Vaisala RVP900, User Manual

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3.1.3.2 Digital IF Band Pass Design Tool
The digital matched filter computes I and Q interactively using a TTY and oscilloscope for
graphical display.
You can choose the filter's passband width and impulse response length, and RVP
constructs the filter coefficients. You can display the frequency response of the filter and
compare it to the frequency content of the transmitted pulse.
Microwave energy can come from a variety of transmitters such as ground-based, ship-
based, or airborne radars as well as communications links. To minimize the risk of substantial
interference to a weather radar system, RVP supports interference rejection algorithms. See
7.2.5 Interference Filter (page 178) .
The RVP901 IFDR places the WDR
I
and
Q
samples on the Ethernet line, where they are sent
to the computer's processor. The I and Q values are then processed to extract the moment
information ( Z , V , W , and optional polarization parameters).
Using the Digital IF Band Pass Filter
Figure 4 Digital IF Band Pass Design Tool
You can use the filter design tool to design the optimal IF filter to match each pulse width
and application.
To show the filter, specify the impulse response and pass band. Use keyboard commands to
widen or narrow the filter and to automatically search for an optimal filter.
This display can also show the spectrum of the transmit burst pulse for quality control and
comparison with the filter.
Chapter 3 – Functional Description
27