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 .
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.
Questions & Answers
What are the factors that affect demand for a commodity
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
When MP₁ becomes negative, TP start to decline.
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 •
Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
Kelo
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 •
Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
Ezea
ok
Shukri
how do you save a country economic situation when it's falling apart
Economic growth as an increase in the production and consumption of goods and services within an economy.but
Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
Shukri
production function means
Jabir
What do you think is more important to focus on when considering inequality ?
sir...I just want to ask one question... Define the term contract curve? if you are free please help me to find this answer 🙏
Asui
it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
Awais
thank you so much 👍 sir
Asui
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
Cornelius
Suppose a consumer consuming two commodities X and Y has
The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50.
A,Calculate quantities of x and y which maximize utility.
B,Calculate value of Lagrange multiplier.
C,Calculate quantities of X and Y consumed with a given price.
D,alculate optimum level of output .
the market for lemon has 10 potential consumers, each having an individual demand curve p=101-10Qi, where p is price in dollar's per cup and Qi is the number of cups demanded per week by the i th consumer.Find the market demand curve using algebra. Draw an individual demand curve and the market dema
suppose the production function is given by ( L, K)=L¼K¾.assuming capital is fixed find APL and MPL. consider the following short run production function:Q=6L²-0.4L³ a) find the value of L that maximizes output b)find the value of L that maximizes marginal product
Abdureman
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