Abstract: An automatic, multi-use device for measuring the transfer function of any nonlinear continuous network or network component. Transfer functions (also known as input/output reactions) are the main characteristics of all communication and information processing systems. Their evaluation, in the general case, is an elaborate problem. The conventional evaluation procedure had been to linearize the problem, but this procedure was inaccurate in principle and time-consuming. The method of the invention includes the steps of measuring a set of harmonics resulting from application of one (or two) single-frequency sinusoidal signal(s) to the network of interest, and then processing the measured data. The measurement operation is extremely simple. For most networks, only a small number of harmonics of the network's response to a single sinusoidal input signal need be measured.

Abstract: A method and apparatus for registering an image using coherent radiation. Spatial homodyne means are employed to generate component signals which comprise a homodyne equivalent of the image, and the component signals of the homodyne equivalent are registered at a registering medium. Using a new principle of construction, the invention achieves on standard registering media a substantial improvement in conrast resolution. Indeed, the number of contrast levels that can be registerd by the invention is the square of the number that can be registered by the prior art. The application of temporal submodulation in a device embodying the invention additionally provides tensor parasitic phase-shift invariance.

Abstract: A keyless holographic locking device that uses a matched optical filter to store in form of a hologram a unique identificaton such as a fingerprint of an authorized user, a source of coherent light that provides the illumination, and an input element for providing angle-invariance possessing the form of a transparent window against which the user places and rotates the same fingerprint, and a registering device for registering the correlation optical signal between the stored fingerprint and the presented fingerprint to generate a signal to unlock the device when, and only if, a positive correlation exists between the presented and the stored fingerprints.

Abstract: An inexpensive wallpaper, which may be plastic and self adhesive. Using the positive features and advantages of thin-layer holograms and other existing technology, the claimed invention produces a changing, moving or stable 3-D effect in the presence of a low-powered laser illuminating system. In usual (incoherent) light, the claimed wallpaper reflects light as does a standard wallpaper. On the claimed wallpaper, images of any kind can be additionally printed without damaging the coherent 3-D reconstruction. The claimed wallpaper produces 3-D images, whose qualities are not affected by mechanical damage of any kind, including scratching or scraping, and it can also be produced in a washable embodiment. The suggested object incorporates recognized computer techniques, by which an image of any level of complexity can be included. The wallpaper can be printed on plastic or other media by sequentially applying a pre-prepared small-area matrix.