Electronic circuits II Example set of questions Łódź

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 1) Explain difference between the noise and the distortion.

2) Explain difference between the noise and the interference.

3) Explain why efficiency of a power amplifier is important?

4) Give the conditions that must be met in order to amplifier does not introduce linear distortions.

5) An amplifier Has gain of 60db. Express the gain in V/V.

6) Give difference between linear and nonlinear distortions.

7) The drawings below shows the waveforms and FFT of input and output signals of an amplifier. What kind of

distortion was introduced by the amplifier. Justify the answer.

8) Define PSRR (Power Supply Reejection Ratio).

9) Define CMRR (Common Mode Reejection Ratio).

10) Shortly characterize amplifier of class: A,B,C,D.

11) Shortly discuss principle of operations of class D amplifier(particularly mode of operation and type of load).

12) On the figure bellow an internal schematic of an power amplifier is show. Which class this amplifier

belongs. Justify the answer.

13) List sources of power loss in output stage of D class amplifier.

14) Give the basic difference between operation of the output stage between 2AB class and D class power

amplifier.

15) Define Dead Time.

16) List 6 causes of imperfection in Class D Power Amplifiers.

17) Which quality parameter depends on Dead Time in Class D Power Amplifiers.

18) Define a phenomenon of Power Supply Pumping in Class D Power Amplifiers.

19) What type of an output stage, in Class D Power Amplifiers, is affected by the phenomenon of Power Supply

Pumping.

20) Why Gate Drivers are needed in Class D Power Amplifiers.

21) Shortly explain operation of the Boot Strap circuit in a Gate Driver circuit for half bridge output stage.

0.000m 5.000m 10.00m 15.00m 20.00m 25.00m 30.00m

Time (s)

(V

)

-1.000

-0.750

-0.500

-0.250

0.000

0.250

0.500

0.750

1.000 vin

0.000m 5.000m 10.00m 15.00m 20.00m 25.00m 30.00m

Time (s)

(V

)

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

2.000

3.000

4.000

5.000 vout

FFT of "Transient Analysis" Chart, length = 128

0.000k 0.500k 1.000k 1.500k 2.000k

(Hz)

(V

)

0.000m

100.0m

200.0m

300.0m

400.0m

500.0m

600.0m

700.0m

800.0mvin

0.000k 0.500k 1.000k 1.500k 2.000k

(Hz)

(V

)

0.000

1.000

2.000

3.000

4.000

5.000

6.000 vout

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #...................................

22) On the figure bellow an internal schematic of an power amplifier is show. Which class this amplifier

belongs. Justify the answer.

23) Below one of power amplifier characteristics is show. Based on this characteristic give maximum output

power if the amplifier will be used in Police car for the PA (public Audio) speaker.

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 24) Below one of power amplifier characteristics is show. Based on this characteristic give maximum power

which can be dissipated in amplifier without heat sink if the ambient temperature will be 40 °C

25) A part of power amplifier data sheet is shown characteristics is show below. Based on this part give the

range of the output voltage swing.

26) Define rise time of the signal.

27) Explain relationship between rise time and high cutoff frequency of broadband amplifier.

28) To the input of the amplifier a test signal source is connected. Parameters of the amplifier are: gain = 60dB,

bandwidth = 0-10MHz. Parameters of the test signal, wave shape rectangular, pulse width 75% off voltage 0

V, on voltage 2,5mV. Sketch output signal of this amplifier if no nonlinear distortions are introduced

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 29) List impulse response distortions shown in the time plot of amplifiers output voltage. Mark those

distortions on the plot.

30) What will happen to the impulse response of the high-pass amplifier when we increase the lower limit

frequency?

31) In the figures below the frequency characteristics of the three amplifiers are show. Mark the characteristics

of the amplifier with the shortest delay in the impulse response.

0,000u 10,00u 20,00u 30,00u 40,00u 50,00u 60,00u 70,00u 80,00u

Time (s)

(V

)

-0,250

0,000

0,250

0,500

0,750

1,000

1,250

1,500

1,750

2,000

2,250 v_out

v_in

1,000 100,0 10,00k 1,000M 100,0M

Frequency (Hz)

0,000

50,00

100,0

150,0

200,0

250,0

300,0 vout_p1/vin_p1

vout_p2/vin_p2

vout_p3/vin_p3

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 32) The figure below shows a transistor amplifier in CE (Common Emitter) configuration. How does the R5

value affects the bandwidth of the amplifier?

33) The figure below shows the impulse response of two amplifiers built by means of the same integrated

circuit. Highlight a transient response of the faster amplifier. Explain the reason for the difference in speed

of these two amplifiers.

34) The figures below shows the frequency characteristic of two amplifier ICs. Highlight a characteristic of the

amplifier which should be applied for design an amplifier having shortest possible rise time.

35) Draw the amplitude characteristics of the NOTCH filter.

36) Draw the amplitude characteristics of the Comb filter.

37) Give difference between Butterworth and Czebyschew type 1 filter characteristic.

0 00

VCC

Rc

5k

RL

10k

R3

18k

R4

200k

VCC

0

Vs

FREQ = 1kHzVAMPL = 10mVVOFF = 0

AC = 10mV

C2

100uFC1

100uF

Rs

50

Q1

Q2N2222

R5

{Par}

V

V

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 38) Give difference between Butterworth and Bessel filter characteristic

39) What is the advantage of the filter of order 5 over the filter of order 1.

40) Draw a scheme the active low-pass filter.

41) For which signals the filter from the figure below can be regarded as a high-pass filter.

42) Explain the principle of operation of switched-capacitor resistor.

43) The figure below shows the frequency response of the digital filter. Give the minimum attenuation in the

stop band.

44) The figure below shows tipical application schematic for LCT1062 IC(Switched Capacitor Filter Explain the

functions of the highlighted items.

45) The figure below shows selected characteristics of switched-capacitor filter (MAX280). How to choose the

values of the resistance and capacitance of the input filter in order to have Butterworth type filter response

1,000 100,0 10,00k 1,000M 100,0M 10,00G

Frequency (Hz)

(V

)

-0,100 0,000 0,100 0,200 0,300 0,400 0,500 0,600 0,700 0,800 0,900 1,000 1,100

vout/vin

1,000 100,0 10,00k 1,000M 100,0M 10,00G

Frequency (Hz)

(D

eg)

-400,0

-325,0

-250,0

-175,0

-100,0

-25,00

50,00

125,0

200,0 PHASE(vout/vin)

AC Magnitude: 1

AC Phase: 0

Offset: 0

Amplitude: 1

Frequency: 1K

Phase: 0

V s

VSIN

G N D

1 K

R 1

Res1

1 u F

C 1

Cap

Vin

Vout

1 K

R 2

Res1

G N D

5

V_ccp

VSRC2

- 5

V_ccn

VSRC2

2

3

1

A

8

4

U1A

TL072ACD


.

46) A part of power amplifier data sheet is shown characteristics is show below. Based on this part give output

voltage range.

47) Draw a schematic of Any multiplier circuit.

48) Explain what it means that the multiplier circuit is a two quadrant one.

49) Briefly describe two ways of linearization of the two-quadrant multiplier circuit.

50) Describe the principle of operation of Gilbert type linearization circuit.

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 51) Explain the function performed by the resistors R3 and R4 in the schematic below.

52) Explain the principle of linearization used in the circuit of the figure below.

53) Draw the spectrum of the modulated signal for LSB modulation (single side band amplitude modulation

lower band broadcast) if the carrier is 20MHz modulating signal is shown below.

54) Draw a schematic any demodulator AM. Briefly explain its principle of operation.

55) Why after passing the diode the AM signal contains harmonics.

56) Shortly describe super diode circuit.

57) Sketch the time plot of AM (DSB-LC) modulated signal if modulation signal is a rectangle shaped signal with

fundamental frequency of 1kHz, carrier frequency is 10kHz modulation coefficient 50%. For a simplification

V2

V3

0 00

VCC

Q1 Q2

R1 R2

+

-

G1

GGAIN = 1

R3

5

21R4

5

21

V- V+

Q9Q10

V2

VCC

Q1 Q2

R2

Q3 Q4

R3

VCC

Q5 Q6

I11m

0

I2

1m

0

R4

1k

V3

Q7 Q8

0

I31m

I4

1m

0

R5

1k

R6

VCC

25kH 125kH


represent carrier as saw (triangle) shaped signal.

58) Draw a block diagram of a PLL circuit for multiplication of the reference generator frequency.

59) Give the minimum sampling frequency for the signal with the spectrum shown below:

60) Draw a block diagram and briefly explain the operating principle of successive approximation SAR ADC.

61) Draw a block diagram and briefly explain the operating principle of direct comparison FLASH ADC

62) Draw a block diagram and briefly explain the operating principle of double integration ADC

63) Draw a block diagram and briefly explain the operating principle of (delta sigma) ADC

64) Write down series of output values of ADC in binary code. Signal on the input is shown below. Parameters

of the converter are as follow: Voltage input range 0-4V, resolution 4 bits, sampling frequency 20 kHz. Mark

the quantized sample values on the graph.

65) Define /Explain Integral Nonlinearity (INL) Error.

66) Define /Explain Differential Nonlinearity (DNL) Error.

67) Describe Oversampling

68) Describe Multiplying DAC.

69) Explain principles of Ratiometric Measurement.

0

4V

0 200us 400us

Electronic circuits II Example set of questions Łódź 2013 First Name……………………….. Family Name………………………………… Index #................................... 70) Shortly describe element pointed by arrow In the AD7714. What it is what is it its function.

71) The picture below shows the internal construction of the converter MAX104. What kind of converter

constitutes this IC?

Electronic circuits II Example set of questions Łódź

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