Abstract:
A method for simultaneously imposing a single modulating signal on a number of constant frequency carriers includes applying the single modulating signal and all of the carriers to a doubly-balanced mixer circuit that produces sideband signals that are uncontaminated by the carriers. The sideband signals thus produced are then combined with signals proportional to the carriers in a linear circuit to obtain an output signal equivalent to a signal that would result from combining separately modulated carriers.
Abstract:
Circuitry for simultaneously generating a set of carriers having preselected frequencies in the amplitude modulation broadcast band includes a circuit for producing a train of pulses having a crystal-controlled pulse repetition frequency equal to the separation in frequency between successive assignable frequencies in the broadcast band, each pulse in the train having a pulsewidth approximately equal to the reciprocal of the frequency of the lower end of the broadcast band and having a rise time approximately equal to the reciprocal of the frequency of the upper end of the broadcast band, so that the spectrum of the train of pulses includes components having frequencies equal to all of the assignable frequencies in the broadcast band, the pulse train being applied to a set of phase-locked oscillators connected in parallel, each oscillator being tuned to a different one of the selected components of the train of pulses.
Abstract:
A system for assessing the effectiveness of a water softener or comparable liquid-processing apparatus whose effectiveness is related to the difference between the electrical conductivity of the liquid supplied to the apparatus and the electrical conductivity of the liquid that has passed through the apparatus includes two inductance loop conductivity sensors excited by a common signal generator. The outputs of the sensors, which typically include unwanted quadrature components, are applied directly to the inputs of a differential amplifier. The resulting difference signal is then applied to a detector that is gated by the common excitation signal, so as to produce a detected signal that is substantially unaffected by the unwanted quadrature components. In a preferred embodiment, each of the inductance loop conductivity sensors includes two electrodes connected by a conductor that links two toroids.
Abstract:
Apparatus and a method for generating all of the assignable carrier frequencies in the FM broadcast band and for frequency modulating the generated carriers includes a generator of a train of pulses having a crystal-controlled repetition frequency and a specific pulse shape which together produce a spectrum of odd harmonics of the pulse repetition frequency whose separation in frequency is identical to that of the assignable carrier frequencies. This pulse train is then mixed with a 98.0 MHz sine wave to translate the spectrum to the FM band. Simultaneous modulation of all the carriers is achieved by frequency modulating the 98.0 MHz sine wave, whereby the same modulation is imparted simultaneously to all of the carriers.
Abstract:
A method for detecting the depth of a liquid body. A source of pressurized gas is engaged to a weighted sensor by means of a single elongated tube. The sensor is positioned at the bottom of the liquid body. A solenoid valve, which regulates the flow of gas in the tube, is periodically opened to provide a pulse of overpressure which exits the underside of the sensor in a pressure-equalizing stream of bubbles. After a brief, predetermined settling time, a reliable pressure/depth indication is obtained from a transducer in communication with the single tube.
Abstract:
A calibrator especially suitable for calibrating electromagnetic flow velocity sensors under field conditions requires no source of water and no source of electrical power. The calibrator includes a pickup coil that intercepts all or a known fraction of the flux generated by the sensor and generates a voltage in response to the flux. The voltage is applied to the electrodes of the sensor thereby simulating a flow velocity. The gain of the sensor is adjusted so that the simulated flow velocity equals a pre-determined reading. The pickup coil may include a number of taps that may selectively be connected to an electrode of the sensor to simulate flow velocities of various magnitudes, thereby permitting the linearity of the sensor to be checked. The calibrator also includes a direct conductive path that may selectively be connected between the electrodes of the sensor to simulate the zero flow velocity condition, thereby permitting the zero offset of the sensor to be checked.
Abstract:
A flow meter for detecting and recording a plurality of data points representative of the depth and velocity of liquid flow in an open container. A weighted sensor has a dimpled surface to induce turbulence at low velocities to assure a substantially linear velocity characteristic. An electromagnetic velocity transducer and a single tube bubbler are engaged to the sensor to provide data which is periodically read into a cassette recorder. A microcomputer controls timing functions with respect to the collection and recordation of data within the system.
Abstract:
This invention provides a process for preparing a dehydrated banana which comprises slicing the fruit of a ripe banana along its length from 1 to 3 times to form lengthwise peeled banana slices having the carpel region exposed along their length, contacting the slices with steam to increase the temperature of the interior of the slices up to about 85.degree.C to 95.degree.C and maintaining that temperature for about 1/2 to 4 minutes, and dehydrating said steam blanched slices at a temperature from 50.degree.C to 65.degree.C to reduce the moisture content of the banana slices to less than about 20%. The slices are contacted with steam before they are substantially discolored due to enzymic discoloration. The product obtained thereby retains a substantial portion of the characteristic cellular structure of the banana, is substantially free of enzymic discoloration, has a water activity of less than about 0.6, and is rehydratable to yield a product with an appearance, texture, color, aroma and flavor similar to that of fresh ripe banana pulp. The dehydrated product retains those properties for at least 3 months under normal storage conditions.
Abstract:
Apparatus for simultaneously receiving a plurality of AM signals of widely differing strengths on a set of carrier frequencies and for re-broadcasting the AM signals at equalized strengths at either the original carrier frequencies or at a set of carrier frequencies that are offset from the original from the received frequencies by a constant difference. Regardless of whether the re-broadcast carriers are offset, the system includes provision for interrupting the re-broadcast signals by an audio message of general interest or public safety.
Abstract:
A system and a method for controlling the concentration of dissolved matter in a liquid in a boiler or still, wherein a first sensor measures the electrical conductivity of the incoming liquid and a second sensor measures the electrical conductivity of the liquid in the boiler or still. The measured conductivities are then compared and a signal is generated which represents the relation of the conductivities. This signal is, in turn, compared with a preset value and the difference is used to control the flow of incoming liquid which serves to dilute the liquid in the boiler.