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Kategorie: Diplomové, bakalářské práce |
Tento dokument chci!
Práce popisuje principy a problémy při realizaci ultrazvukového anemometru. Je popsán princip výpočtu rychlosti větru a následné korekce výpočtu. Pro realizaci jsou využity ultrazvukové sensory a microcontrolér ARM Cortex-M3. Práce se zabývá generováním PWM signálu, jeho analogovou filtrací, zesílením a odvysíláním. Na přijímací straně jeto nízkonapěťový zesilovač a komparátor. Vyvíjený kód je popsán pomocí vývojového diagramu.
The pink line comparator reference one. when output amplifier reach 2,08 set
on reference, output comparator coloured yellow will positive voltage level. widely using comparator which
works with 3,3 logic and therefore the output this comparator can connected
directly the digital input port evaluation board. received 0,5 peak peak,
output signal would 2,85 V. require add input
signal component 1,65 shift into working range. reach this by
connection positive input through resistor 1,65 branch. Values and feedback resistor ensure
multiple 5,7 input signal the output.4: Schematic receiving amplifier with comparator
For the first simulation was set 0,1 amplitude VSIN source.
For simulation received harmonic signal ultrasonic sensor VSIN source was
used.
The amplified output operational amplifier connected positive input of
the comparator LM339 STMicroelectronics. received signal
has 0,2 peak peak image above curve with green colour.3 Amplification received signal and comparator
For amplification received signal was aim use operational amplifier which permit
us supply 3,3 and ground. basis that was
set ratio resistors and R2.
As was said amplifier has unsymmetrical power supply.
16
. First adjustment by
adding component blue one curve. Another solution could connect receiver directly to
positive input and 1,65 branch. This requirements comply dual amplifier TS912
by STMicroelectronics [16]. This signal connected positive input of
operational amplifier.
Illustration 3. Another rail rail low voltage amplifier which can found there TLV2262
by and was chosen for simulation. keep component
hear capacitor takes places. VAMPL amplitude generating wave and was changing simulate different
conditions depending environment and whether within usage. Such operational amplifier has rail rail one
with desired voltage specification. Course negative input can seen orange coloured curve. Unfortunately this one doesn’t include Pspice component
library.
The output operational amplifier cyan blue curve.
Common voltage level during testing was 0,5 peak peak. Its positive peak reach 2,2 V.3
