Correlation of device-under-test orientations and radio frequency measurements
Antenna characterization systems and methods are described for hardware-timed testing of integrated circuits (IC) with integrated antennas configured for over-the-air transmission and/or reception. An IC to be tested (e.g., the device under test (DUT)) may be mounted to an adjustable positioner in an anechoic chamber. Radio frequency (RF) characteristics (e.g., including transmission characteristics, reception characteristics, and/or beamforming characteristics) of the IC may be tested over-the-air using an array of antennas or probes within the anechoic chamber while continually transitioning the adjustable positioner through a plurality of orientations. Counters and reference trigger intelligence may be employed to correlate measurement results with orientations of the DUT.
1. A system for correlating radio frequency (RF) measurements of a device-under-test (DUT) with orientations of the DUT, the system comprising:
a computer coupled to a non-transitory memory medium; and
a RF measurement system coupled to the computer,
wherein the computer is configured to transmit a sequence of acquisition triggers to the RF measurement system,
wherein, in response to receiving a first acquisition trigger of the sequence of acquisition triggers when the RF measurement system is not currently acquiring an RF measurement, the RF measurement system is configured to transmit a reference trigger to the computer, initiate the RF measurement of the DUT, and transmit a first result of the RF measurement to the computer,
wherein, in response to receiving a second acquisition trigger of the sequence of acquisition triggers when the RF measurement system is currently acquiring the RF measurement, the RF measurement system is configured to not transmit the reference trigger to the computer and not initiate the RF measurement of the DUT,
wherein the computer is further configured to:
receive the reference trigger and the first result from the RF measurement system; and
generate antenna characterization information of the DUT based on a correlation of the first result with a determined orientation of the DUT, wherein the orientation of the DUT is determined based at least in part on a value of one or more counters stored on the computer at the time when the reference trigger is received from the RF measurement system.
2. The system of claim 1 ,
wherein the one or more counters comprise a first counter corresponding to a first axis of rotation of the DUT and a second counter corresponding to a second axis of rotation of the DUT, and
wherein a value of the first counter at the time when the reference trigger is received is used to determine an angle of orientation of the DUT about the first axis and a value of the second counter at the time when the reference trigger is received is used to determine an angle of orientation of the DUT about the second axis.
3. The system of claim 2 ,
wherein the value of the first counter is modified in response to the DUT rotating about the first axis,
wherein the value of the second counter is modified in response to the DUT rotating about the second axis,
wherein the computer is further configured to:
count a number of times either of the first and second counters are modified; and
transmit an acquisition trigger of the sequence of acquisition triggers to the RF measurement system ever N th time either of the first and second counters are modified, wherein N is a positive integer.
4. The system of claim 1 ,
wherein the values of the one or more counters are modified in response to signals received from an adjustable positioner that orients the DUT, wherein the signals corresponding to each of the one or more counters are received on one or more channels.
5. The system of claim 4 ,
wherein the one or more channels comprise a first channel and a second channel of a quadrature encoder scheme,
wherein said modifying the values of the one or more counters comprises incrementing or decrementing the values of the one or more counters, and
wherein a relative phase between respective signals of the first channel and the second channel determines whether the counter apparatus increments or decrements the values of the one or more counters.
6. The system of claim 4 ,
wherein said modifying the values of the one or more counters comprises incrementing or decrementing the values of the one or more counters,
wherein the computer comprises an edge detector configured to detect the front edge in time of an incremented value of the one or more counters and the back edge in time of a decremented value of the one or more counters, and
wherein said transmitting by the computer of each acquisition trigger in the sequence of acquisition triggers to the RF measurement system is performed in response to the edge detector detecting the front edge of the incremented value of the one or more counters or the back edge of the decremented value of the one or more counters.
7. The ACS of claim 1 ,
wherein said acquiring a plurality of measurements of the DUT comprises measuring directional transmission properties of one or more antennas of the DUT at different orientations of the DUT.
8. The ACS of claim 1 ,
wherein said acquiring a plurality of measurements of the DUT comprises transmitting RF signals to the DUT within the chamber, and measuring directional reception properties of the RF signals by the DUT at different orientations of the DUT.
9. The ACS of claim 1 ,
wherein the antenna characterization information is usable to design antenna characteristics of the DUT.
10. A method for correlating radio frequency (RF) measurements of a device-under-test (DUT) with orientations of the DUT, the method comprising:
by a computer:
transmitting a sequence of acquisition triggers to an RF measurement system;
by the RF measurement system:
in response to receiving a first acquisition trigger of the sequence of acquisition triggers when the RF measurement system is not currently acquiring an RF measurement:
transmitting a reference trigger to the computer;
initiating the RF measurement of the DUT; and
transmitting a first result of the RF measurement to the computer;
in response to receiving a second acquisition trigger of the sequence of acquisition triggers when the RF measurement system is currently acquiring the RF measurement:
refrain from transmitting the reference trigger to the computer; and
refrain from initiating the RF measurement of the DUT; and
by the computer:
receiving the reference trigger and the first result from the RF measurement system; and
generating antenna characterization information of the DUT based on a correlation of the first result with a determined orientation of the DUT, wherein the orientation of the DUT is determined based at least in part on a value of one or more counters stored on the computer at the time when the reference trigger is received from the RF measurement system.
11. The method of claim 10 ,
wherein the one or more counters comprise a first counter corresponding to a first axis of rotation of the DUT and a second counter corresponding to a second axis of rotation of the DUT, and
wherein the method further comprises:
by the computer:
using a value of the first counter at the time when the reference trigger is received to determine an angle of orientation of the DUT about the first axis; and
using a value of the second counter at the time when the reference trigger is received to determine an angle of orientation of the DUT about the second axis.
12. The method of claim 11 ,
wherein the value of the first counter is modified in response to the DUT rotating about the first axis,
wherein the value of the second counter is modified in response to the DUT rotating about the second axis,
wherein the method further comprises:
by the computer:
counting a number of times either of the first and second counters are modified; and
transmitting an acquisition trigger of the sequence of acquisition triggers to the RF measurement system ever N th time either of the first and second counters are modified, wherein N is a positive integer.
13. The method of claim 10 , the method further comprising:
by the computer:
modifying the values of the one or more counters in response to signals received from an adjustable positioner that orients the DUT, wherein the signals corresponding to each of the one or more counters are received on one or more channels.
14. The method of claim 13 ,
wherein the one or more channels comprise a first channel and a second channel of a quadrature encoder scheme,
wherein said modifying the values of the one or more counters comprises incrementing or decrementing the values of the one or more counters, and
wherein a relative phase between respective signals of the first channel and the second channel determines whether the counter apparatus increments or decrements the values of the one or more counters.
15. The method of claim 13 ,
wherein said modifying the values of the one or more counters comprises incrementing or decrementing the values of the one or more counters, the method further comprising:
by the computer:
detecting the front edge in time of an incremented value of the one or more counters and the back edge in time of a decremented value of the one or more counters, and
wherein said transmitting by the computer of each acquisition trigger in the sequence of acquisition triggers to the RF measurement system is performed in response to the edge detector detecting the front edge of the incremented value of the one or more counters or the back edge of the decremented value of the one or more counters.
16. The method of claim 10 ,
wherein said acquiring a plurality of measurements of the DUT comprises measuring directional transmission properties of one or more antennas of the DUT at different orientations of the DUT.
17. The method of claim 10 ,
wherein said acquiring a plurality of measurements of the DUT comprises transmitting RF signals to the DUT within the chamber, and measuring directional reception properties of the RF signals by the DUT at different orientations of the DUT.
18. The method of claim 10 , the method further comprising:
using the antenna characterization information to design antenna characteristics of the DUT.
19. An antenna characterization system (ACS), comprising:
a chamber;
a counter apparatus;
a radio frequency (RF) signal analyzer coupled to one or more receive antennas and the counter apparatus, wherein the one or more receive antennas are positioned inside the chamber, wherein the RF signal analyzer is configured to acquire RF measurements made by the one or more receive antennas of transmissions of an antenna under test (AUT); and
an adjustable positioner coupled to the counter apparatus; and
a computer comprising a processor and coupled to each of the adjustable positioner, the counter apparatus, and the RF signal analyzer, wherein the computer is configured to:
initialize a measurement process on the AUT by causing the adjustable positioner to continually transition the AUT inside the chamber through a plurality of orientations without halting the motion of the adjustable positioner between orientations, wherein the adjustable positioner is configured to automatically transmit a signal through one or more channels to the counter apparatus in response to the adjustable positioner positioning the AUT according to each of the plurality of orientations,
wherein, in response to receiving the signals from the adjustable positioner through the one or more channels, the counter apparatus is configured to:
modify a first counter value;
transmit the modified first counter value to the computer; and
transmit a first acquisition trigger to the RF signal analyzer, wherein said modifying the first counter value, transmitting the modified first counter value, and transmitting the first acquisition trigger occur a plurality of times at different respective orientations of the AUT, and
wherein the RF signal analyzer is configured to acquire an RF measurement of transmissions of the AUT and relay the result of the RF measurement to the computer in response to receiving each of the plurality of first acquisition triggers, and
wherein the computer is further configured to:
correlate the modified first counter values received from the counter apparatus with the results of the RF measurements to determine an orientation of the plurality of orientations of the AUT corresponding to each of the results of the RF measurements; and
output a correlated list of results of the RF measurements and their respective orientations of the AUT.
20. The ACS of claim 19 ,
wherein, in response to receiving the signals from the adjustable positioner through the one or more channels, the counter apparatus is further configured to:
modify a second counter value;
transmit the modified second counter value to the computer; and
transmit a second acquisition trigger to the RF signal analyzer, wherein said modifying the second counter value, transmitting the modified second counter value, and transmitting the second acquisition trigger occur a plurality of times at different respective orientations of the AUT, and wherein the second counter value is associated with a different axis of rotation of the adjustable positioner than the first counter value.