ORBIT FR 0.1 to 2 GHz Pulse Modulator: FR8205 - Manual

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0.1 to 2 GHz Pulse Modulator FR8205
If you are measuring RCS or antenna patterns
below 2 GHz in a high clutter or high multi-path
environment, you should consider the benefits
provided by the FR8205 Pulse Modulator.
Providing Gated-CW RCS Measurements at
VHF and UHF.
The FR8205 Pulse Modulator is a unique
instrument which allows low frequency RCS
measurements to be performed indoors using a
single transmit-receive antenna. By combining
high power capability with excellent pulse and
gate isolation, very low RCS levels can be
measured anywhere within the 100 MHz to 2
GHz frequency range in a single test. In addition,
the FR8205 achieves outstanding measurement
stability for maximum clutter subtraction levels.
The FR8205 is fully compatible with the HP
8511A Frequency Converter. The FR8205 pulse
modulator prevents the high levels of RF energy
returned from the monostatic feed antenna from
causing the familiar "IF OVERLOAD" errors. At
the same time, the FR8205 supports Ramp
Mode operation allowing very fast frequency
sweeps (under 500 ms). For RCS imaging (SAR
or ISAR) over the 0.1 to 2 GHz frequency range,
the FR8205 Pulse Modulator has proven to be
invaluable.
The FR8205 is also fully compatible with the
dual-source configurations of the Agilent 8510
and Agilent 8530A. Using the fundamentally-
mixed frequency converters such as the Agilent
85310A, -115 dBm system typical sensitivity
levels are achieved while simultaneously
transmitting +23 dBm peak power RF pulses.
The Goal: Clutter Reduction! The design of the
FR8205 Pulse Modulator capitalizes on ORBIT/
FR's in-depth experience in measuring RCS at
ranges under 200 feet and at frequencies below
2 GHz. On this type of range, clutter is the main
cause of poor RCS measurement sensitivity and
measurement error. For this reason, the FR8205
provides extremely fast receive gate speeds (2
nS typical), and very high stability.
High Transmit Power From Built In Amplifier
The FR8205 uses a an internal power amplifier
covering the entire 0.1 to 2 GHz band without
band switching. For monostatic applications, the
FR8205 incorporates transmit noise blanking
during the inter-pulse period to ensure a low
system noise floor.
Completely Protected Receive Stage
The FR8205 incorporates design elements that
protect the receive stage against damage due to
high energy levels coupled to the receive port.
This not only protects against damage, but also
provides rapid recovery times, allowing radar-
target separations as short as 30 feet.
Low Spurious Signal Levels
Through a careful design ORBIT/FR eliminates
the impact of video feedthrough on the
measurement accuracy. This is especially critical
for RCS measurements requiring clutter
subtraction levels in excess of 20 dB.
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