Campionamento E Quantizzazione

The correct answer is "la frequenza di campionamento deve essere almeno il doppio della frequenza più alta presente nel segnale audio." This is known as the Nyquist-Shannon sampling theorem, which states that in order to accurately reconstruct a signal, the sampling frequency must be at least twice the highest frequency present in the signal. This is to ensure that all the information in the signal is captured and can be properly reconstructed.

A signal is considered digital when it proceeds in a discrete manner. This means that the signal is represented by a series of distinct values or levels, typically represented by binary digits (0s and 1s). Unlike analog signals, which are continuous and can take on any value within a range, digital signals have a finite number of possible values. This discrete nature of digital signals allows for more accurate and reliable transmission and processing of information.

A signal sampled at 44 KHz means that there are 44,000 cycles in one second. This is because the sampling rate of 44 KHz represents the number of times the signal is measured or sampled per second. In this case, each sample represents one cycle of the signal. Therefore, with a sampling rate of 44 KHz, there are 44,000 cycles in one second.

In the context of quantization, the unit of measurement is typically represented by bits. Bits are used to measure the level of quantization or the number of possible discrete values that can be represented. Each bit represents a binary value of either 0 or 1, allowing for a precise measurement and representation of data. Therefore, in quantization operations, the unit of measurement is typically expressed in bits.

To accurately digitize a signal, the sampling frequency must be at least twice the highest frequency component in the signal according to the Nyquist-Shannon sampling theorem. Since our hearing capacity reaches up to 20,000Hz, the sampling frequency should be higher than that to capture all the necessary information. Therefore, the correct answer is 44KHz, which is more than twice the maximum frequency of human hearing.

The correct answer is "Convertitore Analogico Digitalle" (Analog to Digital Converter). This device is missing in the audio chain. It is responsible for converting analog audio signals into digital format, which is essential for processing and storing audio data in digital devices such as computers and digital audio players. Without this converter, the audio chain would not be able to capture and process the analog audio signals effectively.

The correct answer is "segnale digitale" (digital signal). This is indicated by the use of the word "digitale" in the answer options. The question is asking what is represented in the figure, and based on the options provided, the figure is representing a digital signal.

Il fenomeno dell'aliasing è legato alla formazione di frequenze indesiderate a causa di una scelta errata della frequenza di campionamento. Quando un segnale analogico viene campionato a una frequenza troppo bassa, possono verificarsi problemi di aliasing, in cui le frequenze superiori alla metà della frequenza di campionamento vengono riprodotte in modo errato come frequenze più basse. Questo può causare distorsione e artefatti nel segnale digitale.

The error of quantization is caused by using a number of bits that is not suitable for the input signal. This means that the number of bits used to represent the signal is either too high or too low, leading to inaccuracies in the quantization process. If the number of bits is too high, it may result in unnecessary precision and a waste of resources. On the other hand, if the number of bits is too low, it can lead to a loss of information and a lower quality representation of the signal. Therefore, using an inadequate number of bits can cause the error of quantization.

The correct answer is "Filtro passabasso" because it is the missing device in the audio chain. A filtro passabasso, or low-pass filter, allows low-frequency signals to pass through while attenuating high-frequency signals. This filter is commonly used in audio systems to remove unwanted high-frequency noise or distortion, ensuring a cleaner and smoother sound output.

The correct answer is "convertitore digitale/analogico". The acronym DCA stands for Digital-to-Analog Converter, which is a device that converts digital signals into analog signals. This type of converter is commonly used in audio equipment, telecommunications, and other applications where digital signals need to be converted back to analog form for output or transmission.

La quantizzazione è legata all'ampiezza del segnale in ingresso. La quantizzazione è il processo di approssimazione di un segnale analogico a un segnale digitale, dove il segnale viene suddiviso in una serie di livelli discreti. L'ampiezza del segnale in ingresso determina il numero di livelli di quantizzazione che possono essere utilizzati per rappresentare il segnale. Un segnale con un'ampiezza più elevata richiederà un numero maggiore di livelli di quantizzazione per essere rappresentato accuratamente. Quindi, l'ampiezza del segnale in ingresso è un fattore determinante nella quantizzazione.

To avoid quantization error, it is necessary to apply the formula (6 x N) + 1.8. In this case, N represents the number of bits used for digitalization, which is 16. By plugging in the value of N into the formula, we get (6 x 16) + 1.8 = 97.8 dB. Therefore, the correct answer is 97.8 dB.

The correct answer is 44.100Hz e 16 bit. This is because the CD audio is digitized at a sampling rate of 44,100Hz, which means that 44,100 samples are taken per second to capture the audio. The bit depth is 16 bit, which indicates the number of bits used to represent each sample. A higher bit depth allows for a greater dynamic range and more accurate representation of the audio signal.

The correct answer is "ad evitare il fenomeno dell'aliasing" which translates to "to avoid the phenomenon of aliasing." Aliasing is a distortion that occurs when a signal is sampled or digitized at a frequency lower than its Nyquist frequency, resulting in false or inaccurate representations of the original signal. A low-pass filter is used to remove or attenuate high-frequency components of a signal, preventing aliasing from occurring and ensuring a more accurate representation of the signal.

Campionamento si riferisce al processo di misurazione o registrazione di un segnale analogico a intervalli regolari nel tempo. In questo contesto, "una discretizzazione sull'asse delle ascisse" significa che il campionamento avviene lungo l'asse orizzontale di un grafico, cioè nel tempo. Questo processo comporta la conversione del segnale analogico in un segnale digitale rappresentato da una serie di punti discreti sull'asse delle ascisse.