Introduction Flashcards
what is a dicrete time signal? Draw one
Discrete signal is a signal with a fixed sampling rate that captures data as a discrete set of values
what is a sampling instant?
It is the rate at which the sampling happens - shammons theory states that it should be at least twice the highest frequency is the sample
two catagories of discrete time signals…
sampled data signals and digital signals
desribe a sampled data signall
displays a continous set of amplitude values
describe the characteristics of a digital signal
discrete and quantized set of amplitude values =- where the quantization error is eqaul to += half N where n = 2^N - the amount of bits basically
What does n denote
either the amount of samples (could be in a period or a cycle or just in total) or in terms of quantization the amount of bits available to represent the amplitude of an analogue signal
Discribe a typical analogue input to output DSP Scheme
Analogue input ->ADC -> DSP -> DAC -> Analogue output
Why is it important to have the right number of samples?
The output signal may be reduced in amplitude
Describe what a “sweep through” is and how it relates to freqencies and samples per a second
A sweep through goes through all of the frequencies in order to test different filters (low bandpass and high). The output (y[n]) will display amplitude peaks
What may changing the “multiplier coeffiences” do? Why would you do that?
more or less pronounced band pass effect
Describe and state the formula used to calculate the sampling frequency of a sample
called shammons formula and states the minum required sampling frequency to capture all the data of an analog signal call be calculated as 2f1 where f1 is equal to the highest frequency
What is the technical name for the maximum frequency
Nyquist frequency (f1)
What is the technical name for the minum sampling rate the capture the data?
folding frequency (2f1)
LTI is strictly….
It is a digital approach - avoiding any analogue circuity or techniques
describe unit step
This is where lots of unit impulses are held [u[n]
describe impulse
sigma [n] is where it is a spit of 1 discrete signal
describe ramp
r [n] where the signal ramps up
describe exponetial
exponetial can either be decaying (b <0) flat b = 0) or risingwhere b > 0) can be imaginary and real to represent sin and cosine
describe sin and cosine
where a component of the signal represents a sin and cos sine part
describe why simple functions are important in DSP
because they are easy to represent and can be combined together to produce complex signals
Name the main DSP module processor
LTI - linear time invarient
NAme the different operations tat an LTI processor can perform
Memory Addition/subtractions multiplication/division multiple numbers by there constants (multiplier coeffiences
Name the way of representing signal functions graphicalyl
Block diagrams
Give one basiic definition of a recursive function
it has a feedback loop
