This relates generally to testing wireless electronic devices and, more particularly, to testing multiple wireless electronic devices placed in a test chamber.
Wireless electronic devices typically include transceiver circuitry, antenna circuitry, and other radio-frequency circuitry that provide wireless communications capabilities. During testing, wireless electronic devices under test (DUTs) can exhibit different performance levels. For example, each wireless DUT in a group of DUTs can exhibit its own output power level, gain, frequency response, efficiency, linearity, dynamic range, downlink sensitivity, etc.
The performance of a wireless DUT can be measured using a radio-frequency (RF) test station. A radio-frequency test station typically includes a test host, a tester (i.e., a signal generator), and a test chamber. The signal generator is connected to the test host. Connected in this way, the test host configures the signal generator to transmit downlink radio-frequency signals during test operations.
In conventional radio-frequency test arrangements, a single wireless DUT having a cellular telephone transceiver is placed into the test chamber. The DUT is connected (tethered) to the test host using a radio-frequency cable. Tethering the DUT to the test host provides an undesired ground path for noise to be injected into the DUT.
The test host directs the signal generator to wirelessly broadcast radio-frequency downlink test signals at a first output power level to the cellular telephone transceiver of the DUT. A protocol-compliant data link is established between the signal generator and the DUT (i.e., radio-frequency signals are conveyed between the signal generator and the DUT over the protocol-compliant data link).
The cellular telephone transceiver receives the downlink test signals. The test host directs the DUT to measure a symbol error rate for the received downlink test signals. If the measured symbol error rate is satisfactory (i.e., greater than 10%), the test host directs the signal generator to broadcast downlink test signals at a second output power level that is less than the first output power level. If the measured symbol error rate is unsatisfactory (i.e., less than 10%), the current output power level represents the downlink sensitivity of cellular telephone transceiver (i.e., the DUT notifies the test host that downlink sensitivity has been obtained).
Once the downlink sensitivity has been determined, the DUT is disconnected from the test host (i.e., by unplugging the radio-frequency cable from the DUT) and is removed from the test chamber. To test additional DUTs, a new DUT is connected to the test host (i.e., by plugging the radio-frequency cable into a corresponding mating connector in the new DUT) and is placed into the test chamber.
Wireless testing using this conventional approach may be inefficient, because the process of connecting a DUT to the test host, placing the DUT in the test chamber, testing the DUT, removing the DUT from the test chamber, and disconnecting the DUT from the test host one DUT at a time is time-consuming. Moreover, protocol-based testing allows testing of only a single DUT and requires more tedious measurement processes. Protocol-compliant testing also has a tendency to drops calls when the output power falls below the downlink sensitivity. Re-establishing the protocol compliant calls in order to complete testing can add significant time and cost to the test process.
It would therefore be desirable to be able to provide improved ways of performing sensitivity testing.