Abstract:
A method of and system for estimating the bit error rate of a channel in an optical communication system includes a method of and system for measuring the in-band cross-talk of the channel in a wavelength division multiplexed system. A single channel is selected from the plurality of channels in the optical communication system. The signal in this single channel is passed to a digital signal processor proportional to the time rate of change of a phase of an optical source generating the signal. The digital signal processor converts the filtered signal into the frequency domain, and a spectrum analyzer determines the features of the in-band cross-talk from the signal in the frequency domain. The features of the in-band cross-talk may be combined with other measured noise features, such as the power spectral density, to estimate BER.
Abstract:
A method of and system for estimating the bit error rate of a channel in an optical communication system includes a method of and system for measuring the in-band cross-talk of the channel in a wavelength division multiplexed system. A single channel is selected from the plurality of channels in the optical communication system. The signal in this single channel is passed to a digital signal processor proportional to the time rate of change of a phase of an optical source generating the signal. The digital signal processor converts the filtered signal into the frequency domain, and a spectrum analyzer determines the features of the in-band cross-talk from the signal in the frequency domain. The features of the in-band cross-talk may be combined with other measured noise features, such as the power spectral density, to estimate BER.
Abstract:
A touch system for sensing a touch event that includes a transparent sheet having opposite upper and lower surfaces and an index of refraction n 2 . The system also has at least one light source that emits light. The light source is operably arranged in optical communication with the transparent sheet to cause the light to travel within the transparent sheet by total-internal reflection (TIR). At least one detector is operably arranged to detect the TIR-traveling light and to detect an amount of attenuation in the TIR-traveling light caused by the touch event. An interface layer is disposed on the lower surface of the transparent sheet. The interface layer has a refractive index n 1 , wherein n 1 2 , and has a thickness of equal to or greater than 1 micron. The interface layer obviates the need for an air gap when interfacing the touch system to a display unit of display device.