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To: ftth who wrote (5938)	11/11/1999 8:43:00 PM
From: Phil(bullrider)	Respond to of 12823

Dave, Thanks, I printed your post for further study. Have fun, Phil

To: ftth who wrote (5938)	11/11/1999 9:44:00 PM
From: ftth	Respond to of 12823

Bullrider, just came across this also (an acronym list): csdmag.com (click on "The Cornerstone of Building Blocks" under "Columns") It only covers A-H this month. Under "News" there's also a bit of info on E911 and the personal location system, which was discussed some time back. ----------------------------------------- A-H Acronyms copied below for posterity: A A/D. Analog-to-digital converter or conversion – The process of sampling an analog waveform and describing it in terms of binary digits (June, July 98). ACI. Adjacent channel interference – The phenomenon whereby channels that are beside one another in the frequency domain may have some spectral overlap, causing impairment (July 99). ADC. See A/D. ADSL. Asymmetric digital subscriber line – Standard for high-speed data over twisted-pair copper as a function of loop length. (Downstream: 1.5 to 9 Mbps, Upstream: 16 to 640 kbps) (Feb. 97). AGC. Automatic gain control – Receiver function that generates constant power output under varying power input (Oct. 99). ALC. Automatic level control – (See AGC) Sometimes used for subsystems with less dynamic variation. AM. Amplitude modulation – Classic AM radio format. Also, AM optics refers to analog fiber optic links used in cable systems (Feb. 97). AM/PM. Amplitude modulation-to-phase modulation conversion – An impairment generated when a signal with amplitude variation impinges on a device that con- verts some of this variation to output signal phase changes (Jan. 97). AM-VSB. AM-vestigial sideband modulation – Classical method used to modulate carriers in traditional analog video (May 97). ARQ. Automatic repeat request – Rudimentary transmission error protection whereby the receiver requests a retransmission when it detects (using CRC) that errors have occurred in a frame. ASIC. Application-specific integrated circuit – Custom IC developed for a targeted application (May 97). ATM. Asynchronous transfer mode – A packet-switched network protocol, which uses a pre-established connection route (Jan. 98). AWGN. Additive white Gaussian noise – The common wideband channel thermal noise impairment, on which signal-to-noise ratio (SNR) is typically based (Jan. 97). -------------------------------------------------------------------------------- B BCD. Binary coded decimal – A format for expressing decimal numbers with binary digits (June 98). BCH. Bose-Chaudhuri-Hocquenghem – Co-authors of the so-named family of commonly-used linear block codes, a type of forward error correction (May 99). BER. Bit error rate or bit error ratio – A figure of merit for a digital communication link. It is the fraction of bits received in error divided by the total number of bits transported (Jan., June 97). BPSK. Binary phase shift keying – A digital modulation format where 1 and 0 are represented by phase shifts of 0º and 180º of the carrier (Oct. 97). BW. Bandwidth. -------------------------------------------------------------------------------- C C/I. Carrier-to-interference ratio – Also referred to as signal-to-interference (S/I) ratio. This is a quantification similar to SNR referring to the power ratio of the desired signal to an interference signal. It is typically of a narrowband nature (Feb. 98). CAP. Carrierless amplitude-phase modulation – Quadrature amplitude modulation (QAM)-type modulation format with a unique implementation twist designed for ADSL applications (Aug. 97). CATV. Community access television – Cable TV (Jan., Feb. 97). CCI. Cochannel interference – Spectral overlap of signals in adjacent systems, (spatially multiplexed wireless, for example) causing degradation in each (Jan. 97). CDF. Cumulative distribution function – Probability and statistics function used to calculate and plot, in a straightforward form, the likelihood of events (April 97). CDMA. Code division multiple access – Spread spectrum technique using high-speed pseudorandom (PN) codes to scramble data words and spread spectral occupancy for added robustness (Sept. 97). CNR. Carrier-to-noise ratio – Also known as SNR. A figure of channel quality merit, comparing desired signal power to undesired noise power. CNR is typically used in the analog video world (Jan. 97, March 98). CRC. Cyclic redundancy check – A simple form of error correction characterized by a checksum calculation (May 99). CW. Continuous wave – An unmodulated carrier. -------------------------------------------------------------------------------- D D/A. Digital-to-analog converter – The reverse of A/D, it generates analog output signal from binary input words (June, July 1998). DCT. Discrete cosine transform – A Fourier-like transform applied to picture elements to aid in data (video) compression (Oct. 1998). DDS. Direct digital synthesizer – Fine resolution digital frequency synthesis technology that uses a numerically controlled oscillator (NCO) to program the output frequency to the chosen value (Sept. 97, Feb. 99). DFE. Decision feedback equalizer – Digital communication receiver technology that uses data decisions to adjust its taps to correct for frequency response impairment (Aug. 97). DMT. Discrete multitone – The selected ADSL physical layer standard, which uses a multicarrier technique to transport data via multiple parallel subchannels per symbol transmission period (Jan. 97). DNL. Differential nonlinearity – An error associated with non-ideal A/D conversion (July 98). DOCSIS. Data Over Cable Service Interface Specification – The organization and document defining the cable modem standard. DQPSK. Differential quadrature phase shift keying – A modulation format using four phases (see QPSK), but transmitted so that the information is encoded in the difference from symbol to symbol for synchronization simplification purposes (May 97). DRO. Dielectric resonator oscillator – A type of high-performance microwave oscillator technology (Feb. 98). DSP. Digital signal processing – Use of digitized words processed by numerical calculations on a waveform sampled and encoded, using functions such as filtering, synchronization, and detection. (Nov. 98). DS-SS. Direct sequence spread spectrum – PN code-based spread spectrum as described in CDMA (Sept. 97). -------------------------------------------------------------------------------- E Eb/No. Energy-per-bit to noise density ratio – A common SNR-like figure of merit for digital communication systems, particularly those obeying Nyquist criteria. Also understood as SNR-per-bit, relates to BER for a given modulation type (Jan., June 97). Es/No. Energy-per-symbol to noise density ratio – A common SNR-like figure of merit for digital communication systems. Equivalent to SNR for systems obeying Nyquist criteria, it relates to BER for a given modulation type, and relates to Eb/No through number of bits per symbol (Jan., June 97). ECCM. Electronic counter-counter measures – Covert military communication field of design (Feb. 99). ECM. Electronic counter measures – Covert military communication field of design (Feb. 99). ENOB. Effective number of bits – Figure of merit for an A/D converter describing how many bits of effective resolution — below actual A/D word size — exist due to limitations in noise and distortion performance (June 98). -------------------------------------------------------------------------------- F FDMA. Frequency division multiple access – An approach to sharing a channel by separating the simultaneous users in frequency (Jan. 97). FEC. Forward error correction – Technique by which a data stream is modified to create added channel robustness, improving error rate performance (Jan., March 97). FEXT. Far-end crosstalk – A common telephony impairment created by physical twisted wire pairs sharing a bundle (Feb. 97). FFT. Fast Fourier transform – A hardware implementable algorithm for spectral analysis in signal processing applications, including basic OFDM systems (Aug. 97). FH-SS. Frequency-hopping spread spectrum – Technique of spectrum spreading performed to secure the data transmission by selecting among multiple possible tones based on a pseudorandom sequence (Feb. 99). FIR. Finite impulse response – Well-known linear phase digital filter type commonly used in DSP, which performs spectral modification in the discrete domain similar to the function of analog filters (Nov. 98). FM. Frequency modulation – Classic radio band signal format, modulating a carrier by having its frequency vary with the input waveform (May 97). FSE. Fractionally spaced equalizer – A digital receiver equalization technique based on adaptive filtering with half-symbol spaced taps. It provides improved timing robustness (Aug. 97). FSK. Frequency shift keying – A digital communication technique which chooses the carrier frequency from a predetermined set, based on the input data (May 97). FTTC. Fiber-to-the-curb – Usually associated with switched digital signaling to an optical network unit serving a small number of homes, where transformation to analog carries the signals the “last mile” (Feb. 97). FTTH. Fiber-to-the-home – Self explanatory “ultimate” solution (Feb. 97). -------------------------------------------------------------------------------- G GMSK. Gaussian minimum shift keying – A form of MSK used in wireless (see MSK) applications, which uses a filter with Gaussian impulse response, resulting in narrower spectral containment at the expense of adding dispersion (ISI) (May 97). GDV. Group delay variation – RF distortion impairment where different frequency components of a signal are passed through a device and receive different time delays (Nov. 98). -------------------------------------------------------------------------------- H HDSL. High speed digital subscriber line – Data transport standard for 1.5-Mbps copper twisted pair (May 98). HDTV. High definition television – Very high resolution picture technology (May 97, Sep. 98). HF. High frequency – RF band covering 3 to 30 MHz by IEEE designation. Associated in “Building Blocks” context often with ingress disturbances in return path cable systems (April 98). HFC. Hybrid fiber-coax – Typical architecture used in modern cable TV systems consisting of a mix of optics delivered to neighborhoods, and converted to RF for transmission to subscribers by fiber optic nodes (Feb. 97).