Megaimpulse PICOSECOND PPM0731 User manual

PICOSECOND
PULSE GENERATOR MODULE
PPM0731
USER MANUAL
© 2020 Megaimpulse Ltd.

Copyright © 2020 MEGAIMPULSE Ltd. All Rights Reserved.
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APPEAR IN THIS MANUAL, INCLUDING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.
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intent to inf inge.
Megaimp lse Ltd. contact information
Add ess: 26 Polytechnicheskaya st ., St. Pete sbu g, 194021 Russia
www: http://www.megaimpulse.com
e-mail: mp@powe .ioffe. ssi. u
fax: [phone]

CONTENTS
Safety manual .............................................................................................. 2
Package content ........................................................................................... 3
Gene al view of picosecond pulse gene ato .................................................. 3
Desc iption of the gene ato ope ation .......................................................... 4
Technical specification ................................................................................. 6
Top, f ont and ea panels view ..................................................................... 7
Putting the gene ato into ope ation .............................................................. 8
T igge ing of the gene ato ........................................................................... 10
Wa anty ...................................................................................................... 11
PPM0731 User Manual 1

SAFETY MANUAL
Electrical safety
 PPM0731 pulse gene ato module is high voltage equipment. Please be
ve y ca eful and ope ate by qualified pe sonnel only.
 The e is a isk of elect ic shock, st ong elect omagnetic inte fe ence,
damage of the gene ato , o othe elect onic equipment in case of imp ope
use.
 It is st ongly p ohibited to switch on the gene ato without an output
coaxial cable. We ecommend using at least 50 centimete s length coaxial
cable connected between the gene ato and the load (antenna o fi st
attenuato ) to p event pe manent damage to the gene ato . The e is a isk of
elect ical a cing on the open HV coaxial connecto and damage to the
output ci cuit of the gene ato .
 When adding o emoving the gene ato to o f om the system, ensu e that
the powe supply is unplugged (in OFF state). Please apply powe supply
only afte connecting output and input coaxial cables.
 Please p ovide sufficient f ee space and allow f ee ai flow a ound the
gene ato fo good cooling in case of long time ope ation at a high
epetition ate.
Operation safety
 Please ead this manual befo e installing and using the gene ato .
 Befo e using the p oduct, make su e that all the cables a e applicable and
not damaged. High voltage connecto s should be clean and d y, f ee f om
dust, di t, and any obstacles.
 To avoid sho t ci cuits, keep metal pa ts like clips, sc ews, and staples
away f om the gene ato .
 The gene ato is designed fo ope ation in no mal labo ato y conditions.
Avoid dust, humidity, and tempe atu e ext emes. Do not place the
gene ato in any place whe e it may become wet.
 Place the gene ato on a stable su face.
 If you encounte any technical p oblem with the gene ato , please contact
Megaimpulse Ltd. Do not t y to epai the gene ato by you self.
MEGAIMPULSE LTD. 2

PACKAGE CONTENT
Please check the package fo the following items:
 PPM0731 picosecond pulse gene ato module (he einafte "gene ato ")
 Dual voltage AC/DC switching powe conve te :
AC 85V..264V, 47Hz..63Hz / DC +24V, 0.6A; DC +160V, 0.3A;
 Semi igid coaxial cable assembly N connecto /SM141 cable/open fo the
output pulses feeding and connection to the load by solde ing o optional
connecto ;
 Coaxial cable assembly SMA connecto /RG316 cable/SMA connecto
fo the input t igge ing signal feeding;
 Use manual (p inted o elect onic ve sion).
Fig.1. Gene al view of PPM0731 picosecond pulse gene ato module.
PPM0731 User Manual 3

DESCRIPTION OF THE GENERATOR OPERATION
PPM0731 gene ates picosecond ise time unipola high voltage pulses
with up to 7kV amplitude and high epetition ate. It is made as a compact pulse
gene ato module (head) with an exte nal powe supply and exte nal t igge ing.
The exte nal dual voltage DC powe supply is included in the standa d
package togethe with fou wi es DC powe supply cable. If the optional DC
powe supply with optional supply cable is used, then connect it acco ding to the
ma ks.
 The gro nd wires of the power s pply cable are marked by black
color. Low voltage and high voltage s pply wires are marked by the
labels.
The contact pins of the powe supply connecto a e the following:
Pin 1 – GND (g ound etu n DC +24V)
Pin 2 – DC +24V low voltage supply
Pin 3 – GND (g ound etu n DC +160V)
Pin 4 – DC +160V high voltage supply
The typical output pulse wavefo m is shown in Fig.2. No mally the
gene ato should ope ate with 50 Ohm matched load, fo example, UWB antenna
connected by 50 Ohm impedance coaxial cable.
Fig.2. PPM0731 typical output pulse wavefo m on 50 Ohm matched load.
MEGAIMPULSE LTD. 4 MEGAIMPULSE LTD. 4

 It is strongly prohibited to switch on the generator witho t the load
(with open connector). We recommend sing 50 centimeters length
coaxial cable between the generator and the load (antenna or first
atten ator) to prevent damage to the generator in case of load
breakdown.
Ope ation on unmatched load inevitably esults in eflection f om the
load; pa t of the pulse ene gy etu ns back to the gene ato and may ove heat it.
PPM0731 has ove heating p otection. If the tempe atu e exceeds 55 ºC, then the
ed LED "OVERHEAT" lights on and the t igge ing is blocked. Please cool down
the gene ato and educe the epetition ate if equi ed.
 Please provide free airflow aro nd the generator in case of long time
operation at high freq ency, especially in case of an nmatched load.
The gene ato is t igge ed by the leading edge of the exte nal t igge ing
pulse. The e is no inte nal t igge ing mode. Acceptable t igge ing pulse amplitude
is +3.5V … +5V at 50 Ohm; low t igge ing pulse amplitude leads to unstable
t igge ing and highe output pulse jitte . Recommended t igge ing pulse du ation
is 10 ns ... 200 ns. Pulse ise time should be no mo e than 1 ns. Longe ise time
may esult in inc easing the output pulse jitte . O ange LED "SYNC IN" lights on
in case of successful t igge ing.
The gene ato has inte nal ove f equency p otection. If the f equency of
the t igge ing pulses exceeds the maximum, then the gene ato blocks the
t igge ing and ed LED “OVERLOAD” lights on. The same occu s in the case of
a ve y long t igge ing pulse. Please educe the f equency of the t igge ing pulses
and/o t igge ing pulse width.
Two fans a e used fo the cooling of the gene ato . If the tempe atu e is
low, then the fans a e stopped. The otation speed of the fans inc eases with
inc easing the tempe atu e. The efo e, the cooling system stabilizes the
tempe atu e of the gene ato ; this imp oves the stability of the output pulse
wavefo m and educes tempe atu e d ift.
PPM0731 User Manual 5

TECHNICAL SPECIFICATION OF PPM0731 PICOSECOND PULSE
GENERATOR MODULE 1)
Output pulse amplitude 2) 6 … 7 kV
Pulse pola ity and wavefo m Positive, fast rise, short peak,
exponential decay
Output connecto and load impedance 50 Ohm
Pulse ise time (fast pa t) < 200 ps
Pulse width (FWHM) < 500 ps
Max epetition ate (continuous) 10 kHz
Jitte (RMS) < 20 ps
Jitte (peak-to-peak) < 100 ps
Inte nal delay (f om leading edge of
t igge ing pulse to output pulse) ~ 170 ns
T igge ing External only
Input t igge ing pulse connecto SMA
T igge ing pulse pa amete s +5V amplit de on 50 Ohm,
10 ns ... 200 ns width, 1ns rise time
Powe supply +24V, 0.3A;+160V, 0.3A
Size 250 х 130 х 80 mm3
Ope ation tempe atu e 0 °C.. +50°C
1) All the pa amete s a e measu ed afte the ope ation of the gene ato within 10
minutes at 5 kHz epetition ate.
2) Output pulse amplitude inc eases with inc easing of the epetition ate and may
change within ±10% depending on the tempe atu e and ope ation egime.
MEGAIMPULSE LTD.

TOP VIEW
SIDE VIEW
LEFT AND RIGHT VIEW
1 – cont ol LED (f om top to bottom)
+24V DC (g een) – low voltage +24V DC powe supply is applied
+HV DC (g een) – high voltage +160V DC powe supply is applied
SYNC IN (o ange) – t igge ing of the gene ato
OVERHEAT ( ed) – too high tempe atu e
OVERLOAD ( ed) – too high epetition ate
2 – Input t igge ing SMA connecto
3 – Powe supply connecto
4 – 4x mounting holes 4.2 mm dia, 222x118mm footp int
5 – Output HV N-type connecto
5
4
PPM0731 User Manual 7
1
2
3

PUTTING THE GENERATOR INTO OPERATION
 Please follow strictly the described steps. It helps to prevent damage to
the generator and other eq ipment.
Step 1.
Unpack the gene ato and check the p esence into the package of the following
items:
- PPM0731 pulse gene ato ;
- Dual voltage AC/DC switching powe supply conve te with the powe
supply cables;
- Semi igid coaxial cable assembly N_connecto /SM141_cable/open fo
the output pulses feeding;
- Coaxial cable assembly SMA/RG316_cable/SMA fo the input t igge ing
pulses feeding.
Step 2.
 In case of using standa d AC/DC switching powe supply conve te :
Connect it to the gene ato and powe supply outlet. Check the levels of
the low voltage and the high voltage powe supplies and adjust the
voltage levels by the co esponding potentiomete s, if equi ed.
 In case of using alte native powe supply:
Please set the exte nal powe supplies acco ding to the ecommended low
voltage and high voltage levels befo e connecting to the gene ato .
Step 3.
Connect the output semi igid coaxial cable and the load to the gene ato .
Connect the t igge ing pulse gene ato by input coaxial cable.
Attach fou wi es DC powe supply cable in case of using the alte native powe
supply. The g ound wi es a e ma ked by black colo . Low voltage and high
voltage supply wi es a e ma ked by the labels.
Step 4.
Switch on (plug) powe supply. Both g een LED “+24V DC” and “+HV DC”
should light on. Set the exte nal t igge ing pulses f equency to 1 kHz, pulse
amplitude set to +5V, pulse width set within 10ns ... 200ns. Apply t igge ing
pulses, o ange LED “SYNC IN” should light on.
High voltage output pulses should be gene ated. Please check them. Set the
exte nal t igge ing pulses f equency as equi ed, but below o equal to the
maximum epetition ate.
PPG-5/1 and PPG-7/10 picosecond pulse generators user manual 9 MEGAIMPULSE LTD. 8

 Please pay attention that most of the standard GHz range coaxial
atten ators are not s itable for direct registration of o tp t p lses
beca se of extremely high peak power. Even 100W and more power
atten ators will be broken inevitably. We recommend sing of 142 series
Barth Electronics atten ator (for the freq encies below 5 kHz) as the first
atten ator connected j st to the generator o tp t or se a high voltage
directional co pler.
The gene ato is designed fo the long time ope ation at a max epetition ate. But
it can be ove heated in case of unmatched load and high ambient tempe atu e.
Please p ovide f ee ai flow a ound the gene ato fo good cooling. The
tempe atu e of the gene ato should be below 55 °C. Reduce the epetition ate
and/o imp ove the ai flow in case of ove heating.
If the f equency of the t igge ing pulses is too high, then the ed LED
“OVERLOAD” lights on and the gene ato stops the ope ation. Please educe the
f equency of the t igge ing pulses, LED “OVERLOAD” lights off and the
gene ato continues the ope ation automatically.
PPM0731 User Manual 9

TRIGGERING OF THE GENERATOR
The ecommended t igge ing pulse wavefo m is shown in Fig. 3. Nominal
t igge ing pulse amplitude is +5V on 50 Ohm, pulse du ation should be within
10 ns ... 200 ns, ise time should be 1 ns o less. Longe ise time may esult in
inc easing of the output pulse jitte .
Fig. 3. Recommended t igge ing pulse wavefo m.
MEGAIMPULSE LTD. 10

WARRANTY
Please see you sales ag eement to dete mine the wa anty pe iod and wa anty
te ms. The gene ato has wa anty seals.
 Removing of the warranty seals terminates the warranty.
PPM0731 User Manual 11