Explains how digital systems such as the computer represent numbers. Covers the basics of boolean algebra and binary math.
Computer architecture
To understand digital signal processing systems, we must
understand a little about how computers compute. The moderndefinition of a
computer is an electronic
device that performs calculations on data, presenting theresults to humans or other computers in a variety of
(hopefully useful) ways.
Organization of a simple computer
Generic computer hardware organization.
The generic computer contains
input devices (keyboard, mouse, A/D (analog-to-digital) converter,
etc.), a
computational unit , and output
devices (monitors, printers, D/A converters). Thecomputational unit is the computer's heart, and usually
consists of a
central processing unit (CPU), a
memory , and an input/output
(I/O) interface. What I/O devices might be present on a givencomputer vary greatly.
A simple computer operates fundamentally in
discrete time. Computers are
clocked devices, in which
computational steps occur periodically according to ticksof a clock. This description belies clock speed: When you
say "I have a 1 GHz computer," you mean that your computertakes 1 nanosecond to perform each step. That is
incredibly fast! A "step" does not, unfortunately,necessarily mean a computation like an addition; computers
break such computations down into several stages, whichmeans that the clock speed need not express the
computational speed. Computational speed is expressed inunits of millions of instructions/second (Mips). Your 1
GHz computer (clock speed) may have a computational speedof 200 Mips.
Computers perform integer (discrete-valued)
computations. Computer calculations can be
numeric (obeying the laws of arithmetic), logical (obeyingthe laws of an algebra), or symbolic (obeying any law you
like).
An example of a symbolic
computation is sorting a list of names. Each computer instruction that performs an elementary
numeric calculation --- an addition, a multiplication, or adivision --- does so only for integers. The sum or product
of two integers is also an integer, but the quotient oftwo integers is likely to not be an integer. How does a
computer deal with numbers that have digits to the rightof the decimal point? This problem is addressed by using
the so-called
floating-point representation of real numbers. At its heart, however,
this representation relies on integer-valued computations.
Representing numbers
Focusing on numbers, all numbers can represented by the
positional notation system .
Alternative number representation systems
exist. For example, we could use stick figure counting orRoman numerals. These were useful in ancient times, but very
limiting when it comes to arithmetic calculations: ever triedto divide two Roman numerals? The
-ary positional
representation system uses the position of digits ranging from0 to
-1 to denote a number.
The quantity
is known as the
base of the number system.
Mathematically, positional systems represent the positiveinteger
as
and we succinctly express
in
base-
as
.
The number 25 in base 10 equals
,
so that the
digits representing this number are
,
, and all other
equal zero. This same number in
binary (base 2) equals 11001(
)and 19 in hexadecimal (base 16). Fractions between zero and
one are represented the same way.
All numbers can be represented by their
sign, integer and fractional parts.
Complex numbers can be thought of as two
real numbers that obey special rules to manipulate them.
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
from theory: distance [miles] = speed [mph] × time [hours]
info #1
speed_Dennis × 1.5 = speed_Wayne × 2
=> speed_Wayne = 0.75 × speed_Dennis (i)
info #2
speed_Dennis = speed_Wayne + 7 [mph] (ii)
use (i) in (ii) => [...]
speed_Dennis = 28 mph
speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5.
Substituting the first equation into the second:
W * 2 = (W + 7) * 1.5
W * 2 = W * 1.5 + 7 * 1.5
0.5 * W = 7 * 1.5
W = 7 * 3 or 21
W is 21
D = W + 7
D = 21 + 7
D = 28
Salma
Devon is 32 32 years older than his son, Milan. The sum of both their ages is 54 54. Using the variables d d and m m to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
however, may I ask you some questions about Algarba?
Amoon
hi
Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67.
Check:
Sales = 3542
Commission 12%=425.04
Pay = 500 + 425.04 = 925.04.
925.04 > 925.00
Munster
difference between rational and irrational numbers
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
