Delay Spread An effect of multi-path for a digital interface in which multiple reflections of the same signal arrive at the receiver at different times, creating a noticeable degradation in signal quality. Demark The point of demarcation between equipment and facility or between outside plant facilities and premises distribution. Demodulation The extraction of the modulation or information from a radio-frequency current. Demographics Breakdown of television viewers by such factors as age, sex, income levels, education and race. Demultiplexer (DEMUX) A module that separates two or more signals previously combined by compatible multiplexing equipment. Multiplexer (MUX) – Demultiplexer (DEMUX) Diagram courtesy of Fiber Optics Info, Dense Wavelength Division Multiplexing (DWDM) A technology that provides, in fiber, the equivalent of frequency division multiplexing in metallic wire. Separate parallel channels are transmitted on a single fiber, with one wavelength for each channel. Current products enable 16 channels of 2.5Gb each for a total of 50Gb per fiber. DWDM can operate over existing single-mode fiber, and therefore reduce upgrade costs. DWDM permits transmission of closely spaced wavelengths in the 1550 nm region over a single optical fiber. Wavelength spacings are usually 100 GHz or 200 GHz which corresponds to 0.8 nm or 1.6 nm. DWDM bands include the C-Band, the and the L-Band. See also Coarse Wavelength Division Multiplexing (CWDM). DWDM Diagram courtesy of Fiber Optics Info, De-QPSK Differential Quadrature Phase Shift Keying DER Dynamic Extinction Ratio, ERRF; measured by applying an RF electrical signal at the RF input port of an optical intensity modulator, the DC bias voltage being tuned so as to set the modulator at the desired operating point (this operating point may be positive or negative quadrature, minimum, maximum or any other point of the transfer function depending on the application). ERRF is application dependent. For digital applications, the RF electrical
Delay Spread An effect of multi-path for a digital interface in which multiple reflections of the same signal arrive at the receiver at different times, creating a noticeable degradation in signal quality. Demark The point of demarcation between equipment and facility or between outside plant facilities and premises distribution. Demodulation The extraction of the modulation or information from a radio-frequency current. Demographics Breakdown of television viewers by such factors as age, sex, income levels, education and race. Demultiplexer (DEMUX) A module that separates two or more signals previously combined by compatible multiplexing equipment. Multiplexer (MUX) – Demultiplexer (DEMUX) Diagram courtesy of Fiber Optics Info, Dense Wavelength Division Multiplexing (DWDM) A technology that provides, in fiber, the equivalent of frequency division multiplexing in metallic wire. Separate parallel channels are transmitted on a single fiber, with one wavelength for each channel. Current products enable 16 channels of 2.5Gb each for a total of 50Gb per fiber. DWDM can operate over existing single-mode fiber, and therefore reduce upgrade costs. DWDM permits transmission of closely spaced wavelengths in the 1550 nm region over a single optical fiber. Wavelength spacings are usually 100 GHz or 200 GHz which corresponds to 0.8 nm or 1.6 nm. DWDM bands include the C-Band, the and the L-Band. See also Coarse Wavelength Division Multiplexing (CWDM). DWDM Diagram courtesy of Fiber Optics Info, De-QPSK Differential Quadrature Phase Shift Keying DER Dynamic Extinction Ratio, ERRF; measured by applying an RF electrical signal at the RF input port of an optical intensity modulator, the DC bias voltage being tuned so as to set the modulator at the desired operating point (this operating point may be positive or negative quadrature, minimum, maximum or any other point of the transfer function depending on the application). ERRF is application dependent. For digital applications, the RF electrical
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