FÖRELÄSNING V.3 TRUE/FALSE Flashcards
Signals are transferred in digital format among ECUs.
TRUE
In general, by digitizing a signal, we lose information.
TRUE
Sample frequency is an indicator of how much information we “lost” in term of time-resolution.
TRUE
The number of bits of a digital signal inform us about its resolution and the quantization error
TRUE
If we convert an analog signal to digital and use 10 bits, the digital signal can only represent 1024 values.
TRUE
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.
FALSE
In a normal distribution mean and median are the same.
TRUE
Not all signals can be represented as a distribution
FALSE
RMS and standard deviation have the same value for infinite signals with mean equal to zero.
TRUE
By representing a signal as a distribution, we can visualize the probability for the signal to assume different values
TRUE
In a normal distribution, most of the samples are within one standard deviation from the mean.
TRUE
In a normal distribution the probability for a sample to be within one standard deviation is >76.32 %.
FALSE
Digital information is transferred on the CAN bus (with analog signals).
TRUE
ECU may communicate in different ways, a common one being via the CAN bus.
TRUE
The (CAN) bus reduces the wiring needed to connect all sensors and ECUs.
TRUE
The CAN bus is very robust.
TRUE
It is possible to log and access the CAN bus in real time with a PC
TRUE
Each frame has a different priority which is used to avoid frame collisions on the CAN bus.
TRUE
The DBC files explain the priority of the different ECUs
FALSE
A moving average filter is more robust than a median filter
FALSE
Digital filtering is implemented using mathematical functions.
TRUE
A first-order low-pass filter is an exponentially weighted moving average filter.
TRUE
A high-pass filter stops high-frequency noise
FALSE
A first-order low pass filter introduces a delay and this delay is larger the higher the frequency is.
TRUE
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
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
A Kalman filter is an algorithm for optimal state estimation for linear systems in which controls and
measures are affected by gaussian noise
TRUE
It is sufficient one single measure (either a control or an output to implement Kalman filtering)
FALSE
Kalman filtering is used for sensor fusion in active safety systems.
TRUE
Kalman filters work in two steps, prediction and correction
TRUE
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
Unscented KF and extended KF provide an alternative to Kalman filter when the error is not gaussian.
FALSE
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
