Atlantic Sciences
EnvCalc Features 
Features of the EnvCalc toolboxEnvCalc is a toolbox of routines running under MATLAB® that processes waveforms from a realtime sampling oscilloscope. Starting from saved raw measurement files, it calculates the information bits on the optical signal, together with the bit error rate and Q factor, and can display the signal graphically in a multitude of ways.
The EnvCalc toolbox can be put to use quickly by anyone with moderate knowledge of MATLAB. · Builtin help text for each routineHelp text includes explanation of the function, plus details of all input and output parameters · Comprehensive error checkingError messages and warning messages to catch inadvertent coding mistakes by the user, each providing advice on which parameters to correct.
EnvCalc includes the following functions: · Calibration of the passive optical mixerDetermines phase angle and path length difference between outputs of hybrid. · Clock recoveryFinds clock for binary & quaternary formats, including the case when clock frequency is not related to sampling rate by a rational multiplier. Retimes signal to give a sequence of complex values corresponding to symbol centres. Processes signal seamlessly in blocks to avoid memory overflow when measurement burst is long. · Phase estimationRecovers the optical phase of the signal and applies phase correction. Phase estimate is near theoretical limit in terms of tolerance to phase noise – works with DFB lasers. · Match signal values to pseudorandom bit sequencePRBS recovery works in presence of bit errors & cycle slips. Support for wide range of pseudorandom sequences, including all standard sequences. · Count bit errorsCounts errors for binary and quaternary formats. Separates bit errors from cycle slips, and reports them independently. · QfactorCalculates decision threshold Qfactor or simple (histogram based) Qfactor. · Adaptive equalisationCan be used to set filter coefficients to optimise a given parameter, e.g. Qfactor, to obtain best possible receiver frequency response.
· Graphical outputProduces several graphical representations of measured data: phase diagram, eye diagram, etc.
EnvCalc will run on a Macintosh, PC or workstation, provided MATLAB is already installed. For more information click here.
