An apparatus for monitoring air pollution sources, such as, for example nitrous oxide (NO), sulphur dioxide (SO.sub.2), or sulphur trioxide (SO.sub.3) is disclosed. The apparatus includes a tunable diode laser as a transmitter of infrared energy. The diode laser is tuned in a periodic fashion such that the laser light emission wavelength is scanned through an absorption line of a pollutant gas. The tuning effect is produced by driving the diode laser with a current which is the sum of a d.c. and...

A digital system is disclosed for conversion of data rates inherent in various scanning patterns to different rates for display. A buffer memory is employed to accumulate blocks of data pertaining to successive scanning lines in a rectilinear or polar coordinate scanning pattern. The data is transferred in blocks to a bulk storage memory from which it is read cyclically for display. Different scanning and display patterns are accommodated through mode control switches. In multi-bar-elevation rad...

The invention relates to a mode selector having a plate showing an electro-optical effect in an electric field to control the modes of oscillation in a scan laser. The new mode selector consists of two identical selectors which are rotated relative to each other through 90.degree. and which are each arranged in a focal plane of the laser-resonator and of which one controls the x coordinate and the other controls the y coordinate of the focus, in which a plate-shaped electro-optical KDP material ...

A video magnetic disk is utilized in the conversion of side looking sonar or slow scan TV data into a form suitable for displaying as a flicker-free picture on a conventional TV monitor. In the side looking sonar mode of operation, provision is made for displaying the sonar information as a moving window display.

There is disclosed a visual scan converter which accepts digitalized video data available from a source such as a radar receiver in any given scan pattern such as a PPI format at slow radar rates and converts the data format to make it suitable for presentation on a cathode ray tube in a standard television or other orthogonal raster at flicker free rates. Greater flexibility and economy than has heretofor been available in digital scan converters is achieved by using a random access memory. Con...

A circuit device for use in a multi-line rate image reproducing assembly such as, for example, a video monitor is disclosed herein. The device, which permits changing the line rate of the assembly without changing the horizontal dimensions of the reproduced image and which in normal operation requires only a single adjustment control for acheiving this end, includes circuitry connected with the adjustment control and responsive to a selected voltage level supplied from a source for producing, ac...

In an electronic scan modular antenna system operating at frequency F, a circuit supplies the n modules (where n is an integer) forming the antenna with n respective synchronization signals. The circuit comprises wave generating means supplying two component signals in phase quadrature in respect of each other, of frequency f= F/p (where p is an integer), respective means varying respectively the amplitudes of said component signals as functions of the desired direction of radiation of the anten...

An elongated horizontally disposed waveguide has a series of holes in one longitudinal side wall dimensioned below cut-off so as to be non-resonant and insensitive to wave length variations. The dimensioning and spacing of the holes on the one longitudinal side wall provides for radiation of a fan shaped beam in a vertical plane having a fairly broad elevational angle and an extremely narrow azimuth angle. The fan shaped beam itself is caused to scan through a given angle in azimuth by means of ...

A digital facsimile scanning system in which transitions in alternate lines are shifted by sub-multiple clock pulse intervals. The sampling time, i.e. the time for sampling either black or white information bits is staggered on every two or more sweeps, to reduce the occurence of clouded patterns and to give an appearance of increased resolution.

A vertical scan circuit for a television receiver in which a free-running oscillator is synchronized by the vertical synchronizing component of the received signal. The free-running frequency of the vertical oscillator is varied in accordance with the amplitude of the received television signal.