Abstract: A method and apparatus for increasing the resolution and accuracy of flow measurements made by vortex flowmeters. A signal conditioning circuit connected to a vortex sensor generates a vortex signal having a period that varies with the frequency of the vortex street. The period of this vortex signal is measured by a period sampling circuit, which generates a vortex period signal. When a programmable control circuit determines that the change in the frequency indicated by successive values of the vortex period signal is relatively small, the displayed flow value is based on the current frequency of the vortex signal; when the change in frequency indicated by successive values of the vortex period signal is relatively large, the displayed flow value is based on the running average frequency of the vortex signal.

Abstract: A transducer for sensing the angular position of a shaft over a limited angle (e.g., .+-.30.degree.) uses a printed circuit board mounted perpendicular to the shaft between capacitor plates of a bifurcated vane clamped to the shaft. The board has two pairs of symmetrical capacitor plates, one pair on each side with each plate of a pair located symmetrically with respect to the midposition of the vane plates, and corresponding plates of each pair connected together at a junction to place the two corresponding variable capacitors in parallel. Circuitry produces a Mark-Space signal proportional to the position of the bifurcated vane. Using the total Mark-Space period to continually derive a midposition reference, and comparing that midposition reference to any deviation of equal Mark and Space periods provides a position signal proportional to deviation from midposition of the bifurcated vane.

Abstract: A totalizer of the decade counter type or the like which, when being pulsed, tends to drain a battery, where the battery and totalizer are remotely located. The battery thus needs to have a long life because of its remote location. The same is effected by a circuit including a voltage regulator which holds average power constant, at least from pulse to pulse.

Abstract: An ultrasonic flowmeter including two phase locked loops with four voltage controlled oscillators, a portion of each loop forming a common path through amplifiers, an electronic attenuator with automatic gain control, a pulse detector, and a pulse or phase comparator. The pulse comparator, through switches, controls the voltage controlled oscillators on a time shared basis. The voltage controlled oscillators are always driven until a later counter pulse coincides with a corresponding received pulse. Time sharing is, in part, accomplished by beginning energy propagation in opposite directions at successive times and before either pulse is received. The oscillators are also alternated to eliminate a zero frequency shift by transmitting alternately at higher and lower frequencies from each transducer.

Abstract: A flowmeter sometimes called ultrasonic, but sometimes not ultrasonic including two phase locked loops, a portion of each of which form a common path through amplifiers, an electronic attenuator with automatic gain control, a pulse detector, and a pulse or phase comparator. The pulse comparator, through switches, controls first and second voltage controlled oscillators on a time shared basis. First and second counters are connected from the first and second voltage controlled oscillators, respectively. The first and second counters supply transmission pulses to submerged first and second facing transducers, respectively, at different times. The voltage controlled oscillators are always driven until a later counter pulse coincides with a corresponding received pulse. Time sharing is, in part, accomplished by beginning energy propagation in opposite directions at successive times and before either pulse is received.