Abstract: A method for compensating a rod position indication system for non-linearity comprises the steps of applying an excitation current to a primary of a sensor for inducing a generally linear voltage that is representative of the position of a control rod on a secondary of the sensor. The excitation current includes a first frequency which is sufficient to provide the generally linear output for the sensor. The excitation current is then modified to include a second frequency which is sufficient for providing the generally linear output when the first frequency is insufficient to provide the generally linear output.

Abstract: A method for magnetic coupling compensating a rod position indication system having at least two rod position indicators each having induced noise comprising the steps of applying a sinusoidal current to a primary of the first rod position indicator for inducing a voltage on a first secondary of the first rod position indicator; receiving both the first secondary voltage from the first rod position indicator and a second secondary voltage, induced from the noise, of the second rod position indicator; and deriving a difference of the first and second secondary voltage for obtaining the magnetic coupling compensation.

Abstract: There is disclosed a transit vehicle speed control apparatus and method operative to control the speed of the vehicle in relation to the lowest one of an input command speed limit and a program stop speed limit by determining the time period required for the vehicle speed to change from a present speed to a predetermined speed band limit in relation to each of the acceleration of the vehicle and the response delay time of the vehicle in accordance with the propulsion motor characteristics and the vehicle mass.

Abstract: A more failsafe signal voltage threshold determining apparatus is disclosed for operation in a train vehicle control system, and which utilizes the forward voltage drop characteristic of an input light emitting diode of an optical isolator device as a train vehicle control signal threshold reference. The detector transistor of the optical isolator device provides an output control signal in response to an input train vehicle control signal applied to the light emitting diode which has a voltage level high enough to overcome the light emitting diode voltage drop.

Abstract: The present invention relates to an improved dynamic brake effort control apparatus for use with loads such as a transit vehicle, and which provides a better control of and blending of dynamic brake effort and friction brake effort in relation to the vehicle speed for the improved braking control of the transit vehicle.

Abstract: There is disclosed a passenger vehicle speed maintaining control apparatus and method, including program microprocessor control apparatus for controlling the vehicle speed in response to an acceleration or tractive effort request P signal.

Abstract: An improved failsafe logic function apparatus is disclosed which includes an input signal section and an output signal section, with a middle gating network section isolated from each of the input signal section and the output signal section. An external control signal determines the logic function operation of the apparatus.

Abstract: A signal amplifier and clipper apparatus is disclosed including two four terminal capacitors and an operational amplifier to obtain fail-safe voltage gain which will not increase due to the failure of any element of the apparatus. A signal clipping operation is provided by the saturation of the operational amplifier output at the supply voltages, such that a maximum output signal level is provided by a fail-safe attenuator operation that will not decrease.

Abstract: A signal bandpass filter apparatus is disclosed wherein a direct short circuit between input and output is prevented and the loss of the ground reference of the filter is detectable and fail-safe in operation.

Abstract: A signal decoder is disclosed for use in a transportation vehicle control system in which vehicle control signal information bits are transmitted according to a multiple message frequency, FM, PSK, or FSK, comma-free binary coded command signal. The disclosed invention uses selective receiver channels for each command signal message frequency to detect information bits according to the selected message frequency. The detected information bits of each receiver channel are separately stored to comprise a separate information history for each message frequency and these information bit histories are then individually decoded. The decoded signals are compared to detect a discrepancy between any of the decoded signals due to component failures, signalling system noise, or component transient conditions. For any discrepancy between the decoded signals, a fail-safe comparator reduces the decoded signal to a more safe condition.

Abstract: In a typical transportation vehicle control system, coded control information is transmitted to the transportation vehicles on vehicle command signals comprised of multiple message frequencies. A decoder is disclosed for decoding, in a fail-safe manner, information from message words which are comprised of message units carried on the multiple message frequencies. Vehicle speed command signals which are received by an antenna are amplified and frequencies which are substantially the same as the message frequencies are filtered from these signals. The filtered message frequencies are again amplified before message units are separately detected from each message frequency by a related filter-discriminator. The message units detected from a first message frequency by the related filter discriminator are delayed for the number of message units which comprise a message word. The message units detected from a second message frequency by the related filter-discriminator are inverted.

Abstract: A receiver is disclosed which is used in a transportation vehicle detection system to compare logic conditions in signals which are transmitted from a first vehicle pathway location, with logic conditions which are detected from signals received at a second vehicle pathway location. When first and second enable signals correspond, the signal from an oscillator is transmitted through two pairs of fail-safe AND gates and applied, through a fail-safe OR gate, to a latch circuit which signals the transportation system speed controller that no vehicle is present between the first and second pathway locations. When the first and second enable signals do not correspond, the signal from the oscillator is not transmitted through both pairs of fail-safe AND gates, there is no signal applied to the fail-safe OR gate, and no signal is applied to the latch circuit which signals the transportation system speed controller that a vehicle is present between the first and second pathway locations.

Abstract: There is disclosed an input signal threshold responsive apparatus for responding to a predetermined input signal energy level, in relation to a voltage and time product, before an associated train vehicle control system is enabled by a provided gated enable signal. The provided apparatus responds to one of a plurality of input signals, having respectively different frequencies and different amplitudes, and provides an enabling output signal.It is desired to provide an improved threshold sensitive input signal receiver apparatus in conjunction with train vehicle control and in relation to plural stray signals in a given track circuit signal block due to cross talk from adjacent signal blocks and the like. The input signal responsive or sensitivity threshold is established in relation to the practical required signal level of the desired signal to be received within the given signal block.

Abstract: A signal bandpass filter apparatus is disclosed wherein a direct short circuit between input and output is prevented and the loss of the ground reference of the filter is detectable and fail-safe in operation.