A phased array.

Tom Jeffrey has written:

'Phased-array radar design' -- subject(s): Radar, Phased array antennas, Design and construction

A Phased array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. This is particularly useful in a 3D plane where the object changes co-ordinates, in different directions.

Kurt A. Shalkhauser has written:

'Rain-fade simulation and power augmentation for satellite communication systems' -- subject(s): Artificial satellites in telecommunication

'Bit-error-rate testing of high-power 30-GHz traveling wave tubes for ground-terminal applications' -- subject(s): Communication systems, Astronautics, Bit error rate, Traveling wave tubes

'Bit-error-rate testing of fiber optic data links for MMIC-based phased array antennas' -- subject(s): Phased array antennas, Data links, Digital data, Bit error rate, Fiber optics, Phased arrays

'High-performance packaging for monolithic microwave and millimeter-wave integrated circuits' -- subject(s): Phased array antennas, Microwave integrated circuits

I am giving you an Answer but still not sure if this is right !

Phased array system:

Phased array system consists of many elements which are pulsed sequentially at different time intervals and hence this avoiding the usage of different angle Probes.In Phased array system the the 64 channels are integrated in a single casing hence only one probe is used.

In TOFD system is mainly designed to overcome the difficulties and complications faced in the Radiographic testing.In TOFD system there are different channels with a separate Transmitter and Receiver.The number of channels is directly Propotional to the thickness and hence more the number of channels,more thickness the waves can travel.