Microcontroller homework for week 041. 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
3. The output code is
101011101101100
4. The value of the quantization
error between an input
voltage of 2.3V and quantized
voltage with the output code word equal to 01110101 using an 8 bit ADC with 5V
reference is
0.01484375V 5. 13 Bit ADC6. The circuit diagram:7. The run-up phase
takes 400 µs, the run-down phase takes
1 ms.
8. a) MAX1200 pipeline ADC - -85dB b) MAX1201 pipeline ADC - -85dBc) MAX1205 pipeline ADC - -84dB9. A) Flash ADC – expensive , high power consumption
B) SAR ADC – speed is limited,
needs anti-aliasing filter
C) Dual -Slope ADC – slow conversion, expensive external
components required
(high accuary components)
D) Sigma- Delta ADC – multibit ADC and multibit feedback DAC –
higher order
10. a) SARb) +- 0,4 LSB
c) 1,4 ms
d) 8,4 us11. Output voltage is 3,925V
12. Output voltage is 5,67V
13. The resolution of a 16bit DAC is 65536 bits
14. Gain error, offset error, resolution, monotonicity, accuary (relative)
15. A) 1,25B) 3,125
C) 1,87516. 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.
The
frequency should be about 30kHz, voltage 5V.
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