R1 vs. R2 Algorithms
The random phase algorithms for adaptive filtering and separation of trips relies on having
the best possible information about the weather's SNR and spectral width. Thus, the R2
Doppler algorithms are always used, regardless of the setting of the R1/R2 flag in the
operational parameters.
Random Phase and Dual PRF
The random phase processing works seamlessly with the dual PRF processing to provide
advanced range and velocity ambiguity resolution. Both the
first and second trip echoes can
be recovered and displayed to a maximum range of 2X the unambiguous range
corresponding to the high PRF.
For optimum performance, the 2D 3x3 speckle
filter should be used to smooth the second
trip seams that occur for each ray. In fact, this smoothing of the second trip seam makes the
dual PRF random phase mode work even better than the single PRF random phase.
For more information, see 7.9.1 Random Phase Second Trip Processing Algorithm
(page 227).
7.10 Signal Generator Algorithm Testing
The IF signal generator tests that can be used to verify the RVP900 processing algorithms.
Perform these tests after adding new algorithms or major modes to the processor.
You can use the test descriptions to debug your system, or better understand how they
work.
More Information
‣
Installation and Test Procedure Overview (page 339)
7.10.1
Linear Ramp of Velocity with Range
Suppose that a continuous-wave IF waveform has an instantaneous frequency f (t)in Hertz
(cycles/sec). Consider a range bin located at time
Ʈ
bin
within a set of pulses that are separated by Ʈ
s
= 1/PRF. The phase measured at that bin
on the n
th
pulse is the integral of the frequency within that pulse starting from range zero
(since RVP900 is phase-locked to range 0):
=
+
ⅆ
If we assume that the input frequency is a linear Frequency Modulation (FM) at the rate of M
cycles/sec/sec on top of a base frequency T
o
, then:
Chapter 7 – Processing Algorithms
231
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