Abstract: A vent assembly has a vent housing having a first axial end, a second axial end, and an airflow pathway extending from the first end towards the second end. An environmental opening is towards the second axial end for fluid communication with an external environment. An enclosure opening is towards the first axial end for fluid communication with an interior of an enclosure. A perimetric support surface surrounds the airflow pathway. A support brace extends across the airflow pathway. The support brace has a lateral support surface offset in the axial direction from at least a portion of the perimetric support surface. Filter media is disposed laterally across the airflow pathway. The filter media has a perimeter region supported by the perimetric support surface around the airflow pathway and a central region supported by the lateral support surface such that the filter media is non-planar.

Abstract: A digital TV receiver having an analog-to-digital converter which generates digital representations of the analog signal asynchronously relative to the color burst reference, includes open loop circuitry for correcting the values of the chrominance component to comport with chrominance samples having a fixed phase relationship with burst. During the burst interval the angle of the chrominance phasor relative to the asynchronous sampling instants is compared with a fixed angular reference value to generate a correction factor for the respective line of video signal. The correction factor is thereafter combined with the chrominance samples to generate new chrominance samples having a desired phase relationship with the phase of the burst reference signal.

Abstract: A video FM transmission system includes a transmitter coupled to a receiver by means of an FM transmission path subject to triangular noise effects. The receiver includes a coring circuit for reducing the noise and the transmitter includes a coring compensation circuit having a transfer function different from and not complementary to the transfer function of the coring circuit. The transfer functions are selected so as to effect greater coring of the triangular noise characteristic of the FM transmission system and lesser coring of the desired small-signal high-frequency components of the video signal thereby providing a desired signal-to-noise ratio enhancement of the video. In preferred embodiments of the invention the transfer functions of both the coring circuit and the coring compensation circuit are provided by programmed read only memories having different and non-complementary programs.

Abstract: The individual red, green, and blue video white levels from a color television camera are maintained constant when the individual red, green, and blue black camera control levels are adjusted by the master black camera control by additively summing a first percentage of the selected master black level to the individual red, green, and blue black levels to form the final individual black levels and by subtracting a second percentage of the selected master black level from the individual red, green, and blue white levels selected by the individual red, green, and blue white level camera controls.