Patent
Test and measurement instrument and method of calibrating
| العنوان: | Test and measurement instrument and method of calibrating |
|---|---|
| Patent Number: | 8,103,473 |
| تاريخ النشر: | January 24, 2012 |
| Appl. No: | 12/251747 |
| Application Filed: | October 15, 2008 |
| مستخلص: | A test and measurement instrument and a method of calibrating the test and measurement instrument including a reference signal generator; multiple input channels; and multiple input circuits. Each input channel is coupled to a corresponding input circuit; and one of the input circuits is coupled to the reference signal generator. |
| Inventors: | Acuff, Ronald A. (Portland, OR, US); Larson, Lester L. (Portland, OR, US); Cosgrove, Kevin E. (Portland, OR, US) |
| Assignees: | Tektronix, Inc. (Beaverton, OR, US) |
| Claim: | 1. A test and measurement instrument, comprising: a reference signal generator; a plurality of input channels; and a plurality of input circuits; wherein: each input channel is coupled to a corresponding input circuit; and one of the input circuits is coupled to an output of the reference signal generator; and further comprising: a calibration port coupled to the output of the reference signal generator; wherein the reference signal generator is configured to output a reference signal to both the calibration port and the input circuit coupled to the reference signal generator. |
| Claim: | 2. The test and measurement instrument of claim 1 , further comprising a controller configured to determine a transition region of an input signal received through one of the input channels relative to the reference signal. |
| Claim: | 3. The test and measurement instrument of claim 2 , wherein the controller is further configured to determine samples of the input signal relative to the reference signal that are unstable. |
| Claim: | 4. The test and measurement instrument of claim 1 , wherein the controller is configured to determine at least one of a setup time and a hold time for one of the input circuits in response to the unstable samples associated with that input circuit. |
| Claim: | 5. The test and measurement instrument of claim 1 , further comprising: a controller configured to determine transition regions of a plurality of input signals received through the input channels relative to the reference signal wherein the controller is further configured to determine a relative timing between transition regions of the input signals. |
| Claim: | 6. The test and measurement instrument of claim 5 , wherein the controller is configured to deskew the input circuits in response to the relative timing. |
| Claim: | 7. The test and measurement instrument of claim 1 , wherein: the input circuits are grouped into a plurality of input blocks, each input block corresponding to one of the ports; and at least one input block includes a number of input circuits greater than a number of channels of the corresponding port. |
| Claim: | 8. The test and measurement instrument of claim 7 , wherein at least one of the input blocks includes the input circuit coupled to the reference signal generator. |
| Claim: | 9. A method of calibrating a test and measurement instrument, comprising: generating a reference signal in the test and measurement instrument; receiving the reference signal in a first input circuit; outputting the reference signal; receiving the outputted reference signal in a second input circuit; and sampling the reference signal received by the second input circuit in response to the reference signal received by the first input circuit determining unstable samples of the sampled reference signal received by the second input circuit; and determining at least one of a setup time and a hold time for the second input circuit in response to the unstable samples. |
| Claim: | 10. The method of claim 9 , further comprising: oversampling the received reference signal relative to a plurality of transitions of the reference signal received in the first input circuit; and combining portions of the oversampled reference signal according to the transitions of the reference signal received in the first input circuit. |
| Claim: | 11. The method of claim 10 , further comprising: for each transition of the plurality of transitions of the reference signal received in the first input circuit, oversampling the received reference signal; and determining a position relative to the reference signal as an unstable sample if a value of the sample in the same position relative to the reference signal changes with respect to the plurality of transitions of the reference signal. |
| Claim: | 12. The method of claim 9 , further comprising substantially simultaneously determining unstable samples of all input circuits of the test and measurement instrument that are coupled to an external port. |
| Claim: | 13. The method of claim 9 , further comprising: receiving the outputted reference signal in a third input circuit; determining unstable samples of the sampled reference signal received by the third input circuit; and determining a skew between the second input circuit and the third input circuit in response to the unstable samples of the second input circuit and the unstable samples of the third input circuit. |
| Claim: | 14. A test and measurement instrument, comprising: a plurality of input channels, each input channel to receive a corresponding input signal; an oversampler to oversample each input signal; for each oversampled input signal, a plurality of sample point select circuits, each sample point select circuit to select a sample of corresponding oversampled input signal as an output sample; and a cross-point switch to route the output samples of the sample point select circuits to a plurality of output channels; and further comprising: a plurality of comparators corresponding to the input channels; and a plurality of threshold voltage circuits, each threshold voltage circuit configured to provide a threshold voltage to a corresponding one of the comparators; wherein each threshold voltage is independently controllable. |
| Claim: | 15. The test and measurement instrument of claim 14 , further comprising: trigger circuitry to trigger an operation of the test and measurement instrument; wherein: the trigger circuitry is coupled to one of the output channels; and the cross-point switch is configured to route any of the output samples of the sample point select circuits to the output channel coupled to the trigger circuitry. |
| Claim: | 16. The test and measurement instrument of claim 14 , further comprising: a controller configured to generate a plurality of sample point select signals; wherein each sample point select circuit is configured to select the sample of the oversampled input signal in response to a corresponding subset of the sample point select signals. |
| Current U.S. Class: | 702/107 |
| Patent References Cited: | 6615073 September 2003 Panescu et al. |
| Primary Examiner: | Le, John H |
| Attorney, Agent or Firm: | Meeker, Derek Lenihan, Thomas F. |
| رقم الانضمام: | edspgr.08103473 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |