RADIO COMMS QPAL Flashcards
The SENIOR WIRELESS OPERATOR who tRANSMITTED THE DISTRESS CALL In Titanic
JOHN PHILLIPS
this laws form the fundamental principles of circuit analysis.
KIRCHHOFF’S CIRCUIT LAWS
By applying Kirchhoff’s CIRCUIT LAWS alongside equations for specific components like ________, we possess the essential means to begin analyzing circuits.
resistors, capacitors, and inductors
GERMAN PHYSICIST
KONIGSBERG, PRUSSIA
CONDUCTION OF ELECTRICITY
GUSTAVROBERT KIRCHHOFF
GUSTAVROBERT
KIRCHHOFF BIRTHDAY
BORN ON MARCH 12, 1824
According to the first
law, the total
current entering a
junction or a node is
equal to the charge
leaving the node as
no charge is lost.
KIRCHHOFF’S FIRST LAW “CURRENT LAW”
The current is the
flow of charge past
some point.
KIRCHHOFF’S FIRST LAW “CURREN TLAW”
If the current does
not leak out along
the way, the current
in both components
must be the same,
and we write I1 = I2
KIRCHHOFF’S FIRST LAW “CURREN TLAW”
The voltage around a loop equals the sum of every voltage drop in the same loop for any closed network and equals zero.
KIRCHHOFF’S SECOND LAW
“VOLTAGE LAW”
We define voltage by relating electric charge and potential energy. V = E/Q
KIRCHHOFF’S SECOND LAW
“VOLTAGE LAW”
The units of voltage are volts, abbreviated as V. We can think of the voltage as the potential energy per unit charge. Often the voltage is called the potential, and that may help make the connection to potential energy clearer.
KIRCHHOFF’S SECOND LAW
“VOLTAGE LAW”
The number of times the signal makes a complete up an down cycle in one second.
FREQUENCY
The standard unit of measurement used for measuring frequency.
HERTZ(HZ)
Hertz comes from
German physicist
_____________ who
first demonstrated
radio waves.
Heinrich Hertz
A user can tweak the height of the carrier. If an input signal’s height varies with the loudness of a user’s voice and then adds this to the carrier, then the carrier’s amplitude will change corresponding to tho the input signal that’s been fed into it.
AMPLITUDE MODULATION(AM)
Frequency of an input signal can also be changed. If this input signal is added to the pure carrier wave, it will thereby change the frequency of the carrier wave. In that way, users can use changes of frequency to carry speech information.
FREQUENCY MODULATION(FM)
An _____ is
characterized by the
gain, which is the ratio
of output power to input
power. We write the
gain G as G = P/Pi.
amplifier
____ are also used
in transmitters to boost
low-power oscillator
signals.
Amplifiers
Sound waves have low frequencies (kHz) but radio signals are much higher. Receivers use __ to trick these high-frequency signals into dropping down to the lower audio range we can hear.
mixers
___ work by combining two signals and creating two new ones: a higher sum and a lower difference frequency.
Mixers
This is used to prevent unwanted signals from reaching your equipment, whilst allowing the wanted ones to pass through unaffected.
FILTERS
WHERE DOES THE FILTER APPLY?
power supplies, audio electronics, and radio communications.
Filters can be active or passive, and the four main types of filters are
low-pass, high-pass, band-pass, and notch/band-reject (though there arE also all-pass filters).
This is a radio receiver design that demodulates the incoming radio signal using synchronous detection driven by a local oscillator whose frequency is identical to, or very close to the carrier frequency of the intended signal.
DIRECT-CONVERSION RECEIVERS
