Avtech AVMH-1A-C User manual

INSTRUCTIONS
MODEL AVMH-1A-C
10 VOLTS, 25 MHz
IMPULSE GENERATOR
WITH 130 – 250 ps PULSE WIDTH
SERIAL NUMBER ____________
A V T E C H E L E C T R O S Y S T E M S L T D .
N A N O S E C O N D W A V E F O R M E L E C T R O N I C S
S I N C E 1 9 7 5
P.O. BOX 265
OGDENSBURG, NY
U.S.A. 13669-0265
TEL [phone] (USA & Canada) or [phone] (Intl)
FAX [phone] (USA & Canada) or [phone] (Intl)
[e-mail] - http //www.avtechpulse.com/
X
BOX 5120, LCD MERIVALE
OTTAWA, ONTARIO
CANADA K2C 3H5

WARRANTY
Avtech Electrosystems Ltd. warrants products of its manufacture to be free from
defects in material and workmanship under conditions of normal use. If, within
one year after delivery to the original owner, and after prepaid return by the
original owner, this Avtech product is found to be defective, Avtech shall at its
option repair or replace said defective item. This warranty does not apply to
units which have been dissembled, modified or subjected to conditions
exceeding the applicable specifications or ratings. This warranty is the extent of
the obligation assumed by Avtech with respect to this product and no other
warranty or guarantee is either expressed or implied.
TECHNICAL SUPPORT
Phone [phone] (USA & Canada) or [phone] (International)
Fax [phone] (USA & Canada) or [phone] (International)
E-mail [e-mail]
World Wide Web http //www.avtechpulse.com
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TABLE OF CONTENTS
WARRANTY......................................................................................................................2
TECHNICAL SUPPORT....................................................................................................2
TABLE OF CONTENTS....................................................................................................3
INTRODUCTION...............................................................................................................5
AVAILABLE OPTIONS............................................................................................................ 5
SPECIFICATIONS.............................................................................................................6
REGULATORY NOTES.....................................................................................................7
FCC PART 18..........................................................................................................................7
EC DECLARATION OF CONFORMITY...................................................................................7
DIRECTIVE 2002/95/EC (RoHS).............................................................................................8
DIRECTIVE 2002/9 /EC (WEEE)............................................................................................8
AC POWER SUPPLY REGULATORY NOTES........................................................................9
INSTALLATION...............................................................................................................10
VISUAL CHECK.................................................................................................................... 10
POWER RATINGS.................................................................................................................10
CONNECTION TO THE POWER SUPPLY............................................................................10
PROTECTION FROM ELECTRIC SHOCK............................................................................11
ENVIRONMENTAL CONDITIONS.........................................................................................12
FUSES.............................................................................................................................13
AC FUSE REPLACEMENT...................................................................................................13
DC FUSE REPLACEMENT...................................................................................................14
FUSE RATINGS..................................................................................................................... 14
FRONT PANEL CONTROLS..........................................................................................15
REAR PANEL CONTROLS............................................................................................17
GENERAL INFORMATION.............................................................................................18
BASIC TEST ARRANGEMENT.............................................................................................18
BASIC PULSE CONTROL....................................................................................................18
AMPLITUDE INTERACTION.................................................................................................19
POLARITY INVERSION.........................................................................................................19
MINIMIZING WA EFORM DISTORTIONS.....................................................................20
USE 50Ω TRANSMISSION LINES AND LOADS...................................................................20
USE LOW-INDUCTANCE LOADS.........................................................................................20
3

PRE ENTING DAMAGE................................................................................................20
OPTIONS.........................................................................................................................21
-OS OPTION.......................................................................................................................... 21
-M OPTION............................................................................................................................21
MECHANICAL INFORMATION......................................................................................22
TOP COVER REMOVAL.......................................................................................................22
ELECTROMAGNETIC INTERFERENCE..............................................................................22
MAINTENANCE..............................................................................................................23
REGULAR MAINTENANCE...................................................................................................23
CLEANING............................................................................................................................23
WIRING DIAGRAMS.......................................................................................................24
WIRING OF AC POWER....................................................................................................... 24
PCB 158P - LOW VOLTAGE POWER SUPPLY, 1/3.............................................................25
PCB 158P - LOW VOLTAGE POWER SUPPLY, 2/3.............................................................2
PCB 158P - LOW VOLTAGE POWER SUPPLY, 3/3.............................................................27
MAIN WIRING........................................................................................................................28
PERFORMANCE CHECK SHEET.................................................................................29
Manual Reference /fileserver2/officefiles/instructword/avmh/AVMH-1A-C,ed1.odt.
Last modified May 22, 2015.
Copyright © 2015 Avtech Electrosystems Ltd, All Rights Reserved.
4

INTRODUCTION
The AVMH-1A-C is a high performance instrument capable of generating up to 10V into
50Ω loads at repetition rates up to 25 MHz. The output pulse width may be adjusted
from < 130 ps to > 250 ps.
Instruments with the "-P" model suffix can generate up to +10V, whereas instruments
with the "-N" model suffix can generate up to -10V.
Instruments with the "-P-PN" suffix generate up to +10V at the main output, and are
supplied with an inverting transformer that can be installed on the output to generate a
negative signal.
Instruments with the "-N-PN" suffix generate up to -10V at the main output, and are
supplied with an inverting transformer that can be installed on the output to generate a
positive signal.
The output is designed to drive 50Ω loads. (A 50Ω load is required for proper
operation.) The output is AC-coupled.
This instrument is intended for use in research and development laboratories.
AVAILABLE OPTIONS
The AVMH-1A-C is available with several options
-M Option a monitor output is provided.
-OS Option an externally generated DC offset can be added to the output.
5

SPECIFICATIONS
Model1AVMH-1A-C
Max.5 amplitude (50Ω load4) 10 V
Pulse width 130 - 250 ps
Pulse width measured at 50% (FWHM)
PRF, internal trigger
external trigger
1 kHz - 25 MHz
0 - 25 MHz
Polarity2Positive or negative or both (specify)
Propagation delay ≤ 40 ns (Ext trig in to pulse out)
Jitter ± 15 ps (Ext trig in to pulse out)
DC offset Optional3 Apply the required externally-generated DC offset to
back-panel solder terminals (+50 Volts, 250 mA max)
Trigger required
(ext trig mode) TTL-level (Low 0V, High +3V to +5V), ≥ 10 ns, RIN = 50Ω7.
Sync output +3 Volts, width varies with PRF (always > 10 ns), drives ≥ 50Ω
Sync delay Variable 0 to 80 ns, Sync out to pulse out
Monitor output Optional8. Provides a ÷11 (-21 dB) attenuated
coincident replica of the main output, into 50 Ohms.
Connectors Out, Monitor SMA, Trig BNC
Power requirement 100 - 240 Volts, 50 - 60 Hz
Dimensions H×W×D 100 x 215 x 375 mm (3.9” x 8.5” x 14.8”)
Chassis material Anodized aluminum, with gray plastic trim.
Temperature range +5°C to +40°C
1) -C suffix indicates stand-alone lab instrument with internal clock and line powering. (See http //www.avtechpulse.com/formats for additional details of the basic
instrument formats).
2) Indicate desired polarity by suffixing model number with -P or -N (i.e. positive or negative) or -P-PN or -N-PN for dual polarity option where the suffix preceding -PN
indicates the polarity at the mainframe output port.
3) For DC offset option add suffix -OS.
4) A 50 Ohm load is required. Other loads may damage the instrument. Consult Avtech ([email protected]) if you need to drive other load impedances.
5) For operation at amplitudes of less than 20% of full-scale, best results will be obtained by setting the amplitude near full-scale and using external attenuators on the
output.
6) Maximum amplitude falls by 10% for PRF above 20 MHz.
7) An input impedance of ≥1 kΩ can also be provided (-Z1K option).
8) For monitor option add the suffix -M to the model number.
6

REGULATORY NOTES
FCC PART 18
This device complies with part 18 of the FCC rules for non-consumer industrial,
scientific and medical (ISM) equipment.
This instrument is enclosed in a rugged metal chassis and uses a filtered power entry
module (where applicable). The main output signal is provided on a shielded connector
that is intended to be used with shielded coaxial cabling and a shielded load. Under
these conditions, the interference potential of this instrument is low.
If interference is observed, check that appropriate well-shielded cabling is used on the
output connectors. Contact Avtech ([e-mail]) for advice if you are unsure
of the most appropriate cabling. Also, check that your load is adequately shielded. It
may be necessary to enclose the load in a metal enclosure.
If any of the connectors on the instrument are unused, they should be covered with
shielded metal “dust caps” to reduce the interference potential.
This instrument does not normally require regular maintenance to minimize interference
potential. However, if loose hardware or connectors are noted, they should be
tightened. Contact Avtech ([e-mail]) if you require assistance.
EC DECLARATION OF CONFORMITY
We Avtech Electrosystems Ltd.
P.O. Box 5120, LCD Merivale
Ottawa, Ontario
Canada K2C 3H5
declare that this pulse generator meets the intent of Directive 2004/108/EG for
Electromagnetic Compatibility. Compliance pertains to the following specifications as
listed in the official Journal of the European Communities
EN 50081-1 Emission
EN 50082-1 Immunity
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and that this pulse generator meets the intent of the Low Voltage Directive 72/23/EEC
as amended by 93/68/EEC. Compliance pertains to the following specifications as
listed in the official Journal of the European Communities
EN 61010-1 2001 Safety requirements for electrical equipment for
measurement, control, and laboratory use
DIRECTIVE 2002/95/EC (RoHS)
This instrument is exempt from Directive 2002/95/EC of the European Parliament and
of the Council of 27 January 2003 on the Restriction of the use of certain Hazardous
Substances (RoHS) in electrical and electronic equipment. Specifically, Avtech
instruments are considered "Monitoring and control instruments" (Category 9) as
defined in Annex 1A of Directive 2002/96/EC. The Directive 2002/95/EC only applies to
Directive 2002/96/EC categories 1-7 and 10, as stated in the "Article 2 - Scope" section
of Directive 2002/95/EC.
DIRECTIVE 2002/96/EC (WEEE)
European customers who have purchased this equipment directly from Avtech will have
completed a “WEEE Responsibility Agreement” form, accepting responsibility for
WEEE compliance (as mandated in Directive 2002/96/EC of the European Union and
local laws) on behalf of the customer, as provided for under Article 9 of Directive
2002/96/EC.
Customers who have purchased Avtech equipment through local representatives
should consult with the representative to determine who has responsibility for WEEE
compliance. Normally, such responsibilities with lie with the representative, unless
other arrangements (under Article 9) have been made.
Requirements for WEEE compliance may include registration of products with local
governments, reporting of recycling activities to local governments, and financing of
recycling activities.
8

AC POWER SUPPLY REGULATORY NOTES
This instrument converts the AC input power to the +24V DC voltage that powers the
internal circuitry of this instrument using a Tamura AAD130SD-60-A switching power
supply. According to the manufacturer, the Tamura AAD130SD-60-A has the following
certifications
UL60950-1
IEC60950 -1
CSA C22.2 No. 60950- 1
EN60950 -1
and is compliant with
EN61000-3-2
EN61000-4-2 Level 2
EN61000-4-2 Level 3 (Air Only)
EN61000-4-4 Level 3
EN61000-4-5 Level 3
EN61000-4-11
CISPR 11 and 22 FCC Part 15 Class B (conducted)
9

INSTALLATION
VISUAL CHECK
After unpacking the instrument mainframe and the transformer module, examine to
ensure that they have not been damaged in shipment. Visually inspect all connectors,
knobs, and handles. Confirm that a power cord and an instrumentation manual (this
manual), are with the instrument. If the instrument has been damaged, file a claim
immediately with the company that transported the instrument.
POWER RATINGS
This instrument is intended to operate from 100 - 240 V, 50 - 60 Hz.
The maximum power consumption is 57 Watts. Please see the “FUSES” section for
information about the appropriate AC and DC fuses.
This instrument is an “Installation Category II” instrument, intended for operation from a
normal single-phase supply.
CONNECTION TO THE POWER SUPPLY
An IEC-320 three-pronged recessed male socket is provided on the back panel for AC
power connection to the instrument. One end of the detachable power cord that is
supplied with the instrument plugs into this socket. The other end of the detachable
power cord plugs into the local mains supply. Use only the cable supplied with the
instrument. The mains supply must be earthed, and the cord used to connect the
instrument to the mains supply must provide an earth connection. (The supplied cord
does this.)
Warning Failure to use a grounded outlet may result in injury or death due to
electric shock. This product uses a power cord with a ground connection. It must be
connected to a properly grounded outlet. The instrument chassis is connected to the
ground wire in the power cord.
The table below describes the power cord that is normally supplied with this instrument,
depending on the destination region
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Destination Region Description Option Manufacturer Part Number
United Kingdom, Hong Kong,
Singapore, Malaysia
BS 1363,
230V, 50 Hz -AC00 Qualtek 370001-E01
Australia, New Zealand AS 3112 2000,
230-240V, 50 Hz -AC01 Qualtek 374003-A01
Continental Europe, Korea,
Indonesia, Russia
European CEE 7/7
“Schuko” 230V, 50 Hz -AC02 Qualtek 364002-D01
North America, Taiwan NEMA 5-15,
120V, 60 Hz -AC03 Qualtek 312007-01
Switzerland SEV 1011,
230V, 50 Hz -AC06 Qualtek 378001-E01
South Africa, India SABS 164-1,
220-250V, 50 Hz -AC17 Volex 2131H 10 C3
Japan JIS 8303,
100V, 50-60 Hz -AC18 Qualtek 397002-01
Israel SI 32,
220V, 50 Hz -AC19 Qualtek 398001-01
China GB 1002-1,
220V, 50 Hz -AC22 Volex 2137H 10 C3
PROTECTION FROM ELECTRIC SHOCK
Operators of this instrument must be protected from electric shock at all times. The
owner must ensure that operators are prevented access and/or are insulated from
every connection point. In some cases, connections must be exposed to potential
human contact. Operators must be trained to protect themselves from the risk of
electric shock. This instrument is intended for use by qualified personnel who recognize
shock hazards and are familiar with safety precautions required to avoid possibly injury.
In particular, operators should
1. Keep exposed high-voltage wiring to an absolute minimum.
2. Wherever possible, use shielded connectors and cabling.
3. Connect and disconnect loads and cables only when the instrument is turned off.
4. Keep in mind that all cables, connectors, oscilloscope probes, and loads must
have an appropriate voltage rating.
5. Do not attempt any repairs on the instrument, beyond the fuse replacement
procedures described in this manual. Contact Avtech technical support (see
page 2 for contact information) if the instrument requires servicing. Service is to
be performed solely by qualified service personnel.
11

ENVIRONMENTAL CONDITIONS
This instrument is intended for use under the following conditions
1. indoor use;
2. altitude up to 2 000 m;
3. temperature 5 °C to 40 °C;
4. maximum relative humidity 80 % for temperatures up to 31 °C decreasing
linearly to 50 % relative humidity at 40 °C;
5. Mains supply voltage fluctuations up to ±10 % of the nominal voltage;
6. no pollution or only dry, non-conductive pollution.
12

FUSES
This instrument contains four fuses. All are accessible from the rear-panel. Two protect
the AC prime power input, and two protect the internal DC power supplies. The
locations of the fuses on the rear panel are shown in the figure below
AC FUSE REPLACEMENT
To physically access the AC fuses, the power cord must be detached from the rear
panel of the instrument. The fuse drawer may then be extracted using a small flat-head
screwdriver, as shown below
13
Fuse
Drawer
Pry out the fuse
drawer using a
screwdriver.
Fuses #1 and #2
(AC fuses)
Fuse #4
(DC fuse)
Fuse #3
(DC fuse)

DC FUSE REPLACEMENT
The DC fuses may be replaced by inserting the tip of a flat-head screwdriver into the
fuse holder slot, and rotating the slot counter-clockwise. The fuse and its carrier will
then pop out.
FUSE RATINGS
The following table lists the required fuses
Fuses
Nominal
Mains
Voltage
Rating Case Size
Recommended Replacement Part
Littelfuse Part
Number
Digi-Key Stock
Number
#1, #2 (AC) 100-240V 0.5A, 250V,
Time-Delay 5×20 mm 0218.500HXP F2416-ND
#3 (DC) N/A 1.0A, 250V,
Time-Delay 5×20 mm 0218001.HXP F2419-ND
#4 (DC) N/A 0.8A, 250V,
Time-Delay 5×20 mm 0218.800HXP F2418-ND
The recommended fuse manufacturer is Littelfuse (http //www.littelfuse.com).
Replacement fuses may be easily obtained from Digi-Key (http //www.digikey.com) and
other distributors.
14

FRONT PANEL CONTROLS
1. POWER Switch. This is the main power switch.
2. OVERLOAD Indicator. When the instrument is powered, this indicator is normally
green, indicating normal operation. If this indicator is yellow, an internal automatic
overload protection circuit has been tripped. If the unit is overloaded (by operating
at an exceedingly high duty cycle or by operating into a very low impedance), the
protective circuit will disable the output of the instrument and turn the indicator light
yellow. The light will stay yellow (i.e. output disabled) for about 5 seconds after
which the instrument will attempt to re-enable the output (i.e. light green) for about 1
second. If the overload condition persists, the output will be disabled again (i.e. light
yellow) for another 5 seconds. If the overload condition has been removed, the
instrument will resume normal operation.
This overload indicator may flash yellow briefly at start-up. This is not a cause for
concern.
3. PRF Range Switch and Fine Dial. This switch sets the pulse repetition frequency
(PRF) range of the internal oscillator. The marked value of each position is the
upper limit of the range, approximately. The fine dial directly below the switch varies
the PRF within the set range. When set to the “EXT” position, the instrument is
triggered by externally-generated pulses applied to the TRIG input.
15
2
13
5
4
6
7
9
8

4. DELAY Control. Controls the relative delay between the reference output pulse
provided at the SYNC output and the main output. This delay is variable over the
range of 0 to 50 ns, approximately. At high frequencies, this delay should be kept
nearly fully counter-clockwise, so that the delay does not exceed the period
(otherwise, the triggering may stop). The variable delay circuitry only functions in the
internal trigger mode. The delay is not adjustable when triggering externally.
5. TRIG Input. The external trigger signal is applied at this input when the PRF range
switch is in the “EXT” position.
For standard units, a TTL logic level pulse (i.e., 0V = TTL LOW, +3V to +5V = TTL
HIGH) is required to trigger this input, and the input impedance is 50Ω to ground (or
1kΩ, for units with the -Z1K option).
The input pulse width should be > 10 ns.
6. SYNC Output. This output precedes the main output, and is typically used to trigger an
oscilloscope. When triggering internally, the SYNC pulse width varies, but is always >
10 ns. When triggering externally, the SYNC output is a buffered replica of the TRIG
input. The amplitude is fixed at +3V approximately, and this output will drive 50 Ohms
or higher.
7. Pulse Width Controls. These two dials control the pulse width. The TR dial
determines the position of the impulse rising edge, and the TF dial determines the
position of the impulse falling edge. Used together, they control the pulse width.
8. Amplitude Control. This dial controls the pulse amplitude.
9. OUT Connector. This is the main output. (This output re uires a 50Ω load to function
properly).
16

REAR PANEL CONTROLS
1. AC POWER INPUT. An IEC-320 C14 three-pronged recessed male socket is
provided on the back panel for AC power connection to the instrument. One end of
the detachable power cord that is supplied with the instrument plugs into this
socket.
2. AC FUSE DRAWER. The two fuses that protect the AC input are located in this
drawer. Please see the “FUSES” section of this manual for more information.
3. DC FUSES. These two fuses protect the internal DC power supplies. Please see the
“FUSES” sections of this manual for more information.
4. OS INPUT CONNECTOR. (Present on units with -OS option only.) A DC offset in the
range of ±50V (250 mA max) may be applied to this solder terminal. The DC offset
will appear on the output. When this feature is not used, the OS input should be
connected to ground (using the adjacent GND connector). This is especially
important when driving loads containing a diode.
5. GND CONNECTOR. This solder terminal is connected to ground. It may be used to
ground the OS input connector.
6. M OUTPUT CONNECTOR. (Present on units with -M option only.) This SMA
connector output provides a 20 dB attenuated coincident replica of main output, for
monitoring purposes.
17
2
31
4
5
6
OS GND M

GENERAL INFORMATION
BASIC TEST ARRANGEMENT
The AVMH-1A-C should be tested with a sampling oscilloscope with a bandwidth of at
least 15 GHz to properly observe the high-speed waveform. A typical test arrangement
is shown below
The attenuators are required to prevent damage to the sampling oscilloscope. A 40 dB
attenuator with sufficient voltage rating should be used on the main output.
BASIC PULSE CONTROL
This instrument can be triggered by its own internal clock or by an external TTL trigger
signal. When triggered internally, two mainframe output channels respond to the
trigger OUT and SYNC.
OUT. This is the main output.
SYNC. The SYNC pulse is a 3V, > 10 ns wide reference pulse used to trigger
oscilloscopes or other measurement systems.
These pulses are illustrated below
18
AVTECH
PULSER
MAIN OUTPUT
CONNECTOR
TRIG
CONNECTOR
AC
POWER
ALL CABLES 50 OHM COAXIAL
SAMPLING
OSCILLOSCOPE
BW > 15 GHz
50 OHM INPUT
TRIG
CONNECTOR
40 dB
ATTENUATOR

Figure A
The AVMH-1A-C can also be triggered by a TTL-level pulse applied to the TRIG input.
AMPLITUDE INTERACTION
Some properties of the output pulse may change as a function of the amplitude setting.
For some demanding applications, it may be desirable to use a combination of external
attenuators and the amplitude pot to achieve the desired output amplitude.
POLARITY INVERSION
Instruments with the "-P-PN" suffix generate up to +10V at the main output, and are
supplied with an AVX-2 inverting transformer that can be installed on the mainframe
output. A negative pulse is then obtained at the out port of the AVX-2 module.
Instruments with the "-N-PN" suffix generate up to -10V at the main output, and are
supplied with an AVX-2 inverting transformer that can be installed on the mainframe
output. A positive pulse is then obtained at the out port of the AVX-2 module.
When using the transformer with dual-polarity models with the “-OS” option, the external
offset must be added to the DC terminal of the inverting transformer. Do not apply the
offset to the rear-panel offset terminal on the mainframe (if present).
19
SYNC
(generated by the
internal oscillator)
> 10 ns
MAIN OUTPUT
PULSE WIDTHDELAY
AMPLITUDE,
VARIABLE
3V, FIXED

MINIMIZING WAVEFORM DISTORTIONS
USE 50 Ω TRANSMISSION LINES AND LOADS
Connect the load to the pulse generator with 50Ω transmission lines (e.g. RG-58 or
RG-174 cable).
This instrument requires a 50Ω load for proper operation. It will not properly drive a
high-impedance load. The output stage will be damaged if it is operated into an open
circuit (or any other high impedance). Failures due to improper output loading are not
covered by the warranty.
USE LOW-INDUCTANCE LOADS
Lenz’s Law predicts that for an inductive voltage spike will be generated when the
current through an inductance changes. Specifically, VSPIKE = L × dILOAD/dt, where L is
the inductance, ILOAD is the load current change, and t is time. For this reason, it is
important to keep any parasitic in the load low. This means keeping wiring short, and
using low inductance components. In particular, wire-wound resistors should be
avoided.
PREVENTING DAMAGE
The AVMH-1A-C may fail if triggered at a PRF greater than 25 MHz.
This unit is designed to operate into a load impedance of 50 Ohms and the output
stage will be damaged if it is operated into an open circuit (or any other high
impedance). Failures due to improper output loading are not covered by the warranty.
The lifetime of the switching elements in the pulse generator module is proportional to the
running time of the instrument. For this reason the prime power to the instrument should
be turned off when the instrument is not in use.
20