Ch. 4 vocab

Amplitude

The height of a periodic wave which is a measure of its loudness.

Analog representation

Objects can take on any continuous value.

Arithmetic overflow

An attempt to represent an integer that exceeds the maximum allowable value.

ASCII

An acronym for the American Standard Code for Information Interchange; ASCII is an international standard for representing textual information in the majority of computers.

Binary number system

A base-2 positional numbering system.

Bit

A binary digit, 0 or 1.

Bit depth

The number of bits used to encode each sample during digitization.

Boolean expression

An expression that can evaluate only to true or false.

Boolean logic

A branch of mathematics which operates on the values true and false.

Byte

Eight bits.

Circuit

A collection of logic gates (1) that transforms a set of binary inputs into a set of binary outputs and (2) where the values of the outputs depend only on the current values of the inputs; more properly called a combinational circuit.

Circuit construction algorithm

An algorithm that allows us to go from a specification of what we wish to accomplish to a circuit that carries out those specifications.

Circuit optimization

The process of reducing the number of gates needed to implement a circuit.

Compression ratio

Measures how much a compression scheme has reduced the storage requirements of the data.

Control circuit

A circuit used to make decisions and control the flow of execution.

Data compression

The process of reducing the number of bits required to represent a sound or image.

Decoder

A control circuit that has N input lines numbered 0, 1, 2, …, N – 1 and 2N output lines numbered 0, 1, 2, 3, …, 2N – 1.

Digital representation

The values for a given object are drawn from a finite set, such as the letters {A, B, C, …, Z} or a subset of integer {0, 1, 2, 3, …, MAX}

Digitized

Converted from a continuous value to a single numeric value.

Fault-tolerant computing

[in Exercise 24] The ability to continue functioning even in the presence of the failure of one or more components.

Frequency

The total number of cycles per unit time measure in cycles/second, also called hertz.

Gate

An electronic device that operates on a collection of binary inputs to produce a binary output.

Gigabyte

One billion bytes.

Hardware design

The process of designing the low level components of a computer, including arithmetic and control circuits.

Logic design

Another term for hardware design as it uses the capabilities of Boolean logic to carry out the design process.

Lossless compression

No information is lost in the compress, and it is possible to reproduce exactly the original data.

Lossy compression

Compress data in a way that does not guarantee that all the information in the original data can be fully ad completely recreated.

Multiplexor

A control circuit that has 2N input lines and 1 output line.

Period

The time it takes for a single wave in a periodic wave function.

Positional numbering system

A numbering system in which each position of a number represents a value times the radix to a given power.

Raster graphics

A method for storing an image in which a sequence of picture elements is digitized and stored one row at a time, from left to right.

RGB encoding scheme

A method for encoding color that digitizes the contribution of the red, green, and blue components of each pixel.

Sampling

At fixed time intervals, the amplitude of a signal is measured and stored as an integer value; the wave is then represented in the computer in digital form as a sequence of sampled numerical amplitudes.

Sampling rate

The time interval between sampling points.

Scientific notation

A way to represent real numbers as a mantissa times a base to an exponential power.

Sequential circuit

Circuit that contains feedback loops in which the output of a gate is fed back as input to an earlier gate.

Sign/magnitude notation

A way to represent signed integer values in which one bit is used to represent the sign and the remaining bits are used to represent the magnitude.

Transistor

An electronic device that can be in an OFF state, which does not allow electricity to flow, or in an ON state, in which electricity can pass unimpeded; a transistor is a solid-state device that has no mechanical or moving parts.

Truth table

A table that contains columns labeled inputs that list the possible combinations of true/false values.

Two’s complement representation

A way to represent signed integer in which we count up from zero to represent positive values and we count down from zero to represent negative values.

Unicode

Uses a 16-bit representation for characters.