Milltronics airanger XPL plus, Инструкция по эксплуатации, Страница: 83 / 114

7ML19981AN02 AiRanger XPL Plus – INSTRUCTION MANUAL Page 79
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Technical Reference
Transmit Pulse
The XPL Plus transmit pulse consists of one or more electrical "shot" pulses, which are
supplied to the scanning relays. The scanning relays are activated as required, to supply
the transmit pulse to the appropriate transducer connected to the XPL Plus terminals.
The transducer fires an acoustic "shot" for each electrical pulse supplied. After each shot
is fired, sufficient time is provided for
echo
(shot reflection) reception, before the next (if
applicable) shot is fired. After all shots of the transmit pulse are fired, the resultant
echoes are processed.
The transmit pulse shot number, frequency, duration, delay, and associated measurement
range are defined by parameters P803 and P840 to P852.
Echo Processing
Echo processing consists of echo enhancement, true echo selection, and selected echo
verification.
Echo Enhancement is achieved by
filtering
(removing noise, P821 and P822) and
reforming
(connecting fragmented echo peaks, P823) the
echo profile
(digitized signal
representing the echo signal received).
T
rue echo selection is achieved by establishing the criteria which a portion of the echo
profile must meet to be considered the
true echo
(echo reflected by the intended target).
Insignificant portions of the echo profile outside of the measurement range (Empty
Distance P006 + Range Extension P801), below the TVT Curve (P830 to P835), and less
than the Confidence Threshold (P804) and Short Shot Floor (P851) are automatically
disregarded.
The remaining portions of the Echo Profile are evaluated using the Algorithm(s) (P820)
and Short Shot Bias (P850) programmed. When a combination of Algorithms are used,
the portion of the Echo Profile providing the best averaged Echo Confidence (P805), is
selected as the true echo.
True echo verification is automatically achieved by comparing the position (relation in
time after transmit) of the "new" echo to the previously accepted echo position.
If the new echo is within the Echo Lock Window ( P713 ), the new echo is accepted and
displayed, and SAM-20 relays and AO-10 mA outputs are updated as restricted by the
Fuzz Filter ( P710 ) and Rate Parameters ( P700 to P703 ). If the new echo is outside of the
Echo Lock Window, the new echo is not accepted until
Echo Lock
( measurement
repeatability, P711 ) requirements are satisfied.