a beamformer for an array of sonar transducers , or electromagnetic radiating elements , includes mixers for translating the signals received by the transducers to a lower frequency . the beamformer incorporates delay lines operating at a clock rate which is reduced in proportion to the decrease in frequency . each delay line provides delays to the signals of corresponding ones of the transducers in accordance with the time of arrival of a wavefront of radiation upon the respective transducers . phase shifters coupled between the mixers and the delay lines impart phase shifts to the transducer signals proportional to the respective delays to compensate for the lowering of the frequency .