Synonym polar direct-current telegraph transmission.

Synonym double-ended synchronization.

A queue in which the contents may be changed by adding or removing items at either end.

For two connected exchanges in a communications network, a synchronization control scheme in which the phase error signals used to control the clock at one exchange are derived by comparison with the phase of the incoming digital signal and the phase of the internal clocks at both exchanges. Synonym double-ended control.

Frequency-shift keying in which two telegraph signals are multiplexed and transmitted simultaneously by frequency shifting among four frequencies.

AM transmission in which both sidebands and the carrier are transmitted.

Transmission in which (a) the frequencies produced by amplitude modulation are symmetrically spaced above and below the carrier and (b) the carrier level is reduced for transmission at a fixed level below that which is provided to the modulator.
Note: In DSB-RC transmission, the carrier is usually transmitted at a level suitable for use as a reference by the receiver,… (Read More →)

Transmission in which (a) frequencies produced by amplitude modulation are symmetrically spaced above and below the carrier frequency and (b) the carrier level is reduced to the lowest practical level, ideally completely suppressed.
Note: DSB-SC transmission is a special case of double-sideband reduced carrier transmission.

A single-mode fiber that has two claddings.
Note 1: Each cladding has a refractive index that is lower than that of the core. Of the two claddings, inner and outer, the inner cladding has the lower refractive index.
Note 2: A doubly clad fiber has the advantage of very low macrobending losses. It also has two zero-dispersion points, and low… (Read More →)

A device for performing frequency translation in such a manner that the output frequencies are lower in the spectrum than the input frequencies.