4 ms·
Is this anything like how phased-array radar works?
by StuffMaster 12y ago
Is this anything like how phased-array radar works?
- lpmay 12y agoI think the "phased-array radar" you're referring to would be more precisely called "active-phased-array radar". Yes, the concepts are similar. By providing a calibrated time delay between elements of the array, the direction of focusing can be controlled. I'm not sure how this is done in practice for actual radars. If it is done in hardware, the array would have a single steerable pattern. If instead each array element has a clock-synchronized direct conversion digitizer, the beamforming can be done in the digital domain and the number of logical beams would be limited by the DSP capacity available.
- madengr 12y agoThat is a good summary. Some radars use phase shifters, and some true time delay elements. They are equivalent for narrow bandwidths, but the true time delay is needed for wide bandwidths.
- lpmay 12y agoThanks! In case anyone else is interested: the distinction between phase delay and time delay comes into play if bandwidth is large as you say, but in one more case as well. If the array is large enough that the time delay across the array is on the order of a symbol period you must use a true time delay. If you use a phase delay instead of a true time delay, energy from separate symbols will be added together to make the final bit decision and the resulting ISI will increase BER.