# Shared Flashcard Set

## Details

3C231 - Block II
Telecomunications Fundamentals
63
Computer Science
Professional
12/08/2008

Term
 A component consisting of two conducting surfaces (plates) seperated by an insulator.
Definition
 A Capacitor
Term
 What are the two types of capacitors?
Definition
 Fixed and variable
Term
 The measure of a capacitor's ability to store energy in the form of an electrostatic field
Definition
 Capacitance
Term
 The symbol for capacitance is ____ and is measured in _________.
Definition
Term
 When placing capacitors in series, what is the formula to find total capacitance?
Definition
 Ct  =             1                                  1_  +   1_  +   1_                     C1         C2      C3
Term
 When placing capacitors in parallel, what is the formula to find total capacitance?
Definition
 Ct = C1 + C2 + C3...
Term
 What is the formula for capacitive reactance (XC)?
Definition
 Xc =  __1__  or   _0.159__                  2∏fC               fC
Term
 What is the formula for inductance?
Definition
 L  =  N2Aµ       l
Term
 When placing indicators in series, what is the formula for total inductance?
Definition
 LT  =  L1 + L2 + L3 ...
Term
 When placing indicators in parallel, what is the formula for total inductance?
Definition
 LT =  _______1________                              _1_  +   1_ + _1_ ....                               L1         L2        L3
Term
 What are the formulas for time and frequency?
Definition
 t = 1/f    f = 1/t
Term
 What are the two formulas for calculating wavelength?
Definition
 λ = v/f   and vt
Term
 What is the formula for inductive reactance?
Definition
 XL = 2∏fL   or   6.28fL
Term
 What is the formula for effective voltage?
Definition
 Eeff = .707 x Epk
Term
 What is a device designed to control current flow through a circuit?
Definition
 Resistor
Term
 What do we call the movement of electrons from atom to atom?
Definition
 Current
Term
 The chemical reaction that causes the atoms on the positive side of a battery to lose electons, while the negative side gains electrons is called what?
Definition
 Ionization
Term
 What kind of current flows in only one direction?
Definition
 Direct Curent  (DC)
Term
 What are 4 requirements for a basic circuit?
Definition
Term
 What type of circuit provides only one path of current flow?
Definition
 Series Circuit
Term
 What is the electrical energy that causes electrons to move through a circuit?
Definition
 Voltage
Term
 Ohm's Law part 2 of 2 states that current is __________ proportional to resistance?
Definition
 Inversely
Term
 What effect do insulators have on current flow?
Definition
 The inhibit current flow
Term
 Ohm's Law part 1 of 2 states current is _____________ proportional to voltage.
Definition
 Directly
Term
 What do you call electrons in the outermost orbit of an atom?
Definition
 Valence
Term
 What kind of resistor is the most common type of fixed resistor and used in low current applications?
Definition
 Carbon Resistor
Term
 What is the most common type of AC waveform, representing voltage and current?
Definition
 Sine Wave
Term
 What's the difference between a series and a parallel circuit?
Definition
 A Series has only one path and a Parallel has two paths
Term
 At what point in a sinewave cycle is it possible to measure the peak voltage?
Definition
 At the peak of the alternation
Term
 After a sine wave has gone through one cycle, it repeats itself to form a ___________.
Definition
 Wave Train
Term
 What is a graphic representation of how voltage and current changes in amplitude and direction?
Definition
 Sine Wave
Term
 Frequency and the time of a sine wave are _________ proportional.
Definition
 Inversely
Term
 What happens to the wavelength if the time of one cycle increases?
Definition
 It increases
Term
 What happens to wavelength if frequency increases?
Definition
 It decreases
Term
 What 3 conditions must exist for sine waves to be considered in-phase?
Definition
 Must be of the same frequencyReach peaks at the same timePass zero axis at the same time
Term
 In a capacitor, what phase relationship exists between current and voltage?
Definition
Term
 What is the opposition that a capacitor offers to AC current flow?
Definition
 Capacitive reactance
Term
 If frequency goes up, what happens to capative reactance?
Definition
 Decreases
Term
 What is the symbol for inductance?
Definition
 L
Term
 What is the unit of measure for inductance?
Definition
 (H) Henry
Term
 What happens to inductive reactance if Frequency (f) increases?
Definition
 It will increase
Term
 What is the frequency that causes XC and XL to become equal?
Definition
 The Resonant Frequency
Term
 Which type of signal format alternates the voltage polarity between successive mark bits?
Definition
 AMI
Term
 How does quasi-analog signal format differ from the other signal formats?
Definition
 Its an analog signal with digital information
Term
 What is the formula for upper sideband?
Definition
 fc+fm
Term
 What are the 2 types of detection for PSK?
Definition
 Fixed Reference and Differential
Term
 Which PSK process uses 2 input data bits to make an output decision?
Definition
 QPSK
Term
 Which modulation technique must you use for data rates over 35 Mb/S?
Definition
 QAM
Term
 What distortion is created by the delta modulation process?
Definition
Term
 How does CVSD differ from DM?
Definition
 It has non uniform steps
Term
 What states that for a signal to be reproduced accurately, it must be sampled at twice the highest frequency?
Definition
 Nyquist Theorom
Term
 What is the sample rate for a voice signal?
Definition
 8000 times per second or 0-4kHz
Term
 What logarithmic scale has 16 chords and 16 steps with each chord?
Definition
 Mu-Law 255
Term
 What is the sample rate of ADPCM?
Definition
 4 Bit word per sample
Term
 What do the 2nd, 3rd, and 4th bits represent in a PCM word?
Definition
 The highest chord in the PAM sample achieved in the quantizer
Term
 What do the last four bits of a PCM word represent?
Definition
 The step to which the sample was rounded
Term
 Where is the Conditioned diphase interface (CDI) technique predominately used?
Definition
 Tactical Environment
Term
 What is the part of the signal that occupies the shortest interval of a signaling code?
Definition
 Unit Interval
Term
 What is the amount of time a digital signal is left at a particular voltage to indicate a value?
Definition
 Bit Interval
Term
 What is counting the number of bits recieved in a specific time interval (usually one second)?
Definition
 Bit Count Integrity
Term
 What is the measurement of the signaling speed of a data transmission device?
Definition
 Baud Rate
Term
 What is  the term that describes when a carrier is at a frequency other than the center frequency?
Definition
 Deviation
Term
 What happens to wavelength if frequency increases?
Definition
 Gets shorter
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