Abstract: A system is provided by which a single active video signal, along with a plurality of audio and data streams can be made to represent a number of different screens of information at a cable TV set. The system uses essentially only the bandwidth of a single video channel to provide a viewer with a plurality of screens, one or more of which include the same active video picture, simultaneously with other screens which display only audio and text/graphics. This multiple-screen capability is provided by a mapping function which creates an effective plurality of channels that are dynamically and seamlessly switched.

Abstract: An electronically tunable solid-state microwave frequency source comprises a transmission-absorption filter incorporated within a magnetic structure. The transmission-absorption filter is employed with a tunable solid-state oscillator and tunable solid-state multiplier to provide a continuously tunable microwave signal source with enhanced spurious signal attenuation over a multiple-octave tuning range. The filter structure comprises a sphere of monocrystalline garnet such as yttrium iron garnet (YIG) and two coupling loops disposed in the field region of an adjustable field DC magnet. The coupling loops are disposed orthogonal to the magnetic field and to each other. In a specific embodiment the first coupling loop is operative to receive at its input the fundamental frequency signal and at its output is grounded, and the second coupling loop is operative to receive a harmonic input signal at its input and to convey a desired output signal at its output.

Abstract: A solid-state microwave signal amplifying and multiplying apparatus capable of substantially continuous tuning over an extended frequency range in the microwave region. A single gallium arsenide metal semiconductor field-effect transistor (MESFET) is switchably coupled by means of PIN diodes through selected output matching networks consisting of relatively narrowband frequency sections. Bias to the MESFET is provided through PIN diodes in a manner to select a linear (fundamental frequency) or nonlinear (multiplied frequency) operating region. In this manner a single microwave active device may be utilized with a plurality of passive networks to achieve extremely wideband amplification meeting good amplification and impedance matching criteria.