Instrumentation

Taking the mean and root mean squared (RMS) of an oscillating signal are equally valid ways of measuring signal amplitude

The degrees of freedom of a data set is equal to the number of data points

The sample variance represents a probable measure of the population variation

A ramp function is an example of a dynamic signal

Choose all of the examples of instrument error

A Fourier transform allows for signals to be reduced to combinations of sine and cosine waves with different

The DC component of a signal can always be removed by subtracting the signal mean

Systems involving inertial components must be modelled as

Choose all the common sources of calibration error

An even function is symmetric about the y-axis

Ground loops occur when a common mode voltage is produced by connecting two grounds that have the same reference voltage

A bridge circuit typically comprises four resistors to measure voltage changes

The _____________ filter maximizes flatness over the passband

The maximum voltage rang for an op amp is typically plus/minus

Ideal operational amplifiers have constant gain over all frequencies and infinite gain

Op amps can be used for:

These types of wiring will reduce noise transmission:

Ideal op amps have a finite gain

Filter roll-off is an unavoidable feature of real filters that is quantified by a slope

Potentiometers use a(n) _______________ to measure or control voltage levels

For an 8-bit system, bit 7 is the most significant bit (MSB)

Which are valid methods for reducing/eliminating signal 'leakage'

Digital filters are used for

Choose signal line practices will reduce noise and prevent ground loops:

If the sampling rate of a 10 Hz triangular wave is 10 samples per second, the apparent signal with be constant DC signal

The quantization (or quantization error) of an A-D converter is analogous to a devices resolution

Alias frequencies represent real signal frequencies

Folding diagrams are used to determine the apparent frequency of signal content that is:

Which sensor is used for calibration of other temperature sensors

An ice point reference junction can be produced using an actual ice bath or electronically

RTD and thermistors both use resistance changes with temperatures to sense temperature, but RTD's use conductors, whereas thermistors use semiconductors

Bimetallic thermometers are used for high precision temperature measurements

Which of the following are fundamental thermocouple law?

Match each device with the principle on which it is based

RTDs are optimal for measuring temperatures in rapidly changing environments

Match the effect with its definition

What are the three elements of a temperature scale?

Liquid-in-glass thermometers can have multi-degree errors if exposed to direct sunlight

The logarithmic decrement quantifies the decrease in amplitude of consecutive oscillatory peaks and can be used to find the damping ratio

Choose the features of a MEMS accelerometer

Boh piezoelectric and piezoresistive accelerometers are used in harsh environments

Match each feature with the appropriate accelerometer type

Piezoelectric accelerometers require relatively large amounts of power

Choose all possible direct accelerometer measurements

A system that is overdamped will oscillate with gradual decay over time

In general, the most common accelerometers use the movement of seismic or proof mass that is related the movement of an object of unknown acceleration

The natural frequency of an MSD system is dependent on:

Match the terms with their definitions

The relative displacement is the same as the difference between the seismic mass displacement and the housing displacement

DFT efficiency issues are addressed through use of the Fast Fourier Transform

The primary purpose of an accelerometer is to characterize the movement of the seismic or proof mass

Which of the following are potential applications of frequency analysis

Within the accelerometer, the inertia of the seismic mass is balanced by the damping and spring forces

Which of these are characteristics of a shock load

Choose all the variables that affect the damping ratio

Choose all statements that apply to the Discrete Fourier Transform (DFT)

Even aperiodic signals can be perfectly modeled using a Fourier time series

Regardless of design or application, the damping ratio should always be designed as 1, for critical damping

LVDTs and RVDTs are highly accurate and are therefore used for calibrating other devices and instruments

A stroboscope used to measure the rotational speed of an object will illuminate a single timing mark if the object is rotating at 900 rpm and the stroboscope is set to (choose all correct answers)

Encoders are commonly based on optical or magnetic signals

LVDTs produce output voltage that is proportional to the difference of secondary coil voltages

For period of 2s, an encoder with 20 blades that produces 400 pulses is rotating at:

LVDTs are powered by a DC source

A velocity can be found by integrating an acceleration signal even if the initial velocity

Choose all the characteristics of potentiometers used to measure displacement

LVDTs can only measure displacement in a single direction

For the angular velocity lab, Method 1 calculates speed by counting pulses during a period, whereas Method 2 uses the pulse period to calculate angular velocity

If total volume of a test specimen is conserved, it's Poisson ratio is:

Quarter-bridge configurations are limited to strain measurement in one axis on one side of a specimen

Strain gauges in the half-bridge configuration can be used to measure the same strain on opposite side or different strains on the same side of a specimen

The change in resistance of a strain gage can be affected by:

Rank the strain gauge configurations in order of sensitivity:

Which of these are effects of repeated cycling of newly mounted strain gauges?

Strain gauges resolution decreases with increasing length

Full-bridge configurations are the only ones that can compensate for transverse strains

Strain gauges are commonly used in test specimens plastic deformation regime

A type 2 quarter-bridge strain has the ability to compensate for temperature

The Mcleod gauge is used to calibrate pressure gauges using the combination of known tube cross sectional areas, known fluid properties, and Boyle's Law, which is:

Deadweight testers used for gauge calibration are highly accurate as they make use of the pressure being equal to a precisely measured mass (weight) divided by a precisely measured area

The difference between gage and absolute pressure is the reference pressure, which is usually the local atmospheric pressure

In general, transducers that incorporate piezoelectric crystals are best for static, not dynamic, signals.

Bourdon tube gages can be designed for various ranges and resolutions by varying the stiffness of the Bourdon tube

The deflection of diaphragm gauges are typically instrumented using single resistors or LVDTs

Inclining a manometer allows for higher resolution for increased accuracy by essentially 'stretching out' the distance a fluid is deflected for a given pressure difference

The 'torr' is a unit of pressure typically used in vacuum applications and is equal to:

A barometer is completely sealed device that measures atmospheric pressure

Pitot tubes indirectly measure velocity by finding dynamic pressure as the difference between which two pressures