final short answers

false frequencies that misrepresent a signal's true frequency content. happens when a continuous signal is sampled at a rate too low.

an analog signal can be digitized without aliasing error i.f.f the sampling rate is greater than or equal to twice the highest frequency component in a given signal.

when the sampling frequency is less than 2/3 the frequency.

indicates presence of a DC component or mean value in the time-domain signal.

system that processes information in real-time, it responds to events within a specific time.

cooperative and preemptive.

tasks take turns running, one yields to the other. not suitable for real-time programming.

one task can preempt another. guaranteed to run regardless of other tasks. good for real time programming. set of input pins, HIGH when not active. Interrupt pin goes to LOW, CPU stops current task and runs code attached to specific interrupt.

software routine that hardware invokes in response to an interrupt. calls special code to handle new event post interruption. Happens when interrupt pin goes LOW (active!)

fundamental frequency: lowest frequency of a periodic waveform. harmonics are integer multiples of fundamental frequnecies (x2, x3). subharmonics are integer fractions of fundamental frequencies (1/n, n= integer).

removes discontinuity from fourier transform. improves accuracy of frequency spectrum.

removes DC component - isolates oscillatory components of signal and improves clarity.

converts mechanical strain (stretching, compression) into measurable electrical resistance change. stretching increases electrical resistance, compression decreases resistance. converts changes in resistance to voltage signal.

no current into either input terminal of op-amp. voltage difference between the two input terminals is 0.

measures unknown electrical resistance by comparing it to known resistances in a balanced circuit. used for precise measurement of low resistances (useful for strain gauge)

the specific patterns or shapes in which the beam vibrates when excited at a particular natural frequency

damping force less than critical damping (oscillations are not fast enough to prevent the system from oscillating at all). system oscillates with a decreasing amplitude, gradually slowing down and coming to rest after many cycles.

returns to equilibrium as quickly as possible without oscillating or overshooting.

system returns to equilibrium without oscillating due to high damping. slowly moves towards equilibrium without overshoot. gradual approach to steady-state value without crossing it.

baseline reading or offset from a measuring instrument that needs to be zeroed out to get accurate results. handled by recording reading with no applied stimulus before starting measurements and subtracting this value from all subsequent measurements.

proportional gain Kp, derivative gain KD, and the target value the system is trying to achieve.

cannot eliminate steady-state error. stabilizes close to desired value but does not reach it exactly.

increasing proportional gain Kp.

increasing derivative gain Kd (acts like damping).

increase proportional gain Kp.

can make voltage and current larger. controls the direction and speed of current flow through a load by switching the polarity of the voltage.

the minimum gain required until the system starts to oscillate with a steady amplitude. utimate period is the period of oscillations observed at this value.

ability to eliminate or reduce steady-state error.

provides a correction that is directly proportional to the current error. pushes to correct large errors. works like a spring - exerts force proportional to the displacement. helps system moves towards setpoint.

reacts to rate of change of error. if error changes rapidly, slows down the response. like friction or damping. improves stability, reduces oscillations.

sums the error over time. builds up a correction until the error is eliminated. like tank filling with water, if tank isn't full it keeps adding water to correct. eliminates steady-state error.

IMU = inertial measurement unit. combines three sensors, accelerometer, gyroscope, magnetometer. each with 3 axis measuring linear, angular accel, and earth's magnetic field.

linear variable differential transformer. 2 coils and a core. electromechanical sensor that measures linear displacement of core when AC voltage applied. differential voltage indicates displacement.

pressure applied to the throat, causes a displacement. LVDT measures displacement and generates electrical signal proportional to displacement. relationship between displacement and pressure is calibrated, output signal used to directly calculate pressure.

a type of force sensor used to measure the amount of force applied to an object. converts mechanical force to an electrical signal.

device used to measure the elongation or strain of a material under stress. detects change in length. purpose is to quantify how much material stretches or compresses under load, determines material properties.

measures deformation (strain) caused by forces. knowing object's mass, can use newton's 2nd law to determine acceleration.

measures displacement by coverting the movement of its wiper along a resistive track into a change in resistance. this change in resistance alters Vout. Measuring Vout indicates position of wiper and therefore displacement.

temperature sensor made from two different metals joined at one end. the temp difference between the junctions generates a voltage which can be measured and converted into a temp reading.

the point at which two metal wires are not subjected to the temperature being measured and are instead maintained at a known temperature. temp difference between the reference and measurement junction creates the voltage output used to calc temp