As is known to all, many auscultations of human body, such as heart, lung and carotid artery sound, play a major role in clinic.And their signal frequency is in the range that computer sound card can handle, so we can use analog-to-digital (A/D) conversion of sound card as A/D conversion (ADC) of auscultation signals, and double-channel auscultation signals (DCASs) can be input into personal computer(PC) by sound card that every computer has, and it makes the hardware design more simple.Because auscultation signals are input from sound card, any common music processing software (CMPS) can be used to process received auscultative signals, and it is not necessary to write special processing software for them.Therefore, only a double-channel and front-end analog signal processing circuit of auscultation is needed to be designed.By this method of constituting the signal collecting system for double-channel auscultation, it is simple and low cost, and needs no special software, so it has very important values and a broad market prospect.

Simulated signal, produced by digital to analog converter, is important and necessary in many fields, such as electronic experiment, equipment debugging and maintenance, especially, in medical area. In this paper, the design and application of an effective software which may be used to generate simulated signal data by special wave picture obtained by scanner or drawing software are presented. First, we introduce how to realize producing needed data that meet the given conditions including amplitude, samples and resolution by this software. Second, the method and steps of getting the stimulated signal data from wave figure file is given. Third, an example of application about this software to generate simulated physiological signal data is shown. Then, the data are put into use and by digital to analog converter, an idea stimulated signal is produced. Therefore, with full confidence, we could draw a conclusion that it is very convenient and effective to get needed data for digital to analog conversion to generate all kinds simulated signal with a novel method.

A digital-controlled measuring instrument for hearing, which is mainly composed of STC11F16EX, AD9833, ISD400416MS and LM1972, is introduced in this paper. It may output highly accurate and purified sine signal whose frequency and amplitude are controlled by digital data. Specially, the displaying number of decibel is equal to actual number of decibel because that frequency response of earphone is corrected through software of microcontroller. Additionally, touching buttons, which is simple and convenience to use, is selected. Hence this instrument is convenient to measure and teach about hearing specially, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science.

An open-ended and multifunctional double-channel signal generator, which based on a 32 bits monolithic integrated microcomputer, highly integrated device and LCD, is introduced in this paper. The instrument is composed of micro-computer STM32F103RD and some integrated chips (IC), which includes programmable waveform generators-AD9833 with highly frequency and phase precision. As a result, this signal generator may output not only double channels accurate sine, square or triangle waveforms with digital-controlled frequency and phase at the same time, but also many kinds of physiological signals that can be modified by USB connection with well open property. Therefore, it is convenient to measure and teach about hearing, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science. In addition, it is also very easy in experiment and research of college and medical physics for using double channels sine signal to show synthesis of two simple harmonic vibrations under different frequency, phase difference and direction, such as beat pattern and Lissajous figures. Thus it has many merits, such as the small volume, stable property, simple operation, visual display and so on. Consequently, it can be widely used in researching, teaching, debugging and maintaining.