This kind of EO sensor has an additional phase delay caused by natural binary refraction, which is very sensitive to the temperature that thereby influences the signal transmission quality. Moreover, the phase delay of this kind of EO sensor depends on the aspect ratio of EO crystals, which results in the comparatively big size of the EO sensor and will limit its application in BSNs. In our previous works, we proposed a novel signal transmission method based on the human body medium by using a Mach-Zehnder EO sensor, which will help to achieve signal transmission based on the human medium with the characteristics of good temperature dependence properties, small size and low power consumption [9].
In this paper, we present a signal transmission system based on the proposed method, and the frequency response properties as well as the parameters of the proposed system have been discussed. Firstly, we described the proposed signal transmission system, which consists of a transmitter, a Mach-Zehnder EO sensor and a corresponding receiving circuit. Secondly, the advantage with respect to the frequency response of the signal transmission based on the human body medium by using the proposed system has been verified by using in-vivo measurements. Furthermore, in order to determine the suitable parameters, the corresponding in-vivo signal transmission experiments with different carrier frequencies, baseband frequencies and multi-paths were implemented.
Results indicate that the proposed method will help to achieve reliable and high speed signal BSN transmissions for healthcare and the other related fields.
The rest of the paper is organized as follows. Section 2 describes the signal transmission system based on human body medium. Section 3 mainly focuses on the experiments and results discussion. Section 4 concludes the paper.2.?Signal Transmission SystemGenerally, Dacomitinib the signal transmission approaches based on the human body medium can be divided into two types, which include electrostatic coupling type and galvanic coupling type [6,10]. Compared with the latter type, the former has the characteristic of less signal attenuation, which is very important for decreasing power consumption.
Therefore, in our investigation AV-951 the electrostatic coupling type was chosen as the approach for signal transmission based on the human body medium.2.1. System StructureThe developed signal transmission system based on the human body medium is composed of a transmitter, a Mach-Zehnder URL List 1|]# EO sensor and a receiving circuit, as shown in Figure 1. In the developed system, a baseband signal is input to the transmitter through the input port first, and then it is modulated and amplified in the transmitter.