twcny spectrum

Understanding of discrete Fourier transform (d)------complex form of discrete Fourier transform the discrete Fourier transform is very ingenious to use the complex method, making Fourier transform transformation more natural and concise, it is not simply to use the replacement method to use the complex Number, but to analyze the problem completely from the plural point of view, which is completely different from the real DFT.One, to represent a positive cosine function as a plural formThe positi

Understanding of discrete Fourier transform (d)------complex form of discrete Fourier transform the discrete Fourier transform is very ingenious to use the complex method, making Fourier transform transformation more natural and concise, it is not simply to use the replacement method to use the complex Number, but to analyze the problem completely from the plural point of view, which is completely different from the real DFT.One, to represent a positive cosine function as a plural formThe positi

each otherTo make better use of the system bandwidth, the sub-carrier can be spaced as close as possible.Figure 12: Close to FDM, in practice, considering the hardware implementation, demodulation of the first signal, it is difficult to completely remove the impact of the second signal (the implementation of the circuit after all, can not be as neat as scissors cutting paper), the two signals may have caused interference with each otherCan you come closer? OK. This is the origin of OFDM, ah, ne

broadband access network business development in different regions and different application scenarios, the maximum bandwidth of VDSL2 can reach 30 MHz. For bandwidth below 12 MHz, the Plan997 and Plan998 bandwidths of VDSL are adopted. Among them, Plan997 is suitable for the application mode of Bidirectional symmetric rate of medium and short distance, while Plan998 is suitable for the application mode of downlink high speed of medium and short distance. Plan997 and Plan998 have a variety of e

Cognitive Radio (CR) technology effectively relieves the conflict between the lack of spectrum resources and the increasing demand for wireless access through secondary exploitation of the authorized spectrum, people are getting more and more attention. To enable CR users to use spectrum holes and avoid harmful interference to authorized users, the Media Access C

difficult to completely remove the impact of the second signal (the implementation of the circuit after all, can not be as neat as scissors cutting paper), the two signals may have caused interference with each otherCan you come closer? OK. This is the origin of OFDM, ah, nearly equal to the Nyquist bandwidth (detailed later), so that the frequency band utilization reached the theoretical maximum value.Figure 13: Continue closer, the interval frequency is orthogonal to each other, so the

Cognitive radio (CR) technology has been paid more and more attention by the way of "two utilization" of the authorized spectrum, which effectively relieves the contradiction between the lack of spectrum resources and the increasing demand for wireless access. In order to realize CR users ' use of spectrum holes while avoiding harmful interference to authorized

1 Introduction More and more applications require sampling analog signals, converting them into digital signals, performing various calculations and processing on digital signals, and then converting them into analog signals. This article discusses how to sample analog signals and shaping them to preserve the original signal. 2 baseband signal sampling and mixing analysis Starting with the finite bandwidth signal, the finite bandwidth signal refers to the signal with a

increasing popularity of 4G services, the promotion of traffic consumption will become more obvious. At the same time, the traffic characteristics of the mobile Internet era also show obvious asymmetry. According to the actual measurement data of some operators in the European, American, and Japanese markets, the downstream data traffic is generally 4 ~ of the upstream traffic ~ 9 times. It can be said that the rapid growth of data traffic consumption and obvious asymmetry reflect the main need

Understanding Discrete Fourier Transformation (4) ------ complex form discrete Fourier transformation uses the complex method very cleverly, making the Fourier transformation more natural and concise, it does not simply use the replacement method to use the plural, but analyzes the problem from the perspective of the plural, which is totally different from the real DFT. I, Returns the positive cosine of a number.Through the Euler's equation, the positive cosine function can be expressed as a com

plural number, which is totally different from the real DFT.1. Represent the positive cosine function in the form of a plural number. through the Euler's equation, the positive cosine function can be expressed as a complex number: CoS (X) = 1/2 e j (-x) + 1/2 ejx sin (x) = J (1/2 e j (-x)-1/2 ejx) From this equation, we can see that after the positive cosine function is expressed as a complex number, they become a positive cosine wave composed of positive and negative frequencies. On the c

Now, wireless designers are faced with the arduous task of designing world-class products. Many wireless technical standards define the technical indicators of power, but ignore the specific steps of Power Measurement. Therefore, designers often encounter Errors During measurement. Because the ofdm rf waveforms used in IEEE 802.16 are complex, more errors occur when measuring mobile WiMAX signals. This article describes important information about WiMAX channel power measurement. These basic pri

Fourier series are used in periodic signals, while Fourier transforms are applied in periodic and aperiodic signals. It is also possible to cycle the signal with Fourier series, while the energy signal uses the Fourier transform (because the energy signal is non-periodic except for all 0). Fourier transform/progression is just an analytical tool that is used to analyzeSpectrum of. Spectrum generally refers to the frequency content of the signal,

straight line. Therefore, the basic unit in the frequency domain can be understood as a circle that is always rotating. It's a pity that you cannot upload a dynamic graph ...... For more information about motion graphs, click here: File: Fourier series square wave circles animation.gif And here: File: Fourier series sawtooth wave circles animation.gif If you click out, don't be turned off and run on Wiki. Where are the articles written on Wiki. After introducing the basic component units in

, many different types of wireless technologies and applications are rapidly emerging to meet this growing demand. It should be emphasized that there are some unique challenges in the industrial field, but many traditional wireless technologies are not designed specifically to address these challenges. These challenges include the ability to require high reliability, low system power consumption, good performance in a physical environment with severe RF interference, and of course cost-effective

With the rapid development of communication service and the surge of traffic, the future mobile communication system should not only have large system capacity, but also can support the effective transmission of voice, data, image, multimedia and other services. The third generation mobile communication system combines high speed mobile access and internet-based protocol services to provide users with more economical and richer wireless communication services while increasing the wireless freque

) variables. The spatial domain is the coordinate system spanned by f (x, y) . The spectral components of the spectrum system in the four corners of the spectrum graph are obtained by 0. The discrete Fourier inverse transformation is given by the following formula:So that R and I represent the real and required parts of F respectively, then the Fourier spectrum,

China's LTE commercialization is approaching, and the industry's attention to the subsequent evolution of LTE has reached a new peak. Compared with 3G, LTE significantly improves the spectrum efficiency. However, the industry has not stopped. A few years ago, 3GPP began to research and develop the LTE-Advanced standard, and a series of technologies that can effectively improve the performance of existing LTE Networks emerged. Among them, the two most

discrete signal is a continuous pulse, because the Fourier series coefficient of the discrete signal is cyclical, but continuous is not of this nature ); At last, continuous signals can only move the spectrum to a finite band, while discrete signals will continue to shift (however, in fact, the spectrum is 2 π, 4 π, 6 π, and so on, which is the same as 0, therefore, the low frequency is an even number of t

1: What are the characteristics of TDD technology? L Time Division Duplex (TDD): distinguishes uplink and downlink based on different time slots P advantages N when the upstream and downstream services are asymmetrical, different quantities of time slots can be flexibly allocated to the upstream and downstream operations, resulting in high spectrum efficiency. N uplink and downlink use the same frequency carrier, which facilitates the introduction of