Eight ambiguities: four associated with phase of carrier signal in absence of ambiguity in direction of rotation of carrier phase, and another four associated with carrier phase in presence of phase-rotation ambiguity. Report discusses several techniques for resolution of phase ambiguities in detection and decoding of radio signals modulated by coherent quadrature phase-shift keying ( QPSK) and offset QPSK (OQPSK). Compared with single-channel regeneration, multichannel regeneration brings 0.4-dB OSNR penalty when the value of BER is 10-3, which shows the cross talk in regeneration process is negligible. Optical signal-to-noise ratio improvement is validated by bit error rate measurements. In addition, to avoid the effect of overlapping frequency, frequency spans between pumps and signals are set to be nonintegral multiples. The number of waves is reduced to decrease the cross talk caused by undesired nonlinear interaction during the coherent superposition process. By utilizing conjugate pump and common pump in a highly nonlinear optical fiber, degenerate four-wave mixing process is observed, and QPSK signals are regenerated. Wang, Hongxiang Wang, Qi Bai, Lin Ji, YuefengĪ scheme is proposed to realize the all-optical phase regeneration of four-channel quadrature phase shift keying ( QPSK) signal based on phase-sensitive amplification. The direct down-conversion technique is applicable to next-generation high-speed wireless access communication systems in the millimeter-wave band.Īll-optical simultaneous multichannel quadrature phase shift keying signal regeneration based on phase-sensitive amplification 1-8-G-baud quadrature phase-shift keying ( QPSK) signals are transmitted successfully with observed bit error rates within a forward error correction limit of 2Ã-10-3 using radio over fiber (RoF) techniques. The IQ imbalance of the converter is measured within a range of +/-10 degrees in an intermediate frequency of DC-26.5 GHz. The effects of in- phase/quadrature-phase (IQ) imbalances are evaluated with a direct IQ down-converter in the W-band (75-110 GHz). Suzuki, Meisaku Kanno, Atsushi Yamamoto, Naokatsu Sotobayashi, Hideyuki A 30-Gb/s optical 8PSK is experimentally demonstrated using the proposed solution.Įvaluation of quadrature-phase-shift-keying signal characteristics in W-band radio-over-fiber transmission using direct in- phase/quadrature-phase conversion technique Therefore, the proposed transmitter structure has potential to be deployed as a versatile transmitter for synthesis of several different multi-level modulation formats for the future dynamic optical networks. The transmitter configuration is based on two cascaded IQ modulators, which also could be used to generate other advanced multi-level formats like quadrature amplitude modulation (QAM) when different driving and bias conditions are applied. By cascading an S- QPSK and an R- QPSK, an optical 8PSK could be synthesized.

The concept of R- QPSK is proposed for the first time and applied to optical eight-ary phase-shift keying (8PSK) transmitter. On the other hand, when an IQ modulator is driven in an un-balanced manner with different amplitudes in in- phase (I) and quadrature (Q) branches, a rectangular QPSK (R- QPSK) could be synthesized. This conventional QPSK is referred to as square QPSK (S- QPSK) in this paper. Quadrature phase-shift keying ( QPSK) is usually generated using an in- phase/quadrature (IQ) modulator in a balanced driving-condition, showing a square-shape constellation in complex plane. Lu, Guo-Wei Sakamoto, Takahide Kawanishi, Tetsuya Rectangular QPSK for generation of optical eight-ary phase-shift keying. One suboptimum realization achieves the Nyquist rate of 2 bits/s/Hz using binary detection. An optimum class of pulse shapes for use in Q2PSK-format is presented.

Like MSK, Q2PSK also has self-clocking and self-synchronizing ability. This coded signal substantially outperforms MSKS and TFM (time-frequency multiplexing) in bandwidth efficiency. However, a simple block coding provides a constant envelope. Without additional constraints, Q2PSK does not maintain constant envelope. With simple sinusoidal and cosinusoidal data pulses, the Eb/N0 requirement for Pb(E) = 10 to the -5 is approximately 1.6 dB higher than that of MSK. However, the bit error rate performance depends on the choice of pulse pair. It uses two data shaping pulses and two carriers, which are pairwise quadrature in phase, to create a four-dimensional signal space and increases the transmission rate by a factor of two over QPSK and MSK. Quadrature-quadrature phase-shift keying (Q2PSK) is a spectrally efficient modulation scheme which utilizes available signal space dimensions in a more efficient way than two-dimensional schemes such as QPSK and MSK (minimum- shift keying).

Quadrature phase shift