Abstract: A verification and monitoring system for signal and status indicators and voice and metering features which is particularly suited for a taxi cab is disclosed. The operational status of the indicators are initially verified each time the ignition system of an associated taxi cab is energized. The verification circuit detects the failure of individual indicators even though a plurality of indicators may serve as a single visual display. The voice and metering features are continuously verified.

Abstract: A matter sensing apparatus includes a piezoelectric transducer, having a face susceptible to matter accretions at a surface for which matter accretion detection is desired. The electrical circuit of the transducer is coupled in the feedback path of an amplifier to establish an oscillator that oscillates at frequencies determined by the resonant frequency of the transducer and the loading on its face. The oscillator signals are converted to binary signals and utilized with binary signals, provided by a thermostat, that a representative of temperatures above or below a selected temperature to provide signals indicative of whether ice or other matter has accredited on the surface.

Abstract: A circuit is shown for use within an optical scanning system utilizing at least two scanning beams for scanning a grating and a document. A high frequency reference signal is applied to a counter which also receives the grating signal. The grating signal is delayed by a counter to assure that the grating signal has been synchronized with the reference signal. As the scan across the document hits a reference target, a picture element signal is generated which is also applied to the counter. The counter is enabled upon receipt of a positive going signal from both the reference signal and the picture element reference signal. As the reference signal is a much higher frequency than the picture element signal, any error in misalignment between the grating whose signal is synchronized with the reference signal and the target is eliminated by the high frequency reference signal. A further delay counter within the circuit eliminates errors caused by the width of the target signal.

Abstract: An angle position transducer is shown which is utilized within an optical scanning system that projects a rotating beam of light from a single point and reflects that light from a radial reflector back toward the point. The transducer includes a wedge shaped mask which is arranged between a pair of photodetectors mounted to the left and right of the mask. A second mask limits the amount of light which lands upon the photodetectors during the extreme left or right-hand rotation of the light beam. The output of the photodetectors is combined in an add and subtract circuit to produce a linear output signal which indicates the position of the rotating light beam from its far right to its far left-hand rotational position.

Abstract: In an optical scanning system the position of a scanning beam is determined by a grating across which the beam is traced and then retraced to start again. The first grate is detected by first filtering the relatively low frequency input signals generated as the beam traces across the grating and the relatively high frequency signals generated as the beam retraces across the grating. The filter passes the low frequency signals, excludes the high frequency signals and accentuates the changes between high and low frequency signals which occur as the beam reaches either end of the grating. By applying the filtered signal to a gating arrangement, it is possible to eliminate one plurality of the signals generated as the beam falls upon the end of the grating. The remaining plurality of signals is further applied to a gate which detects the first grate signal to the exclusion of all others for providing an accurate indication of the start of scan of the optical system.

Abstract: A circuit for producing an output pulse of predetermined amplitude and a width equal to the mid amplitude width of an input pulse from an electro-optical label reading system is provided. The present circuit comprises delay line means having a first output terminal and a second output terminal with the signal at the second output terminal being delayed twice the time of the delay at the first terminal. The first output terminal of the delay line is connected to an amplifier operative to double the amplitude of the signal applied thereto. The output of the amplifier is connected to one input of each of first and second comparators with the other input to the comparators respectively connected to the input signal source and the second terminal of the delay line. The output of the comparators is connected to the input to an AND gate with the output from the AND gate providing the desired pulse width information.

Abstract: A system is provided for time multiplexing a plurality of optical scanners. The system includes at least two electro-optical detection systems, each including means for receiving an image of an object and producing an electrical signal output in response to the sensing of an image, mirror means movable to scan a first location and reflect an image of any object at the first location to the first detection system and to scan a second location to reflect an image of any object at the second location to the second detection system and means for moving the mirror to continuously scan the first and second locations. The system further includes means for processing the electrical signal outputs of the detection system and switch means for alternately connecting the outputs of the first and second detection system to the processing means.