Baron Services DSSR-250C TTY Nonvolatile Setups

RVP8 User’s Manual
October 2005

TTY Nonvolatile Setups

3. TTY Nonvolatile Setups

The RVP8 provides an interactive setup menu that can be accessed either from a serial TTY, or
from the host computer interface. Most of the RVP8’s operating parameters can be viewed and
modified with this menu, and the settings can be saved in non-volatile RAM so that they take
effect immediately on start-up. This permits custom trigger patterns, pulsewidth control,
matched FIR filter specs, PRF, etc., to be configured by the user in the field.

The TTY menu also gives access to a collection of graphical setup and monitoring procedures
that use an ordinary oscilloscope as a synthesized visual display. The burst pulse and receiver
waveforms can be examined in detail (both in the time and frequency domain) and the digital
FIR filter can be designed interactively to match the characteristics of the transmitted pulse.

3.1 Overview of Setup Procedures

This section describes basic operations within the setup menus such as making TTY connections,
entering and exiting the menus, and saving and restoring the configurations.

The setup TTY menu can be accessed by executing the following command:

$dspx

You will then be prompted by the following:

$dspx
Digital Signal Processor ’Chat’
Checking for code upgrades...Okay
(Type ^C to exit Chat Mode)

The interactive setup menu is invoked by pressing the Escape key on the TTY. If that key can
not be found on the keyboard, you can sometimes use Control “[” to generate the ESC code.
The RVP8 then responds with the following banner and command prompt.

SIGMET Incorporated, USA
RVP8 Digital IF Signal Processor V3.9(Pol) IRIS 8.03.6
––––––––––––––––––––––––––––––––––––––––––––––––––––––
RVP8>

The banner identifies the RVP8 product, and displays the RVP8 software version (e.g., V3.9)
and IRIS software version (e.g., IRIS 8.03.6). This information is important whenever RVP8
support is required, and it is also repeated in the printout of the “V” command (See below).

The “Q” command is used to exit from the menus and to reload the RVP8 with the (possibly
changed) set of current values. It is important to quit from the menus before attempting to
resume normal RVP8 operation. Portions of the RVP8 command interpreter remain running
while the menus are active (so that the TTYOP command works properly), but the processor as a
whole will not function until the menus are exited.

From the command prompt, typing “help” or “?” gives the following list of available
commands.

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Command List:
F: Use Factory Defaults
S: Save Current Settings
R: Restore Saved Settings
M: Modify/View Current Settings
Mb – Burst Pulse and AFC
Mc – Overall Configuration
Mf – Clutter Filters
Mp – Processing Options
Mt<n> – Trigger/Timing <for PW n>
Mz – Transmissions and Modulations
M+ – Debug Options
P: Plot with Oscilloscope
Pb – Burst Pulse Timing
Ps – Burst Spectra and AFC
Pr – Receiver Waveforms
P+ – Visual Test Pattern
V: View Card and System Status
?: Print all Menu Commands (this list)

?? – Print all Current Setup Settings
*: Sample Receiver Noise Levels
@: Display/Change the Current Major Mode
~: Swap Burst/IF Inputs on IFD
Q: Quit

TTY Nonvolatile Setups

3.1.1 Factory, Saved, and Current Settings

The current settings are the collection of setup values with which the RVP8 is presently
operating; the saved settings are the collection of values stored in non-volatile RAM. The saved
settings are restored (made current) each time the RVP8 starts. The “ S” command saves the
current settings into the non-volatile RAM, and the “R” command restores those non-volatile
values so that they become the current settings. The “F” command initializes the current settings
with factory default values. Thus, “F” followed by “S” saves factory defaults in non-volatile
RAM, so that the RVP8 powers up in its original configuration as shipped.

The RVP8 retains all of its saved settings when new software releases are installed; the new
version of code will automatically use all of the previous saved values. However, if the RVP8
detects that the new release requires a setup parameter that did not exist in the previous release,
then a factory default value will automatically be filled in for that parameter. A warning is
printed whenever this occurs (See also, Section 3.1.2).

There is also support for intermediate minor releases of RVP8 code. Each software release has a
major version number (the one that it always had), plus a minor version number for intermediate
”unofficial” releases. The minor number starts from zero at the time of each ”official” release,
and then increments until the next ”official” release. The RVP8 includes the minor release
number (if it is not zero) in the printout of the ”V” command. Likewise, the minor release

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number of the code that was last saved in the nonvolatile RAM is also shown. This is an
improvement over having to check the date of the code to determine which minor release was
running.

Note that the RVP8 does not actually begin using the current settings until after the “ Q”
command is entered, so that the processor exits the TTY setup mode and returns to normal
operation.

3.1.2 V — View Card and System Status

The “V” command displays internal diagnostics. This information is for inspection only, and
can not be changed from the TTY. The view listing begins with the banner:

Configuration and Internal Status
–––––––––––––––––––––––––––

and then prints the following lines:

RVP8 Digital IF Signal Processor V3.10(Pol) IRIS–8.04

This line shows the revision level of the RVP8 software, the IRIS version.

Settings were last saved using V3.10

This line tells which version of RVP8 code was the last to write into the non-volatile
RAM. It is printed only if that last version was different from the version that is
currently running. The information is included so that a “smart upgrade” can often
be done, i.e., values that did not exist in the prior release can be filled in with a guess
that is better than merely taking the factory default.

RVP8 started at: 13:07:33 3 NOV 2003
Current time is: 13:14:03 3 NOV 2003

These lines provide information about when the RVP8 was started, the current system
time, and implicitly, the uptime.

CPU–Type: Pentium(R) III

This line displays processor information.

IPP–Library: ippsa6 v2.0 gold SP1 2.0.6.39

This line displays information about the Intel libraries used for RVP8 processing.

Physical hardware inventory:
Found PCI Card RVP8/Rx – Rev.A Serial:1628 Code:14
(/dev/rda/rvp8rx–1)
Found PCI Card RVP8/Tx – Rev.B Serial:1887 Code:9
(/dev/rda/rvp8tx–0)
Found PCI Card I/O–62 – Rev.B Serial:1841 Code:19
(/dev/rda/io62–0)
\––> IO62CP Backpanel – Rev.B Serial:1822 Code:3

The physical hardware inventory provides information about the system hardware
being used by the RVP8. This list ONLY displays hardware that is being used, not all
hardware in the system (i.e., an RCP8 could be present in the same chasis, but the
RCP8 hardware would not be included in this list).

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Diagnostics: PASS

If errors were detected by the startup diagnostics then an error bitmask will be shown
on the first line. The word “PASS” indicates that no errors were detected.

Processes and Threads:
RVP8Proc–0 – PID:28503 Priority:10 Policy:RealTimeRR

The “Process and Threads” list displays RVP8 processes and their related priority.
All RVP8 processes/threads should be running under RealTimeRR policy to
guarantee adequate attention from the processors.

Shared library build dates:

This section provides RVP8 developers with information about code resources.

Front panel display:
+––––––––––––––––––––––+
| 0.00 AZ/EL 0.00 |
| FFT 100B 1000Hz x1 |
+––––––––––––––––––––––+

The front panel display mirrors the display on the front of the RVP8 chasis. This is
helpful if you are at a remote location using DspExport.

Tx/Clk:Okay TrigRAM is 99.0% free, TrigCount:378921

The Tx/Clk field displays information about the RVP8/Tx clock (if applicable).
TrigRAM provides resource information for those who are implementing custom
waveforms.

IFD:Okay Link: Delay = 0.541 usec, Jitter = 0.014 usec

This first section of this line summarizes the receiver status and Burst input signal
parameters. The status may show:

Okay RVP8/IFD and connecting cables are all working properly
DnErr Problem in DownLink connection from RVP8/IFD ––> RVP8
UpErr Problem in UpLink connection from RVP8 ––> RVP8/IFD
NoPLL RVP8/IFD PLL is not locked to external user-supplied clock reference
DiagSW RVP8/IFD test switches are not in their normal operating position

The section second describes the IFD link status. During startup the RVP8 measures
the round trip delay along 1) the uplink to the receiver module, 2) the pipeline delays
within the receiver module, 3) the downlink, and 4) pipeline delays in the data
decoding hardware. The time shown is accurate to within 14ns, and is used internally
to insure that the absolute calibration of trigger and burst pulse timing remains
unaffected by the distance between the main card and the receiver module. You may
freely splice any lengths of cable without affecting the calibrations; the delay time
will change, but the trigger and burst calibrations will remain constant.

The standard deviation of the measured delay is also shown. If the link to the IFD is
working properly this variation should be less than half the period of its acquisition
clock. Larger errors may indicate a problem in the cabling. A diagnostic error bit is
set if the error is greater than two acquisition clock periods.

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AFC:0.00% (Disabled), Burst Pwr:–48.6 dBm, Freq:30.000 MHz

AFC indicates the level and status of the AFC voltage at the RVP8/IFD module. The
number is the present output level in D-Units ranging from –100 to +100. The
shorter “%” symbol is used since percentage units correspond in a natural way to the
D-Units.

Burst Pwr indicates the mean power within the full window of burst samples. DC
offsets in the A/D converter do not affect the computation of the power, i.e., the value
shown truly represents the waveform’s (Signal+Noise) energy. Freq indicates the
mean frequency of the burst, derived from a 4

th

order correlation model.

For more information refer to Chapter 4.

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3.2 View/Modify Dialogs

The M menu may be used to view, and optionally to modify, all of the current settings. The
current value of each parameter is printed on the screen, and the TTY pauses for input at the end
of the line. Pressing Return advances to the next parameter, leaving the present one unchanged.
You may also type U to move back up in the list, and Q to exit from the list at any time.

Typing a numeric or YES/NO response (as appropriate to the parameter) changes the
parameter’s value, and displays the line again with the new value. All numbers are entered in
base ten, and may include a decimal point and minus sign. In some cases, several parameters are
displayed on one line, in which case, as many parameters are changed as there are new values
entered. In all cases, the numbers are checked to be within reasonable bounds, and an error
message (listing those bounds) is printed if the limits are exceeded. Note that changes to the
settings (generally) do not take effect until after the Q command is typed, at which point the
RVP8 exits the local TTY menu and resumes its normal processing operations.

The M menu provides access to a large number of configuration settings. As a result, all of the
M menu commands begin with the letter “M” and are followed by a lower case letter which
represents a subcategory, i.e., Mb (Burst Pulse and AFC), Mc (Overall Configuration), Mf
(Clutter Filters), Mp (Processing Options), Mt (Triggers and Timing), Mz (Transmissions and
Modulations), M+ (Debug Options). The ?? command by itself prints the entire set of
questions so that you can make a hard copy.

The M menu always works from the current parameter values, not from the saved values in
non-volatile RAM. If the host computer has modified some of the current values, then you will
see these changes as you skip through the setup list. However, typing S at that point would save
all of the current settings and would, perhaps, make many changes to the original non-volatile
settings. In general, to make an incremental change to the saved settings, first type R to restore
all of the saved values, then use the M menu to make the changes starting from that point, and S
to save the new values.

A listing of the parameters that can be viewed and modified with the M menu is detailed in the
following subsections. In each case, the line of text is shown exactly as it appears on the TTY
with the factory default settings. A definition of each parameter is given and, if applicable, the
lower and upper numeric bounds are shown.

3.2.1 Mc — Top Level Configuration

This set of commands configure general properties of the RVP8/IFD and RVP8 cards.

Acquisition clock: 35.9751 MHz

This is the frequency of the acqusition sampling clock in the IFD module. This will
generally be in the 72MHz range for the RVP8 CAT-5E IFD, and in the 36MHz range
for the legacy RVP7 IFD. If you are locking the IFD to an external reference, the
center frequency of the installed VCXO is entered (see section 2.2.12).

Limits: 33.33 to 80 MHz

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Live Angle Input – 0:None, 1:Sim, 2:TAGS, 3:S/D : 2

This setting is used to configure the input of live angles. In most situations, the
angles will be coming in from the RCP via TAGS. The S/D option provides direct
conversion of 3–wire synchro waveforms for the AZ and EL position angles. You
may directly hookup AZ/EL synchros to the 12–pin input connector on teh IO–62
standard backpanel when you choose S/D.

Primary RVP8/Rx PCI Card (–1:None) : 0

This setting configures which RVP8/Rx card will be used by the RVP8.

Primary RVP8/Tx PCI Card (–1:None) : –1

This setting configures which RVP8/Tx card will be used by the RVP8.

Primary I/0–62 PCI Card (–1:None : 0

Run I/0–62 external line powerup tests:NO

This setting configures which RVP8/Rx card will be used by the RVP8. The I/O–62
external line powerup tests are used for debugging the backpanel and should be
turned off during normal operation. When enabled, the backpanel receives a spread
of signals which could cause problems in an operational environment (.i.e. firing of
the transmitter).

TTY Nonvolatile Setups

Provide IRIS RPC network status server: NO

The default value is NO in order to reduce network security concerns. When
enabled, it opens up a network port.

PWINFO command enabled: No

The “Pulsewidth Information” user interface command can be disabled, thus further
protecting the radar against inappropriate combinations of pulsewidth and PRF. This
is a more safe setting in general, and is even more important when DPRT triggers are
being generated. It can also be useful when running user code that is not yet fully
debugged.

TRIGWF command enabled: NO

The “Trigger Waveform” user interface command can be disabled if you want to
prevent the host computer from overwriting the RVP8’s stored trigger specifications.
This is the default setting, based on the assumption that the built-in plotting
commands would be used to configure the triggers. Answering “YES” will allow
new waveforms to be loaded from the host computer.

Fundamental RVP8 Operating Mode: 0

The RVP8/IFD and RVP8/Rx cards can operate in one of several fundamental modes
for the acquisition of (I,Q) timeseries data. Please see Section 5.1.2 for details.

Important: The receiver mode is chosen in the “Mc” menu, but changes do not
take effect until they are saved and the RVP8 is restarted.

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3.2.2 Mp — Processing Options

Window- 0:User, 1:Rect, 2:Hamming, 3:Blackman : 0

Whenever power spectra are computed by the RVP8, the time series data are
multiplied by a (real) window prior to computation of the Fourier Transform. You
may use whichever window has been selected via SOPRM word #10, or force a
particular window to be used.

R2 Processing- 0:Never, 1:User, 2:Always : 1

Controls R0/R1 versus R0/R1/R2 processing. Selecting ”0” unconditionally disables
the R2 algorithms, regardless of what the host computer requests in the SOPRM
command. Likewise, selecting ”2” unconditionally enables R2 processing. These
choices allow the RVP8 to run one way or the other without having to rewrite the
user code. This is useful for compatibility with existing applications.

Clutter Microsuppression- 0:Never, 1:User, 2:Always : 1

Controls whether individual “cluttery” bins are rejected prior to being averaged in
range. Same interpretation of cases as for ”R2 Processing” above.

2D Final Speckle/Unfold – 0:Never, 1:User, 2:Always : 1

The Doppler parameter modes (PPP, DFT, etc) include an optional 3x3 interpolation
and speckle removal filter that is applied to the final output rays. This 2-dimensional
filter examines three adjacent range bins from three successive rays in order to assign
a value to the center point. Thus, for each output point, its eight neighboring bins in
range and time are available to the filter. Only the dBZ, dBT, Vel, and Width data are
candidates for this filtering step; all other parameters are processed using the normal
1-dimensional (three bins in range) speckle remover. See Section 5.3.3 for more
details.

Unfold Velocity (Vh–Vl) – 0:Never, 1:User, 2:Always : 0

This question allows you to choose whether the RVP8 will unfold velocities using a
simple (V

high

– V

) algorithm, rather than the standard algorithm described in

low

Section 5.6. Bit-11 of SOPPRM word #10 is the host computer’s interface to this
function when the “1:User” case is selected (See Section 6.3).

Note: This setup question is included for research customers only. The standard
unfolding algorithm should still be used in all operational systems because of its
lower variance. For this reason, the factory default value of this parameter is
“0:Never”.

Process w/ custom trigs – 0:Never, 1:User, 2:Always : 0

This question allows you to choose whether the RVP8 will attempt to run its standard
processing algorithms even when a custom trigger pattern has been selected via the
SETPWF command. Generally it does not make sense to do this, so the default
setting is “0:Never”. Bit-12 of OPPRM word #10 is the host computer’s interface to
this function when the “1:User” case is selected (See Section 6.3).

Use High–SNR 16–bit packed timeseries format: Yes

This parameter provides an additional 6dB of SNR. It can be disabled to provide
compatibility with legacy systems.

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Minimum freerunning ray holdoff: 100% of dwell

This parameter controls the rate at which the RVP8 processes free-running rays. This
prevents rays from being produced at the full CPU limit or I/O limit of the processor
(whichever was slower); which could result in highly overlapping data being output
at an unusably fast rate. Note that this behavior will only occur when running
without angle syncing, such as during IRIS Manual and RHI scans.

To make these free-running modes more useful, you may establish a minimum
holdoff between successive rays, expressed as a percentage of the number of pulses
contributing to each ray. Choosing 100% (the default) will produce rays whose input
data do not overlap at all, i.e., whose rate will be exactly the PRF divided by the
sample size. Choosing 0% will give the unregulated behavior in which no minimum
overlap is enforced and rays may be produced very quickly.

Limits: 0 to 100%

Linearized saturation headroom: 4.0 dB

The RVP8 uses a statistical saturation algorithm that estimates the real signal power
correctly even when the IF receiver is overdriven (i.e., for input power levels above
+4dBm). The algorithm works quite well in extending the headroom above the top
end of the A/D converter, although the accuracy decreases as the overdrive becomes
more severe. This parameter allows you to place an upper bound on the maximum
extrapolation that will ever be applied. Choosing 0dB will disable the algorithm
entirely.

TTY Nonvolatile Setups

Limits: 0 to 5dB

Apply amplitude correction based on Burst/COHO: YES
Time constant of mean amplitude estimator: 70 pulses

The RVP8 can perform pulse-to-pulse amplitude correction of the digital (I,Q) data
stream based on the amplitude of the Burst/COHO input. Please see Section 5.1.7 for
a complete discussion of this feature.

Limits: 10 to 500 pulses

IFD built–in noise dither source: –57.0dBm

This question will only appear if the processor is attached to a Rev.D RVP8/IFD that
includes an out-of-band noise generator to supply dither power for the A/D
converters. The available power levels are { Off, –57dBm, –37dBm, –32dBm,
–27dBm, –22dBm, –19dBm }. The closest available level to your typed-in value will
be used. You can observe the band-limited noise easily in the Pr plot to confirm its
amplitude and spectral properties.

For standard operation, we recommend running at –57dBm. The problem higher
levels of dither level is that, for certain choices of (I,Q) FIR filter, the stopband of the
filter may not give enough attenuation to preserve the RVP8/IFD’s inherent noise
level. For example, the factory default 1MHz bandwidth Hamming filter has a
stopband attenuation near DC of approximately 43dB. You can see this graphically at
the right edge of the Ps menu. The in-band contribution of dither power is therefore
approximately (–37dBm) – 43dB = –80dBm, which exceeds the A/D converter’s
1MHz bandwidth noise of –81.5dBm.

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IFD Wide Dynamic Range Parameters
Channel separation: 20.00 dB, 0.0 deg
Maximum deviation : 0.50 dB, 5.0 deg
Overlap/Interpolate interval: 30.00 dB

The Channel Separation and Overlap/Interpolate Interval should be determined
from the Pr printout described below. Sweep a SigGen across the shared power
region of the two channels to determine a representative channel separation, along
with the size of the overlap region at the top of the HiGain channel within which that
separation remains steady and constant, i.e., unaffected by eventually approaching the
noise floor of the LoGain channel.

The RVP8 continually measures and updates the complex channel separation during
normal operation. Ratios of echoes that fall within the overlap/interpolate interval
are averaged over several minutes, thereby tracking gain and phase variations that
occur with temperature changes and component aging. If the channel separation ever
exceeds the specified maximum deviation, the GI4S_IFDCHANERR bit (11) will be
set in GPARM Immediate Status Word #4.

TAG bits to invert AZ:0000 EL:0000
TAG scale factors AZ:1.0000 EL:1.0000
TAG offsets (degrees) AZ:0.00 EL:0.00

TTY Nonvolatile Setups

The incoming TAG input bits may be selectively inverted via each of the 16-bit
words. The values are displayed in Hex. Setting a bit will cause the corresponding
AZ (bits 0–15) or EL (bits 16–31) lines to be inverted. Note that the SOPRM
command also specifies TAG bits to invert. Both specifications are XOR’ed together
to yield the net inversion for each TAG line.

The overall operations are performed in the order listed. Incoming bits are first
inverted according to the two 16-bit XOR masks. This yields an unsigned 16-bit
integer value which is then multiplied by the signed scale factor. The result is
interpreted as a 16-bit binary angle (in the low sixteen bits), to which the offset angle
is finally added.

As an example, suppose that the elevation angle input to the RVP8 was in an
awkward form such as unsigned integer tenths of degrees, i.e., 0x0000 for zero
degrees, 0x000a for one degree, 0x0e06 for minus one degree, etc. If we apply a
scale factor of 65536/3600 = 18.2044 to these units, we will get 16-bit binary angles
in the standard format. If we further suppose that the input angle rotated
“backwards”, we could take care of this too using a multiplier of –18.2044.

Interference Filter – 0:None, Alg.1, Alg.2, Alg.3: 1
Threshold parameter C1: 10.00 dB
Threshold parameter C2: 12.00 dB

The RVP8 can optionally apply an interference filter to remove impulsive-type noise
from the demodulated (I,Q) data stream. See Section 5.1.5 for a complete description
of this family of algorithms.

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Provide WSR88D legacy BATCH major mode: YES
Maximum range to unfold: 600.0 km
Low–PRF bins range averaged on each side: 2
Overlay power – Refl:5.0dB Vel:8.0dB Width:12.0db
LowSamps = ( 0.00000 x HiSamps ) + 6.00 :
LowPRF = ( 0.00000 x HiPRF ) + 250.00 :

This is actually a fully general implementation of a Lo/Hi Surveillance/Doppler PRF unfolding
scheme that provides all of the legacy features as special cases. The parameters are defined as
follows:

S The maximum range to unfold is given in km. This allows you to set an upper bound on

how many Doppler trips will be unfolded according to the echoes seen in the surveillance
data.

S The surveillance data set uses very few pulses and therefore is somewhat noisy. You may

choose the number of bins that will be range averaged from both sides of these bins to
provide a lower variance power estimate. A value of zero means “No averaging”, a
value of one would average three points total, etc.

S The unfolding algorithm flags obscured range bins according to three different power

thresholds for reflectivity, velocity, and width, and outputs these bits in the DB_FLAGS
data parameter. Each of these thresholds is specified in deciBels.

S The fundamental RVP8 operating parameters (PRF, Sample Size, etc) all apply to the

high PRF portion of the BATCH trigger waveform. The low PRF rate and sample size
are derived from these high values using a slope and offset. In the example shown
above, the slopes are both zero, so that the surveillance data will be fixed at 6-pulses and
250-Hz. Making the slopes nonzero would cause the low-PRF parameters to vary
automatically if desired.

These setup parameters are accessible through the DSP driver using the new entry points
dspw_batchSetup() and dspw_batchSetup(). These use the custom opcode that is defined
separately by each major mode, so you may find customUserOpcode_batch() to be a useful
model for how to build such things.

Polarization Params – Filtered:YES NoiseCorrected:YES
PhiDP – Negate: NO , Offset:0.0 deg
KDP – Length: 5.00 km
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 question decides whether all polarization parameters will be computed from
filtered or unfiltered data, and whether noise correction will be applied to the power
measurements.

F

The second and third questions define the sign and offset corrections for

and the

DP

length scale for KDP.
The fourth and fifth questions control how the standard parameters (Total

Reflectivity, Corrected Reflectivity, Velocity, and Width) are computed in a multiple
polarization system. Answering YES to H-Xmt and/or V-Xmt means that data from

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