摘要:
This invention relates to a fail-safe duty cycle checking circuit comprising an amplifier circuit having a first input for receiving a square wave of fixed peak to peak amplitude and a second input for receiving a signal proportional to the duty cycle of the square wave, and an output, a feedback loop connected between the output and first input for providing an upper and a lower hysteresis level which levels shift upward or downward in accordance with the duty cycle of the square wave, the shifting of the hysteresis levels too far upward or too far downward rendering the amplifying circuit incapable of producing an output, and a photosensitive device having a radiant energy source connected in the feedback loop for monitoring its condition. The photosensitive device also has a photopositive resistive element connected to the first and second inputs of the amplifier circuit to assume a high impedance condition whenever the radiant energy source emits no radiant energy thereby rendering any square wave input incapable of producing an output from the amplifying circuit.
摘要:
This invention relates to a vital type of vehicle overspeed circuit arrangement for receiving variable frequency signals from a speed sensing device. The variable frequency signals are applied to a single break passive low-pass filter which attenuates the signals at a rate of 6db per octave. The attenuated signals are fed to an input amplifier which couples the amplified filtered signals to a selection network. The selection network includes a plurality of active switching stages a select one of which is activated for controlling the gain of a variable gain amplifier. The variable gain amplifier is coupled to an output amplifier which produces an output voltage having a value which is proportional to the frequency of the signals and the gain of the variable gain amplifier.
摘要:
This invention relates to a fail-safe variable type of low-pass filtering circuit. The filtering circuit includes a passive R-C network and an active semiconductive amplifying stage. The upper transmission frequency of a.c. input signals is varied by changing the resistance of the R-C network.
摘要:
This invention relates to a vital type of selectable active lowpass filtering circuit. The selectable low-pass filtering circuit includes a half section resistance-capacitance filter network and a variable gain transistor amplifier. The input of the transistor amplifier is coupled to the half section resistance-capacitance filter network and the output of the transistor amplifier is selectively coupled to one of a plurality of load resistors each of which establishes a different gain for the transistor amplifier.
摘要:
An asymetrical, astable multivibrator, at the control location for a multiple unit train, transmits a control signal having a selected duty cycle characteristic over a single train line channel. The duty cycle percentage is selectively varied by a transistorized switching bank which connects different resistors into the RC timing circuit for one-half of the multivibrator element, the other half having a fixed timing circuit. These switching transistors are selectively controlled by the train operator in accordance with the desired train operating mode. The transmitted control signal is received on each car and converted into an average voltage whose level varies with percent duty cycle. On each car, this average voltage is compared, in a transistorized comparator element, with a reference voltage preset in accordance with the desired operating mode of that car within the overall train operation. When the average voltage is less than the reference voltage, a controller on that car is actuated to control the car function. With different reference voltages preset on the several cars, sequential activation of the car control functions may be obtained.
摘要:
This disclosure relates to a rate parameter indicator which uniquely allows extremely accurate measuring and indicating of a rate parameter at low rates due to provision of a smooth linear signal to an indication meter circuit. The system incorporates a low-voltage drift switching circuit which is coupled to a constant reference voltage source and receptive to constant-width pulses, the frequency of which is proportional to a rate parameter. A meter jitter minimizing circuit is electrically coupled to the low-voltage drift switching circuitry, as well as the constant voltage source, and includes an averaging circuit which allows the meter jitter minimizing means to provide the aforementioned smooth linear signal to the indication meter circuit in a unique manner.
摘要:
This disclosure relates to a high rate parameter measuring system which uniquely allows extremely accurate rate measuring due to removal of indication nonlinearity as well as the removal of inaccuracies due to reading over wide ranges of ambient temperatures which are intrinsic to the environment of said system. The system incorporates pulse-squaring circuitry which square incoming rate pulses indicative of said rate parameter, associatively coupled to monostable circuitry including an operational amplifier which monostable circuitry provides a constant pulse-width output, said pulse-width output, said monostable circuitry output electrically coupled to a metering circuit which produces a linear indication of the rate of said incoming rate pulses and includes a solid state semiconductive component which uniquely cooperates with the aforementioned components to provide the desired results.
摘要:
THIS INVENTION RELATES TO A PULSE GENERATOR FOR PRODUCING ELECTRICAL PULSES WHERE A ROTOR, POSSESSING FLUX DISTRIBUTION QUALITIES SUCH THAT THERE EXISTS AT LEAST ONE REGION OF HIGH FLUX DENSITY SOURROUNDED BY REGIONS OF LOW FLUX DENSITY WHEN IN THE PRESENCE OF A MAGNETIC FIELD, IS ROTATED IN THE VICINITY OF AN INDUCTOR MEANS. THE ROTOR INCLUDES AT LEAST ONE MAGNETIC MEANS WHICH DEFINES ONE OF THE REGIONS OF HIGH FLUX DENSITY. THE INDUCTOR MEANS HAS INPUT AN OUTPUT TERMINALS. A SIGNAL IS IMPRESSED ON THE INPUT TERMINALS. UPON ROTOR ROTATION, ELECTRICAL PULSES APPEAR AT THE OUTPUT TERMINALS OF THE INDUCTOR MEANS. AN OUTPUT SIGNAL FOR ANY ROTATIONAL SPEED IS ATTAINED WHEN THE INDUCTOR MEANS IS A SATURABLE INDUCTOR. THE PULSE GENERATOR IS EXTREMELY COMPACT, SIMPLE IN MECHANICAL LAYOUT, AND HAS HIGH RESOLUTION PROPERTIES.
摘要:
A vital electronic circuit arrangement which includes a low-pass filter network for passing a.c. signals. A transistor amplifier for amplifying the a.c. signals and for supplying the amplified a.c. signals to a step-up transformer. The transformer includes a controllable tap primary winding for discretely varying the turns-ratio of the transformer in accordance with the frequency of the a.c. signals.
摘要:
A special signal is transmitted through train line communication channels from a transmitter means on one car to a receiver means on the other car of the self-propelled train unit. The transmission of this signal is controlled by the propulsion control logic means located on one car. The receiver means includes a relay which controls the propulsion condition of one of the cars, normally the trailing car, shifting between direct, multiple unit control from the operator''s position and a preset condition, e.g., propulsion off, as the special signal is or is not received. The special signal may be direct current energy or alternating current energy having a selected frequency characteristic. This latter signal is superimposed on train line channels used for other purposes, e.g., the directional train line wires. The direct current signal, however, requires a separate, dedicated train line channel used in conjunction with the directional train line wires.