Flashcards
DTEC S1 Flashcards
Cards in this deck (48)
- 1What is the Least Significant Bit (LSB)?Rightmost & lowest value binary bit
- 2What is a bit?A binary digit
- 3What is a Byte?group of 8 bits
- 4What is the Most Significant Bit (MSB)?Leftmost & honest value binary bit
- 5How many digits in the Decimal number system?10 (0-9)
- 6How many different Values can you have using a single Decimal Digit?10 (0-9)
- 7What is the result of extending Word Length by one Bit?The number of potential values in the Word doubles
- 8What is the result of decreasing Word Length by one Bit?The number of potential values in the Word halves
- 9As you count up in Binary, what always changes?Increments the LSB by 1
- 10How to calculate the relative value of the LSB placeholder in a Word?1 / how many bits
- 11What is Analogue expressed as and used for?Expressed as a continuum and used for signal transmission and storage
- 12What is Digital expressed as and used for?Expressed as discrete states and used for signal transmission and storage
- 13What is a Bus?electrical pathway used to transmit data
- 14What is Serial and Parallel TransmissionSerial = data transmitted 1 bit at a time
Parallel = data transmitted multiple bits at a time - 15How do you calculate Bandwidth?Bus width (Bytes) x Clock speed (MHz) = Peak Throughput (MB/Sec)
- 16What is a Clock?sets the reference tempo at which a digital system works
- 17What is the relevance of Clock Speed?higher clock speed allows for more information to be transmitted in a given time period
- 18What are the 2 steps to digitize an analogue signal?Sampling and Quantization
- 19What is the Nyquist Theorem?To properly recreate a waveform, the Sampling Frequency (Rate) needs to be at least twice the highest frequency present
- 20What is the Nyquist Frequency?The highest frequency that can be successfully sampled
- 21Sample Frequencydetermines how often an analogue signal is sampled
- 22What is Sample Period?Time elapsed between 2 samples
[1 second / sample frequency] - 23What is Quantization?Process of measuring the amplitude of an analogue signal and assigning a discrete value
- 24What is Dynamic Range?Ratio of the quietest signal to the loudest signal. Expressed in decibels
- 25With higher Bit Resolution, what happens to Quantization levels and Dynamic range?more quantization levels and greater dynamic range [# of bits x 6 = dynamic range]
- 26Each bit added to the word length does what to: Quantization levels, Dynamic Range and LSB?Doubles Quantization levels, Dynamic range increases by 6dB and reduces impact of LSB
- 27What is Quantization error?Difference between actual analogue signal and assigned digital quantization values (and is never more than 1/2 the LSB aka 1/2=0.5)
- 28What is Dither?Low level noise added to signal to raise the value of the lowest bits [to combat quantization error]
- 29How do you calculate Clock Speed?Clock speed = 1 / sample frequency
- 30Formula for Alias FrequencySample frequency - Signal frequency = Alias frequency
- 31What is Aliasing?Digitizing higher frequencies than the Nyquist frequency cause unwanted components (Alias Tones) to appear in audio signal
- 32What is an Anti-Aliasing Filter?An analogue Low Pass filter that prevents frequencies higher than the Nyquist frequency from entering the ADC and becoming digitized
- 33What is the Modulation system typically used for in Digital Audio?LPC Modulation
- 34What should the relationship be between the clocks in the ADC and DAC?They should be synchronized
- 35For efficient transmission and storage, a modulation system should transmit:1.Digital Audio data
2. Clocking Information - 36What is PLL?Phase Locked Loop: Device that analyses phase and timing of incoming signal to recover and regenerate the clock frequency
- 37What is Jitter?Time based errors in an audio signal that can lead to noise and distortion in reconstructed audio signal
- 38Talk about Interface JitterOccurs during transmission from one component to another. Caused by cable interference/long cable lengths. Can be audible in DAC stage. Does not affect signal storage.
- 39Talk about Sampling JitterOccurs during ADC & DAC process due to poor clocks/PLL designs. Jitter in DAC leads to incorrect playback. Jitter in ADC leads to incorrect capture of analogue signal
- 40Methods to reduce/control Jitter (4)1. more stable clocks
2. better PLL's
3. better/shorter cables
4. Master word clock - 41What is a Word Clock?a separate Reference Clock SIGNAL transmitted to digital devices for clock synchronization [only used in a digital system]
- 42What is a Master Clock?Typically a stand alone devices that generates the word clock. Other devices are set to reference the Master clock. Sends word clock to all devices in a digital system
- 43What is BMC?Biphase Mark Code: Encoding that keeps consistently reliant timing info despite presence or lack of regular transitions
- 44Quantization accuracy is dependent on?Word Length (Bit Resolution) of the digital system
- 45How should you combat Quantization Error when recording?Record at highest levels possible without clipping so there is more amplitude = more bits used (with less bits, the relative value of the LSB increases and QE increases)
- 46What is Digital Clipping Distortion?When input voltage exceeds highest available Quantization Level and record continuous 1's
- 47When is BMC encoding in the ADC done?Record Modulation stage
- 48Digital Audio Transmission specifications cover:1. Cabling
2. Data Protocol
3. Send/Receive Hardware