Counter Enhancements for Improved Performance and Ease-of-Use

Patent metadata

Field	Value
Publication number	US-2016258990-A1
Application number	US-201514639432-A
Country	US
Kind code	A1
Filing date	Mar 5, 2015
Priority date	Mar 5, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

An improved counter may implement dynamic frequency measurement while also remaining fully backwards compatible with traditional frequency measurement methods. The counter may operate according to low-frequency, large range, and/or high frequency modes of operation. It may be programmable with a divisor value associated with the large range operating mode, and a measurement time associated with the high frequency mode of operation. The divisor and measurement time settings may be enabled or disabled, and when either setting is disabled, the counter becomes backwards compatible with traditional frequency measurement methods. The counter may also be provided with inputs representative of the desired type of measurement and the minimum and maximum expected values for the signal to be measured. The counter may perform the frequency measurement according to any one or more of the operating modes, and return a measurement result obtained in the operating mode that completes the measurement first.

First claim

We claim:

1 . A counter comprising:
a first input configured to receive a divisor value associated with a first method of operation; a second input configured to receive a measurement time value associated with a second method of operation; and counter circuitry configured to:
perform measurements on an input signal according to at least:
the first method of operation according to at least the divisor value; and
the second method of operation according to at least the measurement time value; and

return a measurement value obtained from whichever measurement of the measurements completes first.

2 . The counter of claim 1 , wherein the counter circuitry is further configured to:
for each present input period of the input signal:
if the present input period of the input signal is longer than a most recent previous input period of the input signal, continuously monitor the input signal for at least a first time period of specified length until an end of the present input period.

3 . The counter of claim 2 , wherein the counter circuitry is further configured to:
begin continuously monitoring the input signal during the present input period of the input signal from a point in time at which the present input period of the input signal has reached a duration commensurate with a duration of the most recent previous input period of the input signal.

4 . The counter of claim 1 , wherein the counter circuitry is further configured to measure an actual time required for input periods of the input signal to occur within a specified measurement time that corresponds to the measurement time value.

5 . The counter of claim 1 , wherein the counter circuitry is further configured to:
obtain a respective timestamp information with each measurement value; and use the respective timestamp information to obtain interpolated values in-between measurement values.

6 . The counter of claim 5 , wherein the timestamp information is indicative of a point in time to which the measurement value corresponds.

7 . The counter of claim 1 , further comprising one or more of:
a third input configured to receive measurement type value indicative of a desired type of measurement; a fourth input configured to receive minimum and maximum expected values for a signal to be measured; or a fifth input configured to receive measurement sample clock timing information.

8 . A method for performing measurements, the method comprising:
receiving, at a counting device, a divisor value associated with a first type of operation; receiving, at the counting device, a measurement time value associated with a second type of operation; performing, by the counting device, measurements for an input signal according to at least:
the first type of operation according to the divisor value; and
the second type of operation according to the measurement time value; and
returning a measurement value obtained from whichever measurement of the measurements completes first.

9 . The method of claim 8 , further comprising:
for each present input period of the input signal:
continuously monitoring the input signal for at least a first time period of specified length until an end of the present input period of the input signal if the present input period of the input signal is longer than a most recent previous input period of the input signal.

10 . The method of claim 9 , wherein said continuously monitoring the input signal comprises:
beginning to continuously monitor the input signal during the present input period of the input signal from a point in time at which the present input period of the input signal has reached a duration commensurate with a duration of the most recent previous input period of the input signal.

11 . The method of claim 8 , further comprising measuring an actual time required for input periods of the input signal to occur within a specified measurement time that corresponds to the measurement time value.

12 . The method of claim 11 further comprising:
obtaining a respective timestamp information with each count value; and
interpolating values in-between count values according to at least the respective timestamp information.

13 . The method of claim 12 , wherein the timestamp information is indicative of a point in time to which the count value corresponds.

14 . The method of claim 8 , further comprising at least one of:
receiving, at the counting device, a measurement type value indicative of a desired type of measurement; receiving, at the counting device, minimum and maximum expected values for a signal to be measured; receiving, at the counting device, sample clock timing information representing a rate at which the measurements are to be sampled; and wherein said performing the measurements comprises performing the measurements according to at least:
the received measurement type when receiving the measurement type;
the received minimum and maximum expected values when receiving the minimum and maximum expected values; or
the received sample clock timing information when receiving the sample clock information.

15 . A measurement system comprising:
a first device configured to perform a specified function; a monitoring device configured to provide a feedback signal from the first device, wherein the feedback signal is indicative of an operating characteristic of the first device; and a counter configured to:
receive a divisor value associated with a first method of operation;
receive a measurement time value associated with a second method of operation;
perform measurements on the feedback signal according to at least:
the first method of operation according to the divisor value; and
the second method of operation according to the measurement time value; and

return a measurement value obtained from whichever measurement of the measurements completes first.

16 . The measurement system of claim 15 , wherein the counter is further configured to:
for each present input period of the feedback signal:
if the present input period of the feedback signal is longer than a most recent previous input period of the feedback signal, continuously monitor the feedback signal for at least a first time period of specified length until an end of the present input period of the feedback signal.

17 . The measurement system of claim 16 , wherein the counter is further configured to:
begin continuously monitoring the feedback signal during the present input period of the feedback signal from a point in time at which the present input period of the feedback signal has reached a duration commensurate with a duration of the most recent previous input period of the feedback signal.

18 . The measurement system of claim 15 , wherein the counter is further configured to measure an actual time required for input periods of the feedback signal to occur within a specified measurement time that corresponds to the measurement time value.

19 . The measurement system of claim 15 , wherein the counter is further configured to:
obtain a respective timestamp information with each measurement value, wherein the timestamp information is indicative of a point in time to which the counter sample value corresponds; and interpolate values in-between measurement values according to the respective timestamp information.

20 . The measurement system of claim 15 , wherein the counter is further configured to:
receive measurement type value indicative of a desired type of measurem

Assignees

• Nat Instr Corp

Inventors

• Dewhirst Adam H
• Yap Chee Fai

Classifications

• H03K21/40

  Monitoring; Error detection; Preventing or correcting improper counter operation · CPC title

• H03K21/023

  comprising pulse shaping or differentiating circuits · CPC title

• G01P3/486

  delivered by photo-electric detectors · CPC title

• G01R23/02 Primary

  Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage · CPC title