SD292 Glossary
Terms
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- Offset Binary Coding
- resistor and voltage attached to D/A converter causing it to drop the voltage range down by one significant bit 0000 ---> 1000
- Integral Linearity Error
- when theres a hump in the graph
- Principle of Transduction
- convert a change in physical properties to electrical energy
- Roll-Off
- rate of decay of gain past the cut off frequency; for a first order filter = -20dB; second order = -40 dB; Ultimate RollOff = one decade above frequency high = below
- Kirchoff's Current Law
- sum of currents entering a node = sum of currents leaving; nodal analysis
- Loading Effects
- distortion caused by circuit connected to the output
- Thevenin Equivalent Circuit
- network of components can be reduced down to one voltage source to one resistor --> impedances, can be capacitors and inductors <-- in series
- Independent Voltage Source
- a voltage source that is removed from the load, so it will have no loading effect, independing of circuit elements;maintains constant voltage/current across its terminals
- Monostable
- one shot, uses positive feedback to maintain one stable state, until perturbed and changes states for temporary amount of time
- Equivalent Power Sources
- to convert between voltage and current sources
- Current Divider
- in parallel, method of determining current across a series of parallel resistors
- Frequency Response
- the magnitude and phase graph of a instrument (filter/opamp) of a circuit as it varies across different frequencies; i.e. Bode plot
- Passive Circuit Component
- does not produce its own power; draws or stores energy, doesnt contribute
- Quality Factor
- causes maximally flat response with 0.707; 1 - overdamped, critically damped, 0.5 - underdamped
- Phasors
- representation of elements with sinusoidally varying points on a graph; vectors can be described on the basis of a plane
- Virtual Ground
- voltage at negative input of op amp = to positive input when there is negative feedback, and the positive input is grounded; that point is zero without the terminal actually being grounded; effect of grounding one of the terminals
- Instrumentation Amplifier
- Differential amp with really high input impedance and CMRR; two amps act as buffers, one acts as differential amp
- Unity Gain Bandwidth
- gain bandwidth product, bandwidth of a op amp at unity gain, as specified by the operator; open loop gain x cut off frequency
- Seebeck Effect
- change in voltage created by material property change by two dissimalr metals caused by temperature change
- Phase Distortion
- non-linear phase graph based on frequency giving different phases at different frequencies , so superpositioning causes distortion
- Integral Linearity Error
- error is how far it strays from a perfectly straight line in a A/D Converter, maximum deviation from ideal case
- Slew Rate
- rate at which op amp can charge/ discharge
- Passband Ripple
- effect caused in real filters and amplifiers of the passband not being a single gain but having a fluctuating gain as you go through the passband; can draw bode plot with ripple in max gain
- Differential Linearity Error
- error in an a/d converter which is the whole slope moved / shifted over, but is still linear; every bit is wrong, by a variability. i.e. a bit is supposed to be 1.0, but is 0.8, cuz every step doesnt always have the same amount of voltage;p 160; missing bits...
- Instrumentation Amplifier
- differential amp with really high input impedance and CMRR; two amps act as buffers, one acts as differential amp
- Differential Input Impedance
- in an IA - input impedance where the differential signal (difference between the two input signals) sees when entering it, which is lower than the common mode impedance
- Instrumentation Amplifier
- differential amplifier with CMRR; high CMRR = low noise; diff amp has balanced input impedences causing high CMRR and having two voltage sources; in an IA - input impedance where the differential signal (difference between the two input signals) sees when entering it, which is lower than the common mode impedance
- Generalized First Order Low Pass Filter
- a circuit that attenuates frequencies above a cut off frequency defined as being 1/2Pi RC --> write formula; passive has no gain, but has a gain of G; rolls off at -20dB per decade
- Binary Coded Decimal
- a way to represent a decimal number in binary code; used in D/A converters depending on input, may mean different voltage, cuz different kinds of binary (signed,unsigned) know what kind of binary input to know what to translate the output voltage to
- Inductive Reactance
- jwL; complex component of Impedance of an inductor
- Equivalent Voltage Source
- a Thevinin Equivalent , network of sources that can be represented as one voltage source; outside sources looking in can't tell the difference
- Voltage Divider
- a method of easily represetning voltage drops across two resistors in series
- Virtual Short Circuit
- two equipotential points caused by negative feedback loop in an operational amplifier
- Maximally Flat Response
- quality Factor is Q = 0.707, smallest amount of offshoot going up the magnitude/frequency plot; Butterworth filter exhibits this characteristic
- Superposition
- concept of removing certain sources from circuit and combining
- Hold Mode Droop
- error caused by capacitor leakage when sample/hold is turned on/off
- Quantization Error
- is Q in a A/D converter; how far voltage gets away from the binary word that is approximating it; due to not enough bits; insufficient resolution of D/A converter; value is least significant bit ... +/- least significant bit
- Full-Power Bandwidth
- highest frequency that a full scale frequency an be developed, an op amp can work at; consequence of having a non-infinite slew rate; op amp with too high frequency wont have negative feeback occur fast enough and will breakdown at freqs higher than that; full power is highest frequency that the opamp can still do negative feedback
- Transconductance Amplifier
- VCIS - voltage controlled current source; example : having a op-amp without reisstor on feedback loop, so theres output curent, but no voltage; non inverting amp with no negative feedback resistor
- Passive Transducer
- a transducer that modifies a signal but does not provide its own; only takes or draws power, but does not generate it
- Astable Circuit
- circuit created by positive feedback loop with no stable state; creates an output square wave
- Common Mode Input Impedance
- like diff input impedance, looking int an IA that a common mode signal sees; generally much higher than differential input impedance
- Output Impedance
- the impedance a load will see when looking back on the circuit
- Offset Voltage
- voltage of diff amp when both inputs are grounded; voltage leakage caused by dc sources in op amps causing error in voltage output in op amp. can be found by grounding inputs and calculating output voltage