A measurement system for converting the outputs of dissimilar transducers into digital numbers by means of a phase conversion technique. The outputs of a plurality of dissimilar transducers are generated as pairs of amplitude modulated sinusoidal signals. All AM signal pairs are converted into phase modulated signal pairs by a plurality of identical conversion circuits where the phase difference between at least one PM signal pair is linearly related to the measured parameter of the transducer associated therewith. The phase differences for each transducer is converted into a digital number by counting increments of time between the zero crossings of each pair of phase modulated signals and outputting the resulting count to a data buss of a control processor. Transducer parameters which are nonlinearly related to their phase differences are compensated by a correction factor which is calculated by knowing the error between any particular measured input and the linear input.
Vehicle Guidance System Using Angular Rate Of Change
In a vehicle guidance system, a method for computing the true rate of change of the angle between the line of sight to the target and the gyro reference. Two antennas are spaced apart a distance upon the vehicle. The outputs of both antennas are converted to a subcarrier frequency. One of the antenna outputs is then converted to a linear voltage by means of a phase detector and, subsequently, combined with the gyro reference voltage. By means of a high gain control loop and a voltage control oscillator, a combined sinusoid signal is given with both the carrier frequency and the gyro reference. In the high gain control loop, appropriate scaling factors and frequency division and multiplication must be used to eliminate repeating values of phase in excess of 360. degree. Now, by modulating the combined signal with the signal received from the other antenna, the carrier frequency can be eliminated. By further differentiation and multiplication, and the combining of the results thereof, a true rate of change of the angle between the gyro reference and the line of sight to the target can be obtained.
Dr. McPhee graduated from the New York University School of Medicine in 1969. He works in Willimantic, CT and specializes in Internal Medicine. Dr. McPhee is affiliated with Windham Hospital.