ATMS 360
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Theory of Operation
A theory of operation is a description of how a device or system should work.
It should be included in documentation, especially repair and maintenance documentation.
It aids troubleshooting by helping to provide the troubleshooter with a mental model that will aid him or her in diagnosing the problem.

Coded or programmed instructions that make the computer do work such as Microsoft Word, Firefox, and Excel. The applications talk to the Windowing Environment which in turn talks to the Operating System that is being run on a computer. (Source: Louis, Sushil. CS 135 Lecture)

Mechanical, magnetic, electronic, and electrical components that make up a computer system whether it be for personal use or use in other equipments.
(Source: Louis, Sushil. CS 135 Lecture)

Transducer  - A device which converts a physical quantity into an electrical signal (
A device for converting energy from one form to another. For example, a thermocouple transduces heat energy into electrical energy.
(Source: AMS Glossary, (A loudspeaker is a transducer that transforms electrical signals into sound energy.)

To standardize (as a measuring instrument) by determining the deviation from a standard so as to ascertain the proper correction factors. (Merriam Webster Online)

Dynamic Range
(specific definition with sound in mind). The ratio of the strongest to the weakest sound intensity that can be transmitted or reproduced by an audio or broadcasting system. (Merriam Webster Online)
In metrology, such as when performed in support of science, engineering or
manufacturing objectives, “dynamic range” refers to the range of values that can be measured by a
sensor or metrology instrument. Often this dynamic range of measurement is limited at one end of
the range by saturation of a sensing signal sensor or by physical limits that exist on the motion or
other response capability of a mechanical indicator. The other end of the dynamic range of
measurement is often limited by one or more sources of random noise or uncertainty in signal levels
that may be described as the defining the sensitivity of the sensor or metrology device. When digital
sensors or sensor signal converters are a component of the sensor or metrology device, the dynamic
range of measurement will be also related to the number of binary digits (“bits”) into which any
analog measurement quantities are converted to create digital numeric values. For example, a 12-bit
digital sensor or converter can only provide a dynamic range in which the ratio of the maximum
measured value to the minimum measured value is limited to 4096-to-1. (Source: Wikipedia)

The ability to respond to physical stimuli or to register small physical amounts or
differences. (Source: WordNet)

Resolution: 1. The degree to which nearly equal values of a quantity can be discriminated. 2. The smallest measurable change in a quantity. 3. The least value of a measured quantity that can be distinguished. 4. A formal inference rule permitting computer programs to reason logically. 5. The ability of an optical system to render visible separate parts of an object or to distinguish between different sources of light.
(Source: AMS Glossary,
The resolution of a sensor is the smallest change it can detect in the quantity that it is
measuring. Often in a digital display, the least significant digit will fluctuate, indicating that changes
of that magnitude are only just resolved. The resolution is related to the precision with which the measurement is made. For example, a scanning probe (a fine tip near a surface collects an electron tunnelling current) can resolve atoms and molecules. (Source: Wikipedia)

The extent to which results of a calculation or the readings of an instrument approach the true values of the calculated or measured quantities.
(Source: AMS Glossary,

The quality of being exactly defined.
(Source: AMS Glossary,

Time Constant
Also called lag coefficient. Generally, the time required for an instrument to indicate a given percentage of the final reading resulting from an input signal.
(Source: AMS Glossary,

(physics) The time required for a physical quantity to rise from zero to 1-1/e (that is, 63.2%) of its final steady value when it varies with time t as 1 - e-kt. The time required for a physical quantity to fall to 1/e (that is, 36.8%) of its initial value when it varies with time t as e-kt. Generally, the time required for an instrument to indicate a given percentage of the final reading resulting from an input signal. Also known as lag coefficient.

A change in an instrument's reading or set point value over extended periods due to factors such as time, line voltage, or ambient temperature effects.
Drift is an indication of the loss of perfect repeatability or reproduction of a measured value by an instrument. ---- (Own opinion)

Drift may be classified into three types: (A.K. Sawhney)

      Drift is an undesirable quantity that is rarely apparent and is hard to compensate for. Thus, it needs to be carefully guarded against by continuous prevention, inspection and maintenance.


Allan Variance
The Allan variance, named after David W. Allan, is a measurement of stability in clocks and oscillators. It is also known as the two-sample variance. It is defined as one half of the time average of the squares of the differences between successive readings of the frequency deviation sampled over the sampling period. The Allan variance depends on the time period used between samples: therefore it is a function of the sample period, as well as the distribution being measured, and is displayed as a graph rather than a single number. A low Allan variance is a characteristic of a clock with good stability over the measured period. The same quantity is useful when looking at the drift in instruments.

These are the items to consider when you are manufacturing and selling products.

- the amount of money needed to purchase something (

The amount (of money or goods or services) that is considered to be a fair equivalent for
something else. (Source: WordNet)

Market Share
- share of the total sales of all products within the product category in which the brand competes (

a. A grant made by a government that confers upon the creator of an invention the sole right to make, use, and sell that invention for a set period of time.
An example.

Component Cost
The decision as to whether or not to buy a component or service from an outside supplier is a complex one that most designers will be forced to make at some stage. It requires an understanding of the costs associated with making the components in-house and buying the components from a supplier. There may also be company considerations to consider when making the decision. For instance a company may be reluctant to buy components from a competitor even though the cost of manufacture in house may be more than the cost of buying from that competitor.

- the difference between invoice cost and selling price (

Service and Repair
an act of help or assistance to restore by replacing a part or putting together what is torn or broken (
Service includes the inspection of equipments to ensure proper functioning and is a part of its regular maintenance.
Many a times it is offered by the manufacturer.
Repair involves any fixing required to correct errors, restore, or mend damages reported during servicing.