Abstract: A system (10) and method manages battery (13) power in a wheel module (11) for indicating when air pressure in a tire falls below a recommended value. Tire air pressure is sensed with a pressure sensor (16). Tire air temperature is sensed with a temperature sensor (18). A determination is made whether the air pressure is increasing or decreasing with respect to time. Based upon whether a ratio of the air pressure and the air temperature is increasing, decreasing or remaining constant with respect to time, tire motion is inferred without directly sensing acceleration or movement of the tire. Power management circuitry (14) controls battery power to enable sensing of air pressure and air temperature at measurement intervals that are longer in time when the tire is not in motion.

Abstract: A digital speed control system includes a first binary up-counter called an Actual Count Register. The Actual Count Register is initially reset to contain all "0"'s. During a sample time, an input is applied to the Actual Count Register so that it counts up to a first binary number during the sample time. The first binary number represents a reference speed. The system includes a Reference Count Register. In response to read and store command, the first binary number is loaded into the Reference Count Register, where it remains until the next request for a new reference speed. The system further includes a first binary presettable up-counter called the Error Register. The Error Register counts up at the same rate and in response to the same count signal as the Actual Count Register. During a Transfer signal which follows the Read signal, the complement of the first binary number is transferred from the Reference Count Register into the Error Register.

Abstract: A digital speed control system includes a first binary up-counter called an Actual Count Register. The Actual Count Register is initially reset to contain all "0"'s. During a sample time, an input is applied to the Actual Count Register so that it counts up to a first binary number during the sample time. The first binary number represents a reference speed. The system includes a Reference Count Register. In response to read and store command, the first binary number is loaded into the Reference Count Register, where it remains until the next request for a new reference speed. The system further includes a first binary presettable up-counter called the Error Register. The Error Register counts up at the same rate and in response to the same count signal as the Actual Count Register. During a Transfer signal which follows the Read signal, the complement of the first binary number is transferred from the Reference Count Register into the Error Register.

Abstract: A zener diode and resistor network is coupled to a single conductor by a switching device which, in combination with the network, produces a voltage on the conductor representative of one of four commands selected by the switching device. Another zener diode and resistor network is coupled to the receiving end of the transmission conductor and operates to generate two ternary signals which, in combination, are representative of the selected command. A plurality of dual-threshold CMOS logic gates generates four binary output signals responsive to the two ternary signals.