User's Manual Part 2

Processing Algorithms (draft)
RVP8 User’s Manual
April 2003
5–50
5.7.11 Standard Moment Calculations (T, Z, V, W)
Overview
Standard moments are available for all four of the polarization cases. Since there can be up to
four different channels of time series input, there are several choices for computing the standard
moments. For example, in the STAR mode (Case 2), the standard moments can be computed
from:
S s
hh
samples
S s
vv
samples
S Average of the results from the s
hh
and s
vv
samples
The third case is handled by averaging the individual channel correlations, and then using the
average correlations in the standard moment processing. The averaging must take into account
the differential gain of the channels.
The selection of which method to use is made in setup. There are four questions posed in the mp
section:
T/Z/V/W computed from: H–Xmt:YES V–Xmt:YES
T/Z/V/W computed from: Co–Rcv:YES Cx–Rcv:NO
The first two questions are used to specify that given a choice between vertical and horizontal
transmit, which transmit polarization to use. Thus for the fixed H or V case where there is only
one transmit polarization, this question does not apply. The processor will simply use samples
for the polarization is transmitted.
The second two questions are used to specify that given a choice between using the co- or
cross-polar receivers which one shall be used. This question applies only to systems that can
measure LDR, i.e., fixed or alternating transmit, dual-channel receiver systems).
The tables in the sections below summarize the standard moment calculations for each of the
four modes and how to configure the four TTY setup responses. Note that these are the only
supported modes. Some combinations of responses are unsupported. For example, it is not
supported to answer both Co-Rcv: NO and Cx-Rcv: NO.
The top of each table identifies the transmitter/receiver case and what samples are available. The
notation HH signifies that the s
hh
samples are available. The tables use “–––” to indicate that
either a YES or NO response will cause the same result, i.e., the RVP does not care what
response is made. In cases where averaging is performed, the type of weighting used is indicated
(either GDR or XDR weighting).