SUB-ELEMENT M Flashcards
What term describes a wide-bandwidth communications system in which the RF carrier frequency varies according to some predetermined sequence?
A. Amplitude compandored single sideband.
B. SITOR.
C. Time-domain frequency modulation.
D. Spread spectrum communication.
D
Name two types of spread spectrum systems used in most RF communications applications?
A. AM and FM.
B. QPSK or QAM.
C. Direct Sequence and Frequency Hopping.
D. Frequency Hopping and APSK.
C
What is the term used to describe a spread spectrum communications system where the center frequency of a conventional carrier is altered many times per second in accordance with a pseudo-random list of channels?
A. Frequency hopping.
B. Direct sequence.
C. Time-domain frequency modulation.
D. Frequency compandored spread spectrum.
A
A TDMA radio uses what to carry the multiple conversations sequentially?
A. Separate frequencies.
B. Separate pilot tones.
C. Separate power levels.
D. Separate time slots.
D
Which of the following statements about SSB voice transmissions is correct?
A. They use A3E emission which are produced by modulating the final amplifier.
B. They use F3E emission which is produced by phase shifting the carrier.
C. They normally use J3E emissions, which consists of one sideband and a suppressed carrier.
D. They may use A1A emission to suppress the carrier.
C
What are the two most-used PCS (Personal Communications Systems) coding techniques used to separate different calls?
A. QPSK and QAM.
B. CDMA and GSM.
C. ABCD and SYZ.
D. AM and Frequency Hopping.
B
What is a CODEC?
A. A device to read Morse code.
B. A computer operated digital encoding compandor.
C. A coder/decoder IC or circuitry that converts a voice signal into a predetermined digital format for encrypted transmission.
D. A voice amplitude compression chip.
C
The GSM (Global System for Mobile Communications) uses what type of CODEC for digital mobile radio system communications?
A. Regular-Pulse Excited (RPE).
B. Code-Excited Linear Predictive (CLEP).
C. Multi-Pulse Excited (MPE).
D. Linear Excited Code (LEC).
A
Which of the following codes has gained the widest acceptance for exchange of data from one computer to another?
A. Gray.
B. Baudot.
C. Morse.
D. ASCII.
D
The International Organization for Standardization has developed a seven-level reference model for a packet-radio communications structure. What level is responsible for the actual transmission of data and handshaking signals?
A. The physical layer.
B. The transport layer.
C. The communications layer.
D. The synchronization layer.
A
What CODEC is used in Phase 2 P25 radios?
A. IWCE
B. IMBC
C. IMMM
D. AMBE
D
The International Organization for Standardization has developed a seven-level reference model for a packet-radio communications structure. The _______ level arranges the bits into frames and controls data flow.
A. Transport layer.
B. Link layer.
C. Communications layer.
D. Synchronization layer.
B
What is a SDR?
A. Software Deviation Ratio.
B. Software Defined Radio.
C. SWR Meter.
D. Static Dynamic Ram.
B
What does the DSP not do in a modern DSP radio?
A. Control frequency.
B. Control modulation.
C. Control detection.
D. Control SWR.
D
Which statement best describes the code used for GMDSS-DSC transmissions?
A. A 10 bit error correcting code starting with bits of data followed by a 3 bit error correcting code.
B. A 10 bit error correcting code starting with a 3 bit error correcting code followed by 7 bits of data.
C. An 8 bit code with 7 bits of data followed by a single parity bit.
D. A 7 bit code that is transmitted twice for error correction.
A
