A.H. Systems PAM-0118 Manuel utilisateur
A.H. Systems Model PAM-0118 Pre-Amplifier
PAM-0118
Preamplifier
Operation Manual
A.H. Systems inc. – April 2009
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Advanced Test Equipment Rentals
www.atecorp.com 800-404-ATEC (2832)
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A.H. Systems Model PAM-0118 Pre-Amplifier
TABLE OF CONTENTS
INTRODUCTION
Before Applying Power.....................................................................3
Intended Purposes...........................................................................4
Hazardous F Voltages...................................................................4
ange of Environmental Conditions ................................................5
OPERATING INSTRUCTIONS
Assembly Instructions......................................................................6
Mounting Instructions.......................................................................6
Operating Instructions......................................................................6
GENERAL INSTRUCTIONS
Specifications...................................................................................7
Included Equipment..........................................................................7
Optional Equipment..........................................................................7
Typical Data.....................................................................................8
Conversion Formulas.......................................................................9
MAINTENANCE AND WARRANTY
Maintenance...................................................................................12
Warranty.........................................................................................13
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A.H. Systems Model PAM-0118 Pre-Amplifier
INT ODUCTION
The PAM-0118 broadband preamplifier is an excellent choice for improving
system dynamic range. The performance of this preamplifier will increase your
system sensitivity by at least 35 dB and is ideal for low-amplitude test
measurements. When measuring in the EMC lab or out in the field for general
FI testing, this preamplifier has a rugged compact design.
BEFO E APPLYING POWE
eview this manual and become familiar with this preamplifier and testing
instructions. Verify that the equipment line voltage is compatible with the main
power source.
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A.H. Systems Model PAM-0118 Pre-Amplifier
INTENDED PU POSES
This equipment is intended for general laboratory use in a wide variety of
industrial and scientific applications and designed to be used in the process of
generating, controlling and measuring high levels of electromagnetic adio
Frequency ( F) energy. It is the responsibility of the user to assure that the
device is operated in a location which will control the radiated energy such that
it will not cause injury and will not violate regulatory levels of electromagnetic
interference.
HAZA DOUS F VOLTAGES
The PAM-0118 preamplifier is reliable when operated under specified
conditions; however the use of sensitive, high-performance semiconductors
causes the preamplifier to be susceptible to ESD and EOS. The risk of damage
due to ESD is small, but possible, because the charged object would have to
come in contact with one of the center conductors. It is more likely that EOS
damage will cause the failure of the preamplifier.
ESD – (Electrostatic Discharge)
A discharge of static electricity can degrade or even worse, seriously damage
the preamplifier. There are two kinds of ESD damage that can occur. The worst
being severe resulting in complete failure of the preamplifier. This damage is
relatively easy to create although often expensive and time consuming to fix.
The second kind of damage is less severe and can result in degradation or
weakening of components which will not result in evident failure. This kind of
damage is difficult to detect and often results in faulty or degraded performance.
EOS – (Electrical Overstress)
Precautions against EOS should always be maintained while operating the
preamplifier. It must be emphasized that excessive power applied to the F
input of the preamplifier will damage the input stage. EOS damage can even
occur when storing the preamplifier in areas of strong EMI or FI fields.
Improper connection sequence is another possible source of EOS damage
such as application of F signals to the preamplifier before powering up. When
connecting alternate sources of DC power caution should be made that
excessive Input DC voltage is not applied as this is another source of EOS
damage. Loose connections causing intermittent events can also damage the
preamplifier.
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A.H. Systems Model PAM-0118 Pre-Amplifier
Most common causes of failure:
•Excessive power applied to the F input (such as ESD to the input
connector or antenna connected to the input connector)
•Improper connection sequence (sequence such as application of signals to
the preamplifier before powering up)
•Excessive DC voltage applied
•Storage near strong EMI or FI fields
•Loose connections causing intermittent events
An over voltage at the preamp input will damage the preamplifier. This type of
damage is without fault of A.H. Systems and will void the warranty.
To connect:
1. Apply DC Voltage
2. Connect output load
3. Apply F input
To disconnect:
1. emove F input
2. emove load
3. emove DC voltage
ANGE OF ENVI ONMENTAL CONDITIONS
This equipment is designed to be safe under the following environmental
conditions:
Indoor use
Altitude: up to 2 km
Temperature: 5° C to 40° C
Maximum relative humidity: 80% for temperatures up to 31° C.
Decreasing linearly to 50% at 40° C
Pollution degree 2: Normally non-conductive with occasional
condensation.
DC supply voltage fluctuations not to exceed +/- 10% of the nominal
voltage.
While the equipment will not cause hazardous conditions over this
environmental range, performance may vary.
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A.H. Systems Model PAM-0118 Pre-Amplifier
OPE ATING INST UCTIONS
ASSEMBLY INST UCTIONS
The Model PAM-0118 preamplifier is shipped completely assembled. Simply supply the
required 15 Vdc to the preamplifier.
MOUNTING INST UCTIONS
The Model PAM-0118 is a bench top preamplifier. Ordinarily, the preamplifier should be
used near the test equipment, rather than at the antenna. There are a few exceptions,
however, including:
•Magnetic Loop antennas in quiet locations. These antennas have relatively low
sensitivity or gain. When used in quiet locations, they do not provide much
background noise to the system.
•Long cable runs. If the cable loss is high, performance will improve with the
preamplifier mounted near the antenna.
OPE ATING INST UCTIONS
Operation of the Model PAM-0118 preamplifier is quite simple. The unit is turned on by
first plugging the phone-type plug from an external power supply into the power input
connector. The power supply is then plugged into the appropriate line voltage supply.
Ensure that the preamplifier has sufficient time (15 minutes) to warm up and stabilize.
Pushing the switch to the on position turns on the preamplifier and the power indicator
LED will light. The output signal is taken from the jack marked “OUTPUT” and fed to the
desired amplifier or test equipment. The input signal is connected to the jack marked
“INPUT”.
CAUTION:
The Model PAM-011 preamplifier is not critical in regards to source and load VSWR
and will remain unconditionally stable with any magnitude and phase of source and
load VSWR. However, input signals greater than -30 dBm are not recommended, as
they will saturate the preamplifier and amplitudes higher than +10 dBm will damage
the preamplifier.
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A.H. Systems Model PAM-0118 Pre-Amplifier
GENE AL INFO MATION
SPECIFICATIONS
The PAM-0118 Pre-amplifier specifications:
Power output .....................................+10 dBm at 1 dB compression
Frequency ange..................................................20 MHz – 18 GHz
Gain (typical).............................................................................38 dB
Gain (minimum)........................................................................35 dB
Gain Flatness ...................................................................+/- 2.75 dB
Noise Figure.....................................................................2.5 dB Max
Modulation Capability................................will reproduce AM, FM or
pulse modulation on the
input signal
Primary Power........................................................+15 Vdc, 110 mA
F Connectors...................................................................Type N (f)
Impedance............................................................50 Ω, < 2.5 VSW
Weight ....................................................................................1.1 lbs.
Size (W x H x D)...................................................3.75" x 2.5" x 6.25”
INCLUDED EQUIPMENT
The Model PAM-0118 preamplifier is supplied with an external regulated power supply,
that can be used on 110 – 120 Vac, 60 Hz or 220 – 240 Vac, 50 Hz, and supplies +15
Vdc up to 1 A. The power supply has a standard AC input connector and uses a 2.5mm
coax output connector. The preamplifier has a low voltage indicator that allows you to
power the preamplifier with an external battery supply.
OPTIONAL EQUIPMENT
The following is a recommend accessory list for the Model PAM-0118
preamplifier:
SAC-1 G-0.5
0.5 meter high-frequency, low-loss cable to interconnect the preamplifier to the
receiver or analyzer. This high performance cable is made with the best
materials and precision N-type male connectors. Other connectors are
available and these cables can be made to your specified length.
SAC-1 G-3
3 meter high-frequency, low-loss cable to interconnect the preamplifier to the
antenna or chamber wall. This high performance cable is made with the best
materials and precision N-type male connectors. Other connectors are
available and these cables can be made to your specified length.
Adapters
Need an adapter? We stock those as well.
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A.H. Systems Model PAM-0118 Pre-Amplifier
TYPICAL DATA
The following is typical data of the Model PAM-0118 preamplifier:
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A.H. Systems Model PAM-0118 Pre-Amplifier
CALCULATIONS
EMISSIONS TESTING
Individual calibration data for the log periodic antenna is supplied at appropriate
distances (3, and 10 meter) to comply with various emissions test requirements.
For emissions measurements, add antenna factor plus cable loss to receiver
reading in dBµV to convert to field strength in dBµV/m.
FS = Field Strength in dBµV/m
SA = Spectrum Analyzer or eceiver voltage reading
AF = Antenna Correction Factor
CL = Cable Loss in dB
IMMUNITY TESTING
For Immunity measurements, the generated electric field strength can be
calculated by:
FS = Approximate Field Strength in (V/m)
P = Power in watts
g = Numeric Gain
d = Distance in meters
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A.H. Systems Model PAM-0118 Pre-Amplifier
TYPICAL CONVE SION FO MULAS
dBmW = dBµV – 107
The constant in the above equation is derived as follows. Power is related to voltage according to
Ohm's law. The Log10 function is used for relative (dB) scales, so applying the logarithmic function to
Ohm's law, simplifying, and scaling by ten (for significant figures) yields:
P = V2 /
10Log10[P] = 20Log10[V] – 10Log10[50Ω]
Note, the resistance of 50 used above reflects that F systems are matched to 50Ω. Since F
systems use decibels referenced from 1 mW, the corresponding voltage increase for every 1 mW
power increase can be calculated with another form of Ohm's law:
V = (P )0.5 = 0.223 V = 223000 µV
Given a resistance of 50Ω and a power of 1 mW
20Log10[223000 µV] = 107 dB
The logarithmic form of Ohm's law shown above is provided to describe why the log of the
corresponding voltage is multiplied by 20.
dBmW/m2 = dBµV/m – 115.
The constant in this equation is derived following similar logic. First, consider the pointing vector
which relates the power density (W/m2) to the electric field strength (V/m) by the following equation.
P=|E|2/η
Where η is the free space characteristic impedance equal to 120πΩ. Transforming this equation to
decibels and using the appropriate conversion factor to convert dBW/m2 to dBmW/m2 for power
density and dBV/m to dBµV/m for the electric field, the constant becomes 115.8.
dBµV/m = dBµV + AF
Where AF is the antenna factor of the antenna being used, provided by the antenna manufacturer or
a calibration that was performed within the last year.
V/m = 10{[(dBuV/m)-120]/20}
Not much to this one; just plug away!
dBµA/m = dBµV/m – 51.5
To derive the constant for the above equation, simply convert the characteristic impedance of free
space to decibels, as shown below.
20Log10[120π] = 51.5
A/m = 10{[(dBuA/m)-120]/20}
As above, simply plug away.
dBW/m2 = 10Log10[V/m – A/m]
A simple relation to calculate decibel-Watts per square meter.
dBmW/m2 = dBW/m2 + 30
The derivation for the constant in the above equation comes from the decibel equivalent of the factor
of 1000 used to convert W to mW and vice versa, as shown below.
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