Claims
- 1. A common bus multinode sensor system for at least one sensor providing a sensor signal, comprising:
- a power supply;
- a communication cable coupled to said power supply;
- remote sensor means, coupled between said cable and said sensor, for frequency division multiplexing the sensor signal onto said cable and receiving power from said cable, said remote sensor means comprising:
- programmable carrier frequency means for providing a carrier to said cable at a carrier frequency in dependence on an external input, said programmable carrier frequency means comprising:
- reference counter frequency means for providing a reference frequency;
- a counter counting in accordance with the external input and providing a divided count frequency;
- a phase/frequency comparator, operatively connected to said counter and said reference counter frequency means, for comprising the divided count frequency to the reference frequency and providing a voltage indicative of the comparison; and
- a voltage controlled oscillator, operatively connected to said counter and said cable, producing the carrier at a frequency dependent on the voltage; and
- modulation means for frequency modulating the carrier with the sensor signal; and
- receiver means, coupled to said cable, for demultiplexing the frequency division multiplexed sensor signal.
- 2. A system as recited in claim 1, wherein said modulation means comprises a filter having inputs operatively connected to said phase/frequency comparator and the sensor and an output operatively connected to said voltage controlled oscillator, for averaging the voltage produced by said phase/frequency comparator and for combining the averaged voltage with the sensor signal and providing the combination to said voltage controlled oscillator.
- 3. An analog serial bus interface integrated circuit couplable to sensors, a filter, an analog-to-digital converter and an oscillator reference, said circuit comprising:
- a counter receiving a frequency designation word applied to said circuit;
- a phase/frequency comparator connected to said counter;
- an oscillator connectable to said oscillator reference;
- a timing counter connected to said oscillator, said phase/frequency comparator and said analog-to-digital converter;
- an analog multiplexer connectable to the sensors and said analog-to-digital converter and connected to said timing counter;
- a shift register connected to said timing counter and said analog-to-digital converter;
- an encoder connected to said shift register and connectable to said filter; and
- a voltage controlled oscillator connected to said filter.
Parent Case Info
U.S. Pat. No. 4,770,842 issued Sept. 13, 1988.
US Referenced Citations (4)
Divisions (1)
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Number |
Date |
Country |
Parent |
934238 |
Nov 1986 |
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