QAM: Quadrature Amplitude Modulation; A methodfor encoding digital data in an analog signal in which each com-binationof phase and amplitude represents one of sixteen four bit patterns. Thisis required for fax transmission at 9600 bits per second. One of the variousxDSL modulationmethods.
QoS: Quality of Service
QPR: Quadrature PartialResponse
QPSK: QuadraturePhase Shift Keying; a passband signal generated through modulating complexdata symbols with four different angles of a carrier frequency.
Quadrature: Electronics. therelation between two signals having the same frequency that differ in phaseby 90 degrees.
Quantize: A step in the process of convertingan analog signal into a digital signal. Quantization measures a sampleto determine a representative numerical value that is then encoded. Thethree steps in analog-to-digital conversion are sampling, quantizing, andencoding.
Quaternary: refers to a four-level symbol.