EASA Part 66 : Digital Question3

Question Number. 35. A Digital to Analogue Converter has a resolution of 0.3 Volts. What will be the analogue output when the digital input is 10110. Option A. 6.6 Volts RMS. Option B. -6.6 Volts DC.G36. Option C. 6.6 Volts DC.

Correct Answer is. 6.6 Volts DC. Explanation. NIL.

Question Number. 29. Sample and hold is a technique used in. Option A. D to A conversion. Option B. Moving coil instruments. Option C. A to D conversion.

Correct Answer is. A to D conversion. Explanation. NIL.

Question Number. 27. What is the quickest method of analogue to digital conversion?. Option A. Voltage to frequency. Option B. Flash converter. Option C. Single ramp method.

Correct Answer is. Flash converter. Explanation. Digital Fundamentals by Thomas L Floyd.

Question Number. 3. What is serial to parallel and vice-versa called?. Option A. Switching. Option B. Multiplex/Demultiplex. Option C. Encoder/Decoder.

Correct Answer is. Multiplex/Demultiplex. Explanation. NIL.

Question Number. 31. What is 'Throughput Rate' for the A/D converter?. Option A. Number of complete digital words encoded in a specified unit of time. Option B. None of the above. Option C. Speed of variable resistor which senses the analogue signal.

Correct Answer is. Number of complete digital words encoded in a specified unit of time. Explanation. NIL.

Question Number. 32. What is the Resolution of A/D and D/A converters?. Option A. Resolution of the Instrument which displays the values. Option B. Number of discrete values that can be represented by the digital word. Option C. Rate at which data is converted.

Correct Answer is. Number of discrete values that can be represented by the digital word. Explanation. NIL.

Question Number. 17. What does 1 represent in an analogue system?. Option A. High frequency Option B. Switches closed, magnetised Option C. Switches open, unmagnetised

Correct Answer is. Switches closed, magnetised Explanation. NIL.

Question Number. 28. A charge balancing ADC uses. Option A. successive approximation logic circuit to control the output. Option B. a closed loop system to compare the analogue input to give the required digital output. Option C. a closed loop system to check the analogue input with the input sample.

Correct Answer is. a closed loop system to compare the analogue input to give the required digital output. Explanation. NIL.

Question Number. 4. A thyristor is a device which has. Option A. a positive temperature coefficient. Option B. a negative temperature coefficient. Option C. a temperature coefficient of zero.

Correct Answer is. a negative temperature coefficient. Explanation. NIL.

Question Number. 19. An analogue to digital converter where it counts up to binary state equal to the analogue input and then back down when this is reached is a. Option A. a ramp type converter. Option B. successive approximation counter. Option C. flash type converter.

Correct Answer is. a ramp type converter. Explanation. Digital Fundamentals T L Floyd page 790.

Question Number. 30. An analogue to digital converter (ADC) requires the following. Option A. a reference voltage, an input gate, an internal counter, a comparitor. Option B. a reference voltage, an input gate, a comparator. Option C. a reference voltage, an input gate, an internal counter.

Correct Answer is. a reference voltage, an input gate, a comparator. Explanation. NIL.

Question Number. 14. A digital to analogue converter that requires the output to range between 0v and -10v would have. Option A. a non-inverting amplifier in line with the output with a resistor to ground. Option B. an inverting amplifier in series with the output line. Option C. a non-inverting amplifier in parallel with the output line.

Correct Answer is. an inverting amplifier in series with the output line. Explanation. NIL.

Question Number. 6. A D to A converter is required to produce an output range of 0 to 10V. This can be achieved by. Option A. a non inverting op amp connected in series with output. Option B. an inverting op amp connected in series with output. Option C. a differentiator with a 100 Kilohm feedback resistor.

Correct Answer is. an inverting op amp connected in series with output. Explanation. NIL.

Question Number. 8. A given transducer provides a voltage which corresponds to true heading. This voltage can beconverted to 'bits' by using a. Option A. analogue to digital converter. Option B. digital to analogue converter. Option C. commutator.

Correct Answer is. analogue to digital converter. Explanation. NIL.

Question Number. 2. Within a computer controlled flight system, position feedback is converted from. Option A. position feedback to rate feedback. Option B. analogue to digital. Option C. digital to analogue.

Correct Answer is. analogue to digital. Explanation. NIL.

Question Number. 36. A number represented as a physical quantity, e.g. voltage or speed of rotation is. Option A. digital. Option B. maximum value. Option C. analogue.

Correct Answer is. analogue. Explanation. NIL.

Question Number. 5. Physical variables in quantitative forms, such as voltage or angular rotation of a shaft are. Option A. digital. Option B. analogue. Option C. binary.

Correct Answer is. analogue. Explanation. NIL.

Question Number. 1. If a signal has quantity in volts and physical position it is. Option A. digital. Option B. synchronous. Option C. analogue.

Correct Answer is. analogue. Explanation. This is the definition of an analogue signal.

Question Number. 18. Audio sounds recorded digitally. Option A. are superior quality and graeter bandwidth. Option B. are narrow bandwidth. Option C. are not as accurate due to clipping and input errors.

Correct Answer is. are superior quality and graeter bandwidth. Explanation. NIL.

Question Number. 33. Digital signals can be represented. Option A. only as a binary value. Option B. by a series of integers. Option C. by real numbers.

Correct Answer is. by a series of integers. Explanation. NIL.

Question Number. 20. Transistors are used in a current triggered D to A device to. Option A. switch off the inputs. Option B. switch on the input. Option C. change the state of the inputs.

Correct Answer is. change the state of the inputs. Explanation. NIL.

Question Number. 12. An encoder using Grey code. Option A. changes analogue to binary. Option B. changes digital to analogue. Option C. changes analogue to digital.

Correct Answer is. changes analogue to digital. Explanation. NIL.

Question Number. 22. Analogue logic 1 is. Option A. closed switch, Logic Q=0. Option B. closed circuit, Logic Q=1. Option C. open circuit.

Correct Answer is. closed circuit, Logic Q=1. Explanation. NIL.

Question Number. 26. In an R-2R ladder converter the values of resistors. Option A. do not need to be of precise values. Option B. only the first resistor need to be precise. Option C. are precise.

Correct Answer is. do not need to be of precise values. Explanation. NIL.

Question Number. 7. A D to A converter would use a precision amplifier to. Option A. compensate for the variation of the feedback resistor with temperature. Option B. ensure that the output voltages remain accurate. Option C. ensure that the input voltage remains accurate.

Correct Answer is. ensure that the output voltages remain accurate. Explanation. NIL.

Question Number. 24. A DAC uses a precision amplifier to. Option A. ensure the output voltages remain accurate. Option B. compensates for the variation of the feedback resistor due to temperature. Option C. ensure the input remains accurate.

Correct Answer is. ensure the output voltages remain accurate. Explanation. NIL.

Question Number. 25. A precision op-amp is used in a DAC to. Option A. compensate for temperature variation. Option B. give output at required level. Option C. make output between 0 - 5V.

Correct Answer is. give output at required level. Explanation. NIL.

Question Number. 21. Op amps generally used in ADCs and DACs are normally. Option A. high input impedance, high output impedance. Option B. high input impedance, low output impedance. Option C. low input impedance , how output impedance.

Correct Answer is. high input impedance, low output impedance. Explanation. NIL.

Question Number. 23. An ADC uses successive approximation to. Option A. increase speed. Option B. increase accuracy. Option C. increase resolution.

Correct Answer is. increase speed. Explanation. NIL.

Question Number. 9. An A to D converter uses successive approximation to. Option A. increase resolution. Option B. increase accuracy. Option C. increase speed.

Correct Answer is. increase speed. Explanation. NIL.

Question Number. 34. When testing EGT probe. Option A. it must be soaked and ambient temperature allowance taken into consideration. Option B. not necessarily soaked but ambient temperature must be taken into consideration. Option C. if its not soaked, a minimum temperature of 20 degrees C taken as OAT.

Correct Answer is. it must be soaked and ambient temperature allowance taken into consideration. Explanation. NIL.

Question Number. 11. The function of a commutator is to. Option A. convert from analogue to binary form. Option B. provide continuous availability of all parameters connected to the system. Option C. provide a sampling in sequence of a number of parameters.

Correct Answer is. provide a sampling in sequence of a number of parameters. Explanation. NIL.

Question Number. 15. In an analogue to digital converter, the input voltage. Option A. is switched by the digital input. Option B. is intermittent. Option C. stays on constantly.

Correct Answer is. stays on constantly. Explanation. NIL.

Question Number. 13. An analogue to digital converter is as accurate as. Option A. the frequency. Option B. the sampling rate. Option C. the amplitude.

Correct Answer is. the sampling rate. Explanation. NIL.

Question Number. 10. An R-2R D to A converter uses. Option A. two values of resistors whose precision is not important. Option B. two values of precision resistors. Option C. resistors whose values are logarithmic.

Correct Answer is. two values of resistors whose precision is not important. Explanation. NIL.

Question Number. 16. An R-2R Converter has values or resistance. Option A. whose relative precision are accurate. Option B. whose precision are not accurate. Option C. whose precision are accurate.

Correct Answer is. whose precision are not accurate. Explanation. NIL.