– High-Performance RF and Functional Test of Automotive Infotainment and eCall Modules –

Multi-DUT testing with the NOFFZ UTP 9010

The introduction of new automotive safety regulations (such as eCall within the European Union) and the growing number of vehicles with Network Access Devices (NAD) is creating a continuously increasing need for cellular and wireless module testing.

The result is a requirement for shorter test times per DUT combined with a higher throughput in general. This can only be achieved by using RF instruments more efficiently through instrument sharing or Multi-DUT testing.
Based on HARMAN’s requirements, NOFFZ developed a test system for four DUTs in parallel.
The test system combines all requirements for end-of-line testing on board-level at HARMAN: Flashing, functional and RF tests.

The main test software is based on NI TestStand. Beside several PXI and PCI cards for audio, voltage and current measurements the NOFFZ Signal Conditioning Unit is used to route the measurement signals, test antenna diagnosis functionalities as well as to perform typical sleep mode current measurements and digital control of other functionalities.

The adapter contacts four DUTs in parallel in different ways:

  • Via needles (70-80 from bottom)
  • With one movable block via several Fakra, Rosenberger HSD and the System Connector
  • Via an RF antenna in a partially shielded area

One of the challenges was to connect multiple USB-connections with multiple virtual COM ports to one PC. Since the system stability is highly dependent on the vendor’s driver and the Windows COM port-alignment, NOFFZ and HARMAN chose Linux-based interfaces between the IPC and each DUT to reach an improvement in stability.

RF Testing with the NI Wireless Test System

Since RF Test Equipment is considered a high value asset, two major requirements came up for choosing the right instrument: total system cost as well as RF performance. Based on the experience of NOFFZ and HARMAN with the NI Vector Signal Transceiver and RF Non-Signaling-Tests, the NI Wireless Test System was chosen as the best fit between lower investment costs and higher RF performance.

The NI Wireless Test System is a “multi-up” RF test instrument with up to 16 ports and intelligent software, which aligns the internal Vector Signal Generators and Vector Signal Analyzers very efficiently to the tasks of RF testing. As a system for high volume production test, the deployed version of the NI WTS has 16 ports with robust RF connectors.
By connecting four DUTs with four ports each (Cellular main and diversity antenna, GNSS and Bluetooth/WLAN), the hardware is fully used.
Different chip sets from various vendors integrated into the HARMAN DUT can all be tested with the same instrument.

As an example, the following RF Tests for Cellular, Bluetooth, WLAN and GNSS were implemented:As an example, the following RF Tests for Cellular, Bluetooth, WLAN and GNSS were implemented:

  • Realization of test specification for Cellular Non-Signaling tests like
    • Error Vector Magnitude (EVM)
    • TX Occupied Bandwidth (OBW)
    • TX Power (TXP) all necessary bands
    • TX Spectral Emission Mask (SEM)
    • RX Bit Error Rate (BER) at -100dBm
    • Received Signal Strength Indication (RSSI)
  • Realization of test specification for WLAN Non-Signaling tests like
    • Measurements for all standards:802.11abgnpac
    • TX: Adjacent Channel Power (ACP), Spectral Emission Mask (SEM), Occupied Bandwidth (OBW), Error Vector Magnitude (EVM)
    • RX: Packet Error Rate (PER)
  • Realization of test specification for Bluetooth Non-Signaling tests like
    • TX: Output Power (TXP), LO Leakage, Adjacent Channel Power (ACP), Modulation Accuracy, IFCT, Carrier Drift
    • RX: Packet Error Rate (PER), Sensitivity
  • Realization of test specification for GNSS Signaling (single- or multiple satellite signals) or Non-Signaling RF tests with sensitivity and Signal-to-Noise Ratio (SNR) measurements.


The overall test system shows very good test results and significantly shorter test-times compared to previously used approaches such as Signaling-Test or sequential RF testing based on Single-up RF instruments. By selecting NOFFZ as the system integrator, development time was decreased because of NOFFZ’s experience in RF Multi-DUT-testing as well as existing libraries for DUT control of different RF chipsets. The selection of NOFFZ and NI was key to the success of the project – the close partnership between the two companies as well as the local RF testing expertise of both companies allowed a flexible system to be deployed quickly.