PhSeq=0
Selects No Modulation. RVP900 outputs a constant default phase request as
defined in the Mz menu.
PhSeq=1
Selects a Random Phase sequence. This is also the default phase modulation that is
output following power-up. From the set of valid phase codes that are defined in the
Mz setup section, a random code is automatically chosen for each pulse. Each code
has an equal probability of being chosen each time, and the choice is independent of
any previous state. No XARGS words accompany this command.
PhSeq=2
Selects a User Defined sequence. If no XARGS have been supplied, RVP900
outputs the default idle phase that is defined in Mz. If XARGS are supplied, then they
are interpreted as a sequence of 16-bit binary angles.
RVP900 makes the best match between each desired angle and the closest realizable
angle that the phase modulation hardware can produce. The maximum length of the
sequence is 1024 pulses.
PhSeq=3
Selects the SZ(8/64) sequence.
This is a systematic code
1)
that separates and recovers first and second trip echoes in
Random Phase mode. It usually performs better than a truly random transmit
sequence, especially when the processing interval is fairly short (as little as 32-pulses).
With no XARGS, RVP900 automatically generates the phase sequence using the
closest realizable angles that the phase modulation hardware can produce. This is the
recommended way to invoke SZ(8/64) coding. You may also supply your own 32-
pulse angle sequence.
8.29 Set User IQ Bits (UIQBITS)
UIQBITS loads user-specified bits that are included with the pulse headers in the RVP900
TimeSeries API data stream.
The permanent Set/Clr bits are updated in the signal processor and retain their value
from the last time they were
defined. These bits are then repeated in all pulse headers. The
ONCE bits are transitory and appear in only one pulse header each time they are set.
A FIFO history of the permanent bits is maintained so that the bits can be associated with
the data being acquired right now as the UIQBITS opcode is executed. Each 16-bit
command arg
specifies bits to Set/Clr in successive bytes of the structure. This allows
user code to safely change some bits without aecting others.
The user bits from separate calls are never be collapsed into a single pulse header, even if
the header and bit times indicate that they could. This means that each UIQBITS opcode
always result in at least one pulse header being tagged with exactly that data. This is
generally what you want, since no other exact outcome could be guaranteed based on time-
of-arrival alone.
1) Sachidananda, M., D.S. Zrni, and R.J. Doviak, 1997: Signal Design and Processing Techniques for WSR–88D Ambiguity Resolution.
National Severe Storms Laboratory Report, Part 1, Norman, OK, 100 pp.
RVP900 User Guide M211322EN-J
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