Abstract: A package of fiberglass is unwound such that the revolution of the unwinding is controlled relative to linear payout speed of the package. A strand of fiber is pulled from the package while simultaneously rotating the package about a longitudinal axis of the package.

Abstract: The present invention provides an RF spectrum measurement analyzer and method and more particularly to a GSM output RF spectrum measurement analyzer and corresponding method. One preferred embodiment of the present invention is applicable to GSM applications. However, other embodiments could be applicable to the general class of Time Division Multiple Access (TDMA) signals of which GSM, PDC (Pacific Digital Cellular), NADC and the like are a part. According to one preferred embodiment of the present invention, the method includes the steps of acquiring an RF carrier signal; converting the acquired RF carrier signal to an IF signal; converting the IF signal to a digital signal of relatively wide bandwidth; FFT filtering the digital signal to measure multiple offset frequencies within the IF bandwidth; and mathematically applying a resolution bandwidth filter at each offset.

Abstract: A package of fiberglass is unwound such that the revolution of the unwinding is controlled relative to linear payout speed of the package. A strand of fiber is pulled from the package while simultaneously rotating the package about a longitudinal axis of the package.

Abstract: A bushing balance controller controls the overall average temperature of a multiple segment glass fiber forming bushing and the temperature of each individual bushing segment. Current shunting loops divert current away from each bushing segment as required to provide the proper bushing segment temperature profile as well as the desired average bushing temperature.

Abstract: A ramp circuit for a control loop which receives a signal from a controller and sends a signal to a controllable means to limit the slew rate of the controller signal. A capacitor functions as a storage means and a reset means is provided to rapidly discharge the capacitor in the event of a decrease in power to the control loop. The capacitor is charged through a diode which limits discharge in normal operation. The discharge and reset is performed by a normally reverse biased diode and series resistance connected to the controller positive supply voltage. A current limiting means is provided to charge the capacitor a lower linear rate by turning on a transistor and shunting excess current around the capacitor. An external reset is provided by an additional diode and series resistance for connection to a remote positive supply voltage or relay contact.

Abstract: An improved bushing controller is shown which utilizes an auxiliary transformer in each of the variable impedance circuits in the controller and the bushing tha the controller is connected to increase the current capability of the controller by a significant percentage. Improved performance of fiber glass bushings producing multiple forming packages is realized.

Abstract: An improved fiber glass bushing control system. One aspect of the system has a weighing means for weighing complete collections of glass fiber strands produced from forming from a bushing through attenuation, a monitoring means for the time of attenuation at constant strand speed and a program computer means that receives signals from the weighing means and the monitoring means. The program computer means has a means for establishing a database of the weights and times, a means for determining the throughput of the glass from the bushing from the weights and times, a means for determining average throughputs and including these averages in the database, a means for comparing the average throughputs to a standard set throughput, and a means for initiating an adjustment to the main bushing temperature controller, when the average throughput deviates from the set point throughput by a value greater than the sensitivity factor of the bushing.

Abstract: A fiber glass bushing having a thermocouple embedded in the bottom thereof and a method of preparing the same is described. The thermocouple is carried in a plate member which is welded to the bushing bottom by a weld on the outside of the busing.

Abstract: A bushing controller circuit for regulating the current flow through a fiber glass bushing to thereby control the temperature of the molten glass being drawn into fibers is disclosed. The bushing temperature is measured by a plurality of thermocouples which produce an average temperature reading that is used to control the power fed to the bushing. The bushing controller circuit is a three-terminal device connected across two sections of the bushing to regulate relative current flow in the two sections, in order to control the amount of fiber produced by each section. The bushing controller circuit includes a pair of timing circuits which operate in response to the polarity and magnitude of a control signal, produced at a remote control panel, to control the conductivity of a corresponding pair of current control devices connected across respective sections of the bushing. A reset circuit produces a signal corresponding to the zero crossing of the input AC power to synchronize the timing circuits.

Abstract: A railroad highway crossing warning system including pickup coils for sensing current flowing in the track rails of an approach zone, a circuit for sensing the voltage across the track rails, band-pass filter circuits for filtering the voltage and current derived from the track rails, impedance calculator circuits for calculating the track impedance, phase detector circuits for detecting the phase angle between the voltage and current, a multiplier circuit for linearizing the track impedance by multiplying the track impedance by a function of the phase angle, a data sampler circuit for sampling the linearized track impedance at given periodic intervals, a motion detector and crossing predictor circuit for detecting the motion of a train and for predicting the time of arrival at the crossing by comparing the predicted time of arrival with an advanced warning time, and a logic gate circuit for activating the warning apparatus at the crossing when the predicted time of arrival is less than the advanced warning t

Abstract: A fail-safe AND logic circuit including a free-running multivibrator and a pair of voltage reference networks. The multivibrator includes a pair of common emitter transistor amplifiers. The transistor amplifiers are separately biased and powered by an individual one of a pair of voltage reference networks so that a.c. oscillations are produced by the multivibrator when a separate negative-going pulse coincidentally appears on both of the pairs of voltage reference networks.

Abstract: A high power amplitude modulated audio frequency transmitter having a Twin-T low frequency oscillator, a tickler coil high frequency oscillator, a switching regulator and a switching amplifier. The Twin-T low frequency oscillator produces a sine wave modulating signal which is fed to the switching regulator. The tickler coil high frequency oscillator produces a carrier signal which is fed to the input end of the switching amplifier. The output signal of the switching regulator is fed to the output end of the switching amplifier so that a sine wave modulated signal is developed on the output of the switching amplifier.

Abstract: A train detection system for protecting a railroad highway crossing having an a.c. transmitter center-feeding voltage signals into the track rails and having a receiver including at least a pair of coils located on opposite sides of the crossing and disposed adjacent the track rails for defining an island zone and for inductively picking up a.c. signals when the island zone is unoccupied and determines the time of arrival of a train at the crossing.

Abstract: A highway crossing warning system for monitoring the motion and predicting the time of arrival of an approaching train at the highway crossing and for detecting the presence of a broken rail in the approach zone by feeding dual frequency signals into the track rails and measuring the track impedances at the two frequencies and the phase angle of the lower of the two frequencies.

Abstract: A solid-state overload protection circuit for protecting a multiple-stage compound transistor power amplifier. The overload protection circuit includes a current-limiting circuit for sensing or limiting the current during an overload condition. The current-limiting circuit includes a transistor which conducts to limit the current in the output stages of the multiple-stage power amplifier. A monitoring circuit including a timing circuit, a comparator, and a switching transistor monitors the duration of the overload condition and disables the input stages of the multiple-stage power amplifier when a prolonged overload condition persists.

Abstract: A low frequency modulating signal and a high frequency carrier signal circuit employing a twin-T oscillator having an integrated circuit operational amplifier for producing the modulating signal and an L-C resonant feedback oscillator having a transistor amplifier for producing the carrier signal, and a monitoring shunt regulator for supplying a reference potential to the twin-T oscillator and biasing and operating potentials to the L-C resonant feedback oscillator and for deactivating the L-C resonant feedback oscillator when an increase in resistance occurs in the shunt regulator.

Abstract: A solid-state inverter having a programmed unijunction transistor oscillator for converting a d.c. supply voltage into a.c. oscillations which trigger a bistable transistor multivibrator for producing square-wave signals which are applied to a compound-connected transistor amplifier for energizing a load and having an overload protection circuit which disables the compound-connected transistor amplifier and which, in turn, deenergizes the load during the presence of an overload condition.