Abstract: A digital-to-synchro converter is provided where a binary input code specifies a desired shaft angle and where an resolver type position transducer is employed with additional circuitry to generate a shaft position error signal indicative of the angular difference between the desired shaft angle and the actual shaft angle. The additional circuitry corrects for known and calculated errors in the shaft position detection process and equipment.

Abstract: A method and apparatus for determining the orientation of the optical axis of radiometer instruments mounted on a satellite involves a star sensing technique. The technique makes use of a servo system to orient the scan mirror of the radiometer into the path of a sufficiently bright star such that motion of the satellite will cause the star's light to impinge on the scan mirror and then the visible light detectors of the radiometer. The light impinging on the detectors is converted to an electronic signal whereby, knowing the position of the star relative to appropriate earth coordinates and the time of transition of the star image through the detector array, the orientation of the optical axis of the instrument relative to earth coordinates can be accurately determined.

Abstract: A digital tone squelch detect circuit functions to give an enabling signal for audio transmission in an FM radio network. The circuit comprises an analog to digital converter which outputs a binary coded signal representative of the voltage level of a received audio tone signal. The binary signal is then placed into a shift register which periodically is rotated and multiplied by a reference clock signal for correlation with a stored replica of the tone. The output of the correlator, which is representative of the degree of correlation, is fed to an accumulator which integrates it and sends it to a comparator where its binary valve is compared to an arbitrary threshold binary value by a hysteresis network. After detection the hysteresis established circuit outputs a tone detect signal and lowers the detection threshold so as to maintain the tone detect signal during periods of signal fadeout.

Abstract: There is disclosed a Zero IF modulator apparatus for modulating carrier signals with baseband signals, the modulator includes digital logic circuitry including a sine/cosine amplitude converter which is responsive to the baseband signals for providing first and second digital quadrature baseband signals. These digital quadrature baseband signals are then employed by coupling the same to digital-to-analog converters where the outputs of each converter is indicative of a first and second quadrature signal. These signals can then be translated to a given carrier signal for transmission over a desired communication channel.

Abstract: Apparatus for measuring the modulus of elasticity of a sample specimen of a given thickness and area includes means for mounting one surface of the specimen on a rigid reference plane and an opposing surface of the specimen is then mounted on a rotatable surface. A torque arm coupled to the rotatable surface applies a predetermined torque which effectively causes this surface to rotate thereby twisting the specimen through a given angle. The angle is measured by means coupled to the rotatable surface, and based on the measured angle, one can calculate the modulus of elasticity in regard to the measured angle and in regard to the applied torque. The apparatus and methods essentially measure the modulus of elasticity through angular displacement of the specimen.

Abstract: There is disclosed an improved double detection receiver for detecting pulsed RF carrier signals. The receiver employs first and second channels with the first channel being a narrower band than the second channel. Each channel is associated with signal detection circuit to provide first and second detected output pulses. These pulses are summed or substracted to provide an output pulse indicating the sum or difference of each channel signal and this output pulse is appplied to a frequency comparator. One of the detected signals is also applied to a signal strength comparator whose output is gated via gating circuit with the output of the frequency comparator to provide a pulse present output for the presence of both input signals at said gating circuit. The use of the frequency comparators assures improved operation of the double detection receiver.

Abstract: A magnetostatic wave device unit in which the magnetic biasing unit includes a carrier member which contains one of the pole pieces and forms an enlarged mechanical and electrical support surface for a magnetostatic wave device.