Abstract: A split phase delay equalizer is provided which reduces loss without resorting to high values of load impedance. The equalizer has a pair of parallel circuit branches, one of which is through the base and collector of a transistor, and the other through a reactance network connected between the collector and base of the transistor.

Abstract: A prescription attenuator comprising a plurality of cascaded L-pad sections coupled together to form an attenuator network wherein each cascaded section includes a single pole switch for activating its respective section. The network impedance values are selected so that single L-pad section activations produce actual attenuations slightly more than an ideal level of attenuation wherein multiple section activations tend to keep the error evenly distributed about the ideal level of attenuation.

Abstract: A split phase delay equalizer is constructed using a single transformer. An adjustment for Q loss is provided by a flat loss shift in the amplitude response of the equalizer down to a level at or below the lowest Q loss dip level.

Abstract: Stray reactance compensation is provided in a split phase delay equalizer by inserting an auxiliary compensating small reactance in the substantially real arm circuit branch which provides a third order response equal and opposite to the deviation from second to third order in the amplitude response curve caused by stray reactance deviated phase reversal from the ideal.

Abstract: An error checking circuit is provided for a digital transmission system having a dual, redundant, bus structure. The error checking circuit generates a two rail logic output having complementary states in the absence of an error, and non-complementary states in response to an error on the buses. The circuit is also self-checking in that internal failures are transmitted to the output as an error indication. The circuit is actively exercised in the absence of an error to prevent silent failures. The circuit can identify which of the buses has failed, for the most common types of failures.

Abstract: A phase locked loop (10) has a phase insensitive frequency comparator (18) including an up/down counter (26) incremented one way by loop frequency pulses (on 28) and incremented the other way by reference frequency pulses (on 30) and which yields error correction signals (on 22 and 24) to adjust loop frequency when the counter overflows or underflows given limits. Timing means (32) is provided at the input (28, 30) to the counter (26) and prevents any clock pulse from being lost by ensuring a sufficient time gap between pulses. A sample and hold phase detector circuit (16) is provided at the data acquisition input to the loop (10) and enables successful acquisition and lock-on even with many zeros between the incoming data bits, and does so with a minimum number of components.

Abstract: A servo mechanism is illustrated which uses pulse pairs for positioning a motor by a given increment with a velocity sensing sample and hold feedback utilized to minimize detrimental repositioning forces. The velocity sensing is accomplished after the end of the drive pulses since this sensed voltage is proportional to the magnitude of the detrimental repositioning forces.

Abstract: Magnetic field detection apparatus including means for supplying a periodic excitation signal to a rod of magnetic material having high permeability (whether or not it has hysteresis due to retentivity of the core or eddy currents) and means for sensing the external field wherein the material is situated. When the material has retentive properties and there is an external field being detected the flux lag (or lead) relative to the periodic excitation is longer for one flux direction that the other. The difference in these lags provides an indication of the field to be detected. When the material does not have retentive properties, an external field can still be detected by logic circuitry in an embodiment similar to the last mentioned embodiment.

Abstract: An integrator is illustrated which provides normal action integration operation as long as the input signals remain a given polarity. However, when the input signal changes in polarity, the integrating capacitor is substantially instantly discharged and then the integrator integrates, from the discharged capacitor condition, in the changed polarity direction until the input signal polarity again changes.

Abstract: Circuitry is disclosed for detecting signal amplitudes of a signal which is phase indicative of a digital logic level and providing a feedback signal for use in amplitude adjusting the signal to have a substantially zero slope over the relevant frequency bandwidth and zero notch in the middle of the band. The compensation is obtained by applying a voltage to variable impedance pin diodes which form part of a reactive load circuit.

Abstract: A magnetic field sensor is illustrated which in one useful application comprised two orthogonally positioned coils each having its own electronics and each wound on separate small strips of core material and positioned in a gimballed fixture for use as an electronic compass. The sensing coils in each sensor sense only the components of magnetic field in that plane with one output being representative of the field along the axis of one of the coils and the other being representative of the field along the axis of the other coil. A secondary winding cooperating with each of these coils provides an output signal which is operated upon to remove any DC components and provide a signal indicative in waveshape of the flux in the core. Opposite polarity peak detectors are then used to determine the relative peak voltages with respect to ground for the purpose of determining the DC component which had been removed. The DC component is indicative of any external fields affecting the flux levels in the core material.

Abstract: A rod of magnetic material which has a very small diameter compared to its length is used in combination with a drive and output winding wound around the circumference of the core rod to provide the sensor for measuring magnetic field strength. The rod is periodically and cyclically driven to saturation in each direction by a triangular waveform drive signal generator. A point on the saturation curve in each direction of saturation is picked and the relative time between these points for a no external field condition is determined. Any deviation from this no external field condition is sensed and applied to an integrator which provides both the output signal and a feedback signal which is used in combination with the signal generator to compensate for effects of the external field on the saturation points in the sensor. When the output signal is representative of the magnetic field, there is again no deviation in the time of occurrence of saturation in the rod from the no external field condition.

Abstract: The present invention uses two interconnected baluns with the balanced output of one feeding a balanced input of the other. When this filter is used in conjunction with a signal frequency converter, the balun pair not only provides extremely effective bandpass filtering so as to pass the RF frequencies and not the IF frequencies but, in addition, provides a condition which appears to the IF as a nearly open circuit and thus provides a large amount of reflection or return of the IF signals to the signal converter so that the overall signal converter operation is more efficient in combination with the present invention than with any comparable known prior art signal isolating device.

Abstract: A magnetic field sensing device comprising a magnetic rod which is direction sensitive relative to the field being measured. The rod is of such design that the magnitude or the strength of the field being sensed, significantly affects the magnitude of the excitation field required to produce a saturation of the magnetic core. An external field in the longitude direction of the core will require that the excitation field magnitude required to produce a given level of saturation will be different in one direction than in the other, by magnitude equal to twice the component of the external field acting upon the core. The excitation field is produced by current in the winding with the current changing at a given rate so that the induced or output voltage is greater than a specified value; as long as the core permeability is greater than a given specified value.

Abstract: A magnetic field directional magnetic sensor wherein the magnetic material has a large length-to-diameter ratio and comprises two coils wound around the magnetic material which also have a small diameter compared to the length. A first coil is driven with a triangular waveform signal. After each occurrence of saturation, a voltage will be produced by the output coil. The voltage amplitude of the drive signal can be measured upon the occurrence of each of the output pulses from the second coil with the measuring or detection of the drive signal being used in a sample and hold circuit which averages the detected values for a determination of magnetic field being sensed in the longitudinal or long direction of the magnetic sensor.

Abstract: Circuitry is disclosed for detecting signal amplitudes of a signal which is phase indicative of a digital logic level and providing a feedback signal for use in amplitude adjusting the signal to have a substantially zero slope over the relevant frequency bandwidth. The compensation is obtained by applying a voltage to variable impedance pin diodes which form part of a reactive load circuit.

Abstract: A voltage dividing and reference circuit for creating a pseudoground from a unipolar power supply such that when used in combination with a digital voltmeter circuit a bipolar input signal can be measured for both polarities with respect to ground.

Abstract: Circuitry for detecting the spectral distribution of a signal that is phase indicative of a digital logic level and providing feedback signals for use in adjusting the amplitude of the signal spectrum to reduce signal distortion toward a value which is substantially identical with the transmitted signal for all points over a given frequency bandwidth. The correction is obtained by applying voltages to variable impedance pin diodes forming part of a series set of tuned filter circuits.

Abstract: Circuitry for detecting the spectral distribution of a signal that is phase indicative of a digital logic level and providing feedback signals for use in adjusting the signal amplitude of the spectrum to have a substantially zero slope over the relevant frequency bandwith. The correction is obtained by applying voltages to variable impedance pin diodes forming part of a tuned filter circuit.

Abstract: The present invention uses two interconnected baluns with the balanced output of one feeding a balanced input of the other. When this filter is used in conjunction with a signal frequency converter, the balun pair not only provides extremely effective bandpass filtering so as to pass the RF frequencies and not the IF frequencies but, in addition, provides a condition which appears to the IF as a nearly open circuit and thus provides a large amount of reflection or return of the IF signals to the signal converter. Through the use of additional grounding stubs, additional coupling means, increased separation between coupling means and separated ground planes each singularly or in combination, improved performance has been obtained as compared to the prior art.