ROBERT GORDON SHAFFER
Pilots at Barrie Cir, Gardenville, PA

4251869, Feb 17, 1981

May 14, 1979

6/038422

Robert G. Shaffer - New Britain PA

Fischer & Porter Company - Warminster PA

G01R 2302, G06F 1520

364484

A converter capable of accurately and rapidly converting an input signal whose frequency varies as a function of a parameter being metered into a bit parallel number for manipulation by a digital computer. The incoming signal, before being applied to the converter, is shaped to produce a continuous train of square wave periods, each beginning with a leading edge. A measurement is made during a time interval which need not be synchronized with the input signal and is independent of its frequency, the interval having a fixed duration which is a predetermined multiple of a given unit of time. In this interval, the following factors are measured in the slice of the square wave train falling between the start and finish points of the interval: the number of time units occurring between the start point and the leading edge of the first complete wave period in the slice; the number of complete wave periods lying within the slice, and the number of time units occurring between the last leading edge appearing in the slice and the finish point. The measured factors are applied to the digital computer which determines the frequency of the incoming signal in binary terms from the equation relating frequency to these factors.

4123940, Nov 7, 1978

Sep 23, 1977

5/836150

Peter J. Herzl - Morrisville PA
Robert G. Shaffer - New Britain PA

Fischer & Porter Company - Warminster PA

G01F 132

73194VS

A transmission system for a vortex-shedding flowmeter adapted to measure the flow rate of fluid passing through a flow tube by generating fluidic oscillations whose frequency varies with flow rate. These oscillations are detected by a sensor/resonator included in the frequency-determining circuit of a carrier oscillator having a predetermined center frequency. The carrier frequency is caused to deviate from the center frequency at a rate depending on the frequency of the fluidic oscillations and to an extent depending on the amplitude of these oscillations to produce an F-M carrier signal which is mixed with a local oscillator signal to produce a negative beat signal having a relatively low frequency. Though the deviation in the carrier frequency produced as a function of fluid flow rate represents a small percentage change, this same deviation as reflected in the beat signal represents a greatly multiplied percentage change and hence gives rise to a significant increase in sensitivity. The beat frequency is applied to an F-M demodulator to yield an output voltage whose frequency is a function of flow rate, this voltage being converted into a varying D-C flow signal that is transmitted over a two-wire line.

4084155, Apr 11, 1978

Oct 5, 1976

5/729778

Peter J. Herzl - Morrisville PA
Robert G. Shaffer - New Britain PA

Fischer & Porter Co. - Warminster PA

G01F 132, G01R 2306, G08C 1902

340210

A two-wire transmitter operating in conjunction with a meter whose output signal varies in frequency as a function of the metered variable. The meter signal is changed into an analog voltage that is converted by the transmitter into a corresponding output current and conveyed to a receiving station over a two-wire line which also supplies operating voltage to the transmitter. In the transmitter, the analog voltage is applied to a differential amplifier which converts the voltage into an output current via a transistor acting as a variable impedance across the line to make up the difference between the operating current drawn by the transmitter and the output current. This make-up current is stored to provide an energy source for operating a totalizing counter coupled to the meter to determine the total amount of the variable passing through the meter.