SIMULTANEOUS SENSITIVITY TESTING FOR MULTIPLE DEVICES IN RADIO-FREQUENCY TEST SYSTEMS

• US 20120231745A1
• Filed: 03/10/2011
• Published: 09/13/2012
• Est. Priority Date: 03/10/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Gregg, Justin, Syed, Adil, Venkataraman, Vishwanath
• Granted Patent: US 8,600,311 B2
• Time in Patent Office: Days
• US Class Current: 455/67.12
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 52/143 Downlink power control

Abstract

A test station may include a test host, a signal generator, and a test chamber. Multiple devices under test (DUTs) may be placed in the test chamber during device characterization operations. Radio-frequency signals may be conveyed from the signal generator to the multiple DUTs using a radiated arrangement through an antenna in the test chamber. The signal generator may broadcast downlink test signals. The DUTs may synchronize with the downlink test signals and measure radio-frequency performance levels while receiving the downlink test signals. The test host may direct the signal generator to gradually lower its output power level. The DUTs may be used to determine downlink sensitivity by monitoring the measured radio-frequency performance levels as the output power level of the signal generator is lowered. Downlink sensitivity testing may be performed across any desired radio-frequency bands and channels.

Claims

1. A method of performing downlink sensitivity testing on a plurality of devices under test with a test station, wherein the test station includes a tester and a test chamber in which the plurality of devices under test are tested, the method comprising:

directing the tester to wirelessly broadcast initialization signals in a radio-frequency channel to each of the plurality of devices under test.

2. The method defined in claim 1, further comprising:

with the tester, wirelessly broadcasting test signals to each of the plurality of devices under test at a first output power level in the radio-frequency channel.

3. The method defined in claim 2, further comprising:

after using the tester to broadcast the test signals at the first output power level for a given period of time during which each of the plurality of devices under test receives the test signals and measures a corresponding receive power level for the test signals, directing the tester to broadcast test signals to the plurality of devices under test at a second output power level that is lower than the first output power level in the radio-frequency channel.

4. The method defined in claim 2, further comprising:

after using the tester to broadcast the test signals at the first output power level for a given period of time during which each of the plurality of devices under test receives the test signals and measures a plurality of corresponding radio-frequency performance metrics for the test signals, directing the tester to broadcast test signals to the plurality of devices under test at a second output power level that is different from the first output power level in the radio-frequency channel, wherein the plurality of radio-frequency performance metrics include metrics selected from the group consisting of;

a symbol error rate, a bit error rate, a frame error rate, a packet error rate, and power spectral density.

5. The method defined in claim 4, wherein the test station further includes a test host and wherein directing the tester to wirelessly broadcast the initialization signals in the radio-frequency channel to each of the plurality of devices under test comprises:

with the test host, directing the tester to wirelessly broadcast the initialization signals in the radio-frequency channel to each of the plurality of devices under test.

6. The method defined in claim 5, further comprising:

with the test host, directing the tester to wirelessly broadcast initialization and test radio-frequency signals in an additional radio-frequency channel to each of the plurality of devices under test.

7. The method defined in claim 6, further comprising:

removing the plurality of devices under test from the test chamber; and

with the test host, gathering calculated downlink sensitivity data from each of the plurality of devices under test.

8. The method defined in claim 7, wherein each of the plurality of devices under test comprises cellular telephone circuitry and wherein wirelessly broadcasting the test signals to the plurality of devices under test at the first output power level in the radio-frequency channel comprises:

wirelessly broadcasting the test signals to the cellular telephone circuitry in each of the plurality of devices under test at the first output power level in the radio-frequency channel.

9. The method defined in claim 2, wherein wirelessly broadcasting the test signals to each of the plurality of devices under test at the first output power level in the radio-frequency channel comprises:

wirelessly broadcasting the test signals to each of the plurality of devices under test over a non-protocol-compliant communications path.

10. A method of testing a plurality of devices under test with a test station, wherein the plurality of devices under test are not electrically connected to the test station, the method comprising:

configuring each of the plurality of devices under test to sequentially receive radio-frequency signals in a plurality of radio-frequency channels in accordance with a common ordered list of predetermined channels to be tested; and

with the test station, performing downlink testing by sequentially broadcasting radio-frequency signals in each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested.

11. The method defined in claim 10, wherein the test station comprises a tester, a test host, and a test chamber and wherein performing downlink testing comprises:

with the test host, directing the tester to sequentially broadcast the radio-frequency signals in each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested, wherein each of the plurality of devices under test are placed in the test chamber and wherein the radio-frequency signals are wirelessly transmitted to each of the plurality of devices under test over a non-protocol-compliant path.

12. The method defined in claim 11, wherein performing downlink testing further comprises:

with each of the plurality of devices under test, receiving the radio-frequency signals broadcast from the tester; and

with each of the plurality of devices under test, measuring a corresponding radio-frequency performance metric for the received radio-frequency signals.

13. The method defined in claim 12, wherein measuring the corresponding radio-frequency performance metric comprises:

measuring a metric selected from the group consisting of;

a symbol error rate, a bit error rate, a frame error rate, a packet error rate, power spectral density, and a receive signal strength indicator.

14. The method defined in claim 13, wherein directing the tester to sequentially broadcast the radio-frequency signals in each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested comprises:

directing the tester to broadcast the radio-frequency signals at different output power levels for each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested.

15. The method defined in claim 14, further comprising:

with each of the plurality of devices under test, computing a downlink sensitivity value for each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested when the measured radio-frequency metric fails to satisfy a user-specified threshold.

16. The method defined in claim 15, wherein each of the devices under test comprises cellular telephone transceiver circuitry and wherein computing the downlink sensitivity value comprises:

with each of the plurality of devices under test, computing the downlink sensitivity value for the cellular telephone transceiver circuitry of that device under test at each of the plurality of radio-frequency channels in the common ordered list of predetermined channels to be tested.

17. A radio-frequency test station with a test chamber in which a plurality of devices under test are tested, comprising:

a test host;

a tester; and

an antenna within the test chamber that is coupled to the tester, wherein the tester transmits radio-frequency signals to the devices under test through the antenna during wireless testing and wherein the plurality of devices under test are disconnected from the test host.

18. The radio-frequency test station defined in claim 17, wherein the test chamber comprises a transverse electromagnetic cell.

19. The radio-frequency test station defined in claim 17, wherein the antenna comprises a microstrip antenna.

20. The radio-frequency test station defined in claim 17, wherein the tester comprises a signal generator.

21. The radio-frequency test station defined in claim 17, wherein the test chamber comprises a room.

22. The radio-frequency test station defined in claim 17, wherein the test chamber comprises a radio-frequency shielded room.