Abstract: An occupancy sensor that provides improved performance by the inclusion of a microprocessor that controls the sensing transducers and processes the received signal to optimize desired detection performance. The occupancy sensor includes a quadrature detection technique and automatic sensitivity adjustment that reduce false detection caused by air flow, hallway traffic and other noise sources. A fault detection method executed periodically detects fault conditions in the sensor or sensing area caused by component failure or obstructions in front of the sensor. Transmitter power is varied depending on the size of the desired coverage area. Since various ambient parameters such as line voltage, light level, and temperature may be easily and usefully monitored, the microprocessor may use these variables to make intelligent decisions in controlling electrical loads, such as building lighting and ventilation.

Abstract: A vocal frequency suppression apparatus for suppressing selected portions of a vocal signal to prevent inadvertent control of components controlled by dual tone multi-frequency ("DTMF") codes. The vocal frequency suppression apparatus includes a DTMF code generator having a plurality of user-selectable switches. The apparatus further produces a vocal signal which may contain vocal frequencies which correspond to at least one frequency of at least one of the DTMF codes. The apparatus includes a device for suppressing one or more of the vocal frequencies which correspond to frequencies found in the DTMF codes to prevent inadvertent control of any DTMF controlled components by the vocal signal. The suppression device is operably located between the producing device and the DTMF generator.