"' Dual-polarization quadrature phase shift keying "'( DPQPSK ) or "'dual-polarization QPSK "'- involves the polarization multiplexing of two different QPSK signals, thus improving the spectral efficiency by a factor of 2.
12.
The Infinera super-channel solution was first deployed in mid-2012, and consists of a ten-carrier, 500-Gbit / s Polarization Multiplexed Quadrature Phase Shift Keying ( PM-QPSK ) super-channel implemented on a single line card.
13.
Weightless-N is designed around a differential binary phase shift keying ( DBPSK ) digital modulation scheme to transmit within narrow frequency bands using a frequency hopping algorithm for interference mitigation and enhanced security.
14.
Previous systems using phase shift keying ( PSK ) encoded two bits ( or sometimes three ) per symbol by slightly delaying or advancing the signal's phase relative to a set carrier tone.
15.
Digital systems typically use data rates in the 1, 200 19, 200 kilobit-per-second rates and may employ modulation schemes such as frequency shift keying, audio frequency shift keying, or quadrature phase shift keying to encode characters.
16.
A high data rate is squeezed from the low frequency by modulating a 15-kilohertz carrier wave using a technique called phase shift keying, the same method the latest modems use to send data along conventional phone lines at high speed.
17.
By contrast, the original ITU V . 22 standard, which could transmit and receive four distinct symbols ( two bits per symbol ), transmitted 1, 200 bits by sending 600 symbols per second ( 600 baud ) using phase shift keying.
18.
The modulation scheme for IS-54 is 7C / 4 differential quaternary phase shift keying ( DQPSK ), otherwise known as differential 7t / 4 4-PSK or ? / 4 DQPSK . This technique allows a bit rate of 48.6 kbit / s with 30 kHz channel spacing, to give a bandwidth efficiency of 1.62 bit / s / Hz.
