In an apparatus for multi-pole acoustic logging while drilling, a N-cycle sinusoidal wave signal is generated by utilizing a signal processor, and amplified into a high-voltage sinusoidal excitation signal by utilizing a power amplifier, and output to a transmitting transducer. The signal processor simultaneously generates an enable signal. The enable signal includes a transient discharge enable signal. The power amplifier is connected with a transient discharge circuit. After the signal processor generates N cycles of a sinusoidal wave, the transient discharge enable signal enables the transient discharge circuit to discharge to release an energy storage current of a power transformer so as to eliminate a high-voltage ringing effect and improve an excitation efficiency of the transducer.

A radiofrequency (RF) amplifier includes an input terminal, an output terminal, and a power supply and biasing stage having an output coupled to the input terminal. An amplification stage of the RF amplifier includes a first transistor having a control terminal coupled to the input terminal and a first conduction terminal coupled to the output terminal. The power supply and biasing stage is configured to generate a bias voltage at the control terminal of the first transistor to simultaneously regulate a power supply voltage of the amplification stage to a first voltage and a bias current of the amplification stage to a first current.

A capacitive gain amplifier circuit includes two sets of Miller capacitors and two output stage differential amplifier circuits. A first set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a first phase that resets the first output stage differential amplifier circuit. The second set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a second phase that chops a signal being amplified. The second set of Miller capacitors is swapped from one polarity to an opposite polarity of the first output stage differential amplifier circuit during successive second phases. The second output stage differential amplifier circuit includes a set of inputs selectively coupled with the inputs of the first output stage differential amplifier circuit and a set of outputs selectively coupled with the outputs of the first output stage differential amplifier circuit during the second phase.

A capacitive gain amplifier circuit amplifies an input signal by a pair of differential amplifier circuits couples in series. The first differential amplifier circuit is reset during an autozero phase while disconnected from the second differential amplifier circuit, and the first and second differential amplifier circuits are connected together in series during a chop phase. A set of feedback capacitors is selectively switched in between respective outputs of the second differential amplifier circuit and respective inputs of the first differential amplifier circuit during the chop phase.

A linear power source circuit includes: an input unit to which an input signal is input and which outputs a first current signal; a current-voltage convertor which converts the first current signal into a first voltage signal; a voltage-current convertor configured to convert the first voltage signal into a second current signal; and an output unit configured to generate an output voltage signal from the second current signal by a first current mirror unit, a second current mirror unit, and a third current mirror unit, and configured to output the output voltage signal to an output terminal. The input unit and the current-voltage convertor constitute a current feedback type operational amplifier.