R&S®SMU-B14 Fading Simulator
When signals are sent from the transmitter to the receiver, various fading effects occur. Thus, multiple propagation paths may be superimposed on each other either constructively or destructively. In addition, the movement of the receiver relative to the transmitter creates a frequency shift. The R&S® SMU200A fading simulator makes it easy to simulate these conditions in the lab. This is the only way to optimize receiver performance.
A total of 40 fading paths at 80 MHz bandwidth and 10 ns time resolution are available for simulating multipath propagation. If higher time resolution is needed (10 ps), the bandwidth (30 MHz and 50 MHz) and the number of fading paths (24 and 16) can be modified. Since up to two baseband generators and RF paths can be installed on the R&S® SMU200A, it is easy to simulate the receive conditions of a receiver that has two antennas (e.g. a UMTS base station). This eliminates the problems usually associated with cabling and synchronization since the entire scenario is created in a single R&S® SMU200A.
Simplest setting of the preferred fading
The user interface was designed for easy and straightforward operation. Thus, it includes fading profiles for the most common mobile radio standards (e.g. GSM/EDGE, 3GPP, CDMA, TETRA, WLAN). To handle special test requirements, the fading profiles can also be configured as needed. The graphical display of the fading paths provides an overview of the situation at all times. It shows the number of paths, timing, relative power and the fading profile that is used.
The R&S®SMU200A supports multipath fading with the following profiles:
- Static path
- Pure Doppler
- Rayleigh
- Rician
- Constant phase
- Lognormal
- Suzuki
Furthermore, it supports scenarios introduced by 3GPP such as birth-death propagation (testing of receiver performance for disappearance and reappearance of a signal, such as when a caller walks around the corner of a building while on the phone) and moving delay propagation (testing of receiver performance for slow changes in delay).
Relation between the number of fading paths, bandwidth and time resolution 10 ps with option SMU-K71
Examples
Measurement of the IQ signal with an oscilloscope
Rician fading of a squarewave-filtered QPSK signal (change in amplitude and phase)
Demonstration of moving delay fading with ASK modulation. The second path moves relative to the first path
Setup for simulating transmit diversity
