In recent years, some progress has been made in the development of software radio technology, but it still faces many technical challenges, including high-speed A/D, DSP digital processing, RF front-end, antenna technology, etc. It can be said that these technologies determine the development and implementation of software radio. The efforts in this area have never stopped, and these technologies are still developing constantly, and some new development trends have emerged. The antenna portion of an ideal software radio system should cover all wireless communication bands and be able to communicate unobstructed over a wide range of operating frequencies. At present, a multi-band combined antenna is used, that is, a plurality of antennas are combined in a full frequency band or even in each frequency band to form a broadband antenna. Broadband antennas are considered to be the best antenna solution for implementing an ideal software radio system and are considered to be unachievable at the current state of the art. The RF RMEMS(R) MEMS developed in recent years is a highly compact device that can be used as a small switch to replace the high cost, large volume PIN diode, ultra wideband FET and vacuum relay VTR in the antenna. It is a breakthrough technology for implementing broadband reconfigurable antenna design. With MEMS, the operating frequency of an annular slotted antenna can be changed electronically. On a slotted antenna of one type, when the circumference is approximately one wavelength, good performance can be obtained at a certain frequency. When the antenna is reconstructed for the new frequency band, the entrance of the different slotted antenna unit can be exchanged. Export. Therefore, it is possible to perform frequency conversion in the range of 3-8 GHz. MEMS switches implemented with PIN diode switches also have the advantages of low loss, high isolation and small size. In addition, new antenna unit technologies are emerging to design and manufacture broadband WB and ultra-wideband UWB antennas for SDR, including ultra-wideband “resistive†resistive antennas and “curve†antennas MLA. The application of MEMS technology will reduce the size and cost of WB and UWB antennas by orders of magnitude. Additional advances in modeling and simulation methods enable accurate simulation of these new antenna elements. At present, the level of RF components can only support about 20% of the bandwidth, so the technical solution adopted in the existing software radio system is to cover the entire frequency band by using a set of RF modules. RF modules may also be required to be replaced when multiple standards are supported. With the maturity of wide-band synthesis technology and low-noise high-performance semiconductor process technology, very flexible RF modules emerge. The highly miniaturized multi-band multi-mode MBMM RF chip was put into production in 2003, and the superconducting RF technology helps to achieve the performance required for commercial multi-band multi-mode front-ends. These two technologies are currently becoming mainstream SDR technologies and will be available in 2005. RF MEMS technology is a new device technology with low loss and small size, which can realize a high-performance high-performance device, which will apply the volume, weight and power consumption of multi-band multi-mode RF chip. And the cost is reduced by an order of magnitude, and the processing speed and processing power of the chip are improved, enabling the digital signal processor to perform the modulation and demodulation function. In addition, the movable characteristics of MEMS devices can dynamically adjust the parameter values ​​of components, thereby greatly improving the performance and flexibility of multiple RF devices, including low phase noise voltage controlled oscillators based on MEMS high Q resonators, MEMS-based variable Wideband transformers and phase shifters for capacitor and switched capacitor networks, tunable filters based on MEMS variable reactance units and switches. Programmable bandpass filters are critical in transmitters and receivers to ensure efficient channel utilization and high sensitivity, while at the same time being the most cost-effective device in the RF module group. Software radios require these units to Electronically constructed or superimposed to form a filter bank. The latter approach is currently used in most software radio systems, and it is reported that high Q MEMS based filters have been demonstrated. Superconducting technology is also considered. This technology enables a tunable bandpass filter with overspeed roll-off characteristics. At present, a tuned filter with an intermediate frequency of 3.5 and a tuning range of 620 MHz is realized by a superconducting germanium film process. The process features low loss and allows the design and implementation of multi-stage diaphragm filters with low insertion loss and wideband capability. The location of the A/D and D/A converters in the software radio system is critical, and it directly reflects the degree of softwareization of the software stations. For an ideal software radio, the dynamic range of the A/D converter must be between 100-120dB or 16-20 bits, and the maximum input signal frequency should be between 1GHz and 5GHz. With regard to current state of the art, it is difficult to achieve these technical requirements. In the past two years, with the application of modern deep submicron technology, a variety of A/D converter structures have emerged: ∑△ structure and tubular structure. The advantage of the ∑Δ structure A/D converter is that it can provide a large dynamic range and high linearity, but the conversion speed is limited. To increase speed, the key is to improve the structure, such as reducing the resampling rate, reducing the problem of multi-bit loop and high-order loop stability, and optimizing the bandwidth of the amplifier required. The tubular A/D converter can achieve the highest conversion rate, but the resolution can only be limited to 13-14 bits. Higher resolution and conversion rates can be achieved by optimizing the entire structure, including advanced calibration circuitry and error correction algorithms, resulting in a larger dynamic range. According to related research, hybrid-structured converters, such as tubular ∑△ structures or tubular folded plug-in A/D converters, are promising concepts that not only combine the advantages of different structures in terms of resolution and conversion rate. And it also has error correction algorithms, reduced power consumption and the ability to adapt to different environments. The first A/D converter with a resolution of more than 4 bits and a conversion rate exceeding 1Gsampless has been released. Although at the expense of power consumption, the trend toward ultra-high-speed A/D converters is clearly visible. Patent Vape,E-Cigarette Vape Pens,E-Cigarette Vaporizer Pen,Disposable Vape Puff Bar Guangzhou Yunge Tianhong Electronic Technology Co., Ltd , https://www.e-cigaretteyfactory.com