Abstract: The disclosed optical data link provides full-duplex, high-data rate optical communications between geographically separate data processing facilities by means of identical optical transceivers. Transmitter optics include an LED and a collimating Fresnel lens for providing a collimated, modulated light beam. Receiver optics include a focusing Fresnel lens and a photoreceptor for converting the impinging modulated light beam into corresponding electrical signals, which are amplified by a gain-controlled amplifier. The LED is selectively translatable along its optical axis to provide focal length correction for temperature-induced focal length distortion, while the photoreceptor is selectively translatable along its optical axis to provide, in addition to focal length correction, a preselected amount of optical energy attenuation.

Abstract: A peak detecting network utilizes a passive integrating filter to translate the peaks of an input signal into zero crossings of a translation signal, while providing a high degree of noise rejection and preventing the build-up of a DC component in the translation signal. The peak detecting network includes a sine pulse-forming filter comprised of a parallel cascade of a DC shunt inductor, a plurality of series LC sections, and a terminating capacitor. The series LC sections are characterized by respective transfer functions whose impulse responses are substantially finite time duration sine pulses of a successive number of cycles. A rectifier network applies a rectified input signal to the sine pulse-forming filter. A buffer network taps the response of the LC section associated with a one-cycle sine pulse impulse response. The resulting translation signal has a positive-going zero crossing corresponding in time to the occurrence of a peak of the rectified input signal.