Abstract: In a solar water system including a solar collector prevention of damage to the collector during freezing conditions is achieved by providing a relatively small independent heat exchanger between the solar collector and the water heater and a vacuum breaking system whereby the water in the solar collector is drained into the heat exchanger. The heat exchanger is connected to a thermal siphon arrangement with the water heater.

Abstract: A continuously variable flat belt pulley transmission, using integral rotary actuators, is described together with controls to vary the transmission speed ratio upon demand and simultaneously operate an internal combustion engine or electric motor on a desired torque versus speed schedule.

Abstract: The disclosure teaches a painter's protective device providing a mask adapted to cover the forehead, eyes and nose of the wearer and having suitable eye holes and a visor projecting outwardly from the forehead portion of the mask above the eye holes and means for retaining the mask on the wearer's head. In a preferred embodiment the eye holes are covered by a screen.

Abstract: Apparatus for intermittent delivery of a fluid under pressure wherein a plunger having a conduit is disposed in a housing for reciprocal, rotary motion and responsive to fluid pressure at the intake end, by means provided in the plunger pops out of the housing and rotates a pre-selected number of degrees. Means are provided to stop both rotary and axial movement simultaneously.

Abstract: An improved antenna system is disclosed in which a single antenna array is simultaneously used in conjunction with several independent radio devices. Isolated and independent radio transmitters are coupled, without any signal cancellation, to each and every one of a plurality of isolated independent antenna elements by a combining network which maintains the isolation between each of the radio transmitters and each of the antenna elements. The combining network comprises an array of hybrid networks and creates a predetermined electrical phase difference between each signal received by an individual antenna element. The antenna elements form a single antenna array consisting of circularly disposed corner reflector antennas. Each reflector independently creates an individual radiation pattern and these patterns combine to form a single desired composite radiation pattern.

Abstract: A signal at a frequency f.sub.0 is coupled through matching circuitry to the input of a parametric frequency multiplier stage. Non-linearities in this stage generate harmonics of the frequency f.sub.0, including a desired harmonic k.times.f.sub.0, where k=2, 4, 6, 8... . Unique output coupling circuitry presents a high load impedance to the parametric multiplier at the frequency f.sub.0, thereby enhancing harmonic generation, and transforms the impedance to signals of frequency k.times.f.sub.0 at the multiplier stage output to a desired value. The output coupling circuit includes two series connected transmission lines which couple between the output of the parametric multiplier stage and the multiplier output. A third transmission line, having an electrical length of one quarter wavelength at frequency f.sub.0, is connected as an open circuit shunt stub to the multiplier output, thereby effectively producing a short circuit thereat at f.sub.0.

Abstract: A vibratory feeder device has a forward moving mechanism and recirculating, or return, mechanism side by side and separately and independently controllable. The forward feeding mechanism has a feeder track that includes an angularly sloping surface down which devices to be fed, such as transistor chips, slide under the influence of gravity into the return chute unless caught by the terminals of the fed devices. The angularly sloping surface has a groove in the feed direction in which the terminals become engaged. If the device's terminals are engaged by the groove so that they are in the proper attitude, the devices are fed along under the vibratory feed forces. If not, they are brushed off onto the angularly sloping surface by a blade or fall through a hole adjacent a deflector. In either case the rejected devices are returned to the supply hopper.

Abstract: The presence of a tone in a received signal is detected by passing the signal through a bandpass filter tuned to the frequency of interest. The output from the filter is peak detected and applied both to the first input of a comparator and to a unique variable threshold circuit which, in turn, is coupled to the remaining comparator input. The threshold circuit tracks the peak detected level of the bandpass filter output such that the comparator is activated between its logic states, representing the detect or undetect condition, with a minimum of delay time.

Abstract: Each of a plurality of antenna sectors is sequentially coupled to a receiver via an antenna switch. The switch is operated by control logic circuitry which monitors the peak signal levels of the signals received by each sector. Unique circuitry is implemented which prevents the control logic from responding to spurious transient signals processed by the receiver's tuned circuits following each instance of antenna switching.

Abstract: An RF power transistor device, or package, which includes a transistor, a capacitor, an electrically insulating but thermally conducting substrate, a metallic ground lead member on the substrate having input output and common portions, a heat sink on which the substrate is mounted and, input and output microstrip conductor means mounted on the heat sink has the common lead inductive effect of at least one component of common lead inductance of the transistor reduced by tightly coupling the input ground current and the input current as by a film of dielectric material such as Kapton or Teflon of about one half mil in thickness. Alternatively the output current and the output ground current may be tightly coupled.

Abstract: A digital voice privacy electronic communication system and method provides protection for an information signal. Either a clear voice signal or a scrambled digitized version of the voice signal is selected for transmission. At the receive end of the system a determination that a clear voice signal or a scrambled signal has been sent is made. This information is used to automatically switch the clear audio signal if present to an output circuit or to switch to the output circuit either a regenerated version of the scrambled signal or an unscrambled version of the information signal. The switching is done automatically so that a user does not have to manually select the proper receiver mode in response to reception of a signal, that is, whether the received signal was a clear voice signal or a scrambled signal. At the transmitter the information signal to be scrambled is analog-to-digital converted and the digital signal is then put into a scrambled form.

Abstract: A surface acoustic wave device wherein the interdigitated fingers are capacitively weighted with decreasing capacitance from the center of the transducer to the ends thereof has an improved response in the frequency passband in that the dip therein is substantially diminished, if not eliminated, when the interdigitated fingers of the transducer are of the split-connected form except adjacent at the ends of the transducer where the interdigitated fingers are of the split-isolated form, or all of the interdigitated fingers are of the split-isolated form. The increased surface acoustic wave reflection occurring at the end fingers where the weighting capacitors are small is overcome by the decreased surface acoustic wave reflection resulting from the increased impedance of the split-isolated fingers.

Abstract: An improved electronic watch module structure includes a chassis member having an egg-crate configuration. A substrate having electronic watch components and conductors mounted thereupon has a piezoelectric crystal elememt mounted on it. The substrate is contained by the chassis member. A portion projecting from one of the side walls of the chassis contains a cavity, and the cavity and a portion of the substrate integrally form a hermetically sealed chamber for the piezoelectric crystal element.

Abstract: The encoder processes M information characters, each of bit length m, followed by k-1 flush out bits, through an (n,k) convolutional encoder. Each resulting output character is stored as one row of an output register matrix. A transmission bit stream is formed by extracting bits from the register on a column by column basis, thereby interleaving the characters.The decoder fills an input storage basis on a column by column basis, thereby restoring each character in its appropriate row. The characters are sequentially switched to an (n,k) convolutional decoder which outputs the original m bit information character. The characters are, in turn, stored in corresponding rows of an output register matrix, where they are available as recovered data.

Abstract: A system, including an encoder and decoder, for the transmission of digital information over a transmission medium. The encoder processes a data stream of length M and generates a transmission bit stream. The processing includes combination of the M data bits with N predetermined sync bits, via a modulo-2 adder. The resulting transmission stream has a total length less than M+N, thereby substantially minimizing the number of bits otherwise required.The decoder regenerates the data bit stream by modulo-2 subtraction of the transmission bit stream with said N sync bits, stored within the decoder.The resulting system thereby provides optimum synchronization and, therefore, data recovery, while requiring a minimum of transmission bits.

Abstract: The pre-limited IF signal from an FM receiver is coupled to a pair of linear amplifiers in a cascade configuration. The outputs from the amplifiers are detected and passed to piecewise linear amplifiers. Each piecewise linear amplifier is designed to exhibit a gain characteristic which is dependent on the level of signals applied at its input. A summing circuit sums the piecewise linear amplified signals in predetermined proportion to thereby produce a DC signal which is linearly related to the receiver's quieting level.

Abstract: The inventive synchronization circuit accepts a reference input signal and produces a signal which is in both phase and frequency lock therewith. The reference signal is quadrature detected via a voltage controlled oscillator signal, a quadrature phase shifter and a pair of mixers. A frequency error signal is generated by processing the mixer outputs through a phase detector and integrator. A phase error signal is produced by extracting and combining the DC components of the signals at the mixer outputs. The frequency and phase error signals are summed to produce a control signal which is fed back to the voltage controlled oscillator, thus causing the oscillator signal to tend to lock in frequency and phase with the input reference signal.

Abstract: Three electrode pairs are formed on a monolithic piezoelectric element which exhibits anisotropic properties with respect to its X and Z axes. The electrodes of each pair are located on opposite sides of the piezoelectric element, with all electrodes being of predetermined dimensions. The first and second electrode pairs are aligned on the X axes at a predetermined spacing therebetween. The second and third electrode pair are aligned on the Z axis, also at a predetermined spacing.In circuit operation, a signal to be processed is coupled to the first electrode pair and extracted from the third electrode pair, with the electrodes of the second pair shorted together. In this manner, the resonator displays a three pole passband characteristic having excellent spur suppression.

Abstract: A receiver produced signal includes an information signal immediately preceded and followed by noise signals. The presence of an information signal is sensed by detector circuitry which, after an inherent delay interval, closes a squelch gate. The detector experiences an additional delay at the conclusion of an information signal.To prevent both deletion of the initial portion of the information signal and a noise "tail" following said signal, a delay line, comprised of a bucket brigade device, is series coupled between the receiver and the squelch gate. The delay provided by the delay line is approximately equal to the inherent delay time of the detector means.

Abstract: A piezoelectric monolithic crystal filter operating in the trapped energy mode and having a capacitor plated on the piezoelectric wafer within energy coupling distance of the main electrodes has its output response improved by trapping wave energy, at the frequencies of the main electrodes, engendered by the capacitor and conducting such energy to the edges of the piezoelectric wafer where it is dissipated. Such energy is therefore not coupled into the filter structure and does not appear as an undesirable response.