Multipath Fading Emulator
The Multipath Fading Emulator (MFE) is a Skytechnology IP software product developed to emulate the multipath fading effect typical of wireless communication channels.
The MFE is targeted to work with National Instruments’ Vector Signal Transceiver family of products, a software-defined instrument that combines a vector signal analyzer and a vector signal generator with a user-defined FPGA for real-time signal processing and control.
The MFE IP consists of the FPGA programming file for the VST and a LabView user interface to control the instrument.
- Vector signal generator- analyzer
- Frequency from 65 MHz to 6 GHz
- Instant bandwidth up to 200 MHz
- 24 i/o high speed digital channels
- Programmable with LabVIEW FPGA
- l/Q base band interface (optional)
The MFE IP’s architecture adheres to the underlying hardware: calibration, signal acquisition, processing and generation tasks are carried in real-time on the user-defined FPGA, while system/test configuration and HMI are managed at the software level, on an integrated PXI Controller.
Parameters are logically grouped by functionalities; tabbed graph displays the signal in the time domain, its spectrum. Cursors on the display simplify user measurements.
The HMI let the user easily modify instrument parameters, all of them at run-time, thus allowing the operator to instantaneously see modifications.
MFE IP offers following testing features:
- Notch filter control: user may vary both notch frequency and depth at the same time;
- Notch sweep: this feature allows the conduction of automatic sweep of notch frequency over a definable frequency range.
- Propagation delay: whilst it is customary to conduct signature test at 6.3 ns, the software lets the user move the delay as needed, with a resolution better than 0.5 ns.
- Noise insertion: the instrument lets the user to add noise to the output signal, either uniform or Gaussian.
- Flat fading: the software allows the user to process the input stream by super-imposing a flat-fading effect.
- Continuous wave interference insertion: the user may add up to two narrow-band interferences, controlling CW frequency and attenuation independently for each of them.
- Input/output stream display: the software lets the user to select in real-time whether to display the input signal or the processed one. In this way user can investigate both input/output signals without additional external instrumentation.
- Local oscillator compensation: the software offers the possibility to set adjust factors to compensate for unwanted LO spurs contribution. Compensation has to be carried out measuring the output signal with a spectrum analyzer. The software offers the possibility to input adjust factors to compensate for unwanted LO spurious contribution.
- Different Frequency in/out: the instrument may use different clock rates for input and output streams.
- Slew rate:all the following parameters vary with a definable slew-rate:
- Notch frequency and depth
- Noise intensity
- NB frequency and intensity
- FF intensity
Slew rate control allows the operator to perform several tasks like avoiding modem errors/communication interruptions or characterizing the DUT’s operational limits and determining devices’ operational ranges.
- Automatic execution of auto calibration: the application automatically manages hardware calibration in order to carry out correct measurements.
The supported version depending on the National Instruments’ VST is:
MFE _200M (for NI PXI-5646R)