FÖRELÄSNING V.3 TRUE/FALSE

Question 1

Signals are transferred in digital format among ECUs.

Answer 1

TRUE

Question 2

In general, by digitizing a signal, we lose information.

Answer 2

TRUE

Question 3

Sample frequency is an indicator of how much information we “lost” in term of time-resolution.

Answer 3

TRUE

Question 4

The number of bits of a digital signal inform us about its resolution and the quantization error

Answer 4

TRUE

Question 5

If we convert an analog signal to digital and use 10 bits, the digital signal can only represent 1024 values.

Answer 5

TRUE

Question 5

Using an extremely high sampling frequency and large bit resolution is the best solution to code digital signals because we lose the least amount of information.

Answer 5

FALSE

Question 6

In a normal distribution mean and median are the same.

Answer 6

TRUE

Question 6

Not all signals can be represented as a distribution

Answer 6

FALSE

Question 7

RMS and standard deviation have the same value for infinite signals with mean equal to zero.

Answer 7

TRUE

Question 8

By representing a signal as a distribution, we can visualize the probability for the signal to assume different values

Answer 8

TRUE

Question 8

In a normal distribution, most of the samples are within one standard deviation from the mean.

Answer 8

TRUE

Question 9

In a normal distribution the probability for a sample to be within one standard deviation is >76.32 %.

Answer 9

FALSE

Question 10

Digital information is transferred on the CAN bus (with analog signals).

Answer 10

TRUE

Question 11

ECU may communicate in different ways, a common one being via the CAN bus.

Answer 11

TRUE

Question 12

The (CAN) bus reduces the wiring needed to connect all sensors and ECUs.

Answer 12

TRUE

Question 13

The CAN bus is very robust.

Answer 13

TRUE

Question 14

It is possible to log and access the CAN bus in real time with a PC

Answer 14

TRUE

Question 15

Each frame has a different priority which is used to avoid frame collisions on the CAN bus.

Answer 15

TRUE

Question 16

The DBC files explain the priority of the different ECUs

Answer 16

FALSE

Question 17

A moving average filter is more robust than a median filter

Answer 17

FALSE

Question 18

Digital filtering is implemented using mathematical functions.

Answer 18

TRUE

Question 19

A first-order low-pass filter is an exponentially weighted moving average filter.

Answer 19

TRUE

Question 20

A high-pass filter stops high-frequency noise

Answer 20

FALSE

Question 21

A first-order low pass filter introduces a delay and this delay is larger the higher the frequency is.

Answer 21

TRUE

Question 22

The cut-off frequency of a low-pass filter gives an indication of which frequencies we may expect to pass or not pass through that filter

Answer 22

TRUE

Question 23

If a frequency f is attenuated by 60 dB by a filter it means that on the output we will only see only one millionth of the amplitude of f

Answer 23

TRUE

Question 24

A Kalman filter is an algorithm for optimal state estimation for linear systems in which controls and
measures are affected by gaussian noise

Answer 24

TRUE

Question 25

It is sufficient one single measure (either a control or an output to implement Kalman filtering)

Answer 25

FALSE

Question 26

Kalman filtering is used for sensor fusion in active safety systems.

Answer 26

TRUE

Question 27

Kalman filters work in two steps, prediction and correction

Answer 27

TRUE

Question 28

Kalman filters make the best out of the known information by determining which information we should trust the most (at each loop) to estimate our state

Answer 28

TRUE

Question 29

Unscented KF and extended KF provide an alternative to Kalman filter when the error is not gaussian.

Answer 29

FALSE

Question 29

Particle filters are very general, they do not require for a system to be linear nor for the error to be gaussian
distributed, but they are very computationally demanding.

Answer 29

TRUE