In a smart antenna like the automatic DF Antenna, there are several elements of antenna arrays, an omnidirectional reference antenna, four phase shifters, a summing stage and a switch matrix.
The SignalShark controls and synchronizes the switch matrix with its extremely fast internal measurement unit.
A complete bearing cycle consists of several measurement steps. During each bearing cycle the omnidirectional channel power and the spectrum are measured.
The level of the omnidirectional element and the level of the antenna element 1 shifted four times in phase are measured. With this, SignalShark determines the magnitude and phase of the covariance between antenna element 1 and the omnidirectional reference element.
The measurement in step 1 will be repeated for every antenna element.
A measured covariance vector with a complex covariance value for each antenna element is the interim result which is later on used to calculate the bearings.
The omnidirectional channel power and the spectrum are measured.
The duration of a single measurement step is the result of the measurement time and some delay time for switching.
The cycle time consists of:
1 x omnidirectional measurement |
+ |
9 x 4 antenna element measurements |
= |
37 steps |
The minimum cycle time depends also on the CBW.
In general: Broader CBWs allow shorter cycle times down to 1.2 ms