
VITA-49 Radio Transport Protocol
9. The
Over-range Indicator
shall be set to 1 if any data value in the packet has
reached full scale at the input of the digitizer.
10. The
Sample Loss Indicator
, when set to 1, shall indicate that data overflow
occurs
after
the current captured VRT packet,
not within
the packet. In other
words, the samples of the immediate packet following the current packet with the
sample loss indicator bit high are not continuous from those of the current packet.
lists the conditions in which an indicator would signal an abnormal state and the
suggested resolutions.
Table 35:
Conditions Causing Abnormal Indicator State and Suggested Resolution
Indicator
Name
Abnormal
State
Conditions
Suggested Resolution
Valid Data
0
1) One or more PLLs failed to
lock.
2) In HDR mode, the NB
ADC's filter has not settled.
1) Try to reset the frequency or
restart the WSA. If the condition
persists, contact ThinkRF's Support.
2) Discard the data packet and re-
acquire the data. This condition is
unlikely as the settle time is within
hundred of nanoseconds.
Reference
Lock
0
One or more PLLs failed to
lock.
Same as 1) above
Spectral
Inversion
1
Spectral inversion occurs
when the frequency of the
local oscillator exceeds that of
the RF input signal being
processed. At some signal
frequency ranges input to the
WSA5000, the IF output
spectrum is inverted.
Either swap each {I,Q} data point
when both {I,Q} components are
available or invert the output data
bins of the computed spectral
power. The latter suggestion is
recommended since SH and SHN
mode without the frequency shift
particularly have {I} only data.
Over-range
1
The over-range threshold is
the absolute full-scale of I or
Q data. For WB ADC, the
over-range threshold is at
Vpeak = 1.0 V; and for NB
ADC, Vpeak = 1.6 V.
- Enable the :ATTentuator if it is not
yet on.
- If :ATTentuator is already on,
reduce the input level or the gain
settings.
Sample Loss
1
This condition occurs only in
Stream mode when the
internal buffer is full.
Use a decimation value such that
the transfer rate matches that of the
capture rate.
Figure 10
: An Example Illustrating Uninverted and Inverted Spectrums
ThinkRF WSA5000 Wireless Signal Analyzer Programmer's Guide
41