Surface Concept Preamplifier-CFD User manual
1-Channel & 4-Channel
Preamplier-CFD
Manual
2
Surface Concept GmbH
Am Saegewerk 23a
55124 Mainz
Germany
phone: +49 6131 62716 0
fax: +49 6131 62716 29
email: info@surface-concept.de
web: www.surface-concept.de
All rights reserved. No part of this manual may
be reproduced without the prior permission
of Surface Concept GmbH.
User Manual for the
1-Channel Preamplier-CFD R007
& 4-Channel Preamplier-CFD R011
Manual Version 2.3
Printed on 2020-10-20
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Preamplier-CFD Manual
1 Table of Contents ......................................................................................................................3
2 General Information ................................................................................................................5
2.1 General Information & Safety Instructions................................................................5
2.2 General Overview of the System ..................................................................................5
3 CFD - Principle of Operation .................................................................................................7
3.1 CFD - Principle of Operation...........................................................................................7
4 Technical Specication............................................................................................................9
4.1 Layout of Front Panel........................................................................................................9
4.2 Input/Output Features .................................................................................................. 11
4.2.1 Input Features........................................................................................................ 11
4.2.2 Output Features.................................................................................................... 11
4.2.3 Measurement Parameters ................................................................................. 11
4.3 CFD Adjustment ............................................................................................................. 11
4.3.1 Adjustment of CFD Threshold.......................................................................... 11
4.3.2 Adjustment of Zero Oset................................................................................. 11
4.3.3 Adjustment of the Asymmetry........................................................................ 12
4.3.4 Procedure for Walk Minimization ................................................................... 12
4.4 Power Requirements ..................................................................................................... 12
5 List of Figure ............................................................................................................................13
1 Table of Contents
4
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5
Preamplier-CFD Manual
2 General Information
2.1 General Information & Safety Instructions
This manual is intended to assist users in the operation of the 1-Channel Preamplier-CFD R007 and
4-Channel Preamplier-CFD R011. It is divided into 4 chapters.
Surface Concept strongly recommends reading this manual carefully before operating the Preamplier-
CFD. Surface Concept declines all responsibility for damages or injuries caused by an improper use of
the Module due to negligence on behalf of the User.
2.2 General Overview of the System
The Surface Concept Preamplier-CFD devices are a combination of a preamplier with variable gain (typ.
13dB to 30dB) and a constant fraction discriminator (CFD) housed in a RF-shielded stand-alone (R007) or
19” (R011) housing. The device accepts 1 analog negative or positive input (BNC connector) and produces
1 LVTTL output (BNC connector) and 1 NIM output (LEMO connector) per channel. It is equipped with an
additional monitor output (BNC) for the amplied analog signal.
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Preamplier-CFD Manual
3 CFD - Principle of Operation
3.1 CFD - Principle of Operation
The technique of the constant fraction discriminator (CFD) is based on summing the original input signal
to an inverted signal. The original input signal is delayed but of full height, while the inverted signal is
attenuated.
The resulting signal is fed into a zero-crossing comparator. This allows obtaining precise timing
information that eliminates any walk error, which is induced by constant rise time and varying signal
amplitudes.
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Preamplier-CFD Manual
4 Technical Specication
4.1 Layout of Front Panel
Figure 1: Front Panel of 1-Channel Preamplier-CFD
1
2 3
4
5 6 7
8 9 10
11
12 13 14
Figure 2: Front Panel of 4-Channel Preamplier-CFD
1
Figure 3: Back Panel of 4-Channel Preamplier-CFD
2 3
4
5 6 7 9
10
11
12 13 14
15
16
17
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1. BNC Input for Negative Analogue Signal
2. Regulator for Variable Gain of Preamplier
3. Switch for Pulse Input Polarity (neg. or pos.)
4. BNC Monitor Output for Amplied Analogue Signal
(Recommendation: use AC-coupled measurement mode when observing the signal with an
oscilloscope)
5. Regulator for the Asymmetry (Asy)
6. Regulator for the Zero Oset (Z)
7. CFD Threshold (Th) Regulator
8. 5 PIN Power Connector
9. Lemo Output for CFD NIM Signal
10. BNC Output for CFD LVTTL Signal
11. CFD Operation Monitor LED
12. Monitor Output for the Zero Oset [Z]
13. Monitor Output for the Threshold [Th]
14. Monitor Output for Ground [GND]
15. Power Switch to turn the device ON/OFF. Lighted, when set to ON.
16. Device Ground Connection
17. Power Socket
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Preamplier-CFD Manual
4.2 Input/Output Features
Preamplier Input Signal:
Polarity of Input Signal:
Impedance:
4.2.1 Input Features
2mV - 1V (BNC)
(depending on gain setting)
negative or positive (switchable)
50Ohm
CFD Output Signal per Channel:
Pulse Width of Output Signal (typ.):
Monitor Output:
4.2.2 Output Features
1 LVTTL (BNC), 1 NIM (LEMO)
2.4 (LVTTL), 3ns (NIM)
1 analogue (BNC)
Input Signal Frequency (max.):
CFD Jitter (max.):
CFD Walk (typ.):
Device propagation delay (typ.):
4.2.3 Measurement Parameters
40MHz
20ps
< 40ps (for 20dB amplitude range and while
ambient temperature varies less then 5K)
6.5ns
4.3 CFD Adjustment
The CFD Threshold can be adjusted manually by turning the corresponding potentiometer (marked “Th”
on the front panel). The threshold is getting more sensitive when turning the potentiometer clockwise. It
can be monitored on the corresponding sockets (no. 13 & 14) on the front panel (see Figure 1 & 2).
4.3.1 Adjustment of CFD Threshold
The Zero Oset can be adjusted by turning the corresponding potentiometer (marked “Z” on the front
panel). The Zero Oset is getting more positive when turning the potentiometer clockwise. It can be
monitored on the corresponding sockets (no. 12 & 14) on the front panel (see Figure 1 & 2).
4.3.2 Adjustment of Zero Oset
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The Asymmetry between the inverted input signal and the original input signal can be adjusted by turning
the corresponding potentiometer (marked “Asy” on the front panel). The fraction of the positive pulse is
getting larger, when turning the potentiometer counterclockwise.
4.3.3 Adjustment of the Asymmetry
4.3.4 Procedure for Walk Minimization
The following description gives a procedure of how to minimize the walk for a given amplitude range:
1. Select the amplitude range of pulses, which should be measured (e.g. -60mV to -600mV).
2. Apply pulses of max. Amplitude (within the amplitude range) to the Input of the CFD (e.g. -600mV).
3. Observe the CFD output signal with an oscilloscope and trigger on the falling edge of the output signal.
4. Check the CFD walk by changing the amplitude of the input signal by around 50% (e.g. changing
between -300 and -600mV) and minimize the CFD walk by adjusting the asymmetry.
5. Decrease the amplitude of the input signal by at least 50% (e.g. down to -300mV) and check the CFD
walk for small pulse amplitudes by changing the amplitude of the input signal again (e.g. changing
between -50 and -300mV).
6. Minimize the CFD walk for small pulses by adjusting the zero oset.
4.4 Power Requirements
The 1-Channel Preamplier-CFD is supplied by a wall power supply (input: 100 – 240V, 50 – 60Hz, 1.0A
max) with a maximum output of 15W (+5V, 3A).
Figure 4: View of 5 Pin housing connector of 1-Channel Preamplier-CFD
from outside.
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Preamplier-CFD Manual
5 List of Figure
Figure 1: Front Panel of 1-Channel Preamplier-CFD................................................................................................................................................ 9
Figure 2: Front Panel of 4-Channel Preamplier-CFD................................................................................................................................................ 9
Figure 3: Back Panel of 4-Channel Preamplier-CFD................................................................................................................................................. 9
Figure 2: View of 5 Pin housing connector of 1-Channel Preamplier-CFD from outside......................................................................... 12
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Surface Concept GmbH
Am Sägewerk 23a
55124 Mainz
Germany
phone: +49 6131 62716 0
fax: +49 6131 62716 29
email: info@surface-concept.de
web: www.surface-concept.de
Manufacturer
Product 1-Channel Preamplier-CFD
4-Channel Preamplier-CFD
The above named products comply with the following European directive:
89/336/EEC Electromagnetic Compability Directive, amended by 91/263/ EEC
and 92/31/ EEC and 93/68/EEC
73/23/EEC Low Voltage Equipment Directive, amended by 93/68/EEC
The compliance of the above named product to which this declaration relates is in conformity with the
following standards or other normative documents where relevant:
EN 61000-6-2:2005+AC:2005 Electromagnetic compatibility (EMC):
Generic standards - Immunity for industrial environments
EN 61000-6-4:2007+A1:2011 Electromagnetic compatibility (EMC):
Generic standards - Emission standard for industrial environments
EN 61010-1: 2010 Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use
This declaration does not represent a commitment to features or capabilities of the instrument. The safety notes and regulations
given in the product related documentation must be observed at all times.
For and on behalf of Surface Concept GmbH
Mainz,……01.04.2013………. Legal Signature…………………………………………
(Date) (Dr. Andreas Oelsner)
EC Declaration of Conformity
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