Glossary of abbreviations

A/D conversion (analogue-to-digital conversion) The process of converting a time-continuous analogue signal to a sampled digital representation
Additive White Gaussian Noise (AWGN) The term describing a noise signal which has a flat power spectral density with frequency
Amplitude Shift Keying (ASK) A digital modulation format where information is conveyed in the amplitude of a carrier signal
Automatic Repeat Request (ARQ) Protocol for dealing with data words that are corrupted by errors whereby the receiving system requests a re-transmission of the word(s) in error
BCH A type of block coding of data words named after the inventors Bose, Chaudhuri and Hocquenghem
Binary Phase Shift Keying (BPSK) Digital modulation format where information is conveyed in the phase of a carrier signal: usually 0o and 180o
Bit error rate (BER) A measure of the number of bit errors occurring in a transmitted data sequence
Code Division Multiple Access (CDMA) Method of combining multiple users on a given channel bandwidth using unique spreading codes, or hopping patterns to distinguish any given user
Continuous Phase Frequency Shift Keying (CPFSK) Digital modulation format where information is conveyed in the frequency of a carrier signal ensuring that the phase is continuous between symbol transitions
D/A conversion (digital-to-analogue conversion) The process of converting a discrete time digital representation of a waveform to a continuous analogue voltage equivalent
dBc The level of a signal in dB relative to a wanted carrier signal level
dBm the level of a signal in dB relative to 1mW (0dBm)
Differential Phase Shift Keying (DPSK) Digital modulation format where information is conveyed in the phase difference of a carrier signal between consecutive symbols
Differentially Encoded Phase Shift Keying (DEPSK) Digital modulation format where data is pre-coded to convey information in the change of state between consecutive bits, to overcome the phase ambiguity problem with coherent phase shift keying
Digital Audio Broadcasting (DAB) The generic name given to the new generation of radio transmission using digitally encoded audio waveforms
Digital Video Broadcasting (DVB) The generic name for the new generation of image and sound transmission using a digitised version of the image signal
Dynamic Channel Multi-carrier Architecture (DC/MA) A proprietary radio system designed by Wireless Systems International for ComSpace Corporation
Eb Symbol denoting the energy required to represent 1 bit of information in the modulated signal
Es Symbol denoting the energy required to represent 1 symbol of information in the modulated signal
European Telecommunications Standards Institute (ETSI) The body in Europe responsible for setting standards relating to wireless communications
Feed Forward Signal Regeneration (FFSR) A method for correcting for multipath fading and frequency error in mobile radio systems using a pilot reference tone
Forward Error Correction (FEC) An error correction method allowing detection and correction of bit or word errors without the need to re-transmit the data
Frequency Division Multiple Access (FDMA) Method of combining multiple users on a given channel bandwidth using unique frequency segments
Frequency Shift Keying (FSK) Digital modulation format where information is conveyed in the frequency of a carrier signal
Gaussian Minimum Shift Keying (GMSK) Digital modulation format where information is conveyed in the frequency of a carrier signal, where the incoming data is first shaped with a Gaussian low-pass filter
GSM (Global System for Mobile communications) A cellular radio standard using digital GMSK modulation
Intermediate Frequency (IF) A special frequency used in radio systems as part of the up-conversion or down-conversion process; usually where the channel selection is made
Intersymbol interference (ISI) Interference between adjacent symbols often caused by system filtering, dispersion in optical fibres, or multipath propagation in radio system
International Telecommunications Union (ITU) The body overseeing standards and regulation for the wired communications industry
M-ary Amplitude and Phase Keying (M-ary APK) Digital modulation format where information is conveyed in the amplitude and phase of a carrier signal
M-ary Amplitude Shift Keying (M-ASK) Digital modulation format where information is conveyed in the 'M' amplitudes of a carrier signal
M-ary Phase Shift Keying (M-PSK) Digital modulation format where information is conveyed in the 'M' phases of a carrier signal
M-ary Quadrature Amplitude Modulation (M-QAM) Digital modulation format where information is conveyed in the 'M' amplitude and phase combinations of a carrier signal
Minimum Shift Keying (MSK) Digital modulation format where information is conveyed in the frequency of a carrier signal with modulation index equal to half the symbol period
N0 The noise power density measured in Watts/Hz
Non Return to Zero (NRZ) Binary data encoding format
ON-OFF Keying (OOK) Digital modulation format where information is conveyed by switching on and off a carrier signal
Orthogonal Frequency Division Multiplexing (OFDM) Modulation format where information is sent over multiple parallel adjacent frequency channels where the carrier frequencies are orthogonal
Pb Probability of receiving a data bit in error
PCS (Personal Communications System) Common term for cellular radio predominantly in North America
Phase Locked Loop (PLL) Feedback control circuit for tracking the frequency and phase of an incoming signal, often used in modem carrier recovery circuits
Ps Probability of receiving a data symbol in error
Quadrature Amplitude Modulation (QAM) Digital modulation format where information is conveyed in the amplitude and phase of a carrier signal
Quadrature Phase Shift Keying (QPSK) Digital modulation format where information is conveyed in four equi-spaced phases of a carrier signal
RF Radio Frequency
rms root mean square
RS (Reed–Soloman) A type of block code for error detection and correction
RX Short for receiver
S/N ratio Signal-to-noise ratio
Symbol Error Eate (SER) The probability of receiving a symbol in error (not to be confused with Bit Error Rate)
Tb The period of 1 data bit
TETRA (Trans European Trunked Radio) The name of the ETSI-standardised radio system for private and public mobile two-way radio applications
Time Division Multiple Access (TDMA) Method of combining multiple users on a given channel bandwidth using unique time segments
Trellis Coded Modulation (TCM) Method of coding multiple symbols to give improved symbol error rate performance in noisy conditions
TX Short for transmitter
Voltage Controlled Crystal Oscillator (VCXO) A circuit whose oscillating frequency is tied to that of a crystal (fundamental or harmonic)
Voltage Controlled Oscillator (VCO) A circuit whose output frequency varies in sympathy with an input voltage
Wavelength Division Multiplexing (WDM) Method of combining multiple users on a given channel bandwidth using unique wavelengths (or frequencies as in FDMA)