Abstract: An address and data bus connects a multiplicity of ports into which test modules can be inserted with a microcomputer controlled by a keyboard for performing tests on circuit boards or other electronic units through test plugs that are interconnected with the data ports where the test modules are plugged in. When the test system is put into operation, all of the ports of the data bus are addressed to produce an indication of which ports are occupied by test modules as well as of the nature of the test modules. When it is desired to produce a test, each step of the procedure is performed by operation of a keyboard with reference to available options presented on the computer display on the basis of the configuration of test modules that have been plugged in. Coupling fields are interposed between data ports designed to receive test modules utilizing analog circuits and a test connector for connection to equipment under test.

Abstract: In order to generate a signal having a well-defined feature which exactly coincides with the zero-crossing point of an input signal, for example in order to define the top dead center position of the crankshaft of an engine for the purpose of valve and ignition timing, the invention provides a circuit which is prepared by the passage of the first half of an input signal across a predetermined threshold. When the first threshold is exceeded, the circuit opens a switch which connects a source of reference potential, equal to the zero crossing point of the input signal, to the threshold switch, to represent a second threshold. As the input signal crosses that second threshold level, which constitutes the zero crossing point, the threshold switch closes, thereby generating the trailing edge of the output signal which constitutes a signal feature coincident with the zero crossing point and hence with a fixed angular position of the rotating shaft.

Abstract: To match the control adjustment speed of an internal combustion engine control system to operating speed thereof, a control loop is provided which includes an operating parameter sensor, a correlator comparing a sensed signal with an oscillating command signal, a controller responsive to a consequent error signal and which then controls operation of the engine; a speed transducer provides speed-dependent output signals which control (a) the frequency of oscillation of the oscillator and (b) the operating speed of the controller. If the controller is an integrating-type controller, then the time constant of the integrator thereof is changed, for example by varying a resistance value of an R/C circuit as a function of engine speed.

Abstract: The ignition coil of the system has its primary serially connected with a transistor which controls current flow therethrough. Ignition pulses are provided by an ignition pulse source, for example an inductive transducer. The recurrence rate of the ignition pulses is analyzed and a corresponding control signal is obtained which controls the timing interval of a timing circuit, the timing circuit determining the ON, or connected time, of the transistor or similar controlled switch in series with the primary of the ignition coil. Analysis of the recurrence rate is, simply, done in a pair of integrators, alternately effective and storing the time interval between alternate, succeeding ignition pulses, which permits control of current flow through the ignition coil for a period of time just sufficient for current flow to reach saturation without, however, causing current flow while the circuit is saturated, thus preventing unnecessary heating of the ignition coil and associated components.

Abstract: Sequentially generated charge pulses are applied to the spark gap through a diode which prevents back-flow of energy applied to the spark gap, the capacity of the ignition cable, or a capacitor, and of the spark gap causing a build-up of charge accumulation as a result of the sequentially applied charges, until the gap breaks down; the breakdown voltage, therefore, will be determined by the conditions of the gap. The pulses are generated at a pulse repetition rate which is high with respect to the rate of generation of spark impulses through a circuit in which the respective capacities and winding ratios and inductances of the ignition coil and the cabling are controlled so that the pauses between sequentially generated spark pulses and the timing of the spark pulses can be matched to the system parameters.

Abstract: A switch connected in series with the ignition coil is "on" and "off," respectively, in the presence and absence of a pulse furnished by a pulse generator operating in synchronism with the crankshaft of the engine. If the pulse width of the pulses is too small for the current in the ignition coil to reach the minimum value required for ignition, the closing time of the series switch is advanced, while if the pulse width is too long, causing excess heat dissipation in the coil, the closing time of the switch is retarded. To accomplish this, a first digital counter counts downwards for a predetermined time and upwards for a time period in which the current in the ignition coil exceeds a predetermined current. Upon interruption of the current in the coil, the then-present value in the first digital counter is transferred to a second digital counter. The second counter then counts down at a predetermined rate until a predetermined count is reached.

Abstract: A universally applicable system should permit easy matching of ignition timing characteristics to specific engines. In order to control a digital electronic ignition system, a marker signal is generated when a piston has reached a predetermined angular position with respect to upper dead center (UDC) position, and additional marker signals are generated as the piston moves, for example by sensing the teeth on a starwheel coupled to the engine or, for example, in an automotive engine by providing signals each time a tooth of the starter gear passes by a transducer. Two counter stages are provided which go through two count cycles for any one ignition event. The marker starts counting of both counters. The first counter stage counts for a predetermined time interval to provide a speed-dependent output number which is stored in a multiplex or memory stage, the output of which is blocked while the second counter counts.

Abstract: The ignition coil has a tapped primary winding which forms a first partial primary portion and a second primary portion, the second primary portion having an inductance which is high with respect to the partial primary portion. A supply circuit, including a controlled switch, is connected in circuit with the first partial portion to energize the partial portion when the controlled switch is closed, so that the partial portion is energized in successive pulses separated by time intervals. A shunt circuit is connected to the second primary portion and carries the induced current during gaps in energization pulses applied to the primary partial portion and arising at the end of the pulses, both the shunt and the main energization circuits being interrupted at the ignition instant to thereby produce a high-voltage pulse in the secondary. The pulsed current supplied to the primary saves current and loading of the ignition coil.

Abstract: To provide for precise shifting of gears in automatic transmissions in dependence on vehicle speed and loading on the engine, a speed signal and a throttle position signal are applied to separate control stages one to control up-shifting and the other to control down-shifting; further, a separate kick-down switch is provided for rapid down-shifting. The control stages are so arranged that up-shifting is commanded in accordance with vehicle operating characteristics, but down-shifting is commanded only with a lag, or hysteresis, with respect to the vehicle speed, to prevent excessive shifting of the transmission. The shift control circuits may be either separate trigger circuits controlling up-shifting and down-shifting of the respective gear ranges, or may be separate networks processing the respective input signals (speed, engine loading) and providing output control signals to a shift control trigger circuit.