Bit streams through digital communications receivers.
The receiver interested in the transmitted bit stream must
perform two tasks when received waveform
begins.
It must determine when bit boundaries occur: The receiver
needs to
synchronize with the transmitted
signal. Because transmitter and receiver are designed inconcert, both use the same value for the bit interval
. Synchronization can occur
because the transmitter begins sending with a reference bitsequence, known as the
preamble . This
reference bit sequence is usually the alternating sequenceas shown in the
square wave example and in the
FSK
example . The receiver knows what the preamble bit
sequence is and uses it to determine when bit boundariesoccur. This procedure amounts to what in digital hardware
as
self-clocking signaling : The receiver of a
bit stream must derive the clock — when bit boundariesoccur — from its input signal. Because the receiver
usually does not determine which bit was sent untilsynchronization occurs, it does not know when during the
preamble it obtained synchronization. The transmittersignals the end of the preamble by switching to a second bit
sequence. The second preamble phase informs the receiverthat data bits are about to come and that the preamble is
almost over.
Once synchronized and data bits are transmitted, the
receiver must then determine every
seconds what bit was transmitted during the
previous bit interval. We focus on this aspect of thedigital receiver because this strategy is also used in
synchronization.
The receiver for digital communication is known as a
matched filter .
Optimal receiver structure
The optimal receiver structure for digital communication faced
with additive white noise channels is the depicted matchedfilter. This receiver, shown in
[link] ,
multiplies the received signal by each of the possible membersof the transmitter signal set, integrates the product over the
bit interval, and compares the results. Whichever path throughthe receiver yields the largest value corresponds to the
receiver's decision as to what bit was sent during the previousbit interval. For the next bit interval, the multiplication and
integration begins again, with the next bit decision made at theend of the bit interval. Mathematically, the received value of
, which we label
, is given by
You may not have seen the
notation before.
yields the maximum value of its argument with respect to the index
.
equals the value of the index that yields the maximum.Note that the precise numerical value of the integrator's output
does not matter; what does matter is its value relative to theother integrator's output.
Let's assume a perfect channel for the moment: The received
signal equals the transmitted one. If bit 0 were sent using thebaseband BPSK signal set, the integrator outputs would be
If bit 1 were sent,
Can you develop a receiver for BPSK signal sets that
requires only one multiplier-integrator combination?
In BPSK, the signals are negatives of each other:
. Consequently, the output of each
multiplier-integrator combination is the negative of theother. Choosing the largest therefore amounts to choosing
which one is positive. We only need to calculate one ofthese. If it is positive, we are done. If it is negative,
we choose the other signal.
Clearly, this receiver would always choose the bit correctly.
Channel attenuation would not affect this correctness; it wouldonly make the values smaller, but all that matters is which is
largest.
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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