| 摘要 |
PURPOSE:To obtain a phasing circuit for received wave of a good S/N ratio by installing a control device, by which a noise after addition of every output is memorized by a storage-readout device in a period neither transmission nor reception is carried out, and this content of storage is read out and a difference from a received signal is repeatedly processed in a reception period. CONSTITUTION:Input received signals from respective transducers, which are arranged in order, are phased and added by an adding device 3 after setting desired delays to the respective signals with delay devices 2-1, 2-2,... and switching devices 3-1, 3-2,.... But in case of forming mode B image of an ultrasonic image pick-up apparatus, neither transmission nor reception of ultrasonic wave is carried out in a period that a frame synchronous signal X is at level 'H' and in a section that signal Y is 'A'. Therefore, the same delay switching as those in the sections 'B1', 'B2',... is carried out to generate a switching noise in 'A' section, the switching noise in an output (a) of the adding device 3 is stored in a noise storage-readout device 4, and then in the sections 'B1'' 'B2',..., the stored noise is repeatedly read out and differences between signals (b) and signal (a) are processed by a differential amplifier (6), so that signals (c), which have a noise eliminated, are obtained. A phasing circuit for received wave of good S/N ratio is obtained as a result. |
