FÖRELÄSNING V.3 TRUE/FALSE Flashcards

1
Q

Signals are transferred in digital format among ECUs.

A

TRUE

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2
Q

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

A

TRUE

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3
Q

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

A

TRUE

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4
Q

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

A

TRUE

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5
Q

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

A

TRUE

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5
Q

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.

A

FALSE

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6
Q

In a normal distribution mean and median are the same.

A

TRUE

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6
Q

Not all signals can be represented as a distribution

A

FALSE

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7
Q

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

A

TRUE

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8
Q

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

A

TRUE

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8
Q

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

A

TRUE

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9
Q

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

A

FALSE

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10
Q

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

A

TRUE

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11
Q

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

A

TRUE

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12
Q

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

A

TRUE

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13
Q

The CAN bus is very robust.

14
Q

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

15
Q

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

16
Q

The DBC files explain the priority of the different ECUs

17
Q

A moving average filter is more robust than a median filter

18
Q

Digital filtering is implemented using mathematical functions.

19
Q

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

20
Q

A high-pass filter stops high-frequency noise

21
Q

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

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
TRUE
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
TRUE
24
A Kalman filter is an algorithm for optimal state estimation for linear systems in which controls and measures are affected by gaussian noise
TRUE
25
It is sufficient one single measure (either a control or an output to implement Kalman filtering)
FALSE
26
Kalman filtering is used for sensor fusion in active safety systems.
TRUE
27
Kalman filters work in two steps, prediction and correction
TRUE
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
TRUE
29
Unscented KF and extended KF provide an alternative to Kalman filter when the error is not gaussian.
FALSE
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.
TRUE