information (e.g. Y1... ) is displayed in the readout. This prevents a change in the Yt mode setting, but it is possible to select between DUAL (Yt) and XY display by pressing the DUAL (22) pushbutton if one of these modes was selected before activating HOLD.
If HOLD is switched off, one can observe how the existing memory contents are successively overwritten by new data especially with slow time base settings and refresh mode. Protecting the memory contents in the middle of a data acquisition process can result in an irregularity at the junction of old (right) and new data (left). This can be avoided by recording in single shot mode (SGL), even though the input signal is repetitive. At the end of a sweep, one can use HOLD to protect the contents against being overwritten by an unintentional actuation of RESET (RES).
The signal in each of the current memory can be shifted in the vertical direction (+/- 4cm) with the corresponding Y-POS rotary knob when HOLD is operative.
The original trace position will be lost when shifted vertically, but this can be found again. To this end the Y- POS knob in question must be rotated quickly. Once the original position is reached, the trace does not shift anymore although the knob is rotated further. Simultaneously a signal tone sounds. To shift the trace vertically again it will be required to stop rotating the knob for at least about 2 seconds.
Attention! The dynamic range limits of the A/D converter may become visible if a Y-position shift is performed after storage. This can affect those signal parts which were originally above or below the screen.
PRETRIGGER 0% PRETRIGGER (readout “PT0%”) means that the
signal display starts with the trigger event. The trigger point symbol indicates this position. If the X-POS. control is not in center position, an arrow pointing to the left may be displayed. Then the X-POS. control must be turned clockwise until the arrow is no longer visible.
25% PRETRIGGER (readout “PT25%”) is achieved after pressing the PTR button once. The signal display starts with 25% pre-history and the trigger point symbol is shifted 2.5 divisions to the right.
Each time the PTR button is pressed the PRETRIGGER value increases by 25% until 100% is reached. If in 100% condition an arrow symbol is displayed in addition to the trigger point symbol, the X-POS. control should be turned ccw. to make the trigger point visible on the screen.
The duration of the prehistory is determined by multiplying the time coefficient by the pretrigger value (in divisions). E.g. 20ms/div x 7,5 div (= 75% pretrigger) = 150ms.
POSTTRIGGER
In POSTTRIGGER condition the trigger point is always to the left of the screen and therefore not visible. The trigger point symbol then only indicates the LEVEL setting. An additional arrow symbol which points to the left is displayed to indicate post trigger operation. In POSTTRIGGER condition the arrow symbol does not indicate a wrong X­POS. setting. A minus sign (-) placed in front of the percentage value, is displayed by the readout for POSTTRIGGER mode indication.
Proceeding from 100% pre-trigger, the instrument swit­ches over to 75% POSTTRIGGER (“PT-75%”) after the PTR button is pressed. Then the trigger point is 7.5 div to the left of the trace start on the screen. This means that the signal capture starts 7.5 x time deflection coefficient after the trigger event occurred.
(8) PTR - Pushbutton for PRE and POST Trigger selection.
This function is not available in analog mode.
The PRETRIGGER function is used to capture signals that occur prior to a trigger event, making the pre-history visible. In contrast to this function, the POSTTRIGGER is used to capture signals occurring after the trigger event, which could not be captured in 0% Pretrigger condition. Due to the dependence on trigger events, neither function is available in the trigger independent modes XY and ROLL.
The actual PRE or POSTTRIGGER value is displayed by the readout and changes, each time the PTR button is pressed, in the following sequence: PT0%, PT25%,
PT50%, PT75%, PT100%, PT-75%, PT-50%, PT-25%
and back to PT0%. The values refer to the X-axis (graticule) of the screen display (10% = 1div).
The following description assumes that the X magnifier (x10) is inactive and the signal display starts on the leftmost vertical graticule line. It is also assumed that a trigger mode (source, coupling) is chosen, in which the trigger point symbol is displayed. In contrast to analog mode, using pre-trigger the trigger point symbol can be shifted in X-direction.
Every time the PTR button is pressed the POSTTRIGGER value changes in 25% steps until PTR-25% is active. When the PTR button is pressed again, both post and pre­trigger are switched off and the readout indicates “PT0%”.
Attention! In time base settings from 100s/div to 50ms/div the pre­or post-trigger is automatically switched off (“PT0%) if refresh (RFR), envelope (ENV) or average (AVM) mode is active. This is to avoid excessive waiting times.
If the pre- or post-trigger function is required in combination with those time coefficients, SINGLE (SGL) mode opera­tion must be used.
(9) STOR. MODE - Pushbuttons with associated LEDs.
These functions are not available in analog mode.
If digital SINGLE (SGL) mode has not been chosen, one of the associated LEDs is lit. The signal capture and display mode can be selected by pressing one of the buttons. The mode setting is indicated by one of the LEDs (RFR, ENV, AVM and ROL) and also displayed by the readout. The only exception is in XY storage mode. Then the RFR-LED is lit and the readout displays XY. No other signal capture and display mode can be chosen in XY mode.
Subject to change without notice
11
Controls and readout
The desired Yt signal capture mode can be selected by pressing the upper or lower STOR. MODE button.
The following description presumes that HOLD (HLD) is not activated and the trigger conditions are met.
(9 ) RFR - stands for refresh operation. In this mode, as in
analog mode, periodically repeating signals can be captured and displayed.
The signal acquisition is started by triggering the digital time base. Then the previously captured and displayed signal will be overwritten with the current signal. This will be displayed until the digital time base is triggered again. This is in contrast to analog operation where the screen remains blank when the time base is not triggered.
In refresh mode, the signal acquisition can be effected with pre-triggering or post-triggering when a time base between 20ms/cm and 1µs/cm is selected. The pre­triggering or post-triggering will be automatically switched off (PT0%), with larger time coefficients (100s/cm to 50ms/cm) in order to avoid excessive waiting times. If it is required to measure with pretrigger or post-trigger in this time base range, one should select single shot (SINGLE = SGL).
In XY digital mode the RFR-LED lights. It indicates a continuous, trigger independent signal acquisition. The trigger circuit is switched off.
The accuracy of the mean value evaluation increases as the number the number of signal acquisition scans used for evaluation is increased. One can select the number between 2 and 512. The selected setting is displayed in the readout. Of course, with increasing accuracy the time required for this also increases.
To select a different value briefly press both STOR. MODE pushbuttons simultaneously. The AV... display in the readout flashes indicating the setting mode. Now, the value can be changed by briefly pressing the upper or lower STOR. MODE button. The setting mode can be exited by again briefly pressing the two buttons simultaneously. The setting mode will also be switched off automatically if none of the two buttons is actuated during about 10 seconds.
The averaging begins anew after briefly pressing the
SINGLE (10) pushbutton (RESET-function).
Attention! The pretrigger or post-trigger will be automatically switched off (PT0%) in the time base range from 100s/ cm to 50ms/cm.
(9) ROL - indicates ROLL mode.
In ROLL mode the ROL-LED is lit and the readout displays “ROL”.
In this mode, the memory contents and thus also the signal display, are continuously updated. Because signal capture is untriggered, no idle states arise while waiting for a new trigger event to start signal capture. With each signal sampling the new value is shown on the right-hand edge of the screen, while the previously captured data are shifted to the left. The leftmost value is shifted out of the memory and lost.
(9) ENV - is the abbreviation for ENVELOPE operation.
In this mode the minimum and maximum values of the signal during several signal acquisitions will be determined and displayed. Except for this display, the ENVELOPE operation is identical to the refresh operation.
Changes in the signal are easier to measure and are more visible in ENVELOPE operation. This is valid not only for amplitude changes but also for frequency variations (Jitter).
The ENVELOPE evaluation begins anew when the SIN-
GLE (10) button is pressed briefly, to actuate the RESET (RES) function.
Attention! The pretrigger or post-trigger will be automatically switched off (PT0%) in the time base range from 100s/ cm to 50ms/cm.
(9) AVM - indicates Average (mean value) mode.
This operation is effective when the AVM-LED lights up
and the readout displays AV... .
In this case also several signal acquisition scans are required; hence, it is similar to Refresh operation. The signal is averaged over the several acquisitions so that amplitude variations ( e.g. noise) and frequency variations (Jitter) are minimized or eliminated in the display. The basic mode ”AV4” is effective when the oscilloscope is switched on.
The recording can be stopped at any time by selecting the HOLD (7) function.
ROLL mode can only be used with time coefficients from 100s/div to 50ms/div, as lower time coefficients (faster time base speeds) are impractical.
If the time base is set to values between 20ms/div and 1µs/div and ROLL mode is selected, the time base will be automatically set to 50ms/cm. The time deflection coefficient set previously before switching to ROLL mode will be internally stored (e.g. 20ms/cm). If ROLL mode has been selected inadvertently and the TIME/DIV. knob has not been changed, the time base will be automatically set to the internally stored coefficient when switching from ROLL to AVERAGE mode.
(10) SINGLE - Pushbutton with two functions and associated
LEDs.
SINGLE
Pressing and holding the SINGLE pushbutton switches between SINGLE and:
1. storage mode Yt (time base) or XY operation or
2. analog mode Yt (time base) operation, dependent on the actual instrument setting.
In this operating mode a single signal acquisition process or sweep can be started with a trigger, providing the trigger circuit has been previously activated with RESET.
12
Subject to change without notice
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