The module provides a review of the background concepts needed for the study of analog and digital communications: the Fourier transform, various definitions of bandwith, the Dirac delta, frequency-domain representation of sinusoids, frequency-domain plotting in Matlab, linear time invariant (LTI) systems, linear filtering, lowpass filters, and Matlab design of lowpass filters.
Fourier transform (ft)
Definition:
Properties:
Linearity:
.
Real-valued
.
“bandwidth”
Dirac delta (or “continuous impulse”)
An infinitely tall and thin waveform
with unit area :
that's often used to “kick” a system and see how it responds.
Key properties:
Sifting:
.
Time-domain impulse
has a flat spectrum:
Freq-domain impulse
corresponds to a DC waveform:
Frequency-domain representation of sinusoids
Notice from the sifting property that
Thus, Euler's equations
and the Fourier transform pair
imply that
Often we draw this as
Frequency domain via matlab
Fourier transform requires evaluation of an integral.
What do we do if we can't define/solve the integral?
Generate (rate-
) sampled signal in MATLAB.
Plot magnitude of Discrete Fourier Transform (DFT)
using
plottf.m (from course webpage).
Notice that
plottf.m only plots frequencies
.
Linear time-invariant (lti) systems
An LTI system can be described by either its “impulse response”
or its “frequency response”
.
Input/output relationships:
Time-domain: Convolution with impulse response
Freq-domain: Multiplication with freq response
Linear filtering
Freq-domain illustration of LPF, BPF, and HPF:
Lowpass filters
Ideal non-causal LPF (using
):
Ideal LPF with group-delay
t
o :
A causal linear-phase LPF with group-delay
t
o :
but MATLAB can give better causal linear-phase LPFs...
In MATLAB, generate
-sampled LPF impulse response via
h = firls(Lf, [0,fp,fs,1], [G,G,0,0])/Ts;
where...
The commands
firpm and
fir2 have the same interface,
but yield slightly different results (often worse for our apps).
In MATLAB, perform filtering on
-sampled signal
x via
y = Ts*filter(h,1,x); or
y = Ts*conv(h,x);
The routines
firls,firpm,fir2 generate
causal linear-phase filters with group delay
samples.
Thus, the filtered output
y will be delayed by
samples relative to
x .
Communication is effective because it allows individuals to share ideas, thoughts, and information with others.
effective communication can lead to improved outcomes in various settings, including personal relationships, business environments, and educational settings. By communicating effectively, individuals can negotiate effectively, solve problems collaboratively, and work towards common goals.
it starts up serve and return practice/assessments.it helps find voice talking therapy also assessments through relaxed conversation.
miss
Every time someone flushes a toilet in the apartment building, the person begins to jumb back automatically after hearing the flush, before the water temperature changes. Identify the types of learning, if it is classical conditioning identify the NS, UCS, CS and CR. If it is operant conditioning, identify the type of consequence positive reinforcement, negative reinforcement or punishment
nature is an hereditary factor while nurture is an environmental factor which constitute an individual personality. so if an individual's parent has a deviant behavior and was also brought up in an deviant environment, observation of the behavior and the inborn trait we make the individual deviant.
Samuel
I am taking this course because I am hoping that I could somehow learn more about my chosen field of interest and due to the fact that being a PsyD really ignites my passion as an individual the more I hope to learn about developing and literally explore the complexity of my critical thinking skills
hello. autism is a umbrella term. autistic kids have different disorder overlapping. for example. a kid may show symptoms of ADHD and also learning disabilities.
before treatment please make sure the kid doesn't have physical disabilities like hearing..vision..speech problem. sometimes these
Jharna
continue..
sometimes due to these physical problems..the diagnosis may be misdiagnosed.
treatment for autism.
well it depends on the severity.
since autistic kids have problems in communicating and adopting to the environment.. it's best to expose the child in situations where the child
Jharna
child interact with other kids under doc supervision.
play therapy.
speech therapy.
Engaging in different activities that activate most parts of the brain.. like drawing..painting. matching color board game.
string and beads game.
the more you interact with the child the more effective
Jharna
results you'll get..
please consult a therapist to know what suits best on your child.
and last as a parent. I know sometimes it's overwhelming to guide a special kid.
but trust the process and be strong and patient as a parent.
Jharna
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Source:
OpenStax, Introduction to analog and digital communications. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col10968/1.2
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