Microcontroller homework for week 04 1. SNR - Ratio of RMS signal to RMS SINAD - Ratio of the RMS signal amplitude to the mean value of the root-sum-square (RSS) ENOB - The effective number-of-bits and relates to SINAD THD - Ratio of the rms value of the fundamental signal to the mean value of the RSS of its harmonics. SFDR - Ratio of the RMS value of the signal to the RMS value of the worst spurious signal. Channels related to the inputs of the ADC can either be multiplexed or individually selected. Linearity relates to how a ADC follows a linear function. All ADCs are to a certain extend non-linearity. Temperature is measurement, which in optimal state for ADC-s, lets them function correctly. Power dissipation refers to the amount power dissipated when the ADC is operating. 2. The output code is 001111012 and the voltage of the LSB is 0,0195V ...
Nt. T= (voolutugevuse mistahes väärtus kordub iga 0,02 s ehk 20ms järel) 8. 9. Elektromagneetiline võnkumine on laengu, voolutugevuse ja pinge perioodiline muutumine. Kui elektriväli ja magnetväli samaaegselt perioodiliselt muutuvad nimetatakse seda elektromagnetvõnkumiseks ning seda tekitab võnkering. 10. Võnkering on kondensaatorit (C) ja induktiivpooli (L) sisaldav vooluring, kus tekitatakse elektromagnetvõnkumine. (kasut. raadiosagedusliku 30kHz-300MHz filtrina) Võnkeringis muundub kondensaatori energia perioodiliselt pooli magnetvälja energiaks ja vastupidi. 11. Thomsoni valem ütleb, et võnkeperiood on võrdeline ruutjuurega induktiivsusest ja mahtuvusest. Sellega saab arvutada perioodi või sagedust. T= 2 T[S]-periood L[H]- induktiivsus C[F]- elektrimahtuvus 12. Elektromagnetlaineks nim. ruumis lainena levivat elektromagnetvälja (elektrivälja+magnetväli)
following input combinations. (Assume VR=5V). a) S2S1S0=0102 1,25 b) S2S1S0=1012 3,125 c) S2S1S0=0112 1,875 Question 16 1. Draw the motor current and the motor voltage characteristic during the operation with a constant PWM signal of 50% duty cycle. 2. Recommend the suitable range of frequency for this PWM applied in microcontrollers. Analyze the advantages and disadvantages of PWM systems. The frequency should be about 30kHz, voltage 5V. The advantages of PWM systems: 1) Very high efficiency (not much heat produced) 2) Relatively cheap 3) Makes the motor run better The disadvantages of PWM systems: 1) PWM circuits are complicated 2) Sensitive to electromagnetics and could interfere with radio signals, cause vibration frequencies, which causes noise.
Nelinurksignaali korral spektrikomponendid avalduvad: u(t) = 4A/(sint + 1/3 sin3t + 1/5 sin5t ...) = 2f = 2/T 4.) Mõõtsime sagedusmoduleeritud (FM) signaali spektrit. Selleks kasutasime signaali allikana kõrgsagedusgeneraatorit HP8648B välise modulatsiooniga reziimis. - kandesagedus f = 180 MHz (HP8648B) 0 - moduleeriva harmoonilise sagedus F = 15kHz, u = 100mV (HP33250A) - modulatsiooni tüüp: väline (HP8648B) - Sagedusdeviatsioon f= 30kHz Mõõtsime kõigi spektrijoonte kõrgused ja sagedused markeri abil. Tulemuste põhjal koostasime tabeli. Arvutasime välja spektri teoreetilise kuju.LISA2 Tabel 2. Spektrijoonte kõrgused ja sagedused Mõõdetud spektrijoonte kõrgused ja sagedused: Järjekorra Spektritjoonte Spektrijoonte Spektrijoonte Spektrijoonte nr. sagedused f[MHz] teoreetilised amplituud U teoreetilised
The PWM switching frequency has to be much faster than what would affect the load on DC motors. 1. Draw the motor current and the motor voltage characteristic during the operation with a constant PWM signal of 50% duty cycle. 2. Recommend the suitable range of frequency for this PWM applied in microcontrollers. Analyze the advantages and disadvantages of PWM systems. The frequency should be about 30kHz, voltage 5V. The advantages of PWM systems: Very high efficiency (not much heat produced) Relatively cheap Makes the motor run smoother The disadvantages of PWM systems: PWM circuits are complicated Sensitive to electromagnetics and could interfere with radio signals, cause vibration frequencies, which cause noises.
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