MEASURING SIGNAL PROPAGATION AND ADJUSTABLE DELAYS IN ELECTRONIC DEVICES

Abstract

Systems and methods to measure signal propagation delay through objects. The system includes a controller, a single shot pulse generator, a first pulse/edge former, a multiplexer/demultiplexer, a second pulse/edge former, a timer, and a counter. The controller initializes the system, the clock and the counter. A pulse is sent from the single shot pulse generator to the first pulse/edge former. The pulse is propagated through the first pulse/edge former to the multiplexer, through a device under test, to the demultiplexer, and to the second pulse/edge former. The second pulse edge generator provides the pulse to the counter, which counts a predetermined number of pulses, and the clock, which measures the amount of time the counter counts the pulses. The propagation delay of the device under test is then calculated based on the counted number of pulses and the elapsed time measured by the clock.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited and other advantages and features of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a block diagram of an example system in accordance with the present invention;

FIG. 2 is a block diagram of an example computer system coupled to the system of FIG. 1;

FIG. 3 illustrates an example method of the present invention to measure propagation delay; and

FIG. 4 illustrates an alternative method of the present invention to measure propagation delay.

Claims

1. A system for measuring a signal propagation delay through a device, said system comprising: a controller;a single shot pulse generator electrically connected to said controller;a first pulse/edge former electrically connected to said controller and said single shot pulse generator, said first pulse/edge former receiving a signal from said single shot pulse generator;a second pulse/edge former;a multiplexer/demultiplexer configured to receive said signal from said first pulse/edge former, transmit said signal through said device, receive said signal from said device, and transmit said received signal to the second pulse/edge former, which transmits said signal back to said first pulse edge former;a timer; anda counter;wherein a plurality of said signals is transmitted through said device, wherein said counter counts a number of said plurality of signals, wherein said timer measures the elapsed time to transmit said number, and a system delay is calculated from said elapsed time and said number.

2. The system of claim 1, wherein said device is one of an electrical device, an electronic device and an opto-electronic device.

3. The system of claim 1, wherein said signal propagation delay is calculated by first removing said device from said system and using said elapsed time and said number to calculate a known delay for said system, and wherein said signal propagation delay is then calculated by subtracting said known delay from said system delay.

4. The system of claim 1, further comprising one or more fixed adjustable delays electrically connected to the multiplexer/demultiplexer, wherein each one of the one or more fixed adjustable delays has a different fixed adjustable delay.

5. The system of claim 4, wherein said signal propagation delay is calculated by transmitting a plurality of said signals through a first one of the fixed adjustable delays and using said elapsed time and said number to calculate a first propagation delay for said system, and by transmitting a plurality of said signals through a second one of the fixed adjustable delays and using said elapsed time and said number to calculate a second propagation delay for said system, and wherein a normalized signal propagation delay is then calculated by subtracting said first propagation delay for said system from said second propagation delay for said system.

6. The system of claim 1, further comprising fixed known delay circuitry electronically connected to the multiplexer/demultiplexer and to the first pulse/edge former, said fixed known delay circuitry providing a fixed known signal delay to said signal received from said first pulse/edge former and provided to said multiplexer/demultiplexer.

7. The system of claim 3, wherein said propagation delay is calculated to an accuracy within 1 picosecond.

8. The system of claim 3, wherein said number of iterations is greater than one hundred thousand iterations.

9. The system of claim 3, wherein said number of iterations is at least one hundred million iterations.

10. The system of claim 1, wherein said timer is a 0.001 millisecond step timer or less.

11. In a system for measuring a signal propagation delay through a device, said system comprising at least a clock, a counter, a multiplexer/demultiplexer, a single shot pulse generator, a first pulse/edge former, a second pulse/edge former, and a controller, a method for computing the signal propagation delay comprising: initializing the system with the controller;transmitting a pulse from the single shot pulse generator to the first pulse/edge former;sending said pulse from the first pulse/edge former to the multiplexer, through the device, to the demultiplexer and second pulse/edge former, and to the counter;causing the clock to begin measuring elapsed time;decrementing the counter one pulse count from a predetermined total number of pulses;repeating said transmitting, sending and decrementing until the counter decrements to zero; andcalculating a system delay based on the predetermined number of pulses and the elapsed time measured by the clock.

12. A method in accordance with claim 11, wherein initializing the system with the controller comprises: setting the clock to time zero;setting the counter to the predetermined number of pulses; andchanging the output level of the single shot pulse generator to cause the single shot pulse generator to begin transmitting the pulse to the first pulse/edge former.

13. A method in accordance with claim 11, wherein calculating the propagation delay comprises: removing said device from said system and using said elapsed time and said predetermined number of pulses to calculate a known delay for said system; andsubtracting the known delay from the system delay to calculate the propagation delay.

14. A method in accordance with claim 11, wherein the clock begins to measure elapsed time upon receiving a pulse from the second pulse/edge former; and the clock stops measuring elapsed time upon the counter decrementing to zero.

15. A method in accordance with claim 11, wherein the system further includes one or more fixed adjustable delays coupled to the device and the multiplexer/demultiplexer, the method further comprising: sending said pulse from the first pulse/edge former to the demultiplexer, through a first one of the one or more fixed adjustable delay, to the multiplexer and second pulse/edge former, and to the counter, decrementing the counter one pulse count from a predetermined total number of pulses, repeating said transmitting, sending and decrementing steps until the counter decrements to zero;determining a propagation delay for the first one of the one or more fixed adjustable delays;repeating the steps of sending and determining for every one of the one or more fixed adjustable delays;normalizing the determined propagation delays for the one or more fixed adjustable delays with reference to the shortest propagation delay; andgenerating a table comprising the normalized propagation delays for the one or more fixed adjustable delays.

16. A method in accordance with claim 13, wherein said propagation delay is calculated to an accuracy within 1 picosecond or less.

17. A method in accordance with claim 11, wherein said number of predetermined pulses is greater than one hundred thousand.

18. In a computerized system comprising a circuit board having electrical circuitry connecting a controller, a single shot pulse generator, a first pulse/edge former, a second pulse/edge former, a multiplexer/demultiplexer, a timer, a counter, a method of computing a signal propagation delay through a device comprising: initializing the controller, the timer, the counter, and the single shot pulse generator;transmitting a pulse from the single shot pulse generator to the first pulse/edge former;sending said pulse from the first pulse/edge former to the demultiplexer, through the device, to the multiplexer and the second pulse/edge former, and to the counter;causing the clock to begin measuring elapsed time;decrementing the counter one pulse count from a predetermined total number of pulses;repeating said transmitting, sending and decrementing steps until the counter decrements to zero; andcalculating a system delay based on the predetermined number of pulses and an elapsed time measured by the clock.

19. A method in accordance with claim 18, wherein calculating the propagation delay comprises: removing said device from said system and using said elapsed time and said predetermined number of pulses to calculate a known delay for said system; andsubtracting the known delay from the system delay to calculate the propagation delay.

20. A method in accordance with claim 18 wherein the system further includes a one or more fixed adjustable delays coupled to the device and the demultiplexer comprising a plurality of delay settings, wherein each one of the plurality of delay settings has a different known delay, the method further comprising: determining a propagation delay for every one of the one or more fixed adjustable delays by sending said pulse through every one of the one or more fixed adjustable delays;normalizing the determined propagation delays with reference to the shortest propagation delay; andgenerating a table comprising the normalized propagation delays for the one or more fixed adjustable delays.