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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.
Illustration 3.
As was said amplifier has unsymmetrical power supply. basis that was
set ratio resistors and R2. Unfortunately this one doesn’t include Pspice component
library.4: Schematic receiving amplifier with comparator
For the first simulation was set 0,1 amplitude VSIN source. Such operational amplifier has rail rail one
with desired voltage specification. This signal connected positive input of
operational amplifier.
For simulation received harmonic signal ultrasonic sensor VSIN source was
used. reach this by
connection positive input through resistor 1,65 branch. Another solution could connect receiver directly to
positive input and 1,65 branch. This requirements comply dual amplifier TS912
by STMicroelectronics [16]. widely using comparator which
works with 3,3 logic and therefore the output this comparator can connected
directly the digital input port evaluation board. VAMPL amplitude generating wave and was changing simulate different
conditions depending environment and whether within usage.
Common voltage level during testing was 0,5 peak peak.3. First adjustment by
adding component blue one curve.
The pink line comparator reference one.
The amplified output operational amplifier connected positive input of
the comparator LM339 STMicroelectronics. require add input
signal component 1,65 shift into working range. received 0,5 peak peak,
output signal would 2,85 V. Its positive peak reach 2,2 V. Course negative input can seen orange coloured curve.3 Amplification received signal and comparator
For amplification received signal was aim use operational amplifier which permit
us supply 3,3 and ground. Values and feedback resistor ensure
multiple 5,7 input signal the output.
The output operational amplifier cyan blue curve.
16
. when output amplifier reach 2,08 set
on reference, output comparator coloured yellow will positive voltage level. Another rail rail low voltage amplifier which can found there TLV2262
by and was chosen for simulation. received signal
has 0,2 peak peak image above curve with green colour. keep component
hear capacitor takes places
