Abstract: In a power converter having a resonant output circuit transformer coupled to a load circuit, a transformer coupling circuit comprises at least two transformers providing a coupling stage having inductively coupled windings that are in step down relationship to an input and/or output winding of the transformer coupling circuit. This enables the rate of change of voltage in the coupling stage to be reduced and thus correspondingly reduces the transmission of interference from the power converter to the load circuit.

Abstract: A hybrid frequency shift keying modulator and method produces binary FSK by simultaneously applying a digital modulating signal to the DDS section of a frequency synthesizer along with a coordinated analog modulating signal as direct frequency modulation of the accompanying PLL section. Low frequency performance is derived from the characteristics of the DDS modulation and the high frequency performance and accurate wave shape reproduction are derived from the modulation of the direct FM section.

Abstract: True RMS power demodulation system and method for a modulated RF signal uses a DC coupled linear amplifier and linearizes the diode detector prior to demodulation. The demodulated signal is proportional to the difference of RF powers such that the network measurement is unaffected by the modulation depth at the power sensor which can be degraded by RF feedthrough or the presence of an interfering signal or noise.

Abstract: A signal generator including a calibration circuit for providing periodic recalibration of the generator, including a reference frequency source for producing a fixed frequency signal. A voltage controlled oscillator (VCO) for producing a variable frequency signal in accordance with a voltage input to the VCO. An adjustable dividing network coupled to the VCO for dividing the variable frequency signal by a particular divider (N) to produce an output signal equal to the variable frequency signal divided by "N". A phase detector coupled to the reference frequency source and the dividing network for producing an error signal in accordance with the difference between the fixed frequency signal and the output signal. A filter coupled to the phase detector for producing an error voltage signal representative of the error signal. A programmable nonvolatile storage for storing a plurality of individual values representative of the plurality of frequency steps from the VCO.

Abstract: Power from an alternating signal having a frequency variable in a wide and relatively high range such as approximately 10 megahertz to 40 gigahertz is indicated by a detector. To calibrate the detector, an alternating signal is introduced from a source to a bridge including a regulating member such as a thermistor. The bridge also receives a direct voltage. The thermistor is maintained at a particular impedance such as 400 ohms, regardless of the power provided by the alternating signal, by varying the magnitude of the direct voltage. The alternating signal, which is regulated in accordance with the dc voltage, is also introduced to the detector. The detector output is introduced to a data processing unit which processes the detector output to indicate the power from the alternating signal. The output from the data processing unit is converted to an analog signal which is combined with the signal from the bridge to produce a resultant signal.

Abstract: A circuit is disclosed that includes a pair of varactors coupled to an input sample circuit and having an appropriate capacitance during the sample strobe of the input to minimize sampling errors. The varactors are combined with a control switch having an output timed to symmetrically reduce the capacitance to a new value, preferably a value approaching the input capacitance of a field effect transistor which is included in the output circuit. In this way, a noise-free voltage and power gain of CT0/CT1 can be reached, where CT0 is the initial value of the capacitance of the sampling circuit and CT1 is the final value of the capacitance of the sampling circuit.

Abstract: A valve for a surf pool having a frame of generally horizontal and vertical members, a leg pivotally attached to the higher horizontal member, a foot at the end of the leg for opening and closing the valve and an actuator mounted on the lower horizontal member for pivoting the leg. The foot may include oblique surfaces for reducing its drag and for enhancing the seal between the foot and a valve throat in response to hydrostatic pressure on the foot.

Abstract: Signal quality in a cable in a particular frequency range is monitored and analyzed without interfering with the cable reception of CATV signals. Carrier signals at a transmitter are modulated with a pair of pass signals separated in time by a television frame period. Preferably before the first pass signal in the pair, a series of digital signals is provided indicating the parameters of a frequency sweep which is initiated upon the occurrence of the second pass signal. These parameters include the sweep start frequency, the sweep frequency bandwidth, the sweep duration and the sweep repetition rate. A frequency sweep according to such parameters is produced when the second pass signal occurs. The modulated carrier signals are transmitted through the cable to a receiver coupled to the cable. The receiver demodulates the carrier signals and processes the series of digital signals to determine the sweep signal parameters.

Abstract: A surfing wave pool assembly has a construction so that a continuous front breaking, surfing wave is established. This permits body surfers or surfboards to surf on the forward edge of this advancing wave for most of the length of a pool. The continuous wave front is established by the rapid discharge of water from an elevated reservoir into the deep end of the pool over a reef. A substantial amount of water in the entire assembly is saved by utilizing an elevated floor in the reservoir and a restricted area conduit from the elevated reservoir to openings at the deep end of the pool. The elevated reservoir establishes a sufficiently high head of water to create a surfing wave, yet the elevated floor and the restricted area conduit means substantially limit the volume of water in the assembly required to create the surfing wave.

Abstract: A decimator of the type having a decimation factor of K, is implemented by a finite impulse response (FIR) filter network of length N. The filter network includes N/K accumulators each of which arithmetically combines samples of an input signal as multiplied by a corresponding set of K network branches, and provides a corresponding output sample. The N/K output samples from the accumulators are provided sequentially at the filter output prior to arrival of the next set of N input signal samples at the filter input.

Abstract: A slide structure for sleds for human occupancy is disclosed, and is designed to have human occupant sleds sliding down into a body of water. The slide structure has a support framework on which a plastic sheet material is provided and a water supply means supplies only a thin film of water to the upper surface of the plastic sheet material. This conserves power and water, yet the thin film provides a very low coefficient of friction, so that the sleds attain a high speed for a quiet, fast, smooth, and more exciting ride, yet with reduced wear on both the slide and sleds.

Abstract: A sine wave to triangle wave convertor, including an amplifier having an input terminal and an output terminal, a sine convertor having an input terminal and an output terminal and for producing a sine wave at the output terminal in accordance with the application of a triangle wave at the input terminal, the output terminal of the amplifier coupled to the input terminal of the sine convertor and the output terminal of the sine convertor coupled to the input terminal of the amplifier, and coupling an input sine wave to the input terminal of the amplifier to produce an output triangle wave at the output terminal of the amplifier.

Abstract: Apparatus and Method for providing images on a photosensitive media is disclosed. The invention provides for the multi-point exposure correction of recorded grey scale hardcopy images which utilizes line by line attenuation of video data in a unique pattern. Also exposure compensation is provided for by decreasing the amplitude of the video signal, on a line by line basis, from a predetermined nominal value which is in the recording cathode ray tube's dynamic range. The invention thus performs its function without compromising the dynamic range of the recording mechanism.

Abstract: A pulse delay compensator for use with a divide counter dividing a frequency signal by a first positive integer or a second positive integer to produce a divided frequency signal and with the first and second positive integers a fixed number of integers apart and including controlling the divide counter to divide the frequency signal by the first or second positive integers, repetitively summing a fixed fractional number with each divide and with the control of the divide counter in accordance with each overflow produced by the repetitive summing, and producing pulse delay compensation for the divided frequency signal in accordance with the repetitive summing to equalize the pulse period between adjacent pulses in the divided frequency signal.

Abstract: A wide band oscillator with phase lock loop is controlled by signals from an 40 MHz harmonics generator combined with the output of another phase lock loop controlled oscillator whose selectible outputs vary in MHz steps with a total range of 39 MHz. The phase lock loop of the wide band oscillator is additionally controlled by a d/a converter and by another phase lock loop controlled oscillator whose selectible outputs vary in one KHz steps. Each of these phase lock loops is digitally controlled from the input frequency selection and again therefrom via a digital-to-analog converter. The output of the wide band oscillator is combined with the output of a narrow band oscillator which may be FM modulated. Alternatively, an output amplifier for the combination difference frequency may be AM modulated.

Abstract: Input signals having a particular impedance in a particular frequency range are provided. A first transformer has at its input a particular impedance in the particular frequency range and provides a change at its output to a second impedance in the particular frequency range. A filter is constructed to receive the signals from the first transformer and is provided with the second impedance in the particular frequency range. When the second impedance is lower than the particular impedance, the operation of the filter at the second impedance is advantageous because the size of the inductances in the filter is significantly reduced without impairing the quality of the inductances or increasing energy losses in the inductances.A second transformer is constructed to receive the signals from the filter. The second transformer provides the second impedance at its input and provides at its output a change to the particular impedance in the particular frequency range.

Abstract: A processing system for heat developed photosensitive recording material or media is provided. This system processes the media with a minimum of waste of recording material. The media is processed at a fixed temperature and for a fixed period of time regardless of the speed at which the media passes through the processor. In one embodiment the system utilizes recirculating air to process the media. The heated air is captured in an oven configuration which employs the media itself as part of the air circulation path.

Abstract: A spectrum analyzer for FFT analyzing and displaying the frequency spectrum of a digital signal over a given frequency band (background), as well as over a more limited frequency band (foreground). The spectrum of the signal over each frequency band is calculated and displayed so as to appear on a screen as a simultaneous display. The position of the limited frequency band as well as the width thereof, may be varied.