Data transmission system using analog to pulse width to digital conversion
First Claim
1. A data transmission system comprising:
- digital processor means for processing digital data to produce an output, said digital processor means further including means for periodically generating data request signals having a predetermined pulse duration indicative of a request for new digital data;
sensor means for generating analog data having a value indicative of a sensed condition;
sensor interface means powered by said data request signals for generating a ground signal a determinable time after the beginning of said data request signal in response to said analog data, said ground signal being a low impedance to ground and said determinable time between the beginning of said data request signal and said ground signal being indicative of the value of said analog data;
processor interface means, receiving said data request signals from said digital processor means and said ground signal from said sensor interface means for generating digital data indicative of said determinable time between the beginning of said data request signal and said ground signal;
said processor interface means further including means for gating said data request signals to said sensor interface means and means for transmitting said digital data to said digital processor means;
a single data transmission line interconnecting said sensor interface means and said processor interface means for transmitting said data request signal and said ground signal back and forth between said sensor interface means and said processor interface means.
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Abstract
A data transmission system using analog to pulse width to digital conversion for transmitting data generated by an analog sensor to a digital processor is disclosed. A data request signal generated by the digital processor is gated by a processor interface circuit along a single wire data transmission line to a remote sensor activating both the sensor and its associated interface electronics. The data request signal also provides electrical power to the sensor and sensor interface electronics eliminating the need for separate electrical power leads. The sensor interface electronics after a period of time determined by the value of the analog signal generated by the sensor generates a low impedance to ground signal on the data transmission line. The low impedance to ground signal is detected by the processor interface circuit which terminates the transmission of the data request signal. The processor interface circuit further includes a pulse width to digital converter generating digital data indicative of the duration the data request signal is transmitted. More than one sensor may interface the single data transmission line and each sensor interface may be individually activated by interrogation signals generated by the digital processor.
31 Citations
30 Claims
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1. A data transmission system comprising:
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digital processor means for processing digital data to produce an output, said digital processor means further including means for periodically generating data request signals having a predetermined pulse duration indicative of a request for new digital data; sensor means for generating analog data having a value indicative of a sensed condition; sensor interface means powered by said data request signals for generating a ground signal a determinable time after the beginning of said data request signal in response to said analog data, said ground signal being a low impedance to ground and said determinable time between the beginning of said data request signal and said ground signal being indicative of the value of said analog data; processor interface means, receiving said data request signals from said digital processor means and said ground signal from said sensor interface means for generating digital data indicative of said determinable time between the beginning of said data request signal and said ground signal;
said processor interface means further including means for gating said data request signals to said sensor interface means and means for transmitting said digital data to said digital processor means;a single data transmission line interconnecting said sensor interface means and said processor interface means for transmitting said data request signal and said ground signal back and forth between said sensor interface means and said processor interface means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A data transmission system for providing digital data to a digital processor having means for generating data request signals indicative of a request for new digital data, comprising:
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sensor means for generating analog data having a value indicative of a sensed condition; sensor interface means receiving said analog data and powered by said data request signals for generating a ground signal a determinable time after receiving said data request signal in response to said analog data, said ground signal being indicative of a low impedance to ground, and said determinable time between the beginning of said request signal and said ground signal being indicative of the value of said analog data; processor interface means receiving said data request signal from the digital processor and said ground signal from said sensor interface means for generating digital data indicative of said determinable time between the beginning of said data request signal and said ground signal;
said processor interface means further including means for gating said data request signals to said sensor interface means and means for transmitting said digital data to the digital processor; anda single data transmission line interconnecting said sensor interface means and said processor interface means for transmitting said data request signals and said ground signals back and forth between said sensor interface means and said processor interface means. - View Dependent Claims (16, 17, 18, 19, 20)
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21. In combination with a digital processor for processing digital data and sensor means generating analog data, wherein the digital processor includes means for generating data request signals requesting new input data and the sensor means generates analog data having a value indicative of sensed conditions, a data transmission system comprising:
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sensor interface means powered by said data request signals for generating a ground signal a determinable time after receiving said data request signal in response to said analog data, said ground signal being indicative of a low impedance to ground, and said determinable time between the beginning of said data request signal and said ground signal being indicative of the value of said received analog data; processor interface means, receiving said data request signal from the digital processor and said ground signal from said sensor interface means for generating digital data indicative of said determinable time between the beginning of said data request signal and said ground signal;
said processor interface means further including means for gating said data request signals to said sensor interface means and means for transmitting said digital data to the digital processor; anda single data transmission line interconnecting said sensor interface means and said processor interface means for transmitting said data request signals and said ground signals back and forth between said sensor interface means and said processor interface means. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. In combination with a digital processor for processing digital data to produce an output and a plurality of sensors generating output data indicative of sensed conditions, wherein said digital processor includes means for generating data request signals indicative of requests for new data from the sensor, each of such data request signals comprising an interrogation signal uniquely identifying the particular sensor from which new data is requested, followed by a data signal an improved data transmission system comprising:
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interrogation signal gate means sequentially receiving said interrogation and data signals from said digital processor for selectively transmitting only said interrogation signals, said interrogation signal gate means having a first state transmitting only said interrogation signals and switching to a second state in response to said data signal blocking the transmission of said subsequent data signals; data signal gate means sequentially receiving said interrogation signal and said data signals from the digital processor for selectively transmitting only said data signals, said data signal gate means having a first state in response to said interrogation signal blocking the transmission of said interrogation signals and switching to a second state in response to said data signal transmitting said data signals; amplifier means having an input and an output, said amplifier means receiving at said input the interrogation signals transmitted by the interrogation signal gate means and the data signal transmitted by the data gate means for amplifying and transmitting said interrogation and data signals via said output; line load detector means in circuit relationship with said amplifier means for generating a switch signal in response to a change in the impedance at the output of the amplifier means, said switch signal operative to switch said data signal gate means to said first state terminating the transmission of said data signal to said amplifier means; pulse width to digital converter means for generating digital data in response to the data signal transmitted by said data signal gate means; a single data transmission line connected to the output of said amplifier means for transmitting said interrogation and data signals; converter means powered by said data signal for generating a ground signal indicative of a low impedance to ground in response to the output data of said sensors at a time determinable from the value of said output data and wherein one converter means is associated with each of said plurality of sensors and is associated therewith; and decoder means connected to said single data transmission line for transmitting said data signal to said converter means in response to the interrogation signal uniquely identifying the sensor associated with said converter means, said decoder means further transmitting said ground signals generated by the converter means to the output of said amplifier means via said single data transmission line. - View Dependent Claims (29)
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30. A method for transmitting data between a digital processor and a plurality of sensors for generating sensor data indicative of sensed conditions, wherein said digital processor includes means for sequentially generating data request signals indicative of requests for new data from the sensors, wherein each of said data request signals comprises an interrogation signal uniquely identifying the particular sensor from which the new data is requested followed by a data signal, comprising the steps of:
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gating the data request signal generated by the digital processor with gate means to separately transmit the interrogation signal from the data signal; sequentially amplifying said interrogation and data signals to generate amplifier interrogation and data signals; detecting a change in the amplified data signal by means of a line load detector to generate a switch signal; deactivating said gate means with said switch signal to terminate the transmission of said data signal; gating clock pulses to a counter with said data signal to convert said data signals to digital data; transmitting said digital data to said digital processor in response to the termination of the transmission of said data signal; transmitting said amplified interrogation and data signals to remote decoder means via a single data transmission line; decoding said interrogation signal with said decoder means, to activate a switch transmitting said data signal to an associated converter means when the interrogation signal identifies the sensor associated with the decoder means; generating a ground signal by means of said converter means when the integrated value of the sensor data generated by the sensor associated therewith reaches a predetermined value, said ground signal indicative of a low impedance to ground, transmitting said ground signal back to said line load detector via said single data transmission line whereby said ground signal is detected by said line load detector which generates a switch signal terminating the transmission of said clock signal to said counter.
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Specification