| Communications Blockset | |
Results and Display
To examine the performance of the demo, double-click the switches to bring up error rate display and instrumentation.
The error rate display shows three types of error rates:
The raw bit error rate displays the inconsistencies between the bits in the transmitted signal and the received signal. Frame error rate refers to the ratio of frame failure to the total number of frames. Frame failure, caused by noise and interference, is determined if the HEC fails to match the header info or if less than 57 bits are correct in the access code. If the frame fails, this is captured by a zero-valued Frame OK signal, which is used in the FER calculation as well as to exclude bad frames from the residual BER calculation.
The Instrumentation brings up the spectrum of the transmitted Bluetooth signal (narrow-band) with IEEE 802.11b interference. The timing diagram for the Bluetooth and interferer slots is also available. A dynamic plot of packet frequency versus time is shown by the Spectrogram plot. The thin lines are the Bluetooth transmissions, while the larger, more colorful blocks are the interferer slots. Most of the time, due to frequency hopping, there is not much overlap of these slots. In a few cases, the signals do collide, as the Spectrogram plot clearly shows.
Reference
| | Mask Variables | Digital Video Broadcasting Demo | |