Many manufacturers of BLE components find it challenging to test modules and sensors in compliance with the standard when developing nodes and sensors for the internet of things (IoT). These devices often have no port or interface to connect to a control line for testing them in direct test mode (DTM) as stipulated by the Bluetooth LE standard. The R&S CMW test platform from Rohde & Schwarz now enables over-the-air (OTA) tests as well as conducted measurements on these devices.
When drafting the BLE test specifications in 2010, Bluetooth SIG specified a direct test mode (DTM, non-signaling) but did not specify an OTA signaling test mode. DTM requires a dedicated control line to be connected to the device under test. The control line, however, does not allow RF tests under realistic conditions since the measured RF characteristics are distorted compared with a realistic test.
Testing BLE components in direct test mode at the board level during development is a complicated but feasible task. In contrast, it is difficult or even impossible to carry out DTM RF tests in production and for OTA applications, e.g. in shielded chambers. Many BLE devices offer no port or interface to connect to a control line but nevertheless need to be tested under realistic conditions.
The BLE signaling test solution from Rohde & Schwarz makes it possible to determine the RF characteristics of a Bluetooth LE device via a Bluetooth OTA link or over a wired connection to the antenna. With this approach, users can, for example, measure the level, modulation and receiver characteristics of individual or all data channels for frequency-hopping transmissions, which are typical of Bluetooth.
Rohde & Schwarz also offers an advertiser testing option for its R&S CMW test platform to measure the RF parameters of advertiser channels. The BLE signaling functionality enhances the BLE direct test mode and the BLE advertiser mode. With these functionalities, it is now possible to solve even