Abstract: An antenna unit for measuring the velocity of a flowing material by the Doppler effect is particularly suited for use where only a limited space is available. The antenna unit comprises a support block having first and second surfaces disposed at an acute angle (optimally 45.degree.) relative to each other. A printed circuit antenna card having thereon a high gain antenna comprising a phased array of antenna elements is mounted to the second surface and radiates microwave energy toward the first surface. A plate having an opening therein is disposed adjacent the first surface, the plate being made of a material which absorbs radiated energy incident thereon. The support block is provided with a recess for receiving an absorber wedge which absorbs the energy radiated in near side lobes. The absorber wedge and plate shape the radiation pattern so that energy radiated by the antenna intercepts the material at an angle of 45.degree..+-.15.degree. when the first surface is disposed parallel to the axis of flow.

Abstract: A monitor for monitoring the moisture content of grain comprises at least one programmable PIN diode attenuator connected between a microwave measurement signal source and a transmit antenna. A controller stores an addressable attenuation table, each location in the table storing an attenuation value and an associated attenuator address. A counter accesses the table locations sequentially and the attenuator addresses are applied to the attenuator to cause a step-wise decreasing attenuation of the measurement signal which is then transmitted through the grain. After the signal passes through the grain, it is detected and applied to a threshold comparator. When the magnitude of the detected signal reaches the threshold, the counter is stopped and the attenuation value at the location pointed to by the counter is taken as the attenuation of the measurement due to moisture in the grain. Once the attenuation has been determined, the moisture content and mass grain flow may be calculated.

Abstract: A microwave grain monitor determines grain density and moisture content without measuring the phase shift of the measurement signal in passing through the grain. A set of grain coefficients is determined and stored in a non-volatile memory. A microwave measurement signal is transmitted through the grain and the ambient temperature is sensed. The grain density and moisture content are determined from the attenuation of the measurement signal in passing through the grain, the sensed temperature and the set of grain coefficients.

Abstract: A microwave grain monitor determines grain density and moisture content without measuring the phase shift of the measurement signal in passing through the grain. A set of grain coefficients is determined and stored in a non-volatile memory. A microwave measurement signal is transmitted through the grain and the ambient temperature is sensed. The grain density and moisture content are determined from the attenuation of the measurement signal in passing through the grain, the sensed temperature and the set of grain coefficients.

Abstract: A monitor for measuring the moisture content of grain comprises an AC signal source for transmitting a measurement signal along a measurement signal path that includes a sensor region in which grain may, or may not, be present, and an analyzer for determining the attenuation of the measurement signal along the path, the analyzer producing an indication of the moisture content of grain in the sensor region that is dependent on the attenuation. A simulator is provided to permit calibration, testing, maintenance and/or demonstration of the monitor without the requirement of grain in the sensor region. The simulator includes a programmable attenuator that is selectively electrically inserted in the measurement signal path and a control circuit for controlling the attenuator so that the measurement signal is attenuated and the analyzer produces an indication of grain moisture content even though no grain is present in the sensor region. The attenuator may be a PIN diode or a programmable capacitor.

Abstract: A fixture for use in the microwave measurement of the moisture content of grain comprises a hollow support member, an antenna support assembly supporting antennas for transmitting and receiving microwaves, and a sample scoop. The support member, antenna support assembly and scoop are made of a low dielectric plastic material which has negligible effect on the microwaves. The antenna support assembly includes a cylindrical sleeve with two support stubs extending radially outwardly from the sleeve. The support member has two recesses in its top surface for receiving the stubs so as to position the antenna support assembly and the antennas relative to the support member. The sleeve has an inside diameter slightly greater than the outside diameter of the scoop so that the scoop may be inserted into the sleeve and rest on the same supporting surface as the support member.

Abstract: In a grain harvester having apparatus for measuring the moisture content of grain by directing a radio frequency signal along a measurement signal path through the grain and determining the moisture content from the phase shift and attenuation experienced by the measurement signal, calibration apparatus is provided for calibrating the moisture measurement apparatus without interrupting the grain harvesting operation. An attenuator, calibrated to a traceable standard, is selectively inserted into the measurement signal path to produce an expected attenuation of the measurement signal. The actual attenuation resulting from the insertion of the attenuator is compared with the expected attenuation and the difference is used to derive a control voltage for controlling the gain of the measurement signal path.

Abstract: A method and apparatus for guiding an agricultural implement having transversely extending arms by spraying the ground with a band of a fluorescent chemical from an end of one of the extending arms of the agricultural implement to mark the end of the area covered by a first pass of the agricultural implement, directing an optical beam having a width substantially greater than the band of fluorescent chemical onto the band of fluorescent chemical to fluoresce a portion of the band of fluorescent chemical which produces a fluoresced region on the band of fluorescent chemical, and positioning a detector on the band of fluorescent chemicals to detect the fluoresced region on the band of fluorescent chemical to determine the position of the implement with respect to the fluoresced region and thereby maintain the implement on course.

Abstract: A pair of GPS receivers A and B which are constructed in the form of the receiver antenna combinations with receivers/antenna combinations which have been associated as ground-planes that extend beyond them. They are arranged such that the lower surface of the ground-plane of one receiver is adjacent to an RF absorber sheet, and the bottom of the RF absorber sheet is placed from the top of the second GPS receiver. This structure allows for the mask angle of the GPS receiver B to be matched to the mask angle of the GPS receiver A. When the normal path signal received by GPS receiver A becomes so large that it interferes with the direct signal to an unsatisfactory degree, reception is switched to GPS receiver B which senses only multi-path signals, but which allows the lock of the receiver pair combination to be maintained.

Abstract: A broken tine detector for agricultural machines is provided for machines such as balers and forage harvesters. The tines form a first plate of a capacitor which rotates about the axis of a reel. The second plate of the capacitor may be provided by a back-plate which is located at the front of an agricultural machine adjacent to the ends of the tines and which is connected to machine ground. An alternate embodiment of the invention is devised by utilizing conductive strips on a tine guard. Each of the conductive strips may be utilized to form the second plate of the capacitor. The row of tines pass through individual slots in the tine guard so that a particular row in which the tine is broken may be detected. When a tine is broken the total capacitance between the tines and the back-plate will change and will be detected, and an indication will be supplied to an operator so that the operator may stop the machine and remove the tines.

Abstract: An on-the-go probe for determining the presence of chemical residue in a soil using Transient Infrared Spectroscopy by pulling a soil implement through the soil with the soil implement having a heating or cooling source for temporarily creating a temperature differential between a layer of soil proximate the soil implement and a layer of soil remote from the soil implement, and moving the soil sufficiently fast with respect to heating source to enable measuring the radiation characteristics of the thin layer of soil before the thin layer of soil begins to self-absorb and substantially change its emission characteristics.

Abstract: A acoustic-penetrometer probe and method for determining the presence of materials in a region proximate the penetrometer probe through measurement of reflected acoustic waves, with the probe having a driving head on one end to permit forcing the driving head into the soil, with the probe including an acoustic generator mounted in the probe for generating a below-ground acoustic wave that normally travels away from the acoustic generator, and an acoustic detector located in the probe to measure acoustic waves reflected from objects or materials located proximate the probe to thereby provide a user with information on the presence of materials proximate a radial region located around the probe.

Abstract: A sine wave oscillator provides an input signal to a step-recovery diode (SRD). The SRD produces a wideband series of harmonics of the frequency of the sine wave oscillator that are represented as "lines" in a power r.f. frequency plot. The output of the SRD is supplied to one or more bandpass filters or lowpass filters which provide selection windows so that only a specified number of harmonic lines are passed within a selection window. These specified harmonic lines are then coupled to one or more high speed input switches which are coupled to one or more high speed selection switches. The high speed selection switches are each coupled to a separate bandpass filter that is tuned to a different bandpass frequency range. Each bandpass filter corresponds to one or to several adjacent lines of the selection windows.

Abstract: A logarithmic video detector/r.f. limiter amplifier provides an amplitude-limited r.f. carrier version of an input signal. The amplitude-limited signal is either employed directly or is coupled to a mixer that produces a down-converted constant-amplitude signal which is applied to a first optical modulator which in turn is coupled to an optical source. The optical modulator is coupled to an optical fiber that carries the frequency component of the input signal at a first light wavelength. The amplifier also supplies a signal which is dependent upon its logarithmic detector response that represents the amplitude component of the input signal. This signal is supplied to a VCO which drives a second optical modulator which is coupled to a second optical source and produces an optical signal of a second light wavelength. In a first embodiment, both optical signals are supplied to the receiver over the same optical fiber link.

Abstract: A SQUID, nominally of the "hybrid" type, wherein the normally superconducting modulation coil is modified to instead be a non-superconducting material, nominally manginin, exhibits reduced long-term, or d.c., thermal response. When an alternating current waveform--rising to a nominal 130 ma. r.m.s. amplitude within a nominal 0.5 seconds and, after a nominal 100 msec. to 20 sec. duration, returning to 0 within a nominal 0.1 sec--is applied to the non-superconducting modulation coil of such a SQUID at superconducting temperature then the entire SQUID thermal response, particularly including the short-term, or a.c., SQUID thermal response, is thereafter reducible to essentially 0. The process is hypothesized to "deflux" the SQUIDs of fluxons trapped during the cool-down of superconductor within the SQUID and associated circuitry. The optimal "de-fluxing" alternating current waveform for any individual SQUID is empirically derivable.

Abstract: Disclosed is a cross-tie wall memory system for the generating, propagating and detecting of binary data represented by the presence or absence of cross-tie, Bloch-line pairs along a cross-tie wall in a thin magnetic layer. The system includes a three-level structure comprised of the following superposed layers: a straight-edged current conductive stripline; a serrated-edged thin magnetic layer data track, and a wide-narrow-edged current conductive stripline terminated on one end by a cross-tie, Bloch-line pair generator and on the other end by a cross-tie detector.

Abstract: A method of and an apparatus for magneto-resistively detecting information in a cross-tie memory system is disclosed. The detector includes a first conductive element, which is the terminating portion of an electrically-conducting wide-narrow edged propagating drive line, and second and third conductive elements that are serially aligned along a magnetic, serrated-edged data track, which three conductive elements form two gaps therebetween. The two gaps are oriented along the data track at respective narrow portions, a first narrow portion which may support a cross-tie but which second narrow portion will not support a cross-tie. A differential sense amplifier is coupled across the two gaps using the second narrow portion as a reference segment to differentially detect the presence vel non of a cross-tie in the first narrow portion.

Abstract: A method of and an apparatus for counting is disclosed. The counter includes a generator of cross-tie, Bloch-line pairs and a shift register of N stages or memory cells along which the cross-tie, Bloch-line pairs are propagated or replicated into a detector. The method includes coupling a series of bipolar push-nucleate replicate signals, each one of which produces a cross-tie, Bloch-line pair in the adjacent downstream memory cell along the shift register. When the shift register is filled, a cross-tie will appear in the detector. This provides an output signal indicating that the N memory cells have been filled by the N replicate signals.