The semicircle is not an operational amplifier, although it can also be made of an operational amplifier, but it is a logical AND gate. The operational amplifier with a hole in the front is actually a logical NOT gate. In fact, in this circuit, there are digital parts, that is, circuits composed of logic gates, that is, those relatively small triangular half-moons. For logic gates, a hole indicates the opposite direction, which can also be considered as a non-gate. Because your diagram is incomplete, I can't tell you the specific function of this circuit. This circuit may control the signal processing. I suggest you know some representations of logic gates first, and then you will understand this diagram better. The one with square chip should be Schmidt trigger, which is used for shaping, and the one without square chip is the usual comparator.