1. A probe for a test instrument, the probe comprising:
a probe tip;
a probe housing; and
an attenuator circuit within the probe housing, the attenuator circuit being electrically coupled to the probe tip to receive a signal therefrom, the attenuator circuit including:
a plurality of first micromachined switches, each of the plurality of first micromachined switches being capable of being in one of at least two states; and
a plurality of attenuators electrically coupled to the plurality of first micromachined switches, such that the signal is attenuated by an amount based on the states of the first micromachined switches.
2. The probe of claim 1, wherein the plurality of first micromachined switches and the plurality of attenuators are fabricated on a common substrate.
3. The probe of claim 1, wherein the plurality of attenuators includes a plurality of resistors.
4. The probe of claim 1, further comprising a digitization circuit within the probe housing and electrically coupled to the attenuation circuit, the digitization circuit including an analog-to-digital converter and operative to provide digital data about the signal.
5. The probe of claim 4, further comprising a probe lead, the probe lead including: a power lead, a ground lead and a signal lead; wherein the digitization circuit is operative to send the digitized data about the signal via the signal lead.
6. The probe of claim 5, wherein the signal lead comprises an electrically conductive wire.
7. The probe of claim 5, wherein the signal lead comprises an optical fiber.
8. The probe of claim 1, further comprising a compensation circuit within the probe housing and electrically coupled to the attenuation circuit, the compensation circuit including:
a plurality of second micromachined switches, each of the plurality of second micromachined switches being capable of being in one of at least two states; and
a plurality of reactive elements electrically coupled to the plurality of second micromachined switches, such that a total amount of reactance connected to the attenuation circuit is based on the states of the second micromachined switches.
9. The probe of claim 8, wherein the plurality of reactive elements includes a plurality of capacitors.
10. The probe of claim 8, further comprising a reference signal source within the probe housing and electrically coupled to the attenuation circuit.
11. The probe of claim 10, further comprising a third micromachined switch within the probe housing and electrically coupled between the reference signal source and the attenuation circuit.
12. The probe of claim 10, further comprising a third micromachined switch within the probe housing and electrically coupled between the probe tip and the attenuation circuit.
13. The probe of claim 10, further comprising a control circuit within the probe housing, coupled to the compensation circuit and operative to automatically activate a selected set of the second micromachined switches.
14. The probe of claim 8, further comprising:
a probe lead; and
a third micromachined switch within the probe housing and electrically coupled to the attenuation circuit and operative to receive a reference signal via the probe lead and provide the reference signal to the attenuation circuit.
15. The probe of claim 1, further comprising:
a second micromachined switch within the probe housing; and
a reference signal source within the probe housing and electrically coupled to the attenuation circuit via the second micromachined switch.
16. A probe for a test instrument, the probe comprising:
a probe tip;
a probe housing; and
a compensation circuit within the probe housing and electrically coupled to the probe tip, the compensation circuit including:
a plurality of micromachined switches, each of the plurality of micromachined switches being capable of being in one of at least two states; and
a plurality of reactive elements electrically coupled to the plurality of micromachined switches, such that a total amount of reactance connected to the probe tip is based on the states of the micromachined switches.
17. The probe of claim 16, further comprising a reference signal source within the probe housing and electrically coupled to the compensation circuit.
18. The probe of claim 17, further comprising a second micromachined switch within the probe housing and electrically coupled between the reference signal source and the compensation circuit.
19. The probe of claim 17, further comprising a second micromachined switch within the probe housing and electrically coupled between the probe tip and the compensation circuit.
20. The probe of claim 16, further comprising a control circuit within the probe housing and coupled to the compensation circuit and operative to automatically activate a selected set of the second micromachined switches.
21. The probe of claim 16, further comprising:
a probe lead; and
a second micromachined switch within the probe housing and electrically coupled to the compensation circuit and operative to receive a reference signal via the probe lead and provide the reference signal to the compensation circuit.
22. A method of automatically adjusting a probe connected to a test instrument, the probe having a housing, the method comprising:
providing a plurality of micromachined switches within the probe housing, each of the plurality of micromachined switches being capable of being in one of at least two states;
providing a plurality of reactive elements within the probe housing, the plurality of reactive elements being electrically coupled to the plurality of micromachined switches, such that a total amount of reactance is provided based on the states of the micromachined switches; and
automatically setting the states of the micromachined switches, such that a desired total amount of reactance is provided by the plurality of reactive elements.
23. The method of claim 22, further comprising:
providing a reference signal; and
analyzing a signal resulting from an interaction between the reference signal and at least some of the plurality of reactive elements;
wherein automatically setting the states of the micromachined switches comprises setting the states of the switches in response to analyzing the resulting signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A data storage device comprising:
a disk comprising at least one servo seed pattern;
a head actuated over the disk; and
control circuitry configured to:
generate an amplitude measurement based on a read signal emanating from the head while reading the disk;
first count a number of times the amplitude measurement exceeds a first threshold during a first revolution of the disk;
second count a number of times the amplitude measurement exceeds the first threshold during a second revolution of the disk; and
detect the servo seed pattern based on the first count and the second count.
2. The data storage device as recited in claim 1, wherein when a first delta between the first count and the second count is greater than a second threshold, the control circuitry is further configured to:
adjust a gain of the read signal; and
detect the servo seed pattern based on the adjusted gain of the read signal.
3. The data storage device as recited in claim 2, wherein prior to detecting the servo seed pattern the control circuitry is further configured to:
third count a number of times the amplitude measurement exceeds the first threshold during a third revolution of the disk;
fourth count a number of times the amplitude measurement exceeds the first threshold during a fourth revolution of the disk; and
validate the adjusted gain of the read signal when a second delta between the third count and the fourth count is less than the second threshold.
4. The data storage device as recited in claim 3, wherein the control circuitry is further configured to continue adjusting the gain of the read signal until the delta is less than the second threshold.
5. The data storage device as recited in claim 1, wherein when a first delta between the first count and the second count is greater than a second threshold, the control circuitry is further configured to:
adjust the first threshold; and
detect the servo seed pattern based on the adjusted first threshold.
6. The data storage device as recited in claim 5, wherein prior to detecting the servo seed pattern the control circuitry is further configured to:
third count a number of times the amplitude measurement exceeds the first threshold during a third revolution of the disk;
fourth count a number of times the amplitude measurement exceeds the first threshold during a fourth revolution of the disk; and
validate the adjusted first threshold when a second delta between the third count and the fourth count is less than the second threshold.
7. The data storage device as recited in claim 6, wherein the control circuitry is further configured to continue adjusting the first threshold until the delta is less than the second threshold.
8. The data storage device as recited in claim 1, wherein the control circuitry is further configured to detect the servo seed pattern by opening a servo seed pattern window based on when the amplitude measurement exceeds the first threshold relative to a rotation angle of the disk.
9. The data storage device as recited in claim 8, wherein the control circuitry is further configured to open the servo seed pattern window based on when the amplitude measurement exceeds the first threshold during the first disk revolution and when the amplitude measurement exceeds the first threshold during the second disk revolution at the same rotation angle of the disk.
10. A method of operating a data storage device, the method comprising:
generating an amplitude measurement based on a read signal emanating from a head while reading a disk;
first counting a number of times the amplitude measurement exceeds a first threshold during a first revolution of the disk;
second counting a number of times the amplitude measurement exceeds the first threshold during a second revolution of the disk; and
detecting a servo seed pattern on the disk based on the first count and the second count.
11. The method as recited in claim 10, wherein when a first delta between the first count and the second count is greater than a second threshold, the method further comprises:
adjusting a gain of the read signal; and
detecting the servo seed pattern based on the adjusted gain of the read signal.
12. The method as recited in claim 11, wherein prior to detecting the servo seed pattern the method further comprises:
third counting a number of times the amplitude measurement exceeds the first threshold during a third revolution of the disk;
fourth counting a number of times the amplitude measurement exceeds the first threshold during a fourth revolution of the disk; and
validating the adjusted gain of the read signal when a second delta between the third count and the fourth count is less than the second threshold.
13. The method as recited in claim 12, further comprising to continue adjusting the gain of the read signal until the delta is less than the second threshold.
14. The method as recited in claim 10, wherein when a first delta between the first count and the second count is greater than a second threshold, the method further comprises:
adjusting the first threshold; and
detecting the servo seed pattern based on the adjusted first threshold.
15. The method as recited in claim 14, wherein prior to detecting the servo seed pattern the method further comprises:
third counting a number of times the amplitude measurement exceeds the first threshold during a third revolution of the disk;
fourth counting a number of times the amplitude measurement exceeds the first threshold during a fourth revolution of the disk; and
validating the adjusted first threshold when a second delta between the third count and the fourth count is less than the second threshold.
16. The method as recited in claim 15, further comprising to continue adjusting the first threshold until the delta is less than the second threshold.
17. The method as recited in claim 10, further comprising detecting the servo seed pattern by opening a servo seed pattern window based on when the amplitude measurement exceeds the first threshold relative to a rotation angle of the disk.
18. The method as recited in claim 17, further comprising opening the servo seed pattern window based on when the amplitude measurement exceeds the first threshold during the first disk revolution and when the amplitude measurement exceeds the first threshold during the second disk revolution at the same rotation angle of the disk.