#ADVANTAGES OF OPTISYSTEM CODE#

Most recent works on N-WDM assume very small roll-off factors. Allowing for nonzero roll-off factors relaxes the constraints on the filter length and the tolerable jitter at expense of increasing ICI.

These constraints translate into ISI and ICI and therefore affect significantly the performance. However, N-WDM suffers from hardware implementation limitations such as the finite length of the pulse shaping filters, the timing jitter of the data sampling, and the finite resolution of the analog/digital converters (ADC, DAC). During the last years, RRC filtering with a close to 0 roll-off factor has attracted much research interest in order to maximize SE. The class of root-raised-cosine (RRC) functions is of particular interest because they satisfy the Nyquist criterion of zero inter-symbol interference (ISI) whatever the roll-off factor when applied at transmitter and receiver. N-WDM systems operate with shaping pulses having nearly rectangular frequency spectrum of bandwidth equal to the symbol rate. FranГ§ois Horlin, in Orthogonal Waveforms and Filter Banks for Future Communication Systems, 2017 4.3.1 Nyquist Wavelength Division Multiplexing (Nyquist-WDM) The large processing delay increases overhead for TDD link direction switching, which is not suitable for latency critical applications. For example, if filters with length equal to half OFDM symbol are used at the transmitter and at the receiver sides, then the filter processing delay is equal to one OFDM symbol. Another aspect of F-OFDM is that when long filters are used for an improved OOB suppression, there can be significant group delay due to the filtering. This is different from W-OFDM, whose construction does not change with the signal bandwidth (i.e., the pulse shape p does not change with signal bandwidth). The filter w t x is dependent on the signal bandwidth, which implies that the filter need to be dynamically designed or selected based on the signal bandwidth. Various window functions are common for the construction of FIR filters with different characteristics, for example, Hanning, Hamming, Blackman, Bartlett, and Kaiser window functions. Where h is an ideal bandpass filter with the selected signal bandwidth and w is a window function. Although the amplifier output pulse heights are measured in volts, the LL and UL discriminator settings are calibrated in other units, such as, kiloelectron volts (keV), which allows correlation between amplifier output pulse heights from the crystal detector and the actual gamma-ray energies absorbed by the detector. According to the settings of the LL and UL discriminators, the instrument circuitry will allow only pulses of magnitude (volts) higher than the LL discriminator and lower than the UL discriminator to continue on to be registered or counted by the scaler. The heights of the LL and UL discriminators may be input manually when setting up a computer-controlled counting protocol. The settings of both the LL and UL discriminators can be used to define a counting region or counting window. The LL discriminator can be used to eliminate electronic noise pulses, which will be a function of the photomultiplier cathode to anode voltage setting ( Pujol et al., 2000). These are the lower level (LL) and the upper level (UL) discriminators. In general, there are two discriminators, which are used to identify the pulses, which may continue on to be registered. A pulse height discriminator is an electronic gate that permits pulses of a certain magnitude to continue on in the circuit to be registered and counted. Subsequent to amplification and pulse shaping, pulse height discriminators come into play. L'ANNUNZIATA, in Handbook of Radioactivity Analysis (Second Edition), 2003 C. It is possible to generate triangular and square pulses using this method. In this scheme, a first chirped grating is used as a pulse shaper and the second as the dispersion compensator. Cascaded gratings with different dispersion characteristics can thus be used for pulse shaping using a system similar to the one shown in Fig. Other applications include performing mathematical functions such as differentiation.

#ADVANTAGES OF OPTISYSTEM CODE#

Pulse shaping has been demonstrated by several researchers using a number of different schemes, such as spectral encoding for code division multiplexing (CDMA), real time spectral analysis, dispersion-less variable band-pass filtering, synthesis of pulses, and manipulating ps pulses. In the demonstration, a ps pulse reflected off a grating was shown to acquire a different form as a result of the dispersion in the grating.

Pulse shaping by chirped FBGs was first investigated by Rotwitt et al.

Raman Kashyap, in Fiber Bragg Gratings (Second Edition), 2010 7.6.3 Pulse Shaping with Chirped Gratings

Advantages of optisystem