Duty cycle-based bit interface system

• US 9,802,718 B2
• Filed: 10/01/2015
• Issued: 10/31/2017
• Est. Priority Date: 10/01/2015
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Golden, Brian R.
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): Kong, Sze-Hon
• Application Number:
  US14/872,538
• Publication Number:
  US 20170096239A1
• Time in Patent Office: 761 Days
• CPC Class Codes: B64F 5/40 Maintaining or repairing aircraft
• CPC Class Codes: B64F 5/60 Testing or inspecting aircraft components or systems
• CPC Class Codes: G01R 29/0273 the pulse characteristic being duration, i.e. width (indicating that frequency of pulses is above or below a certain limit)
• CPC Class Codes: G01R 31/005 Testing of electric installations on transport means
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/008 on air- or spacecraft, railway rolling stock or sea-going vessels
• CPC Class Codes: H03K 5/26 the characteristic being duration, interval, position, frequency, or sequence

Abstract

A duty cycle-based bit interface system includes a first stage voltage converter and second stage voltage converter in signal communication with the first stage voltage converter. The first stage voltage converter converts a digital voltage signal into an analog voltage signal. The second stage voltage converters convert the digital voltage signal into a scaled version of the same. A sampling unit is in signal communication with at least one of the second stage voltage converters, and is configured to sample a portion of the first stage analog output voltage signal during a sampling time period. The sampled portion has a duty cycle based-analog voltage signal during the sampling time period. A bit selector unit is in signal communication with the sampling unit, and outputs a bit enable signal that initiates a specific diagnostic test among a plurality of diagnostic tests based on the duty cycle of the sampled portion.

Claims

1. A duty cycle-based bit interface system, comprising:

a first stage voltage converter unit in signal communication with a digital signal source, the first stage voltage converter configured to convert a digital voltage signal into an analog voltage signal;

a plurality of second stage voltage converters in signal communication with the first stage voltage converter;

the second stage voltage converters configured to convert the digital voltage signal into a scaled version of the same;

an electronic sampling unit in signal communication with at least one of the second stage voltage converters, the sampling unit configured to sample a portion of the first stage analog output voltage signal during a sampling time period, the sampled portion having a duty cycle based-analog voltage signal during the sampling time period; and

an electronic bit selector unit in signal communication with the sampling unit, the bit selector unit configured to output a bit enable signal that initiates a specific diagnostic test among a plurality of diagnostic tests based on the duty cycle of the sampled portion.

2. The duty cycle-based bit interface system of claim 1, wherein at least one component of a vehicle is actuated in response to the bit enable signal so as to execute the specific diagnostic test.

3. The duty cycle-based bit interface system of claim 1, wherein the electronic bit selector unit outputs the bit enable signal based on a comparison between the duty cycle-based analog voltage signal of the sampled portion and a plurality of threshold duty cycle ranges.

4. The duty cycle-based bit interface system of claim 3, wherein each threshold duty cycle range corresponds to a specific diagnostic test among a plurality of different diagnostic tests.

5. The duty cycle-based bit interface system of claim 4, wherein the sampling unit comprises:

a first timing circuit that is initiated in response to a transition from one of the second stage voltage signals;

a second timing circuit that defines the sampling time period and outputs the sampled portion of the first stage analog output voltage signal to the bit selector unit; and

a third timing circuit that sets an overall time period and allows retriggering of the first timing circuit when the overall time period expires.

6. The duty cycle-based bit interface system of claim 5, wherein the bit selector unit comprises:

a first stage digital-to-analog converter in signal communication with the digital signal source and configured to generate an analog signal based on a duty cycle; and

a duty cycle threshold generator circuit in signal communication with a power supply of the first stage digital-to-analog converter and is configured to divide a reference voltage signal into the plurality of threshold duty cycle ranges.

7. The duty cycle-based bit interface system of claim 6, wherein the first stage voltage converter unit includes a digital-to-analog converter configured to convert the digital voltage signal into the analog voltage signal.

8. The duty cycle-based bit interface system of claim 7, wherein the first voltage signal is a digital signal having a fixed frequency and a varying duty cycle, and the second voltage signal is an analog signal.

9. The duty cycle-based bit interface system of claim 7, wherein the digital signal source includes a pulse width modulation (PWM) circuit that generates an input to the first stage voltage signal.

10. The duty cycle-based bit interface system of claim 9, further comprising a second stage signal converter in signal communication with the first stage converter and configured to convert a digital signal having variable frequency and fixed duty cycle into a scaled version of the same that initiates a frequency over/under diagnostic test.

11. A method of controlling a duty cycle-based bit interface system, the method comprising:

converting a first stage voltage signal into a second stage voltage signal;

sampling a duty cycle-based analog output from a portion of a digital-to analog converted (DAC) signal from the first stage voltage signal during a sampling time period; and

outputting a bit enable signal that initiates a specific diagnostic test among a plurality of diagnostic tests based on the duty cycle of the sampled portion.

12. The method of claim 11, further comprising diagnosing operation of a mechanical component included in a vehicle according to the specific diagnostic test in response to outputting the bit enable signal.

13. The method of claim 11, further comprising outputting the bit enable signal in response to a comparison between a duty cycle-based analog voltage signal of the sampled portion and a plurality of threshold duty cycle ranges.

14. The method of claim 13, further comprising assigning each threshold duty cycle range to a specific diagnostic test among a plurality of different diagnostic tests.

15. The method of claim 14, wherein sampling the duty cycle-based analog voltage signal further comprises:

initiating a first timer configured to provide a first time period that encompasses the duty cycle-based analog voltage signal charge period;

in response to expiration of the first time period, triggering a second timer that utilizes the sampled portion of the duty cycle-based analog voltage signal to select a logically determined test during the sampling time period;

disabling retriggering of the first timer circuit while utilizing the sampled portion; and

outputting the trigger control signal to the first timer circuit when the time period expires so as to ready the duty cycle-based bit interface system so as to receive a next commanded test.

16. The method of claim 15, wherein outputting a bit enable signal further comprises:

generating an analog signal based on a duty cycle; and

dividing a voltage reference into the plurality of threshold duty cycle ranges.

17. The method of 16, wherein converting the first stage voltage signal into the second stage voltage signal includes converting a digital voltage signal into a scaled version of the same.

18. The method of claim 17, wherein the first stage digital voltage signal has a fixed frequency and a varying duty cycle.

19. The method of claim 17, wherein generating the first stage digital voltage signal include generating a pulse-width modulated square wave.

20. The method of claim 19, further comprising:

converting a second stage digital signal having variable frequency and fixed duty cycle into a scaled version of the same; and

initiating a frequency over/under diagnostic test based on the second stage digital voltage signal.