Patent ID: 7905839

Claim:
An ultrasonic observation apparatus connecting to an ultrasonic probe to be inserted into a body cavity, which outputs transmit signals in a pulse shape to an ultrasonic transducer internally contained in the ultrasonic probe, the apparatus comprising: a secondary circuit having a ground connecting to a cabinet of the ultrasonic observation apparatus; a patient circuit insulated in direct current from the cabinet and the ground; a timing signal generating circuit provided in the secondary circuit and generating timing signals for generating the transmit signals; an insulating circuit with two channels including a first insulating circuit and a second insulating circuit insulating the timing signals from the secondary circuit and transmitting the timing signals to the patient circuit; and a transmit signal generating circuit provided in the patient circuit and generating the transmit signals in synchronization with the inputted timing signals, wherein the timing signal generating circuit generates multiple pieces of digital signal data for creating the transmit signals and includes a digital-analog converting circuit for generating analog first signals in a waveform compliant with the transmit signals from the multiple pieces of digital signal data; the first insulating circuit insulates and transmits the first signals so as to be inputted to an amplifying circuit included in the transmit signal generating circuit; and the second insulating circuit controls turning on and off the amplifying circuit such that the amplifying circuit performs amplification only in the vicinity of the period when the first signals are inputted to the amplifying circuit by transmitting second signals generated by the timing signal generating circuit in synchronization with the first signals and applying the transmitted second signals to the amplifying circuit.