QAM

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QAM

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

QAM

In Q, or basic telecommunication code, it means, “What is the latest met (weather)?”
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

QAM

(1)

QAM

(2)
Quality Assurance Management.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

QAM

(1) (Quality Assessment Measurement) A system used to measure and analyze voice transmission.

(2) (Quantum Abstract Machine) An interface from Rigetti Computing for running programs in a hybrid classical/quantum computer environment. See QVM and quantum computing.

(3) (Quadrature Amplitude Modulation) A modulation technique that employs both phase modulation (PM) and amplitude modulation (AM). Widely used to transmit digital signals such as digital cable TV and cable Internet service, QAM is also used as the modulation technique in orthogonal frequency division multiplexing (see OFDM). The "quadrature" comes from the fact that the phase modulation states are 90 degrees apart from each other.

Analog QAM
Analog QAM uses two carriers 90 degrees out of phase with each other. Each carrier is modulated by an analog signal, and the resulting modulated waves are combined (see example below).

Digital QAM
In digital QAM, the number of modulation states determines how the digital signal is split up. For example, in 8QAM, each three bits of input alters the phase and amplitude of the carrier to derive eight unique modulation states (see example below).

In 16QAM, 32QAM, 64QAM, 128QAM, 256QAM, 512QAM and 1024QAM, from four to 10 bits generate from 16 to 1,024 modulation states respectively. See modulation and binary values.


Analog QAM
Analog QAM modulates two carriers 90 degrees out of phase with each from two analog input streams. The modulated carriers are combined and transmitted.







Digital QAM (8QAM)
In 8QAM, three input bits generate eight modulation states using four phase angles on 90 degree boundaries and two amplitudes (4 phases X 2 amplitudes = 8 states). Digital modulation greater than 8QAM is difficult to visualize.







Quadrature PSK (QPSK)
QPSK is like 4QAM without amplitude modulation. QPSK uses four phase angles to represent each two bits of input; however, the amplitude remains constant.
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References in classic literature ?
And by him that spake only as a philosopher, and natural man, it was well said, Pompa mortis magis terret, quam mors ipsa.
To say the truth, I require no more than that a man should have some little knowledge of the subject on which he treats, according to the old maxim of law, Quam quisque norit artem in ea se exerceat .
Erat quoque in eodem loco unica spinosa arbor, brevis admodum (quam nos ipsi nostris propriis oculis vidimus).
Social dissipation, fiant pilulae quam plurimae: to be taken, feasting, three times a day!"
Abbas beati Martini, SCILICET REX FRANCIAE, est canonicus de consuetudine et habet parvam proebendam quam habet sanctus Venantius, et debet sedere in sede thesaurarii .
If you will interpret the word INTOLERANCE as FIRMNESS OF PRINCIPLE, if you do not wish to condemn in the catholic soul of the Abbe de Sponde the stoicism which Walter Scott has made you admire in the puritan soul of Jeanie Deans' father; if you are willing to recognize in the Roman Church the Potius mori quam foedari that you admire in republican tenets,--you will understand the sorrow of the Abbe de Sponde when he saw in his niece's salon the apostate priest, the renegade, the pervert, the heretic, that enemy of the Church, the guilty taker of the Constitutional oath.
Orientis princeps Belzebub, inferni ardentis monarcha, et Demogorgon, propitiamus vos, ut appareat et surgat Mephistophilis Dragon, quod tumeraris: per Jehovam, Gehennam, et consecratam aquam quam nunc spargo, signumque crucis quod nunc facio, et per vota nostra, ipse nunc surgat nobis dicatus Mephistophilis!
* Bethany Quam, Group President, Europe & Australia segment, named Group President, Pet segment, effective October 1, 2019
Group president for Europe & Australia Bethany Quam, who joined General Mills in 1993, will replace Bishop, assuming the role of president of the pet segment with effect from October.
HONG KONG, June 3, 2019 - (ACN Newswire) - The award presentation ceremony of Quam IR Awards 2018 (QIRA) successfully took place on 31 May, 2019 at Four Seasons Hotel Hong Kong.
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