T12 ATI Study Guide Exam Practice Questions And Answers/2024.

transmitter - correct answer Puts LF information to be sent onto a higher frequency and amplifies it transmitting medium - correct answer The means by which the signal travels from transmitter to receiver receiver - correct answer Extracts the information from the signal sent by the transmitter and reproduces it in a usable form Types of transmitting mediums - correct answer Free space, transmission lines, waveguides, optical fibers Audio Frequency - correct answer Any frequency audible to the human ear 20Hz to 20kHz Radio frequency - correct answer Frequency of electromagnetic energy 30Hz to 30kHz carrier frequency - correct answer Any electromagnetic frequency that can be modulated to transmit information Modulation - correct answer Modification of signal to carry information amplitude modulation - correct answer Method of varying the amplitude of a signal to transmit information Detection - correct answer Process of extracting information from a signal frequency modulation - correct answer Method of varying the frequency of a signal to transmit information Continuous wave modulation - correct answer Interrupting a continuous RF carrier to communicate like Morse code Very Low Frequency (VLF) - correct answer Fleet communications or navigation 3 KHZ - 30 KHz Low Frequency (LF) - correct answer Radio communications 30 KHZ - 300 KHz Carrying conductors - correct answer Create electric field and magnetic field electric field - correct answer E field magnetic field - correct answer H field Electromagnetic conversion - correct answer Used to convert all air traveling signals from electrical energy to electromagnetic energy Radio frequency interference (RFI) - correct answer From radio transmitter Electromagnetic interference (EMI) - correct answer Any other source thats not a radio transmitter Refraction - correct answer The bending of a wave as it passes at an angle from one medium to another of a different density Diffraction - correct answer Radio waves bend around and obstacle Reflection - correct answer Radio waves bounce off a surface 2 types of space waves - correct answer Direct waves and ground waves Direct Waves - correct answer Limited to line of sight transmission Ground Reflected Wave - correct answer Reflected off of Earth surface Ground wave - correct answer Radio waves traveling near the surface of the ground that are limited to short range communication The higher the conductivity of the surface... - correct answer The lower the attenuation Sky Waves - correct answer Waves used for long distances that reflect off of the ionosphere In order to be transmitted... - correct answer A signal must be converted from audio to an electric signal What does modulation vary? - correct answer Amplitude, frequency, or phase Two requirements for amplitude modulation - correct answer An RF carrier and intelligence Upper sideband - correct answer Sum frequencies above the carrier frequency Lower sideband - correct answer Difference frequencies below the Carrier frequency Heterodyning - correct answer Combining two frequencies to produce four output frequencies